JP7688566B2 - Wafer Holding Device - Google Patents

Description

The present invention relates to a wafer holding device that receives a wafer (a roughly circular thin plate) transported by a handler or the like in a horizontal position and holds it in a specified position. For example, the wafer holding device is incorporated into a processing device that processes and treats the wafer, or an appearance inspection device that photographs and inspects the appearance of device chips formed on the wafer.

Semiconductor devices are formed by stacking many semiconductor device circuits (i.e., the repeating external pattern of device chips) in layers on a single semiconductor wafer, which is then singulated into individual chip components, which are then packaged and shipped as individual electronic components or incorporated into electrical products.

Then, before the individual chip components are separated, an inspection image of the repeating appearance pattern of the device chips formed on the wafer is compared with a reference image to inspect the quality of each chip component (for example, Patent Document 1).

Then, the wafer to be inspected is transported from a cassette carrier or the like to the visual inspection device by an automatic transport device called a handler, which dispenses inspected substrates and delivers uninspected substrates.

Generally, wafers to be inspected using visual inspection equipment are supported from the entire bottom side by a wafer holder with a flat top surface and are held by suction or the like to be imaged and inspected (for example, Patent Document 2).

JP 2007-155610 A JP 2006-269989 A

However, if the top and bottom surfaces of the wafer to be held have functional areas on which films such as wiring patterns are formed, it is prohibited to support the entire bottom surface of the wafer with a flat wafer holder. In addition, posture correction by contacting the top surface of the wafer with a pressing member, and pressure and posture correction by air blowing, etc. may also be prohibited.

Furthermore, if the wafer being inspected is thin or has residual stress, even if an attempt is made to hold the outer periphery of the wafer in a flat position, warping or deformation is likely to occur, causing part of the wafer's outer periphery to float, making it impossible to hold it in the desired position.

Therefore, the present invention has been made in consideration of the above problems,
To provide a wafer holding device capable of surely holding a wafer which is prone to warping or deformation in a desired posture even when only a part of the lower outer periphery of the wafer is allowed to come into contact with the wafer.

In order to solve the above problems, one aspect of the present invention is to
A wafer holding device that receives a wafer in a horizontal state and holds it in a predetermined position,
A first support part that supports from below a first support portion that is set in at least three places in a contact allowable region set in a lower part of the outer periphery of the wafer so as to surround the center of the wafer;
a second support portion that supports, from below, a second support region that is set at a position that fills the gap between the first support portions within the contact allowable region;
a third support portion that supports, from below, a third support region that is set at a position that fills the gap between the first support portion and the second support portion within the contact allowable region;
a first lifting unit that changes a relative height between an upper end of the first support unit and an upper end of the second support unit;
a second lifting unit that changes a relative height between an upper end of the second support unit and an upper end of the third support unit;
a negative pressure suction unit that generates a negative pressure in the first support portion to suction and hold the wafer;
A control unit is provided for controlling a change in the relative height of the first lifting unit and the second lifting unit and switching between suction hold and release by the negative pressure suction unit,
The control unit
a first support mode in which the upper end of the first support portion is disposed above a height of an upper end of the second support portion and an upper end of the third support portion;
a second support mode in which the upper end of the first support portion and the upper end of the second support portion are disposed at the same height, above the height of the upper end of the third support portion;
a third support mode in which the height of the upper end of the first support portion and the height of the upper end of the second support portion are disposed at the same height as the height of the upper end of the third support portion;
The wafer received in the first supporting mode is held by suction while the mode is switched from the first supporting mode to the second supporting mode, and then the mode is switched to the third supporting mode.

According to the above aspect, the locations and areas that support the wafer can be increased in stages, so even for wafers that are prone to warping or deformation, it is possible to hold the outer periphery in the desired position while preventing partial lifting of the outer periphery.

When holding a wafer that is prone to warping or deformation, even if only a portion of the lower periphery of the wafer is allowed to be in contact, the wafer can be reliably held in the desired position.

1 is a perspective view showing an example of a wafer holding device in an embodiment of the present invention. 1 is a plan view showing an example of a wafer holding device in an embodiment embodying the present invention. 1 is a block diagram showing an example of a wafer holding device in an embodiment of the present invention. 1 is a cross-sectional view showing an example of a wafer holding device in an embodiment of the present invention. FIG. 2 is a flow chart showing an example of an operational flow in an embodiment of the present invention. FIG. 13 is a perspective view showing an example of a wafer holding device in another embodiment of the present invention. FIG. 11 is a cross-sectional view showing an example of a wafer holding device in another embodiment of the present invention. FIG. 11 is a flow chart showing an example of an operational flow in another embodiment of the present invention. FIG. 11 is a cross-sectional view showing an example of a wafer holding device in still another embodiment of the present invention. FIG. 11 is a flow chart showing an example of an operational flow in yet another embodiment of the present invention.

Below, an embodiment of the present invention will be described with reference to the drawings. In the following description, the three axes of the Cartesian coordinate system are designated as X, Y, and Z, the horizontal direction is expressed as the X direction and the Y direction, and the direction perpendicular to the XY plane (i.e., the direction of gravity) is expressed as the Z direction. In addition, the direction against gravity in the Z direction is expressed as up, and the direction in which gravity acts is expressed as down.

Figure 1 is a perspective view showing an example of a wafer holding device in a form embodying the present invention. Figure 2 is a plan view showing an example of a wafer holding device in a form embodying the present invention. Figures 1 and 2 show each part constituting the wafer holding device 1 according to the present invention and an example of its arrangement. Figure 3 is a block diagram showing an example of a wafer holding device in a form embodying the present invention. Figure 3 illustrates an example of the relationship between each part constituting the wafer holding device 1 according to the present invention and the control unit.

The wafer holding device 1 receives the wafer W transported by a handler (not shown) in a horizontal state and holds it in a predetermined position. In the wafer W to be held, contact is not permitted in the area where a circuit pattern is formed or the area where a functional film is formed (generally the inner part of the outer edge and a part of the periphery) to prevent adhesion of dirt or foreign matter, scratches, dents, etc. On the other hand, the area outside these areas (the outer edge and a part of the periphery) is called a contact-permitted area R, and contact is permitted for handling, etc.
Specifically, the wafer holding device 1 includes a first support section 2, a second support section 3, a third support section 4, a first lift section 5, a second lift section 6, a negative pressure suction section 8, a control section 9, and the like.

The first support portion 2 supports from below the first support portion S1, which is set in at least three locations within the contact-permitted region R set in the lower outer periphery Wb of the wafer W so as to surround the center Wc of the wafer W. Specifically, the first support portion 2 includes a first abutment support portion 21, a support pillar 22, a connecting portion 23, etc.

The first contact support portion 21 comes into contact with a first support portion S1 of the lower outer periphery Wb of the wafer W, and supports and holds the first support portion S1 from below.
Specifically, when viewed in a plan view and based on the center Wc of the wafer W, the first support portions S1 are set at three locations spaced at intervals of approximately 120 degrees, and the first abutment support portions 21 are arranged at three locations so as to correspond in position to these portions S1.
More specifically, the first abutment support portion 21 is disposed at the upper end of the first support portion 2, and its main body is made of metal, resin, rubber, etc., and has a structure (e.g., cylindrical) with an air communication port through which air communicates with the upper end.

The support pillar 22 aligns the upper end position of the first contact support portion 21 to a predetermined height. Specifically, the support pillar 22 is composed of a rod-shaped member having a predetermined length in the thickness direction (Z direction) of the wafer W.

The connecting parts 23 fix the lower parts of the support columns 22 and connect them to the first lifting part 5. Specifically, the connecting parts 23 are roughly Y-shaped in plan view and are made of plate-like members that extend radially from near the center.

The second support portion 3 supports from below the second support portion S2, which is set at a position that fills the gap between the first support portions S1 in the contact-permitted region R set at the lower outer periphery Wb of the wafer W. Specifically, the second support portion 3 includes a second abutment support portion 31, a support pillar 32, a connecting portion 33, etc.

The second abutment support portion 31 abuts against a second support portion S2 set at a position that fills the gap between the first support portions S1 on the lower outer periphery Wb of the wafer W, and supports the second support portion S2 from below.
Specifically, when viewed in a plane and based on the center Wc of the wafer W, the second support portions S2 are set at three locations spaced apart at positions shifted by approximately 60 degrees from the first support portion S1, and the second abutment support portions 31 are arranged so that their positions correspond to those of these portions S2.
More specifically, the second abutment support portion 31 is disposed at the upper end of the second support portion 3, and its main body is made of metal, resin, rubber, etc., and has a structure (e.g., cylindrical) with an air communication port through which air communicates with the upper end.

The support pillar 32 aligns the upper end of the second contact support portion 31 to a predetermined height. Specifically, the support pillar 32 is a rod-shaped member having a predetermined length in the thickness direction (Z direction) of the wafer W.

The connecting parts 33 fix the lower parts of the support columns 32 and connect them to the second lifting part 6. Specifically, the connecting parts 33 are roughly Y-shaped in plan view and are made of plate-like members that extend radially from near the center.

The third support portion 4 supports from below the third support portion S3, which is set at a position that fills the gap between the first support portion S1 and the second support portion S2 in the contact-permitted region R set at the lower outer periphery Wb of the wafer W. Specifically, the third support portion 4 includes a third contact support portion 41, a support pillar 42, an arc-shaped contact support portion 43, etc.

The third abutment support portion 41 abuts against at least a portion (circular area) of the third support portion S3 which is set at a position that complements the gap between the first support portion S1 and the second support portion S2 on the lower outer periphery Wb of the wafer W, and supports the third support portion S3 from below.
Specifically, when viewed in a plane, with the center Wc of the wafer W as a reference, the third abutment support portion 41 is arranged in six locations spaced apart from the first abutment support portion 21 or the second abutment support portion 31 at positions shifted by approximately 30 degrees.
More specifically, the third abutment support portion 41 is disposed at the upper end of the third support portion 4, and its main body is made of metal, resin, rubber, etc., and has a structure (e.g., cylindrical) with an air communication port through which air communicates with the upper end.

The support pillar 42 aligns the upper end of the second contact support portion 31 at a predetermined height.
Specifically, the support pillar 42 is configured as a rod-shaped member having a predetermined length in the thickness direction of the wafer W (Z direction).

The arc-shaped contact support portion 43 contacts with the arc-shaped region of the third support portion S3 set at a position that fills the gap between the first support portion S1 and the second support portion S2 in the contact allowance region R set in the outer circumferential lower portion Wb of the wafer W, and supports the region from below. Furthermore, the arc-shaped contact support portion 43 is disposed with its upper end set at the same height as the upper end of the third contact support portion 41.
Specifically, when viewed in a plan view and based on the center Wc of the wafer W, the arc-shaped abutment support portion 43 is an arc-shaped member that follows the outer edge shape of the wafer W and is arranged in a position (e.g., 12 locations) that fills the gaps between the first abutment support portion 21, the second abutment support portion 31, and the third abutment support portion 41.
More specifically, the arc-shaped contact support portion 43 is made of metal, resin, rubber, or the like, and is attached to the device frame 1f via a connecting metal fitting or the like (not shown).
In addition, "the same height" does not only mean a state in which the height is the same in microns, but also includes a state in which the height can be considered the same to the extent that it does not interfere with handling the wafer W, and may include some error in the vertical direction (for example, an error in millimeters caused by deformation of an elastic member) (the same applies below).

The first lifting section 5 changes the relative height between the upper end of the first support section 2 and the upper end of the second support section 3 .
Specifically, the first lifting section 5 raises and lowers the first support section 2 in the thickness direction (Z direction) of the wafer W, and includes a rod 51 that raises and lowers the connecting member 23 of the first support section 2 in the vertical direction (Z direction), and a main body section 52 attached to the frame 1f.
More specifically, the first lifting unit 5 is composed of a mechanism (so-called actuator) that converts rotational motion, such as a rack and pinion mechanism or a cam mechanism, into linear motion, and is equipped with a motor (such as a stepping motor or a servo motor) that performs rotational motion. This motor is connected to the control unit 8, and rotates at a predetermined number of rotations and stops at a predetermined angle. Therefore, the first lifting unit 5 can move the rod 51 at a predetermined speed and stop it at a predetermined position based on a control signal from the control unit 8. Therefore, the first lifting unit 5 can move the first support unit 2 in the vertical direction and stop it at a predetermined height.

The second lifting section 6 changes the relative height between the upper end of the second support section 3 and the upper end of the third support section 4 .
Specifically, the second lifting section 6 raises and lowers the second support section 4 in the thickness direction (Z direction) of the wafer W, and includes a rod 61 that raises and lowers the connecting member 33 of the second support section 3 in the vertical direction (Z direction), and a main body section 62 attached to the frame 1f.
More specifically, the second lifting unit 6 has a similar configuration to the first lifting unit 5, and can move the rod 61 at a predetermined speed and stop it at a predetermined position based on a control signal from the control unit 8. Therefore, the second lifting unit 6 can move the second support unit 3 in the vertical direction and stop it at a predetermined height.

The negative pressure suction unit 8 generates a negative pressure at the first supporting portion S1, the second supporting portion S2 and the third supporting portion S3 to suction and hold the wafer W.
Specifically, the negative pressure suction section 8 suction-holds the wafer W by generating negative pressure at the upper ends of the first support section 2, the second support section 3, and the third support section 4, which abut against the lower outer periphery Wb of the wafer W.
More specifically, the negative pressure suction section 8 is composed of air piping connected to the air communication ports of the first abutment support section 21, the second abutment support section 31 and the third abutment support section 41, a switching valve, a negative pressure generating means, etc.

The switching valves individually switch between connecting each of the air communication ports of the first contact support part 21, the second contact support part 31, and the third contact support part 41 to the negative pressure generating means (i.e., suction holding) or to the atmosphere (i.e., suction release), and are connected to the control part 8.

Examples of negative pressure generating means include a vacuum pump, an ejector, a pressure tank connected to them, and connecting piping.

The first contact support portion 21, the second contact support portion 31, and the third contact support portion 41 are connected to a negative pressure generating means such as a vacuum pump via a switching valve or the like. The first contact support portion 21, the second contact support portion 31, and the third contact support portion 41 can hold or release the wafer W by switching between a negative pressure state or an open-to-atmosphere state by controlling the switching valve or the like by the control portion 8.

The control unit 9 controls the change in the relative height of the first lifting unit 5 and the second lifting unit 6. Furthermore, the control unit 9 controls the switching of the negative pressure suction unit 8 between suction hold and release.
Specifically, the control unit 9 controls the motor of the first lifting unit 5 and the motor of the second lifting unit 6 to change the height at which the wafer W is supported and held to an upper position H/middle position M/lower position L. The control unit 9 has a first support mode for switching to the upper position H, a second support mode for switching to the middle position M, and a third support mode for switching to the lower position L, and can switch between these support modes. Note that the upper position H/middle position M/lower position L referred to here are names defined based on the relative positions of the upper ends of the first support unit 2, the second support unit 3, and the third support unit 4, regardless of the difference in the height at which the wafer W is supported.

More specifically, the control unit 9 is composed of a computer, a programmable logic controller, etc. (i.e., hardware) and its execution program, etc. (i.e., software), and is configured to input and output control signals to and from each part to be controlled (the motors of the first lifting unit 5 and the second lifting unit 5, the switching valve of the negative pressure suction unit 8, etc.) and perform predetermined control processing.

4A and 4B are cross-sectional views showing an example of a wafer holding device according to an embodiment of the present invention, in which a wafer W is supported at an upper position H. FIG.
FIG. 4(b) shows a state in which the wafer W is supported at the middle position M.
FIG. 4(c) shows a state in which the wafer W is supported at the lower position L.

The upper position refers to a positional relationship in which the upper end of the first support part 2 is located higher than the upper ends of the second support part 3 and the third support part 4. A mode in which the device transitions to this state and maintains this state is called a "first support mode."
Specifically, in the first support mode, the upper end of the first abutment holder 21 is disposed above the height of the upper ends of the second abutment holder 31 and the third abutment holder 41 .

When the wafer W is lowered from above in the first support mode (upper position) to perform the transfer operation, the first abutment holder 21 abuts against the first support portion S1 of the wafer W, but the second support portion S2 and the second abutment holder 31, and the third support portion S3 and the third abutment holder 41 are separated. At this time, the wafer W, which is supported at three points on the lower periphery, is prone to bending, and the portions of the wafer W other than the first support portion S1 (for example, the second support portion S2) often become droopy.

The middle position refers to a positional relationship in which the upper ends of the first support part 2 and the second support part 3 are located at the same height, above the height of the upper end of the third support part 4. The mode in which the state is transitioned to and maintained in this state is called the "second support mode."
Specifically, in the second support mode, the upper ends of the first support portion 2 and the second support portion 3 are positioned at the same height, above the height of the upper end of the third abutment holding portion 41 .

When the state in which the wafer W is held in the first support mode (upper stage position) is switched to the second support mode (middle stage position), the first support portion S1 of the wafer W remains in contact with the first contact holding portion 21, and the second support portion S2 also comes into contact with the second contact holding portion 31. That is, the number of places supporting the outer circumferential lower portion Wb of the wafer W increases and the supporting interval becomes narrower.
At this time, the deflection of the wafer W, which is supported at six points on the lower outer periphery, is improved, and sagging of the wafer W at portions other than the first support portion S1 and the second support portion S2 (e.g., the third support portion S3, etc.) is reduced.

The lower position refers to a positional relationship in which the height of the upper ends of the first support portion 2 and the second support portion 3 is the same as the height of the upper end of the third support portion 4. A mode in which the device transitions to this state and maintains this state is called a "third support mode."
Specifically, in the third support mode, the height of the upper end of the first abutment holder 21 and the upper end of the second abutment holder 31 are positioned at the same height as the upper end of the third abutment holder 41 .

When the wafer W is held in the second support mode (middle position) and then switched to the third support mode (lower position), the first support portion S1 of the wafer W abuts against the first abutment holding portion 21, the second support portion S2 remains in abutment against the second abutment holding portion 31, and then the third support portion S3 abuts against the third abutment holding portion 41.
At this time, since the lower periphery of the wafer W is supported around the entire periphery, the center Wc becomes indented due to its own weight, but if one focuses only on the periphery, the sagging is improved and the wafer W is supported in a flat state.

<Operation flow>
FIG. 5 is a flow diagram showing an example of an operational flow in an embodiment embodying the present invention.

First, if the wafer W can be received by the wafer holding device 1, the control unit 9 switches to the first support mode (upper stage position) and waits (step s1).

Then, the wafer W is placed (step s2), and the first support portion S1 of the wafer W is held by suction (step s3).

Then, the first lifting unit 5 and the second lifting unit 6 are controlled to switch to the second support mode (middle position) (step s4), and then to the third support mode (lower position) (step s5). When switching from the first support mode (upper position) to the second support mode (middle position), negative pressure is generated at the second support site S2 to suction and hold the wafer W, and when switching from the second support mode (middle position) to the third support mode (lower position), negative pressure is generated at the third support site S3 to suction and hold the wafer W.

Then, the desired processing, inspection, etc. is executed (step s6), and it is determined whether the processing, etc. is completed (step s7). If the processing, etc. is not completed, the above-mentioned step s6 is continued, and if the processing, etc. is completed, the series of flows is terminated.

Because of this configuration, the wafer holding device 1 of the present invention can gradually increase the locations and areas that support the wafer W, so that even for wafers W that are prone to warping or deformation, it is possible to hold the outer periphery in a desired position while preventing partial lifting of the outer periphery. Therefore, when holding a wafer that is prone to warping or deformation, even if only a portion of the lower periphery of the wafer is allowed to be in contact, it is possible to reliably hold the wafer in a desired position.

[Modification]
(Regarding the third support portion 4)
In the above description, the third support portion 4 is exemplified by a configuration including the third contact support portion 41 and the arc-shaped contact support portion 43. In this case, the third support portion S3 is set to have an arc shape that follows the outer edge shape of the wafer W to be held.
Such a configuration is more preferable because it is possible to support most of the contact allowable region R set in the outer circumferential lower portion Wb of the wafer W and to support the wafer W in an extremely flat state.

However, the third support portion 4 is not limited to this configuration, and the present invention can be realized even with other configurations.
For example, the third contact support portion 41 may be omitted, and the arc-shaped contact support portion 43 may be arranged at a distance in a plurality of locations. Alternatively, the arc-shaped contact support portion 43 may be omitted, and the third contact support portion 41 may be arranged at a distance in a plurality of locations. Even with such a configuration, the contact allowable region R set in the outer circumferential lower portion Wb of the wafer W is supported at a plurality of locations all around the circumference, so that the wafer W can be reliably held in a desired posture.

In the above description, the first support portion S1 and the second support portion S2 are set at positions that are arranged at 60 degree intervals from each other when viewed in a plan view and the center Wc of the wafer W is used as a reference, and the third support portion S3 is set at a position that complements the gap between them, and the first abutment support portion 21, the second abutment support portion 31, the third abutment support portion 41, and the arc-shaped abutment support portion 43 are arranged at positions corresponding to these portions S1 to S3. This configuration is preferable because it is easy to improve the warping of the wafer outer periphery when the outer periphery of the wafer W is evenly distributed and supported from below, and the support state is switched from the upper position to the middle position to the lower position. However, the first support portion S1 and the second support portion S2 are not limited to such an even arrangement and may be changed as appropriate. In addition, the first support portion S1 may be set at four or more locations, and the second support portion S2 may be set at four or more locations. The number of these support points can be determined appropriately depending on the thickness, deformation, residual stress, etc. of the wafer W.

(Regarding negative pressure suction unit 8)
In the above description, a configuration has been exemplified in which negative pressure is generated at the first supporting portion S1, the second supporting portion S2, and the third supporting portion S3 to suction and hold the wafer W as the negative pressure suction portion 8. Furthermore, a flow has been exemplified in which the control portion 9 generates a negative pressure at the second supporting portion S2 to suction and hold the wafer W when switching to the second supporting mode (middle position), and generates a negative pressure at the third supporting portion S3 to suction and hold the wafer W when switching to the third supporting mode (lower position).
With this configuration, the number of locations and areas to be subjected to negative pressure suction can be increased even if the width (i.e., the radial length) of the contact allowance region R set in the outer circumferential lower portion Wb of the wafer W is short. Therefore, even if the pressure for suction-holding the wafer W is set low, the overall holding force can be increased, and the wafer W is less likely to come off even if an external force is applied while being held, which is preferable.

However, the negative pressure suction section 8 is not limited to this configuration, and the present invention can be realized with other configurations. For example, the arc-shaped contact support section 43 can be made of a porous material, or grooves or pores can be provided on the upper surface of the arc-shaped contact support section 43 to allow air to pass through, and it can be connected to a negative pressure generating means in the same way as the third contact support section 41. This can further increase the number of locations and areas that are subjected to negative pressure suction. Therefore, even if the pressure for suctioning and holding the wafer W is set low, the overall holding force can be increased, and it is more preferable because it is less likely to come off even if an external force is applied while holding it.

Alternatively, negative pressure may be generated only at the first support portion S1, or at the first support portion S1 and the second support portion S2. Even with such a configuration, a negative pressure suction force acts on the contact allowance region R set at the lower outer periphery Wb of the wafer W, so the wafer W can be reliably held in the desired position.

(Regarding the first support portion 2 and the second support portion 3)
In the above description, the pillars 32 of the second support section 3 are longer than the pillars 22 of the first support section 2, and the connecting members 23 of the first support section 2 are disposed above the connecting members 33 of the second support section 3. However, the first support section 2 and the second support section 3 are not limited to such a configuration, and the present invention can be realized with other configurations. For example, the connecting members 23 of the first support section 2 may be disposed below the connecting members 33 of the second support section 3, and the pillars 22 of the first support section 2 may be longer than the supporting members 32 of the second support section 3. In this case, the length of the pillars 22 of the first support section 2 is set in consideration of a clearance that prevents the connecting members 23 and 33 from interfering with each other due to the change between the upper stage position and the middle stage position.

In the above description, the first lifting unit 5 and the second lifting unit 6 are independently attached to the device frame 1f, and the first lifting unit 5 and the second lifting unit 6 are each equipped with a motor. This configuration is preferable because it allows for precise control of the position and movement speed of the upper ends of the first support unit 2 and the second support unit 3 by controlling the rotation angle and rotation speed of the motor.

However, the first lifting/lowering section 5 and the second lifting/lowering section 6 are not limited to this configuration, and the present invention can be realized with other configurations. For example, the first lifting/lowering section 5 may be attached to the connecting member 33 of the second support section 3 (a so-called two-tiered structure). In this case, the first lifting/lowering section 5 and the second lifting/lowering section 6 may be a lifting mechanism that uses the rotation of a motor, or may use an actuator such as an air cylinder.

In the above description, the first lifting unit 5 is exemplified as a configuration in which the first support unit 2 is raised and lowered in the thickness direction (Z direction) of the wafer W, and the second lifting unit 6 is exemplified as a configuration in which the second support unit 3 is raised and lowered in the thickness direction (Z direction) of the wafer W. With such a configuration, the wafer W is lowered from the upper position H to the middle position M, and then from the middle position M to the lower position L, so that the center of gravity at the lower position can be lowered downward. In addition, the number of parts is relatively small, and the actuators of the first lifting unit 6 and the second lifting unit 7 can be made smaller in size to raise and lower a light-weight unit. Therefore, it is preferable to incorporate the wafer holding device 1 into an inspection device, process equipment, etc. for use.

However, the first lifting/lowering unit 5 and the second lifting/lowering unit 6 are not limited to this configuration, and may be configured as described below. For example, the first support unit 3 may be fixed, the second support unit 3 is lifted/lowered by the first lifting/lowering unit 5, and the third support unit 4 is lifted/lowered by the second lifting/lowering unit 6 (so-called rise structure).
In this case, the state in which the second support portion 3 and the third support portion 4 are lowered and the upper end of the first support portion 3 is at the uppermost position is defined as the upper stage position H. Also, the state in which the second support portion 3 is raised while the third support portion 4 remains lowered and the upper ends of the first support portion 3 and the second support portion 4 are higher than the upper end of the third support portion 4 is defined as the middle stage position. Also, the state in which the second support portion 3 and the third support portion 4 are raised and the upper ends of the first support portion 3, the second support portion 4, and the third support portion 4 are at the same height is defined as the lower stage position.

Also, in the above description, a configuration has been given as an example of the first lifting unit 5 in which a single actuator lifts and lowers the connecting member 23 of the first support unit 2 in the vertical direction. With this configuration, the multiple sets of first abutment support units 21 and pillars 22 can be raised and lowered as a unit. However, the first lifting unit 5 is not limited to this configuration, and may be configured to lift and lower the multiple sets of first abutment support units 21 and pillars 22 independently. With this configuration, there is no need to provide a connecting member 23 in the first support unit 2, and it can be designed without worrying about interference with the connecting member 33 of the second support unit 3.

Also, in the above description, the second lifting unit 6 is exemplified as being configured to use one actuator to lift the connecting member 33 of the second support unit 3 in the vertical direction. With this configuration, the multiple sets of second abutment support units 31 and pillars 32 can be lifted and lowered as a unit. However, the second lifting unit 6 is not limited to this configuration, and may be configured to lift and lower the multiple sets of second abutment support units 31 and pillars 32 independently. With this configuration, there is no need to provide a connecting member 33 in the second support unit 3, and it can be designed without worrying about interference with the connecting member 23 of the first support unit 2.

In the above description, a configuration is exemplified in which the first support section 2, the second support section 3, and the third support section 4 are provided, and the control section 9 switches from the first support mode to the second support mode, and then switches to the third support mode. However, in applying the present invention, a configuration may be used in which multiple support sections are provided at finer pitches, and a lifting section that changes the relative heights of their upper ends is provided, and the control section supports the wafer while increasing the number of support points in more stages.

(The following is added by Kunio)
Incidentally, such a mode in which the height at which the wafer W is supported and held is changed while increasing the number of supporting points in multiple stages of three or more stages is called a "first lifting mode."

[Second embodiment]
In realizing the present invention, the control unit 9 of the wafer holding device 1 may have, in addition to this first lifting/lowering mode, a "second lifting/lowering mode" which will be described in detail below, and may be configured to select and execute either the first lifting/lowering mode or the second lifting/lowering mode.

Figure 6 is a perspective view showing an example of a wafer holding device in another embodiment of the present invention. Figure 6 shows the state in which the connecting portion 33 of the second support portion 3, which was attached at the position indicated by the dashed line, has been removed.

Specifically, the wafer holding device 1 has a structure in which the second support part 3 is detachable, and the control part 9 selects and executes either the first lifting mode or the second lifting mode depending on the attachment state of the second support part 3. More specifically, the control part 9 executes the first lifting mode when the second support part 3 is attached, and executes the second lifting mode when the second support part 3 is detached. The second lifting mode has a fourth support mode and a fifth support mode, and switches from the fourth support mode to the fifth support mode while suction-holding the wafer W received in the fourth support mode.

In the fourth support mode, the upper end of the first support portion 2 is disposed at a height higher than the upper end of the third support portion 4 .
Specifically, in the fourth support mode, the actuator of the first lifting section 5 is controlled to change the height at which the wafer W is supported and held so that the height of the upper end of the first abutment holding section 21 is positioned at an upper position H that is higher than the height of the upper end of the third abutment holding section 41 (i.e., the lower position).

In the fifth support mode, the height of the upper end of the first support portion 2 is set to the same height as the height of the upper end of the third support portion 4 .
Specifically, in the fifth support mode, the actuator of the first lifting section 5 is controlled to change the height at which the wafer W is supported and held so that the height of the upper end of the first abutment holding section 21 is positioned at the same height as the upper end of the third abutment holding section 41 (i.e., the lower position).

Figure 7 is a cross-sectional view showing an example of a wafer holding device in another embodiment of the present invention. Figure 7(a) shows the state in which the wafer W is supported at the upper position H in the second lifting mode. Figure 7(b) shows the state in which the wafer W is supported at the lower position L in the second lifting mode.

Specifically, when switching to the second lifting mode, the worker removes the second abutment support part 31 or the connecting part 33 of the second support part 3 from the rod 61 of the second lifting part 6, and performs an operation (e.g., a switch operation, etc.) to cause the control part 9 to execute the second lifting mode. On the other hand, when switching to the first lifting mode, the worker attaches the second abutment support part 31 or the connecting part 33 of the second support part 3 to the rod 61 of the second lifting part 6, and performs an operation (e.g., a switch operation, etc.) to cause the control part 9 to execute the first lifting mode.

(Modification)
In the above description, a configuration has been exemplified in which an operator manually switches between the first lifting mode and the second lifting mode by attaching and detaching the connecting portion 33 of the second support portion 3 .

However, in realizing the present invention, a configuration may be used in which the first lifting mode and the second lifting mode are automatically switched between while an operator attaches and detaches the connecting portion 33 of the second support portion 3 .
Specifically, the wafer holding device 1 has a structure in which the second support portion 3 is detachable, and includes a seating detection portion 7, and the second support portion is detachable.

The seat occupancy detector 7 detects the attachment state of the second support portion 3 .
Specifically, the occupancy detection unit 7 detects whether the second abutment portion 31 of the second support portion 3 and the connecting portion 33 to which the support pillar 32 are attached are attached at a predetermined position.
More specifically, as shown by dashed lines in FIGS. 1, 3 and 6 , the seat occupancy detection unit 7 is composed of an identification mark 71 , an image pickup camera 72 , an image processing device 73 , etc., and is connected to the control unit 9 .

The identification mark 71 is for determining whether the second support part 3 is attached at a predetermined position. Specifically, the identification mark 71 is provided on the connecting part 33 of the second support part 3. More specifically, the identification mark 71 can be, for example, a two-dimensional code or a predetermined pattern (which may be a marking or stamping).
The imaging camera 72 captures an image of the identification mark 71 and outputs the captured image to the outside.
The image processing device 73 processes the image captured by the imaging camera 72 and determines whether or not the identification mark 71 is included in the image.

Since the seat occupancy detection unit 7 is configured in this way, if the identification mark 71 is detected, it determines that the second support unit 3 is attached. On the other hand, if the identification mark 71 is not detected, it determines that the second support unit 3 is removed.

The control unit 9 is configured to select and execute either the first lifting mode or the second lifting mode depending on the attachment state of the second support unit 3 detected by the seat occupancy detection unit 7 .
Specifically, if the seat occupancy detection unit 7 determines that the second support unit 3 is attached, the control unit 9 executes the first lifting/lowering mode, and if the seat occupancy detection unit 7 determines that the second support unit 3 is detached, the control unit 9 executes the second lifting/lowering mode.

<Operation flow>
FIG. 8 is a flow diagram showing an example of an operational flow in another embodiment of the present invention.

First, the worker attaches or detaches the connecting portion 33 of the second support portion 3 and checks the attachment state (step s10). Then, if the second support portion 3 is attached, the control unit 9 executes the first lifting mode (steps s1 to s5) described above. On the other hand, if the second support portion 3 is detached, the control unit 9 executes the second lifting mode (steps s21 to s24) described below.

In the second lifting mode, if the wafer W can be received, the wafer holding device 1 switches the control unit 9 to the fourth support mode (upper stage position) and waits (step s21).

Then, the wafer W is placed (step s22) and the first support portion S1 of the wafer W is held by suction (step s23).

Then, the first lifting unit 5 is controlled to switch to the fifth support mode (lower position) (step s24). When switching from the fourth support mode (upper position) to the fifth support mode (lower position L), negative pressure is generated in the third support portion S3 to suction and hold the wafer W.

Then, the desired processing, inspection, etc. is executed (step s6), and it is determined whether the processing, etc. is completed (step s7). If the processing, etc. is not completed, the above-mentioned step s6 is continued, and if the processing, etc. is completed, the series of flows is terminated.

In this configuration, when holding a wafer that is prone to warping or deformation, the first lifting mode can be executed to hold the wafer securely. Furthermore, when holding a wafer that is not warped or deformed, the second lifting mode can be executed to hold the wafer quickly, which is preferable because it increases the number of wafers that can be processed per unit time.

In the above flow, a configuration in which an operator determines (manually determines) the installation state of the second support part 3 in step s10 has been exemplified. However, in step s10, the wafer holding device 1 may be configured to use the seating detection unit 7 to capture an image of the identification mark 71 with the imaging camera 72, and determine the presence or absence of the identification mark 71 with the image processing device 73 to determine (automatically determine) the installation state of the second support part 3.

In the above description, the seat occupancy detection unit 7 includes the identification mark 71, the imaging camera 72, and the image processing device 73, and the attachment state of the second support unit 3 is determined based on the presence or absence of the identification mark 71.
However, the seat occupancy detection unit 7 is not limited to this configuration, and may be configured to detect the attached/detached state of the connecting portion 33 by a sensor or the like, and switch between outputting an ON/OFF signal depending on the attached/detached state.

In the above, when switching from the fourth support mode (upper stage position) to the fifth support mode (lower stage position) in step s24, a configuration is exemplified in which a negative pressure is generated in the third support portion S3 to suction-hold the wafer W. This configuration is preferable because it ensures reliable holding of the wafer. However, if there is little warping or deformation of the wafer W and it can be reliably held, suction-holding by the first support portion S1 alone may be sufficient.

[Third embodiment]
In the above description, the embodiment in which the second support portion 3 is detached and the first lifting mode and the second lifting mode are selected and switched is shown as an example.
However, in realizing the present invention, the attachment and detachment of the second support part 3 and the provision of the second lifting and lowering mode are not essential configurations, and the present invention may have a "third lifting and lowering mode" in which the first support part 2 is switched between two positions, upper position H/lower position L, to lift and lower the wafer W while the second support part 3 is fixed at the lower position L, and the present invention may be configured to select and execute either the first lifting and lowering mode or the third lifting and lowering mode.

The third lifting mode has a sixth support mode and a seventh support mode, and switches from the sixth support mode to the seventh support mode while the wafer W received in the sixth support mode is held by suction. Note that the third lifting mode is performed with the second support part 3 attached (as shown in FIG. 2), similar to the first lifting mode.

In the sixth support mode, the upper end of the first support part is disposed at a height higher than the upper ends of the second support part 3 and the third support part 4 .
Specifically, in the sixth support mode, the height of the upper end of the second abutment holding portion 31 and the height of the upper end of the third abutment holding portion 41 are positioned at the same height (i.e., lower position L), and the actuator of the first lifting unit 5 is controlled to change the height at which the wafer W is supported and held so that the height of the upper end of the first abutment holding portion 21 is positioned at upper position H, which is higher than these.

The seventh support mode is a mode in which the upper end of the first support portion 3 is positioned at the same height as the upper ends of the second support portion 4 and the third support portion 4 (i.e., lower position L).
Specifically, in the seventh support mode, the actuator of the first lifting unit 5 is controlled to change the height at which the wafer W is supported and held so that the height of the upper end of the first abutment holding portion 21 is positioned at the same height as the upper ends of the second abutment holding portion 31 and the third abutment holding portion 41 (i.e., lower position L).

Figure 9 is a cross-sectional view showing an example of a wafer holding device in yet another embodiment of the present invention. Figure 9(a) shows the state in which the wafer W is supported at the upper position H in the third lifting mode. Figure 9(b) shows the state in which the wafer W is supported at the lower position L in the third lifting mode.

<Operation flow>
FIG. 10 is a flow diagram showing an example of an operational flow in yet another embodiment of the present invention.

First, with the connecting portion 33 of the second support portion 3 attached, the operator selects whether to use the first lifting mode or the third lifting mode to lift and lower the wafer W (step s15). The control portion 9 then determines which lifting mode has been selected (step s16), and if the first lifting mode has been selected, executes steps s1 to s5 as described above. On the other hand, if the third lifting mode has been selected, executes the third lifting mode (steps s31 to s34) described below.

In the third lifting mode, if the wafer W can be received, the wafer holding device 1 switches the control unit 9 to the sixth support mode (upper stage position) and waits (step s31).

Then, the wafer W is placed (step s32), and the first support portion S1 of the wafer W is held by suction (step s33).

Then, the first lifting unit 5 is controlled to switch to the seventh support mode (lower position) (step s34). When switching from the sixth support mode (upper position) to the seventh support mode (lower position), negative pressure is generated in the second support portion S2 and the third support portion S3 to suction and hold the wafer W.

Then, the desired processing, inspection, etc. is executed (step s6), and it is determined whether the processing, etc. is completed (step s7). If the processing, etc. is not completed, the above-mentioned step s6 is continued, and if the processing, etc. is completed, the series of flows is terminated.

In this configuration, when holding a wafer that is prone to warping or deformation, the first lifting mode can be executed to hold the wafer securely. Furthermore, when holding a wafer that is not warped or deformed, the third lifting mode can be executed to hold the wafer quickly, which is preferable because it increases the number of wafers that can be processed per unit time.

In the above flow, an example is given of a configuration in which in step s15 the operator selects whether to lift or lower the wafer W in the first lifting mode or the third lifting mode, and in step s16 it is determined which lifting mode has been selected.
However, whether to execute the first lifting/lowering mode or the third execution mode may be selected by an operator's operation, or may be registered in association with type information (so-called recipe file, etc.) of the wafer W to be handled, and the control unit 9 may receive the recipe information in step s15 and determine the lifting/lowering mode in step s16. In other words, the operator may determine whether to use the first lifting/lowering mode or the third lifting/lowering mode depending on the type of the wafer W to be held (i.e., whether it is easily deformed), or the lifting/lowering mode may be automatically switched based on a recipe file registered in advance.

If the control unit 9 is configured to automatically switch the lifting mode, this is preferable because it saves the worker the trouble of attaching and detaching the second support unit 3. Furthermore, this is even more preferable because it prevents the worker from setting the lifting mode incorrectly.

In the above, when switching from the sixth support mode (upper stage position) to the seventh support mode (lower stage position) in step s34, a configuration has been exemplified in which negative pressure is generated in the second support portion S2 and the third support portion S3 to suction-hold the wafer W. This configuration is preferable because it ensures reliable holding of the wafer. However, if there is little warping or deformation of the wafer W and it can be reliably held, suction-holding by the first support portion S1 alone may be sufficient.

In the above, an example has been given of a configuration in which the second support portion 3 is fixed in the lower position L, but the present invention is not limited to this configuration. A configuration in which the first support portion 2 and the second support portion 3 are raised and lowered in conjunction with each other, and both the first abutment holding portion 21 and the third abutment holding portion 41 are switched between the upper position H and the lower position L, may also be used.
In the above description, the control unit 9 has been exemplified as having the first lifting mode, and the second or third lifting mode, but the control unit 9 may have the first lifting mode, the second lifting mode, and the third lifting mode, and may execute the second lifting mode by a change of setup or operation by an operator, execute the third lifting mode by an operation by an operator, or automatically execute the third lifting mode based on the type information of the wafer W. Specifically, a configuration can be exemplified in which, after it is determined that the second support unit 3 is attached in step s11 of the operation flow shown in Fig. 8, the operation flow shown in Fig. 10 (steps s15 and thereafter) is executed.

REFERENCE SIGNS LIST 1 wafer holding device 2 first support section 3 second support section 4 third support section 5 first lift section 6 second lift section 7 occupancy detection section 8 negative pressure suction section 9 control section 21 first contact holding section 22 support column 23 connecting member 31 second contact holding section 32 support column 33 connecting member 41 third contact holding section 42 support column 43 connecting member 51 rod 52 main body 61 rod 62 main body 71 identification mark 72 imaging camera 73 image processing device W wafer R contact allowable area S1 first support portion S2 second support portion S3 third support portion

Claims (8)

A wafer holding device that receives a wafer in a horizontal state and holds it in a predetermined position,
A first support part that supports from below a first support portion that is set in at least three places in a contact allowable region set in a lower part of the outer periphery of the wafer so as to surround the center of the wafer;
a second support portion that supports, from below, a second support portion that is set at a position that fills the gap between the first support portions in the contact allowable region;
a third support portion that supports, from below, a third support region that is set at a position that fills the gap between the first support portion and the second support portion in the contact allowable region;
a first lifting unit that changes a relative height between an upper end of the first support unit and an upper end of the second support unit;
a second lifting unit that changes a relative height between an upper end of the second support unit and an upper end of the third support unit;
a negative pressure suction unit that generates a negative pressure in the first support portion to suction and hold the wafer;
a control unit that controls a change in the relative height of the first lifting unit and the second lifting unit and a switching between suction hold and release by the negative pressure suction unit,
The control unit is
a first support mode in which an upper end of the first support portion is disposed above a height of an upper end of the second support portion and an upper end of the third support portion;
a second support mode in which an upper end of the first support portion and an upper end of the second support portion are disposed at the same height above an upper end of the third support portion;
a third support mode in which the height of an upper end of the first support portion and the height of an upper end of the second support portion are disposed at the same height as the height of an upper end of the third support portion;
a wafer holding device which switches from the first support mode to the second support mode while suction-holding the wafer received in the first support mode, and then switches to the third support mode. The wafer holding device according to claim 1, characterized in that the third support portion is set in an arc shape that follows the outer edge shape of the wafer to be held. The wafer holding device according to claim 1 or 2, characterized in that the negative pressure suction unit also generates a negative pressure in the second support portion to suction and hold the wafer. The wafer holding device according to claim 3, characterized in that the negative pressure suction unit also generates a negative pressure in the third support portion to suction and hold the wafer. A wafer holding device that receives a wafer in a horizontal state and holds it in a predetermined position,
A first support part that supports from below a first support portion that is set in at least three places in a contact allowable region set in a lower part of the outer periphery of the wafer so as to surround the center of the wafer;
a second support portion that supports, from below, a second support portion that is set at a position that fills the gap between the first support portions in the contact allowable region;
a third support portion that supports, from below, a third support region that is set at a position that fills the gap between the first support portion and the second support portion in the contact allowable region;
a first lifting unit that changes a relative height between an upper end of the first support unit and an upper end of the second support unit;
a second lifting unit that changes a relative height between an upper end of the second support unit and an upper end of the third support unit;
a negative pressure suction unit that generates a negative pressure in the first support portion to suction and hold the wafer;
a control unit that controls a change in the relative height of the first lifting unit and the second lifting unit and a switching between suction hold and release by the negative pressure suction unit,
The control unit has at least a first lifting mode and a second lifting mode,
The first lifting mode is
a first support mode in which an upper end of the first support portion is disposed above a height of an upper end of the second support portion and an upper end of the third support portion;
a second support mode in which an upper end of the first support portion and an upper end of the second support portion are disposed at the same height above an upper end of the third support portion;
a third support mode in which the height of an upper end of the first support portion and the height of an upper end of the second support portion are disposed at the same height as the height of an upper end of the third support portion;
While holding the wafer received in the first support mode by suction, the first support mode is switched to the second support mode, and then the third support mode is switched to;
The second lifting mode is
a fourth support mode in which an upper end of the first support portion is disposed above a height of an upper end of the third support portion;
a fifth support mode in which a height of an upper end of the first support portion is the same as a height of an upper end of the third support portion;
switching from the fourth support mode to the fifth support mode while suction-holding the wafer received in the fourth support mode;
The wafer holding device, wherein the control unit selects and executes either the first lifting mode or the second lifting mode. The second support portion has a detachable structure,
an occupancy detection unit that detects an attachment state of the second support unit;
The control unit is
When the seat occupancy detection unit detects that the second support unit is attached, the first lifting mode is executed;
6. The wafer holding device according to claim 5, wherein the second lifting mode is executed when the presence detector detects that the second support part has been removed. A wafer holding device that receives a wafer in a horizontal state and holds it in a predetermined position,
A first support part that supports from below a first support portion that is set in at least three places in a contact allowable region set in a lower part of the outer periphery of the wafer so as to surround the center of the wafer;
a second support portion that supports, from below, a second support portion that is set at a position that fills the gap between the first support portions in the contact allowable region;
a third support portion that supports, from below, a third support region that is set at a position that fills the gap between the first support portion and the second support portion in the contact allowable region;
a first lifting unit that changes a relative height between an upper end of the first support unit and an upper end of the second support unit;
a second lifting unit that changes a relative height between an upper end of the second support unit and an upper end of the third support unit;
a negative pressure suction unit that generates a negative pressure in the first support portion to suction and hold the wafer;
a control unit that controls a change in the relative height of the first lifting unit and the second lifting unit and a switching between suction hold and release by the negative pressure suction unit,
The control unit has at least one lifting mode and a third lifting mode,
The first lifting mode is
a first support mode in which an upper end of the first support portion is disposed above a height of an upper end of the second support portion and an upper end of the third support portion;
a second support mode in which an upper end of the first support portion and an upper end of the second support portion are disposed at the same height above an upper end of the third support portion;
a third support mode in which the height of an upper end of the first support portion and the height of an upper end of the second support portion are disposed at the same height as the height of an upper end of the third support portion;
While holding the wafer received in the first support mode by suction, the first support mode is switched to the second support mode, and then the third support mode is switched to;
The third lifting mode is
a sixth support mode in which the upper end of the first support portion is disposed above a height higher than an upper end of the second support portion and an upper end of the third support portion;
a seventh support mode in which the height of an upper end of the first support portion is the same as the height of an upper end of the second support portion and an upper end of the third support portion;
switching from the sixth support mode to the seventh support mode while suction-holding the wafer received in the sixth support mode;
6. The wafer holding device according to claim 5, wherein the control unit selects and executes either the first lifting mode or the third lifting mode. The wafer holding device according to any one of claims 5 to 7, characterized in that the negative pressure suction unit also generates a negative pressure in the third support portion to suction and hold the wafer.

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