Wafer holding device

Abstract

To provide a wafer holding device capable of eliminating water remaining in a portion where a wafer is held by claws and reducing chuck marks during drying after cleaning.SOLUTION: In a wafer holding device for cleaning and drying a wafer W by holding and rotating the peripheral edge of the wafer W with a plurality of claws 14, each of the claws 14 includes a first restricting portion 14A that restricts the movement of the wafer W in the horizontal direction, a second restricting portion 14B that restricts upward movement of the wafer W, and a third restricting portion 14C that restricts the downward movement of the wafer W, and at least one of the first restricting portion 14A, the second restricting portion 14B, and the third restricting portion 14C is arranged so as to be shifted in the circumferential direction of the wafer W.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present invention relates to a wafer holding device, and more particularly to a wafer holding device that holds and rotates the peripheral edge of a wafer with a plurality of claw portions.

Background Art

[0003] <{0000012}}This CMP apparatus incorporates a spin processing apparatus that places the polished wafer on a turntable, rotates it at high speed while supplying a cleaning liquid to clean the wafer, and after cleaning, rotates the wafer at high speed while supplying dry air to dry the wafer (see, for example, Patent Document 1).

[0004] The spin processing apparatus includes a wafer holding device that places a wafer on a turntable, grips three to four locations on the peripheral edge of the placed wafer with claw portions (clamps), and rotates integrally with the wafer. The claw portions of this wafer holding device grip the wafer and rotate the wafer at high speed. Therefore, the contact locations of the clamps where the claw portions grip the peripheral edge of the wafer are always at the same position.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, a technical problem arises that needs to be solved in order to provide a wafer holding device that can eliminate water remaining at the point where the wafer is gripped by the claws during the drying process after washing, thereby reducing chuck marks. The present invention aims to solve this problem. [Means for solving the problem]

[0008] The present invention was proposed to achieve the above objective, and the invention described in claim 1 is a wafer holding device that grips the peripheral edge of a wafer with a plurality of claws and rotates it to wash and dry the wafer with water, wherein each claw comprises a first restricting portion that restricts the horizontal movement of the wafer, a second restricting portion that restricts the upward movement of the wafer, and a third restricting portion that restricts the downward movement of the wafer, and at least one of the first to third restricting portions is arranged offset in the circumferential direction of the wafer.

[0009] With this configuration, at least one of the three restricting parts—the first, second, and third—restricts the horizontal and vertical movement of the wafer, allowing it to be gripped and cleaned. Furthermore, by arranging each restricting part offset in the circumferential direction of the wafer, the contact area between each restricting part and the wafer on the gripping claws is divided and reduced. This reduces the amount of water that accumulates at each location, and the surface tension of the water at each location decreases. Therefore, when the claws rotate with the wafer during drying, the water accumulated at each location where the claws grip the wafer is easily ejected from the periphery of the wafer by a small centrifugal force, eliminating chuck marks.

[0010] The invention described in claim 2 provides a wafer holding device in which, in the configuration described in claim 1, each of the claw portions is provided with a drainage passage having a drainage port.

[0011] With this configuration, when the holding device is rotated at high speed with the wafer after cleaning, the water accumulated at each point where the claws grip the wafer is moved towards the claws by centrifugal force and is sucked into the drainage passage from the drain port and drained away.

[0012] The invention described in claim 3 is the configuration described in claim 2, wherein the drainage passage is a slit-shaped gap formed between the first to third restricting portions. We provide a wafer holding device.

[0013] With this configuration, the slit-shaped gaps formed between the first to third restricting portions, which are offset in the circumferential direction of the wafer, can be used as drainage passages to discharge water accumulated at each point where the wafer is gripped.

[0014] The invention described in claim 4 provides a wafer holding device in which, in the configuration described in claim 2, the drainage passage is a drainage hole formed in any of the first to third restricting sections.

[0015] With this configuration, by forming the drainage passage in the shape of a hole, it is possible to create a drainage passage without reducing the strength of the claw portion. [Effects of the Invention]

[0016] According to the invention, the claw portion gripping the wafer is divided into at least two groups, and the area of ​​contact between each restricting portion of the claw portion and the wafer is reduced. As a result, the amount of water that accumulates at each contact point is reduced, and the surface tension of the water at each point is reduced. Consequently, when the wafer is rotated with the claw portion during drying, the water accumulated at each point gripping the wafer by the claw portion is easily ejected from the periphery of the wafer by a small centrifugal force, thus reducing chuck marks at the points gripping the wafer by the claw portion during drying after washing. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view showing the entire wafer support device according to one embodiment of the present invention. [Figure 2] This is a perspective view showing the claw portion of the wafer support device as seen from the front. [Figure 3] The diagram illustrates the operation of the claw portion, where (a) is a view of the claw portion from the side, (b) is a view of the claw portion from the back, (c) is a view of the claw portion from the top, and (d) is a cross-sectional view of (a) along line AA. [Modes for carrying out the invention]

[0018] The present invention aims to provide a wafer holding device that can eliminate water remaining at the locations where the wafer is gripped by claw portions during drying after washing and reduce chuck marks. To achieve this purpose, the wafer holding device grips and rotates the peripheral edge of the wafer with a plurality of claw portions, and performs water washing and drying of the wafer. Each of the claw portions includes a first restricting portion that restricts the horizontal movement of the wafer, a second restricting portion that restricts the upward movement of the wafer, and a third restricting portion that restricts the downward movement of the wafer. At least one of the first to third restricting portions is arranged by being shifted in the circumferential direction of the wafer, which is realized by such a configuration.

Embodiment

[0019] Hereinafter, an example according to an embodiment of the present invention will be described in detail based on the accompanying drawings. In the following examples, when referring to the number, numerical value, amount, range, etc. of components, unless specifically stated or limited to a specific number in principle, it is not limited to that specific number, and it may be more or less than the specific number.

[0020] Also, when referring to the shape, positional relationship, etc. of components, unless specifically stated or considered not to be so in principle, it includes those substantially approximating or similar to the shape, etc.

[0021] Also, the drawings may be exaggerated, such as enlarging characteristic parts for easy understanding of the characteristics, and the dimensional ratios of components are not necessarily the same as the actual ones. In sectional views, in order to make the sectional structure of components easy to understand, the hatching of some components may be omitted.

[0022] Also, in the following description, expressions indicating directions such as up and down, left and right, etc. are not absolute. They are appropriate when the parts of the wafer holding device of the present invention are depicted in a certain posture. However, when the posture changes, they should be interpreted according to the change in posture. Also, the same reference numerals are assigned to the same elements throughout the description of the embodiment.

[0023] Figure 1 is a perspective view showing the entire wafer support device 10 according to the present invention. The wafer support device 10 shown in Figure 1 includes a rotating arm body 11 for placing and gripping a wafer W to be cleaned. A motor 12 is fixed to the center of the lower surface of the rotating arm body 11 for rotating the rotating arm body 11 together with the wafer W. The motor 12 is provided with an output shaft 12a, and the entire rotating arm body 11 is rotatably supported by this output shaft 12a. The operation of the wafer support device 10 is controlled by control means (not shown). The control means controls each component that constitutes the wafer support device 10, and is, for example, a computer, which consists of a CPU, memory, etc. The function of the control means may be realized by control using software, or it may be realized by operating using hardware.

[0024] The rotating arm body 11 is provided with three arms 13 that extend horizontally and radially outward from the center. A pair of claw portions 14 are provided on both sides in the direction of rotation, flanking each arm 13 at the tip of each arm 13.

[0025] Each arm 13 has a pair of claws 14, which are positioned at the tip of each arm 13, approximately perpendicular to the arm 13, and are attached to each arm 13 via an operating member 15, forming a T-shape together with the arm 13. Each operating member 15 is moved left and right by the operation of a claw opening / closing mechanism 16 attached to each arm 13, and this movement switches the position of the claws 14 relative to the wafer W, allowing it to switch between a chuck position, where the claws 14 are in approximate contact with the periphery of the wafer W, and a release position, where the claws 14 are separated from the periphery of the wafer W and detached from the wafer W. In other words, the operating member 15 switches the position of the claws 14 between the chuck position and the release position in response to the operation of the claw opening / closing mechanism 16. The operation of the claw opening / closing mechanism 16 is controlled by the control means described above.

[0026] The claw portion 14 is shown in detail in Figures 2 and 3. Figure 2 is a perspective view of the claw portion 14 of the wafer support device 10 as seen from the front side (the side on which the wafer W is placed). Figure 3 is a diagram illustrating the operation of the claw portion 14, where (a) is a view of the claw portion 14 from the side, (b) is a view of the claw portion 14 from the back side, (c) is a view of the claw portion 14 from the top side, and (d) is a cross-sectional view of (a) along line AA.

[0027] In Figures 2 and 3, the claw portion 14 comprises a claw portion body 14a connected to the operating member 15, a first restricting portion 14A provided at the upper end of the claw portion body 14a for restricting the horizontal movement of the wafer W, a second restricting portion 14B for restricting the vertical upward movement of the wafer W, and a third restricting portion 14C for restricting the vertical downward movement of the wafer W. Furthermore, the claw portion 14 is divided into two main groups, with the first restricting portion 14A and the second restricting portion 14B forming the first group 21, and the third restricting portion 14C forming the second group 22.

[0028] The first restricting portion 14A of the first group 21 is a block body extending upward from the upper end of the claw body 14a, and one side surface 14Aa of the first restricting portion 14A is formed as a side surface that substantially follows a line passing through the rotation center of the rotating arm body 11 (center of the output shaft 12a). The other side surface 14Ab of the first restricting portion 14A, which is opposite to the one side surface 14Aa, is formed as a side surface that is inclined to tilt toward the one side surface 14Aa, and the side surfaces 14Aa and 14Ab form a substantially acute angle in the horizontal cross-section. Furthermore, when the wafer W is placed on the wafer support device 10, the ridge portion of the first restricting portion 14A corresponding to the outer circumferential surface of the wafer W is chamfered and formed into a planar shape as the wafer contact surface 14Ac. Furthermore, the side surface 14Ab of the first restricting section 14A is provided with two drainage passages 18 arranged vertically, each having a drainage port 18a facing the rotation center of the wafer W. Each drainage passage 18 opens to the back surface of the first restricting section 14A. In this embodiment, the inner diameter of the drainage passage 18 is approximately 2 mm.

[0029] Similarly, the second restricting portion 14B of the first group 21 is bent at approximately a right angle inward (towards the side where the wafer W is placed) from a position slightly above the first restricting portion 14A, and this bent tip portion 14Ba is positioned to protrude inward from the wafer contact surface 14Ac of the first restricting portion 14A. That is, when the claw portion 14 is positioned in the chuck position and the outer peripheral surface of the wafer W is in contact with the wafer contact surface 14Ac of the first restricting portion 14A, the bent tip portion 14Ba of the second restricting portion 14B protrudes significantly to a position that overlaps with the upper surface of the wafer W, and is set to restrict the upward movement of the wafer W.

[0030] On the other hand, the third restricting portion 14C, which forms the second group 22, is a block body that extends further upward from the upper end of the claw portion body 14a, similar to the first restricting portion 14A of the first group 21. Furthermore, the position of the third restricting portion 14C, which forms the second group 22, is shifted in the circumferential direction of the wafer W relative to the positions where the first restricting portion 14A and the second restricting portion 14B, which form the first group 21, are located. Furthermore, by positioning the third restricting portion 14C, which forms the second group 22, circumferentially on the wafer W relative to the first restricting portion 14A and the second restricting portion 14B, which form the first group 21, the gap between the side surface 14Aa of the first restricting portion 14A and the side surface 14Ca of the third restricting portion 14C forms a slit-shaped drainage passage 17 that penetrates to the back side and has a drainage port 17a facing the line passing through the rotation center of the rotating arm body 11 (center of the output shaft 12a), i.e., a drainage port 17a facing the rotation center. In this embodiment, the width of the gap between the side surface 14Aa of the first restricting portion 14A and the side surface 14Ca of the third restricting portion 14C, i.e., the width of the drainage passage 17, is set to approximately 1 mm.

[0031] Furthermore, the other side surface 14Cb of the third restricting portion 14C is formed as a side surface that is inclined toward the other side surface 14Ca. The side surfaces 14Ca and 14Cb form a roughly acute angle in the horizontal cross-section, and the ridge portion 14Cc is formed as an acute-angled edge. In addition, when the wafer W is set in a predetermined position on the wafer support device 10, the ridge portion 14Cc intersects the circumferential surface of the wafer W at roughly a right angle and is inclined downward from the outside to the inside of the outer circumference of the wafer W. In this way, by forming the ridge portion 14Cc of the third restricting portion 14C as an acute-angled edge and inclining it downward from the outside to the inside relative to the wafer W, the wafer W placed in a predetermined position on the wafer support device 10 is set with the edge portion of the lower circumferential surface of the wafer W in point contact with the ridge portion 14Cc of the third restricting portion 14C.

[0032] Next, the operation of the wafer support device 10 will be described. Before the wafer W is transported onto the rotating arm body 11, each claw portion 14 attached to each operating member 15 is positioned in the release position. That is, upon receiving instructions from the control means, the claw portion opening / closing mechanism 16 is operated, and the operation of the claw portion opening / closing mechanism 16 is then transmitted to each operating member 15, causing each operating member 15 to move the claw portion 14 away from the periphery of the wafer W and position it in the release position so as not to interfere with the transport of the wafer W.

[0033] Then, when the wafer W, which has been transported by a wafer transport device (not shown), is placed in a predetermined position on the wafer support device 10, the claw opening / closing mechanism 16 is operated by an instruction from the control means, and the operation of this claw opening / closing mechanism 16 is transmitted to each operating member 15, so that each claw portion 14 is positioned in the chuck position. Then, multiple (six in this embodiment) claw portions 14 are arranged to surround the wafer W and grip the wafer W onto the rotating arm body 11.

[0034] In this way, the wafer W gripped on the rotating arm body 11 by each claw portion 14 is held (held) in such a state as shown in Figures 2 and 3, with the lower peripheral edge of the wafer W resting in point contact with the ridge portion 14Cc of the third restricting portion 14C, the outer peripheral surface of the wafer W adjacent to the wafer contact surface 14Ac of the first restricting portion 14A, and the upper peripheral portion of the wafer W positioned below the bent tip portion 14Ba of the second restricting portion 14B.

[0035] In this way, the wafer W, which is gripped by each claw portion 14 on the rotating arm body 11, is positioned such that its downward positioning is restricted by the third restricting portion 14C because the peripheral edge on the lower side of the wafer W rests in point contact with the ridge portion 14Cc of the third restricting portion 14C; its horizontal positioning is restricted by the first restricting portion 14A because the outer peripheral surface of the wafer W comes into contact with the wafer contact surface 14Ac of the first restricting portion 14A; and its upward movement is restricted by the second restricting portion 14B because the upper surface of the wafer W collides with the lower surface of the bent tip portion 14Ba of the second restricting portion 14B.

[0036] Therefore, even when the rotating arm 11 grips the wafer W and rotates at high speed, the wafer W, which is gripped by the claw portion 14, will not fly out of the rotating arm 11.

[0037] In this way, when spin cleaning is performed, the wafer W held on the rotating arm 11 is rotated together with the rotating arm 11, and cleaning water is sprayed onto the surface of the wafer W from a nozzle (not shown) to wash it off, thereby enabling spin cleaning.

[0038] Furthermore, once cleaning is complete, the spraying of cleaning water from the nozzle is stopped, and the rotating arm 11 on which the wafer W is set is continued to rotate at high speed. The cleaning water remaining on the surface of the wafer W is moved to the outer circumference by centrifugal force and falls off the wafer W, removing it. In addition, drying can be performed by blowing drying air onto the wafer W. The cleaning water accumulated between the claw portion 14 and the wafer W is discharged from the back side of the claw portion 14 through a drainage passage 17, which is formed to follow the line passing through the rotation center of the rotating arm 11 (the center of the output shaft 12a) and is a gap provided between the side surface 14Aa of the first restricting portion 14A and the side surface 14Ca of the third restricting portion 14C, and a drainage passage 18, which is a circular hole provided in the side surface 14Ab of the first restricting portion 14A. This completes the drying process of the wafer W on the rotating arm 11.

[0039] Once the drying process of the wafer W is complete, the claw opening / closing mechanism 16 is operated by an instruction from the control means, and the operation of this claw opening / closing mechanism 16 is transmitted to each operating member 15, causing each claw portion 14 to be positioned in the release position. Then, the multiple (six in this embodiment) claw portions 14 separate from the wafer W, releasing their restraint (gripping) on ​​the wafer W. The wafer W, which is placed on the rotating arm body 11, is then moved to the next process by a wafer transport device (not shown).

[0040] Therefore, according to the wafer support device 10 of this embodiment, the claw portion 14 is formed by a first restricting portion 14A that restricts the horizontal movement of the wafer W, a second restricting portion 14B that restricts the upward movement of the wafer W, and a third restricting portion 14C that restricts the downward movement of the wafer W. Furthermore, the three restricting portions, the first restricting portion 14A, the second restricting portion 14B, and the third restricting portion 14C, are divided into at least two groups, a first group 21 and a second group 22. Each restricting portion 14A, 14B, and 14C is positioned offset in the circumferential direction of the wafer W for each group 21 and 22. As a result, the area of ​​contact between each restricting portion 14A, 14B, and 14C of the claw portion 14 that grips the wafer W and the wafer is divided and reduced. This reduces the amount of water that accumulates at each contact point, and the surface tension of the water at each contact point is reduced. As a result, when the wafer W is rotated during drying, the water accumulated at each point where the claw portion 14 grips the wafer W is easily ejected from the periphery of the wafer W by a small centrifugal force, thereby reducing chuck marks at the points where the claw portion 14 grips the wafer W during drying after washing.

[0041] Furthermore, the positions of the first group 21 and the second group 22 are shifted in the circumferential direction of the wafer W, and the slit-shaped gap formed between the first group 21 and the second group 22 is used as a drainage passage 17 having a drainage port 17a that is substantially opposite to the line passing through the rotation center of the wafer W. This allows water accumulated at each point where the wafer W is gripped to be sucked into the drainage passage 17 from the drainage port 17a and then conveniently drained through the drainage passage 17. This further reduces the amount of water that accumulates at each point where the claw portion 14 grips the wafer W.

[0042] Furthermore, since the side surface 14Ab of the first restricting portion 14A is provided with two drainage passages 18 arranged vertically, each having a drainage port 18a facing the rotational center of the wafer W, water accumulating at each point where the wafer W is gripped can be drawn into the drainage passages 18 from the drainage port 18a and then conveniently drained through the drainage passages 18. This further reduces the amount of water accumulating at each point where the claw portion 14 grips the wafer W.

[0043] Furthermore, although the second regulating section 14B is disclosed as being located on top of the first regulating section 14A, it can also be located on top of the third regulating section 14C. Additionally, the first regulating section 14A can be configured as the first group 21, and the second regulating section 14B and the third regulating section 14C can be configured as the second group 22.

[0044] Furthermore, the first restricting portion 14A, the second restricting portion 14B, and the third restricting portion 14C can be formed independently, and the first restricting portion 14A, the second restricting portion 14B, and the third restricting portion 14C can be arranged offset from each other in the circumferential direction of the wafer W, and the gaps formed between the first restricting portion 14A, the second restricting portion 14B, and the third restricting portion 14C can be used as drainage passages 17. [Industrial applicability]

[0045] Furthermore, the present invention can be modified in various ways as long as it does not depart from the spirit of the invention, and it goes without saying that the present invention extends to such modified forms. [Explanation of symbols]

[0046] 10: Wafer support device 11: Rotating Arm Body 12: Motor 12a: Output shaft 13: Arm 14: Nail area 14A: First regulatory section 14Aa: Side view 14Ab: Side view 14Ac: Wafer contact surface 14B: Second regulatory section 14Ba: Folded tip 14C: Third Regulatory Section 14Ca: Side 14Cb: Side 14Cc: Partial 14a: Claw body 15: Operating member 16: Claw opening and closing mechanism 17: Drainage passage (gap) 17a: Drain port 18: Drain passage (drain hole) 18a: Drain port 21: First group 22: Second group W: wafer

Claims

1. A wafer holding device that rotates while gripping a peripheral edge of a wafer with a plurality of claws, and performs water cleaning and drying of the wafer, each of the claws includes a first restricting portion that restricts horizontal movement of the wafer, a second restricting portion that restricts upward movement of the wafer, and a third restricting portion that restricts downward movement of the wafer; At least one of the first to third restricting portions is disposed so as to be shifted in the circumferential direction of the wafer. A wafer holding device characterized by:

2. 2. The wafer holding device according to claim 1, wherein each of said claws includes a drain passage having a drain outlet.

3. 3. The wafer holding device according to claim 2, wherein the drain passage is a slit-shaped gap formed between the first to third restricting portions.

4. 3. The wafer holding device according to claim 2, wherein the drain passage is a drain hole formed in one of the first to third restricting portions.

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