JP4999597B2 - Single wafer type wafer case - Google Patents

Description

  The present invention relates to a wafer storage container (wafer case) that can store a thin semiconductor substrate, for example, a fragile semiconductor substrate such as a thinned silicon wafer or a compound semiconductor substrate without damage or breakage.

  In recent years, products incorporating semiconductor chips manufactured from silicon wafers or compound semiconductor wafers (hereinafter referred to as wafers), such as printed circuit boards and IC packages, have been reduced in size in response to lighter, thinner and smaller end products. It is becoming thinner and thinner. In order to realize such thin printed circuit boards and IC packages, the thickness of a semiconductor chip or the like incorporated therein, that is, a wafer having a very small thickness is required. For example, a final thickness of 20 μm to 200 μm is required for a 2 inch wafer, and a final thickness of 30 μm to 300 μm is required for a 4 inch to 10 inch wafer.

  However, such a thin wafer has a low strength, and there is a high possibility that the wafer is damaged or broken during processing or transport in a process of manufacturing a device (element) such as a semiconductor or a resistor. In particular, the wafer is thinned after the wafer back surface grinding process after the formation of semiconductor elements and the like. For example, a wafer container (wafer) in a wafer process, wafer transport or wafer transport up to an electrical property measurement process or a dicing process. A case with a special mechanism is used. For example, a wafer case is disclosed in which a central support portion for supporting the central portion of the wafer is provided in order to suppress bending of a thin wafer. (Patent Document 2006-332278) Such a thinned wafer becomes very fragile and requires careful handling.

Further, a single wafer type (contains one wafer) wafer case generally used conventionally is as shown in FIG. 7 (FIGS. 7A and 7B). FIG. 7A is a perspective view showing a state in which the upper case 74 is removed with the wafer stored, and FIG. 7B is a side sectional view of this state. This single wafer type wafer case can be separated into an upper case 74 and a lower case 71. The center portion of the bottom plate portion 75 of the lower case 71 is recessed downward in a conical shape, and the wafer 1 is placed in contact with the side surface of the outer peripheral portion of the conical bottom plate portion 75 of the lower case. Since the outer peripheral edge of the wafer 1 is in contact, the contact portion is a circular line contact. After the wafer 1 is placed on the lower case 71, an eight-hand retainer (presser) 73 is placed on the upper surface of the wafer (the surface of the wafer facing the lower case is the lower surface and the opposite surface is the upper surface). . The retainer 73 has a conical shape whose center is convex upward, and only the tip of the retainer's hand is in contact with the wafer. The retainer has a leaf spring structure, that is, an elastic structure. When the upper case 74 is fixed together with the lower case 71, the center portion of the retainer 73 is pressed by the top plate portion 77 of the upper case 74. The wafer 1 is fixed to the wafer case by pressing the wafer 1 with the eight leading ends of the retainer 73.
JP 2006-332278 A

  In the case of a single wafer type wafer case using a conventional eight-hand retainer as shown in FIG. 7, the upper and lower wafer cases and the eight-hand retainer have a simple structure and are easy to handle. There is. On the other hand, as described above, the lower surface of the wafer is in line contact with the inclined surface of the bottom plate of the lower case at the outer periphery of the wafer, and the upper surface of the wafer is in contact with the tip of the hand of the eight-hand retainer. The contact parts of do not match. For this reason, the force applied to the wafer from the lower case and the force applied to the wafer from the eight-hand retainer are separated from each other by the fulcrum of the force and are not uniform within the wafer. When the wafer was thicker than 300 μm, the strength of the wafer was sufficient and there was no problem of damage or breakage of the wafer. However, when the wafer was thinned to 20 μm to 200 μm, the strength of the wafer was reduced. The wafer may be damaged by the non-uniform force in the wafer, or the wafer may be locally or non-uniformly distorted to break the wafer. Such a thinned wafer becomes very brittle and requires careful handling. Furthermore, recent devices such as semiconductors have a very fine and complicated structure, and therefore the generation of a slight non-uniform force in the wafer affects the characteristics and reliability of the semiconductor devices.

  Further, in order to suppress the distortion of the wafer, even in the case of the wafer case having the structure for supporting the central portion of the wafer described above, the central portion of the opposite surface cannot be pressed (an element such as a semiconductor is usually formed on the opposite surface). Thus, as in the case of the eight-handed retainer / wafer case, the contact portions of the upper surface and the lower surface of the wafer do not coincide with each other, so that the force applied to the wafer is not uniform within the wafer. Therefore, when the wafer is thinned to 20 μm to 200 μm, the same problem as in the case of the eight-hand retainer / wafer case occurs.

  In particular, the present invention relates to a wafer case that can accommodate a thin and fragile wafer without damage or breakage. In order to solve the above-described problems, the present invention relates to the peripheral edge of a wafer from the upper and lower surfaces of the wafer. The structure is such that the parts are pressed evenly, and the part inside the peripheral edge of the wafer, that is, the element forming part in the wafer is not pressed. That is, the element forming portion in the wafer is in a floating state without contacting any portion in the wafer case. Further, the wafer pressing portion on the upper surface of the wafer and the wafer pressing portion on the lower surface of the wafer are almost at the same position on the upper surface of the wafer and the lower surface of the wafer. The portion where the applied force from above and the force from below are offset increases, and the stress in the wafer due to wafer fixing decreases. Thus, damage to the wafer is not generated, and the wafer is not damaged or broken.

Specifically, the following means are used.
(1) Wafer holders having portions for pressing the wafer peripheral edge on the upper and lower surfaces of the wafer are set on the upper and lower sides of the wafer case, and the wafer peripheral edge is sandwiched by the wafer holder to uniformly hold the wafer peripheral edge.
(2) The upper wafer retainer and the lower wafer retainer have a structure in which the contact portions of the upper surface and the lower surface of the wafer peripheral portion coincide with each other, and have the same contact (support) area on the upper and lower surfaces of the wafer in the wafer peripheral portion.
(3) The upper wafer retainer and the lower wafer retainer have an elastic shape or structure (for example, a shape having a cross section at least bent (for example, a U-shaped, V-shaped, N-shaped, W-shaped cross section). , Z-shape) and inclined shape).
(4) The upper wafer retainer and the lower wafer retainer are made of an elastic material (for example, rubber or foam).
(7) The pressing area at the wafer peripheral edge is in the range of 0.1 mm to 5 mm from the wafer outer peripheral edge.
(8) The holding area of the wafer peripheral edge is at least half of the wafer peripheral edge. (Preferably, the entire periphery of the wafer)
(9) The lower wafer retainer has a size and shape that fits smoothly into the lower case.
(10) The wafer holder can be removed at any time and can be cleaned as appropriate.
(11) The material of the portion that does not contact the wafer and the portion that contacts the wafer may be different.

By the above means, the present invention has the following effects.
(1) Since the upper wafer retainer and the lower wafer retainer contact only the peripheral portions of the upper and lower surfaces of the wafer, there is no contact with the element area within the wafer, and no force acts on the wafer element area. There is no damage at all, and the electrical characteristics and physical characteristics of the elements in the wafer are not affected.
(2) At the peripheral edge of the wafer upper and lower surfaces, the upper wafer retainer and the lower wafer retainer are in uniform contact with the upper and lower surfaces of the wafer (periphery), and the force acting on the wafer upper and lower surfaces generated by the retainer acts equally. The ratio of canceling each other increases. As a result, the force applied to the wafer becomes uniform, and the stress in the wafer due to the wafer fixing is reduced, so that the wafer is neither damaged nor damaged.
(3) Since the upper wafer retainer and the lower wafer retainer have a shape and structure with elasticity, the force exerted on the wafer from the upper wafer retainer and the lower wafer retainer does not increase more than necessary. As a result, the wafer is not damaged and the wafer is not damaged.
(4) Since the upper wafer press and the lower wafer press are made of an elastic material, the force exerted on the wafer from the upper wafer press and the lower wafer press does not increase more than necessary. As a result, the wafer is not damaged and the wafer is not damaged.
(5) The contact area between the upper wafer retainer and the lower wafer retainer and the wafer is not larger than necessary, and the upper wafer retainer and the lower wafer retainer are not in contact with the element area in the wafer. For example, the contact area is within a range of 0.1 to 5 mm from the outer peripheral edge of the wafer. Therefore, no damage is given to the in-wafer element region, and no in-wafer element is damaged.
(6) When there is an opening in a part of the contact area between the wafer presser and the wafer upper and lower surfaces at the peripheral edge of the wafer, since the contact areas of the wafer upper and lower surfaces coincide with each other, the same effect as the above (2) can be obtained. is there.
(7) A wafer case set (wafer case + wafer presser) that can securely fix a wafer at a very low cost can be used because a wafer case having a simple shape (separable vertically) can be used. Can be provided.
(8) Since the wafer retainer has a simple structure and can be separated from the wafer case, the wafer retainer can be used repeatedly and can be easily cleaned. Since not only the wafer holder but also the wafer case has a simple structure, it can be easily cleaned. As a result, the inside of the wafer case can always be kept clean, so that the wafer is not contaminated.

  The present invention relates to a wafer case having a wafer presser that can be safely and securely pressed on the upper and lower surfaces of a wafer and is disposed inside an upper and lower wafer case that can be separated into two upper and lower parts. .

  As described above, in the conventional single wafer type wafer case, when the wafer is pressed and fixed, the portions that hold the wafer upper and lower surfaces differ between the wafer upper and lower surfaces. For this reason, since the force exerted on the wafer from the wafer presser or the like is not uniform within the wafer, when the wafer thickness is reduced to 20 to 200 μm, the wafer may be damaged or the wafer may be damaged. However, the present inventor has found that by making the portions that hold the upper and lower surfaces of the wafer coincide with each other on the upper and lower surfaces of the wafer (the same area), the wafer is hardly damaged or broken. This is because the force acting on the upper surface of the wafer from the upper wafer retainer and the force acting on the lower surface of the wafer from the lower wafer retainer work equally, and the ratio of mutual cancellation of the forces increases. This is because the force becomes uniform and the stress in the wafer due to the wafer fixing becomes small.

  Furthermore, in order to reliably and reliably suppress the force exerted on the wafer from the wafer retainer, the wafer retainer is provided with elastic performance, that is, the structure of the wafer retainer is made elastic, or the wafer retainer is It has been found that the effect of preventing damage to the wafer and the breakage of the wafer can be dramatically improved by configuring the material with an elastic material.

In the following, description will be given based on specific examples.
FIG. 1 (FIGS. 1A to 1C) is a view showing a first embodiment of the present invention, and is a hollow disk-shaped wafer retainer and a U-shaped (or V-shaped) annular wafer retainer having an inclined surface. It is a figure showing the wafer case which has. FIG. 1A is a diagram illustrating a mounting relationship between a wafer mounted on a wafer case and a wafer presser. FIG. 1B is a side sectional view showing a state in which the wafer is placed in the wafer case. FIG. 1C is an enlarged view of a part of FIG. 1B so that the state when the wafer is fixed by the upper wafer press and the lower wafer press can be clearly understood.
The wafer case 10 includes an upper case 14 and a lower case 11 that are separable up and down. An upper wafer retainer 13 and a lower wafer retainer 12 are disposed in the wafer case 10, and the wafer 1 has an upper wafer retainer 13 and a lower wafer retainer. It is sandwiched between the pressers 12. The lower case 11 includes a bottom plate portion 15, a cylindrical side wall portion (lower case side wall portion 16) surrounding the bottom plate outer peripheral portion, and a (lower case) outer peripheral foot portion 19. The upper case 14 includes an (upper case) top plate portion 17 and a cylindrical side wall portion (upper case side wall portion 18) surrounding the outer periphery of the top plate portion.

In FIG. 1A, the bottom plate portion 15 of the lower case 11 has a conical shape inclined downward toward the central portion. The side sectional view of FIG. 1B well represents this inclined state. Lower case side wall portion 16 has a cylindrical shape, the lower the wafer presser 12 is fabricated to fit in well contact with the boundary portion of the lower case side wall portion 16 and the bottom plate portion 15. The wafer 1 also fits inside the cylindrical lower case side wall 16 and is placed on the lower wafer retainer 12.

Next, the upper wafer holder 13 is placed on the wafer 1. The upper wafer retainer 13 is manufactured so as to be in contact with the lower wafer retainer 12. Next, the upper case 14 and the lower case 11 are fixed together with the upper case 14 together with the lower case 11. Since the inside of the side wall portion (upper case side wall portion 18) of the upper case 14 is formed so as to surround the entire outer periphery of the lower case side wall portion 16, the upper case 14 and the lower case 11 can be fixed. When the lower wafer holder 12, the wafer 1 and the upper wafer holder 13 are naturally placed inside the lower case 11 (adapted to gravity and placed without gaps), and then the upper case 14 is combined with the lower case 11 In addition, the uppermost portion of the upper wafer retainer 13 is fabricated so as to contact the inner side of the top plate portion 17 of the upper case 14. Further, the lower wafer retainer 12 and the upper wafer retainer 13 are fabricated so as to contact only the peripheral edge of the wafer. Further, the lower wafer presser 12 and the upper wafer presser 13 are fabricated so as to hold the wafer in the entire region of the wafer peripheral portion. As a result, the wafer 1 is sandwiched and pressed between the lower wafer holder 12 and the upper wafer holder 13 at the peripheral edge of the wafer, so that the wafer 1 is securely fixed to the wafer case 10. When the uppermost part of the upper wafer presser 13 protrudes from the uppermost part of the lower case side wall part 16 of the lower case 11, even if the top plate part 17 is further above the uppermost part of the lower case side wall part 16, the top plate The unit 17 presses the upper wafer holder 13. However, when the uppermost portion of the upper wafer retainer 13 does not protrude from the uppermost portion of the lower case side wall portion 16 of the lower case 11, the top plate 17 contacts the uppermost portion of the upper wafer retainer 13 at the top plate portion 17. The contact portion of the portion 17 is made lower than the uppermost portion of the lower case side wall portion 16 of the lower case 11 so as to be in contact with the uppermost portion of the upper wafer retainer 13, and the top plate portion 17 presses the upper wafer retainer 13. To be able to. Alternatively, the upper wafer pressing contact portion may be attached to the top plate portion 17 for this purpose.

In the first embodiment, as can be seen from FIGS. 1A and 1B, the lower wafer retainer 12 has an annular shape with a U-shaped or V-shaped cross section. Open side of the U-shape or V-shape is in contact with the inside of the lower case side wall portion 16, it is arranged to fit. This U-shaped or V-shaped structure is a kind of elastic structure, and one end of the U-shaped or V-shaped (when pushed by the wafer 1) elastically deforms the U-shaped or V-shaped portion. On the other hand, the upper wafer presser 13, as can be seen from FIGS. 1A and 1B, angled center side is a notched circular plate shape to the center upwards. The disk-shaped upper wafer retainer 13 having an inclination also has a kind of elastic structure, and a hollow disk in which the upper portion of the upper wafer retainer 13 is inclined (when pressed by the top plate portion 17 of the upper case 14). The shape is elastically deformed. As described above, when the upper wafer retainer 13 is placed in conformity with the lower case 11, the uppermost portion of the upper wafer retainer 13 usually protrudes upward from the uppermost portion of the lower case sidewall 16. Accordingly, when the upper case 14 is fixed together with the lower case 11, the upper portion of the upper wafer retainer 13 is pushed and elastically deformed by the top plate portion 17 of the upper case 14, and the force pushed by the top plate portion 17 is increased. Then, the wafer 1 is pressed at the contact portion between the wafer 1 and the upper wafer holder 13. Further, the force pressing the wafer 1 elastically deforms the lower wafer retainer 12 at the contact portion between the wafer 1 and the lower wafer retainer 12.

  FIG. 1C shows this state in an enlarged manner so that it can be clearly understood. As described above, since the upper wafer retainer 13 is inclined upward toward the center portion, the upper case retainer 17 in the contact portion 3 between the upper case retainer 17 and the upper wafer retainer 13 is the upper wafer retainer 13. Press. The upper wafer retainer 13 is pushed downward by the upper case top plate portion 17 and elastically deformed. At the same time, the pressing force from the upper case top plate portion 17 is transmitted to the contact portion 2 between the wafer 1 and the wafer retainer, and the contact portion 2 , The wafer 1 is sandwiched and fixed firmly by the upper wafer holder 13 and the lower wafer holder 12. As can be seen from this figure, at least one part (including the entire contact part) of the contact portion between the upper wafer retainer 13 and the wafer 1 is in a relationship between the front and back of the contact portion between the lower wafer retainer 12 and the wafer 1. It overlaps on the upper and lower surfaces of the wafer. That is, at least one part (including the entire contact part) of the contact portion between the upper wafer retainer 13 and the wafer 1 is the same position or substantially the same in the contact portion between the lower wafer retainer 12 and the wafer 1, the wafer upper surface, and the wafer lower surface. In position. Accordingly, the force that pushes the wafer 1 downward from the upper wafer retainer 13 and the force that pushes the wafer 1 upward from the lower wafer retainer 12 increase in proportion to each other, and the force exerted on the wafer becomes uniform. This represents that the shearing force on the wafer or the force other than the direction perpendicular to the wafer surface becomes very small. That is, since almost no force acts on the wafer inner area other than the contact portion 2 between the wafer 1 and the upper wafer holder 13 and the lower wafer holder 12, particularly the element area in the wafer, the wafer is not damaged. Of course, the wafer is not damaged.

  1B and 1C, the wafer 1 appears to be in point contact with the upper wafer retainer 13 and the lower wafer retainer 12, but the upper wafer retainer 13 and the lower wafer retainer 12 have an elastic structure. Since the wafer 1 is also an elastic body made of an elastic material, the wafer 1 is actually in line contact with the upper wafer retainer 13 and the lower wafer retainer 12 (because it is disk-shaped or annular, Is in surface contact). The larger the contact portion, the smaller the force per unit area at the contact portion, so that the damage to the contact portion of the wafer 1 is reduced. However, if the contact portion is large, it will be in contact with the element portion in the wafer, which is not preferable. Any contact area that can hold the wafer 1 reliably can be used. However, when an element is also formed within 5 mm from the outer peripheral portion of the wafer, the upper wafer press 13 and the upper wafer press 13 and the contact portion 2 between the wafer 1 and the upper wafer press 13 and the lower wafer press 12 are located outside of the device. The size and material of the lower wafer retainer 12 are adjusted. For example, the inclination angle, diameter, size, shape, thickness of the upper wafer retainer 13 and the amount of protrusion from the uppermost portion of the lower case side wall portion 16 may be adjusted in accordance with the contact area. Further, the material of the upper wafer retainer 13, in particular, the elastic modulus may be changed. For the lower wafer retainer 12, for example, the U-shaped or V-shaped opening angle, shape, size, thickness, and material may be adjusted according to the contact area.

  FIG. 2 (FIGS. 2A to 2C) is a diagram showing a second embodiment of the present invention. In the second embodiment, the upper wafer retainer and the lower wafer retainer are in contact with the peripheral edge of the wafer on a flat surface. FIG. 2A is a diagram showing a mounting relationship between a wafer mounted on a wafer case and a wafer presser. FIG. 2B is a side sectional view showing a state where the wafer is placed in the wafer case. FIG. 2C is an enlarged view of a part of FIG. 2B so that the state when the wafer is fixed by the upper wafer press and the lower wafer press can be clearly understood.

As can be seen from FIG. 2A, the mounting relationship between the wafer mounted on the wafer case and the wafer holder is the same as in FIG. 1A. However, the lower wafer holder 22 and the upper wafer holder 23 are different from those of the first embodiment. As can be seen from FIG. 2B, the portion of the lower wafer retainer 22 that contacts the wafer is the outer peripheral surface of the wafer peripheral portion. That is, the lower wafer retainer 22 has an annular shape with an L-shaped cross section, a wafer receiving portion 22B having a flat upper surface from the outer end portion toward the center, and an upright portion that rises upward from the outer end portion. Have. The wafer 1 fits inside the upright portion of the lower wafer retainer 22 and is placed on the wafer receiving portion 22B. Further, the upper wafer holder 23 has a disk structure having a cylindrical side wall portion on the outer peripheral portion. The outer edge of the cylindrical side wall portion fits inside the standing portion of the lower wafer retainer 22 . There is a flat portion on the lower end surface of the cylindrical side wall portion, and the wafer placed on the wafer receiving portion 22B is pressed from above. When the upper case 24 is not placed, the ceiling plate 23A of the upper wafer retainer 23 normally protrudes above the uppermost portion of the lower case side wall portion 26. Accordingly, when the upper case 24 is arranged and fixed together with the lower case 21, the ceiling plate 23 </ b> A of the upper wafer retainer 23 is pushed by the upper case 24. The force acts on the side wall portion 23B of the upper wafer retainer 23, and on the contact surface between the wafer 1 and the flat portion of the side wall portion 23B of the upper wafer retainer 23 (thus becoming a flat surface), the side wall portion 23B of the upper wafer retainer 23 is provided. The wafer 1 is pressed downward on the contact surface at the peripheral edge of the wafer 1 by the force acting on the wafer 1. The force further presses the wafer receiving portion (flat portion) 22B ( shown in FIG. 2C ) of the lower wafer retainer 22. Thus, the wafer 1 is sandwiched and fixed between the lower wafer holder 22 and the upper wafer holder 23.

FIG. 2C is an enlarged view of this state. The lower wafer holder 22 having an L-shaped cross section has a structure that fits inside the lower case side wall portion 26 and the bottom plate portion 25 of the lower case 21. The peripheral portion of the wafer 1 is placed on the flat portion 22B of the lower wafer retainer 22 and contacts the flat portion of the side wall portion 23B of the upper wafer retainer 23. In this case, the contact surface between the wafer 1 and the lower wafer retainer 22 is desirably the same region as the contact surface between the wafer 1 and the upper wafer retainer 23. By making it so, the force acting on other regions in the wafer, especially the region where the element exists, becomes very small. As a result, the wafer is not damaged or broken.

  The ceiling plate 23A of the upper wafer retainer 23 may be structured to be inclined upward toward the center. This structure is a kind of elastic structure. In this case, a part of the ceiling plate 23A protrudes above the uppermost portion of the lower case side wall portion 26, and the protruding portion of the ceiling plate 23A is pushed by the top plate portion 27 of the upper case 24. Acts on the side wall 23B of the upper wafer retainer 23.

  When the ceiling plate 23A of the upper wafer retainer 23 is a flat plate, the entire ceiling plate 23A protrudes above the uppermost portion of the lower case side wall portion 26, so that the upper wafer retainer 23 and the lower wafer retainer 22 are elastic. By deforming, the wafer 1 is fixed. For example, since the upper wafer retainer 23 and the lower wafer retainer 22 are made of an elastic material, these elastic materials are deformed by the pressing.

  In FIG. 2 showing the second embodiment, the ceiling plate 23A of the upper wafer retainer 23 is shown as a complete disc shape, but may be a hollow disc shape or an eight-handed shape. It may be.

  FIG. 3 is a view showing a third embodiment of a wafer case having a lower wafer presser and an upper wafer presser each having a U-shaped (or V-shaped) cross section. In the third embodiment, only a side sectional view is shown so that the structure can be clearly understood. The wafer 1 is sandwiched and fixed between the lower wafer holder 32 and the upper wafer holder 33. When the upper case 34 is not fixed, a part of the U-shaped (or V-shaped) upper wafer presser 33 protrudes from the uppermost part of the lower case side wall 36, and the lower case 31 and the upper case 34 are aligned. Then, the U-shaped (or V-shaped) upper wafer presser 33 is pressed by the top plate portion 37 of the upper case 34. Since the U-shaped (or V-shaped) upper wafer retainer 33 is a kind of elastic structure, one end of the U-shaped (or V-shaped) is pressed, and the U-shaped (or V-shaped) shape is elastically deformed. Press. Further, a U-shaped (or V-shaped) lower wafer presser 32 is pushed through the wafer 1. Since the U-shaped (or V-shaped) lower wafer presser 32 is also a kind of elastic structure, one end thereof is pressed and the U-shaped (or V-shaped) shape is elastically deformed. Press upward. By making the contact portion between the upper wafer retainer 33 and the wafer 1 and the contact portion between the lower wafer retainer 32 and the wafer 1 in the same region within the wafer, the forces pressing the wafer 1 (the upper wafer retainer is The force pushing the upper surface and the force by which the lower wafer press pushes the lower surface of the wafer 1 can be made uniform and the ratio of canceling each other can be increased. As a result, even if the wafer is as thin as 20 μm to 200 μm, the area other than the contact portion 4 of the wafer 1, particularly the element area, is not damaged and the wafer is not damaged. Note that when the upper case 34 and the lower case 31 are fixed, the upper case 34 presses the upper wafer presser 33 as described above. The upper portion does not necessarily coincide with or lower than the uppermost portion of the lower case side wall portion 36. The uppermost position of the upper wafer presser 33 may be determined by the combined position of the upper case side wall 38 and the lower case side wall 39. Alternatively, it may be determined by a reaction force from the upper wafer presser 33, or may be determined by suppression of a stopper or the like.

  FIG. 4 shows a fourth case where the upper wafer retainer has a U-shaped (or V-shaped) cross section, and the lower wafer retainer has a hollow disk shape having a structure inclined toward the lower center. It is an embodiment. In the fourth embodiment, only a side sectional view is shown so that the structure can be clearly understood. Both structures are a kind of elastic structure. The upper wafer holder 43 is the same as that of the third embodiment. The wafer 1 is in contact with the upper wafer retainer 43 and the lower wafer retainer 42 at the contact portion 5. The force passing through the wafer 1 from the upper wafer holder 43 acts downward on the contact surface between the lower wafer holder 42 and the wafer 1. Since the lower wafer holder 42 is also a kind of elastic structure, the lower wafer holder 42 is elastically deformed downward. The contact portion between the wafer 1 and the upper wafer retainer 43 and the contact portion between the wafer 1 and the lower wafer retainer 42 are fabricated to be the same portion within the wafer. As a result, the force acting on the wafer region other than the contact portion, particularly the element region, is very small, so that the wafer is not damaged or damaged.

  FIG. 5 shows a fifth embodiment in which the upper wafer retainer and the lower wafer retainer have a hollow disc shape whose cross section is inclined toward the center. In the fifth embodiment, only a cross-sectional side view is shown so that the structure can be clearly understood. It can be considered that the upper wafer press shown in the first embodiment and the lower wafer press shown in the fourth embodiment are combined. The upper wafer retainer 53 has a hollow disk shape that is inclined upward in the center, but a part of the upper wafer retainer 53 protrudes above the lower case side wall 56. When the lower case 51 is fixed together with the upper case 54, the top plate portion 57 of the upper case 54 pushes the protruding portion of the lower case side wall portion 56 downward. The upper wafer retainer 53 is elastically deformed downward, but the force acts on the contact surface between the wafer 1 and the upper wafer retainer 53 to push the wafer 1 downward. (The contact portion between the wafer 1 and the upper wafer retainer 53 and the lower wafer retainer 52 is 6.) The contact portion between the wafer 1 and the upper wafer retainer 53 and the contact portion between the wafer 1 and the lower wafer retainer 52 are: Since it is fabricated so as to be the same part within the wafer, this force acts on the lower wafer retainer 52 via the wafer 1, and the lower wafer retainer 52 is elastically deformed downward. At this time, the force acting on the wafer 1 from the lower wafer retainer 52 and the force acting on the wafer 1 from the upper wafer retainer 53 increase in proportion to cancel each other, and the overall force exerted on the wafer becomes very small. As a result, since the force acting on the wafer area other than the contact portion 6, particularly the element area, becomes very small, the wafer is not damaged or the wafer is not damaged.

  FIG. 6 is a diagram showing another wafer presser. The conventional eight-handed wafer retainer shown in FIG. 7 is improved to be compatible with the present invention. That is, the structure is such that when the eight-handed tip is connected in a circular shape and the wafer is pressed, the eight-handed circular tip contacts the peripheral edge of the wafer. The wafer presser 61 can be used as an upper wafer presser or a lower wafer presser as in the first to fifth embodiments described so far. It may be used for both the upper wafer presser and the lower wafer presser, or it may be used only for one side and another type of presser for the other. The eight-handed wafer retainer 61 is inclined from the eight-handed tip (outer peripheral portion of the wafer retainer 61) 63 toward the center. At this time, when the wafer is fixed, it is a part of the eight-handed tip (outer peripheral part of the wafer presser 61) 63 that comes into contact with the wafer, but the contact part is in contact with the other wafer surface. It is produced so as to match the part. As a result, the central portion 64 of the wafer holder 61 is pushed downward by the top plate portion of the upper case and is elastically deformed, and the force from the top plate portion pushes the wafer from the outer peripheral portion of the wafer holder 61, The wafer is fixed between the lower wafer presser. As a result, as described above, no force acts on the area other than the contact area in the wafer, so that the wafer is not damaged or broken. The same effect can be obtained with a completely disc-like shape that is inclined toward the center instead of the eight-handed shape.

  It should be noted that although “eight hands” is used, it does not mean that there are literally eight hands, but it means that the hands are divided into several (including eight). Yes.

  Although several embodiments have been described above, the wafer press described so far may be used on the upper side or may be used on the lower side. What is important is that only the wafer peripheral edge is in contact with the wafer retainer, and the other wafer area is not in contact with any part of the wafer case, and the upper wafer retainer is in contact with the wafer and the lower wafer retainer is in contact with the wafer. By making the contact portions coincide (or substantially coincide) within the wafer, the force acting on the wafer at the contact portion becomes very small. That is, the structure is such that a force is evenly applied to the wafer from above and below the wafer. As a result, since no force is applied to the wafer area other than the contact portion (or the acting force is very small), the wafer is not damaged and the wafer is not broken.

Although the contact portion between the wafer and the wafer retainer is preferably circular, the contact between the upper wafer retainer and the upper surface of the wafer is also possible when the contact portion between the lower wafer retainer and the lower surface of the wafer is a part of the peripheral edge of the wafer. As described above, it is important to make the portion coincide with or substantially coincide with the contact portion between the lower wafer pressing member and the lower surface of the wafer.
There are various structures other than those described in this specification as the elastic structure of the wafer retainer.

  For example, an annular wafer retainer having a W-shaped (E-shaped) or N-shaped (Z-shaped) cross section can be used. A ring-shaped presser can also be used. Furthermore, it goes without saying that other elastic structures are also conceivable.

  Furthermore, when the present invention is used for a wafer whose thickness is as thin as 20 μm to 200 μm or 50 μm to 300 μm, the damage of the wafer is drastically compared with the case where a wafer case having a conventional method or structure is used. As described above, there is an effect of preventing damage and damage, but it goes without saying that it can be used for a wafer thicker than the above. Although not described in detail, since it is not in contact with the region inside the wafer other than the peripheral portion of the wafer, it is possible to hold the wafer in the wafer case with the front and back sides reversed.

  It is desirable to use an elastic polymer material, which is a resin having elasticity, as a material for the wafer holder. Since the material is elastically deformed, the force acting on the wafer can be reduced. In addition, when receiving an impact from the outside, a buffering effect on the wafer can be expected. Elastic polymer materials include thermoplastic elastomers, foamed polymers, and fluororesins. As thermoplastic elastomers, PET (polyethylene terephthalate), PEE (polyester elastomer), PEEK (polyether ether ketone), PBTE (polybutylene terephthalate elastomer), PBNE (polybutylene naphthalate), PPE (polyphenylene ether), PUE (polyurethane) Elastomer). Examples of the fluororesin include PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxyalkane). Examples of the foamed polymer include foamed PET (polyethylene terephthalate), foamed PE (polyethylene), foamed PU (polyurethane), and foamed PS (polystyrene). Also, polymer materials such as PC (polycarbonate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PP (polypropylene), ABS (acrylonitrile butadiene styrene) resin and the like can be used. The above polymer materials may be used singly or in plural. It is also possible to use the above-mentioned polymer material for the portion in contact with the wafer and another material such as an inorganic material such as metal or glass for the other portions. Further, a wafer retainer in which an inorganic material such as metal or glass is covered with the above polymer material can be used. For example, a wafer retainer in which a metal is coated with the above polymer material has excellent characteristics of the metal such as high elasticity and durability, and excellent characteristics of the polymer material such as flexibility and cleanliness. Examples of the metal include iron, nickel, cobalt, copper, zinc, platinum, magnesium, titanium, chromium, manganese, tungsten, etc., and alloys containing these alloys and other trace elements. In particular, a wafer retainer in which only the portion in contact with the wafer is covered with the polymer material can be used.

  For the upper case and the lower case, an existing wafer case can be used. The upper wafer retainer and the lower wafer retainer according to the present invention may be manufactured so as to be compatible with those cases and the wafers (size, thickness, shape, etc.) accommodated therein. In the present invention, since the wafer case does not directly contact the wafer, a wafer case made of metal, alloy, glass, SiC or the like can also be used. Therefore, the wafer case using these materials can be made extremely strong.

  The present invention can be applied not only to a wafer but also to a single-wafer case that can store a thin and / or fragile plate material. Therefore, the present invention is not limited to a process such as a semiconductor, but a display body forming process such as a liquid crystal process or an organic EL (electroluminescence). It can also be applied to. In the present embodiment, the description has been made on the circular wafer, but it is apparent that the wafer can be applied to a rectangular shape and other shapes instead of the circular shape.

  Furthermore, although the present invention has been described for a single wafer type wafer case that can be stored one by one, regardless of the word "single wafer type", if this wafer case is stacked and fixed in multiple stages, a large number of wafers can be stored. It is also clear that the wafer case becomes.

  The present invention can be used in wafer processing, transportation / conveyance processes and wafer storage in semiconductor processes and the like.

FIG. 1A is a diagram illustrating a first embodiment of the present invention, and is a diagram illustrating a mounting relationship between a wafer mounted on a wafer case and a wafer presser. FIG. 1B is a side sectional view showing a state in which a wafer is placed in a wafer case, showing the first embodiment of the present invention. FIG. 1C is a diagram showing a first embodiment of the present invention and is an enlarged view of a part of FIG. 1B. FIG. 2A is a diagram illustrating a second embodiment of the present invention, and is a diagram illustrating a mounting relationship between a wafer mounted on a wafer case and a wafer presser. FIG. 2B is a side sectional view showing a state in which the wafer is placed in the wafer case, showing the second embodiment of the present invention. FIG. 2C is a diagram showing a second embodiment of the present invention, and is an enlarged view of a part of FIG. 2B. FIG. 3 is a view showing a third embodiment of a wafer case having a lower wafer presser and an upper wafer presser each having a U-shaped (or V-shaped) cross section. FIG. 4 shows a fourth case where the upper wafer retainer has a U-shaped (or V-shaped) cross section, and the lower wafer retainer has a hollow disk shape having a structure inclined toward the lower center. It is an embodiment. FIG. 5 shows a fifth embodiment in which the upper wafer retainer and the lower wafer retainer have a hollow disc shape whose cross section is inclined toward the center. FIG. 6 is a diagram showing another wafer presser. FIG. 7A is a perspective view showing a conventional single wafer type wafer case. FIG. 7B is a side sectional view of the conventional single wafer type wafer case shown in FIG. 7A.

Explanation of symbols

1 ... wafer, 2, 4, 5, 6 ... contact portion between wafer 1 and wafer retainer,
3 ... Contact portion between the top plate and the upper wafer holder,
10 ... wafer case, 11 ... lower case,
12 ... Lower wafer retainer, 13 ... Upper wafer retainer,
14 ... upper case, 15 ... bottom plate part, 16 ... lower case side wall part,
17 (upper case) top plate part, 18 ... upper case side wall part,
19 ... (lower case) outer peripheral foot, 21 ... lower case, 22 ... lower wafer holder,
22B: Lower wafer retainer receiving portion, 23: Upper wafer retainer,
23A ... (upper wafer press) ceiling plate, 23B ... upper wafer press side wall,
24 ... Upper case, 25 ... Bottom plate part, 26 ... Lower case side wall part,
27 ... (upper case) top plate part, 28 ... upper case side wall part,
29 (lower case) outer peripheral foot, 30 ... wafer case,
31 .. Lower case, 32 .. Lower wafer holder, 33 .. Upper wafer holder,
34 ... upper case, 35 ... bottom plate part, 36 ... lower case side wall part,
37 ... (upper case) top plate part, 38 ... upper case side wall part, 39 ... (lower case) outer peripheral foot part, 41 ... lower case, 42 ... lower wafer holder, 43 ... upper wafer Hold down,
44 ... Upper case, 45 ... Bottom plate part, 46 ... Lower case side wall part,
47 ... (upper case) top plate part, 48 ... upper case side wall part, 49 ... (lower case) outer peripheral foot part, 51 ... lower case, 52 ... lower wafer presser,
53 ... Upper wafer holder, 54 ... Upper case, 55 ... Bottom plate,
56 ... lower case side wall, 57 ... (upper case) top plate, 58 ... upper case side wall,
59 ... (lower case) outer peripheral foot, 61 ... wafer holder,
63 .. Wafer holder outer peripheral part, 64... Wafer holder center part,
71 ... Lower case, 73 ... Retainer (eight-handed wafer presser), 74 ... Upper case,
75 (lower case) bottom plate, 77 (upper case) top plate,

Claims (6)

A single wafer type wafer case comprising a lower case, a lower wafer presser, an upper case and an upper wafer presser, each of which can be separated,
The lower case has a cylindrical lower case side wall provided around the bottom plate portion in the conical bottom plate portion inclined to the central portion downward and the bottom plate portion outer peripheral portion,
The upper case has a top plate and a cylindrical upper case side wall provided around the top plate,
The inner side of the upper case side wall has a structure surrounding the entire outer periphery of the lower case side wall,
The lower wafer presser is disposed the bottom plate portion outer peripheral portion and the side wall portion inside the lower case to fit in contact with
The upper wafer press is placed on the upper surface of the wafer placed on the lower wafer press inside the lower case side wall,
The upper case top plate portion presses the upper wafer presser,
The wafer is clamped by the lower wafer press and the upper wafer press in the entire area of the peripheral edge of the wafer,
A single wafer type wafer case characterized in that a wafer inner region inside a wafer peripheral portion is held without any contact. The lower wafer retainer has an annular shape with an L-shaped cross section, and has a wafer receiving portion having a flat upper surface extending from the outer end portion of the lower wafer retainer in the center direction and an upright standing upward from the outer end portion. 2. The wafer case according to claim 1, wherein the wafer case has a portion, and a wafer end surface fits inside the upright portion. The upper wafer retainer has a cylindrical side wall portion placed on the upper surface of the wafer, and an outer peripheral surface of the upper wafer retainer cylindrical side wall portion fits inside an upright portion of the lower wafer retainer. The wafer case according to claim 2 . The upper wafer presser and / or the lower wafer presser is characterized in that the facing wafer to the wafer casing center a disk shape in which the center side is inclined in the opposite direction is cut out, according to claim 1 wafer case according to. 4. The wafer case according to claim 2 , wherein a peripheral edge portion of the lower surface of the wafer is placed and supported on a wafer receiving portion of the lower wafer presser. The wafer case according to claim 3 , wherein a peripheral edge portion of the upper surface of the wafer is pressed downward in contact with a flat portion of a side wall portion of the upper wafer presser.

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