Work placement table

Abstract

To provide a workpiece mounting table that can detect the presence of a wide variety of workpieces.SOLUTION: A workpiece mounting table 1 comprises a tray 2, a support mechanism 3, and a control unit 4. The support mechanism 3 includes a support member 31 that supports a workpiece W, a connecting member 32 that is interposed between the support member 31 and the tray 2 and is elastically deformable according to the weight of the workpiece W, a detected object 33 that moves following the elastic deformation of the connecting member 32, and a proximity sensor 34 that detects approach of the detected object 33 to a predetermined distance, and is provided so as to be movable in the radial direction of the tray 2. When the proximity sensor 34 detects the approach of the detected object 33, the control unit 4 determines that the workpiece W is placed on the tray 2 and the support member 31.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a work placement table for placing a work piece.

Background Art

[0002] Conventionally, in manufacturing apparatuses for work pieces such as semiconductor wafers, when transferring a work piece between apparatuses, a configuration in which the work piece is temporarily placed on a work placement table is known.

[0003] For example, Patent Document 1 discloses a wafer polishing apparatus 1 including wafer transfer tables 431 and 432 for temporarily placing a wafer 10 when transferring the wafer 10 between a load / unload unit 3 and a polishing head 42. Note that the reference numerals are those in Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, a work placement table is provided with a presence sensor for determining whether or not a work piece is placed thereon. As such a presence sensor, a reflection type or a transmission type is generally used.

[0006] As shown in FIGS. 5(a) and 5(b), when detecting the presence of a work piece 100 with a reflection type presence sensor, a pair of fiber sensors 102 and 103 are provided on a tray 101, and light irradiated from one fiber sensor 102 is reflected by the work piece 100, and this reflected light is received by the other fiber sensor 103. When the received light amount exceeds a predetermined threshold value, it is detected that the work piece 100 is placed on the tray 101.

[0007] On the other hand, as shown in FIG. 5(c), when the workpiece 100 is not placed on the tray 101, since the amount of received light of the fiber sensor 103 does not exceed a predetermined threshold value, it is determined that the workpiece 100 is not placed on the tray 101.

[0008] Also, as shown in FIGS. 6(a) and 6(b), when detecting the arrival of the workpiece 100 with a transmissive arrival sensor, an illumination 106 that irradiates light toward the fiber sensor 105 provided on the tray 104 is arranged. When the light irradiated from the illumination 106 is blocked by the workpiece W and the amount of received light falls below a predetermined threshold value, it is detected that the workpiece 100 is placed on the tray 104.

[0009] On the other hand, as shown in FIG. 6(c), when the workpiece 100 is not placed on the tray 104, since the amount of received light of the fiber sensor 105 exceeds a predetermined threshold value, it is determined that the workpiece 100 is not placed on the tray 104.

[0010] However, when using the reflective arrival sensor as described above, if the workpiece 100 has a matte surface or a chemical solution such as water or slurry adheres to the workpiece 100 and the reflected light reflected by the workpiece 100 is diffusely reflected, the reflected light does not return to the fiber sensor 103. Also, as shown in FIG. 5(d), if the space between the workpiece 100 and the fiber sensor 102 is filled with water, the light passes through the workpiece 100 without being reflected at the interface, and there is a problem that the arrival of the workpiece cannot be detected even though the workpiece 100 is placed on the tray 101.

[0011] Also, when using a transmissive arrival sensor, for a workpiece 100 having transparency, the light irradiated from the illumination 106 passes through the workpiece 100. Also, as shown in FIG. 6(d), if the space between the workpiece 100 and the fiber sensor 105 is filled with water, the amount of transmitted light increases, and there is a problem that the arrival of the workpiece cannot be detected even though the workpiece 100 is placed on the tray 104.

[0012] Therefore, technical problems to be solved arise in order to cope with the detection of the inventory of various workpieces, and an object of the present invention is to solve this problem.

Means for Solving the Problem

[0013] In order to achieve the above object, a workpiece mounting table according to the present invention is a workpiece mounting table provided with inventory detection means for detecting that a workpiece is placed on a tray, wherein the inventory detection means includes a support member for supporting the workpiece, and a connection member interposed between the support member and the tray and capable of elastic deformation according to the self-weight of the workpiece, on the tray a detected body that moves following the elastic deformation of the connection member, and a proximity sensor that detects that the detected body has approached a predetermined distance, a support mechanism provided movably in the radial direction of the tray, and a control unit that determines that the workpiece is placed on the tray and the support member when the proximity sensor detects the approach of the detected body.

[0014] According to this configuration, when the workpiece is placed on the support member, the connection member elastically deforms downward due to the self-weight of the workpiece, so that the proximity sensor detects the approach of the detected body. Therefore, regardless of the type of the workpiece and the usage environment of the tray, the inventory of the workpiece can be detected according to the self-weight of the workpiece. Furthermore, by configuring the support mechanism to be movable in the radial direction of the tray according to the outer diameter of the workpiece, workpieces with different diameters can be accommodated.

[0015] Also, in the workpiece mounting table according to the present invention, it is preferable that the proximity sensor is embedded on the opposite side of the detected body with the tray interposed therebetween.

[0016] According to this configuration, deterioration and failure of the proximity sensor caused by adhesion of water or chemicals can be suppressed.

[0017] Also, in the workpiece mounting table according to the present invention, it is preferable that the connection member is a leaf spring having a base end fixed to the tray and a support member provided at the tip end.

[0018] According to this configuration, since the amount of elastic deformation of the leaf spring according to the weight of the workpiece can be easily adjusted, the amount of movement of the object to be detected can be appropriately set according to the weight of the workpiece.

[0019] Further, in the workpiece mounting table according to the present invention, it is preferable that the support surface of the support member that contacts the workpiece is formed to be convexly curved upward.

[0020] According to this configuration, since the support member contacts the workpiece with a reduced area, damage to the workpiece can be suppressed.

Advantages of the Invention

[0021] In the present invention, when the workpiece is placed on the support member, the connecting member is elastically deformed downward by the weight of the workpiece, and the proximity sensor detects the approach of the object to be detected. Therefore, regardless of the type of the workpiece and the usage environment of the tray, the presence of the workpiece can be detected according to the weight of the workpiece.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0023] Embodiments of the present invention will be described with reference to the drawings. In the following, when referring to the number of components, numerical values, amounts, ranges, etc., unless otherwise specified or limited to a specific number in principle, it is not limited to that specific number, and it may be more or less than the specific number.

[0024] Also, when referring to the shape, positional relationship, etc. of components, etc., unless otherwise specified or it is considered otherwise in principle, it includes those that are substantially approximated or similar to the shape, etc.

[0025] Also, the drawings may be exaggerated, such as by enlarging characteristic parts for easy understanding of the characteristics, and the dimensional ratios of components, etc. are not necessarily the same as the actual ones. Also, in cross-sectional views, in order to make the cross-sectional structure of components easy to understand, the hatching of some components may be omitted.

[0026] FIG. 1 is a perspective view schematically showing a work placement table 1 according to a first embodiment of the present invention. The work placement table 1 is for temporarily placing a work when transferring the work in a semiconductor manufacturing apparatus, and is, for example, a work transfer table provided between a transfer robot and a polishing apparatus, or a work receiving table used when transferring a work between a plurality of transfer robots.

[0027] The work placement table 1 includes a tray 2 and a support mechanism 3. The tray 2 is made of a resin material that can be detected when the detected object 33 approaches the proximity sensor 34, and is formed in a disk shape. On the surface side of the tray 2, three receiving portions 21 for receiving the back peripheral edge of the work W are provided.

[0028] The support mechanism 3 detects the presence of the work W by the weight of the work W. The support mechanism 3 and the three receiving portions 21 are arranged concentrically and equidistantly from each other when viewed from a plane. The support mechanism 3 includes a support member 31, a connecting member 32, a detected object 33, and a proximity sensor 34.

[0029] The support member 31 is provided at the tip of the connecting member 32 and supports the peripheral edge of the back surface of the workpiece W. The support surface 31a of the support member 31 is formed to be convexly curved upward. Thereby, the support member 31 can support the workpiece W with a reduced area. The support member 31 is made of resin, and it is preferably one that has particularly low dust generation property and exhibits chemical resistance. For example, polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), etc. are considered.

[0030] The connecting member 32 has its proximal end side joined to the tray 2. Specifically, with the proximal end side of the connecting member 32 held by a pair of upper and lower gripping portions 22 provided on the outer periphery of the tray 2, the gripping portions 22 and the connecting member 32 are fastened with bolts 35, whereby the connecting member 32 is integrated with the tray 2. A chevron-shaped space A is formed in the pair of gripping portions 22.

[0031] The connecting member 32 is made of metal or resin, and it is preferably one that exhibits chemical resistance and is difficult to swell. For example, PTFE, PEEK, PPS, etc. are considered. The connecting member 32 is configured to elastically deform appropriately according to the weight of the workpiece W. Thereby, when the workpiece W is placed on the support member 31, the connecting member 32 elastically deforms so as to bend downward around the portion held by the gripping portion 22 within the space A.

[0032] For example, for a workpiece W of about several grams, it is conceivable to set the thickness of the connecting member 32 to about 0.2 mm. In order to ensure the followability of the connecting member 32, the thickness of a single connecting member 32 is preferably about 0.2 to 0.4 mm. If the thickness is more than that, the rigidity increases excessively and it becomes difficult to deform due to the self-weight of the workpiece W. Therefore, when changing the spring constant of the connecting member according to a relatively heavy workpiece W, it is preferable to configure it such that a plurality of thin connecting members 32 are stacked rather than applying a single thick connecting member 32.

[0033] The detected object 33 is provided on the opposite side of the support member 31 with the connection member 32 interposed therebetween. Further, the detected object 33 is fixed to the tip of the connection member 32 and is configured to be vertically movable integrally with the connection member 32 according to the self-weight of the workpiece W. The detected object 33 is a metal body that can be detected by the proximity sensor 34. The detected object 33 is preferably a rust-resistant metal such as stainless steel. Further, in order to suppress the elution of metal ions, the surface of the detected object 33 may be coated with Teflon.

[0034] The proximity sensor 34 is embedded in the tray 2 below the detected object 33. Specifically, the proximity sensor 34 is provided at a position where it can detect the detected object 33 when the connection member 32 is elastically deformed to the lower limit by the self-weight of the workpiece W. Note that the detection range of the proximity sensor 34 can be arbitrarily changed with a rotary adjustment trimmer or the like. The proximity sensor 34 is embedded on the back side of the tray 2, and it is possible to suppress deterioration and failure of the proximity sensor 34 caused by the adhesion of water and chemicals. When the proximity sensor 34 detects the approach of the detected object 33, it sends a detection signal to the control unit 4.

[0035] The operation of the workpiece mounting table 1 is controlled by the control unit 4. The control unit 4 controls each component constituting the workpiece mounting table 1. The control unit 4 is, for example, a computer and is composed of a CPU, a memory, etc. Note that the function of the control unit 4 may be realized by controlling using software, or may be realized by an operation using hardware.

[0036] Further, the control unit 4 is connected to the proximity sensor 34, and when receiving the detection signal (sensor ON) of the proximity sensor 34, it detects the arrival of the workpiece W as if the workpiece W is placed on the workpiece mounting table 1.

[0037] Thereby, when the workpiece W is placed on the support member 31, the connection member 32 is elastically deformed downward by the self-weight of the workpiece W, and the proximity sensor 34 detects the approach of the detected object 33. Therefore, regardless of the type of the workpiece W and the usage environment of the tray, it is possible to detect the arrival of the workpiece W according to the self-weight of the workpiece W.

[0038] Next, the work placement table 1 according to a modification of the present embodiment will be described with reference to FIG. 3. The work placement table 1 according to this modification is different in that the connecting member 32 is formed in a coil spring shape as compared with the configuration of the work placement table 1 described above. Hereinafter, for the configurations common to the work placement table 1 according to the first embodiment, the same reference numerals will be given and redundant explanations will be omitted.

[0039] In the work placement table 1 according to this modification, the support member 31, the detected object 33, and the connecting member 32 are provided so as to be stacked in this order from above. The upper end portion of the connecting member 32 is joined to the detected object 33, and the lower end portion of the connecting member 32 is attached to the tray 2.

[0040] When the work W is placed on the support member 31, the connecting member 32 contracts due to the weight of the work W, and the proximity sensor 34 detects the approach of the detected object 33. Then, when the control unit 4 receives the detection signal (sensor ON) of the proximity sensor 34, it detects the arrival of the work W as being placed on the work placement table 1.

[0041] The work placement table 1 having such a configuration is suitable for a heavy work W because the coil spring-shaped connecting member 32 is less likely to elastically deform as compared with the leaf spring-shaped one described above.

[0042] Next, the work placement table 1 according to the second embodiment of the present invention will be described with reference to FIG. 4. The work placement table 1 according to this embodiment is different in that it is configured to be able to accommodate work Ws having different outer diameters as compared with the configuration of the work placement table 1 according to the above-described embodiment. Hereinafter, for the configurations common to the work placement table 1 according to the first embodiment, the same reference numerals will be given and redundant explanations will be omitted.

[0043] The work placement table 1 is provided with a detachable adapter 36 at the center of the tray 2. The adapter 36 is formed in a ring shape with a smaller diameter than the tray 2. For example, when the tray 2 corresponds to an 8-inch work W, the adapter 36 corresponds to a 6-inch work W. The adapter 36 is provided with three receiving parts 37 for supporting the work W.

[0044] The support mechanism 3 is configured to be movable in the radial direction of the tray 2 with respect to the tray 2. Specifically, the gripping part 22 is configured to be slidable in the radial direction with respect to the tray 2, and the proximity sensor 34 is embedded on the back surface side of the gripping part 22. Thereby, when the gripping part 22 slides to the adapter 36, the support mechanism 3 can move in the radial direction integrally with the gripping part 22. Therefore, by detaching and attaching the adapter 36 and sliding the gripping part 22, it is possible to correspond to work Ws with different diameters.

[0045] Also, the present invention can be variously modified other than the above as long as it does not depart from the spirit of the present invention, and it is natural that the present invention extends to the modified ones.

Explanation of reference numerals

[0046] 1 ··· Work placement table 2 ··· Tray 21 ··· Receiving part 22 ··· Gripping part 3 ··· Support mechanism 31 ··· Support member 31a ··· Support surface 32 ··· Connection member 33 ··· Object to be detected 34 ··· Proximity sensor 35 ··· Bolt 36 ··· Adapter 37 ··· Receiving part 4 ··· Control unit A ··· Space W ··· Work

Claims

1. A work placement table provided with incoming work detection means for detecting that a work is placed on a tray, wherein the incoming work detection means includes: a support member for supporting the work; a connecting member interposed between the support member and the tray and capable of elastic deformation according to the weight of the work; a detected object that moves on the tray following the elastic deformation of the connecting member; a proximity sensor embedded on the opposite side of the detected object with the tray interposed therebetween, for detecting that the detected object has approached to a predetermined distance; a support mechanism provided movably in the radial direction of the tray; a control unit that determines that the work is placed on the tray and the support member when the proximity sensor detects the approach of the detected object; and is characterized by comprising the above.

2. The work placement table according to claim 1, wherein the connecting member is a leaf spring having a base end fixed to the tray and a support member provided at the tip end.

3. The work placement table according to claim 1 or 2, wherein the support surface of the support member that contacts the work is formed to be convexly curved upward.

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