Processing apparatus and method

Abstract

[Problem] To provide a processing apparatus and method for safely processing a wafer in which a bump is formed on the outer face thereof. [Solution] A processing apparatus (10) is provided with a chuck (40) which can hold a raised area (24) of a wafer (20), a support ring (30) which has a support face (32) for supporting a bent area (26) which extends from the raised area (24) to an outer peripheral area (25) and in which a film (20) is bent, the support ring (30) being able to support the outer peripheral area (25) of the wafer (20), and a chuck table (16), the chuck (40) being housed substantially in the middle of the chuck table (16) and the support ring (30) being housed in the outer periphery of the chuck (40).

Description

Technical Field

[0001] The present invention relates to a processing apparatus and method for processing wafers to be thinner, wherein a plurality of bumps are formed on the outer surface of the wafer. Background Technology

[0002] In the semiconductor manufacturing field, as a device for grinding semiconductor wafers (hereinafter referred to as "wafers") such as silicon wafers into thinner and flatter surfaces, there is a known processing apparatus that presses the grinding surface of a rotating grinding wheel onto the wafer to grind the inner surface of the wafer. During grinding of the inner surface of the wafer, a protective film is adhered to the outer surface of the wafer to protect the wafer and bumps formed on the outer surface.

[0003] When the inner surface of the wafer is finished grinding, a dicing film is adhered to the inner surface of the wafer in a dicing film adhesion apparatus, integrating the wafer with the mounting frame. Next, after peeling off the outer protective film adhered to the outer surface of the wafer, the wafer is diced into a grid pattern. The wafers formed by dicing are picked up and mounted onto the lead frame (for example, see Patent Document 1).

[0004] Figure 8 This is an example of a processing apparatus for grinding the inner surface of a wafer. A wafer 90 has bumps 93 formed on its outer surface 91, and a film 94 is attached to cover the bumps. The wafer 90 is held on a worktable 96 with its inner surface 95 facing upwards, and a grinding wheel 98 grinds the inner surface 95 while the outer periphery of the wafer 90 is supported by a cylinder 97.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: JP Japanese Patent Application Publication No. 2009-206475 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in Figure 8 In the processing apparatus shown, the height difference between the worktable 96 and the cylinder 97 increases according to the height of the bump 93. In a wafer 90 with high bumps, where the height of the bump 93 exceeds 100 μm, the film 94 cannot completely absorb the height difference. The film 94 floats apart from the worktable 96, creating a ring-shaped gap when viewed from above. The thin wafer 90 may break in the part that is not supported in the gap during inner surface grinding.

[0010] Therefore, in order to safely process wafers with bumps formed on the outside, a technical problem arises that needs to be solved, and the object of the present invention is to solve this problem.

[0011] Technical solutions for solving the problem

[0012] To achieve the above objectives, the processing apparatus of the present invention relates to a processing apparatus for grinding the inner surface of a wafer, the wafer comprising a bump region and an outer peripheral region surrounding the bump region, the bump region being obtained by forming bumps on the outer surface of the wafer, wherein a film is adhered to the outer surface, characterized in that the processing apparatus comprises: a chuck capable of holding the bump region of the wafer; a support member having a support surface for supporting a bent region, capable of supporting the outer peripheral region of the wafer, in which the film bends from the bump region to the outer peripheral region; and a chuck stage accommodating the chuck, the support member being accommodated on the outer periphery of the chuck.

[0013] According to this scheme, the curved area of ​​the film is supported by a support member, which is curved in such a way that the height of the bumps is raised from the chuck. Therefore, the film is supported without gaps by the support member and the chuck, so that the bumped wafer can be safely processed without damaging it.

[0014] Furthermore, in the processing apparatus of the present invention, it is preferable that the support member is embedded in the annular groove formed on the outer periphery of the chuck.

[0015] According to this scheme, by setting the support components in a ring shape to surround the chuck, the wafer can be supported over a large area, thus enabling safe processing of the bumped wafer without damaging it.

[0016] Furthermore, in the processing apparatus of the present invention, it is preferable that the aforementioned support member and chuck table are made of materials exhibiting substantially the same coefficient of thermal expansion.

[0017] According to this scheme, the frictional heat generated during wafer processing causes the support components and chuck stage to expand thermally in a roughly uniform manner, thus enabling high-precision wafer processing.

[0018] Furthermore, in the processing apparatus of the present invention, it is preferable that the chuck worktable is provided with a drainage hole that communicates the annular groove with an opening formed on the circumferential surface of the chuck worktable.

[0019] According to this scheme, grinding water and other substances in the annular groove can be discharged to the outside.

[0020] Furthermore, in the processing apparatus of the present invention, it is preferable to also have a cleaning mechanism that sprays a dual fluid toward the outside of the chuck worktable.

[0021] According to this scheme, in a cleaning device that presses hard cleaning stones or the like onto a chuck worktable, the support component protrudes from the chuck, making it impossible to clean the outside of the chuck. In contrast, a dual-fluid system can be used to effectively clean the entire surface of the chuck worktable, which includes the support component and the chuck.

[0022] Furthermore, to achieve the above-mentioned objective, the processing method of the present invention relates to a method for grinding the inner surface of a wafer, the wafer including a bump region and an outer peripheral region surrounding the bump region, the bump region being obtained by forming bumps on the outer surface of the wafer, wherein a film is adhered to the outer surface, the processing method comprising: a step of measuring the shape of a curved region in the film, in which the film bends from the bump region to the outer peripheral region; a step of forming a support surface corresponding to the shape of the curved region on the inner periphery of the upper end face of a support member; and a step of holding the aforementioned... The process includes grinding the outer surface of the chuck with the bump area of ​​the wafer and the outer surface of the chuck stage that houses the chuck to be substantially flat; inserting the support member into the annular groove of the chuck stage formed on the outer periphery of the chuck with the lower end face of the support member facing upward; grinding the lower end face of the support member to a predetermined height from the outer surface of the chuck stage; reversing the support member vertically; and holding the wafer with the support surface supporting the curved area and the upper end face supporting the outer periphery.

[0023] According to this scheme, the support member supports the curved area of ​​the film, which is curved by the amount of the height of the bumps that are raised from the chuck. Thus, the film is supported without gaps by the support member and the chuck, so that the wafer with bumps can be processed safely.

[0024] Furthermore, in the processing method of the present invention, it is preferable that, during the grinding process of the lower end face of the support member, the grinding is performed while measuring the height of the lower end face of the support member relative to the outside of the chuck worktable.

[0025] According to this structure, the support components can be machined with high precision by measuring the height of the lower end face of the chuck table relative to the outside in real time during grinding.

[0026] The effects of the invention

[0027] In this invention, since the film is supported without gaps by the support member and the chuck, it is possible to process it safely without damaging the bumped wafer. Attached Figure Description

[0028] Figure 1A schematic diagram illustrating the general outline of a processing apparatus according to one embodiment of the present invention;

[0029] Figure 2 (a) is a top view of the wafer. Figure 2 (b) is a longitudinal sectional view of the wafer. Figure 2 (c) is an enlarged view of the main part of the wafer;

[0030] Figure 3 (a) is an assembly diagram of the chuck table and support components. Figure 3 (b) is a perspective view of the chuck table with the support components embedded.

[0031] Figure 4 This is a longitudinal sectional view of the supporting component;

[0032] Figure 5 This is a longitudinal sectional view of the chuck table;

[0033] Figure 6 (a) is a schematic diagram showing the grinding of the outer surfaces of the chuck and the chuck table. Figure 6 (b) is a schematic diagram showing the case of grinding the lower end face of the support component. Figure 6 (c) is a schematic diagram illustrating the cleaning process using a two-fluid system;

[0034] Figure 7 (a) is a schematic diagram showing how the wafer is held on the chuck. Figure 7 (b) is an enlarged view of the main part showing how the membrane is supported by the support surface. Figure 7 (c) is a schematic diagram showing the grinding of the inner surface of a wafer;

[0035] Figure 8 This is a longitudinal sectional view showing the structure of a past processing device. Detailed Implementation

[0036] An embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, when referring to the quantity, value, amount, range, etc., of the constituent elements, they are not limited to that specific quantity, except where specifically stated or clearly limited in principle; they may be more than or less than that specific quantity.

[0037] In addition, when referring to the shape and positional relationship of constituent elements, etc., except for cases that are specifically stated or are obviously not so in principle, cases that are substantially similar or analogous to that shape, etc.

[0038] Furthermore, in accompanying drawings, characteristic parts are sometimes enlarged or exaggerated for easier understanding, and the size ratios of constituent elements may not be the same as actual dimensions. Additionally, in sectional views, some section lines of constituent elements are sometimes omitted to facilitate understanding of their cross-sectional structure.

[0039] Towards Figure 1 The processing device 10 shown supplies Figure 2 of (a), Figure 2 (b) shows a silicon wafer 20 with a plurality of wafers C having bumps B formed on its outer surface 23. The processing apparatus 10 includes a film bonding section 11 for bonding a BG film 21 to the wafer 20 and an inner surface grinding section 12 for grinding the inner surface 22 of the wafer 20.

[0040] The inner surface grinding section 12 has an insertion unit 13, an end face grinding unit 14, and an inner surface grinding unit 15.

[0041] The insertion unit 13 inserts the support ring 30 into the annular groove 17 pre-formed in the chuck table 16. Alternatively, the operator may insert the support ring 30 into the annular groove 17 instead of using the insertion unit 13.

[0042] The end face grinding unit 14 uses a grinding wheel 14a to grind the end face of the support ring 30 mounted on the chuck table 16. The end face grinding unit 14 has an in-process gauge 14b, which will be described later.

[0043] The inner surface grinding unit 15 grinds the inner surface 22 of the wafer 20 using a grinding wheel 15a. The inner surface grinding unit 15 has a dual-fluid nozzle 15b with a known structure, which sprays a dual-fluid mixture, miniaturized by high-speed gas, toward the chuck stage 16. Additionally, the inner surface grinding unit 15 has a machining gauge 15c for measuring the thickness of the wafer 20 during inner surface grinding. The inner surface grinding unit 15 can also be configured to function as an end-face grinding unit 14. Furthermore, reference numeral 18 indicates a robot arm that transports the wafer 20, with a BG film 21 attached to the film bonding section 11, to the inner surface grinding unit 15.

[0044] like Figure 2 of (a), Figure 2 As shown in (b), a plurality of wafers C are formed only in the central region 24 of the outer surface 23 of the wafer 20, and bumps B, which serve as electrical contacts, are formed on each wafer C. That is, wafers C and bumps B are not formed in the outer peripheral region 25 of the wafer 20. Hereinafter, the central region 24 will be referred to as the bump region 24.

[0045] A BG film 21 is attached to the outer 23 side of the wafer 20 in a manner that covers the entire surface. The BG film 21 protects the wafer C and bumps B during the inner surface grinding process described later, and prevents grinding water from flowing between the wafer 20 and the BG film 21, thereby contaminating the wafer C and bumps B.

[0046] like Figure 2 (b) Figure 2 As shown in (c), the BG membrane 21 is smoothly curved between the bump region 24 and the outer peripheral region 25, corresponding to the height of the bump B. Hereinafter, the curved region of the BG membrane 21 will be referred to as the curved region 26. The cone angle θ1 in the curved region 26 of the BG membrane 21 is set in the range of about 1 to 10 degrees, corresponding to the height of the bump B, the stiffness of the BG membrane 21, and the width of the outer peripheral region 25, etc.

[0047] like Figure 3 of (a), Figure 3 As shown in (b), a chuck 40 made of a porous material such as alumina is embedded approximately at the center of the outside of the chuck stage 16. The chuck stage 16 has a pipe (not shown) extending from the inside to the outside. The pipe is connected to a vacuum source, compressed air source, or water supply source (not shown). When the vacuum source is activated, the wafer 20 placed on the chuck stage 16 is held by the chuck 40. Conversely, when the compressed air source or water supply is activated, the wafer 20 is released from the chuck 40.

[0048] The support ring 30 can be embedded in an annular groove 17 formed on the outer periphery of the chuck 40. The support ring 30 is formed in a generally cylindrical shape, and its inner diameter is set to be smaller than the outer diameter of the wafer 20. The axial height dimension of the support ring 30 is set such that, when the support ring 30 is embedded in the annular groove 17, the upper end face 31 of the support ring 30 protrudes from the outside of the chuck stage 16 by an amount corresponding to the height of the bump B. In addition, the shape of the support ring 30 is not limited to a cylindrical shape. The support ring 30 can be of any shape as long as it can support the bending region 26 to a degree that the wafer 20 will not break during grinding of the inner surface of the wafer 20 (described later).

[0049] like Figure 4 As shown, the support ring 30 has a support surface 32 that tapers the inner periphery of the upper end face 31. The shape of the support surface 32 corresponds to the shape of the curved region 26 of the BG membrane 21. Specifically, the radial width of the support surface 32 is set to correspond to the radial width of the curved region 26 of the BG membrane 21, and the cone angle θ2 of the support surface 32 is set to correspond to the measured cone angle θ1 of the BG membrane 21. In addition, the lower end face 33 of the support ring 30 is formed substantially parallel to the upper end face 31.

[0050] The support ring 30 is made of a material, such as silicon or plastic, that can be ground by the grinding wheel 14a of the end face grinding unit 14. It is particularly preferably made of a material with a coefficient of thermal expansion approximately the same as that of the chuck table 16, such as alumina ceramic. This ensures that the chuck table 16 and the support ring 30 undergo approximately uniform thermal expansion due to frictional heat during grinding, thus guaranteeing machining accuracy. Furthermore, when using a T-wrench to remove the support ring 30 from the annular groove 17, a threaded hole (not shown) is preferably provided on the upper end face 31 of the support ring 30.

[0051] like Figure 5 As shown, the support ring 30 embedded in the annular groove 17 is secured by screws 50 that engage with threaded holes 16c, which are formed radially inward from the circumferential surface of the chuck table 16. Furthermore, the screws 50 are preferably formed at equal intervals along the circumference of the chuck table 16. Additionally, the annular groove 17 communicates with an opening 16a formed on the circumferential surface of the chuck table 16 via a drain hole 16b. Thus, during internal surface grinding, grinding water is not retained within the annular groove 17 but is drained to the outside.

[0052] Next, the process of grinding the inner surface of the wafer 20 using the processing apparatus 10 will be described based on the accompanying drawings.

[0053] [Grinding Preparation]

[0054] First, the film bonding section 11 bonds the BG film 21 onto the wafer 20. Then, using an external roughness tester or the like (not shown in the figure), the shape (radial length, cone angle θ1, etc.) of the curved region 26 in the BG film 21 bonded to the entire surface of the wafer 20 is measured.

[0055] Next, the inner periphery of the upper end face 31 of the support ring 30 is ground using a grinding device (not shown in the figure) in a manner corresponding to the shape of the measured curved region 26, forming the support surface 32. Furthermore, the grinding device for forming the support surface 32 on the support ring 30 can be, for example, a rotary grinding machine, but is not limited thereto. This rotary grinding machine includes a grinding wheel with a conical surface corresponding to the shape of the support surface 32. While rotating the support ring 30 and the grinding wheel respectively, the conical surface of the grinding wheel is pressed against the inner periphery of the upper end face 31 of the support ring 30 to perform inner diameter machining, thereby forming the support surface 32.

[0056] Then, as Figure 6 As shown in (a), while rotating the grinding wheel 15a and the chuck table 16, the grinding wheel 15a is pressed downward for a predetermined time, thereby grinding the outer surface of the chuck 40 and the outer surface of the chuck table 16 to be substantially flat.

[0057] When the outer surface of the chuck 40 and the outer surface of the chuck table 16 have been ground for a specified time, the grinding wheel 15a and the chuck table 16 are stopped and the grinding wheel 15a is retracted. Then, after cleaning the annular groove 17 as needed, the insertion unit 13 inserts the support ring 30 into the annular groove 17 with the lower end face 33 facing upward.

[0058] After that, as Figure 6 As shown in (b), while rotating the grinding wheel 14a and the chuck table 16, the grinding wheel 14a is pressed onto the lower end face 33, thereby grinding the support ring 30.

[0059] The grinding amount of the support ring 30 is set such that the height of the lower end face 33 relative to the outside of the chuck stage 16 is approximately equal to the distance between the outer surface 23 of the wafer 20 and the top of the bump B, i.e., the height of the step of the BG film 21 between the bump region 24 and the outer peripheral region 25. Therefore, when processing wafers 20 with different bump B heights, the grinding amount of the support ring 30 is changed according to the size of the bump B.

[0060] In addition, the height of the lower end face 33 and the outside of the chuck table 16 is measured using the machining gauge 14b. Based on their difference, the height of the lower end face 33 relative to the outside of the chuck table 16 is measured during machining, thereby enabling the support ring 30 to be machined with high precision corresponding to the height of the bump B.

[0061] When the lower end face 33 is ground to a specified height relative to the outside of the chuck table 16, the grinding wheel 14a and the chuck table 16 are stopped and the grinding wheel 14a is retracted. Then, after the insertion unit 13 removes the support ring 30 from the annular groove 17, it flips the support ring 30 up and down, and with the upper end face 31 facing upward, the support ring 30 is re-inserted into the annular groove 17.

[0062] like Figure 6 As shown in (c), before internal grinding, while rotating the chuck table 16, a dual-fluid jet ejected from the dual-fluid nozzle 15b is sprayed toward the outside of the chuck 40, the outside of the chuck table 16, and the upper end face 31 of the support ring 30 to clean sludge and other debris generated during grinding of the support ring 30. Thus, for example, when using a cleaning device that presses a hard cleaning stone or the like onto the chuck table 16, the upper end face 31 is higher than the outside of the chuck table 16, potentially causing cleaning residue. In contrast, cleaning with the dual-fluid is independent of the slight height difference between the upper end face 31 and the outside of the chuck table 16; the dual-fluid disperses across the entire surface of the chuck table 16, enabling efficient cleaning.

[0063] [Wafer Grinding]

[0064] The robotic arm 18 transports the wafer 20 with the BG film 21 attached from the film attachment section 11 to the inner surface grinding section 12, such as... Figure 7 As shown in (a), the wafer 20 is placed on the chuck stage 16 with its inner surface 22 facing upward.

[0065] When a negative pressure is supplied between the wafer 20 and the chuck 40, the wafer 20 is held by the chuck 40. At this time, the bump region 24 is supported by the chuck 40, and the outer peripheral region 25 is supported by the upper end face 31, and so on. Figure 7 As shown in (b), the curved region 26 is supported in close contact with the support surface 32. That is, the BG membrane 21 is supported across the entire surface between the support ring 30 and the chuck 40 without any gaps.

[0066] Then, as Figure 7 As shown in (c), while rotating the grinding wheel 15a and the chuck table 16, the grinding wheel 15a is pressed downward, thereby grinding the inner surface 22 of the wafer 20. During grinding of the inner surface of the wafer 20, the BG film 21 is supported across the entire surface without gaps between the support ring 30 and the chuck 40, thus enabling grinding of the wafer 20 without damaging it.

[0067] In the above embodiments, the present invention has been described using a processing apparatus 10 for grinding the inner surface of a wafer 20 as an example, but it can also be applied to apparatuses for grinding wafers 20, etc.

[0068] In addition, the support ring 30 is not limited to a structure that integrates the upper end surface 31 supporting the outer peripheral region 25 and the support surface 32 supporting the bending region 26. The upper end surface 31 and the support surface 32 can also be provided separately.

[0069] Furthermore, various modifications can be made to this invention in addition to the above, as long as they do not depart from the spirit of this invention, and this invention naturally includes the invention after such modifications.

[0070] Explanation of the labels:

[0071] The designation 10 indicates the processing device;

[0072] The number 11 indicates the membrane adhesion section;

[0073] The designation 12 indicates the internal grinding section;

[0074] Label 13 indicates the insertion unit;

[0075] The designation 14 indicates the end face grinding unit;

[0076] The designation 14a indicates a grinding wheel;

[0077] The designation 14b indicates a machining gauge;

[0078] The designation 15 indicates an internal grinding unit;

[0079] The designation 15a indicates a grinding wheel;

[0080] The designation 15b indicates a dual-fluid nozzle (cleaning mechanism);

[0081] The designation 15c indicates a machining gauge;

[0082] The number 16 indicates the chuck worktable;

[0083] The designation 16a indicates an opening;

[0084] The designation 16b indicates a drain hole;

[0085] The designation 16c indicates a threaded hole;

[0086] The number 17 indicates an annular groove;

[0087] The number 18 indicates a robotic arm;

[0088] The designation 20 indicates a wafer;

[0089] The designation 21 indicates a BG membrane;

[0090] The designation 22 indicates the inner surface (of the wafer);

[0091] The designation 23 indicates the outside (of the wafer);

[0092] Label 24 indicates the bump area;

[0093] The number 25 indicates the outer perimeter area;

[0094] Label 26 indicates a curved area;

[0095] The designation 30 indicates a support ring (support component);

[0096] The number 31 indicates the upper surface;

[0097] The designation 32 indicates the support surface;

[0098] The number 33 indicates the lower end face;

[0099] The number 40 indicates a chuck;

[0100] The symbol 50 represents a screw;

[0101] The symbol B represents a convex block;

[0102] The symbol C represents a chip.

Claims

1. A processing apparatus for grinding the inner surface of a wafer, said wafer including a bump region and an outer peripheral region surrounding said bump region, said bump region being obtained by forming bumps on the outer surface of said wafer, wherein, A film is adhered to the aforementioned outer surface, characterized in that the processing apparatus comprises: A chuck that holds the bump areas of the aforementioned wafer; A support member, shaped to correspond to a curved region, has a support surface supporting the curved region and is capable of supporting the outer peripheral region of the wafer, wherein the film bends from the bump region to the outer peripheral region in the curved region; and A chuck worktable that houses the chuck and the support components that are located on the outer periphery of the chuck.

2. The processing apparatus according to claim 1, characterized in that, The aforementioned support component is embedded in the annular groove formed on the outer periphery of the aforementioned chuck.

3. The processing apparatus according to claim 1 or 2, characterized in that, The aforementioned support components and chuck table are made of materials exhibiting the same coefficient of thermal expansion.

4. The processing apparatus according to claim 2, characterized in that, The chuck worktable is provided with a drainage hole that connects the annular groove to an opening formed on the periphery of the chuck worktable.

5. The processing apparatus according to claim 1, characterized in that, It also has a cleaning mechanism that sprays a dual fluid toward the outside of the aforementioned chuck worktable.

6. A processing method for grinding the inner surface of a wafer, the wafer comprising a bump region and an outer peripheral region surrounding the bump region, the bump region being obtained by forming bumps on the outer surface of the wafer, wherein... A film is adhered to the aforementioned outer surface, characterized in that the processing method includes: A process for determining the shape of a curved region in the above-mentioned membrane, wherein the membrane bends from the above-mentioned protrusion region to the above-mentioned peripheral region in the curved region; The process of forming a support surface corresponding to the shape of the aforementioned curved region on the inner periphery of the upper end face of the support component; The process of grinding the outer surface of the chuck that can hold the bump area of ​​the wafer and the outer surface of the chuck table that houses the chuck to be approximately flat. The process of inserting the support member into the annular groove of the chuck worktable formed on the outer periphery of the chuck with the lower end face of the support member facing upward; The process of grinding the lower end face of the above-mentioned support component to a specified height from the outside of the above-mentioned chuck worktable; The process of flipping the aforementioned support components up and down; The process of holding the wafer in a chuck with the aforementioned support surface supporting the aforementioned curved region and the aforementioned upper end surface supporting the aforementioned outer peripheral region.

7. The processing method according to claim 6, characterized in that, In the process of grinding the lower end face of the support component, the grinding is performed while measuring the height of the lower end face of the support component relative to the outside of the chuck worktable.

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