Wafer holder

Abstract

A wafer holder A1 holds a plurality of wafers in a state of being aligned in a first direction x such that the surfaces thereof face each other. The wafer holder A1 comprises two groove arrays 4 which each include a plurality of holding grooves 40 aligned in the first direction x and which are apart from each other in a second direction y orthogonal to the first direction x. In each of the holding grooves 40, one side in a third direction z orthogonal to the first direction x and the second direction y is open, the other side in the third direction z is at least partially closed, and a wide width part 401 and a narrow width part 402 are provided. The narrow width part 402 is positioned more inward in the second direction y as compared to the wide width part 401, and also on the other side in the third direction z. The width X2 of the narrow width part 402 in the first direction x at the end portion on the other side in the third direction z is smaller than the width X1 of the wide width part 401 in the first direction at the end portion on the other side in the third direction z. By such a configuration, a plurality of wafers can be more suitably aligned and held.

Description

Wafer holder

[0001] The present invention relates to a wafer holder.

[0002] For example, wafers of semiconductor material created by slicing a single crystal ingot of semiconductor material are used as the material for various semiconductor products. In the manufacturing process of semiconductor products, a wafer holder is used to hold multiple wafers in an aligned state. Patent Document 1 discloses an example of a conventional wafer holder. The wafer holder disclosed in this document has two rows of grooves. The two rows of grooves are arranged facing each other with a distance between them. Each groove row includes multiple holding grooves. One wafer is held by the two opposing holding grooves. This allows the wafer holder to hold multiple wafers in an aligned state.

[0003] Japanese Patent Application Publication No. 2-78246

[0004] The width of the holding groove is preferably set to a size equal to the wafer thickness plus a margin. The larger the margin, the easier it is to insert the wafer into the holding groove. However, a large margin makes the wafer held in the holding groove more likely to tilt. If the wafer tilts, adjacent wafers may come into contact with each other. For example, in a process in which multiple wafers are immersed in a processing liquid or washed with a cleaning liquid, the contact areas between the wafers may not be processed properly. The thinner the wafer, the more difficult it is to set an appropriate margin.

[0005] The present invention was conceived in light of the above circumstances, and an object of the present invention is to provide a wafer holder that can more appropriately align and hold a plurality of wafers.

[0006] The wafer holder provided by the present invention is a wafer holder that holds multiple wafers aligned in a first direction with their surfaces facing each other, and has two groove rows that each include a multiple number of holding grooves arranged in the first direction and are spaced apart in a second direction perpendicular to the first direction, and each of the holding grooves is open on one side in a third direction perpendicular to the first and second directions and is closed at least partially on the other side in the third direction, and has a wide portion and a narrow portion, and the narrow portion is located inside the wide portion in the second direction and on the other side in the third direction, and the width in the first direction at the end on the other side in the third direction of the narrow portion is smaller than the width in the first direction of the wide portion at the end on the other side in the third direction of the narrow portion.

[0007] In a preferred embodiment of the present invention, the device further comprises two legs, each of which is located on the other side of the two groove rows in the third direction, and the retaining groove has a bottom at its inner end in the second direction that blocks the other side in the third direction, and the legs have a discharge portion that is connected to the bottom and extends to the second side in the third direction.

[0008] In a preferred embodiment of the present invention, the width of the narrow portion decreases from the outside toward the inside in the second direction.

[0009] In a preferred embodiment of the present invention, the narrow portion includes the bottom portion.

[0010] In a preferred embodiment of the present invention, the inner surface includes a convex curved surface portion connected to the bottom portion, and a flat surface portion connected to the other side of the curved surface portion in the third direction.

[0011] According to the present invention, a plurality of wafers can be more appropriately aligned and held.

[0012] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0013] 9 is a perspective view showing a wafer holder according to a first embodiment of the present invention. FIG. 10 is a plan view showing a wafer holder according to a first embodiment of the present invention. FIG. 11 is a front view showing a wafer holder according to a first embodiment of the present invention. FIG. 12 is a side view showing a wafer holder according to a first embodiment of the present invention. FIG. 13 is a cross-sectional view showing a wafer holder according to a first embodiment of the present invention. FIG. 14 is a cross-sectional view showing a wafer holder according to a first embodiment of the present invention. FIG. 15 is a partially enlarged cross-sectional perspective view showing a wafer holder according to a first embodiment of the present invention. FIG. 16 is a partially enlarged cross-sectional perspective view showing a wafer holder according to a first embodiment of the present invention. FIG. 17 is a partially enlarged cross-sectional view showing a wafer holder according to a first embodiment of the present invention. FIG. 18 is a partially enlarged cross-sectional view showing a wafer holder according to a first modification of the first embodiment of the present invention. FIG. 19 is a partially enlarged cross-sectional view showing a wafer holder according to a second modification of the first embodiment of the present invention. FIG. 19 is a partially enlarged plan view showing a wafer holder according to a third modification of the first embodiment of the present invention. FIG. 19 is a partially enlarged cross-sectional perspective view showing a wafer holder according to a fourth modification of the first embodiment of the present invention.

[0014] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0015] The terms "first," "second," "third," etc. in this disclosure are used for identification purposes only and are not intended to impose any ranking on their objects.

[0016] 1 to 13 show a wafer holder according to a first embodiment of the present invention. Wafer holder A1 of this embodiment includes a main body 1, two rib rows 2, two leg portions 3, two groove rows 4, and an opening 5. FIG. 5 is a cross-sectional view in the yz plane intersecting with a rib 20, which will be described later. FIG. 6 is a cross-sectional view in the yz plane intersecting with a holding groove 40, which will be described later. FIG. 7 includes a cross-section in the yz plane intersecting with a rib 20, which will be described later. FIG. 8 includes a cross-section in the yz plane intersecting with a holding groove 40, which will be described later.

[0017] In these figures, the first direction x is the direction in which multiple wafers W are aligned. The third direction z is a direction that can be vertical when the wafer holder A1 is in use, and one side of the third direction z may be referred to as the "upper side" and the other as the "lower side." In the second direction y, the side toward the center of the wafer holder A1 may be referred to as the "inner side," and the side away from the center may be referred to as the "outer side."

[0018] The specific configuration of the multiple wafers W held by the wafer holder A1 is not limited in any way. The material of the wafers W is, for example, a semiconductor material such as Si or SiC. The wafers W may, for example, be circular overall, and may have a flat portion (orientation flat), a notch, or the like. The diameter of the wafers W is not limited in any way and is, for example, about 50 mm to 300 mm. The thickness t of the wafers W is not limited in any way and is, for example, about 300 μm to 800 μm.

[0019] The material of the wafer holder A1 is not limited in any way and may be, for example, fluororesin, engineering plastic, general-purpose resin, ceramics, quartz glass, etc. Examples of fluororesin include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer). Examples of engineering plastic include PEEK (polyether ether ketone), PEI (polyetherimide), PC (polycarbonate), and PBT (polybutylene terephthalate). Examples of general-purpose resin include PP (polypropylene). The wafer holder A1 may be integrally formed, for example, by mold molding, or may be formed as a combination of multiple parts.

[0020] The main body 1 forms the main structure of the wafer holder A1. There are no particular limitations on the specific configuration of the main body 1, and in this embodiment, as shown in Figures 1 to 6, the main body 1 has two side portions 11 and two end portions 12.

[0021] The two side portions 11 each have a shape that is generally along the first direction x and are spaced apart from each other in the second direction y. The specific configuration of the side portion 11 is not limited in any way, and in this embodiment, the side portion 11 has an upper end portion 111 and multiple frame portions 112, 113, and 114.

[0022] The upper end 111 constitutes the upper end of the side portion 11 in the third direction z and has a shape extending in the first direction x. The upper end 111 may have a shape that further protrudes outward in the second direction y. The multiple frame portions 112, 113, and 114 each have a shape extending in the first direction x and are arranged in this order from above to below in the third direction z, spaced apart from each other. As shown in FIG. 6 , in the illustrated example, the frame portion 112 is located directly below the upper end 111 in the third direction z. The upper end 111, the frame portions 112, and the frame portions 113 are positioned along the outer shape of the wafer W to be held.

[0023] The two end portions 12 are spaced apart from each other in the first direction x, and are connected to the ends of the two side portions 11 in the first direction x. The specific configuration of the end portions 12 is not limited in any way. In the example shown, one end portion 12 has a wall shape without an opening. The other end portion 12 has a shape with an opening. The specific shape of the end portions 12 can be set appropriately depending on, for example, the engagement relationship with a transport means when transporting the wafer holder A1, or the requirements of the processing performed while holding multiple wafers W, etc.

[0024] In this embodiment, the two rib rows 2 are provided to define the two groove rows 4. The two rib rows 2 are spaced apart from each other in the second direction y. Each of the two rib rows 2 includes a plurality of ribs 20 arranged in the first direction x. The plurality of ribs 20 are connected to the side portion 11.

[0025] The specific shape of the rib 20 is not limited in any way, and in the illustrated example, the rib 20 has an arc portion 21 and a straight portion 22 as shown in Fig. 5. The arc portion 21 is located below in the third direction z, is connected to the frame portions 112, 113, and 114, and has an arc shape that follows the frame portions 112, 113, and 114. The straight portion 22 is located above in the third direction z, and is connected to the upper end portion 111 and the frame portion 112.

[0026] The ribs 20 of the two rib rows 2 face each other in the second direction y, but are positioned approximately the same in the first direction x. In the example shown in Figures 10 and 11, the upper ends of the ribs 20 in the third direction z may have a curved shape. The thickness of the ribs 20 in the first direction x is not limited, and is, for example, about 1.5 mm to 4 mm. The height of the ribs 20 in the third direction z is also not limited, and is, for example, about 5 mm to 12 mm.

[0027] The two legs 3 are connected to the two side portions 11 below in the third direction z. In other words, the two legs 3 are located below the two groove arrays 4 described below in the third direction z. The two legs 3 are used, for example, when placing the wafer holder A1 on a flat surface. The legs 3 have an inner surface 31. The inner surface 31 is a surface located inside in the second direction y.

[0028] The opening 5 is provided between the two end portions 12 in the first direction x and between the two leg portions 3 (inner surfaces 31) in the second direction y. The opening 5 is a portion that is open on both sides in the third direction z.

[0029] The two groove arrays 4 are for holding a plurality of wafers W aligned in the first direction x. The two groove arrays 4 are spaced apart from each other in the second direction y. Each of the two groove arrays 4 includes a plurality of holding grooves 40. As will be described below, in this embodiment, the two groove arrays 4 are formed by two side portions 11 and two rib arrays 2, but the specific configuration for forming the two groove arrays 4 is not limited in any way. For example, the plurality of holding grooves 40 may be carved into a solid member by melt-molding using a mold.

[0030] The plurality of holding grooves 40 are arranged in the first direction x. The plurality of holding grooves 40 in the two groove rows 4 face each other in the second direction y, but are positioned approximately in the same position in the first direction x. The specific configuration of the holding grooves 40 is not limited in any way, and in this embodiment, as shown in Figures 6 and 8 to 12, the holding grooves 40 have a plurality of bottoms 411, 412, 413, 414 and two inner side surfaces 42.

[0031] The plurality of bottom portions 411, 412, 413, and 414 are portions that restrict movement of the wafer W in the third direction z or the second direction y. Gaps are provided between the plurality of bottom portions 411, 412, 413, and 414. For ease of understanding, the bottom portion 413 and the bottom portion 414 are hatched with a plurality of discrete dots in FIGS. 9, 11, and 12.

[0032] The two inner surfaces 42 face each other in the first direction x. In the present embodiment, the inner surface 42 is formed by one surface of the rib 20. In the illustrated example, as shown in Figures 10 and 11 , the distance between the two inner surfaces 42 in the first direction x decreases from above to below in the third direction z.

[0033] 8 , 9 , 11 , and 12 , the holding groove 40 has a wide portion 401 and a narrow portion 402. The wide portion 401 is located more inward in the second direction y than the narrow portion 402 and lower in the third direction z. In the illustrated example, the narrow portion 402 is located at the inner end of the holding groove 40 in the second direction y and at the lower end in the third direction z. However, the narrow portion 402 may be located at the inner end of the holding groove 40 in the second direction y and away from the lower end in the third direction z in both the second direction y and the third direction z.

[0034] In the illustrated example, the wide width portion 401 is a portion of the holding groove 40 that extends from the bottom 411, via the bottoms 412 and 413, to the outer end of the bottom 414 in the second direction y. In the illustrated example, the narrow width portion 402 is a portion of the holding groove 40 that is formed by the bottom 414. Note that there are no limitations on the sizes or positions of the wide width portion 401 and the narrow width portion 402 in the holding groove 40. For example, a configuration in which a plurality of wide width portions 401 and a plurality of narrow width portions 402 are arranged alternately may be used.

[0035] In the illustrated example, the width of the wide portion 401 in the first direction x is constant and is designated as width X1. The width of the narrow portion 402 in the first direction x is smaller than the width (width X1) of the wide portion 401 in the first direction x. The width of the narrow portion 402 in the first direction x at the lower end (inner end in the second direction y) of the narrow portion 402 in the third direction z is designated as width X2. Width X2 is smaller than width X1. When the thickness t of the wafer W is approximately 300 μm to 500 μm, width X1 is, for example, approximately 0.5 mm to 1.5 mm, and width X2 is, for example, approximately 0.3 mm to 1.0 mm. Width X2 may be 1 to 3 times the thickness t. Furthermore, in order to prevent contact between adjacent wafers W, width X2 is preferably 2.5 times or less, more preferably 2 times or less, of thickness t. In order to prevent the wafer W from getting caught, width X2 is preferably greater than 1 time the thickness t.

[0036] In the illustrated example, the narrow width portion 402 has a tapered portion 4021 and a constant width portion 4022. The tapered portion 4021 is located below the wide width portion 401 in the third direction z and connected to the inside in the second direction y. The width of the tapered portion 4021 in the first direction x decreases from the outside to the inside in the second direction y (from above to below in the third direction z). The constant width portion 4022 is located below the tapered portion 4021 in the third direction z and connected to the inside in the second direction y. The width of the constant width portion 4022 in the first direction x is constant. Note that the specific configuration of the narrow width portion 402 is not limited in any way, and for example, the narrow width portion 402 may be entirely composed of only either the tapered portion 4021 or the constant width portion 4022.

[0037] As shown in Figures 7, 8, 12, and 13, the leg 3 has a discharge portion 32. The discharge portion 32 is connected to the bottoms 414 of the multiple holding grooves 40 and extends downward in the third direction z. The specific configuration of the discharge portion 32 is not limited in any way. It can be configured in various ways, such as multiple grooves connected to the bottoms 414 of the multiple holding grooves 40, multiple holes, or a surface smoothly connected to the bottoms 414. In the illustrated example, multiple discharge portions 32 each configured as a groove are used. Each of these discharge portions 32 is recessed outward in the second direction y from the inner surface 31. The size of the discharge portion 32 is not limited in any way, and the size in the third direction z is, for example, approximately 0.1 mm to 10 mm, and the depth in the second direction y is, for example, approximately 0.1 mm to 1.0 mm.

[0038] As shown in FIG. 7 , in the illustrated example, the inner surface 31 has a curved surface portion 311 and a flat surface portion 312. The curved surface portion 311 is located above the third direction z and connected to the bottom portion 414. The curved surface portion 311 is a convex curved surface that bulges upward in the third direction z and inward in the second direction y. The flat surface portion 312 is connected below the curved surface portion 311 in the third direction z and is a flat surface that extends along the first direction x and the third direction z. That is, in the illustrated example, the inner surface 31 has a shape that protrudes further inward in the second direction y from the inner end of the holding groove 40 (bottom portion 414) in the second direction y. The discharge portion 32 is recessed from the entire curved surface portion 311 and a portion of the flat surface portion 312. Note that the discharge portion 32 formed by a groove may have a wide width such that one discharge portion 32 includes multiple holding grooves 40. Alternatively, unlike this example, the inner surface 31 having the curved surface portion 311 smoothly connected to the bottom portion 414 may function as the discharge portion 32 without forming any grooves or the like.

[0039] Next, the operation of the wafer holder A1 will be described.

[0040] According to this embodiment, as shown in FIGS. 8 , 9 , 11 , and 12 , the holding groove 40 has a wide portion 401 and a narrow portion 402. As illustrated in FIG. 1 , when multiple wafers W are inserted into the wafer holder A1 from above in the third direction z, the wafers W are inserted into the wide portion 401 of the holding groove 40. The wide portion 401 has a relatively wide width in the first direction x, e.g., width X1. This allows the wafers W to be inserted more smoothly into the holding groove 40. When the wafers W are further inserted downward in the third direction z, they reach the narrow portion 402. The narrow portion 402 has a relatively narrow width in the first direction x, e.g., width X2. As a result, when the wafers W reach the narrow portion 402, they are raised to a position aligned with the third direction z. This allows the upper ends of the multiple wafers W in the third direction z to be arranged at a more equal pitch. This allows the multiple wafers W to be more appropriately aligned. This makes it easier to maintain an appropriate gap between adjacent wafers and prevents contact between the wafers, which has the advantage of reducing the risk of insufficient processing, for example, in processes in which multiple wafers are immersed in a processing solution or washed with a cleaning solution.

[0041] Furthermore, if liquid adheres to the wafers W during processing of the wafers W, the liquid will drip down along the wafers W in the third direction z. The holding groove 40 has a narrow width portion 402 below the third direction z, which narrows the gap between the wafers W and the inner surface 42. The narrower this gap, the more likely liquid will remain. Residual liquid may cause unintended deterioration in the quality of the wafers W or contaminate the wafers W being held for subsequent processing. In this embodiment, the leg 3 is provided with multiple discharge portions 32. This allows liquid that has dripped down the narrow width portion 402 to be discharged to the opening 5 via the discharge portions 32. This reduces problems caused by residual liquid.

[0042] Proper alignment of multiple wafers W and enhanced liquid drainage become particularly important as the thickness t of the wafers W decreases. The wafer holder A1 allows multiple wafers W with a thin thickness t to be aligned and held at a smaller pitch. This is therefore preferable for improving processing efficiency when multiple wafers W are processed simultaneously while held by the wafer holder A1. In particular, in recent years, a method has begun to be adopted in which the wafer pitch in a wafer holder is set to, for example, about half the conventional pitch, thereby holding twice the number of wafers per wafer holder, thereby more efficiently processing multiple wafers. In such cases, there is a trend toward using thinner wafers. Given this industry trend, this embodiment allows for more efficient wafer processing.

[0043] The narrow width portion 402 has the tapered portion 4021 , which can prevent the wafer W from getting caught when the wafer W is inserted into the holding groove 40 .

[0044] Since the narrow width portion 402 is configured to include the bottom portion 414, the liquid that has dripped down the wafer W can be received by the bottom portion 414 and can be quickly guided to the discharge portion 32. This improves the efficiency of discharging the liquid.

[0045] The inner surface 31 has a curved portion 311 and a flat portion 312. This gives the inner surface 31 a shape that protrudes inward in the second direction y from the bottom portion 414. Therefore, although the ejection portion 32 is recessed outward in the second direction y from the inner surface 31, it is not essential that it bites into the holding groove 40 (bottom portion 414). Therefore, for example, it is possible to give the ejection portion 32 a shape and size suitable for ejection while avoiding the shape of the holding groove 40 from being distorted.

[0046] 14 to 17 show modified examples of the present invention. In these figures, elements that are the same as or similar to those in the above-described example are given the same reference numerals. Furthermore, the configurations of the various parts in each modified example and each embodiment can be combined with each other as appropriate within the scope of not causing technical contradictions.

[0047] 14 to 16 show modified examples of the wafer holder A1. In these modified examples, the configuration of the narrow portion 402 differs from the example described above.

[0048] 14 , narrow width portion 402 includes only tapered portion 4021. That is, throughout narrow width portion 402, the width in first direction x decreases from the outside toward the inside in second direction y.

[0049] 15, narrow width portion 402 includes only constant width portion 4022. That is, the width of narrow width portion 402 in the first direction x is constant throughout the entire narrow width portion 402.

[0050] 16 , narrow width portion 402 includes a tapered portion 4021 and a reverse tapered portion 4023. Reverse tapered portion 4023 is connected to the inside of constant width portion 4022 in the second direction y. The width of reverse tapered portion 4023 in the first direction x increases from the outside toward the inside in the second direction y.

[0051] As can be seen from wafer holders A11, A12, and A13, there are no limitations on the specific configuration of narrow width portion 402. As can be seen from wafer holder A13, there is no limitation on the configuration in which the width in first direction x of narrow width portion 402 at the inner end in second direction y is the smallest.

[0052] 17 shows wafer holder A14 according to a fourth modification of wafer holder A1. In this modification, inner surface 31 includes only flat surface portion 312 and does not include curved surface portion 311. Inner surface 31 can be generally flush with the inner end face of rib 20 in second direction y. In this modification, discharge portion 32 formed by a groove can be configured to bite into bottom portion 414 of holding groove 40 as viewed in third direction z.

[0053] As can be understood from this modification, there is no limitation on the specific configuration of the inner surface 31. When the plurality of discharge portions 32 are configured as grooves, they may be configured to be recessed from the inner surface 31 outward in the second direction y.

[0054] The wafer holder according to the present invention is not limited to the above-described embodiment, and the specific configuration of each part of the wafer holder according to the present invention can be freely modified in various ways.

[0055] A1, A11, A12, A13, A14: wafer holder 1: main body 2: rib row 3: leg 4: groove row 5: opening 11: side 12: end 20: rib 21: arc portion 22: straight portion 31: inner surface 32: discharge portion 40: holding groove 42: inner surface 111: upper end 112, 113, 114: frame 311: curved portion 312: flat portion 401: wide portion 402: narrow portion 411, 412, 413, 414: bottom 4021: tapered portion 4022: equal width portion 4023: reverse tapered portion W: wafer t: thickness x: first direction y: second direction z: third direction

Claims

1. A wafer holder that holds multiple wafers aligned in a first direction with their surfaces facing each other, and that has two groove rows each including a multiple number of holding grooves arranged in the first direction and spaced apart in a second direction perpendicular to the first direction, wherein the holding grooves are open on one side in a third direction perpendicular to the first and second directions and are at least partially closed on the other side in the third direction, and have a wide portion and a narrow portion, wherein the narrow portion is located inside the wide portion in the second direction and on the other side in the third direction, and the width in the first direction at the end of the narrow portion on the other side in the third direction is smaller than the width in the first direction of the wide portion at the end of the other side in the third direction.

2. The wafer holder of claim 1, further comprising two legs each positioned on the other side in the third direction with respect to the two groove rows, wherein the holding grooves have bottoms at their inner ends in the second direction that close off the other side in the third direction, and the legs have discharge portions that connect to the bottoms and extend to the second side in the third direction.

3. The wafer holder according to claim 2, wherein the width of the narrow portion decreases from the outside toward the inside in the second direction.

4. The wafer holder according to claim 3, wherein said narrow portion includes said bottom portion.

5. The wafer holder according to claim 4, wherein the inner surface includes a convex curved surface portion connected to the bottom portion, and a flat surface portion connected to the other side of the curved surface portion in the third direction.

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