JP2005347315A - Wafer transfer device and wafer transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer transfer device wherein all wafers housed in a wafer cassette loaded in its hand at the same time, and which can improve the transfer efficiency of the wafer. <P>SOLUTION: A wafer loading part 2 has a lamination structure of engineering plastic and metal. The wafer can be stably held by sucking through suction holes at three places. Thus, no notch is needed, and a clearance among the wafers becomes enough. The wafer loading part 2 can hold 25 pieces of wafers simultaneously, and a hand 1 and a robot arm 13 are connected or separated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wafer transfer apparatus and a wafer transfer method, and more particularly to a wafer transfer apparatus and a wafer transfer method that greatly improve work efficiency by enabling batch handling of the same number of wafers as a wafer cassette.

  As shown in FIG. 6, the conventional wafer transfer apparatus includes a main cassette apparatus 120, an intermediate cassette 130, a handling apparatus 150, a wafer supply cassette 160, and the like which are transferred to an ion implantation apparatus 123 or the like.

  For example, the wafers are transferred from the wafer supply cassette 160 holding 13 unprocessed wafers one by one by the handling device 150 and transferred to the intermediate cassette 130 at the standby position.

Then, after 13 unprocessed wafers are buffered in the intermediate cassette 130, they are collectively transferred to the main cassette apparatus 120.
JP 2002-43395 A

  The conventional wafer transfer apparatus or wafer transfer method shown in FIG. 6A has the following problems.

  First, in the case of a complete single wafer method in which wafers are transferred one by one as shown in FIG. 6A, the wafers are handled one by one from a plurality of stages and transferred to an intermediate cassette 130, and a predetermined number of sheets are buffered. After ringing, the wafer is transferred to the diffusion furnace, and the wafer transfer efficiency is poor.

  Secondly, as shown in FIG. 6B, there is also known a transfer device 170 that can hold a plurality of wafers in a lump. However, in the conventional wafer transfer device, the robot arm portion 173 includes one wafer mounting portion. However, when the wafer size is changed or when the wafer mounting portion needs to be replaced due to a heat treatment process or the like, there is a problem that the working efficiency is greatly reduced.

  The mounting portion 171 on which the wafer is mounted is generally made of a ceramic or glass material. However, when these materials are employed, the mounting portion 171 cannot be made very thin due to its processing, and the processing accuracy cannot be made high, so that the thickness of the mounting portion itself is increased. In addition, in order to prevent the wafer from dropping when scooping up, there is a notch 172 provided at the tip of the wafer mounting portion 171, which limits the number of sheets that can be handled in a lump.

  For example, the ceramic wafer mounting portion 171 is manufactured by a process equivalent to that of a casting, and a predetermined processing accuracy cannot be obtained, and additional processing (thickness adjustment) is performed. For this reason, the delivery time is very long and the cost increases. On the other hand, in the case of the quartz wafer mounting portion 171, the skilled craftsman makes it, so the cost cannot be reduced, and the thickness is limited to, for example, 1.5 mm and the error is about ± 0.5 mm. As described above, when a plurality of wafer mounting portions that cannot obtain a predetermined processing accuracy are stacked, tolerances cannot be absorbed as the number increases.

  When holding a plurality of wafer mounting portions in a lump, 1) not only the processing accuracy of the wafer mounting portion, but also 2) the positioning accuracy of the robot arm, 3) the distortion of the wafer cassette, 4) the wafer mounting portion It is also necessary to consider the assembly accuracy. In other words, as the number of sheets increases, these cumulative tolerances increase, and therefore, in the conventional case, the number of sheets that can be inserted into a wafer cassette as it is by instructing a plurality of wafer mounting portions at once is limited.

  In this case, the clearance from the pitch of the wafer cassette is very small. Specifically, when the pitch of the wafer cassette is 4.7625 mm, the clearance between the wafer cassettes is 1.84 mm in consideration of the above four precisions, and the design and processing of the wafer mounting portion 171 is required within this dimension range. It becomes.

  For example, when the wafer mounting portion 171 is ceramic or quartz and the height of the notch 172 is 0.625 mm, only a clearance of 1.1 mm ± 0.1 is actually secured in consideration of the processing accuracy of the wafer mounting portion 171. Can not. However, in actuality, the wafer mounting portion 171 needs to have a thickness of about 2.0 mm, and if it is made thinner than this, cracks frequently occur. Further, even if the wafer mounting portion 171 made of the above-mentioned material that fits in the clearance can be manufactured, there is a problem that tolerance cannot be sufficiently considered, and the wafer mounting portion breaks by colliding with the wafer cassette.

  The present invention has been made in view of such a problem. First, a hand portion in which a plurality of wafer mounting portions corresponding to each storage portion of a wafer cassette are integrally supported by a support portion, and a hand portion that can be connected to and disconnected from the hand portion. This is solved by providing a robot arm unit.

  Further, the wafer mounting portion is formed by bonding together a first member having a plurality of suction holes provided as a wafer mounting surface and a second member having a plurality of grooves corresponding to the suction holes as a support portion. To do.

  Further, the first member is an engineering plastic.

  Further, each of the wafer mounting portions is characterized in that a tip portion facing the support portion is flat.

  Each of the wafer mounting portions is characterized in that a gap material is disposed in close contact with the support portion.

  In addition, a plurality of the hand portions are provided, and the hand portions are attached to and detached from the robot arm portion and exchanged according to a transfer wafer.

  Second, a wafer cassette having a plurality of stages of wafer storage units is inserted with a hand unit in which the wafer mounting units corresponding to the respective wafer storage units are integrally supported by the support unit, and the wafer is mounted on the wafer mounting unit. A step of holding the wafer by sucking the wafer mounting portion, operating a robot arm connected to the hand portion to transport the wafer to a predetermined position, and a wafer mounted on the hand portion. And the step of transferring to the support board.

  In addition, the wafer mounting portion is a wafer mounting surface, a plurality of suction holes are provided, and a first member and a second member having a plurality of grooves corresponding to the suction holes are bonded to each other. Suction is performed through the hole and the groove.

  According to the present invention, the following effects can be obtained.

  First, since the mounting unit corresponding to each storage unit of the wafer cassette is integrally supported by the hand unit, all the wafers stored in the wafer cassette can be mounted collectively on the hand unit, A wafer transfer apparatus with improved wafer transfer efficiency can be provided.

  Second, the wafer mounting portion is provided with three suction holes and grooves, so that the wafer can be stably sucked and held. Further, since the wafer can be uniformly sucked by the three suction holes and grooves, other wafers can be sucked and supported without lowering the wafer vacuum pressure even if there is a wafer mounting portion on which no wafer is mounted.

  Third, the wafer mounting portion is made of engineering plastic and metal, and can be made inexpensive and thin.

  Fourth, since the wafer can be stably sucked and held, a notch at the front end of the wafer mounting portion for preventing dropping is not required, and the wafer mounting portion can be made thinner. Therefore, since the accumulated tolerance can be reduced, the same number as the number of stages of the wafer cassette can be supported at once.

  Fifth, since the wafer mounting portion is provided with a gap material in the support portion and supports the wafer mounting portions in close contact with each other, leakage of suction air can be prevented.

  Sixth, when exchanging the wafer mounting portion, it is only necessary to replace the hand portion connected to the robot arm portion, and it becomes unnecessary to assemble the wafer mounting portions one by one, and the working efficiency is greatly improved.

  Seventh, all the wafers housed in the wafer cassette can be loaded together in the hand unit, and no buffer is required, so that the wafer transfer efficiency can be improved.

  Eighth, the wafer can be stably conveyed by sucking and holding the wafer at three locations during wafer conveyance.

  An embodiment of the present invention will be described in detail with reference to FIGS.

  With reference to FIG. 1 and FIG. 2, an example of the wafer conveyance apparatus 15 of this embodiment is demonstrated.

  FIG. 1 is a cross-sectional view showing a wafer transfer device, FIG. 1A is an overall view of the wafer transfer device, and FIG. 1B is an enlarged view of a hand unit. FIG. 2 is a plan view of the hand unit shown in FIG.

  As shown in FIG. 1A, the wafer transfer device 15 includes a hand unit 1 and a robot arm unit 13. In the hand unit 1, a plurality of wafer mounting units 2 are integrally supported by a support unit 3.

  The robot arm unit 13 is movable in the horizontal and vertical directions. The robot arm unit 13 can be connected to and disconnected from the hand unit 1. More specifically, the hand portion 1 is provided with a tool portion 6, and the robot arm portion 13 is provided with a master portion 12 at the distal end portion thereof. The tool unit 6 and the master unit 12 can be attached and detached by hydraulic pressure, thereby connecting and disconnecting the hand unit 1 and the robot arm unit 13.

  As shown in FIG. 1B, the hand unit 1 is connected to the robot arm unit 13 so that the plurality of wafer mounting units 2 can be moved in the horizontal, vertical, and straight traveling directions at once.

  The wafer mounting unit 2 individually corresponds to each storage unit of a wafer cassette that stores a wafer to be processed. That is, for example, 25 wafers as many as the wafer cassette storage units are collectively supported by the support unit 3. The above-described tool portion 6 is connected to the support portion 3, and a vacuum air vent hole 5 is provided inside the support portion 3.

  As shown in FIG. 2, the wafer is mounted on the wafer mounting unit 2 as indicated by a broken circle. Three suction holes 23 are provided on the wafer mounting surface made of engineering plastic, and three suction grooves 24 corresponding to the suction holes are provided on the support portion attached to the back surface of the wafer mounting surface. Is communicated with the vent hole 5 inside the support portion 3. In addition, the wafer mounting portion 2 has a flat tip portion facing the support portion 3 (FIG. 1B).

  At the time of wafer transfer, a vacuum connector is connected to the vent hole 5 in the support portion 3 and sucked to suck and support the wafer through the suction groove 24 and the suction hole 23. At this time, since the suction holes 23 are evenly arranged on the main surface of the wafer (dotted circle), the suction is uniform, and the wafer can be stably supported and transported without providing a notch.

  Further, a gap material 4 is disposed on the support portion 3 of each wafer mounting portion 2. The gap material 4 has a resin surface and has a hard core inside, and is embedded in the engineering plastic of the support portion 3.

  Each wafer mounting unit 2 is held at a uniform separation distance by being fixed by the support unit 3. Further, since the gap material disposed around the vent hole 5 is made of resin, the vacuum air can be prevented from leaking and the wafer can be stably sucked and held.

  As described above, in this embodiment, the notch at the tip of the wafer mounting portion 2 is not required, and the wafer mounting portion 2 is formed by adopting strong engineering plastic even if the material of the wafer mounting portion 2 is thin. The thickness can be reduced and the accumulated tolerance can be greatly reduced. Therefore, it is possible to realize a hand portion that supports 25 wafer mounting portions in a lump that can be inserted within the effective dimension of one step of a 25-step wafer cassette.

  Next, the wafer mounting unit 2 will be described with reference to FIG.

  3A is a plan view of the wafer mounting portion 2, FIG. 3B is a cross-sectional view of the wafer mounting portion, and FIG. 3C is a plan view of the support portion.

  The wafer mounting portion 2 is formed by bonding, for example, a metal having a plurality of suction grooves 24 corresponding to the suction holes 23 serving as the support portion 22 and an engineering plastic having the wafer mounting surface 21 and a plurality of suction holes 23. Constructed by bonding with materials. The support part 22 is not limited to metal, but may be engineering plastic or the like.

  Engineering plastics are plastics that are employed in semiconductor manufacturing processes where mechanical properties are strongly required. For example, polycarbonate, polysulfone, polyamide, polyphenylene oxide, and the like are typical resins. Since the dimensional stability at the time of molding is good, it is possible to realize a thin wafer mounting portion 2 that can be inserted and handled at a minute pitch (about 1.84 mm) of the wafer cassette.

  As shown in FIG. 3A, the suction holes 23 are provided at three locations on the wafer mounting surface 21, and the tip of the wafer mounting portion 2 facing the support portion 3 is flat as shown in FIG. Then, three suction grooves 24 are provided in the support portion corresponding to the suction holes as shown in FIG.

  Here, the three suction holes 23 and the suction grooves 24 are described as an example, but the number is not limited to three as long as the suction holes 23 are evenly spaced from the wafer.

  The gap material 4 is embedded and arranged in the support part 3 of the wafer mounting part 2. The outside of the cylindrical core is covered with resin, and the inside of the core is a vent hole 5. Further, since the gap material 4 is compressed and closely contacts the wafer mounting portion 2 in the support portion 3 serving as a vacuum air passage, it is possible to prevent the vacuum air from leaking at a location where the plurality of wafer mounting portions 2 overlap. .

  Further, even if there is a wafer mounting portion 2 on which no wafer is mounted in the hand portion 1, since the suction of each wafer mounting portion 2 is stable, the influence on other wafer mounting portions 2 due to suction variations can be suppressed.

  As described above, the material constituting the wafer mounting portion 2 is made of engineering plastic with high processing accuracy and high strength, and the wafer is formed by flattening the tip without providing the notch previously provided for preventing the wafer from falling. The thickness of the mounting portion 2 can be 1.5 mm ± 0.01, which can be significantly thinner than the conventional notched wafer mounting portion (2.0 mm).

  In this way, by using engineering plastics for each wafer mounting portion 2 to make it thin and supporting it by the support portion 3 in a batch, the processing accuracy of the wafer mounting portion 2 and the assembly accuracy of the wafer mounting portion can be improved. And the cumulative tolerance can be greatly reduced. Therefore, even if the 25 wafer mounting portions 2 are supported together, they can be accommodated within the effective dimension range (1.84 mm) of the pitch of the wafer cassette.

  Next, a case where the hand unit is replaced will be described with reference to FIG. In addition, although demonstrated in the simplified figure in FIG. 4, the hand part 1 shall support the 25 wafer mounting parts 2 shown in FIG. 1 collectively.

  The wafer mounting unit 2 corresponds to the size of the wafer to be processed, and it is necessary to replace the wafer mounting unit 2 when changing the wafer size. Even if the wafer size is the same, the p-type semiconductor and the n-type semiconductor may need to be replaced in order to prevent contamination due to the heat treatment process.

  In such a case, the present embodiment has a plurality of hand units 1 corresponding to wafers having different wafer sizes and heat treatment processes, and the hand unit 1 can be attached to and detached from the robot arm unit 13 according to the wafer to be transferred. it can. That is, the 25 wafer mounting portions 2 can be exchanged at once.

  The alignment hole 36 provided in the tool unit 6 of the hand unit 1 is inserted into the aligner 35 (FIG. 4A), and the robot arm unit 13 and the hand unit 1 are separated (FIG. 4B).

  Similarly, the hand unit 1 to be exchanged is also in a standby state in which the hand unit 1 is inserted into the aligner 35, and the robot arm unit 13 is aligned with the hand unit 1 (FIG. 4C). After the alignment is completed, the robot arm unit 13 and the hand unit 1 are connected, and the hand unit 1 is exchanged (FIG. 4D).

  In the case of a conventional apparatus that can handle five sheets at a time, when replacing wafers and hand parts, the wafer mounting parts are assembled one by one in the robot arm part, which is very complicated. Further, it is necessary to ensure the assembly accuracy, and the accumulated tolerance increases, so that it is impossible to assemble five or more sheets. However, according to this embodiment, it is only necessary to replace the hand unit 1 on which the wafer mounting unit 2 is collectively supported, and there is no need to consider assembly accuracy. As a result, the accumulated tolerance can be reduced, and 25 sheets can be handled collectively. Furthermore, wafer exchange and hand part exchange are facilitated, and throughput can be improved.

  Next, a wafer transfer method will be described with reference to FIG.

  In the wafer transfer method of the present invention, a wafer cassette having a plurality of stages of wafer storage units is inserted with a hand unit in which the same number of wafer mounting units as the wafer cassette are integrally supported by the support unit, and the wafer is inserted into the wafer mounting unit. The process of mounting, the process of holding the wafer by sucking the wafer mounting part, operating the robot arm connected to the hand part and transporting the wafer to a predetermined position, and the wafer mounted on the hand part to the support board And a transferring process.

  In addition, although demonstrated in the simplified figure in FIG. 5, the hand part 1 shall support the 25 wafer mounting parts 2 shown in FIG. 1 collectively.

  First step (FIG. 5A): A wafer cassette having a plurality of stages of wafer storage units is inserted with a hand unit in which a wafer mounting unit equal in number to the wafer cassette is integrally supported by a support unit. The process of mounting on the mounting part.

  The wafer cassette 30 has a 25-stage wafer storage section 34, and the wafer 31 is stored in each stage. However, there may be a stage where no wafer is stored. The wafer cassette 30 is provided with the respective wafer storage portions 34 at a pitch of 4.7625 mm, for example. The thickness of the wafer 31 is 650 μm.

  As described above, the hand unit 1 has the same number of 25 wafer mounting portions 2 as the number of stages of the wafer cassettes 30. Each wafer mounting portion 2 is spaced evenly with the gap material in close contact with the support portion. Is held in. The thickness of the wafer mounting portion 2 is 1.5 mm ± 0.01.

  Then, the wafer mounting portion of the hand unit 1 is aligned so as to correspond to each stage of the wafer cassette 30 and inserted into the wafer cassette 30. At this time, considering the injection molding accuracy of the wafer cassette 30, the verticality from the bottom surface of the wafer cassette, the molding accuracy of the wafer mounting portion thickness, the positioning accuracy of the robot, etc., in the example of this embodiment, the clearance of 3.34 mm is 1 A wafer mounting portion 2 of 5 mm is inserted. (FIG. 5A).

When the wafer insertion position is determined, the robot arm 13 is raised and the wafer 31 is scooped up to the wafer mounting unit 2. That is, in consideration of the above accuracy, the wafer and the wafer mounting unit 2 are operated in an absolute space of 1.84 mm. In this embodiment, the wafer mounting unit 2 is thinned to 1.5 mm. The vertical movement amount is 0.34 mm (FIG. 5B).
Second step (FIG. 5C): a step of holding the wafer by sucking the wafer mounting portion and operating the robot arm connected to the hand portion to transport the wafer to a predetermined position.

  As described above, the wafer mounting portion 2 is configured by bonding a metal portion to a wafer mounting surface made of engineering plastic. The wafer mounting surface is provided with three suction holes provided, and the metal part is provided with suction grooves corresponding to the suction holes. The suction groove extends to the support portion.

  At the time of wafer conveyance, the wafer is sucked and supported through the suction grooves and the suction holes by connecting a vacuum connector to the air hole inside the support portion and sucking it. The suction conditions are, for example, in the range of −20 kPa to −40 kPa.

Thus, the three suction holes on the wafer mounting surface are arranged so as to be evenly distributed on the wafer main surface. Three suction grooves correspond to the suction holes, that is, the wafer is sucked evenly on the main surface and stably held on the wafer mounting portion,
In addition, a gap material is disposed on the support portion of each wafer mounting portion. The gap material has a resin surface and a hard core inside. Each wafer mounting portion is supported in close contact with the gap material and maintains a uniform separation distance. Further, since the vacuum air can be prevented from leaking by the resin on the surface of the gap material, the wafer can be stably sucked and held.

  Therefore, in this embodiment, it is possible to prevent the robot arm unit from dropping due to the movement of the robot arm unit without providing a notch at the tip of the wafer transfer unit.

  Then, the wafer is transferred by moving the robot arm unit to a predetermined position.

  Third step (FIG. 5D): a step of transferring the wafer mounted on the hand unit to the support board.

  The wafer 31 is transferred to the target support board 32. The support board is made of, for example, quartz or SiC, and is a long board 32 provided with a number of grooves 33 for evenly arranging the wafers 31. The position of the hand unit 1 (wafer mounting unit 2) is determined in accordance with each groove 33, and the wafer 31 is transferred to the groove 33.

As described above, according to the present embodiment, since the same number of 25 wafers as the wafer cassette can be handled at once, the throughput can be greatly improved.

It is sectional drawing which shows the wafer conveyance apparatus of this invention. It is a top view which shows the wafer conveyance apparatus of this invention. It is a top view which shows the wafer conveyance apparatus of this invention. It is a top view which shows the wafer conveyance apparatus of this invention. It is sectional drawing which shows the wafer conveyance method of this invention. It is sectional drawing which shows the conventional wafer conveyance apparatus and the conveyance method.

Explanation of symbols

1 Hand part
DESCRIPTION OF SYMBOLS 2 Wafer mounting part 3 Support part 4 Gap material 5 Vent hole 6 Tool part 12 Master part 13 Robot arm part 15 Wafer transfer device 21 Wafer mounting surface 22 Support part 23 Adsorption hole 24 Adsorption groove 30 Wafer cassette 31 Wafer 32 Support board 33 Groove 34 Wafer storage section 35 Aligner 36 Alignment hole 120 Main cassette apparatus 123 Ion implantation apparatus 130 Intermediate cassette 150 Handling apparatus 160 Wafer supply cassette

Claims (8)

A hand portion in which a plurality of wafer mounting portions corresponding to the respective storage portions of the wafer cassette are integrally supported by the support portion;
A wafer transfer apparatus comprising: a robot arm part connectable to and detachable from the hand part.   The wafer mounting portion is formed by bonding together a first member having a wafer mounting surface and a plurality of suction holes and a second member having a plurality of grooves corresponding to the suction holes as a support portion. Item 2. The wafer conveyance device according to Item 1.   The wafer transfer apparatus according to claim 1, wherein the first member is an engineering plastic.   The wafer transfer apparatus according to claim 1, wherein each of the wafer mounting portions has a flat tip portion facing the support portion.   2. The wafer transfer apparatus according to claim 1, wherein each of the wafer mounting portions is arranged such that a gap material is in close contact with the support portion.   2. The wafer transfer apparatus according to claim 1, comprising a plurality of the hand units, wherein the hand units are attached to and detached from the robot arm unit in accordance with a transfer wafer. Inserting a wafer unit having a plurality of wafer storage units into which a wafer mounting unit corresponding to each of the wafer storage units is integrally supported by a support unit, and mounting the wafer on the wafer mounting unit;
Holding the wafer by sucking the wafer mounting unit, operating a robot arm connected to the hand unit to transport the wafer to a predetermined position;
Transferring the wafer mounted on the hand part to a support board;
A wafer transfer method comprising: The wafer mounting portion is a wafer mounting surface and is provided with a plurality of suction holes, and a first member and a second member having a plurality of grooves corresponding to the suction holes are bonded together. The wafer transfer method according to claim 7, wherein suction is performed through the groove.

Images