Mount and polishing apparatus

Abstract

To provide a polishing pad capable of suppressing partial supply shortage of a polishing liquid.SOLUTION: According to an aspect of the present invention, there is provided a polishing pad to be mounted on a polishing apparatus for polishing a workpiece, the polishing pad including a disk-shaped base including a first surface and a second surface and having a recess provided on the first surface side, a porous member provided in the recess of the base, a polishing layer fixed to the second surface side of the base, and a plurality of through-holes penetrating the polishing layer and connected to the porous member, wherein a polishing liquid supplied to the porous member is supplied to the plurality of through-holes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polishing pad for polishing a workpiece, a mount on which the polishing pad is mounted, and a polishing apparatus equipped with the mount. [Background technology]

[0002] The device chip manufacturing process uses a wafer in which devices are formed in multiple areas defined by multiple streets (planned division lines) arranged in a grid pattern. By dividing this wafer along the streets, multiple device chips, each equipped with a device, are obtained. The device chips are incorporated into various electronic devices, such as mobile phones and personal computers.

[0003] In recent years, with the miniaturization of electronic devices, there has been a demand for thinner device chips. Therefore, a grinding device is sometimes used to thin wafers before they are divided. The grinding device includes a chuck table that holds the workpiece and a grinding unit that grinds the workpiece, and a grinding wheel including a grinding stone is attached to the grinding unit. The wafer is held by the chuck table, and the grinding stone is brought into contact with the wafer while the chuck table and grinding wheel are rotated, thereby grinding and thinning the wafer (see Patent Document 1).

[0004] After a wafer is ground by a grinding wheel, its surface (the surface to be ground) is left with processing marks such as minute irregularities and scratches. When a wafer in this state is divided to produce device chips, the processing marks remain on the device chips, reducing their flexural strength (bending strength). Therefore, the ground wafer is polished using a polishing device. The polishing device includes a chuck table for holding the workpiece and a polishing unit for polishing the workpiece, and a disc-shaped polishing pad is attached to the polishing unit. The wafer is held by the chuck table, and the polishing pad is brought into contact with the wafer while rotating the chuck table and the polishing pad, thereby polishing the wafer (see Patent Document 2). This flattens the surface to be ground of the wafer and removes the processing marks remaining on the surface to be ground. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-288881 [Patent Document 2] Japanese Patent Application Publication No. 8-99265 Summary of the Invention [Problem to be solved by the invention]

[0006] When polishing a workpiece, a polishing device is sometimes used in which a polishing pad is positioned so that it overlaps the entire workpiece. In this case, the polishing liquid is supplied to the center of the workpiece through a polishing liquid supply path formed to penetrate the center of the polishing unit and the polishing pad. The polishing liquid supplied to the workpiece then spreads from the center to the outer edge of the workpiece due to the centrifugal force of the rotating workpiece. As a result, the polishing liquid is supplied to the entire workpiece.

[0007] However, depending on the size of the workpiece and the polishing conditions (such as the rotation speed of the workpiece and polishing pad, and the amount of polishing liquid supplied), the polishing liquid supplied to the center of the workpiece may not spread to the outer edge of the workpiece, resulting in a shortage of polishing liquid at the outer periphery of the workpiece. In this case, processing defects are likely to occur at the outer periphery of the workpiece.

[0008] The present invention has been made in consideration of such problems, and aims to provide a polishing pad and mount that can suppress a partial shortage of polishing liquid supply, and a polishing apparatus equipped with the mount. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a mount that is provided in a polishing apparatus for polishing a workpiece and on which a polishing pad is attached, the mount comprising: a disk-shaped base having a first surface and a second surface and a recess provided on the second surface side; a porous member provided in the recess of the base; and a polishing liquid supply path extending from the first surface of the base to the porous member, and the mount supplies the polishing liquid supplied to the polishing liquid supply path via the porous member to the polishing pad attached to the second surface side of the base.

[0010] Preferably, the mount supplies the polishing liquid from the porous member to a plurality of through holes that penetrate the polishing pad.

[0011] Furthermore, according to another aspect of the present invention, there is provided a polishing apparatus for polishing a workpiece, comprising: a chuck table for holding the workpiece; and a polishing unit for polishing the workpiece held by the chuck table, wherein the polishing unit comprises a spindle and a mount fixed to the tip of the spindle and on which a polishing pad is attached, the mount comprising: a disk-shaped base having a first surface and a second surface and a recess provided on the second surface side; a porous member provided in the recess of the base; and a polishing liquid supply path extending from the first surface of the base to the porous member, wherein the polishing apparatus supplies the polishing liquid supplied to the polishing liquid supply path via the porous member to the polishing pad attached to the second surface side of the base.

[0012] Preferably, the polishing apparatus supplies the polishing liquid from the porous member to a plurality of through holes penetrating the polishing pad. [Effects of the Invention]

[0013] The polishing pad and mount according to one aspect of the present invention include a porous member through which a polishing liquid is supplied. This allows the polishing liquid to flow from the center of the polishing pad and mount toward the outer periphery, facilitating the supply of polishing liquid not only to the center but also to the outer periphery of the workpiece. As a result, partial shortages of polishing liquid are suppressed, and processing defects are prevented. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a polishing apparatus. [Figure 2] FIG. 2(A) is a perspective view showing the upper surface side of the first mount, and FIG. 2(B) is a perspective view showing the lower surface side of the first mount. [Figure 3] FIG. 3(A) is a perspective view showing the upper surface side of the first polishing pad, and FIG. 3(B) is a perspective view showing the lower surface side of the first polishing pad. [Figure 4] 1 is a partial cross-sectional side view showing a polishing apparatus that polishes a workpiece with a first polishing pad attached to a first mount. [Figure 5] FIG. 5(A) is a perspective view showing the upper surface side of the second mount, and FIG. 5(B) is a perspective view showing the lower surface side of the second mount. [Figure 6] FIG. 6(A) is a perspective view showing the upper surface side of the second polishing pad, and FIG. 6(B) is a perspective view showing the lower surface side of the second polishing pad. [Figure 7] 10 is a partial cross-sectional side view showing a polishing apparatus that polishes a workpiece with a second polishing pad attached to a second mount. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment according to one aspect of the present invention will be described below with reference to the accompanying drawings. First, a configuration example of a polishing apparatus according to this embodiment will be described. FIG. 1 is a perspective view showing a polishing apparatus 2. In FIG. 1, the X-axis direction (first horizontal direction, front-rear direction) and the Y-axis direction (second horizontal direction, left-right direction) are perpendicular to each other. Furthermore, the Z-axis direction (vertical direction, height direction, up-down direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0016] The polishing apparatus 2 includes a rectangular parallelepiped base 4 that supports or houses each of the components that make up the polishing apparatus 2. At the front end of the base 4, cassette placement areas (cassette placement tables) 6a and 6b are provided on which cassettes 8a and 8b are placed. The cassettes 8a and 8b are containers that can hold a plurality of workpieces 11, and are placed on the cassette placement areas 6a and 6b, respectively. The cassette 8a contains the workpiece 11 before polishing, and the cassette 8b contains the workpiece 11 after polishing.

[0017] For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as silicon, and has a front surface 11a and a back surface 11b that are generally parallel to each other. The workpiece 11 is divided into a plurality of rectangular regions by a plurality of streets (planned division lines) that are arranged in a grid pattern so as to intersect with each other. Furthermore, devices (not shown), such as ICs (Integrated Circuits), LSIs (Large Scale Integration), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices, are formed on the front surface 11a side of each of the plurality of regions divided by the streets.

[0018] By dividing the workpiece 11 along the streets, a plurality of device chips each equipped with a device are manufactured. Furthermore, by grinding the back surface 11b of the workpiece 11 before division to thin the workpiece 11, thinned device chips are obtained. Furthermore, by polishing the back surface 11b of the workpiece 11 after grinding using a polishing device 2, the back surface 11b (grinding surface) of the workpiece 11 is flattened, and processing marks such as minute irregularities and scratches remaining on the back surface 11b of the workpiece 11 are removed.

[0019] When the back surface 11b of the workpiece 11 is polished by the polishing apparatus 2, a protective member 13 is attached to the front surface 11a of the workpiece 11. The protective member 13 can be a tape having a circular film-like substrate and an adhesive layer (glue layer) provided on the substrate. For example, the substrate is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate, and the adhesive layer is made of an epoxy-based, acrylic-based, or rubber-based adhesive. The adhesive layer may also be an ultraviolet-curable resin that hardens when exposed to ultraviolet light. The protective member 13 protects the front surface 11a (device side) of the workpiece 11.

[0020] The workpieces 11 are housed in a cassette 8a with a protective member 13 attached thereto. Then, the cassette 8a housing a plurality of workpieces 11 is placed on the cassette placement area 6a. There are no limitations on the type, material, shape, structure, size, etc. of the workpieces 11. For example, the workpieces 11 may be substrates made of semiconductors other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass (quartz glass, borosilicate glass, etc.), ceramics, resin, metal, etc. There are also no limitations on the type, number, shape, structure, size, arrangement, etc. of the devices.

[0021] An opening 4a is provided in an area located between the cassette placement areas 6a and 6b on the upper surface of the base 4. A first transport mechanism 10 for transporting a workpiece 11 is provided inside the opening 4a. An operation panel 12 for inputting various information (processing conditions, etc.) to the polishing apparatus 2 is also provided in front of the opening 4a.

[0022] A position adjustment mechanism (alignment mechanism) 14 that adjusts the position of the workpiece 11 is provided diagonally behind the first transport mechanism 10. The workpiece 11 stored in the cassette 8a is transported onto the position adjustment mechanism 14 by the first transport mechanism 10. The position adjustment mechanism 14 then adjusts the position of the workpiece 11 by clamping it. In addition, a second transport mechanism (loading arm) 16 that holds and rotates the workpiece 11 is provided near the position adjustment mechanism 14.

[0023] A rectangular opening 4b is provided in an area of ​​the upper surface of the base 4 that is located behind the second transfer mechanism 16, with the longitudinal direction aligned with the X-axis direction. A chuck table (holding table) 18 that holds the workpiece 11 is provided inside the opening 4b. The upper surface of the chuck table 18 is a flat surface that is roughly parallel to the horizontal plane (XY plane), and forms a holding surface 18a that holds the workpiece 11. The holding surface 18a is connected to a suction source (not shown), such as an ejector, via a suction passage (not shown), a valve (not shown), and the like, that are formed inside the chuck table 18.

[0024] An X-axis movement mechanism 20 is connected to the chuck table 18. For example, the X-axis movement mechanism 20 is a ball screw type movement mechanism that includes a ball screw (not shown) arranged along the X-axis direction and a pulse motor (not shown) that rotates the ball screw. The X-axis movement mechanism 20 also includes a table cover 22 that surrounds the chuck table 18, and accordion-shaped dust- and drip-proof covers 24 that are extendable and contractible along the X-axis direction are provided in front and behind the table cover 22. The table cover 22 and the dust- and drip-proof cover 24 cover the components of the X-axis movement mechanism 20 (the ball screw, pulse motor, etc.).

[0025] The workpiece 11, which has been aligned by the position adjustment mechanism 14, is transported onto the holding surface 18a of the chuck table 18 by the second transport mechanism 16 and held by the chuck table 18. Then, the X-axis movement mechanism 20 moves the chuck table 18 along the X-axis direction together with the table cover 22. In addition, the chuck table 18 is connected to a rotation drive source (not shown), such as a motor, that rotates the chuck table 18 around a rotation axis that is approximately parallel to the Z-axis direction.

[0026] A rectangular parallelepiped support structure 26 is provided at the rear end of the base 4. A Z-axis movement mechanism 28 is provided on the front side of the support structure 26. The Z-axis movement mechanism 28 includes a pair of guide rails 30 fixed along the Z-axis direction on the front side of the support structure 26. A flat moving plate 32 is slidably attached to the pair of guide rails 30.

[0027] A nut portion (not shown) is provided on the rear surface side (back surface side) of the moving plate 32. A ball screw 34, which is disposed along the Z-axis direction between a pair of guide rails 30, is threadedly engaged with this nut portion. A pulse motor 36 is connected to the end of the ball screw 34. When the ball screw 34 is rotated by the pulse motor 36, the moving plate 32 moves along the guide rails 30 in the Z-axis direction.

[0028] A support member 38 is provided on the front side (surface side) of the moving plate 32. The support member 38 supports a polishing unit 40 that polishes the workpiece 11 held by the chuck table 18.

[0029] The polishing unit 40 includes a hollow, cylindrical housing 42 supported by a support member 38. A cylindrical spindle 44 arranged along the Z-axis direction is rotatably housed in the housing 42. The tip end (lower end) of the spindle 44 is exposed to the outside of the housing 42, and a rotation drive source (not shown), such as a motor, is connected to the base end (upper end) of the spindle 44.

[0030] A disk-shaped mount 46 is fixed to the tip of the spindle 44. A disk-shaped polishing pad 48 for polishing the workpiece 11 is attached to the mount 46. For example, the polishing pad 48 is fixed to the underside of the mount 46 by a fastener such as a bolt 50. The polishing pad 48 rotates around a rotation axis that is approximately parallel to the Z-axis direction by power transmitted from a rotation drive source via the spindle 44 and the mount 46.

[0031] When polishing the workpiece 11, first, the chuck table 18 is moved by the X-axis movement mechanism 20, and the workpiece 11 is positioned below the polishing unit 40. Then, the polishing unit 40 is lowered at a predetermined speed by the Z-axis movement mechanism 28 while rotating the chuck table 18 and the spindle 44. As a result, the rotating polishing pad 48 comes into contact with the surface to be polished of the workpiece 11, and the workpiece 11 is polished.

[0032] A polishing liquid supply path 52 is formed inside the polishing unit 40 along the Z-axis direction. One end (upper end) of the polishing liquid supply path 52 is connected to a polishing liquid supply source 56 via a valve 54. The other end (lower end) of the polishing liquid supply path 52 is connected to the mount 46. When polishing the workpiece 11, the polishing liquid supplied from the polishing liquid supply source 56 flows into the mount 46 via the valve 54 and the polishing liquid supply path 52, and is supplied to the polishing pad 48 and the workpiece 11.

[0033] A third transfer mechanism (unloading arm) 58 that rotates while holding the workpiece 11 is disposed adjacent to the second transfer mechanism 16. A cleaning unit 60 that cleans the workpiece 11 is disposed in front of the third transfer mechanism 58. The workpiece 11 polished by the polishing unit 40 is transported from the chuck table 18 to the cleaning unit 60 by the third transfer mechanism 58, and is cleaned by the cleaning unit 60.

[0034] For example, the cleaning unit 60 includes a spinner table (not shown) that holds and rotates the workpiece 11, and a nozzle (not shown) that supplies a cleaning liquid such as pure water. The workpiece 11 is held by the spinner table, and the cleaning liquid is supplied to the workpiece 11 from the nozzle while the spinner table is rotating, thereby cleaning the workpiece 11. This removes processing debris, polishing liquid, and the like that are attached to the workpiece 11. Then, after cleaning, the workpiece 11 is carried out of the cleaning unit 60 by the first transport mechanism 10 and stored in the cassette 8b.

[0035] The polishing apparatus 2 also includes a control unit (control section, control device) 62 connected to each of the components (first transport mechanism 10, operation panel 12, position adjustment mechanism 14, second transport mechanism 16, chuck table 18, X-axis movement mechanism 20, Z-axis movement mechanism 28, polishing unit 40, valve 54, polishing liquid supply source 56, third transport mechanism 58, cleaning unit 60, etc.) that make up the polishing apparatus 2. The control unit 62 controls the operation of the polishing apparatus 2 by outputting control signals to each of the components of the polishing apparatus 2.

[0036] For example, the control unit 62 is configured by a computer and includes a calculation section that performs calculations necessary for the operation of the polishing apparatus 2, and a storage section that stores various information (data, programs, etc.) used for the operation of the polishing apparatus 2. The calculation section includes a processor such as a CPU (Central Processing Unit). The storage section includes memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0037] Next, a detailed description will be given of the mount 46 provided in the polishing unit 40 and the polishing pad 48 attached to the mount 46. Fig. 2(A) is a perspective view showing the upper surface side of the mount 46, and Fig. 2(B) is a perspective view showing the lower surface side of the mount 46.

[0038] The mount 46 includes a disk-shaped base 70. For example, the base 70 is made of a metal such as SUS (stainless steel), and includes a first surface (upper surface) 70a and a second surface (lower surface) 70b that are generally parallel to each other.

[0039] A cylindrical polishing liquid supply path (through hole) 70c is provided in the center of the base 70, penetrating the base 70 in the thickness direction from the first surface 70a to the second surface 70b. Furthermore, a plurality of cylindrical insertion holes (through holes) 70d are provided in the outer periphery of the base 70, penetrating the base 70 in the thickness direction from the first surface 70a to the second surface 70b. The plurality of insertion holes 70d are arranged at approximately equal intervals along the circumferential direction of the base 70. Although two insertion holes 70d are shown in FIGS. 2(A) and 2(B), there is no limit to the number of insertion holes 70d.

[0040] The first surface 70a side of the base 70 is connected to the spindle 44 (see FIG. 1). This connects the polishing liquid supply path 70c to the polishing liquid supply path 52 (see FIG. 1). The mount 46 may be the same member as the spindle 44, or may be a member independent of the spindle 44 that is detachable from the spindle 44. A bolt 50 (see FIG. 1) is inserted into the insertion hole 70d.

[0041] 3(A) is a perspective view showing the upper surface side of polishing pad 48, and FIG. 3(B) is a perspective view showing the lower surface side of polishing pad 48. Polishing pad 48 includes a disk-shaped base 72 attached to mount 46 and a disk-shaped polishing layer 78 fixed to base 72.

[0042] For example, the base 72 is made of a metal such as aluminum, an aluminum alloy, or stainless steel (SUS), or a resin such as polyphenylene sulfide (PPS), and includes a first surface (upper surface) 72a and a second surface (lower surface) 72b that are generally parallel to each other. A cylindrical recess (groove) 72c is provided in the center of the first surface 72a side of the base 72. The recess 72c is formed from the first surface 72a toward the second surface 72b side and is arranged concentrically with the base 72.

[0043] A disk-shaped porous member 74 is fitted into the recess 72c. The porous member 74 is made of a porous material such as porous ceramics, porous resin, or porous metal, and includes pores that communicate in the thickness direction and radial direction. The porosity of the porous member 74 (the ratio of the volume of pores to the volume of the porous member 74) is, for example, 20% to 80%, preferably 30% to 70%. For example, the porous member 74 is fixed to the bottom surface and side walls of the recess 72c with an adhesive. The depth of the recess 72c and the thickness of the porous member 74 are approximately equal, and the first surface 72a of the base 72 and the surface (upper surface) 74a of the porous member 74 are arranged on approximately the same plane.

[0044] In addition, an annular seal member 76 is provided on the first surface 72a side of the base 72. For example, the seal member 76 is an O-ring made of rubber, and is provided radially outside the recess 72c. The lower end of the seal member 76 is embedded in the first surface 72a side of the base 72, and the upper end of the seal member 76 is exposed from the base 72.

[0045] A plurality of cylindrical screw holes 72d are formed on the first surface 72a side of the outer periphery of the base 72, extending from the first surface 72a toward the second surface 72b. The screw holes 72d are provided in the same number as the insertion holes 70d (see FIGS. 2(A) and 2(B)) of the mount 46, and are arranged at approximately equal intervals along the circumferential direction of the base 72. The tips of the bolts 50 (see FIG. 1) are inserted and screwed into the screw holes 72d.

[0046] A disk-shaped polishing layer 78 having approximately the same diameter as the base 72 is fixed to the second surface 72b side of the base 72. The polishing layer 78 is made of nonwoven fabric, urethane foam, or the like, and includes a first surface (upper surface) 78a and a second surface (lower surface) 78b that are approximately parallel to each other. The polishing layer 78 also contains abrasive grains (fixed abrasive grains) as an abrasive material. For example, silica having a grain size of approximately 0.1 μm to 10 μm is used as the abrasive grains. However, the grain size, material, etc. of the abrasive grains are appropriately selected depending on the material, etc. of the object to be polished.

[0047] A plurality of cylindrical through-holes 78c are provided throughout the polishing layer 78, penetrating the polishing layer 78 in the thickness direction from the first surface 78a to the second surface 78b. For example, the plurality of through-holes 78c are arranged along a plurality of imaginary lines (12 in FIG. 3(B)) arranged radially in the radial direction of the polishing layer 78. However, there is no limit to the number and arrangement of the through-holes 78c.

[0048] The diameter of the base 72 and the polishing layer 78 is, for example, 300 mm or more and 500 mm or less. The through-hole 78c closest to the center of the polishing layer 78 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the center of the polishing layer 78. The through-hole 78c closest to the outer periphery of the polishing layer 78 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the outer periphery of the polishing layer 78.

[0049] Each of the multiple through holes 78c is provided at a position overlapping the porous member 74 and is connected to the porous member 74. Specifically, the upper end of the through hole 78c enters the second surface 72b side of the base 72 and reaches the lower surface of the porous member 74 (see FIG. 4).

[0050] 4 is a partial cross-sectional side view showing a polishing apparatus 2 that polishes a workpiece 11 with a polishing pad 48 attached to a mount 46. When grinding the workpiece 11 with the polishing pad 48, the workpiece 11 is first held by the chuck table 18. For example, the workpiece 11 is placed on the chuck table 18 so that the front surface 11a (the protective member 13 side) faces the holding surface 18a and the back surface 11b is exposed upward. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 18a, the workpiece 11 is suction-held by the chuck table 18 via the protective member 13.

[0051] The polishing pad 48 is also attached to the mount 46. Specifically, first, the polishing pad 48 is positioned so that the second surface 70b of the base 70 and the first surface 72a of the base 72 are in contact with each other. At this time, the angle of the polishing pad 48 is adjusted so that the insertion hole 70d of the base 70 and the screw hole 72d of the base 72 are connected. Then, the bolt 50 is inserted into the insertion hole 70d and screwed into the screw hole 72d. This tightens the bolt 50, and the polishing pad 48 is fixed to the mount 46.

[0052] The chuck table 18 holding the workpiece 11 is positioned below the polishing unit 40 by the X-axis movement mechanism 20 (see FIG. 1). At this time, the workpiece 11 is positioned so that the entire back surface 11b (surface to be polished) overlaps with the polishing layer 78 of the polishing pad 48. Then, while rotating the chuck table 18 and the spindle 44, the polishing unit 40 is lowered by the Z-axis movement mechanism 28 (see FIG. 1). As a result, the second surface 78b of the rotating polishing layer 78 is pressed against the back surface 11b of the workpiece 11, and the back surface 11b of the workpiece 11 is polished.

[0053] During polishing of the workpiece 11, the polishing liquid is supplied from the polishing liquid supply source 56 to the polishing liquid supply path 52 via the valve 54. Then, the polishing liquid that flows from the polishing liquid supply path 52 into the polishing liquid supply path 70c is supplied to the plurality of through-holes 78c through the pores inside the porous member 74. As a result, the polishing liquid flows out from the lower ends of the plurality of through-holes 78c and is supplied to the back surface 11b side of the workpiece 11.

[0054] Linear grooves (not shown) connecting the lower ends of the plurality of through-holes 78c may be provided on the second surface 78b side of the polishing layer 78. In this case, the cleaning liquid supplied to the workpiece 11 is more likely to flow along the back surface 11b of the workpiece 11, and the polishing liquid is more likely to spread over the entire back surface 11b side of the workpiece 11.

[0055] The polishing liquid used is one that does not contain abrasive grains. For example, an alkaline solution containing sodium hydroxide, potassium hydroxide, or the like, an acidic solution containing permanganate, or pure water, etc. However, if the polishing layer 78 does not contain abrasive grains (fixed abrasive grains), a chemical solution (slurry) in which abrasive grains (loose abrasive grains) are dispersed may be used as the polishing liquid.

[0056] When the back surface 11b of the workpiece 11 is polished with the polishing pad 48, the back surface 11b of the workpiece 11 is flattened and processing marks remaining on the back surface 11b of the workpiece 11 are removed. Then, when the polishing unit 40 descends to a predetermined position, the polishing amount of the workpiece 11 (the difference in thickness of the workpiece 11 before and after polishing) reaches a predetermined value, and polishing of the workpiece 11 is stopped.

[0057] When the polishing pad 48 is used to polish the workpiece 11, the centrifugal force of the rotating polishing pad 48 acts on the polishing liquid that has flowed from the polishing liquid supply path 70c into the porous member 74, causing the polishing liquid to flow and spread toward the outer periphery of the porous member 74 through the pores inside the porous member 74. The polishing liquid then flows from the porous member 74 into each of the multiple through holes 78c, and is supplied to the workpiece 11 from the lower ends of the multiple through holes 78c. As a result, a sufficient amount of polishing liquid is supplied over a wide range from the center of the workpiece 11 to the outer periphery.

[0058] 4 shows a configuration example in which the upper ends of the multiple through holes 78c extend into the second surface 72b of the base 72 and reach the lower surface of the porous member 74, but there are no limitations on the configuration of the porous member 74 and the through holes 78c as long as the porous member 74 and the multiple through holes 78c can be connected. For example, the thickness of the porous member 74 may be approximately equal to the thickness of the base 72, and the lower surface of the porous member 74 may be exposed at the second surface 72b of the base 72. In this case, the through holes 78c are formed only in the polishing layer 78, and the porous member 74 and the through holes 78c are connected at the interface between the base 72 and the polishing layer 78.

[0059] 4 shows a configuration example in which the porous member 74 is provided on the polishing pad 48, but the porous member can also be provided on the mount 46. Modified examples of the mount 46 and the polishing pad 48 will be described below.

[0060] Fig. 5(A) is a perspective view showing the upper surface side of the mount 46A, and Fig. 5(B) is a perspective view showing the lower surface side of the mount 46A. The mount 46A corresponds to a modified example of the mount 46 shown in Figs. 2(A) and 2(B).

[0061] The mount 46A includes a disk-shaped base 80. For example, the base 80 is made of a metal such as SUS (stainless steel), and includes a first surface (upper surface) 80a and a second surface (lower surface) 80b that are generally parallel to each other.

[0062] A cylindrical polishing liquid supply path (through hole) 80c is provided in the center of the first surface 80a side of the base 80, extending from the first surface 80a toward the second surface 80b side and penetrating the thickness direction of the base 80. The polishing liquid supply path 80c is formed so as to reach a porous member 82, which will be described later, and is connected to the porous member 82.

[0063] A plurality of cylindrical insertion holes (through holes) 80d are provided on the outer periphery of the base 80, penetrating the base 80 in the thickness direction from the first surface 80a to the second surface 80b. The plurality of insertion holes 80d are arranged at approximately equal intervals along the circumferential direction of the base 80. Although two insertion holes 80d are shown in Figures 5(A) and 5(B), there is no limit to the number of insertion holes 80d.

[0064] A cylindrical recess (groove) 80e is provided in the center of the second surface 80b side of the base 80. The recess 80e is formed from the second surface 80b toward the first surface 80a and is arranged concentrically with the base 80. A disk-shaped porous member 82 is fitted into the recess 80e. The porous member 82 is a member made of a porous material such as porous ceramics, porous resin, or porous metal, and includes pores that communicate in the thickness direction and radial direction. The porosity of the porous member 82 (the ratio of the volume of pores to the volume of the porous member 82) is, for example, 20% to 80%, or 30% to 70%.

[0065] For example, the porous member 82 is fixed to the bottom surface and side walls of the recess 80e with an adhesive. This connects the lower end of the polishing liquid supply path 80c (see FIG. 5(A)) to the porous member 82. The depth of the recess 80e and the thickness of the porous member 82 are approximately equal, and the second surface 80b of the base 80 and the surface (lower surface) 82a of the porous member 82 are disposed on approximately the same plane.

[0066] The first surface 80a side of the base 80 is connected to the spindle 44 (see FIG. 1). This connects the polishing liquid supply path 80c to the polishing liquid supply path 52 (see FIG. 1). The mount 46A may be the same member as the spindle 44, or may be a member independent of the spindle 44 that is detachable from the spindle 44. A bolt 50 (see FIG. 1) is inserted into the insertion hole 80d.

[0067] Fig. 6(A) is a perspective view showing the upper surface side of polishing pad 48A, and Fig. 6(B) is a perspective view showing the lower surface side of polishing pad 48A. Polishing pad 48A corresponds to a modified version of polishing pad 48 shown in Figs. 3(A) and 3(B). Polishing pad 48A includes a disk-shaped base 84 attached to mount 46A and a disk-shaped polishing layer 88 fixed to base 84.

[0068] For example, the base 84 is made of a metal such as SUS (stainless steel), and includes a first surface (upper surface) 84a and a second surface (lower surface) 84b that are generally parallel to each other. The base 84 is also provided with a plurality of cylindrical through-holes 84c that penetrate the base 84 in the thickness direction from the first surface 84a to the second surface 84b, and are provided throughout the base 84. For example, the plurality of through-holes 84c are arranged along a plurality of imaginary lines (12 in FIG. 6(A)) that are arranged radially in the radial direction of the base 84. However, there is no limit to the number and arrangement of the through-holes 84c.

[0069] The diameter of the base 84 is, for example, 300 mm or more and 500 mm or less. The through-hole 84c closest to the center of the base 84 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the center of the base 84. The through-hole 84c closest to the outer periphery of the base 84 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the outer periphery of the base 84.

[0070] In addition, an annular sealing member 86 is provided on the first surface 84a side of the base 84. For example, the sealing member 86 is an O-ring made of rubber, and is provided so as to surround the plurality of through-holes 84c in plan view. A lower end of the sealing member 86 is embedded in the first surface 84a of the base 84, and an upper end of the sealing member 86 is exposed from the base 84.

[0071] A plurality of cylindrical screw holes 84d are formed on the first surface 84a side of the outer periphery of the base 84, extending from the first surface 84a toward the second surface 84b. The screw holes 84d are provided in the same number as the insertion holes 80d (see FIGS. 5(A) and 5(B)) of the mount 46A, and are arranged at approximately equal intervals along the circumferential direction of the base 84. The tips of the bolts 50 (see FIG. 1) are inserted and screwed into the screw holes 84d.

[0072] A disk-shaped polishing layer 88 having approximately the same diameter as the base 84 is fixed to the second surface 84b side of the base 84. The polishing layer 88 includes a first surface (upper surface) 88a and a second surface (lower surface) 88b that are approximately parallel to each other. The material of the polishing layer 88, the particle size and material of the abrasive grains (fixed abrasive grains) contained in the polishing layer 88, etc. are the same as those of the polishing layer 78 (see FIGS. 3(A) and 3(B)).

[0073] A plurality of cylindrical through-holes 88c are provided throughout the polishing layer 88, penetrating the polishing layer 88 in the thickness direction from the first surface 88a to the second surface 88b. For example, the plurality of through-holes 88c are arranged along a plurality of (12 in FIG. 6(B)) imaginary lines arranged radially in the radial direction of the polishing layer 88. However, there is no limit to the number and arrangement of the through-holes 88c.

[0074] The diameter of the polishing layer 88 is, for example, 300 mm or more and 500 mm or less. The through-hole 88c closest to the center of the polishing layer 88 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the center of the polishing layer 88. The through-hole 88c closest to the outer periphery of the polishing layer 88 is provided, for example, in a region within 50 mm, preferably within 10 mm, from the outer periphery of the polishing layer 88.

[0075] The angle of the polishing layer 88 is adjusted so that the through holes 84c and 88c are connected (see FIG. 7). This forms a plurality of through holes that penetrate the polishing pad 48A in the thickness direction. The through holes 84c and 88c are also positioned so that they overlap with the porous member 74 when the polishing pad 48A is attached to the mount 46A (see FIG. 7).

[0076] FIG. 7 is a partial cross-sectional side view showing a polishing apparatus 2 that polishes a workpiece 11 with a polishing pad 48A attached to a mount 46A. When grinding a workpiece 11 with the polishing pad 48A, the polishing pad 48A is attached to the mount 46A. Specifically, first, the polishing pad 48A is positioned so that the second surface 80b of the base 80 contacts the first surface 84a of the base 84. At this time, the angle of the polishing pad 48A is adjusted so that the insertion hole 80d of the base 80 and the screw hole 84d of the base 84 are connected. Then, the bolt 50 is inserted into the insertion hole 80d and screwed into the screw hole 84d. This tightens the bolt 50, and the polishing pad 48A is fixed to the mount 46A.

[0077] When the polishing unit 40 is lowered by the Z-axis movement mechanism 28 (see FIG. 1) while rotating the chuck table 18 and the spindle 44, the second surface 88b of the rotating polishing layer 88 is pressed against the back surface 11b of the workpiece 11, polishing the back surface 11b of the workpiece 11. During polishing of the workpiece 11, a polishing liquid is supplied from the polishing liquid supply source 56 to the polishing liquid supply path 52 via the valve 54. The polishing liquid that flows from the polishing liquid supply path 52 into the polishing liquid supply path 80c is supplied to the through-holes 84c and 88c through the pores inside the porous member 82. As a result, the polishing liquid flows out from the lower ends of the multiple through-holes 88c and is supplied to the back surface 11b of the workpiece 11.

[0078] Linear grooves (not shown) connecting the lower ends of the plurality of through-holes 88c may be provided on the second surface 88b side of the polishing layer 88. In this case, the cleaning liquid supplied to the workpiece 11 is more likely to flow along the back surface 11b of the workpiece 11, and the polishing liquid is more likely to spread over the entire back surface 11b side of the workpiece 11.

[0079] When the mount 46A is used to polish the workpiece 11, the centrifugal force of the rotating mount 46A acts on the polishing liquid that has flowed from the polishing liquid supply path 80c into the porous member 82, causing the polishing liquid to flow and spread toward the outer edge of the porous member 82 through the pores inside the porous member 82. The polishing liquid then flows from the porous member 82 into each of the multiple through holes 84c, and is supplied to the workpiece 11 from the lower ends of the multiple through holes 88c. As a result, a sufficient amount of polishing liquid is supplied over a wide range from the center of the workpiece 11 to the outer edge.

[0080] Alternatively, a mount 46A (see FIGS. 5(A) and 5(B)) may be fixed to the spindle 44, and a polishing pad 48 (see FIGS. 3(A) and 3(B)) may be attached to the mount 46A. In this case, the porous member 82 of the mount 46A and the porous member 74 of the polishing pad 48 come into contact with each other, and the pores of the porous member 82 and the pores of the porous member 74 are connected to each other.

[0081] As described above, the polishing pad 48 according to this embodiment includes a porous member 74 to which the polishing liquid is supplied (see FIGS. 3A and 4). This allows the polishing liquid to flow from the center of the polishing pad 48 toward the outer periphery inside the polishing pad 48. Similarly, the mount 46A according to this embodiment includes a porous member 82 to which the polishing liquid is supplied (see FIGS. 5B and 7). This allows the polishing liquid to flow from the center of the mount 46A toward the outer periphery inside the mount 46A. As a result, the polishing liquid is more easily supplied not only to the center of the workpiece 11 but also to the outer periphery, thereby preventing a partial shortage of the polishing liquid.

[0082] The structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0083] 11 Workpiece 11a surface 11b Back side 13 Protective materials 2 Polishing equipment 4 Foundation 4a,4b opening 6a, 6b Cassette placement area (cassette placement table) 8a,8b cassette 10 First conveying mechanism 12 Operation panel 14 Position adjustment mechanism (alignment mechanism) 16 Second transport mechanism (loading arm) 18 Chuck table (holding table) 18a Holding surface 20 X-axis movement mechanism 22 Table Cover 24 Dustproof and water-resistant cover 26 Support structure 28 Z-axis movement mechanism 30 guide rail 32 Moving Plate 34 Ball screw 36 Pulse motor 38 Support member 40 Polishing Unit 42 Housing 44 Spindle 46,46A Mount 48,48A Polishing Pad 50 volts 52 Polishing liquid supply path 54 Valve 56 Polishing liquid supply source 58 Third transport mechanism (unloading arm) 60 Cleaning Unit 62 Control unit (control unit, control device) 70 Foundations 70a 1st side (top side) 70b 2nd side (bottom side) 70c Polishing liquid supply path (through hole) 70d Insertion hole (through hole) 72 Foundation 72a 1st side (top side) 72b 2nd side (bottom side) 72c Recess (groove) 72d screw hole 74 ポーラスComponents 74a Surface (top) 76 シール parts 78 grinding layers 78a Page 1 (top) 78b Page 2 (bottom) 78c Through Hole 80 abutment 80a Page 1 (top) 80b, Page 2 (bottom) 80c Grinding Fluid Supply Channel (Through Hole) 80d Insertion Hole (Through Hole) 80e concave part (groove) 82 ポーラスComponents 82a Surface (bottom) 84 abutment 84a Page 1 (top) 84b Page 2 (bottom) 84c Through Hole 84d ねじhole 86 シール parts 88 grinding layers 88a Page 1 (top) 88b Page 2 (bottom) 88c Through Hole

Claims

1. A mount provided in a polishing apparatus for polishing a workpiece and on which a polishing pad is attached, comprising: a disk-shaped base including a first surface and a second surface and having a recess on the second surface side; a porous member provided in the recess of the base; a polishing liquid supply path extending from the first surface of the base to the porous member; The mount is characterized in that the polishing liquid supplied to the polishing liquid supply path is supplied to the polishing pad attached to the second surface side of the base via the porous member.

2. 2. The mount according to claim 1, wherein the polishing liquid is supplied from the porous member to a plurality of through holes that penetrate the polishing pad.

3. A polishing apparatus for polishing a workpiece, comprising: a chuck table for holding the workpiece; a polishing unit that polishes the workpiece held by the chuck table, The polishing unit comprises: A spindle and a mount fixed to the tip of the spindle and on which a polishing pad is attached; The mount comprises a disk-shaped base including a first surface and a second surface and having a recess on the second surface side, a porous member provided in the recess of the base, and a polishing liquid supply path extending from the first surface of the base to the porous member, and the polishing liquid supplied to the polishing liquid supply path is supplied to the polishing pad attached to the second surface side of the base via the porous member.

4. 4. The polishing apparatus according to claim 3, wherein the polishing liquid is supplied from the porous member to a plurality of through holes that penetrate the polishing pad.

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