TWI725265B - Polishing apparatus and pressing pad for pressing polishing tool - Google Patents

Abstract

The present invention provides a polishing device, which can keep the width of the polishing tool in contact with the peripheral part when the polishing tool is inclined to the substrate and the peripheral part of the substrate is polished by the polishing tool. The polishing apparatus includes a substrate holding portion 3 that holds and rotates the substrate W, and a pressing pad 50 that presses the polishing tool 23 on the peripheral edge of the substrate W held by the substrate holding portion 3. The pressing pad 50 has an elastic portion 55 having a pressing surface 55a that presses the peripheral edge portion of the substrate W via the abrasive tool 23; and a supporting member 56 supporting the elastic portion 55; an elastic portion 55 is formed on the front surface 56a of the supporting member 56 to enter之槽57。 The recess 57.

Description

Grinding device, and pressing pad of pressing grinding tool

The present invention relates to a polishing device for polishing substrates such as wafers, and more particularly to a polishing device for polishing the periphery of the substrate by using a polishing tool such as a polishing belt. Furthermore, the present invention relates to a pressing pad for pressing the abrasive tool against the peripheral edge of the substrate.

In the manufacture of semiconductor devices, from the viewpoint of improving the yield rate, the management of the surface condition of the peripheral portion of the substrate has attracted attention in recent years. In the manufacturing process of semiconductor devices, various materials are deposited on silicon wafers to form a multilayer structure. Therefore, an unnecessary film and surface roughness are formed on the periphery of the substrate. In recent years, a method of transporting the substrate by holding only the peripheral portion of the substrate by a support arm has been generally adopted. Under this background, the unnecessary film remaining on the peripheral portion is gradually peeled off through various processes and adheres to the element formed on the substrate, resulting in a decrease in yield. Therefore, in order to remove the unnecessary film formed on the peripheral edge of the substrate, a polishing device is used to polish the peripheral edge of the substrate. Here, the present specification defines the peripheral edge portion of the substrate as a region including the groove portion located at the outermost periphery of the substrate, the top edge portion and the bottom edge portion located inside the groove portion in the radial direction.

Figures 23(a) and 23(b) are enlarged cross-sectional views of the periphery of a wafer showing an example of a substrate. In more detail, FIG. 23(a) is a cross-sectional view of a so-called straight-edge wafer, and FIG. 23(b) is a cross-sectional view of a so-called round wafer. In the wafer W in Figure 23(a), the groove is composed of an upper inclined portion (upper groove) P, a lower inclined portion (lower groove) Q, and a side portion (apex portion) The outermost peripheral surface of the wafer W composed of R (indicated by the symbol B). In the wafer W in Figure 23(b), the groove is It is a portion (indicated by symbol B) that constitutes the outermost peripheral surface of wafer W and has a curved cross-section. The top edge portion is a flat portion E1 located radially inner than the groove portion B. The bottom edge portion is located on the opposite side to the top edge portion, and is a flat portion E2 located radially inner than the groove portion. The top edge portion also includes the area where the device is formed.

An apparatus for removing the film formed on the peripheral portion of the wafer W is conventionally known as a polishing apparatus using a polishing tool such as a polishing tape (for example, refer to Patent Document 1). This type of polishing apparatus includes: a substrate holding portion that holds and rotates the wafer W; and a polishing head for contacting the polishing tape (abrasive tool) against the peripheral edge of the wafer W; the polishing head has the ability to press the polishing tape against the wafer W. Pressing pad at the periphery of circle W. The polishing surface of the polishing tape is pressed against the peripheral edge of the wafer W by a pressing pad arranged on the back side of the polishing tape to polish the peripheral edge. The abrasive tool can also use a belt-shaped abrasive cloth to replace the abrasive belt.

Figure 24 is a perspective view showing an example of a pressing pad in the past. As shown in FIG. 24, the pressing pad 150 includes: an elastic member 155 having a rectangular pressing surface 155a; and a pad body 154 to which the elastic member 155 is fixed. The elastic member 155 is fixed to the pad body 154 in a state where the entire back surface opposite to the pressing surface 155a is in contact with the pad body 154. The pressing pad 150 is arranged on the back side of the polishing tape, and the front surface (polishing surface) of the polishing tape is pressed against the groove B of the wafer W by the pressing surface 155a of the elastic member 155. The elastic member 155 of the pressing pad 150 is formed of materials such as rubber or sponge. For example, urethane rubber, silicon sponge, etc. having a hardness suitable for substrate polishing (for example, 20-40 degrees) is selected as the material of the elastic member 155.

FIG. 25 is a schematic diagram showing a state in which the bevel portion B of the wafer W is polished by the polishing head 130 having the pressing pad 150 shown in FIG. 24. As shown in FIG. 25, the polishing head 130 has: a pressing pad 150 that presses the polishing tape 123 on the peripheral edge of the wafer W; and an air cylinder (driving mechanism) 152 that moves the pressing pad 150 toward the peripheral edge of the wafer W ; And a belt feeding mechanism 142 that feeds the abrasive belt 123 in a designated direction. By controlling the air pressure supplied to the air cylinder 152, the force of pressing the polishing belt 123 on the wafer W is adjusted. During the polishing of the groove B of the wafer W, the polishing head 130 (that is, the pressing pad 150) uses a tilt mechanism (without (Illustration) The wafer W is tilted. By tilting the polishing head 130 with respect to the wafer W, and the pressing surface 155a of the elastic member 155 of the pressing pad 150 presses the polishing tape 123 on the groove B of the wafer W, the entire groove can be polished by the polishing tape 123 B.

[Prior Technical Literature] (Patent Document)

[Patent Document 1] Japanese Patent No. 5254575

When the polishing head 130 (that is, the pressing pad 150) is inclined to the wafer W in order to polish the entire groove B, the width of the polishing tape 123 in contact with the groove B of the wafer W changes. Figure 26 shows that when the pressing surface 155a of the elastic member 155 of the pressing pad 150 shown in Figure 24 is perpendicular to the flat surface of the wafer W, it is in contact with the groove B of the wafer W via the polishing belt 123 A schematic diagram of the width of the pressing surface 155a of the elastic member 155. Figure 27 shows that when the pressing surface 155a of the elastic member 155 of the pressing pad 150 shown in Figure 24 is inclined to the flat surface of the wafer W, it contacts the groove B of the wafer W via the polishing belt 123 A schematic diagram of the width of the pressing surface 155a of the elastic member 155. Figure 26 and Figure 27 do not describe the polishing tape 123 for the sake of simplicity. However, the width of the polishing tape 123 contacting the groove portion B of the wafer W during polishing corresponds to the width of the polishing tape 123 through the polishing tape 123 and the wafer. The width of the pressing surface 155a of the elastic member 155 with which the groove portion B of W contacts.

As shown in Figures 26 and 27, when the pressing surface 155a is perpendicular to the flat surface of the wafer W, the width Wa of the polishing tape contacting the groove B of the wafer W is larger than that of the pressing surface 155a. Flat W When the surface is inclined, the width Wb of the polishing tape in contact with the groove B of the wafer W is small. As the inclination angle of the pressing surface 155a with respect to the flat surface of the wafer W increases, the width of the polishing tape in contact with the groove B of the wafer W increases.

The twenty-eighth figure is a photograph showing the polishing marks attached to the polishing tape 123 when the polishing tape 123 is pressed against the groove portion B of the wafer W with the conventional pressing pad 150 to polish the groove portion B. The twenty-eighth figure shows a plurality of polishing marks when the bevel portion B of the wafer W is polished by changing the inclination angle θ of the pressing surface 155a to the flat surface of the wafer W every 10°. Figures 29 (a), (b), (c) are schematic diagrams showing the inclination angle θ of the pressing surface 155a to the flat surface of the wafer W. In the twenty-ninth (a), (b), and (c) figures, the abrasive belt 123 shows a longitudinal section along the center of the pressing surface 155a. The inclination angle θ is 0° when the pressing surface 155a of the elastic member 155 of the pressing pad 150 is perpendicular to the flat surface of the wafer W, as shown in FIG. 29(a). The inclination angle θ is as shown in Fig. 29(b), and is a positive value when the pressing surface 155a is inclined in the direction in which the upper end of the pressing surface 155a is close to the flat surface of the wafer W, as shown in Fig. 29(c) As shown, it is a negative value when the pressing surface 155a is inclined in a direction away from the flat surface of the wafer W at the upper end of the pressing surface 155a.

From the photo shown in Figure 28, it can be understood that as the absolute value of the inclination angle θ becomes larger, the length of the polishing trace becomes larger. For example, the length La of the polishing trace when the inclination angle θ is 0° is smaller than the length Lb of the polishing trace when the inclination angle θ is 70°. The difference in the length of the polishing trace is equivalent to the difference in the width of the polishing tape 123 in contact with the groove B of the wafer W. The width of the polishing tape 123 in contact with the groove portion B of the wafer W becomes smaller, and the amount of the polishing tape 123 that contributes to the polishing of the groove portion B is reduced. As a result, the polishing rate when the absolute value of the inclination angle θ of the pressing surface 155a is small is lower than the polishing rate when the absolute value of the inclination angle θ of the pressing surface 155a is large.

Furthermore, it can be understood from the photo shown in Fig. 28 that when the absolute value of the inclination angle θ is small, the color brightness of the central area of the polishing mark is higher than the color brightness of the outer area of the polishing mark. The brightness difference of the polishing marks is shown in Fig. 30, which shows the pressing in the center of the contact area between the polishing tape 123 and the groove B of the wafer W The force Fa is greater than the pressing force Fb outside the contact area between the polishing tape 123 and the groove B of the wafer W. At this time, clogging of the polishing tape 123 easily occurs in the center of the contact area of the polishing tape, and the polishing rate decreases.

Therefore, an object of the present invention is to provide a polishing device that can incline the polishing tool to the substrate and maintain a constant width of the polishing tool contacting the peripheral edge when the polishing tool is used to polish the peripheral edge of the substrate. Furthermore, the object of the present invention is to provide a pressing pad for pressing the polishing tool used in the polishing device.

One aspect of the present invention provides a polishing apparatus, which is characterized by comprising: a substrate holding portion that holds and rotates the substrate; and a pressing pad that presses the polishing tool to the peripheral edge portion of the substrate held by the substrate holding portion The pressing pad has: an elastic member, which has a pressing surface that presses the peripheral portion of the substrate via the abrasive tool; and a support member, which supports the elastic member; and the elastic member is formed on the front surface of the support member to allow entry The concave part.

In one embodiment, the pressing pad further includes a fixing unit that fixes both ends of the elastic member to the supporting member.

One embodiment is that the bottom surface of the aforementioned recess is curved.

In one embodiment, a thin plate is attached to the back surface of the elastic member on the opposite side of the pressing surface.

In one embodiment, the aforementioned abrasive tool is composed of an abrasive belt.

In one embodiment, the pressing surface of the elastic member is formed with a groove extending toward the back surface opposite to the pressing surface, and the elastic member has a block divided by the groove.

In one embodiment, the abrasive tool is a grindstone installed in front of the block.

One aspect of the present invention provides a pressing pad that presses an abrasive tool for polishing the peripheral edge of a substrate against the peripheral edge, and is characterized by having: an elastic member that is pressed by the abrasive The pressing surface of the peripheral portion of the substrate; and a supporting member that supports the elastic member; and a recess into which the elastic member can enter is formed on the front surface of the supporting member.

In one embodiment, the pressing pad further includes a fixing unit that fixes both ends of the elastic member to the supporting member.

One embodiment is that the bottom surface of the aforementioned recess is curved.

In one embodiment, a thin plate is attached to the back surface of the elastic member on the opposite side of the pressing surface.

In one embodiment, the aforementioned abrasive tool is composed of an abrasive belt.

In one embodiment, the pressing surface of the elastic member is formed with a groove extending toward the back surface opposite to the pressing surface, and the elastic member has a block divided by the groove.

In one embodiment, a grinding stone used as the abrasive tool is installed on the front surface of the block body.

In the present invention, when the abrasive tool is pressed on the peripheral edge of the substrate on which the pressing pad rotates, the elastic member of the pressing pad enters the recess of the supporting member and deforms into the shape of the elastic member along the peripheral edge of the substrate. As a result, when the abrasive tool is inclined to the substrate and the peripheral edge of the substrate is polished with the abrasive tool, the width of the abrasive tool in contact with the substrate can be maintained constant.

1A, 1B, 1C, 1D: Grinding head assembly (grinding part)

2A, 2B, 2C, 2D: abrasive belt supply mechanism

3: Rotation holding mechanism (substrate holding part)

4: Keep the stage

4a: groove

5: Hollow shaft

6: Ball spline bearing

7: Connecting road

8: Rotary joint

9: Vacuum line

10: Nitrogen supply line

12: Shell

14: shell

15: Air cylinder

18: Radial bearing

19: bellows

20: Partition wall

20a: opening

20b: Transport port

20c: opening

21: Grinding room

23: Grinding belt

24: supply reel

25: Recycling reel

27: Coupler

30: Grinding head

31, 32, 33, 34: guide roller

36: Upper side supply nozzle

37: Lower side supply nozzle

38: Wash the nozzle

40: Ventilation window

41: Pressing mechanism

42: With feeding mechanism

42a: With feed roller

42b: With holding roller

43, 44, 45, 46, 47, 48, 49: guide roller

50: press pad

52: Air cylinder

54: Pad body

54a, 54b: protrusions

54c: Through hole

55: Elastic part (silicon sponge)

55a: pressing surface

55b: back

55c, 55d: both ends

55e, 55f: fixed protrusion

56: Supporting member

56a: front

56b: back

56c: Through hole

57: recess

57a: bottom surface

57b: one side

57c: the other side

58: One end

58a: front

59: The other end

59a: front

60: support arm

61: mobile station

62: guide block

63: Orbit

65: bottom plate

66: Link plate

67: Linear actuator

68: Connector

70: fixed unit

71: fixed block

71a: Step difference

71b: Screw hole

72: Screw

73, 74: thin plate

78: Groove

80: Cube

82: Grindstone

123: Grinding belt

130: Grinding head

142: With feeding mechanism

150: press pad

154: Pad body

155: Elastic member

155a: pressing surface

B: Groove

M1~M4: Motor

Cr: central axis

Ct: Rotation axis

E1, E2: flat part

P: Upper slope

Q: Lower side slope

R: side

W: Wafer

W1, W2: width

The first figure is a top view of a polishing device according to an embodiment.

The second figure is a longitudinal cross-sectional view of the polishing device shown in the first figure.

The third image is an enlarged view of the grinding head.

The fourth figure is a perspective view schematically showing the pressing pad of one embodiment.

Figure 5 is a schematic front view of the pressing pad shown in Figure 4.

The sixth figure is a schematic side view of the pressing pad shown in the fourth figure.

The seventh figure is the A-A line cross-sectional view of the fifth figure.

Figure 8 (a) is a schematic perspective view of the silicon sponge shown in Figure 4, and Figure 8 (b) is a schematic front view of the silicon sponge shown in Figure 8 (a).

Figure 9(a) is a front view of the support member shown in Figure 4, and Figure 9(b) is a cross-sectional view taken along line B-B in Figure 9(a).

The tenth figure is the C-C line cross-sectional view of the seventh figure.

The eleventh figure shows the situation of the polishing head grinding the groove part of the wafer.

The twelfth figure is a diagram showing how the polishing head grinds the top edge of the wafer.

Figure 13 is a diagram showing how the polishing head grinds the bottom edge of the wafer.

Figure 14 is a schematic diagram showing the state where the elastic member enters the recess of the support member.

Figure 15(a) is a schematic diagram showing the elastic member deformed by being pushed back by the groove of the wafer when the pressing surface of the elastic member of the pressing pad is perpendicular to the flat surface of the wafer, 15(b) The figure is a schematic diagram showing the pressing force in the contact area between the polishing tape pressed by the pressing pad shown in Fig. 15(a) and the groove portion of the wafer.

Figure 16(a) is a schematic diagram showing the elastic member deformed by being pushed back by the groove of the wafer when the pressing surface of the elastic member of the pressing pad is inclined to the flat surface of the wafer, 16(b) The figure is a schematic diagram showing the pressing force in the contact area between the polishing tape pressed by the pressing pad shown in Fig. 16(a) and the groove portion of the wafer.

The seventeenth figure is a photograph showing the polishing marks attached to the polishing tape when the polishing tape is pressed on the groove of the wafer with a pressing pad to polish the groove.

Figure 18 is a graph showing the results of other experiments.

Figure 19 is a cross-sectional view showing another embodiment of the pressing pad.

Figure 20 is a cross-sectional view of a pressing pad according to another embodiment.

Figure 21 is a cross-sectional view of a pressing pad according to another embodiment.

Figure 22 is a cross-sectional view of a pressing pad according to another embodiment.

Figure 23 (a) and Figure 23 (b) are enlarged cross-sectional views showing the peripheral edge of the substrate.

Figure 24 is a perspective view showing an example of a pressing pad in the past.

FIG. 25 is a schematic diagram showing a state in which the bevel portion of the wafer is polished by the polishing head having the pressing pad shown in FIG. 24.

The twenty-sixth figure shows the width of the pressing surface of the elastic member contacting the groove of the wafer through the polishing tape when the pressing surface of the elastic member of the pressing pad shown in figure 24 is perpendicular to the flat surface of the wafer Pattern diagram.

The twenty-seventh figure shows the width of the pressing surface of the elastic member contacting the groove of the wafer via the polishing tape when the pressing surface of the elastic member of the pressing pad shown in figure 24 is inclined. Pattern diagram.

The twenty-eighth figure is a photograph showing the polishing marks attached to the polishing tape when the polishing tape is pressed against the groove of the wafer with the pressing pad shown in Figure twenty-four to polish the groove.

The twenty-ninth (a), (b), (c) diagrams are schematic diagrams showing the inclination angle of the pressing surface on the flat surface of the wafer.

Figure 30 is a schematic diagram showing the pressing force in the contact area between the polishing tape pressed by the pressing pad shown in Figure 24 and the groove portion of the wafer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The first figure is a plan view showing the polishing device of one embodiment, and the second figure is a longitudinal sectional view of the polishing device shown in the first figure. As shown in the first and second figures, the polishing apparatus has a rotation holding mechanism (substrate holding portion) 3 that horizontally holds and rotates a wafer W, which is an example of a substrate, at its center. The first figure shows the state in which the rotation holding mechanism 3 holds the wafer W. The rotation holding mechanism 3 includes: a disk-shaped holding stage 4 that holds the back surface of the wafer W by vacuum suction; a hollow shaft 5 connected to the center of the holding stage 4; and a motor M1 that rotates the hollow shaft 5 . The wafer W is loaded on the holding stage 4 by the arm of the transport mechanism (not shown) in such a way that the center of the wafer W is aligned with the axis of the hollow shaft 5.

The hollow shaft 5 is supported movably up and down by a ball spline bearing (linear motion bearing) 6. A groove 4 a is formed on the upper surface of the holding stage 4, and the groove 4 a communicates with a communication path 7 extending through the hollow shaft 5. In one embodiment, a thin plate formed with a groove 4 a communicating with a communication path 7 extending through a hollow shaft 5 may be attached to the upper surface of the holding stage 4. The groove 4a is formed by punching a thin plate, for example. The communication path 7 is connected to the vacuum line 9 via a rotary joint 8 installed at the lower end of the hollow shaft 5. The communication path 7 is also connected to a nitrogen gas supply line 10 for detaching the processed wafer W from the holding stage 4. By switching the vacuum line 9 and the nitrogen supply line 10, the wafer W can be vacuum sucked on the holding stage 4 or detached.

The hollow shaft 5 is rotated by the motor M1 via a pulley p1 connected to the hollow shaft 5, a pulley p2 mounted on the rotating shaft of the motor M1, and a belt b1 hung on these pulleys p1, p2. The rotating shaft of the motor M1 extends parallel to the hollow shaft 5. With this configuration, the wafer W held on the upper surface of the holding stage 4 is rotated by the motor M1.

The ball spline bearing 6 is a bearing that allows the hollow shaft 5 to move freely in its longitudinal direction. The ball spline bearing 6 is fixed to the cylindrical housing 12. Therefore, in this embodiment, the hollow shaft 5 is configured to linearly move up and down the housing 12, and the hollow shaft 5 and the housing 12 rotate integrally. The hollow shaft 5 is connected to an air cylinder (lifting mechanism) 15, and the hollow shaft 5 and the holding stage 4 can be raised and lowered by the air cylinder 15.

A radial bearing 18 is interposed between the housing 12 and a cylindrical housing 14 concentrically arranged on the outside thereof, and the housing 12 is rotatably supported by the bearing 18. With such a configuration, the rotation holding mechanism 3 can rotate the wafer W around the central axis Cr, and raise and lower the wafer W along the central axis Cr.

As shown in the first figure, four polishing head assemblies (polishing parts) 1A, 1B, 1C, and 1D are arranged around the wafer W held by the rotation holding mechanism 3. Abrasive tape supply mechanisms 2A, 2B, 2C, and 2D are provided on the radially outer sides of the polishing head assemblies 1A, 1B, 1C, and 1D, respectively. The polishing head assembly 1A, 1B, 1C, 1D and the polishing tape supply mechanism 2A, 2B, 2C, 2D are separated by a partition wall 20. The internal space of the partition wall 20 constitutes a polishing chamber 21, and the four polishing head assemblies 1A, 1B, 1C, 1D and the holding stage 4 are arranged in the polishing chamber 21. In addition, the polishing tape supply mechanisms 2A, 2B, 2C, and 2D are arranged outside the partition wall 20 (that is, outside the polishing chamber 21). The polishing head assemblies 1A, 1B, 1C, and 1D have the same configuration as each other, and the polishing tape supply mechanisms 2A, 2B, 2C, and 2D have the same configuration as each other. Hereinafter, the polishing head assembly 1A and the polishing tape supply mechanism 2A will be described.

The polishing tape supply mechanism 2A includes: a supply spool 24 that supplies a polishing tape 23 as an example of a polishing tool to the polishing head assembly 1A; and a recovery spool 25 that collects the polishing tape 23 used for polishing the wafer W. The supply reel 24 is arranged above the recovery reel 25. The supply reel 24 and the recovery reel 25 are respectively connected to the motor M2 via a coupler 27 (the first figure only shows the coupler 27 and the motor M2 connected to the supply reel 24). Each motor M2 applies a certain torsion force in a designated rotation direction, and can apply a designated tension to the polishing belt 23.

The grinding belt 23 is a long belt-shaped grinding tool, and one surface thereof constitutes a grinding surface. The polishing belt 23 has: a substrate tape composed of a PET board or the like; and a polishing layer formed on the substrate tape. The polishing layer is composed of an adhesive (for example, resin) covering one surface of the substrate tape and abrasive grains held in the adhesive, and the surface of the polishing layer constitutes a polishing surface. The abrasive tool can also use a belt-shaped abrasive cloth instead of the abrasive belt 23.

The polishing tape 23 is provided in the polishing tape supply mechanism 2A in a state of being wound around the supply reel 24. The side surface of the abrasive belt 23 is supported by a reel plate to avoid winding disorder. One end of the polishing belt 23 is installed on the recycling drum 25, and the polishing belt 23 can be recycled by winding the polishing belt 23 supplied to the polishing head assembly 1A by the recycling drum 25. The polishing head assembly 1A includes a polishing head 30 for making the polishing tape 23 supplied from the polishing tape supply mechanism 2A abut against the peripheral edge of the wafer W. The polishing tape 23 is supplied to the polishing head 30 such that the polishing surface (front surface) of the polishing tape 23 faces the wafer W.

The polishing tape supply mechanism 2A has a plurality of guide rollers 31, 32, 33, 34, and the polishing tape 23 supplied to the polishing head assembly 1A and recovered from the polishing head assembly 1A uses the guide rollers 31, 32, 33, 34 guide. The polishing tape 23 is supplied from the supply drum 24 to the polishing head 30 through the opening 20a provided in the partition wall 20, and the used polishing tape 23 is recovered by the recovery drum 25 through the opening 20a.

As shown in the second figure, an upper supply nozzle 36 is arranged above the wafer W, and the polishing liquid is supplied toward the center of the upper surface of the wafer W held by the rotation holding mechanism 3. In addition, it is provided with a supply nozzle 37 that supplies the polishing liquid toward the back surface of the wafer W and the boundary portion between the rotation holding mechanism 3 and the holding stage 4 (the outer peripheral portion of the holding stage 4). Pure water is generally used for the polishing liquid, but ammonia can also be used when silica is used as the abrasive grains of the polishing belt 23. Furthermore, the polishing device is equipped with a cleaning nozzle 38 that cleans the polishing head 30 after polishing. After the polishing process, the wafer W is lifted by the rotation holding mechanism 3 and then sprayed with washing water toward the polishing head 30 to clean and polish. Polishing head 30 after treatment.

When the hollow shaft 5 lifts and lowers the housing 12, in order to isolate the ball spline bearing 6 and the radial bearing 18 from the grinding chamber 21, as shown in the second figure, the hollow shaft 5 and the upper end of the housing 12 can be telescoped up and down. The bellows 19 is connected. The second figure shows the state of the hollow shaft 5 descending, and shows the holding stage 4 in the grinding position. After the polishing process, the air cylinder 15 raises the wafer W together with the holding stage 4 and the hollow shaft 5 to the transfer position, and releases the wafer W from the holding stage 4 at the transfer position.

The partition wall 20 is provided with a transfer port 20 b for transferring the wafer W into or out of the polishing chamber 21. The conveyance port 20b forms a gap extending horizontally. Therefore, the wafer W held by the transport mechanism remains horizontal and can pass through the polishing chamber 21 through the transport port 20b. An opening 20c and a ventilation window 40 are provided on the upper surface of the partition wall 20, and an exhaust port (not shown) is provided on the lower surface. During the polishing process, the conveyance port 20b is closed with a shutter (not shown). Therefore, by exhausting from the exhaust port by a fan mechanism (not shown), a downflow of clean air can be formed in the polishing chamber 21. Since the polishing process is performed in this state, it is possible to prevent the polishing liquid from scattering upward, to keep the upper space of the polishing chamber 21 clean and to perform the polishing process.

As shown in the first figure, the polishing head 30 is fixed to one end of the support arm 60, and the support arm 60 is configured to rotate freely around a rotation axis Ct parallel to the tangential direction of the wafer W. The other end of the arm 60 is connected to the motor M4 via the pulleys p3 and p4 and the belt b2. By rotating the motor M4 clockwise and counterclockwise by a specified angle, the arm 60 rotates by a specified angle around the axis Ct. In this embodiment, the motor M4, the arm 60, the pulleys p3, p4, and the belt b2 constitute a tilt mechanism for tilting the polishing head 30 with respect to the surface of the wafer W.

The tilt mechanism is mounted on the mobile table 61. The moving table 61 is movably connected to the bottom plate 65 via the guide block 62 and the rail 63. The rail 63 linearly extends along the radial direction of the wafer W held by the rotation holding mechanism 3, and the moving table 61 can move linearly along the radial direction of the wafer W. A connecting plate 66 penetrating the bottom plate 65 is installed in the moving table 61, and the linear actuator 67 is connected to the connecting plate 66 via a joint 68. The linear actuator 67 is directly or indirectly fixed to the bottom plate 65.

The linear actuator 67 may be a combination of an air cylinder, a positioning motor, and a ball screw. The linear actuator 67, the rail 63, and the guide block 62 constitute a moving mechanism for linearly moving the polishing head 30 in the radial direction of the wafer W. That is, the moving mechanism operates to move the polishing head 30 closer to or away from the wafer W along the rail 63. In addition, the polishing tape supply mechanism 2A is fixed to the bottom plate 65.

The third figure is an enlarged view of the polishing head 30. As shown in the third figure, the polishing head 30 includes a pressing mechanism 41 that presses the polishing surface of the polishing tape 23 against the wafer W with a predetermined force. In addition, the polishing head 30 includes a tape feeding mechanism 42 that feeds the polishing tape 23 from the supply reel 24 to the recovery reel 25. The polishing head 30 has a plurality of guide rollers 43, 44, 45, 46, 47, 48, 49, and these guide rollers guide the polishing belt 23 so that the polishing belt 23 travels in a direction perpendicular to the tangential direction of the wafer W.

The tape feeding mechanism 42 provided in the polishing head 30 includes a tape feeding roller 42a, a tape holding roller 42b, and a motor M3 that rotates the tape feeding roller 42a. The motor M3 is arranged on the side surface of the polishing head 30, and a belt feed roller 42a is installed on the rotating shaft of the motor M3. The tape holding roller 42b is arranged adjacent to the tape feeding roller 42a. The tape holding roller 42b is configured to be supported by an unillustrated mechanism to generate force in the direction indicated by the arrow NF in the third figure (the direction toward the tape feed roller 42a), and can press the tape feed roller 42a.

When the motor M3 rotates in the direction of the arrow shown in the third figure, the tape feed roller 42a rotates, and the polishing tape 23 can be fed from the supply spool 24 to the recovery spool 25 via the polishing head 30. The belt holding roller 42b is configured to be rotatable around its own axis, and to rotate with the feeding of the abrasive belt 23.

The pressing mechanism 41 includes a pressing pad 50 arranged on the back side of the polishing belt 23 and an air cylinder (driving mechanism) 52 that moves the pressing pad 50 toward the peripheral edge of the wafer W. The air cylinder 52 is a so-called single rod cylinder. By controlling the air pressure supplied to the air cylinder 52, the force of pressing the polishing belt 23 against the wafer W is adjusted. The tilt mechanism, pressing mechanism 41, tape feeding mechanism 42, and the moving mechanism for moving each polishing head assembly 1A, 1B, 1C, and 1D of the four polishing head assemblies 1A, 1B, 1C, and 1D arranged around the wafer W can operate independently.

The fourth figure is a perspective view schematically showing the pressing pad 50 of one embodiment, the fifth figure is a schematic front view of the pressing pad 50 shown in the fourth figure, and the sixth figure is a schematic side view of the pressing pad 50 shown in the fourth figure. view.

As shown in the fourth to sixth figures, the pressing pad 50 includes: an elastic member 55 having a flat pressing surface 55a that directly presses the polishing tape 23 on the peripheral edge of the wafer W; and a plate-shaped supporting elastic member 55 Support member 56. The detailed structure of the elastic member 55 and the support member 56 is mentioned later. The pressing pad 50 of this embodiment further has a pad body 54, and the supporting member 56 is sandwiched between the elastic member 55 and the pad body 54.

The elastic member 55 is formed of a material such as sponge or rubber. For example, a silicon sponge having a hardness suitable for polishing the wafer W (for example, 20-40 degrees) is selected as the material of the elastic member 55. The elastic member 55 may also be formed of rubber (for example, urethane rubber) having a hardness (for example, 20-40 degrees) suitable for polishing the wafer W. The supporting member 56 is formed of a material harder than the elastic member 55. In the embodiment described below, the elastic member 55 is formed of a silicon sponge, and the elastic member 55 is referred to as a silicon sponge 55.

The pressing surface 55a of the silicon sponge 55 that directly presses the back of the polishing tape 23 (that is, the surface opposite to the polishing surface) is rectangular, and the width of the pressing surface 55a (the dimension along the circumferential direction of the wafer W) D1 is higher than the height ( The dimension D2 along the direction perpendicular to the surface of the wafer W is large.

The pressing pad 50 of this embodiment has two protrusions 54 a and 54 b formed on the front surface of the pad main body 54. These protrusions 54a and 54b have a shape like a rail and are arranged side by side. The protrusions 54a and 54b are curved along the circumferential direction of the wafer W. More specifically, the protrusions 54a and 54b have a circular arc shape having substantially the same curvature as the curvature of the wafer W.

The two protrusions 54a, 54b are arranged symmetrically to the rotation axis Ct (refer to the first figure), and as shown in the fifth figure, when viewed from the front surface of the pressing pad 50, the protrusions 54a, 54b are bent inward toward the rotation axis Ct . The polishing head 30 is installed in such a manner that the center line between the front ends of the protrusions 54a and 54b (that is, the rotation axis Ct) coincides with the center of the wafer W in the thickness direction. The protrusions 54a and 54b are arranged so as to be closer to the wafer W than the guide rollers 46 and 47 (refer to the third figure) arranged on the front surface of the polishing head 30, and the polishing tape 23 is supported from the back by the protrusions 54a and 54b. The pad body 54 including the protrusions 54a and 54b is formed of resin such as PEEK (polyether ether ketone).

As shown in the fourth and fifth figures, the silicon sponge 55 is arranged between the two protrusions 54a and 54b. The height of the silicon sponge 55 is slightly lower than the height of the protrusions 54a and 54b. While the polishing head 30 is maintained horizontally, when the pressing pad 50 is moved toward the wafer W by the air cylinder 52, the silicon sponge 55 presses the polishing tape 23 against the groove B of the wafer W from the back side.

The seventh figure is the AA line cross-sectional view of the fifth figure, the eighth (a) figure is the schematic perspective view of the silicon sponge 55 shown in the fourth figure, and the eighth (b) figure is the silicon shown in the eighth (a) figure. A schematic front view of the sponge 55. Fig. 9(a) is a front view of the supporting member 56 shown in Fig. 4, and Fig. 9(b) is a sectional view taken along line B-B of Fig. 9(a). In the ninth (b) figure, the silicon sponge 55 supported by the supporting member 56 is depicted by a dotted line (dotted line). The tenth figure is the C-C line cross-sectional view of the seventh figure.

As shown in FIG. 7, the two ends 55 c and 55 d of the silicon sponge 55 are supported by the supporting member 56, and the two ends 55 c and 55 d of the silicon sponge 55 are fixed to the supporting member 56 by the fixing unit 70 described later.

As shown in the eighth (a) and the eighth (b), the silicon sponge 55 has fixing protrusions 55e, 55f protruding from both sides of the silicon sponge 55, respectively. The fixing protrusions 55e and 55f extend along the length direction of the silicon sponge 55. The fixing protrusion 55e constitutes a part of one end 55c of the silicon sponge 55, and the fixing protrusion 55f constitutes a part of the other end 55d of the silicon sponge 55.

As shown in FIG. 9(a) and FIG. 9(b), a recess 57 is formed on the front surface 56a of the support member 56. As shown in FIG. The recess 57 is formed at a position sandwiched between the two ends 58 and 59 of the support member 56. That is, the support member 56 includes: a recessed portion area where the recessed portion 57 is formed; and two end areas respectively located outside the recessed portion area and constituting the two end portions 58 and 59 of the support member 56 respectively. One end 55c of the silicon sponge 55 is a part of the silicon sponge 55 to which one end 58 (that is, one end region) of the support member 56 opposes. In this embodiment, the end 55c of the silicon sponge 55 including the fixing protrusion 55e is in contact with the end 58 of the supporting member. One side end area of the support member 56 consists of a fixed area opposite to the fixed protrusion 55e, and an end of the silicon sponge 55 other than the fixed protrusion 55e. 55c is formed by the opposite supporting area. Similarly, the other end 55d of the silicon sponge 55 is a part of the silicon sponge 55 opposite to the other end 59 of the support member 56 (that is, the other end region). In this embodiment, the end portion 55d of the silicon sponge 55 including the fixing protrusion 55f is in contact with the end portion 59 of the supporting member. The other end area of the support member 56 is composed of a fixed area facing the fixing protrusion 55f and a supporting area facing the end 55d of the silicon sponge 55 other than the fixing protrusion 55f. The supporting area is an area formed on the supporting member 56 to reliably support the silicon sponge 55, and the fixing area is an area formed by fixing the two ends 55c and 55d of the silicon sponge 55 to the supporting member 56 by the fixing unit 70 described later. .

By forming the recess 57 in the support member 56, the front surface 56 a of the support member 56 is divided into a bottom surface 57 a of the recess 57, a front surface 58 a of the end 58, and a front surface 59 a of the end 59. That is, the front face 58a of the end 58 corresponds to the front face of the support member 56 in one end region, and the front face 59a of the end 59 corresponds to the front face of the support member 56 in the other end region. The bottom surface 57a of the recess 57 of this embodiment is connected to the front surface 58a of one end 58 of the support member 56 via one side 57b of the recess 57, and is connected to the other end of the support member 56 via the other side 57c of the recess 57 59 before 59a.

As shown in the seventh figure, the front faces 58a, 59a of the both ends 58 and 59 of the supporting member 56 are in contact with the back face 55b on the opposite side to the pressing face 55a of the silicon sponge 55. More specifically, the front faces 58a, 59a of both ends 58 and 59 of the support member 56 and the back of the end 55c of the silicon sponge 55 including the fixing protrusion 55e, and the end 55d of the silicon sponge 55 including the fixing protrusion 55f, respectively The back contact. The back surface of the support member 56 (that is, the surface on the opposite side to the front surface 56 a of the support member 56) 56 b is in contact with the pad body 54.

Next, the fixing unit 70 that fixes the both ends 55c and 55d of the silicon sponge 55 to the support member 56 will be described with reference to the seventh and tenth figures. The fixing unit 70 is respectively arranged at both ends of the pressing pad 50 and has a fixing block 71 and a screw 72 screwed into the fixing block 71. As shown in FIG. 10, the fixed block 71 of the fixed unit 70 has a stepped portion 71a and has an L-shaped cross-sectional shape. The step portion 71a has a The shape of the fixing protrusion 55e (or 55f) of the silicon sponge 55 shown in Fig. 8(a) and Fig. 8(b), the fixing protrusion 55e (or 55f) is embedded in the stepped portion 71a. The fixing block 71 is formed with a screw hole 71b into which the screw 72 is screwed, and a through hole 56c into which the screw 72 is inserted is formed in the fixing area of each end area of the support member 56 (refer to the ninth (b) figure). The through hole 56c is formed at a position corresponding to the screw hole 71b. Both ends of the pad body 54 are also respectively formed with through holes 54c into which the screws 72 are inserted, and these through holes 54c are formed at positions corresponding to the screw holes 71b.

In a state where the two ends 55c and 55d of the silicon sponge 55 are supported on the two ends 58 and 59 of the support member 56, the stepped portion 71a of the fixed block 71 is fitted into the fixing protrusions 55e and 55f of the support member 56, respectively. In this state, the screw 72 is inserted into the through hole 54c of the pad body 54 and the through hole 56c of the support member 56, and is further screwed into the screw hole 71b of the fixing block 71. The two ends 55c and 55d of the silicon sponge 55 are fixed to the supporting member 56 by this fixing action, and the supporting member 56 for fixing the silicon sponge 55 can be fixed to the pad body 54.

The fixing unit for fixing the silicon sponge 55 and the supporting member 56 to the pad body 54 is not limited to the above-mentioned embodiment including the fixing block 71 and the screw 72. For example, it is also possible to clamp the ends 55c, 55d of the silicon sponge 55, the support member 56 and the clamp of the pad body 54 to fix the silicon sponge 55 to the support member 56, and at the same time fix the silicon sponge 55 and the support member 56 to垫身54。 Pad body 54. Or, the two ends 55c, 55d of the silicone sponge 55 can be joined (that is, fixed) to the two ends 58, 59 of the support member 56 with an adhesive, and the support of the silicone sponge 55 can be fixed by the adhesive or screws. The member 56 is fixed to the pad body 54.

The eleventh figure is a diagram showing how the polishing head 30 polishes the groove B of the wafer W. When polishing the groove portion of the wafer W, as shown in FIG. 11, the inclination angle of the polishing head 30 is changed intermittently or continuously by the above-mentioned tilting mechanism, and the polishing belt 23 is contacted by the pressing pad 50 At the groove of wafer W. During grinding, the grinding belt 23 can also be fed at a specified speed by the belt feeding mechanism 42.

Furthermore, the polishing head 30 having the pressing pad 50 of this embodiment can polish the top edge and the bottom edge of the wafer W. That is, as shown in FIG. 12, the polishing head 30 is tilted upward by the above-mentioned tilting mechanism, and the polishing tape 23 is pressed against the top edge of the wafer W by the protrusion 54a, so that the top edge can be polished. Furthermore, as shown in FIG. 13, the polishing head 30 is tilted downward, and the polishing tape 23 is pressed against the bottom edge of the wafer W by the protrusion 54b, so that the bottom edge can be polished.

Therefore, the polishing head 30 of this embodiment can polish the entire periphery of the wafer W including the top edge portion E1, the bevel portion B, and the bottom edge portion E2. The polishing head assemblies 1A to 1D (refer to the first figure) each have the polishing head 30. Therefore, in order to increase the throughput of the polishing device, all the polishing head assemblies 1A to 1D may polish the entire peripheral edge portion of the wafer W including the top edge portion E1, the bevel portion B, and the bottom edge portion E2. Alternatively, the polishing head assembly 1A may polish the top edge portion E1, the polishing head assembly 1B may polish the groove portion B, and the polishing head assembly 1C may polish the bottom edge portion E2.

In order to grind the groove B of the wafer W, when the silicon sponge 55 of the pressing pad 50 is pressed against the groove B of the wafer W with a specified force by the air cylinder 52, the silicon sponge 55 is folded back to the wafer. The groove B of W is deformed. At this time, a concave portion 57 is formed on the front surface 56a of the supporting member 56. Since both ends 55c and 55d of the silicon sponge 55 are supported by the supporting member 56, the silicon sponge 55 can easily enter the concave portion 57 of the supporting member 56.

Figure 14 is a schematic diagram showing the state where the silicon sponge 55 enters the recess 57 of the supporting member 56. Figure 15(a) shows a schematic diagram of the silicon sponge 55 deformed by folding back the groove B of the wafer W when the pressing surface 55a of the silicon sponge 55 of the pressing pad 50 is perpendicular to the flat surface of the wafer W Fig. 15(b) is a diagram showing the pressing force pattern in the contact area between the polishing tape 23 pressed by the pressing pad 50 shown in Fig. 15(a) and the groove B of the wafer W. Figure 16(a) is a schematic diagram of the silicon sponge 55 deformed by folding back the groove B of the wafer W when the pressing surface 55a of the silicon sponge 55 of the pressing pad 50 is inclined to the flat surface of the wafer W. tenth Fig. 6(b) is a diagram showing the pressing force pattern in the contact area between the polishing tape 23 pressed by the pressing pad 50 shown in Fig. 16(a) and the groove B of the wafer W.

Figures fourteenth to sixteenth (b) depict a patterned pressing pad 50 to help understand the invention. More specifically, only the silicon sponge 55, the supporting member 56, the pad body 54, and the fixing block 71 of the fixing unit 70 are schematically depicted. In addition, the fifteenth (a), fifteenth (b), sixteenth (a), and sixteenth (b) diagrams do not depict the polishing tape 23 in order to simplify the description, but the wafer During the polishing of the groove B of the W, as shown in FIG. 14, the pressing pad 50 presses the polishing tape 23 against the groove B of the wafer W. More specifically, the pressing surface 55a of the silicon sponge 55 of the pressing pad 50 directly contacts the back surface of the polishing tape 23. In this state, the pressing pad 50 presses the front surface of the polishing tape 23 against the groove B of the wafer W (polishing surface). During polishing, the width of the polishing tape 23 in contact with the groove B of the wafer W corresponds to the width of the pressing surface 55a of the silicon sponge 55 in contact with the groove B of the wafer W via the polishing tape 23.

As shown in Fig. 14, when the silicon sponge 55 of the pressing pad 50 is pressed against the groove B of the wafer W with the specified force by the air cylinder 52, the silicon sponge 55 is deformed and can enter the support member 56.之槽57。 The recess 57. The back surface 55b of the silicon sponge 55 that has entered the recess 57 of the support member 56 is in contact with the bottom surface 57a of the recess 57. The silicon sponge 55 is deformed along the wafer as shown in the fifteenth (a) and sixteenth (a) figures. The shape of the groove B of the W. Therefore, by forming the recess 57 into which the silicon sponge 55 can enter the supporting member 56, the silicon sponge 55 can be deformed into a shape along the groove B of the wafer W. As a result, even if the pressing surface 55a of the silicon sponge 55 is inclined with respect to the wafer W, the polishing tape 23 can maintain the width of the groove B contacting the wafer W constant. That is, the width W1 of the polishing tape 23 in contact with the groove B of the wafer W when the pressing surface 55a is perpendicular to the flat surface of the wafer W (refer to the fifteenth (a) figure) is opposed to the pressing surface 55a When the flat surface of the circle W is inclined, the width W2 (refer to the sixteenth (a) drawing) of the polishing tape 23 contacting the groove B of the wafer W is the same.

The silicon sponge 55 is a foam containing a plurality of microscopic voids inside. The silicon sponge 55 is formed, for example, by foaming silicon in a forming mold. The surface of the silicon sponge 55 after being taken out from the molded model is a smooth and flat surface without unevenness. However, when cutting the flat surface, the voids in the silicon sponge 55 will be exposed. That is, irregularities appear on the surface of the silicon sponge 55 to be cut. For example, when the pressing surface 55a and/or the back surface 55b of the silicon sponge 55 are cut in order to adjust the height of the silicon sponge 55, unevenness will appear on the cut pressing surface 55a and/or the back surface 55b.

When the silicon sponge 55 with unevenness on the pressing surface 55a and/or the back surface 55b is pressed against the groove B of the wafer W, the unevenness of the pressing surface 55a and/or the back surface 55b is destroyed, and the silicon sponge 55 cannot be deformed along the wafer. The desired shape of the groove B of the W. Therefore, it is not suitable to perform processing such as cutting processing on the pressing surface 55a and/or the back surface 55b of the silicon sponge 55, and to form the pressing surface 55a and/or the back surface 55b as a smooth and flat surface.

The seventeenth figure is a photograph showing the polishing marks added to the polishing tape 23 when the polishing tape 23 is pressed against the groove portion B of the wafer W by the pressing pad 50 of the present embodiment to polish the groove portion B. The seventeenth figure shows a plurality of polishing marks when the bevel portion B of the wafer W is polished by changing the inclination angle θ of the pressing surface 55a to the flat surface of the wafer W every 10°. The inclination angle θ is 0 degrees when the pressing surface 55a of the silicon sponge 55 of the pressing pad 50 is perpendicular to the flat surface of the wafer W. The inclination angle θ is a positive value when the pressing surface 55a is inclined in the direction in which the upper end of the pressing surface 55a is close to the flat surface of the wafer W, and the pressing surface 55a is inclined in the direction away from the flat surface of the wafer W on the upper end of the pressing surface 55a. When it is a negative value.

From the photo in Figure 17, the length of the grinding marks is approximately the same at all inclination angles. For example, the length L1 of the polishing trace when the inclination angle θ is 0° is approximately the same as the length L2 of the polishing trace when the inclination angle θ is 70°. Therefore, by using the pressing pad 50 of this embodiment, the polishing tape 23 is opposed to the wafer W is inclined, and when the groove portion B of the wafer W is polished with the polishing tape 23, the polishing tape 23 of the polishing tape 23 in contact with the wafer W can be The width remains constant. As a result, even if the inclination angle θ of the pressing surface 55a is changed, the polishing rate remains the same. Therefore, compared with the use of the conventional pressing pad 150 (refer to FIG. 24) to polish the groove B of the wafer W, the polishing can be achieved The processing capacity of the device is increased.

Furthermore, from the photograph in Figure 17, the color brightness in the central area of the polishing trace at the entire tilt angle θ is approximately the same as the color brightness in the area outside the polishing trace. This, as shown in the fifteenth (b) and sixteenth (b) figures, shows the pressing force F1 at the center of the contact area between the polishing belt 23 and the groove B of the wafer W, and the pressing force F1 between the polishing belt 23 and the wafer W The outside pressing force F2 of the contact area of the groove B of the W is approximately the same. Therefore, as compared with the polishing of the groove B of the wafer W using the conventional pressing pad 150 (refer to FIG. 24), the polishing tape 23 is less likely to be clogged in the center area of the polishing tape 23. As a result, since the polishing rate of the groove B of the wafer W does not decrease, the throughput of the polishing apparatus can be increased.

The silicon sponge (elastic member) 55 of this embodiment has a plurality of microscopic voids inside, but has a solid structure in which the pressing surface 55a and the back surface 55b of the silicon sponge 55 are deformed integrally. That is, the silicon sponge 55 does not form an internal space that only allows the pressing surface 55a of the silicon sponge 55 to deform. When the silicon sponge 55 has a hollow structure forming such an internal space, when the pressing pad 50 is pressed against the groove B of the wafer W, the pressing surface 55a of the silicon sponge 55 can also be along the circumferential direction of the wafer W bending. However, it is difficult to manage the deformation amount of the pressing surface 55a of the silicon sponge 55 at this time. When the pressing surface 55a of the silicon sponge 55 deforms greatly, the polishing tape 23 contacts the top edge portion E1 and/or the bottom edge portion E2 of the wafer W and damages the wafer W. Furthermore, the pressing force at the center of the contact area between the polishing belt 23 and the groove B of the wafer W is greater than the pressing force outside the contact area between the polishing belt 23 and the groove B of the wafer W. The central area is prone to clogging of the polishing belt 23.

In this embodiment, the both ends 58 and 59 of the support member 56 having the recesses 57 support both ends 55c and 55d of the silicon sponge 55 having a solid structure. With this structure, when the pressing pad 50 is pressed against the groove B of the wafer W, the pressing surface 55a and the back surface 55b of the silicon sponge 55 are deformed integrally, and the silicon sponge 55 can be easily deformed. Invade the recess 57. The silicon sponge 55 entering the recess 57 deforms along the shape of the groove B of the wafer W in a state where the back surface 55b of the silicon sponge 55 is supported by the bottom surface 57a of the recess 57. Therefore, the shape of the recess 57 (for example, the width of the recess 57, the depth Dp, etc.) and the support are based on the shape of the groove portion of the wafer W, the width of the polishing tape 23, the force of pressing the polishing tape 23 against the wafer W, etc. The width Wd of the support area in the member 56 (refer to the ninth (b) figure) is optimized, and the deformation amount of the silicon sponge 55 can be managed to a desired value. Furthermore, as shown in the fifteenth (b) and sixteenth (b) figures, the pressing force F1 at the center of the contact area between the polishing tape 23 and the groove B of the wafer W can be made to be the same as the pressing force F1 in the polishing tape 23 and the pressing force F2 outside the contact area of the groove portion B of the wafer W are approximately the same.

An experiment was performed to polish the groove B of the bare silicon wafer by using the polishing head 30 with the pressing pad 50 described above. The experiment measures the inclination angle of the polishing head 30 (that is, the inclination angle θ of the pressing surface 55a of the silicon sponge 55) at 0°, 70°, and -70°, and the polishing belt 23 is pressed by the pressing pad 50 at a specified time ^{Polishing area (μm 2} ) at the groove B of a bare silicon wafer. Further experiments were performed to change the width Wd of the support region in the support member 56 and the depth Dp of the recess 57 (refer to the ninth (b) drawing). ^{Furthermore, in the comparative example, the polishing area (μm 2} ) when the polishing tape 23 is pressed against the groove portion B of the bare silicon wafer with the conventional pressing pad 150 (refer to FIG. 24) is measured under the same conditions. Table 1 shows the experimental results when the inclination angle of the polishing head 30 is 0°, Table 2 shows the experimental results when the inclination angle of the polishing head 30 is 70°, and Table 3 shows the experimental results when the inclination angle of the polishing head 30 is -70° result.

From Table 1 to Table 3, it is understood that the polishing area of the bare silicon wafer polished by the above-mentioned pressing pad 50 is larger than that of the bare silicon wafer polished by the conventional pressing pad 150. Therefore, the bare silicon wafer W can be effectively polished by using the pressing pad 50 of this embodiment. Furthermore, it is understood that when the width Wd of the support region in the support member 56 is 3 mm or 5 mm, and the depth Dp of the recess 57 is 0.5 mm, the polishing area is greatly increased.

In addition, another experiment was performed in which the polishing head 30 with the above-mentioned pressing pad 50 was used to polish the entire groove portion of the wafer on which the silicon nitride film was laminated on the bare silicon wafer. For the convenience of description, a wafer W with a silicon nitride film laminated on a bare silicon wafer is referred to as a silicon nitride (SiN) wafer. In addition, in the experiment, the polishing head 30 with the pressing pad 50 was intermittently tilted, and the time required to polish the silicon nitride film of the silicon nitride wafer to about 200 nm at various angles was measured. In addition, the experiment was performed multiple times by changing the width Wd of the support region in the support member 56 and the depth Dp of the recess 57 (refer to the ninth (b) figure). Furthermore, in the comparative example, it takes time to intermittently incline the polishing head 30 with the conventional pressing pad 150 (refer to FIG. 24) to polish the silicon nitride film of the silicon nitride wafer at various angles at about 200 nm.

In addition, the results of the experiment are shown in the graph of Figure 18. In the graph shown in FIG. 18, the vertical axis represents the time required to polish the silicon nitride film to about 200 nm, and the horizontal axis represents the tilt angle of the polishing head 30. In the graph shown in FIG. 18, the result of the polishing head 30 with the conventional pressing pad 150 of the comparative example is drawn with a thick solid line.

It can be understood from the graph shown in Fig. 18 that the polishing head 30 with the pressing pad 50 of this embodiment takes longer to polish a silicon nitride film than the polishing head 30 with the pressing pad 150 in the past. The time is short. In particular, when the pressing pad 50 with the depth Dp of the recess 57 of the support member 56 of 0.5 mm is used, the polishing time of the silicon nitride film can be greatly reduced. More specifically, when the polishing head 30 with the pressing pad 150 of the past is used, the polishing time of the silicon nitride film in the entire groove portion of the silicon nitride wafer is 69 seconds. When the polishing head 30 having the pressing pad 50 with the depth Dp of the recess 57 of the support member 56 of 0.5 mm is used, the polishing time of the silicon nitride film in the entire groove portion of the silicon nitride wafer is 52 seconds. Therefore, the polishing time when the silicon nitride film is polished by the polishing head 30 with the above-mentioned pressing pad 50 is about 25% shorter than the polishing time when the silicon nitride film is polished by the polishing head 130 with the conventional pressing pad 150.

The nineteenth figure is a cross-sectional view showing another embodiment of the pressing pad 50. Since the unspecified configuration of this embodiment is the same as that of the embodiment described with reference to FIGS. 4 to 10, repetitive descriptions are omitted. The recess 57 of the pressing pad 50 shown in FIG. 19 has a curved bottom surface 57a. More specifically, the bottom surface 57a of the recess 57 has an arc-shaped curved shape. The bottom surface 57a of the recess 57 in this embodiment is directly connected to the front surfaces 58a, 59a of the both ends 58 and 59 of the supporting member 56. That is, the recess 57 of this embodiment does not have the side surfaces 57b and 57c of the recess 57 shown in the ninth (a) and the ninth (b). In one embodiment, the curved bottom surface 57a may be connected to the front surfaces 58a, 59a of the two ends 58, 59 of the support member 56 via the side surfaces 58b, 58c of the recess 57.

The silicon sponge 55 can also enter the concave portion 57 having the curved bottom surface 57a. The back surface 55b of the silicon sponge 55 that has entered the recess 57 of the support member 56 contacts the curved bottom surface 57a of the recess 57, and the silicon sponge 55 is deformed into a shape along the groove B of the wafer W. Therefore, when the polishing tape 23 is inclined to the wafer W and the groove B of the wafer W is polished with the polishing tape 23, the width of the polishing tape 23 in contact with the wafer W can be maintained constant. Furthermore, the pressing force in the contact area between the polishing tape 23 and the groove B of the wafer W can be made uniform. The bottom surface 57a of the recess 57 preferably has an arc shape with a radius of curvature that is substantially the same as the radius of curvature of the groove B of the wafer W. At this time, when the back surface 55b of the silicon sponge 55 entering the recess 57 of the support member 56 contacts the curved bottom surface 57a of the recess 57, the silicon sponge 55 can be deformed into the same shape as the groove B along the circumferential direction of the wafer W.

Figure 20 is a cross-sectional view of a pressing pad 50 according to another embodiment. Since the unspecified configuration of this embodiment is the same as that of the embodiment described with reference to FIGS. 4 to 10, repetitive descriptions are omitted. The pressing pad 50 shown in FIG. 20 has a thin plate 73 attached to the pressing surface 55a of the silicon sponge 55 in order to reduce friction with the back surface of the polishing belt 23. The thin plate 73 has a surface treated to reduce the coefficient of friction of Teflon (registered trademark) processing or the like, and the surface is in contact with the back surface of the polishing tape 23. Furthermore, in this embodiment, a thin plate 74 having the same structure as the thin plate 73 is attached to the back surface 55b of the silicon sponge 55.

Since the pressing surface 55a and the back surface 55b of the silicon sponge 55 are bonded with the thin plates 73 and 74 of the same composition, the pressing surface 55a of the silicon sponge 55 presses the groove B of the wafer W and the silicon sponge 55 is deformed. The back surface 55b of the silicon sponge 55 can be deformed according to the deformation of the pressing surface 55a of the silicon sponge 55. That is, the silicon sponge 55 appropriately enters the recess 57, and the silicon sponge 55 can be deformed into a shape along the groove B of the wafer W. As a result, even if the thin plate 73 is attached to the pressing surface 55a of the silicon sponge 55, the polishing tape 23 is inclined to the wafer W and the groove B of the wafer W is polished with the polishing tape 23, the wafer W can still be contacted. The width of the polishing belt 23 remains constant. Furthermore, the pressing force in the contact area between the polishing tape 23 and the groove B of the wafer W can be made uniform.

Figure 21 is a cross-sectional view of a pressing pad 50 according to another embodiment. Since the unspecified configuration of this embodiment is the same as that of the embodiment described with reference to FIGS. 4 to 10, repetitive descriptions are omitted. The pressing surface 55a of the silicon sponge 55 of the pressing pad 50 shown in FIG. 21 is formed with a plurality of grooves 78 (two in FIG. 21) extending from the pressing surface 55a to the back surface 55b. These grooves 78 are arranged parallel to each other at equal intervals. By forming a plurality of grooves 78 on the pressing surface 55 a of the silicon sponge 55, a plurality of (three in the twenty-first figure) block 80 is formed in the silicon sponge 55. In this embodiment, the front surface of a plurality of blocks 80 constitutes the pressing surface 55 a of the silicon sponge 55.

When a silicon sponge 55 formed with a plurality of blocks 80 is used, the silicon sponge 55 is easily deformed into a shape along the groove B of the wafer W. As a result, when the polishing tape 23 is inclined to the wafer W and the groove B of the wafer W is polished with the polishing tape 23, the width of the polishing tape 23 in contact with the wafer W can be maintained constant. Furthermore, the pressing force of the contact area between the polishing tape 23 and the groove B of the wafer W can be made uniform.

Figure 22 is a cross-sectional view of a pressing pad 50 according to another embodiment. Since the configuration not specifically described in this embodiment is the same as the embodiment described with reference to Figure 21, it is omitted The description is repeated. The silicon sponge 55 of the pressing pad 50 shown in FIG. 22 is also formed with a plurality of grooves 78 extending from the pressing surface 55a to the back surface 55b. Therefore, a plurality of blocks 80 are formed in the silicon sponge 55 of the pressing pad 50 shown in FIG. 22.

Grinding stones 82 are respectively installed in front of a plurality of block bodies 80 of the silicon sponge 55 shown in FIG. 22. The grinding stone 82 is a grinding tool for grinding the groove portion B of the wafer W. That is, in this embodiment, instead of the polishing belt 23, the grindstone 82 is used as a polishing tool. Therefore, when the pressing pad 50 shown in FIG. 22 is used, since the above-mentioned polishing tape supply mechanism 2A to 2D is not required, the polishing device can be manufactured in a small size and inexpensively.

When the bevel portion B of the wafer W is polished using the polishing head 30 having the pressing pad 50 of this embodiment, the silicon sponge 55 is also deformed into a shape along the bevel portion B of the wafer W. As a result, when the grindstone 82 is inclined to the wafer W and the groove portion B of the wafer W is polished with the grindstone 82, the width of the grindstone 82 in contact with the wafer W can be maintained constant. Furthermore, the pressing force of the contact area between the grindstone 82 and the groove B of the wafer W can be made uniform.

The present invention is not limited to the above-mentioned embodiment. For example, in the embodiments shown in FIG. 20 to FIG. 22, the bottom surface 57a of the recess 57 may also have the curved shape shown in FIG. Furthermore, the grindstone 82 shown in Fig. 22 can also be installed on the pressing surface 55a of the silicon sponge 55 shown in Fig. 7 or Fig. 19. At this time, the grindstone 82 may be attached to the entire pressing surface 55a, or the grindstone 82 may be attached to only a part of the pressing surface 55a. For example, the grindstone 82 is only attached to a part of the pressing surface 55a deformed when the pressing pad 50 is pressed against the groove B of the substrate.

The above-mentioned embodiments are described for the purpose of being able to carry out the present invention by those who have general knowledge in the technical field to which the present invention belongs. Of course, those skilled in the art can form various modifications of the above-mentioned embodiments, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to The recorded implementation forms should be interpreted in the widest range based on the technical ideas defined by the scope of the patent application.

50: press pad

54: Pad body

54c: Through hole

55: Elastic part (silicon sponge)

55a: pressing surface

55b: back

55c, 55d: both ends

55e, 55f: fixed protrusion

56: Supporting member

56a: front

56b: back

56c: Through hole

57: recess

57a: bottom surface

57b: one side

57c: the other side

58: One end

58a: front

59: The other end

59a: front

70: fixed unit

71: fixed block

71b: Screw hole

72: Screw

Claims (14)

A polishing device, characterized by comprising: a substrate holding part which holds and rotates the substrate; and a pressing pad which presses the abrasive tool to the peripheral edge of the substrate held in the substrate holding part; the pressing pad has: An elastic member having a pressing surface for pressing the peripheral edge portion of the substrate via the abrasive tool; a supporting member supporting the elastic member; and a fixing unit fixing both ends of the elastic member to the supporting member, respectively ; On the front surface of the support member is formed a recess into which the elastic member can enter, the elastic member has fixing protrusions respectively protruding from both sides of the elastic member, each fixing unit is provided with a fixing block, the fixing block has for the fixing protrusion to be embedded的段差部。 The difference. Such as the polishing device of the first item in the scope of patent application, wherein the bottom surface of the aforementioned concave portion is curved. A polishing device, characterized by comprising: a substrate holding part which holds and rotates the substrate; and a pressing pad which presses the abrasive tool to the peripheral edge of the substrate held in the substrate holding part; the pressing pad has: An elastic member having a pressing surface for pressing the peripheral edge portion of the substrate via the abrasive tool; and a supporting member supporting the elastic member; a recess into which the elastic member can enter is formed on the front surface of the supporting member, wherein A thin plate is attached to the back surface of the elastic member on the opposite side of the pressing surface. For example, the polishing device of any one of items 1 to 3 in the scope of the patent application, wherein the aforementioned abrasive tool is composed of a polishing belt. A polishing device, characterized by comprising: a substrate holding part which holds and rotates the substrate; and a pressing pad which presses the abrasive tool to the peripheral edge of the substrate held in the substrate holding part; the pressing pad has: An elastic member having a pressing surface for pressing the peripheral edge portion of the substrate via the abrasive tool; and a supporting member supporting the elastic member; a recess into which the elastic member can enter is formed on the front surface of the supporting member, wherein The pressing surface of the elastic member is formed with a groove extending toward the back surface opposite to the pressing surface, and the elastic member has a block divided by the groove. For example, the polishing device of item 5 of the scope of patent application, wherein the abrasive tool is a grindstone installed in front of the cube body. A pressing pad that presses an abrasive tool for polishing the peripheral edge of a substrate against the peripheral edge, and is characterized by having: an elastic member having a pressing surface for pressing the peripheral edge of the substrate via the abrasive; and a supporting member Supporting the elastic member; and a fixing unit, which fixes both ends of the elastic member to the supporting member, respectively; a recess into which the elastic member can enter is formed on the front surface of the supporting member, and the elastic member has Two fixed protrusions protruding from two side surfaces respectively, and each fixed unit is provided with a fixed block, and the fixed block has a stepped portion for the fixing protrusion to be embedded. Such as the pressing pad of item 7 in the scope of patent application, wherein the bottom surface of the aforementioned concave portion is curved. A pressing pad that presses an abrasive tool for polishing the peripheral edge of a substrate against the peripheral edge, and is characterized by having: an elastic member having a pressing surface for pressing the peripheral edge of the substrate via the abrasive; and a supporting member, which It supports the elastic member; a recess into which the elastic member can enter is formed on the front surface of the support member, and a thin plate is attached to the back surface of the elastic member on the opposite side of the pressing surface. For example, the pressing pad of any one of items 7 to 9 in the scope of patent application, wherein the aforementioned abrasive tool is composed of an abrasive belt. A pressing pad, which presses an abrasive tool for polishing the peripheral edge of a substrate against the peripheral edge, and is characterized in that it has: An elastic member having a pressing surface for pressing the peripheral edge portion of the substrate via the abrasive; and a supporting member supporting the elastic member; a recess into which the elastic member can enter is formed on the front surface of the supporting member, wherein the elastic The pressing surface of the member is formed with a groove extending toward the back surface opposite to the pressing surface, and the elastic member has a block divided by the groove. For example, the pressing pad of item 11 in the scope of patent application, wherein a grinding stone used as the abrasive tool is installed on the front surface of the block body. Such as the grinding device of the first item of the scope of patent application, wherein the fixing unit is further provided with screws that are screwed into the fixing block. For example, the pressing pad of item 8 of the scope of patent application, wherein the fixing unit is further provided with screws that are screwed into the fixing block.

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