Wafer processing apparatus

Abstract

To provide a cassette chamber capable of simplifying the structure of a dummy cassette.SOLUTION: A cassette chamber for a semiconductor wafer processor is provided with an elevator 22 which can be moved up and down in the chamber, an upper surface 31 which is provided on the upper part of the elevator 22 and on which a cassette 23 to be processed can be placed, and a cassette base 21 having a housing space for housing a dummy cassette 24.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wafer processing apparatus that uses a wafer cassette used to move multiple wafers between processing apparatuses when performing various processes on semiconductor wafers, and more particularly to a wafer processing apparatus that uses dummy wafers for dummy processing and cleaning processing. [Background technology]

[0002] A cluster-type wafer processing system is known, consisting of multiple processing chambers for wafer processing such as plasma processing, a transfer chamber (robot hand chamber) for transferring wafers into and out of the processing chambers, and a cassette chamber connected to the transfer chamber. Outside the cassette chamber, multiple wafers to be processed are stored in a container called a wafer cassette, which has multiple vertical storage levels. For example, for wafers smaller than 6 inches, the levels are spaced 5 mm or less apart. Once the wafer cassette is loaded into the cassette chamber, a robot hand in the transfer chamber removes wafers one by one from the wafer cassette and sends them to the appropriate processing chamber. After processing, the robot hand removes the wafers from the processing chamber and stores them in the appropriate level of the processed wafer cassette or the original wafer cassette.

[0003] The cassette chamber is provided with an elevator mechanism (elevator) that raises and lowers the wafer cassette, and when the robot hand takes out (or stores) a wafer to be processed, the elevator is driven so that the storage level of the wafer cassette that stores (or should store) that wafer is at the height of a predetermined gate connecting the cassette chamber and the transfer chamber. In this case, taking into account the spacing between the storage levels, the thickness of the wafer, and the thickness of the robot hand, when the robot hand takes out (or stores) a wafer to be processed, it is required that the processing cassette be driven with a repeatability accuracy of 1 mm or less.

[0004] In each processing chamber, after starting up the equipment, dummy processing is performed to confirm that the processing conditions have stabilized. Furthermore, a cleaning process is performed to stabilize the conditions after processing is completed. In these cases, dummy wafers are used. However, since the number of wafers that can be processed is reduced if dummy wafers are mixed in the same cassette as the wafers to be processed, the dummy wafers are stored in a dummy cassette separate from the wafers to be processed. Dummy cassettes typically store fewer dummy wafers than wafer cassettes that store the wafers to be processed (hereinafter referred to as "processed wafer cassettes"), and therefore are shorter in height than the processed wafer cassettes.

[0005] Wafer cassettes are placed on the top of the elevator inside the cassette room, but when a dummy cassette is used, the dummy cassette is usually placed on the top of the elevator first, and then the cassette to be processed is placed directly on top of the dummy cassette (Patent Document 1, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 07-201951 [Patent Document 2] Japanese Patent Application Publication No. 11-111810 Summary of the Invention [Problem to be solved by the invention]

[0007] In order for the robot hand to correctly pick up the target wafer from the processing cassette, the elevator must be able to vertically position the wafer with a repeatability accuracy of 1 mm or less. If the processing cassette is placed directly on top of the dummy cassette, it is difficult to achieve such vertical positioning accuracy for the processing cassette. Furthermore, since a single processing cassette typically holds approximately 25 processing wafers, the total weight is quite large. If such a processing cassette is placed directly on top and moved up and down at high speed by the elevator, the dummy cassette must be constructed to be sturdy enough to withstand such acceleration (deceleration). These factors complicate the structure of the dummy cassette, which is essentially required to be simple.

[0008] Furthermore, while semiconductor device manufacturers (device manufacturers) independently design and use wafer cassettes to store wafers to be processed that correspond to the devices and production lines they produce, dummy cassettes are typically designed and manufactured by semiconductor manufacturing equipment manufacturers as accessories to semiconductor wafer processing equipment. Because dummy cassettes store dummy wafers used in processes (known as cleaning and seasoning processes) to maintain the performance of semiconductor wafer processing equipment, they are typically delivered to semiconductor manufacturing equipment manufacturers. As a result, wafer cassettes come in a variety of specifications depending on the wafers used by device manufacturers, and their undersides also vary in shape. While adjustable fixing devices are installed on the top of the elevator in the transfer chamber to accommodate the undersides of these various shaped wafer cassettes, when using dummy cassettes, semiconductor manufacturing equipment manufacturers must either prepare cassettes with various shapes so that their tops can accommodate the underside shapes of various wafer cassettes, or install fixing devices that can accommodate the various underside shapes, similar to the elevator tops. However, this increases the variety of dummy cassettes, resulting in increased costs and management issues.

[0009] The problem to be solved by the present invention is to provide a cassette chamber that uses a cassette system for dummy wafers so as to improve the handling of dummy wafers, simplifies the operation and structure of dummy cassettes, and allows the use of existing wafer cassettes to be the same as before. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a cassette chamber for a semiconductor wafer processing apparatus, which comprises: An elevator that can go up and down inside the cassette room, a cassette stand provided on the upper part of the elevator and having an upper surface on which a cassette to be processed can be placed and a storage space for storing a dummy cassette; The present invention is characterized by comprising:

[0011] In the cassette chamber for the semiconductor wafer processing system according to the present invention, the dummy cassette is not placed directly below the processed cassette, but is stored in a storage space inside the cassette table installed at the top of the elevator. Meanwhile, the processed cassette is placed on the top surface of the cassette table. Therefore, the dummy cassette does not need to support the weight of the processed cassette, and since it is always placed on the same fixed surface, installation reproducibility is ensured, and the possibility of transport errors for cassettes with small pitches is reduced.

[0012] Furthermore, since various types of wafer cassettes are placed on the top surface of the cassette table, the dummy cassettes are exempted from the role of directly supporting the wafer cassettes on top of them, and can be designed with only the shape required for a dummy cassette, eliminating the need to redesign the dummy cassettes every time the wafer cassette to be processed is changed. As a result, the number of types of dummy cassettes can be kept to a minimum, reducing costs.

[0013] In the cassette chamber for the semiconductor wafer processing apparatus according to the present invention, it is desirable that the insertion / removal opening for the dummy cassette be provided on the upper surface of the cassette table.

[0014] As described in Patent Documents 1 and 2, cluster-type wafer processing apparatuses often have multiple wafer processing apparatuses and multiple cassette chambers arranged around a transfer chamber. When multiple (usually two) cassette chambers are arranged around a single transfer chamber, the gates connecting the transfer chamber to each cassette chamber are positioned at a predetermined angle (e.g., 60 degrees) relative to the center of rotation of a robot hand installed in the transfer chamber. Meanwhile, considering the handling of the cassettes, it is desirable that the doors used to store and remove cassettes from the cassette chambers be parallel to each other so that cassettes can be removed from both cassette chambers in the same direction. In this arrangement, the direction of removal of dummy wafers from a dummy cassette (the direction of the gate) and the direction of removal of the dummy cassette itself from the cassette chamber are not directly opposite each other (180 degrees) but are oblique. It is somewhat difficult for an operator to insert and fix the dummy cassette directly through the other door so that the dummy wafer removal opening is aligned with the diagonal gate direction, and it is also difficult to visually check.

[0015] In contrast, by providing the insertion / removal opening for the dummy cassette on the top surface of the cassette table as described above, the dummy cassette can be easily stored and placed inside the cassette table so that the removal opening for the dummy wafers is aligned with the diagonal gate direction.

[0016] In the cassette chamber for the semiconductor wafer processing apparatus according to the present invention, it is desirable to provide a cassette positioning device for determining the position of the cassette to be processed on the loading section, which is a location other than the storage / removal port for the dummy cassette on the top surface of the cassette table. This makes it possible to easily determine the position of the cassette to be processed at the top of the elevator, and also makes it easy and reliable to take out / store wafers to be processed from the cassette to be processed in the cassette chamber.

[0017] It is desirable that the cassette positioning device be capable of changing its position within the placement section, thereby making it possible to accommodate various manufacturers and types of cassettes to be processed. [Effects of the Invention]

[0018] In the cassette chamber according to the present invention, the dummy cassette does not need to support the weight of the cassette to be processed, and the dummy cassette itself does not need to have high strength.

[0019] Since the top surface of the cassette table is responsible for placing various types of cassettes to be processed, the dummy cassettes are exempt from this role and can be designed with only the necessary shape for a dummy cassette. As a result, the number of types of dummy cassettes can be kept to a minimum, thereby reducing costs. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a plan view of the entire semiconductor wafer processing apparatus in which a cassette chamber according to an embodiment of the present invention is used; [Figure 2] FIG. 4 is a vertical cross-sectional view of the inside of the cassette chamber. [Figure 3] FIG. [Figure 4] FIG. 2 is a side view of a cassette stand and a cassette to be processed placed thereon. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] A cassette chamber according to one embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a plan view of a semiconductor wafer processing apparatus 11 in which the cassette chamber of this embodiment is used. This semiconductor wafer processing apparatus 11 is equipped with three wafer processing chambers, each of which performs a desired process on a single semiconductor wafer, such as plasma etching, plasma film formation, or plasma cleaning. The semiconductor wafer processing apparatus 11 also has two cassette chambers, 13a and 13b. Of these cassette chambers, cassette chamber 13a stores wafers before processing in the wafer processing chamber, while cassette chamber 13b stores wafers after processing. Note that wafers processed in the wafer processing chamber may be stored back in the original cassette chamber. These three wafer processing chambers 12a, 12b, 12c and two cassette chambers 13a, 13b are arranged in a circle around one handling chamber 14, and a transfer arm 15 in the handling chamber 14 allows the wafers to be processed (and dummy wafers, described below) 16 to be transferred sequentially between them.

[0022] The two cassette chambers 13a, 13b have almost the same structure but are symmetrical. A longitudinal cross-sectional view of the interior of cassette chamber 13a is shown in Fig. 2, and a transverse cross-sectional view is shown in Fig. 3. As shown in Fig. 2, inside cassette chamber 13a, a cassette table 21 is moved up and down by an elevator 22. A processed cassette 23 is placed on the top surface of cassette table 21, and a dummy cassette 24 is stored inside cassette table 21. Since the inside of cassette chamber 13a is evacuated during wafer processing, a lock door 26 is provided on the side facing the handling chamber 14, which allows transfer arm 15 to load / unload wafers 16 from the processed cassette 23 (or dummy cassette 24), and a loading door 27 is provided on the opposite side, which allows loading / unloading of the processed cassette 23 and dummy cassette 24 into / from the cassette chamber 13a. As shown in Figure 1, the lock doors 26a, 26b of the two cassette chambers 13a, 13b are arranged at an angle centered on the handling chamber 14, while the loading doors 27a, 27b are parallel (side-by-side), so that the cassettes 23 to be processed and the dummy cassettes 24 can be loaded / unloaded from these loading doors 27a, 27b.

[0023] In addition, a wafer detection sensor consisting of a light emitter 25a and a light receiver 25b is provided on the side wall of the cassette chamber 13a to detect whether or not a wafer is present in each stage of the cassette 23 for processing (and the dummy cassette 24).

[0024] 4 shows a side view of the cassette table 21 and the processed wafer cassette 23 placed thereon. The dummy cassette 24 is stored inside the cassette table 21 (storage space), and its upper surface is configured to be slightly lower than the loading surface 31, which is the upper surface of the cassette table 21. The processed wafer cassette 23 is placed on the loading surface 31 of the cassette table 21 so as not to come into direct contact with the dummy cassette 24. The dummy cassette 24 stores approximately five dummy wafers 32, and the processed wafer cassette 23 stores 25 processed wafers 33. The dummy cassette 24 is provided with a pair of handles 29 to make it easy to store it in and remove it from the cassette table 21.

[0025] A plan view of the cassette table 21 is shown in FIG. 5, and a bottom view is shown in FIG. 6. The bottom surface of the cassette table 21 preferably has a high degree of flatness because it is in close contact with the elevator. A plan view of the dummy cassette 24 is shown in FIG. 7, and a bottom view is shown in FIG. 8. The bottom surface of the dummy cassette 24 preferably has a high degree of flatness because it is the surface on which the internal bottom surface 42 of the cassette table 21 is placed. A rectangular hole 41 slightly larger than the planar shape of the dummy cassette 24 is provided in the placement surface 31 of the cassette table 21, and the dummy cassette 24 is placed into the cassette table 21 from above through this hole 41. The internal bottom surface 42 of the cassette table 21 (the surface on which the dummy cassette 24 is placed) has four corner blocks 43 for determining the position of the dummy cassette 24, and the position of the placed dummy cassette 24 on the internal bottom surface 42 of the cassette table 21 is determined by these four corner blocks 43.

[0026] The mounting surface 31 of the cassette table 21 is also provided with four corner blocks 44 (naturally, at locations other than the holes 41) for determining the position of the cassette to be processed within the mounting surface 31. These four corner blocks 44 are normally fixed, and the cassette to be processed 23 is inserted from above into the frame formed by the four corner blocks 44 and placed on the mounting surface 31. These four corner blocks 44 are fixed to the mounting surface 31 with two screws, but the mounting surface 31 is provided with screw holes corresponding to these screws at various positions, allowing various types of cassettes to be fixed. [Explanation of symbols]

[0027] 11...Semiconductor wafer processing device 12a, 12b, 12c...wafer processing chambers 13a, 13b...Cassette chamber 14...Handling room 15...Transport arm 16...Wafer 21...Cassette stand 22...Elevator 23...Cassette for processed material 24...Dummy cassette 25a...Light emitter 25b…Receiver 26, 26a...Locked door 27, 27a...Loading door 29...Handle 31...Placement surface 32...Dummy wafer 33... Wafer to be processed 41...hole 42...Bottom 43, 44...Corner blocks

Claims

1. An elevator that can go up and down the room, a cassette stand provided on the upper part of the elevator and having an upper surface on which a cassette to be processed can be placed and a storage space for storing a dummy cassette; A cassette chamber for a semiconductor wafer processing apparatus, comprising:

2. 2. A cassette chamber for a semiconductor wafer processing apparatus according to claim 1, wherein said cassette table has an opening for inserting / removing said dummy cassette on said upper surface.

3. 3. A cassette chamber for a semiconductor wafer processing apparatus according to claim 2, further comprising a cassette positioning device for determining the position of the cassette to be processed within the upper surface, on a placement portion other than the insertion / removal opening on the upper surface.

4. 4. A cassette chamber for a semiconductor wafer processing apparatus according to claim 3, wherein the cassette positioning device is capable of changing its position within the placement section.

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