JP2016159416A - Polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad with high versatility allowing the specification to be easily changed.SOLUTION: A polishing pad (1) is mounted on a disk-like base (40) connected to a rotary shaft (38) of a polishing device (2) for polishing a plate-like object (21). The polishing pad includes: a substrate member (3) mounted on the base of the polishing device; and a plurality of annular members (13) of different diameters which are respectively fixed to the substrate member and have respective polishing clothes (17) adhered to the opposite sides of the sides fixed to the substrate member. In the partial annular members, polishing clothes which are types different from the other partial annular members are adhered. The plurality of annular members are respectively and detachably fixed to the substrate member so that an inner peripheral surface (13a) of the outside annular member of two adjacent annular members is brought into contact with an outer peripheral surface (13b) of the inside annular member so as to concentrically dispose all the annular members.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polishing pad used when polishing a plate-like object such as a wafer.

  In a manufacturing process of a semiconductor device typified by IC, LSI, etc., a semiconductor wafer made of a semiconductor material such as silicon may be planarized by chemical mechanical polishing (CMP) or the like. In polishing techniques such as CMP, a polishing apparatus equipped with a polishing pad (for example, see Patent Document 1) made of a nonwoven fabric or a polymer foam is generally used.

  In recent years, semiconductor wafers have been increased in size in order to increase the productivity of semiconductor devices. On the other hand, when the semiconductor wafer is enlarged, the entire surface of the semiconductor wafer cannot be uniformly polished with the conventional polishing pad. Therefore, a polishing pad is proposed in which the hardness of the polishing layer varies from region to region (see, for example, Patent Document 2).

JP 2004-123975 A JP 2006-231464 A

  If the above-described polishing pad is used, the entire surface of the enlarged semiconductor wafer can be uniformly polished to improve the flatness. However, this polishing pad is formed by integrally fixing a plurality of polishing layers having different hardness. For example, when it is desired to change the specification of the polishing pad according to the result of polishing, another polishing pad is newly added. Had to be manufactured.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a highly versatile polishing pad whose specifications can be easily changed.

  According to the present invention, a polishing pad attached to a disk-like base connected to a rotating shaft of a polishing apparatus for polishing a plate-like object, a base member attached to the base of the polishing apparatus; A plurality of annular members having different diameters, each of which is fixed to the base member and having a polishing cloth bonded to the side opposite to the side fixed to the base member. A polishing cloth of a different type from that of the other part of the annular member is bonded, and the plurality of annular members are arranged on the outer peripheral surface of the annular member inside the two adjacent annular members. A polishing pad is provided that is detachably fixed to the base member such that all the annular members are arranged concentrically by contacting the inner peripheral surface of the annular member.

  In the present invention, each of the plurality of annular members preferably has a female screw portion and is fixed to the base member using a male screw.

  A polishing pad according to the present invention includes a base member mounted on a base and a plurality of annular members having different diameters to which a polishing cloth is bonded, and the plurality of annular members are attached to and detached from the base member, respectively. Since it is fixed freely, the specification of the polishing pad can be easily changed by replacing an arbitrary annular member with another annular member having a different type of polishing cloth. Thus, according to the present invention, it is possible to provide a highly versatile polishing pad whose specifications can be easily changed.

It is a perspective view which shows typically the structural example of a polishing pad. It is a disassembled perspective view which shows the structural example of a polishing pad typically. It is a perspective view which shows typically the structural example of the disk shaped member which comprises a polishing pad. It is a perspective view showing typically an example of composition of an annular member which constitutes a polishing pad. It is the figure which looked at the polishing pad from the polishing cloth side. It is a perspective view showing typically an example of composition of a polisher in which a polishing pad is used. It is a figure which shows typically a mode that a plate-shaped object is grind | polished. It is a figure which shows the positional relationship of a plate-shaped object and a polishing pad.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically illustrating a configuration example of a polishing pad according to the present embodiment, and FIG. 2 is an exploded perspective view schematically illustrating a configuration example of a polishing pad. As shown in FIGS. 1 and 2, the polishing pad 1 includes a base member (platen) 3 having a predetermined rigidity.

  The base member 3 is formed in a disk shape using, for example, a resin such as polyether ether ketone (PEEK), and has a substantially flat first surface 3a and second surface 3b. Yes. The first surface 3a side of the base member 3 is attached to a disc-shaped mounter (base) 40 provided in a polishing apparatus 2 (see FIG. 6) described later.

  On the other hand, a disc-like member 5 formed in a circular shape in plan view is fixed to the central region of the base member 3 on the second surface 3b side. FIG. 3 is a perspective view schematically showing a configuration example of the disk-like member 5. As shown in FIG. 3, the disk-shaped member 5 includes a disk-shaped plate 7.

  The plate 7 is formed with a diameter smaller than that of the base member 3 using, for example, the same resin as that of the base member 3, and has a substantially flat first surface 7a and second surface 7b. On the first surface 7 a side of the plate 7, a plurality (eight in this embodiment) of female screw portions 7 c in which screws (thread grooves) are cut on the inner peripheral surface of the recess are formed. Further, a through hole 7d serving as a flow path for the polishing liquid is formed at the center of the plate 7.

  On the second surface 7 b side of the plate 7, a polishing cloth 9 formed in a disk shape similar to the plate 7 is bonded. The polishing cloth 9 is adhered to the plate 7 using, for example, an adhesive tape, and contacts the target plate-like object 21 (see FIG. 7) during polishing. Note that the polishing pad 9 may be bonded to the plate 7 using an arbitrary adhesive. Further, a through hole 9a corresponding to the through hole 7d of the plate 7 is formed at the center of the polishing pad 9 (see FIG. 5).

  As the polishing cloth 9, either a non-woven fabric type or a polymer foam type can be used. For example, when polishing a plate-like material made of a semiconductor material such as silicon, a non-woven type SUBA (registered trademark) series, a polymer foam type IC1000 (registered trademark) made of foamed polyurethane, etc., in a single layer, Alternatively, two or more layers may be used.

  In addition, when the polishing pad 9 has a laminated structure (typically, a laminated structure of SUBA (registered trademark) 400 and IC1000 (registered trademark)), the polishing cloth 9 is easily bent. Even if a cushioning material such as rubber is not provided, the plate-like object 21 and the polishing pad 9 can be properly brought into contact with each other.

  As shown in FIGS. 1 and 2, a plurality of base members 3 penetrating from the first surface 3 a side to the second surface 3 b side at positions corresponding to the female screw portions 7 c of the plate 7 in the base member 3 (this embodiment) Eight through holes 3c are formed. By tightening the male screw 11 into the female screw portion 7 c of the plate 7 through the through hole 3 c, the disk-like member 5 is detachably fixed to the second surface 3 b side of the base member 3.

  A through hole 3 d corresponding to the through hole 7 d of the plate 7 is formed in the center of the base member 3. The polishing liquid supplied from the mounter 40 side is guided to the upper surface of the plate-like object 21 through the through holes 3d, 7d, 9a.

  Further, on the second surface 3 b side of the base member 3, a plurality of annular members 13 with different diameters formed in an annular shape in plan view are fixed concentrically surrounding the disk-like member 5. FIG. 4 is a perspective view schematically showing a configuration example of the annular member 13. As shown in FIG. 4, the annular member 13 includes an annular plate 15.

  The plate 15 is formed with a diameter larger than that of the plate 7 of the disk-like member 5 using, for example, the same resin as that of the base member 3, and has a substantially flat first surface 15a and second surface 15b. Yes. On the first surface 15 a side of the plate 15, a plurality (eight in this embodiment) of female screw portions 15 c in which screws (thread grooves) are cut on the inner peripheral surface of the recess are formed.

  On the second surface 15 b side of the plate 15, a polishing cloth 17 formed in an annular shape similar to the plate 15 is bonded. The polishing cloth 17 is bonded to the plate 15 using, for example, an adhesive tape, and comes into contact with the plate-like object 21 during polishing. Note that the polishing cloth 17 may be bonded to the plate 15 using an arbitrary adhesive.

  The material and the like of the polishing cloth 17 are the same as the material and the like of the polishing cloth 9 of the disc-like member 5. However, at least one of the disk-shaped member 5 and the plurality of annular members 15 is bonded with a different type of polishing cloth from any of the other members. That is, the polishing pad 1 includes two or more types of different polishing cloths. Here, “different types” means that the features contributing to the polishing ability such as material and hardness are different.

  As shown in FIGS. 1 and 2, a plurality of base members 3 that penetrate the base member 3 from the first surface 3a side to the second surface 3b side at positions corresponding to the female screw portions 15c of the plate 15 in the base member 3 (this embodiment) Eight through holes 3e are formed. By tightening the male screw 19 into the female screw portion 15c of the plate 15 through the through hole 3e, the annular member 13 is fixed to the second surface 3b side of the base member 3.

  FIG. 5 is a view of the polishing pad 1 viewed from the polishing cloths 9 and 17 side. The diameter of the disk-shaped member 5 is equal to the inner diameter of the adjacent annular member 13, and when the disk-shaped member 5 and the plurality of annular members 13 are fixed to the base member 3 as described above, as shown in FIG. The outer peripheral surface 5 a of the disk-shaped member 5 is in contact with the inner peripheral surface 13 a of the adjacent annular member 13.

  Further, in the two adjacent annular members 13, the outer diameter of the inner annular member 13 is equal to the inner diameter of the outer annular member 13, and as shown in FIG. The inner peripheral surface 13a of the outer annular member 13 is in contact with 13b. That is, the disc-like member 5 and the plurality of annular members 13 are disposed concentrically (annular ring shape) on the polishing pad 1 with no gap.

  In the polishing pad 1 according to the present embodiment configured as described above, since the polishing cloths 9 and 17 can be selected for each of the disk-shaped member 5 or the annular member 13, the polishing pad 1 satisfying a desired specification can be easily formed. As an example of the specification, there is one in which different types of polishing cloths 9 and 17 are adopted in each of the four regions A1, A2, A3, and A4 as shown in FIG. Of course, the specification of the polishing pad 1 is not limited to this, and can be arbitrarily set and changed.

  Further, in the polishing pad 1 according to the present embodiment, the disc-like member 5 and the annular member 13 are detachably fixed to the base member 3 by male screws 11 and 19. Therefore, the specification of the polishing pad 1 can be quickly changed by rearranging the disk-shaped member 5 and the annular member 13 according to the result of polishing.

  In addition, due to the properties of the polishing pad 1 according to the present embodiment, the flatness on the polishing cloths 9 and 17 side may not be sufficiently ensured only by fixing the disk-like member 5 and the annular member 13 to the base member 3. In such a case, it is preferable that the polishing pad 9 and 17 side of the polishing pad 1 is dressed and flattened before the plate-like object 21 is polished.

  Next, an example of a polishing apparatus in which the polishing pad 1 according to the present embodiment is used will be described. FIG. 6 is a perspective view schematically showing a configuration example of a polishing apparatus in which the polishing pad 1 is used. As shown in FIG. 4, the polishing apparatus 2 includes a base 4 that supports each structure.

  An opening 4 a is formed on the front end side of the upper surface of the base 4, and a transport mechanism 6 for transporting the plate-like object 21 to be polished is provided in the opening 4 a. Further, cassettes 8a and 8b capable of accommodating the plate-like object 21 are placed in a region further forward of the opening 4a. The plate-like object 21 is, for example, a semiconductor wafer, a resin substrate, a ceramic substrate or the like formed in a disk shape. However, the plate-like object 21 is not necessarily limited to these.

  An alignment mechanism 10 for aligning the plate-like object 21 is provided behind the placement area on which the cassette 8a is placed and the opening 4a. The alignment mechanism 10 performs alignment of the plate-like object 21 that is conveyed by the conveyance mechanism 6 from the cassette 8a and placed on the alignment mechanism 10, for example.

  Behind the alignment mechanism 10 is provided a carry-in mechanism 12 that can rotate by sucking and holding the plate-like object 21. An opening 4 b is formed behind the carry-in mechanism 12. In this opening 4b, an X-axis moving table 14, an X-axis moving mechanism (not shown) for moving the X-axis moving table 14 in the X-axis direction (front-rear direction), and a dustproof and splash-proof cover 16 that covers the X-axis moving mechanism. Is provided.

  The X-axis movement mechanism includes a pair of X-axis guide rails (not shown) parallel to the X-axis direction, and an X-axis movement table 14 is slidably installed on the X-axis guide rails. A nut portion (not shown) is provided on the lower surface side of the X-axis moving table 14, and an X-axis ball screw (not shown) parallel to the X-axis guide rail is screwed to the nut portion.

  An X-axis pulse motor (not shown) is connected to one end of the X-axis ball screw. By rotating the X-axis ball screw with the X-axis pulse motor, the X-axis moving table 14 moves in the X-axis direction along the X-axis guide rail.

  A chuck table 18 that sucks and holds the plate-like object 21 is provided on the X-axis moving table 14. The chuck table 18 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis extending in the vertical direction (Z-axis direction).

  The upper surface of the chuck table 18 is a holding surface 18 a that holds the plate-like object 21 by suction. The holding surface 18 a is connected to a suction source (not shown) through a flow path (not shown) formed inside the chuck table 18. The plate-like object 21 carried in by the carry-in mechanism 12 is sucked and held on the chuck table 18 by the negative pressure of the suction source acting on the holding surface 18a.

  A columnar support structure 20 stands substantially vertically behind the opening 4b. A Z-axis moving mechanism 22 is provided on the front surface side of the support structure 20. The Z-axis moving mechanism 22 includes a pair of Z-axis guide rails 24 that are arranged on the front surface of the support structure 20 and are parallel to the Z-axis direction. A Z-axis moving plate 26 is slidably installed on the Z-axis guide rail 24.

  A nut portion (not shown) is provided on the rear surface side (back surface side) of the Z-axis moving plate 26, and a Z-axis ball screw 28 parallel to the Z-axis guide rail 24 is screwed into the nut portion. Yes. A Z-axis pulse motor 30 is connected to one end of the Z-axis ball screw 28. By rotating the Z-axis ball screw 28 by the Z-axis pulse motor 30, the Z-axis moving plate 26 moves in the Z-axis direction along the Z-axis guide rail 24.

  A support tool 32 is fixed to the front surface (surface) of the Z-axis moving plate 26. A polishing unit (polishing means) 34 for polishing the plate-like object 21 is supported on the support 32. The polishing unit 34 includes a spindle housing 36 fixed to the support 32. The spindle housing 36 accommodates a spindle (rotating shaft) 38 that constitutes a rotating shaft substantially parallel to the Z-axis direction.

  A disc-shaped mounter 40 is provided at the lower end of the spindle. The lower surface of the mounter 40 is a holding surface that sucks and holds the base member 3 side of the polishing pad 1. This holding surface is connected to a suction source (not shown) through a flow path (not shown) formed in the mounter 40. The polishing pad 1 is sucked and held by the mounter 40 with the negative pressure of the suction source acting on the holding surface. The polishing pad 1 may be fixed to the mounter 40 using a fixing tool such as a screw.

  FIG. 7 is a side view schematically showing how the plate-like object 21 is polished. As shown in FIG. 7, a polishing liquid supply source 44 that supplies a polishing liquid such as slurry is connected to the spindle 38 via a pipe 42. Supply paths 38a and 40a are respectively formed inside the spindle 38 and the mounter 40, and the polishing liquid from the polishing liquid supply source 44 passes through the through hole 3d of the polishing pad 1 through the pipe 42, the supply paths 38a and 40a, and the like. , 7d, 9a.

  As shown in FIG. 7, while the plate-like object 21 is sucked and held by the chuck table 18, the chuck table 18 and the polishing pad 1 are rotated with each other, and the polishing liquid is supplied to the upper surface of the plate-like object 21. If the polishing pad 1 is brought into contact, the plate-like object 21 can be polished. This polishing is performed, for example, while measuring the thickness of the plate-like object 21 in real time with a non-contact type thickness measuring device 46 adjacent to the polishing unit 34.

  FIG. 8 is a diagram schematically showing the positional relationship between the polishing pad 1 and the plate-like object 21. As shown in FIGS. 7 and 8, the rotation axis of the polishing pad 1 and the rotation axis of the plate-like object 21 (chuck table 18) do not coincide with each other, and the center portion and the outer peripheral portion are rotated. The speed is also different. Thereby, the contact frequency between the polishing pad 1 and the plate-like object 21 is not equal over the entire surface of the plate-like object 21.

  Therefore, for example, when a polishing pad composed of a single polishing cloth is used, polishing spots are likely to occur on the plate-like material. Specifically, when the rotational speed of the plate-like object is larger than the rotational speed of the polishing pad, or when the rotational speed of the polishing pad is larger than the rotational speed of the workpiece, polishing of the outer peripheral portion is easy to proceed, The plate-like product after polishing becomes convex.

  On the other hand, when the rotational speed of the plate-like object is equal to the rotational speed of the polishing pad, there is no speed difference between the polishing pad and the plate-like object in a part of the region, and polishing is difficult to proceed. In particular, since polishing is difficult to proceed at the outer peripheral portion, the plate-like object after polishing becomes concave.

  On the other hand, in the polishing pad 1 according to this embodiment, the polishing rate can be set for each region, so that the plate-like object 21 can be flattened by reducing the above-mentioned polishing spots. Further, the amount of wear of the polishing pad 1 varies from region to region due to the frequency of contact with the plate-like object 21, but in the polishing pad 1 according to the present embodiment, the polishing cloths 9 and 17 ( The disc-like member 5 and the annular member 13) can be replaced as appropriate.

  In addition, the rotation speeds of the chuck table 18 and the polishing pad 1 are each controlled to 100 rpm to 800 rpm, preferably 200 rpm to 500 rpm. However, if the rotation of the chuck table 18 and the rotation of the polishing pad 1 are synchronized, the polishing of the plate-like object 21 is difficult to proceed as described above. Therefore, the rotation speed of the chuck table 18 and the rotation speed of the polishing pad 1 are slightly different. Are preferably different.

  In the vicinity of the polishing unit 34, a first cleaning nozzle 48 for cleaning the polishing pad 9 and 17 side of the polishing pad 1 and a second cleaning nozzle 50 for cleaning the holding surface 18a of the chuck table 18 are provided. The polishing pad 1 and the chuck table 18 are kept clean by the first cleaning nozzle 48 and the second cleaning nozzle 50.

  At a position adjacent to the carry-in mechanism 12, a carry-out mechanism 52 that is capable of rotating by sucking and holding the polished plate-like object 21 is provided. A cleaning unit 54 for cleaning the polished plate-like object 21 is provided in front of the carry-out mechanism 52 and behind the opening 4a. The plate-like object 21 cleaned by the cleaning unit 54 is transported by the transport mechanism 6 and accommodated in, for example, the cassette 8b.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the polishing apparatus 2 that can be used for CMP or the like is illustrated, but the polishing pad according to the present invention can also be used for dry polishing or the like that does not use a polishing liquid.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

1 Polishing pad 3 Base material (platen)
3a 1st surface 3b 2nd surface 3c, 3d, 3e Through-hole 5 Disc-shaped member 5a Outer peripheral surface 7 Plate 7a 1st surface 7b 2nd surface 7c Female screw part 7d Through-hole 9 Polishing cloth 9a Through-hole 11 Male screw 13 Annular Member 13a Inner peripheral surface 13b Outer peripheral surface 15 Plate 15a First surface 15b Second surface 15c Female screw part 17 Polishing cloth 19 Male screw 21 Plate-like object 2 Polishing device 4 Base 4a, 4b Opening 6 Transport mechanism 8a, 8b Cassette 10 Positioning mechanism 12 Loading mechanism 14 X-axis moving table 16 Dust-proof / splash-proof cover 18 Chuck table 18a Holding surface 20 Support structure 22 Z-axis moving mechanism 24 Z-axis guide rail 26 Z-axis moving plate 28 Z-axis ball screw 30 Z-axis pulse motor 32 Support tool 34 Polishing unit (polishing means)
36 Spindle housing 38 Spindle (Rotating shaft)
38a Supply path 40 Mounter (base)
40a Supply path 42 Pipe 44 Polishing liquid supply source 46 Thickness measuring device 48 First cleaning nozzle 50 Second cleaning nozzle 52 Unloading mechanism 54 Cleaning unit

Claims (2)

A polishing pad attached to a disk-shaped base connected to a rotating shaft of a polishing apparatus for polishing a plate-like object,
A base member mounted on the base of the polishing apparatus;
A plurality of annular members having different diameters, each fixed to the base member, and each having an abrasive cloth bonded to the side opposite to the side fixed to the base member;
A part of the annular member is bonded with a different kind of polishing cloth from the other part of the annular member,
The plurality of annular members are arranged concentrically with the outer peripheral surface of the annular member inside the two adjacent annular members contacting the inner peripheral surface of the outer annular member. As described above, the polishing pad is detachably fixed to the base member.   The polishing pad according to claim 1, wherein each of the plurality of annular members has a female screw portion and is fixed to the base member using a male screw.

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