US20070107659A1 - Transport mechanism for disk-shaped workpieces - Google Patents
Transport mechanism for disk-shaped workpieces Download PDFInfo
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- US20070107659A1 US20070107659A1 US11/588,165 US58816506A US2007107659A1 US 20070107659 A1 US20070107659 A1 US 20070107659A1 US 58816506 A US58816506 A US 58816506A US 2007107659 A1 US2007107659 A1 US 2007107659A1
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- workpiece
- cassette
- transport
- transport mechanism
- wafer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/677—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations
- H01L21/67763—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations the wafers being stored in a carrier, involving loading and unloading
- H01L21/67766—Mechanical parts of transfer devices
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/402—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/677—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations
- H01L21/67763—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations the wafers being stored in a carrier, involving loading and unloading
- H01L21/67778—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations the wafers being stored in a carrier, involving loading and unloading involving loading and unloading of wafers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/68—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment
- H01L21/681—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment using optical controlling means
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
- H01L21/68707—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a robot blade, or gripped by a gripper for conveyance
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/40—Robotics, robotics mapping to robotics vision
- G05B2219/40562—Position and orientation of end effector, teach probe, track them
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S414/00—Material or article handling
- Y10S414/135—Associated with semiconductor wafer handling
- Y10S414/141—Associated with semiconductor wafer handling includes means for gripping wafer
Definitions
- the invention relates to a transport mechanism for disk-shaped workpieces, in particular for semiconductor wafers.
- such facilities preferably include a lock chamber, where the wafers are moved from the atmospheric environment into a vacuum chamber and subsequently into a process station or, as a rule, sequentially into several process stations in order to be able to carry out the required surface treatment.
- a transport device With the aid of a transport device the wafers are delivered in a horizontal transport plane from the lock chamber into the process chamber, and after the wafer has been deposited in the process chamber, the latter is, as a rule, closed in order to be able to carry out the process under the required vacuum and process conditions. If several process steps are necessary, the wafer is again transported out of the one process chamber in the same manner and, for the next process step, is transported into another process chamber.
- Especially preferred types of facilities are so-called cluster systems.
- the lock chamber and the process chamber, or the several chambers are arranged peripherally about the substantially central transport chamber.
- these chambers are arranged in a type of star-shaped configuration about the centrally located transport chambers.
- the transport device in this case is located in this centrally located transport chamber and has access, on the one hand, to the at least one lock chamber and, on the other hand, to the process chamber.
- a so-called lock valve is disposed in order to be able to partition the chambers against one another during the locking process or during the process step.
- the transport device subsequently extends appropriately through the open lock gates in order to deposit the wafer at the designated location.
- the transport device moves the wafer translatively in one plane and consequently in two directions of motion.
- the device is conventionally formed as a mechanism which pivots about a center of rotation and forms therewith the one rotating direction of motion and which can execute a further second translatory motion radially with respect to the center of rotation back and forth away from/to this center of rotation.
- this transport device for example a length-adjustable arm mechanics rotatable in the horizontal plane, the wafer to be transported is subsequently deposited in the end region of this arm.
- Such a configuration can in this case readily also transport a wafer over relatively great path distances, for example of the orders of magnitude of 1 m or more, from a lock chamber into the transport chamber and from here, in turn, into and out of the process chamber and extend through the corresponding opened lock doors.
- the wafer is deposited under atmospheric pressure onto the transport mechanism as precisely as possible and always in the same position in order to be able to transport it subsequently also precisely to a predetermined position.
- the deposition of the wafer on the transport mechanism, as well as also the transport mechanism itself is afflicted with imprecisions or with tolerance errors. Further imprecisions or shifts of the wafer position on the transport mechanism can also occur in the process station due to effects in the process chamber.
- a particular problem in the handling of disk-shaped workpieces occurs if the workpieces are very thin relative to the diameter and deflect correspondingly strongly. This is in particular the case with semiconductor wafers, which have perhaps a thickness of a few tenths of a millimeter, such as preferably 0.07 to 0.3 mm at a diameter of 100 mm to 300 mm. Depending on the type of support the deflection may be in the range on a few tenths of a millimeter up to a few millimeters. This makes precise handling and positioning within a transport configuration considerably more difficult especially since the deflection can be of different magnitudes.
- EP 0 696 242 B2 discloses a transport mechanism for semiconductor wafers which permits lifting and depositing circular semiconductor disks, or disk-shaped workpieces, with the aid of a height-adjustable handling robot rotating about its axis with a carrying arm or carrying element extensible in the horizontal plane or to deposit them and bringing them into a different position. Therewith it is possible for example to remove workpieces with a transport arm from a cassette and transport them into a different position, where they can, for example, be worked. In vacuum process facilities the workpieces must be moved in and out through a lock, be that from atmospheric pressure into the facility or within the facility between different chambers.
- the previously described transport arm of the robot if needed and under control, reaches through the corresponding lock gates for the transportation of the workpiece to the correct target location.
- cassettes are utilized which can hold several workpieces in a small space and can be employed either outside of the facility and/or inside the facility.
- the arrangement introduced in the patent permits realizing transport mechanisms of this type.
- the underlying assumption in these known transport mechanisms is that the workpiece remains flat as defined and that its dimensions are also defined.
- the handling as well as also the substrate acquisition with the appropriate electronic or optical sensors build on these prerequisites.
- the present invention addresses the task of eliminating the previously listed disadvantages of prior-art.
- the task consists in particular in realizing a mechanism and a method for the transport of thin flexible disk-shaped workpieces, in particular of semiconductor disks, which permit high precision and reliability, in particular as much as possible without workpiece defects, with which high economy in the production process can be attained.
- the task is solved through a transport mechanism for workpieces according to the invention and with a method according to the invention.
- the claim define the various advantageous embodiments of the invention.
- the solution is comprised by permitting the deflection of the flat workpiece up to the natural form and the handling and detecting takes this deformation of the workpiece into consideration and is referenced and oriented to positions or places which are clearly defined at the beginning of the transport process and are maintained during the entire process. All handling and detection elements are focused under consideration of the tolerance ranges and their limits which are given mechanically and electrically through the participating mechanism in the process facility referenced to the starting position of the workpiece in the process facility. The process facility is so realized that none of the regions not located within these clearly defined zones can have a significant effect on the function or the reliability of the transport or handling process.
- the invention comprises a transport mechanism for disk-shaped workpieces, in particular for semiconductor wafers, with a controlled, horizontally movable transport arm at the one end of which two elongated carrying elements are disposed at a spacing for the substantially horizontal reception of the workpiece and that a cassette is provided which at two opposing sides has a comb structure for the substantially horizontal reception of several workpieces, the carrying elements and the comb structure being formed such that they can be introduced free of contact between two adjacent spaced-apart combs of the comb structure with the workpieces potentially disposed therein for the lifting or deposition of a workpiece with the aid of an additional vertical motion relative with respect to the cassette and the transport arm, the carrying elements being disposed such that during the cassette engagement they are substantially each positioned adjacent parallel to the comb structure along a comb and that in this region along and between two adjacent comb planes on one side and/or both sides of the cassette a scanning beam is provided for acquiring a workpiece and its position, and that the scanning beam can be height-positioned relatively with respect
- FIG. 1 a disk-shaped workpiece, such as a semiconductor wafer, in top view and in different cross sections with different examples of deflection,
- FIG. 2 a a workpiece in the region of the support with the maximally possible deflections
- FIG. 2 b a workpiece in top view with defined possible support regions, the handling zones,
- FIG. 3 a a cassette in cross section with several workpieces deposited therein and partially bent
- FIG. 3 b a cassette in top view with a workpiece
- FIG. 4 a a cassette in cross section corresponding to FIG. 3 a
- FIG. 4 b a detail of the cassette with comb structure on one side with a workpiece in the region of the support
- FIG. 4 c a workpiece in top view with the resulting permissible handling zones
- FIG. 5 a workpiece in top view with demonstration of the support on the carrying elements which are overlaid within the permissible handling zones
- FIG. 6 a a workpiece in cross section with demonstration of the scanning beams along the comb structure
- FIG. 6 b in cross section workpieces deposited in the cassette with different possible deflections
- FIG. 6 c a detail according to FIG. 6 b on one side of the cassette in the region of the support and in cross section with respect to the scanning beam,
- FIG. 6 d in top view a workpiece in the cassette with demonstration of the imaging zones of the scanning beam on the workpiece
- FIG. 7 a in cross section a bent workpiece with support on posts
- FIG. 7 b in top view a workpiece according to FIG. 7 a with carrying elements guided under the workpiece
- FIG. 8 a in cross section workpieces deposited in a cassette which are bent with a warp
- FIG. 8 b in cross section a detail in the proximity of the comb structure of the cassette according to FIG. 8 a,
- FIG. 8 c in top view a workpiece with warp deposited on carrying elements
- FIG. 8 d in cross section a workpiece with warp with formed carrying element
- FIG. 9 a in top view a carrier plate for workpieces with radially disposed carrying elements
- FIG. 9 b in top view a further carrier plate for workpieces with circularly disposed carrying element
- FIG. 10 a in top view a transport device with two transport robots
- FIG. 10 b in top view a configuration for the orientation of workpieces.
- Vacuum process facilities may also comprise several process stations, which are tended with one or several handling robots.
- the flat disk-shaped workpieces 7 are conventionally transported in the horizontal direction.
- handling robots which can be rotated about their own axes 66 , 67 and which have a transport arm 61 , 60 which can be extended in the horizontal direction laterally to the rotational axis 66 , 67 , in order to be able to transport a workpiece 7 in the lateral direction to these axes, such as is schematically shown in FIG. 10 a in top view.
- the receiving or depositing of the workpiece takes place thereby that the carrying elements 26 , 27 are moved under the workpiece 7 and subsequently is lifted or deposited with a vertical relative motion from the cassette 20 or a base 62 , 42 , 54 through relative movement.
- the relative movement is generated thereby that either the cassette or the base is correspondingly moved vertically or preferably the handling robot is moved correspondingly vertically.
- These processes must be carried out highly precisely and no grinding or frictional movements must be generated at the participating elements, which would lead to undesirable abrasion and particle formation, which would unfavorably affect the sensitive vacuum processes and would lead to rejects in the production.
- the situation is additionally made difficult if thin large-area disk-shaped workpieces 7 are to be worked and must be transported since such workpieces can have a strong deflection or warp and may thereby impair the reliable function of the transport mechanism.
- increasingly greater diameters of workpiece disks are utilized today and these are additionally increasingly becoming thinner, whereby the bending problem is exacerbated.
- FIG. 1 shows as the workpiece a semiconductor wafer with different types of possible deflections.
- a relatively thick wafer 2 has essentially no deflection and rests flat on the supports 1 .
- Thin wafers can deflect downwardly 3 due to their own weight or upwardly 4 due to internal stress.
- deflections conventionally have cylindrical form, however, they may also be formed of a combination of several cylindrical forms, which are oriented differently. This combination of deflections subsequently leads to a deflection profile 5 , which has a saddle-shaped warping of the wafer.
- these are introduced in cassettes containing several wafers. In such cassettes 20 the wafers rest with their margin region in contact on stays guided in parallel, such that the surface of the workpiece is substantially free. Only the zone of the wafer in the region of the stayed region is hereby well defined in the vertical position independently of the magnitude of the deflection of the workpiece. This position can be characterized through two support lines 6 , which form two chords in the region of the periphery of the wafer 7 . Locations on the wafer face too far removed from these support lines 6 , are not known or not defined in their vertical position.
- the system tolerance region 8 in the vertical direction is determinant, as is shown in FIG. 2 a in cross section. If the maximally possible deflections upwardly 9 and downwardly 10 of the workpiece are taken into consideration, an angle deviating from the horizontal results, the upward angle 9 and the downward angle 10 with respect to support 1 , from which subsequently the maximum handling zone width 11 can be defined, which define the handling zones 12 , 13 on the workpiece on both sides. Thus, virtually two spaced-apart, parallel strip-shaped handling zones 12 , 13 result, which are located in the peripheral region of the disk-shaped workpiece, as is depicted in top view in FIG. 2 b.
- stop means 16 , 17 In order to limit or to define the horizontal position of the workpiece 7 in the cassette, stop means 16 , 17 must be provided which only occupy as spots the interior region of the cassette between the supports 18 , 18 ′ or permit in the region of the supports and the handling zones 12 , 13 the detection means to extend between and along them. Thin rod-shaped elements 16 , 7 are therefore preferred as the stop means.
- the cassette 20 has a comb-shaped structure 18 , 18 ′ on both sides, which forms a slot-form configuration capable of receiving and staying the disk-shaped workpieces 7 in the peripheral region. The cassette 20 thereby forms a configuration with several receiving slots for the reception of several workpieces 7 .
- the comb structure has a comb distance 19 large enough to avoid that adjacently inserted workpieces 7 do not come into contact even in the presence of deflections. If, for example, workpieces 3 are utilized which bend downwardly and workpieces 2 which are flat, the comb distance 19 must be greater than the downwardly directed deflection 3 of the workpiece 7 . If workpieces 7 are utilized, which deflect upwardly as well as downwardly, the comb distance 19 must be greater than the sum of the maximally expected bending upwardly and downwardly.
- carrying elements 21 , 22 are located at the end of the robot carrying arm, onto which the workpiece 7 is deposited.
- a carrying element mounting 28 is disposed and on this mounting two elongated spaced-apart carrying elements 26 , 27 are disposed in parallel, which are preferably formed in the shape of rods, as is depicted in FIG. 5 in top view.
- FIG. 5 shows the manner in which a disk-shaped workpiece, a semiconductor wafer 7 , is deposited on the carrying elements 26 , 27 .
- the thickness of the carrying elements 26 , 27 is limited, this means they must be sufficiently thin such that these [verb missing: provide separation(?)] between two adjacent workpieces 7 in the cassette without touching it for the succeeding lifting process or after the deposition of a workpiece 7 in the cassette.
- the carrying elements 26 , 27 are therefore preferably implemented in the form of rods and must have sufficient rigidity in order not be bent in an undesirable manner which would additionally increase the handling tolerances.
- FIG. 4 a depicts by example a wafer 3 in a cassette 20 , which is bent downwardly compared to a flat wafer 2 , both located in slots of the cassette,. The downwardly bent wafer 3 is to be lifted and removed from the cassette slot with the carrying elements 26 , 27 .
- the maximally permissible thickness 21 of the carrying element 26 , 27 is a function of the available interspace between the superjacent and subjacent wafers 3 , 2 and the handling tolerances required to move the wafer into the cassette or out of it, as is shown in cross section in FIG. 4 b in detail in the critical margin region.
- the greatest possible distance between the adjacent wafers 2 , 3 corresponds substantially to the comb distance 19 , whose position forms the outer position of the permissible handling zone width 23 and the inner limit of the permissible handling zone width 23 is spaced somewhat further away from the comb structure 18 toward the inside, which is limited by the diameter 21 of the carrying element 26 , 27 and depends on the deflections of the wafers 2 , 3 , without coming into mutual contact. From these two possible positions results the permissible handling zone width 23 , which determine the permissible handling zones 24 , 25 , and must lie within the handling zone 12 , 13 , as is depicted in FIG. 4 b and 4 c.
- Known imaging systems utilize for example reflecting laser systems, in which the read sensor 29 and the reflector 30 are disposed parallel to the wafer surface and oppositely outside of the wafer.
- the read sensor 29 is also the source of the laser scanning beam 31 , which extends also parallel to the wafer surface and is reflected in the reflector 30 back onto the read sensor 29 .
- This beam arrangement with scanning beam 31 , read sensor 29 and reflector 30 is guided in known manner close to the region of the center line of the wafer plane. If a wafer is moved into the region of the scanning beam 31 , the latter is interrupted and the position is detected.
- the read sensor 32 and the associated reflector 33 for thin wafers is to be disposed oppositely outside of the plane of the wafer 2 , 3 , 4 and the read sensor 32 and the reflector 33 is additionally to be disposed somewhat offset outside of the wafer plane, such that the scanning beam 35 is guided slightly tilted with respect to the planar wafer plane 2 , from which a preferred tilt angle 34 in the range of 0.50 to 2.00 results.
- the small tilt angle 34 of the scanning beam 35 generates a projection of the wafer in the direction of the scanning beam 35 such that a significantly greater thickness 36 , the so-called apparent thickness 36 , seems present than the involved wafer, in fact, has.
- the scanning beam 35 for thin bendable wafers 2 , 3 , 4 with the read sensor 32 and the reflector 33 are disposed in the margin region of the wafer periphery, thus in the proximity of the comb structure 18 , 18 ′ of cassette 20 . Consequently, with a viewing direction in the scanning beam direction not a dot-form beam appears as is conventional in known systems, but rather an apparent thickness 36 of wafer 2 , 3 , 4 depending on the magnitude of the scanning beam tilt angle 34 as is depicted in detail in cross section in FIG. 6 c.
- the scanning beam 34 consequently has the capability of acquiring, apart from planar wafers 2 , also corresponding upwardly or downwardly deflected wafers 3 , 4 , whereby the second problem can also be solved.
- the one limit results through the tips of the comb structure 18 , 18 ′ at which an upwardly bent wafer 4 and a downwardly bent wafer 3 were to intersect if these wafers 3 , 4 were to lie in an adjacent slot of the comb structure 18 , 18 ′. Consequently two conditions must be maintained in order to be able to detect reliably thin bendable wafers. Firstly, as stated, the apparent thickness 36 in the region of the tilted scanning beam 35 must be greater than the maximally possible distance d in the laser beam region from an upwardly bent wafer 4 and between a downwardly bent wafer 3 , if these were to lie in the same slot of cassette 20 .
- the actual determined handling zone width 39 for the measuring system lies within the maximal imaging zone width 38 .
- the two imaging zones 40 , 41 which are located on both sides of the wafer near the comb structures 18 , 18 ′ of cassette 20 , within which the scanning beam 35 can be guided and with the read sensor 32 and reflector 33 located outside of the line. In this way within the imaging zone 40 , 41 every deformed thin wafer at any location within these zones can be reliably detected.
- the handling of the wafer is conventionally so carried out that it is positioned and deposited on a flat surface 42 before it is worked in the process station, as is shown in cross section in FIG. 7 a.
- the original support position is generated as in the cassette with supports, which are referred to the handling zones 12 , 13 on the wafer.
- wafer support posts 54 also referred to as pins, on which the wafer 3 rests and which ensure that the distance between base 42 and wafer 3 is large enough to allow carrying elements 26 , 27 to be introduced between them as is shown in FIG. 7 a and 7 b.
- the wafer support posts 54 for this procedure are preferably raised, whereby the wafer 3 is lifted from the base 42 and, if it is appropriately thin, is also deflected.
- the wafer base 42 can also be moved in the vertical direction and holding elements other than the so-called wafer support posts 54 can also be utilized for generating the distance between wafer and base 42 .
- the carrying arms 26 , 27 In the retracted state of the carrying arms 26 , 27 , for lifting or depositing the wafer 3 on the base, the latter lies exclusively in contact in the region of the defined handling zones 12 , 13 for the transport procedure, with these arms being held on the carrying element mounting 28 , which is secured on the robot arm as is shown in FIG. 7 b in conjunction with an example of a semiconductor wafer 7 .
- each of the carrying elements 47 is provided with one step 48 in the peripheral region of wafer 46 such that the wafer 46 can deflect downwardly in the central region and thereby can adapt to a predetermined desired form, preferably to a planar surface in order to be able to accept essentially the previously made considerations directly.
- further steps can preferably be provided in order to be able to secure the wafer there on the carrying element 47 in order to avoid during the transport that the wafer becomes displaced during the transport movement. It is also of advantage to fabricate the carrying element 47 of a material or to coat it with a corresponding material such that a greater surface friction results to decrease the previously described effect.
- the wafer rotation orientation station where wafers are oriented in their planar orientation with respect to a workpiece marker 7 a.
- a wafer which has reached this station is conventionally by definition not oriented to the corresponding marker 7 a.
- This means that the support axes are randomly oriented with respect to the wafer marker 7 a .
- the purpose of this station is to bring the wafer into a clearly defined rotation position in order to work it further. This means that the wafer must be rotated. This rotation movement also leads to a rotation of the support lines about the center of the wafer, which means the support lines before and after the orientation are different.
- a circular support base is advantageously realized for the wafer, which is as close as possible to the support lines or imaging zones 40 , 41 .
- a support plate 50 is utilized which has a circular support means 51 with a diameter approximating very closely the diameter of the position of the imaging zones 40 , 41 .
- two or more robot systems are employed in order to handle the workpieces and to transport them.
- An important configuration is for example that in which a first robot 60 is positioned on a facility at atmospheric pressure at the so-called front end, as it is referred to in the semiconductor industry, whereby wafers are transported in and out in cassettes.
- the second robot 61 can then be positioned in the vacuum process facility, thus under vacuum conditions, in order to transport wafers into the process station and out of the process station.
- a substrate transfer station 62 is placed between the two robots 60 , 61 .
- this substrate transfer station is not located on the connection line between the two robot rotation centers 66 , 67 , the wafers 7 placed by the first robot system onto the position 63 do not have the correct angular orientation with respect to the second robot system at which position 64 would be necessary as is shown in FIGS. 10 a and 10 b.
- the substrate transfer station 62 must be provided with means 65 which permit rotating the wafer about the angular difference between the two required wafer positions 63 , 64 .
Abstract
A transport mechanism for disk-shaped workpieces has a horizontally movable transport arm with two elongated carrying elements at one end, for receiving the workpiece. A cassette which includes a comb structure at each side for receiving several workpieces, is inserted free of contact between two adjacent combs with workpieces therein for vertically lifting a workpiece. The carrying elements are disposed such that during a cassette engagement they are each positioned substantially adjacent and parallel to the comb structure along a comb, and that in this region along and between two adjacent comb planes on one side of the cassette, a scanning beam is provided for workpiece acquisition, and that the scanning beam is relatively height-positionable with respect to the cassette. The scanning beam is tilted about a small angle with respect to the horizontal workpiece plane.
Description
- The invention relates to a transport mechanism for disk-shaped workpieces, in particular for semiconductor wafers.
- In modern vacuum process facilities circular flat substrates or workpieces, which are also referred to as wafers, are surface treated, such as for example coated, etched, cleaned, thermally treated etc., in such fully automated vacuum process systems. In order to automate such processes and to be able to carry out multi-stage processes in different facility areas, automated transport systems, a type of handling robot, are employed. In particular the treatment of semiconductor wafers in such processes requires very high quality of treatment, such as in particular high cleanliness, high precision and careful treatment of the substrates. Due to the stated high requirements, such facilities preferably include a lock chamber, where the wafers are moved from the atmospheric environment into a vacuum chamber and subsequently into a process station or, as a rule, sequentially into several process stations in order to be able to carry out the required surface treatment. With the aid of a transport device the wafers are delivered in a horizontal transport plane from the lock chamber into the process chamber, and after the wafer has been deposited in the process chamber, the latter is, as a rule, closed in order to be able to carry out the process under the required vacuum and process conditions. If several process steps are necessary, the wafer is again transported out of the one process chamber in the same manner and, for the next process step, is transported into another process chamber. Especially preferred types of facilities are so-called cluster systems. In such systems, the lock chamber and the process chamber, or the several chambers, are arranged peripherally about the substantially central transport chamber. In the case of more than one lock chamber and in particular in the case of several process chambers, these chambers are arranged in a type of star-shaped configuration about the centrally located transport chambers. The transport device in this case is located in this centrally located transport chamber and has access, on the one hand, to the at least one lock chamber and, on the other hand, to the process chamber. Between the transport chamber and the remaining chambers conventionally and preferably a so-called lock valve is disposed in order to be able to partition the chambers against one another during the locking process or during the process step. During the transport process of a wafer, the transport device subsequently extends appropriately through the open lock gates in order to deposit the wafer at the designated location.
- The transport device moves the wafer translatively in one plane and consequently in two directions of motion. In said preferred cluster systems with the transport device disposed in the central transport chamber, the device is conventionally formed as a mechanism which pivots about a center of rotation and forms therewith the one rotating direction of motion and which can execute a further second translatory motion radially with respect to the center of rotation back and forth away from/to this center of rotation. On this transport device, for example a length-adjustable arm mechanics rotatable in the horizontal plane, the wafer to be transported is subsequently deposited in the end region of this arm. Such a configuration can in this case readily also transport a wafer over relatively great path distances, for example of the orders of magnitude of 1 m or more, from a lock chamber into the transport chamber and from here, in turn, into and out of the process chamber and extend through the corresponding opened lock doors. At the beginning of the transport cycle the wafer is deposited under atmospheric pressure onto the transport mechanism as precisely as possible and always in the same position in order to be able to transport it subsequently also precisely to a predetermined position. However, the deposition of the wafer on the transport mechanism, as well as also the transport mechanism itself, is afflicted with imprecisions or with tolerance errors. Further imprecisions or shifts of the wafer position on the transport mechanism can also occur in the process station due to effects in the process chamber.
- A particular problem in the handling of disk-shaped workpieces occurs if the workpieces are very thin relative to the diameter and deflect correspondingly strongly. This is in particular the case with semiconductor wafers, which have perhaps a thickness of a few tenths of a millimeter, such as preferably 0.07 to 0.3 mm at a diameter of 100 mm to 300 mm. Depending on the type of support the deflection may be in the range on a few tenths of a millimeter up to a few millimeters. This makes precise handling and positioning within a transport configuration considerably more difficult especially since the deflection can be of different magnitudes. Especially problematic is the handling or transfer of semiconductor disks from a cassette into the designated positions, such as process stations or chambers of a vacuum process facility. In such facilities the semiconductor wafers are deposited horizontally in magazines formed as cassettes and again removed horizontally from them, in order to intermediately store them on compact space. Special difficulties are encountered with wafers which deflect strongly, with respect to handling precision and desired compactness of the configuration and reliability of the handling.
- EP 0 696 242 B2 discloses a transport mechanism for semiconductor wafers which permits lifting and depositing circular semiconductor disks, or disk-shaped workpieces, with the aid of a height-adjustable handling robot rotating about its axis with a carrying arm or carrying element extensible in the horizontal plane or to deposit them and bringing them into a different position. Therewith it is possible for example to remove workpieces with a transport arm from a cassette and transport them into a different position, where they can, for example, be worked. In vacuum process facilities the workpieces must be moved in and out through a lock, be that from atmospheric pressure into the facility or within the facility between different chambers. The previously described transport arm of the robot, if needed and under control, reaches through the corresponding lock gates for the transportation of the workpiece to the correct target location. Depending on the concept of the facility, for the intermediate storage of the workpieces cassettes are utilized which can hold several workpieces in a small space and can be employed either outside of the facility and/or inside the facility. The arrangement introduced in the patent permits realizing transport mechanisms of this type. The underlying assumption in these known transport mechanisms is that the workpiece remains flat as defined and that its dimensions are also defined. The handling as well as also the substrate acquisition with the appropriate electronic or optical sensors build on these prerequisites.
- However, for large-area thin workpieces, which deflect strongly, considerable problems are encountered with this mechanism and a solution of them is not provided. In these cases such transport mechanisms are correspondingly functionally also operated at their limit, which decreases the operational reliability of such facilities.
- The present invention addresses the task of eliminating the previously listed disadvantages of prior-art. The task consists in particular in realizing a mechanism and a method for the transport of thin flexible disk-shaped workpieces, in particular of semiconductor disks, which permit high precision and reliability, in particular as much as possible without workpiece defects, with which high economy in the production process can be attained.
- According to the invention the task is solved through a transport mechanism for workpieces according to the invention and with a method according to the invention. The claim define the various advantageous embodiments of the invention.
- According to the invention the solution is comprised by permitting the deflection of the flat workpiece up to the natural form and the handling and detecting takes this deformation of the workpiece into consideration and is referenced and oriented to positions or places which are clearly defined at the beginning of the transport process and are maintained during the entire process. All handling and detection elements are focused under consideration of the tolerance ranges and their limits which are given mechanically and electrically through the participating mechanism in the process facility referenced to the starting position of the workpiece in the process facility. The process facility is so realized that none of the regions not located within these clearly defined zones can have a significant effect on the function or the reliability of the transport or handling process.
- The invention comprises a transport mechanism for disk-shaped workpieces, in particular for semiconductor wafers, with a controlled, horizontally movable transport arm at the one end of which two elongated carrying elements are disposed at a spacing for the substantially horizontal reception of the workpiece and that a cassette is provided which at two opposing sides has a comb structure for the substantially horizontal reception of several workpieces, the carrying elements and the comb structure being formed such that they can be introduced free of contact between two adjacent spaced-apart combs of the comb structure with the workpieces potentially disposed therein for the lifting or deposition of a workpiece with the aid of an additional vertical motion relative with respect to the cassette and the transport arm, the carrying elements being disposed such that during the cassette engagement they are substantially each positioned adjacent parallel to the comb structure along a comb and that in this region along and between two adjacent comb planes on one side and/or both sides of the cassette a scanning beam is provided for acquiring a workpiece and its position, and that the scanning beam can be height-positioned relatively with respect to the cassette, the scanning beam with respect to horizontal workpiece plane being guided at a small-angle tilt.
- The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure and are entirely bases on the priority application no. 2005 01843/05 filed in Switzerland on Nov. 17, 2005, incorporated here by reference. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
- In the following the invention will be explained in further detail by example and in conjunction with schematic figures. In the drawing depict:
-
FIG. 1 a disk-shaped workpiece, such as a semiconductor wafer, in top view and in different cross sections with different examples of deflection, -
FIG. 2 a a workpiece in the region of the support with the maximally possible deflections, -
FIG. 2 b a workpiece in top view with defined possible support regions, the handling zones, -
FIG. 3 a a cassette in cross section with several workpieces deposited therein and partially bent, -
FIG. 3 b a cassette in top view with a workpiece, -
FIG. 4 a a cassette in cross section corresponding toFIG. 3 a, -
FIG. 4 b a detail of the cassette with comb structure on one side with a workpiece in the region of the support, -
FIG. 4 c a workpiece in top view with the resulting permissible handling zones, -
FIG. 5 a workpiece in top view with demonstration of the support on the carrying elements which are overlaid within the permissible handling zones, -
FIG. 6 a a workpiece in cross section with demonstration of the scanning beams along the comb structure, -
FIG. 6 b in cross section workpieces deposited in the cassette with different possible deflections, -
FIG. 6 c a detail according toFIG. 6 b on one side of the cassette in the region of the support and in cross section with respect to the scanning beam, -
FIG. 6 d in top view a workpiece in the cassette with demonstration of the imaging zones of the scanning beam on the workpiece, -
FIG. 7 a in cross section a bent workpiece with support on posts, -
FIG. 7 b in top view a workpiece according toFIG. 7 a with carrying elements guided under the workpiece, -
FIG. 8 a in cross section workpieces deposited in a cassette which are bent with a warp, -
FIG. 8 b in cross section a detail in the proximity of the comb structure of the cassette according toFIG. 8 a, -
FIG. 8 c in top view a workpiece with warp deposited on carrying elements, -
FIG. 8 d in cross section a workpiece with warp with formed carrying element; -
FIG. 9 a in top view a carrier plate for workpieces with radially disposed carrying elements, -
FIG. 9 b in top view a further carrier plate for workpieces with circularly disposed carrying element, -
FIG. 10 a in top view a transport device with two transport robots, -
FIG. 10 b in top view a configuration for the orientation of workpieces. - In fully automated vacuum process facilities for the surface working of disk-shaped workpieces and in particular of semiconductor wafers of silicon and/or germanium it is necessary to transport these precisely with robot devices. The transport of these workpieces from one position into the other position must take place such that it is precisely reproducible and without causing damage to the workpiece.
Several workpieces 7 are for this purpose deposited into acassette 20 or removed from it, in order to be transported for example from atmospheric pressure into a vacuum through a lock, in order to be subsequently worked. After the working in a process station, for example after coating or etching of the workpiece, these are again guided back with the aid of the handling robot through the lock into the cassette. Vacuum process facilities may also comprise several process stations, which are tended with one or several handling robots. In such process facilities the flat disk-shapedworkpieces 7 are conventionally transported in the horizontal direction. For this purpose are employed handling robots, which can be rotated about theirown axes transport arm rotational axis workpiece 7 in the lateral direction to these axes, such as is schematically shown inFIG. 10 a in top view. The receiving or depositing of the workpiece takes place thereby that the carryingelements workpiece 7 and subsequently is lifted or deposited with a vertical relative motion from thecassette 20 or abase workpieces 7 are to be worked and must be transported since such workpieces can have a strong deflection or warp and may thereby impair the reliable function of the transport mechanism. To increase the economy in the semiconductor production further, increasingly greater diameters of workpiece disks are utilized today and these are additionally increasingly becoming thinner, whereby the bending problem is exacerbated. Today disk diameters of 100 mm to 300 mm are utilized having thicknesses of 0.07 mm to approximately 0.6 mm. Depending on the ratio, deflections result therefrom which are in the range of a few tenths millimeter or may even go up to several millimeters. - For the support of
workpieces 7 two line-form supports 1, which form the carryingelements FIG. 1 . The line-form supports 1 are substantially aligned parallel to one another and spaced apart from one another such that the disk-shapedworkpiece 7 is stayed in the margin region on both sides along thesupport line 6 on thesupports 1. These twosupports 1 are preferably formed as rod-shaped carryingelements FIG. 1 shows as the workpiece a semiconductor wafer with different types of possible deflections. A relativelythick wafer 2 has essentially no deflection and rests flat on thesupports 1. Thin wafers can deflect downwardly 3 due to their own weight or upwardly 4 due to internal stress. These deflections conventionally have cylindrical form, however, they may also be formed of a combination of several cylindrical forms, which are oriented differently. This combination of deflections subsequently leads to adeflection profile 5, which has a saddle-shaped warping of the wafer. In standard vacuum process facilities for working semiconductor disks, these are introduced in cassettes containing several wafers. Insuch cassettes 20 the wafers rest with their margin region in contact on stays guided in parallel, such that the surface of the workpiece is substantially free. Only the zone of the wafer in the region of the stayed region is hereby well defined in the vertical position independently of the magnitude of the deflection of the workpiece. This position can be characterized through twosupport lines 6, which form two chords in the region of the periphery of thewafer 7. Locations on the wafer face too far removed from thesesupport lines 6, are not known or not defined in their vertical position. - In order to define an area about the
support lines 6 which can be utilized for the handling, thus for the staying and detecting of the wafer, thesystem tolerance region 8 in the vertical direction is determinant, as is shown inFIG. 2 a in cross section. If the maximally possible deflections upwardly 9 and downwardly 10 of the workpiece are taken into consideration, an angle deviating from the horizontal results, theupward angle 9 and thedownward angle 10 with respect tosupport 1, from which subsequently the maximumhandling zone width 11 can be defined, which define thehandling zones handling zones FIG. 2 b. - If the rules as they were previously defined are applied to a
cassette 20 forthin workpieces 7, it is evident that the support zones of theworkpiece 7 are limited to twoparallel zones workpiece 7, as is shown inFIG. 3 a in cross section and in top view inFIG. 3 b. Inconventional wafer cassettes 20 according to the SEMI standard, on each side of the workpiece one additional end support means 14, 15 is disposed which projects into the interior region of thecassette 20. Such inwardly projecting support means 14, 15, shown in dashed lines inFIG. 3 b, cannot be utilized in the present invention. In order to limit or to define the horizontal position of theworkpiece 7 in the cassette, stop means 16, 17 must be provided which only occupy as spots the interior region of the cassette between thesupports handling zones elements cassette 20 has a comb-shapedstructure workpieces 7 in the peripheral region. Thecassette 20 thereby forms a configuration with several receiving slots for the reception ofseveral workpieces 7. It is important that the comb structure has acomb distance 19 large enough to avoid that adjacently insertedworkpieces 7 do not come into contact even in the presence of deflections. If, for example,workpieces 3 are utilized which bend downwardly andworkpieces 2 which are flat, thecomb distance 19 must be greater than the downwardly directeddeflection 3 of theworkpiece 7. Ifworkpieces 7 are utilized, which deflect upwardly as well as downwardly, thecomb distance 19 must be greater than the sum of the maximally expected bending upwardly and downwardly. - To be able to lift and carry the
workpiece 7, carryingelements workpiece 7 is deposited. On the horizontally movable carrying arm of the robot a carrying element mounting 28 is disposed and on this mounting two elongated spaced-apart carryingelements FIG. 5 in top view.FIG. 5 shows the manner in which a disk-shaped workpiece, asemiconductor wafer 7, is deposited on the carryingelements elements adjacent workpieces 7 in the cassette without touching it for the succeeding lifting process or after the deposition of aworkpiece 7 in the cassette. The carryingelements - During the lifting and transporting of
workpiece 7 the carryingelements workpiece 7. Around each of the carryingelements handling zone elements elements cassette 20.FIG. 4 a depicts by example awafer 3 in acassette 20, which is bent downwardly compared to aflat wafer 2, both located in slots of the cassette,. The downwardlybent wafer 3 is to be lifted and removed from the cassette slot with the carryingelements permissible thickness 21 of the carryingelement subjacent wafers FIG. 4 b in detail in the critical margin region. In the region proximal to the comb the greatest possible distance between theadjacent wafers comb distance 19, whose position forms the outer position of the permissiblehandling zone width 23 and the inner limit of the permissiblehandling zone width 23 is spaced somewhat further away from thecomb structure 18 toward the inside, which is limited by thediameter 21 of the carryingelement wafers handling zone width 23, which determine thepermissible handling zones handling zone FIG. 4 b and 4 c. - The definitions for the implementation of the cassette imaging system will be explained in the following in conjunction with
FIG. 6 a to 6 d. Known imaging systems utilize for example reflecting laser systems, in which theread sensor 29 and thereflector 30 are disposed parallel to the wafer surface and oppositely outside of the wafer. Theread sensor 29 is also the source of thelaser scanning beam 31, which extends also parallel to the wafer surface and is reflected in thereflector 30 back onto theread sensor 29. This beam arrangement withscanning beam 31, readsensor 29 andreflector 30 is guided in known manner close to the region of the center line of the wafer plane. If a wafer is moved into the region of thescanning beam 31, the latter is interrupted and the position is detected. This known method is utilized with relatively thick workpieces or semiconductor wafers which are thicker than 0.6 mm. Problems are encountered with thinner wafers if this method is utilized for the detection. If the wafer is thinner than the diameter of thescanning beam 31, yet is still flat, thescanning beam 31 is not interrupted by thewafer 2. If the imaging system is to detect a loaded or an unloaded slot of thecassette 20, it is not possible to detect this reliably with this method, since the center region of thewafer 2 on which detection takes place, may belong, on the one hand, to a wafer bent upwardly 4 or one bent downwardly 3, as is schematically shown in cross section inFIG. 6 a, 6 b and 6 c. - To solve the first problem, according to the invention the
read sensor 32 and the associatedreflector 33 for thin wafers is to be disposed oppositely outside of the plane of thewafer read sensor 32 and thereflector 33 is additionally to be disposed somewhat offset outside of the wafer plane, such that thescanning beam 35 is guided slightly tilted with respect to theplanar wafer plane 2, from which apreferred tilt angle 34 in the range of 0.50 to 2.00 results. - The
small tilt angle 34 of thescanning beam 35 generates a projection of the wafer in the direction of thescanning beam 35 such that a significantlygreater thickness 36, the so-calledapparent thickness 36, seems present than the involved wafer, in fact, has. - The
scanning beam 35 for thinbendable wafers read sensor 32 and thereflector 33 are disposed in the margin region of the wafer periphery, thus in the proximity of thecomb structure cassette 20. Consequently, with a viewing direction in the scanning beam direction not a dot-form beam appears as is conventional in known systems, but rather anapparent thickness 36 ofwafer beam tilt angle 34 as is depicted in detail in cross section inFIG. 6 c. Thescanning beam 34 consequently has the capability of acquiring, apart fromplanar wafers 2, also corresponding upwardly or downwardly deflectedwafers comb structure cassette 20, where thescanning beam 35 is guided, the vertical distance d between an upwardlybent wafer 4 and a downwardlybent wafer 37 within the same slot configuration is less than theapparent thickness 36 which the tiltedscanning beam 35 provides. With the present, known, maximally possible bending degrees of thewafers imaging zone width 38. The one limit results through the tips of thecomb structure bent wafer 4 and a downwardlybent wafer 3 were to intersect if thesewafers comb structure apparent thickness 36 in the region of the tiltedscanning beam 35 must be greater than the maximally possible distance d in the laser beam region from an upwardlybent wafer 4 and between a downwardlybent wafer 3, if these were to lie in the same slot ofcassette 20. As a second condition must be fulfilled that the actual determinedhandling zone width 39 for the measuring system lies within the maximalimaging zone width 38. From thehandling zone width 39, thus determined, result the twoimaging zones comb structures cassette 20, within which thescanning beam 35 can be guided and with theread sensor 32 andreflector 33 located outside of the line. In this way within theimaging zone - The handling of the wafer is conventionally so carried out that it is positioned and deposited on a
flat surface 42 before it is worked in the process station, as is shown in cross section inFIG. 7 a. To enable the system to correctly deposit the wafer on the surface, the original support position is generated as in the cassette with supports, which are referred to thehandling zones wafer 3 rests and which ensure that the distance betweenbase 42 andwafer 3 is large enough to allow carryingelements FIG. 7 a and 7 b. The wafer support posts 54 for this procedure are preferably raised, whereby thewafer 3 is lifted from thebase 42 and, if it is appropriately thin, is also deflected. To attain the lifting ofwafer 3 thewafer base 42 can also be moved in the vertical direction and holding elements other than the so-called wafer support posts 54 can also be utilized for generating the distance between wafer andbase 42. In the retracted state of the carryingarms wafer 3 on the base, the latter lies exclusively in contact in the region of the definedhandling zones FIG. 7 b in conjunction with an example of asemiconductor wafer 7. - Not all wafers are bent along a cylinder axis parallel to the handling zones which are defined by the system. In the least favorable case wafers in a cassette can also be bent such that they are bent parallel to a cylinder perpendicularly to the support line. If such wafers are bent downwardly 44 or upwardly 43 and are placed in a
cassette 20, the actual projection and definition of the form is not very different from those described previously. The determination of thecross section 45 of the carryingelement elements element 47 as an example, in cross section inFIG. 8 d, can also be implemented formed, in order to adapt themselves to thebent wafer 46. In the present example each of the carryingelements 47 is provided with onestep 48 in the peripheral region ofwafer 46 such that thewafer 46 can deflect downwardly in the central region and thereby can adapt to a predetermined desired form, preferably to a planar surface in order to be able to accept essentially the previously made considerations directly. In the margin region further steps can preferably be provided in order to be able to secure the wafer there on the carryingelement 47 in order to avoid during the transport that the wafer becomes displaced during the transport movement. It is also of advantage to fabricate the carryingelement 47 of a material or to coat it with a corresponding material such that a greater surface friction results to decrease the previously described effect. - In a wafer process facility the sole location where the wafer carrying line method is not utilized is the wafer rotation orientation station where wafers are oriented in their planar orientation with respect to a
workpiece marker 7 a. A wafer which has reached this station is conventionally by definition not oriented to thecorresponding marker 7 a. This means that the support axes are randomly oriented with respect to thewafer marker 7 a. The purpose of this station is to bring the wafer into a clearly defined rotation position in order to work it further. This means that the wafer must be rotated. This rotation movement also leads to a rotation of the support lines about the center of the wafer, which means the support lines before and after the orientation are different. To take this into consideration, it is essential that the wafer regions which must be handled are precisely defined in terms of height and in each rotation position of the wafer. To attain this, a circular support base is advantageously realized for the wafer, which is as close as possible to the support lines orimaging zones FIG. 9 b, for this purpose asupport plate 50 is utilized which has a circular support means 51 with a diameter approximating very closely the diameter of the position of theimaging zones orientation 52, the handling system is still capable of lifting the wafer after the orientation. A singlecircular base configuration 51 is especially well suited if cylindrical deformations of the wafer occur. Similar results can be attained if the wafer is borne by a radially disposedbase configuration 53 on thecarrier plate 50 for staying the wafer as is depicted inFIG. 9 a. This configuration can be utilized with advantage if the workpiece overall is not cylindrically bent. - In some vacuum process facilities for working semiconductor wafers two or more robot systems are employed in order to handle the workpieces and to transport them. An important configuration is for example that in which a
first robot 60 is positioned on a facility at atmospheric pressure at the so-called front end, as it is referred to in the semiconductor industry, whereby wafers are transported in and out in cassettes. Thesecond robot 61 can then be positioned in the vacuum process facility, thus under vacuum conditions, in order to transport wafers into the process station and out of the process station. To transport wafers from atmospheric pressure through a lock into a vacuum and back and subsequently wafers fromrobot 60 torobot 61 located within the vacuum chamber, asubstrate transfer station 62 is placed between the tworobots wafers 7 placed by the first robot system onto theposition 63 do not have the correct angular orientation with respect to the second robot system at whichposition 64 would be necessary as is shown inFIGS. 10 a and 10 b. In this case thesubstrate transfer station 62 must be provided withmeans 65 which permit rotating the wafer about the angular difference between the two required wafer positions 63, 64.
Claims (11)
1. Transport mechanism for disk-shaped workpieces (2, 3, 4, 5, 7), in particular for semiconductor wafers, with a controlled, horizontally movable transport arm at whose one end two spaced-apart, elongated carrying elements (26, 27) are disposed for the substantially horizontal reception of the workpiece and that a cassette (20) is provided, which at two opposite sides includes a comb structure (18) for the substantially horizontal reception of several workpieces (7), the carrying elements (26, 27) and the comb structure (18) being implemented such that these elements can be introduced between two adjacent, spaced-apart combs (19) of the comb structure (18) free of contact with the workpieces potentially deposited therein, for lifting or depositing a workpiece (7) with the aid of an additional vertical movement relative with respect to the cassette (20) and the transport arm, characterized in that the carrying elements (26, 27) are disposed such that during the cassette engagement these are essentially each positioned (18) adjacent parallel to the comb structure along a comb and that in this region along and between two adjacent comb planes on one side of the cassette (20) a scanning beam (35) is provided for detecting a workpiece (7) and its position and that the scanning beam (35) is height-positionable relative with respect to the cassette (20), the scanning beam (35) being guided tilted by a small angle (34) with respect to the horizontal workpiece plane.
2. Transport mechanism as claimed in claim 1 , characterized in that for the transport mechanism with transport arm and cassette (20) are defined handling zones (12, 13) within which the carrying elements (26, 27) interact with the surface of the workpiece (7), wherein these elements with respect to the workpiece are determined as two spaced-apart parallel opposing strip-shaped areas, which are oriented substantially parallel to the comb structure (18) when the workpiece is inserted into the cassette (20).
3. Transport mechanism as claimed in claim 2 , characterized in that the width (11) of the handling zones (12, 13) is determined by the sum of the vertical system tolerances (8) of the transport mechanism in combination with the maximal upward and downward bending attained by the workpiece when supported on a line-form support (1) with its bending angles (9, 10) and where these angles intersect with the horizontal planes of the maximum vertical system tolerances.
4. Transport mechanism as claimed in claim 2 , characterized in that the workpiece (7) is a semiconductor wafer and the width of the handling zones is 10 to 20 mm.
5. Transport mechanism as claimed in claim 1 , characterized in that the angle of tilt (34) of the scanning beam (35) is defined such that the beam guided along two adjacent parallel combs (18) the comb distance (19) is not exceeded.
6. Transport mechanism as claimed in claim 1 , characterized in that for the positioning of a workpiece (7) with respect to the cassette (20) a mechanism is provided for the vertical movement of the cassette (20).
7. Transport mechanism as claimed in claim 1 , characterized in that at the one end of the horizontally disposed comb structure (18) at least one stop means (16, 17) is provided for delimiting the end position of the workpiece in the cassette (20), this stop means being disposed outside of the optical path of the scanning beam (35).
8. Transport mechanism as claimed in claim 1 , characterized in that the carrying elements (26, 27) are implemented in the form of rods.
9. Transport mechanism as claimed in claim 1 , characterized in that a second permissible handling zone width (24, 25) is determined, which is smaller than the width of the first handling zone (12, 13) and which is located within this first handling zone determined by the system tolerances, and that this second handling zone width (24, 25) is determined by the cross section dimension (21) of the carrying elements (26, 27) and of the cassette gap width (23) still free at maximally possible resulting deflections of the workpiece (7).
10. Transport mechanism as claimed in claim 1 , characterized in that a further, tilted scanning beam (35′) is provided on the opposite side of the first scanning beam (35) in the proximity of the opposing other comb structure (18) of the cassette (20).
11. Transport mechanism as claimed in claim 1 , characterized in that it comprises at least two transport robots rotatable about the axes (66, 67) with one transport arm (60, 61) each and a rotating mechanism (62) for orienting (65) the handling zones (12, 13) with respect to the transport direction of the transport arms (60, 61) if the transfer position of the workpiece does not lie on the line connecting the two axes (66, 67) of the transport robots.
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US20120308215A1 (en) * | 2011-06-03 | 2012-12-06 | Applied Materials, Inc. | Detection of substrate warping during rapid thermal processing |
CN110729225A (en) * | 2018-07-16 | 2020-01-24 | 台湾积体电路制造股份有限公司 | Wafer handling apparatus and method thereof |
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JP6509103B2 (en) | 2015-12-17 | 2019-05-08 | 東京エレクトロン株式会社 | Substrate processing method, substrate processing apparatus, and substrate processing system |
JP6685445B2 (en) * | 2019-04-01 | 2020-04-22 | 東京エレクトロン株式会社 | Substrate aligning apparatus, substrate processing apparatus, substrate aligning method, substrate processing method |
CN110364461B (en) * | 2019-07-18 | 2021-10-15 | 北京北方华创微电子装备有限公司 | Wafer state detection equipment and method and wafer loading and unloading chamber |
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- 2006-09-15 KR KR1020087012802A patent/KR101341270B1/en active IP Right Grant
- 2006-09-15 WO PCT/CH2006/000498 patent/WO2007056875A1/en active Application Filing
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Also Published As
Publication number | Publication date |
---|---|
EP1952437B1 (en) | 2009-03-25 |
CN101310377A (en) | 2008-11-19 |
WO2007056875A1 (en) | 2007-05-24 |
ATE426917T1 (en) | 2009-04-15 |
US20100316483A1 (en) | 2010-12-16 |
EP1952437A1 (en) | 2008-08-06 |
TWI402934B (en) | 2013-07-21 |
JP2009516376A (en) | 2009-04-16 |
KR20080078810A (en) | 2008-08-28 |
US8491252B2 (en) | 2013-07-23 |
JP5134546B2 (en) | 2013-01-30 |
CN101310377B (en) | 2010-11-17 |
KR101341270B1 (en) | 2013-12-12 |
TW200746351A (en) | 2007-12-16 |
DE502006003294D1 (en) | 2009-05-07 |
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