Grinding device

Abstract

To provide a polishing device which resolves a problem of corrosion of the interior of a through hole of a rotary shaft caused by a polishing liquid.SOLUTION: A polishing device 1 includes: a chuck table 3 which holds a workpiece 10; polishing means 4 which polishes the workpiece 10 held by the chuck table 3; and polishing liquid supply means 6 which supplies a polishing liquid S to the polishing means 4. The polishing means 4 includes: a rotary shaft 41 having a through hole 41a extending from an upper end 41b to a lower end 41c; and a polishing pad attachment part 42 which is disposed at the lower end 41c of the rotary shaft 41 and to which the polishing pad 43 is attached. Rust prevention treatment with resin is performed at the inner side of the through hole 41a to prevent corrosion caused by the polishing liquid S which is supplied to the upper end 41b by the polishing liquid supply means 6 and reaches the lower end 41c.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polishing apparatus for polishing a workpiece held on a chuck table.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are formed on the surface and partitioned by a dividing line is ground on the back surface by a grinding apparatus to a predetermined thickness, and then divided into individual device chips by a dicing apparatus or a laser processing apparatus, and used in electrical devices such as mobile phones and personal computers.

[0003] In addition, when the back surface of the wafer is ground by a grinding apparatus, grinding strain remains and the flexural strength of the device chip decreases. Therefore, in order to remove the grinding strain, the back surface of the ground wafer is polished by a polishing apparatus (see, for example, Patent Document 1).

[0004] The above polishing apparatus includes a chuck table for holding a workpiece, polishing means for polishing the workpiece held on the chuck table, and polishing liquid supply means for supplying polishing liquid. The polishing means includes a rotating shaft having a through hole extending from an upper end portion to a lower end portion, and a polishing pad mounting portion disposed at the lower end portion of the rotating shaft for mounting a polishing pad. The polishing liquid supply means is configured to supply polishing liquid from the upper end portion to the lower end portion of the through hole of the rotating shaft, and the wafer can be polished to a desired state.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, the polishing fluid supplied by the polishing fluid supply means installed in the above-mentioned polishing apparatus is, for example, a processing fluid in which free abrasive particles are suspended. If the rotating shaft is made of metal, and the polishing process is continued by supplying the polishing fluid into the through-hole of the rotating shaft, a problem arises in which the inside of the through-hole of the rotating shaft corrodes due to the action of the polishing fluid. In particular, if the polishing fluid has acidic properties, even if the rotating shaft is made of SUS (stainless steel), a problem arises in which corrosion occurs due to the action of the polishing fluid.

[0007] This invention has been made in view of the above facts, and its main technical objective is to provide a polishing device that solves the problem of corrosion inside the through hole of the rotating shaft due to the polishing liquid. [Means for solving the problem]

[0008] To solve the above-mentioned main technical problems, the present invention provides a polishing apparatus comprising a chuck table for holding a workpiece, a polishing means for polishing the workpiece held on the chuck table, and a polishing liquid supply means for supplying a polishing liquid to the polishing means, wherein the polishing means comprises a rotating shaft whose inner wall is formed by through holes through which the polishing liquid passes, from the upper end to the lower end, It comprises a polishing pad mounting portion, which is a plate-shaped member on which a polishing pad is attached to the lower surface and which is attached in surface contact to the lower end of the rotating shaft where the through hole is exposed on the upper surface, The inside of the through hole from the upper end to the lower end Throughout the entire area A polishing device is provided that is treated with a resin to prevent rust, thereby preventing corrosion by the polishing liquid supplied to the upper end by the polishing liquid supply means and reaching the lower end.

[0009] The rust prevention treatment may be a process of inserting and installing a resin pipe into the through hole, or it may be a process of coating the inside of the through hole with resin. [Effects of the Invention]

[0010] The polishing apparatus of the present invention comprises a chuck table for holding a workpiece, a polishing means for polishing the workpiece held on the chuck table, and a polishing liquid supply means for supplying a polishing liquid to the polishing means, wherein the polishing means comprises a rotating shaft whose inner wall is formed by through holes through which the polishing liquid passes from the upper end to the lower end, It comprises a polishing pad mounting portion, which is a plate-shaped member on which a polishing pad is attached to the lower surface and which is attached in surface contact to the lower end of the rotating shaft where the through hole is exposed on the upper surface, The inside of the through hole from the upper end to the lower end Throughout the entire area Since the resin is used for rust prevention, corrosion by the polishing fluid supplied to the upper end by the polishing fluid supply means and reaching the lower end is prevented, thus eliminating the problem of corrosion inside the through hole of the rotating shaft of the polishing means due to the polishing fluid reaching from the upper end to the lower end by the polishing fluid supply means. [Brief explanation of the drawing]

[0011] [Figure 1] This is an overall perspective view of the polishing apparatus of this embodiment. [Figure 2] This is a schematic cross-sectional view of the polishing means to be attached to the polishing apparatus shown in Figure 1. [Figure 3] (a) A cross-sectional view showing an embodiment of the rust prevention treatment applied to the rotating shaft shown in Figure 2, and (b) A cross-sectional view of the rotating shaft that has undergone the rust prevention treatment shown in (a). [Figure 4] (a) A cross-sectional view showing another embodiment of the resin-based rust prevention treatment applied to the rotating shaft shown in Figure 2, and (b) A cross-sectional view of the rotating shaft that has undergone the rust prevention treatment shown in (a). [Figure 5] This is a perspective view of a wafer being polished by the polishing apparatus shown in Figure 1. [Figure 6] Figure 1 is a perspective view showing the polishing process performed by the polishing apparatus described in Figure 1. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of a polishing apparatus configured according to the present invention will be described in detail with reference to the attached drawings.

[0013] Figure 1 shows an overall perspective view of the polishing apparatus 1 of this embodiment. The polishing apparatus 1 comprises at least a chuck table 3 for holding a workpiece wafer 10 (for example, a silicon (Si) wafer), a polishing means 4 for polishing the back surface 10b of the wafer 10 held on the chuck table 3, a lifting means 5 for raising and lowering the polishing means 4 in the Z-axis direction (vertical direction), and a polishing liquid supply means 6 for supplying polishing liquid S to the polishing means 4.

[0014] The chuck table 3 comprises a holding plate 31 having a holding surface 31a for suction holding the wafer 10, and a frame 32 that supports the holding plate 31 and transmits negative pressure to the holding surface 31a. The chuck table 3 is configured to be rotatable by a rotary drive means (not shown) and can be moved to any position in the X-axis direction by an X-axis moving means (not shown) housed inside the apparatus housing 2, for example, an loading / unloading position for loading and unloading the wafer 10 on the front side of the figure, and a polishing position where polishing is performed directly below the polishing means 4.

[0015] The polishing means 4 comprises a rotating shaft 41 rotatably held in a rotating shaft housing 40, a polishing pad mounting portion 42 detachably disposed at the lower end of the rotating shaft 41, a polishing pad 43 mounted on the lower surface of the polishing pad mounting portion 42, an electric motor 44 (see also Figure 2) housed inside the rotating shaft housing 40 to rotate the rotating shaft 41, a support portion 45 for supporting the rotating shaft housing 40, and a Z-axis movable base 46 supported together with the support portion 45 in the vertical wall portion 2a of the device housing 2 so as to be able to move up and down in the Z-axis direction. The rotating shaft 41 is made of stainless steel, for example, the polishing pad mounting portion 42 is made of a hard resin plate, for example, the polishing pad 43 is made of polyurethane and is bonded to the lower surface of the polishing pad mounting portion 42. The lower surface of the polishing pad 43 is grooved to hold and diffuse the polishing liquid S supplied from the polishing liquid supply means 6.

[0016] The lifting means 5 converts the rotational motion of the pulse motor 51 into linear motion via a ball screw 52 rotated by the pulse motor 51 and transmits it to the Z-axis movement base 46, enabling the polishing means 4 to be moved to an arbitrary position in the Z-axis direction (vertical direction). The polishing liquid supply means 6 includes a polishing liquid supply source 61, a communication path 62, and an on-off valve 63 for opening and closing the communication path 62. The communication path 62 is connected to the upper end portion 41b of a through-hole 41a inside the rotating shaft 41 of the polishing means 4. The polishing liquid S supplied from the polishing liquid supply source 61 is, for example, a suspension (slurry) of fine silica powder particles in a solvent. When polishing is performed, it is supplied from the upper end portion 41b of the rotating shaft 41, reaches the lower end portion 41c (also refer to FIG. 2) via the through-hole 41a, and is supplied to the wafer 10 held on the chuck table 3 and the polishing pad 43 for polishing the wafer 10 through openings formed in the polishing pad mounting portion 42 and the polishing pad 43. The polishing apparatus 1 includes control means (not shown), and each of the above-described operating parts is controlled by a control signal instructed from the control means.

[0017] FIG. 2 is a schematic cross-sectional view showing the internal configuration of the rotating shaft housing 40 of the polishing means 4 of the present embodiment. The rotating shaft housing 40 supports the rotating shaft 41 at its center, and the rotating shaft 41 has a disk-shaped thrust plate 41d and a radial bearing portion 41e formed integrally. An air supply port 40a to which high-pressure air is supplied from a high-pressure air supply source (not shown) is provided in the rotating shaft housing 40. The high-pressure air introduced from the air supply port 40a is supplied to a minute gap 41f at a portion where the thrust plate 41d and the radial bearing portion 41e of the rotating shaft 41 are disposed via an air supply path (not shown) formed inside the rotating shaft housing 40, and is discharged from an exhaust port (not shown). Due to the action of the high-pressure air introduced from the air supply port 40a, a high-pressure air layer by the high-pressure air is formed in the minute gap 41f at a portion where the thrust plate 41d and the radial bearing portion 41e of the rotating shaft 41 are disposed, and the rotating shaft 41 is supported in a non-contact state with respect to the rotating shaft housing 40. The minute gap 41f forming the high-pressure air layer is, for example, 5 to 10 μm.

[0018] Here, inside the through-hole 41a of the above-described rotating shaft 41, a rust prevention treatment using resin, which will be described later, is performed. Referring to FIGS. 3 and 4, an embodiment of the rust prevention treatment using resin of the present invention will be described.

[0019] FIG. 3 shows a schematic cross-sectional view of the rotating shaft 41 of the grinding means 4 (for convenience of explanation, a part is omitted). The rotating shaft 41 is formed of, for example, stainless steel. As shown in FIG. 3(a), for the through-hole 41a penetrating vertically in the rotating shaft 41, a resin pipe 70 having the same outer diameter as the inner diameter of the through-hole 41a is prepared. The resin pipe 70 is made of a well-known synthetic resin excellent in chemical resistance, and for example, a resin pipe of polyvinyl chloride is adopted. The resin pipe 70 is inserted into the through-hole 41a in the direction indicated by the arrow R1 and press-fitted, and as shown in FIG. 3(b), it is mounted inside the through-hole 41a. The inserted resin pipe 70 is set to the length from the upper end portion 41b to the lower end portion 41c of the through-hole 41a. In the above-described embodiment, the resin pipe 70 is mounted in the through-hole 41a of the rotating shaft 41 by press-fitting, but if necessary, it may be mounted in the through-hole 41a using an adhesive or the like.

[0020] FIG. 4 shows an embodiment different from the embodiment of the rust prevention treatment shown in FIG. 3 described above. As shown in FIG. 4(a), the resin supply nozzle 81 of the resin supply means 80 for supplying the liquid resin 72 is positioned at the upper end portion 41b of the through-hole 41a of the rotating shaft 41 where no rust prevention treatment has been performed, and the resin 72 is sprayed from the resin supply nozzle 81. While spraying the resin 72 in this way, the resin supply nozzle 81 is moved in the direction indicated by the arrow R2, and as shown in FIG. 4(b), the resin 72 is coated over the entire inner area from the upper end portion 41b to the lower end portion 41c of the through-hole 41a. The resin 72 is a synthetic resin that does not dissolve in water after drying and has chemical resistance.

[0021] The polishing apparatus 1 of the present embodiment has a configuration generally as described above, and its functions and operations will be described below.

[0022] Figure 5 shows a wafer 10 to be processed by the polishing apparatus 1 of this embodiment. The wafer 10 is, for example, a silicon (Si) wafer, in which multiple devices 12 are formed on the surface 10a, partitioned by division lines 14. A protective tape T is attached to the surface 10a of the wafer 10 as shown in the figure. Once the wafer 10 shown in Figure 5 is prepared, as shown in Figure 1, it is placed on the chuck table 3 positioned at the loading / unloading position with the back surface 10b facing upwards and the side with the protective tape T attached facing downwards, and then held in place by suction. In this embodiment, the wafer 10 to be processed has its back surface 10b ground by a grinding apparatus (not shown) to the desired thickness before being transported to the polishing apparatus shown in Figure 1.

[0023] Next, the X-axis moving means described above is activated to position the chuck table 3 at the polishing position directly below the polishing means 4. Then, as shown in Figure 6, the rotational drive means (not shown) is activated to rotate the chuck table 3 at a predetermined rotational speed in the direction indicated by arrow R3, and the rotation axis 41 of the polishing means 4 at a predetermined rotational speed in the direction indicated by arrow R4. Next, the lifting means 5 described above is activated to lower the polishing means 4 in the direction indicated by arrow R5, bringing the polishing pad 43 into contact with the back surface 10b of the wafer 10. This closes the polishing pad mounting portion 42 and the opening of the polishing pad 43, which communicate with the through hole 41a of the rotation axis 41, with the back surface 10b of the wafer 10. At the same time, the polishing fluid supply means 6 described above is activated to supply the polishing fluid S to the polishing pad 43 and the back surface 10b of the wafer 10 via the through hole 41a of the rotation axis 41, which has been treated with rust prevention. Then, the polishing means 4 is fed at a predetermined speed (for example, 0.1 μm / second), and the entire back surface 10b of the wafer 10 is polished by the polishing liquid S diffused through grooves (not shown) formed on the lower surface side of the polishing pad 43 until it reaches a predetermined state.

[0024] As explained based on Figures 3 and 4 above, the inside of the through-hole 41a of the rotating shaft 41 of the polishing means 4 is treated with a resin to prevent rust. As a result, even if the polishing fluid S is repeatedly supplied and discharged from the upper end 41b to the lower end 41c of the through-hole 41a of the rotating shaft 41 by the polishing fluid supply means 6 as the polishing process is carried out, the problem of corrosion on the inside of the through-hole 41a is eliminated. [Explanation of symbols]

[0025] 1: Polishing device 2: Device housing 2a: Vertical wall 3: Chuck Table 31: Retaining plate 31a: Holding surface 32:Frame body 4: Polishing means 40: Rotary shaft housing 40a: Air supply port 41: Rotation axis 41a: Through hole 41b: Upper end 41c: Bottom end 42: Polishing pad mounting section 43: Polishing pad 44: Electric motor 45: Support part 46:Z-axis moving base 5: Lifting and lowering means 51: Pulse motor 52: Ball screw 6: Polishing liquid supply means 61: Polishing liquid supply source 62: Communication path 63: Shut-off valve 10: Wafer 12: Devices 14: Planned division line S: Polishing liquid

Claims

1. A polishing apparatus comprising a chuck table for holding a workpiece, a polishing means for polishing the workpiece held on the chuck table, and a polishing liquid supply means for supplying a polishing liquid to the polishing means, The polishing means comprises a rotating shaft whose inner wall is formed by through holes through which the polishing liquid passes from the upper end to the lower end, and a polishing pad mounting portion which is a plate-shaped member on which a polishing pad is attached to the lower surface and which is attached in surface contact with the lower end of the rotating shaft where the through holes are exposed on the upper surface. A polishing device in which the entire inner surface of the through hole, from its upper end to its lower end, is treated with a resin to prevent rust, thereby preventing corrosion by the polishing liquid supplied to the upper end by the polishing liquid supply means and reaching the lower end.

2. The polishing apparatus according to claim 1, wherein the rust prevention treatment is a process of inserting and attaching a resin pipe into the through hole.

3. The polishing apparatus according to claim 1, wherein the rust prevention treatment is a treatment in which resin is applied to the inside of the through hole.

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