Wafer holding apparatus and wafer holding method

Abstract

The present invention provides a wafer holding device that can move wafers vertically and hold them on a bonding stage with a simple configuration. [Solution] The bonding stage 10, the lifter 20, the clamper 30, the slider 40 that moves the lifter 20 and the clamper 30 relative to each other, and the base portion 40A which has a spring 35 that applies a predetermined pressing force to the clamper 30.

Description

Technical Field

[0001] The present disclosure relates to a structure and a holding method of a wafer holding device that holds a wafer on a mounting surface of a bonding stage.

Background Art

[0002] A substrate holding device for holding a wafer is used. For example, Patent Document 1 discloses a substrate holding device including a substrate support portion and a substrate pressing portion offset outward from the substrate support portion, and by lowering the substrate pressing portion, the outer peripheral portion of the wafer is pressed against the upper end of the substrate support portion to hold the wafer.

[0003] Also, a wafer fixing device for fixing a wafer with a warped peripheral portion is used. For example, Patent Document 2 discloses that in an exposure device for manufacturing a semiconductor, the outer peripheral portion of a wafer with a warped peripheral portion is press-fixed onto a mounting member by a clamp mechanism, and exposure is performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in recent years, a bonding device for bonding a plurality of other semiconductor chips in multiple stages on a semiconductor chip formed on a wafer has been used. In such a bonding device, a wafer is placed on a bonding stage by a lifter, and the wafer is vacuum-sucked onto the bonding stage.

[0006] However, when a semiconductor chip is bonded onto a wafer, the wafer warps, making it impossible to vacuum-suction the wafer even when it is placed on the bonding stage. For this reason, adding a clamping mechanism as described in Patent Documents 1 and 2 could be considered, but this would complicate the structure.

[0007] Therefore, the present disclosure aims to provide a wafer holding device that can move a wafer vertically and hold it on a bonding stage with a simple configuration. [Means for solving the problem]

[0008] The wafer holding device of this disclosure is characterized by comprising: a bonding stage that vacuum-adsorbs a wafer placed on a mounting surface; a lifter that supports the wafer from below above the bonding stage and is housed within the bonding stage; a clamper positioned above the lifter and pressing the outer periphery of the wafer placed on the mounting surface against the mounting surface; and a base portion having a slider that moves the clamper relative to the lifter and a spring that applies a predetermined pressing force to the clamper.

[0009] This allows the lifter to be lowered and the wafer to be pressed by the clamper by lowering the slider. Therefore, the wafer can be moved vertically and held on the bonding stage with a simple configuration.

[0010] In the wafer holding device of the present disclosure, the slider is capable of supporting the lifter and the clamper from below and is movable in the vertical direction, and the spring is disposed between the slider and the clamper, and when the slider is lowered by a predetermined height, the spring is compressed, and the clamper may apply the pressing force to the outer periphery of the wafer.

[0011] This allows for the vertical movement of the wafer and its retention on the bonding stage with a simple configuration.

[0012] In the wafer holding device of the present disclosure, the lifter comprises a lifter base and a support arm provided above the lifter base to support the wafer from below, the clamper comprises a clamper base and a pressing plate provided above the clamper base to cover the outer periphery of the wafer, the pressing plate being positioned above the support arm, the slider comprises an upper plate supporting the bottom surface of the lifter base, a plurality of pins protruding downward from the lower surface of the upper plate, and a lower plate attached to the lower ends of the plurality of pins to support the bottom surface of the clamper base, and the spring may be positioned between the lower surface of the upper plate and the upper surface of the clamper base.

[0013] In this configuration, the upper plate of the slider supports the bottom surface of the lifter base, the lower plate of the slider supports the bottom surface of the clamper base, and a spring is placed between the upper and lower plates. By lowering the slider using a drive unit, the lifter can be lowered and the wafer can be pressed by the clamper. Furthermore, since the biasing force of the spring presses the pressing plate against the outer edge of the wafer, damage to the wafer due to excessive force can be suppressed.

[0014] In the wafer holding apparatus of the present disclosure, the lifter includes left and right lifter bases arranged along the left and right sides of the bonding stage, at least one left and right lifter column extending upward from the left and right lifter bases, and at least one left and right support arm extending from the upper ends of the left and right lifter columns to above the bonding stage and supporting the wafer from below, and the clamper may include left and right clamper bases arranged along the left and right sides of the bonding stage, at least one left and right clamper column extending upward from the left and right clamper bases, and a pressing plate attached to the upper ends of the left and right clamper columns and covering the outer periphery of the wafer.

[0015] This allows the wafer to be held from both sides and pressed evenly against the mounting surface.

[0016] In the wafer holding apparatus of the present disclosure, the bonding stage may include at least one left and right groove for accommodating the left and right support arms.

[0017] This allows the wafer to be placed on the mounting surface of the bonding stage with a simple configuration.

[0018] The wafer holding device of this disclosure includes a bonding stage that vacuum-adsorbs a wafer placed on a mounting surface, a lifter that supports the wafer from below above the bonding stage and is housed within the bonding stage, a clamper positioned above the lifter and pressing the outer periphery of the wafer placed on the mounting surface against the mounting surface, a base portion having a slider that moves the clamper relative to the lifter and a spring that applies a predetermined pressing force to the clamper, a drive unit that moves the slider in the vertical direction, and The device comprises a control unit for adjusting the operation of the drive unit, wherein the control unit is configured to lower the slider using the drive unit until the wafer supported by the lifter contacts the aforementioned mounting surface, to further lower the slider using the drive unit until the clamp contacts the outer periphery of the wafer, to further lower the slider using the drive unit to a predetermined height to compress the spring, and to press the outer periphery of the wafer against the aforementioned mounting surface of the bonding stage using the clamp.

[0019] This allows the drive unit to lower the slider, thereby lowering the lifter and pressing the wafer with the clamper. As a result, the wafer can be moved vertically and held on the bonding stage with a simple configuration.

[0020] The wafer holding method of the present disclosure is a wafer holding method for holding a wafer with a warped outer peripheral portion on a bonding stage, including a bonding stage for vacuum-sucking the wafer placed on a placement surface, a lifter that supports the wafer from below above the bonding stage and is stored in the bonding stage, a clamper that is disposed above the lifter and presses the outer peripheral portion of the wafer placed on the placement surface against the placement surface, a base portion having a slider that relatively moves the clamper with respect to the lifter and a spring that applies a predetermined pressing force to the clamper, a preparation step of preparing a wafer holding device including the base portion, a first lowering step of lowering the slider until the wafer supported by the lifter abuts on the placement surface, a second lowering step of further lowering the slider until the clamper abuts on the outer peripheral portion of the wafer, and a pressing step of further lowering the slider by a predetermined height to compress the spring and pressing the outer peripheral portion of the wafer against the placement surface of the bonding stage by the clamper.

[0021] Thereby, a warped wafer can be easily held on the bonding stage.

Advantages of the Invention

[0022] The vertical movement of the wafer and the holding on the bonding stage can be performed with a simple configuration.

Brief Description of the Drawings

[0023] [Figure 1] It is a plan view showing the configuration of the wafer holding device of the embodiment. [Figure 2] It is a right side view showing the configuration of the wafer holding device of the embodiment. [Figure 3] It is a right side view schematically showing the configuration of the wafer holding device of the embodiment. [Figure 4] It is a cross-sectional view schematically showing the configuration of the wafer holding device of the embodiment, which is a cross-section taken along the line A-A in FIG. 3. [Figure 5]This is a schematic right side view illustrating the operation of the wafer holding device of the embodiment, and is an explanatory diagram showing the state in which the wafer is placed on the mounting surface of the bonding stage. [Figure 6] This is a schematic cross-sectional view illustrating the operation of the wafer holding device of the embodiment, and is the BB cross-section in Figure 5. [Figure 7] This is a schematic right side view illustrating the operation of the wafer holding device of the embodiment, and is an explanatory diagram showing the state in which the clamper is in contact with the wafer. [Figure 8] This is a schematic cross-sectional view illustrating the operation of the wafer holding device of the embodiment, and is the CC cross-section in Figure 6. [Figure 9] This is a schematic right side view illustrating the operation of the wafer holding device according to the embodiment, and is an explanatory diagram showing the state in which the spring is compressed and the clamp is pressing against the peripheral part of the wafer. [Figure 10] This is a schematic cross-sectional view illustrating the operation of the wafer holding device of the embodiment, and is the DD cross-section in Figure 8. [Modes for carrying out the invention]

[0024] The wafer holding device 100 of the embodiment will be described below with reference to the drawings. In the following description, the side where the drive motor 51 is located will be referred to as the rear side of the wafer holding device 100, and the opposite side as the front side. FR, UP, and LH shown in each figure indicate the front, top, and left sides of the wafer holding device 100, respectively. The opposite directions of FR, UP, and LH indicate the rear, bottom, and right sides. When the directions front / back, left / right, and up / down are simply used, they refer to the front / back, left / right, and up / down of the wafer holding device 100, respectively, unless otherwise specified.

[0025] As shown in Figures 1 and 2, the wafer holding device 100 includes a bonding stage 10, a lifter 20, a clamper 30, a slider 40, a coil spring 35 (see Figures 3 and 4), a drive unit 50, a frame 60, and a control unit 70. The slider 40 and the coil spring 35 constitute the base unit 40A.

[0026] The frame 60 is a substrate on which the bonding stage 10 and other components are mounted. The bonding stage 10 is mounted on the frame 60. The bonding stage 10 holds the wafer 80 on its upper mounting surface 11. The mounting surface 11 is provided with a plurality of vacuum holes 12. The vacuum holes 12 are connected to a vacuum device (not shown). By creating a vacuum in the vacuum holes 12 using the vacuum device, the wafer 80 can be vacuum-adsorbed to the mounting surface 11. The mounting surface 11 is provided with a plurality of grooves 13 extending from the left and right sides toward the center. The grooves 13 accommodate the support arms 23 of the lifter 20, which will be described later.

[0027] The following describes the right-side lifter 20, the right-side portion of the clamper 30, the right-side slider 40, and the right-side drive unit 50 of the wafer holding device 100, referring to Figures 3 and 4. The left-side lifter 20, the left-side portion of the clamper 30, the left-side slider 40, and the left-side drive unit 50 are symmetrical to the right-side parts, so their description will be omitted.

[0028] As shown in Figures 3 and 4, the lifter 20 is a member that supports the wafer 80 from below above the bonding stage 10. The lifter 20 comprises a lifter base 21, front and rear lifter columns 22, and front and rear support arms 23. The lifter base 21 is a rectangular parallelepiped member that is long in the front-to-back direction and is positioned along the right side of the bonding stage 10. The lifter columns 22 are longitudinal members that extend upward from the lifter base 21. The front and rear lifter columns 22 are positioned at the front and rear ends of the lifter base 21. The front and rear support arms 23 are strip-shaped members that extend from the upper ends of the front and rear lifter columns 22 to the mounting surface 11 of the bonding stage 10.

[0029] As shown in Figures 3 and 4, the clamper 30 comprises a clamper base 31, front and rear clamper columns 32, and a pressing plate 33. The clamper base 31 is a rectangular parallelepiped member that is long in the front-to-back direction and positioned along the right side of the bonding stage 10. The clamper columns 32 are longitudinal members that extend upward from the clamper base 31. The front and rear clamper columns 32 are positioned at the front and rear ends of the clamper base 31. The pressing plate 33 is a square flat plate member that is attached to the upper ends of the front and rear clamper columns 32 on the right side and the front and rear clamper columns 32 on the left side. The pressing plate 33 is positioned above the support arm 23 of the lifter 20. As shown in Figure 1, the pressing plate 33 has a circular hole 34 with a diameter slightly smaller than the diameter of the wafer 80. The periphery of the circular hole 34 covers the outer circumference of the wafer 80 placed on the mounting surface 11 of the bonding stage 10.

[0030] As shown in Figures 3 and 4, the slider 40 is a component fixed to the frame 60 and movable vertically guided by a guide rail 49 extending upward from the frame 60. The slider 40 comprises an upper plate 41, a pin 42, a lower plate 43, a sliding plate 46, and a drive roller 47.

[0031] The slide plate 46 is a plate member that is guided by the guide rail 49 and can move in the vertical direction. A drive roller 47 is attached to the right side of the slide plate 46. The drive roller 47 is rotatable around the rotating shaft 48. The drive roller 47 engages with the elongated hole 55 of the second link 53 of the drive unit 50, which will be described later.

[0032] The upper plate 41 is a plate-shaped member attached to the upper end of the slide plate 46. The upper plate 41 has ribs 44 that protrude downward. The ribs 44 are fixed to the right side of the slide plate 46 with bolts 45. The upper surface of the upper plate 41 is a flat plane. The pins 42 are longitudinal members attached to the left side of the upper plate 41 and extending downward. The pins 42 are located at the front and rear ends of the upper plate 41. The lower plate 43 is a plate member that extends in the front-rear direction and is connected to the lower ends of the front and rear pins 42.

[0033] The bottom surface of the lifter base 21 rests on the top surface of the upper plate 41. The bottom surface of the clamper base 31 rests on the top surface of the lower plate 43. As a result, the top surface of the upper plate 41 supports the bottom surface of the lifter base 21 from below, allowing it to move toward and away from it. The top surface of the lower plate 43 also supports the bottom surface of the clamper base 31 from below, allowing it to move toward and away from it.

[0034] The front and rear coil springs 35 are positioned between the lower surface of the upper plate 41 and the upper surface of the clamper base 31 so as to be coaxial with the front and rear pins 42. When the coil springs 35 are compressed, they apply a pressing force to the clamper 30.

[0035] As shown in Figures 1 and 2, the drive unit 50 consists of a motor 51, a first link 52 positioned at the rear, a second link 53 positioned at the front, and a third link 54 connecting the first link 52 and the third link 54 in the front-rear direction. As shown in Figure 2, the first link 52 is a plate member mounted on the frame 60 so as to be rotatable around a rotating shaft 52A. The rotating shaft 52B is attached to the front end of the first link 52. The third link 54 is a plate member mounted on the frame 60 so as to be rotatable at its lower end so as to be rotatable around a rotating shaft 54A. The rotating shaft 54B is attached to the upper end of the third link 54. The rear end of the second link 53 is rotatably mounted around the rotating shaft 52B of the first link 52, and the front end of the second link 53 is rotatably mounted around the rotating shaft 54B. An elongated hole 55 is provided in the center of the second link 53, into which the drive roller 47 of the slider 40 engages.

[0036] The motor 51 is connected to the control unit 70 and operates according to commands from the control unit 70. The control unit 70 is a computer equipped with a CPU 71, which is a processor that performs information processing, and a memory 72 that stores control programs and control data.

[0037] Next, we will describe the operation of the wafer holding device 100 configured as described above. First, we will describe the operation of the drive unit 50 with reference to Figure 2.

[0038] When the motor 51 rotates and the first link 52 rotates counterclockwise as indicated by arrow 91 in Figure 2, the second link 53 moves backward as indicated by arrow 92 in Figure 2. At the same time, the third link 54 rotates as indicated by arrow 93 and its upper end moves upward. As a result, the second link 53 moves upward as indicated by arrow 94 in Figure 2. Then, the elongated hole 55 of the second link 53 moves upward, causing the slider 40 to move the drive roller 47 upward. As a result, the slider 40 moves upward. Conversely, when the motor 51 rotates the first link 52 clockwise, the second link 53 moves forward, the elongated hole 55 moves downward, and the slider 40 moves downward.

[0039] Next, referring to Figures 3 to 10, the operation of vacuum adsorption of the warped wafer 80 onto the mounting surface 11 of the bonding stage 10 will be described.

[0040] Figures 3 and 4 show the state in which the lifter 20 and clamper 30 have been raised to their highest positions. A curved wafer 80 with a semiconductor chip bonded to its upper surface is placed on the support arm 23 of the lifter 20 by a robot arm or the like (not shown) (preparation step).

[0041] Next, the control unit 70 rotates the motor 51, causing the slider 40 to descend via the first link 52, second link 53, and third link 54. As the slider 40 descends, the upper plate 41 and lower plate 43 of the slider 40 move downward together, as shown in Figures 5 and 6. Then, the lifter 20 supported on the upper surface of the upper plate 41 and the clamper 30 supported on the upper surface of the lower plate 43 descend together with the slider 40. When the support arm 23 of the lifter 20 is housed in the groove 13 of the bonding stage 10, the wafer 80 comes into contact with the mounting surface 11 of the bonding stage 10. In this way, the control unit 70 causes the slider 40 to descend via the drive unit 50 until the wafer 80 comes into contact with the mounting surface 11 of the bonding stage 10 (first descending step). Note that in this state, the outer periphery of the warped wafer 80 is not in contact with the mounting surface 11.

[0042] Subsequently, when the control unit 70 lowers the slider 40 with the motor 51, the lower end of the support arm 23 of the lifter 20 comes into contact with the bottom surface of the groove 13 of the bonding stage 10. As a result, the lifter 20 can no longer descend. Then, when the control unit 70 lowers the slider 40 further with the motor 51, as shown in Figures 7 and 8, the lifter base 21 separates from the upper surface of the upper plate 41 of the slider 40. At this time, since the clamper base 31 is supported by the upper surface of the lower plate 43 of the slider 40, the clamper 30 descends together with the slider 40. In this way, the clamper 30 moves relative to the lifter 20 in the vertical direction. Then, the peripheral edge of the round hole 34 of the pressing plate 33 of the clamper 30 comes into contact with the outer circumference of the warped wafer 80. In this manner, the control unit 70 further lowers the slider 40 using the drive unit 50 until the pressing plate 33 of the clamper 30 contacts the outer periphery of the warped wafer 80 (second lowering step).

[0043] When the pressing plate 33 contacts the outer periphery of the wafer 80, the clamper 30 can no longer descend. Then, when the control unit 70 further lowers the slider 40 with the motor 51, as shown in Figures 9 and 10, the bottom surface of the clamper base 31 separates from the top surface of the lower plate 43 of the slider 40. The lower plate 43 of the slider 40 then begins to compress the coil spring 35. When the control unit 70 lowers the slider 40 to a predetermined height with the motor 51, the coil spring 35 is compressed by a predetermined length. The coil spring 35 then biases the clamper base 31 downward. As a result, the pressing plate 33 of the clamper 30 presses against the outer periphery of the warped wafer 80, bringing it closer to or in contact with the mounting surface 11 of the bonding stage 10 (pressing process).

[0044] As a result, the gap between the wafer 80 and the mounting surface 11 becomes smaller, and air leakage from between the wafer 80 and the mounting surface 11 is reduced. Therefore, when the vacuum hole 12 of the bonding stage 10 is evacuated, the warped wafer 80 is vacuum-adhered to the mounting surface 11.

[0045] When removing the wafer 80 from the bonding stage 10, the control unit 70 drives the motor 51 to raise the slider 40, the coil spring 35 stretches and returns to its original length, and when the upper surface of the lower plate 43 contacts the bottom surface of the clamper base 31, the clamper 30 begins to rise. Then, when the upper surface of the upper plate 41 contacts the bottom surface of the lifter base 21, the lifter 20 rises.

[0046] As described above, in the wafer holding device 100 of this embodiment, the upper plate 41 of the slider 40 supports the bottom surface of the lifter base 21, the lower plate 43 of the slider 40 supports the bottom surface of the clamper base 31, and a coil spring 35 is placed between the upper plate 41 and the lower plate 43, so that the clamper 30 can move relative to the lifter 20 in the vertical direction. As a result, by lowering the slider 40 with the drive unit 50, the lifter 20 can be lowered and the outer periphery of the wafer 80 can be pressed by the clamper 30. This makes it possible to move the wafer 80 in the vertical direction and hold the wafer 80 on the bonding stage 10 with a simple configuration.

[0047] Furthermore, in the embodiment, the wafer holding device 100 presses the pressing plate 33 against the outer periphery of the warped wafer 80 by the pressing force applied by the coil spring 35, thereby suppressing damage to the wafer 80 caused by a large force being applied to the wafer 80.

[0048] In the above description, the lifter 20 was described as comprising two lifter columns 22 and two support arms 23, but it is not limited to this. For example, multiple support arms 23 may be attached to the front and rear lifter columns 22, or multiple support arms 23 may be attached to a single lifter column 22. Similarly, the clamper column 32 may consist of three columns instead of two, or it may consist of just one. Likewise, the slider 40 was described as comprising two pins 42 and two coil springs 35, but it is not limited to this. It may consist of three or more pins 42 and multiple coil springs 35, or it may consist of one pin 42 and one coil spring 35.

[0049] Furthermore, although the above description assumes that the lifter base 21 and clamper base 31 are rectangular parallelepipeds, they may be flat or have other shapes as long as they can be supported by the upper surface of the upper plate 41 and the upper surface of the lower plate 43 of the slider 40. Similarly, the upper plate 41 and lower plate 43 are not limited to flat plates as long as they can support the lifter base 21 and clamper base 31 from below. For example, the upper plate 41 and lower plate 43 may be cylindrical, and the lifter base 21 and clamper base 31 may be semi-cylindrical. Alternatively, the upper plate 41 and lower plate 43 may be longitudinal members with a square cross-section, and the lifter base 21 and clamper base 31 may be groove-shaped members with an open bottom.

[0050] Furthermore, although the above explanation assumes the use of a coil spring 35, the system is not limited to a coil spring 35 and may be constructed using other elastic members as long as a biasing force can be applied to the pressure plate 33. [Explanation of Symbols]

[0051] 10 Bonding stage, 11 Mounting surface, 12 Vacuum hole, 13 Groove, 20 Lifter, 21 Lifter base, 22 Lifter column, 23 Support arm, 30 Clamper, 31 Clamper base, 32 Clamper column, 33 Pressing plate, 34 Round hole, 35 Coil spring, 40 Slider, 40A Base section, 41 Upper plate, 42 Pin, 43 Lower plate, 44 Rib, 45 Bolt, 46 Slide plate, 47 Drive roller, 48 Rotating shaft, 49 Guide rail, 50 Drive unit, 51 Motor, 52A, 52B, 54A, 54B Rotating shaft, 55 Slotted hole, 60 Frame, 70 Control unit, 71 CPU, 72 Memory, 80 Wafer, 100 Wafer holding device.

Claims

1. A bonding stage that vacuum-adsorbs the wafer placed on the mounting surface, A lifter supports the wafer from below above the bonding stage and is housed within the bonding stage, A clamper is positioned above the lifter and presses the outer periphery of the wafer, which is placed on the aforementioned mounting surface, against the aforementioned mounting surface, The system comprises a base portion having a slider that moves the clamp relative to the lifter and a spring that applies a predetermined pressing force to the clamp. A wafer holding device characterized by the following.

2. A wafer holding device according to claim 1, The slider is capable of supporting the lifter and the clamper from below and is movable in the vertical direction. The spring is positioned between the slider and the clamper. When the slider is lowered to a predetermined height, the spring is compressed, and the clamper applies the pressing force to the outer periphery of the wafer. A wafer holding device characterized by the following.

3. A wafer holding device according to claim 2, The lifter comprises a lifter base and a support arm provided above the lifter base to support the wafer from below. The clamper comprises a clamper base and a pressing plate provided above the clamper base and covering the outer periphery of the wafer. The pressing plate is positioned above the support arm, The slider comprises an upper plate that supports the bottom surface of the lifter base, a plurality of pins that protrude downward from the lower surface of the upper plate, and a lower plate attached to the lower ends of the plurality of pins that supports the bottom surface of the clamper base. The spring is positioned between the lower surface of the upper plate and the upper surface of the clamp base. A wafer holding device characterized by the following.

4. A wafer holding device according to claim 3, The lifter includes left and right lifter bases arranged along the left and right sides of the bonding stage, at least one left and right lifter column extending upward from the left and right lifter bases, and at least one left and right support arm extending from the upper ends of the left and right lifter columns to above the bonding stage and supporting the wafer from below. The clamper includes left and right clamper bases arranged along the left and right sides of the bonding stage, at least one left and right clamper column extending upward from the left and right clamper bases, and a pressing plate attached to the upper ends of the left and right clamper columns to cover the outer periphery of the wafer. A wafer holding device characterized by the following.

5. A wafer holding device according to claim 4, The bonding stage is provided with at least one left and right groove for accommodating the left and right support arms. A wafer holding device characterized by the following.

6. A bonding stage that vacuum-adsorbs the wafer placed on the mounting surface, A lifter supports the wafer from below above the bonding stage and is housed within the bonding stage, A clamper is positioned above the lifter and presses the outer periphery of the wafer, which is placed on the aforementioned mounting surface, against the aforementioned mounting surface, A base portion having a slider that moves the clamper relative to the lifter and a spring that applies a predetermined pressing force to the clamper, A drive unit for moving the slider in the vertical direction, The system includes a control unit for adjusting the operation of the drive unit, The control unit, The slider is lowered by the drive unit until the wafer supported by the lifter contacts the aforementioned mounting surface. The drive unit further lowers the slider until the clamp contacts the outer periphery of the wafer. The drive unit further lowers the slider by a predetermined height, compressing the spring, and the clamper is configured to press the outer periphery of the wafer against the aforementioned surface of the bonding stage. A wafer holding device characterized by the following.

7. A wafer holding method for holding a wafer with a warped outer edge on a bonding stage, Preparation steps for preparing a wafer holding device comprising: a bonding stage for vacuum adsorption of the wafer placed on a mounting surface; a lifter that supports the wafer from below above the bonding stage and is housed within the bonding stage; a clamper positioned above the lifter and pressing the outer periphery of the wafer placed on the mounting surface against the mounting surface; and a base portion having a slider for relative movement of the clamper with respect to the lifter and a spring for applying a predetermined pressing force to the clamper; A first lowering step involves lowering the slider until the wafer supported by the lifter contacts the aforementioned mounting surface, A second lowering step involves further lowering the slider until the clamp contacts the outer periphery of the wafer, A pressing step is performed in which the slider is lowered further by a predetermined height to compress the spring, and the outer periphery of the wafer is pressed against the aforementioned surface of the bonding stage by the clamper. A wafer holding method characterized by including

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