JP7713495B2 - Workpiece placement table - Google Patents

Description

The present invention relates to a workpiece placement table on which a workpiece is placed.

Conventionally, in manufacturing equipment for workpieces such as semiconductor wafers, a configuration has been known in which the workpiece is temporarily placed on a workpiece placement table when being transferred between pieces of equipment.

For example, Patent Document 1 discloses a wafer polishing apparatus 1 equipped with wafer transfer tables 431, 432 on which the wafer 10 is temporarily placed when the wafer 10 is transferred between the load/unload unit 3 and the polishing head 42. The reference numerals are those in Patent Document 1.

Patent No. 3510177

Meanwhile, the workpiece placement table is provided with a presence sensor that determines whether or not a workpiece is placed on it. Such presence sensors are generally of the reflective or transmissive type.

As shown in Figures 5(a) and (b), when the presence of the workpiece 100 is detected using a reflective presence sensor, a pair of fiber sensors 102 and 103 are provided on the tray 101. Light emitted from one fiber sensor 102 is reflected by the workpiece 100, and this reflected light is received by the other fiber sensor 103. When the amount of received light exceeds a predetermined threshold, it is detected that the workpiece 100 is placed on the tray 101.

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

As shown in Figures 6(a) and (b), when the presence of the workpiece 100 is detected using a transmission type presence sensor, a light 106 is provided to irradiate light toward a fiber sensor 105 provided on the tray 104, and when the light irradiated from the light 106 is blocked by the workpiece W and the amount of received light falls below a predetermined threshold, it is detected that the workpiece 100 is placed on the tray 104.

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

However, when using a reflective presence sensor as described above, if the workpiece 100 has a matte finish or if the workpiece 100 is covered with water, slurry, or other chemicals, the reflected light from the workpiece 100 is diffused, and 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 the presence of the workpiece cannot be detected even if the workpiece 100 is placed on the tray 101.

In addition, when a transmissive presence sensor is used, the light irradiated from the lighting 106 passes through the workpiece 100, which is transparent. 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, so there is a problem that the presence of the workpiece 100 cannot be detected even if it is placed on the tray 104.

As a result, technical issues arise that must be resolved in order to be able to detect the presence of a wide variety of workpieces, and the present invention aims to resolve these issues.

In order to achieve the above-mentioned object, the workpiece mounting table of the present invention is a workpiece mounting table equipped with a load detection means for detecting that a workpiece has been placed on a tray, the load detection means comprising a support member for supporting the workpiece, a connecting member interposed between the support member and the tray and elastically deformable in response to the weight of the workpiece, a detectable object that moves on the tray in accordance with the elastic deformation of the connecting member, and a proximity sensor for detecting when the detectable object has approached within a predetermined distance, a support mechanism arranged to be movable in the radial direction of the tray, and a control unit which determines that the workpiece is placed on the tray and support member when the proximity sensor detects the approach of the detectable object.

With this configuration, when a workpiece is placed on the support member, the weight of the workpiece causes the connecting member to elastically deform downward, causing the proximity sensor to detect the approach of the object to be detected. This makes it possible to detect the presence of a workpiece according to its own weight, regardless of the type of workpiece or the environment in which the tray is used. Furthermore, by configuring the support mechanism to be movable in the radial direction of the tray according to the outer diameter of the workpiece, it is possible to accommodate workpieces of different diameters.

In addition, 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 test object across the tray.

This configuration can prevent the proximity sensor from deteriorating or failing due to water or chemicals adhering to it.

In addition, in the workpiece mounting table according to the present invention, it is preferable that the connecting member is a leaf spring whose base end is fixed to the tray and whose tip end is provided with the support member.

With this configuration, the amount of elastic deformation of the leaf spring according to the weight of the workpiece can be easily adjusted, so the amount of movement of the detected object can be appropriately set depending on the weight of the workpiece.

In addition, it is preferable that the workpiece placement table according to the present invention is configured so that the support surface of the support member that contacts the workpiece is curved in an upwardly convex manner.

With this configuration, the support member comes into contact with the workpiece over a small area, which helps prevent damage to the workpiece.

In the present invention, when a workpiece is placed on the support member, the weight of the workpiece causes the connecting member to elastically deform downward, and the proximity sensor detects the approach of the object to be detected, so that the presence of the workpiece can be detected according to the workpiece's own weight, regardless of the type of workpiece or the environment in which the tray is used.

1A is a plan view, a longitudinal sectional view, and an enlarged sectional view of a main portion, which are schematic views of a workpiece mounting table according to a first embodiment of the present invention; 3A and 3B are a longitudinal sectional view and an enlarged sectional view of a main part of the workpiece placing table showing a state in which a workpiece is placed on the workpiece placing table; FIG. 13 is an enlarged cross-sectional view of a main part of a workpiece placement table according to a modified example. 13A and 13B are a plan view and a longitudinal sectional view showing a workpiece mounting table according to a second embodiment; 1A and 1B are a plan view and a longitudinal sectional view showing a conventional workpiece placement table using a reflective load sensor; 1A and 1B are a plan view and a longitudinal sectional view showing a conventional workpiece placement table using a transmission type load sensor;

The embodiment of the present invention will be described with reference to the drawings. Note that in the following, when referring to the number, numerical value, amount, range, etc. of components, unless otherwise specified or when it is clearly 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.

In addition, when referring to the shape or positional relationship of components, etc., this includes things that are substantially similar or similar to that shape, etc., unless otherwise specified or considered in principle to be clearly different.

In addition, drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional ratios of components may not be the same as in reality. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

Figure 1 is a perspective view showing a schematic diagram of a workpiece placement table 1 according to a first embodiment of the present invention. The workpiece placement table 1 is used to temporarily place a workpiece when transferring the workpiece in a semiconductor manufacturing device, and is, for example, a workpiece transfer table provided between a transport robot and a polishing device, or a workpiece receiving table used when transferring workpieces between multiple transport robots.

The workpiece placement table 1 includes a tray 2 and a support mechanism 3. The tray 2 is made of a resin material that can detect when a detection target 33 approaches a proximity sensor 34, and is formed in a disk shape. On the front side of the tray 2, three receiving portions 21 are provided to receive the peripheral edge of the rear surface of the workpiece W.

The support mechanism 3 detects the presence of the workpiece W by the weight of the workpiece W. The support mechanism 3 and the three receiving portions 21 are arranged concentrically and equally spaced apart from each other when viewed from above. The support mechanism 3 includes a support member 31, a connection member 32, a detected object 33, and a proximity sensor 34.

The support member 31 is provided at the tip of the connection member 32 and supports the rear peripheral edge of the workpiece W. The support surface 31a of the support member 31 is formed to be convexly curved upward. This allows the support member 31 to support the workpiece W with a small area. The support member 31 is made of resin, and is preferably made of a material that is particularly low in dust generation and chemical resistance, such as polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), etc.

The base end of the connection member 32 is joined to the tray 2. Specifically, the base end of the connection member 32 is gripped by a pair of upper and lower gripping parts 22 provided on the outer periphery of the tray 2, and the gripping parts 22 and the connection member 32 are fastened with a bolt 35, thereby integrating the connection member 32 with the tray 2. A wedge-shaped space A is formed between the pair of gripping parts 22.

The connection member 32 is made of metal or resin, and is preferably one that is particularly resistant to chemicals and does not swell easily, such as PTFE, PEEK, or PPS. The connection member 32 is configured to elastically deform appropriately according to the weight of the workpiece W. As a result, when the workpiece W is placed on the support member 31, the connection member 32 elastically deforms so as to bend downward within the space A around the part gripped by the gripping portion 22.

For example, for a workpiece W weighing a few grams, the thickness of the connecting member 32 may be about 0.2 mm. 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; a thickness greater than this will excessively increase the rigidity and make it difficult for the workpiece W to deform under its own weight. Therefore, when changing the spring constant of the connecting member in accordance with a relatively heavy workpiece W, it is preferable to configure it so that multiple thin connecting members 32 are stacked on top of each other, rather than using a single thick connecting member 32.

The detectable object 33 is provided on the opposite side of the support member 31 with the connecting member 32 in between. The detectable object 33 is fixed to the tip of the connecting member 32 and is configured to be able to move up and down together with the connecting member 32 in response to the weight of the workpiece W. The detectable object 33 is a metal object that can be detected by the proximity sensor 34. The detectable object 33 is preferably made of a metal that is resistant to rust, such as stainless steel. The surface of the detectable object 33 may be coated with Teflon to suppress the elution of metal ions.

The proximity sensor 34 is embedded in the tray 2 below the object to be detected 33. Specifically, the proximity sensor 34 is provided at a position where it can detect the object to be detected 33 when the connecting member 32 is elastically deformed to its lower limit by the weight of the workpiece W. The detection range of the proximity sensor 34 can be changed as desired using a rotary adjustment trimmer or the like. The proximity sensor 34 is embedded on the back side of the tray 2, and deterioration or failure of the proximity sensor 34 caused by adhesion of water or chemicals can be suppressed. When the proximity sensor 34 detects the approach of the object to be detected 33, it sends a detection signal to the control unit 4.

The operation of the workpiece mounting table 1 is controlled by the control unit 4. The control unit 4 controls each of the components that make up the workpiece mounting table 1. The control unit 4 is, for example, a computer, and is composed of a CPU, memory, etc. The functions of the control unit 4 may be realized by control using software, or may be realized by something that operates using hardware.

The control unit 4 is also connected to a proximity sensor 34, and when it receives a detection signal (sensor ON) from the proximity sensor 34, it detects the presence of a workpiece W placed on the workpiece placement table 1.

As a result, when the workpiece W is placed on the support member 31, the workpiece W's own weight causes the connecting member 32 to elastically deform downward, and the proximity sensor 34 detects the approach of the detected object 33, so that the presence of the workpiece W can be detected according to the workpiece W's own weight, regardless of the type of workpiece W or the environment in which the tray is used.

Next, a workpiece mounting table 1 according to a modified example of this embodiment will be described with reference to FIG. 3. The workpiece mounting table 1 according to this modification differs from the configuration of the workpiece mounting table 1 described above in that the connection member 32 is formed in a coil spring shape. In the following, configurations common to the workpiece mounting table 1 according to the first embodiment will be given the same reference numerals, and duplicated descriptions will be omitted.

In the workpiece placement table 1 according to this modified example, the support member 31, the object to be detected 33, and the connection member 32 are arranged in this order, stacked from the top. The upper end of the connection member 32 is joined to the object to be detected 33, and the lower end of the connection member 32 is attached to the tray 2.

When the workpiece W is placed on the support member 31, the connection member 32 contracts due to the weight of the workpiece W, and the proximity sensor 34 detects the approach of the detected object 33. When the control unit 4 receives a detection signal (sensor ON) from the proximity sensor 34, it detects the presence of the workpiece W as being placed on the workpiece placement table 1.

A workpiece mounting table 1 configured in this manner is suitable for heavy workpieces W because the coil spring-shaped connecting member 32 is less susceptible to elastic deformation than the leaf spring-shaped one described above.

Next, a workpiece mounting table 1 according to a second embodiment of the present invention will be described with reference to FIG. 4. The workpiece mounting table 1 according to this embodiment differs from the configuration of the workpiece mounting table 1 according to the above-described embodiment in that it is configured to be capable of handling workpieces W of different outer diameters. In the following, configurations common to the workpiece mounting table 1 according to the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted.

The workpiece placement table 1 is provided with a removable adapter 36 in 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, if the tray 2 is capable of handling an 8-inch workpiece W, the adapter 36 is capable of handling a 6-inch workpiece W. The adapter 36 has three receiving portions 37 that support the workpiece W.

The support mechanism 3 is configured to be movable in the radial direction of the tray 2 relative to the tray 2. Specifically, the gripping portion 22 is configured to be slidable in the radial direction relative to the tray 2, and the proximity sensor 34 is embedded in the back side of the gripping portion 22. As a result, when the gripping portion 22 slides to the adapter 36, the support mechanism 3 can move in the radial direction together with the gripping portion 22. Therefore, by attaching and detaching the adapter 36 and sliding the gripping portion 22, it is possible to accommodate workpieces W of different diameters.

Furthermore, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

Reference Signs List 1 Workpiece placement table 2 Tray 21 Receiving portion 22 Grip portion 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 portion 4 Control portion A Space W Workpiece

Claims (3)

A work placement table equipped with a load detection means for detecting that a work is placed on a tray,
The presence detection means is
A support member for supporting the workpiece;
A connection member interposed between the support member and the tray and elastically deformable in response to the weight of the workpiece;
a detection object that moves on the tray in response to elastic deformation of the connection member;
a proximity sensor that is embedded on the opposite side of the detection object across the tray and detects when the detection object approaches within a predetermined distance;
a support mechanism provided so as to be movable in a radial direction of the tray;
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 detection object;
A workpiece mounting table comprising: 2. The workpiece mounting table according to claim 1 , wherein the connecting member is a leaf spring having a base end fixed to the tray and a tip end to which the supporting member is provided. 3. The workpiece mounting table according to claim 1, wherein the support surface of the support member that comes into contact with the workpiece is curved upwardly and convexly.