JP2010253646A - Polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing pad capable of reducing or avoiding peeling of an opening part of the polishing pad generated by rotation and moving of a wafer carrier in a double-side polishing machine. <P>SOLUTION: Peeling of the opening part 110 provided in the polishing pad 40 of a surface plate 20 is reduced by providing an inclination part 170 in a polishing surface 150 side part of the opening part 110. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing pad used in a double-side polishing machine.

  In recent years, in the polishing of silicon wafers, a double-sided polishing machine is often used instead of a conventional single-sided polishing machine from the viewpoint of improving productivity and polishing accuracy.

  FIG. 4 is a diagram showing a typical double-side polishing machine 1. 4A is an external view of the double-side polishing machine 1, and FIG. 4B is a cross-sectional view taken along a cutting plane line AB in FIG. 4A.

  The double-side polishing machine 1 has an upper surface plate 2 to which an upper surface plate polishing pad 4 is bonded and a lower surface plate 3 to which a lower surface plate polishing pad 5 is bonded. 3 has a plurality of wafer carriers 6 (see FIG. 4B) for holding an object to be polished. The upper surface plate 2 and the lower surface plate 3 are doughnut-shaped, and the wafer carrier rotating pins 7 for forcibly rotating the plurality of wafer carriers 6 are provided on the inner and outer circumferences of the surface plates 2 and 3. 8 (see FIG. 4B for the rotation pin 7) or a gear (not shown) is arranged. Accordingly, the plurality of wafer carriers 6 are set between the inner peripheral side wafer carrier rotating pins 7 and the outer peripheral side wafer carrier rotating pins 8, and are in the shape of doughnuts like the two surface plates 2 and 3. It is in a state of being sandwiched between the board polishing pad 4 and the lower surface plate polishing pad 5.

  Each of the five wafer carriers 6 shown here is provided with a rotation gear (not shown) on the outer periphery thereof. Each of the wafer carriers 6 is provided with an object storage portion 9 which is a through hole portion for storing an object to be polished, and a slurry passage hole 10 through which polishing slurry used at the time of polishing is passed.

  In actual polishing, each wafer carrier 6 is forcibly rotated by engaging the inner peripheral side wafer carrier rotating pin 7 and the outer peripheral side wafer carrier rotating pin 8 with the rotating gear portion. Further, the upper surface plate 2 and the lower surface plate 3 also rotate independently. Accordingly, each wafer carrier 6 moves between the upper and lower polishing pads 4 and 5 while rotating.

FIG. 5 is a diagram for explaining the behavior near the opening 11 during conventional polishing.
The upper surface plate 2 of the double-side polishing machine 1 mainly used for polishing a silicon wafer or the like has a polishing slurry used for polishing and a liquid and / or for detachment of an object to be polished after polishing. A through hole 14 for supplying gas is provided. Therefore, the upper surface plate polishing pad 4 used in the double-side polishing machine 1 also needs to be provided with an opening 11 having a size corresponding to the through hole 14 at an opposing position.

  In actual polishing, when the wafer carrier 6 moves, the wafer carrier 6 passes over the opening 11.

  In such polishing, as shown in FIG. 5A, the upper surface plate polishing pad 4 is sandwiched between the wafer carrier 6 and the upper surface plate 2, and a certain pressure required for polishing is applied. , Compressive deformation by a certain amount. In other words, the wafer carrier 6 moves while being slightly submerged on the upper surface plate polishing pad 4 by compressing the upper surface plate polishing pad 4.

  When the wafer carrier 6 reaches the opening 11 provided in the upper surface plate polishing pad 4, as shown in FIG. 5B, before and after the traveling direction of the wafer carrier 6, that is, before and after the opening 11. A level difference occurs in the polishing pad.

  Next, when the wafer carrier 6 moves in the traveling direction of the arrow, the end surface of the wafer carrier 6 comes into contact with the inner wall of the opening 11 and pushes the inner wall of the opening 11 in the traveling direction. Due to such contact, as shown in FIG. 5C, the inner wall of the opening 11 on the traveling side of the opening 11 is partially deformed, and the adhesive layer provided on the back surface of the upper surface plate 2 and the upper surface plate polishing pad 4. The stress concentrates on the interface with 13. Due to the concentration of the stress, as shown in FIG. 5 (d), peeling occurs at the interface between the upper surface plate 2 and the adhesive layer 13 provided on the back surface of the upper surface plate polishing pad 4.

  When the peeling occurs, the polishing slurry enters the peeling portion, so that it becomes difficult to re-adhere the peeling portion. Therefore, when the behavior in the vicinity of the opening 11 is repeated during polishing, the peeling generated in the opening 11 progresses.

  In order to solve such a problem, a technique for providing a taper at a corner of a work carrier (corresponding to the wafer carrier 6) has been proposed (for example, see Patent Document 1).

  In addition, in a polishing pad, a grid-like groove may be provided on a polishing surface which is a surface in contact with a wafer carrier in order to uniformly supply a polishing slurry. Further, an adhesive material for attaching the polishing pad to the surface plate is attached to the opposite side of the polishing surface, that is, the back surface of the polishing pad.

JP 2007-331036 A

  However, even when the wafer carrier described in Patent Document 1 is used, as described above, when the end of the wafer carrier reaches the opening, as shown in FIG. Since there is a step in the polishing pad before and after the direction of movement of the wafer carrier, it cannot be avoided that the end surface of the wafer carrier contacts the inner wall of the opening beyond the tapered portion, and peeling occurs in the same manner as the mechanism described above. .

  In addition, when an extreme taper is provided at the corner of the wafer carrier, a temporary effect may be obtained, but the effect is not sustained because the wafer carrier is worn by polishing. That is, when the number of polishing increases, the taper decreases or disappears, and the expected effect is not produced. Furthermore, the extreme taper reduces the rotation gear on the outer periphery of the wafer carrier, which may cause new problems such as damage during polishing.

  As described above, depending on the invention of Patent Document 1, peeling from the opening cannot be completely prevented, and a solution to the problem has been desired.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a polishing pad capable of reducing or avoiding peeling of an opening caused by rotation and movement of a wafer carrier in a double-side polishing machine. To do.

  In order to achieve the above object, a polishing pad according to the present invention is a polishing pad provided on at least one surface plate of a double-side polishing machine, and is provided on a plurality of surface plates that supply liquid and / or gas. A plurality of openings are provided in the polishing pad at a position opposite to the openings, and inclined portions are provided at corners formed by a polishing surface of the polishing pad and an inner surface of the opening.

  The polishing pad according to the present invention is a polishing pad provided on at least one surface plate of a double-side polishing machine, and faces a plurality of openings provided in one surface plate that supplies liquid and / or gas. A plurality of openings are provided in the polishing pad at a position, and an inclined portion having a certain angle is provided at a corner portion constituted by a polishing surface of the polishing pad and an inner surface of the opening.

  The polishing pad according to the present invention is characterized in that an angle of the inclined portion is 10 ° to 85 °.

  The polishing pad according to the present invention is characterized in that the width of the inclined portion is 0.1 mm to 3 mm.

  According to the present invention, in the double-side polishing machine, peeling of the polishing pad opening caused by the rotation and movement of the wafer carrier can be reduced or avoided.

  In addition, by avoiding the peeling, it is possible to avoid problems such as a decrease in uniformity due to peeling of the polishing pad and scratching during polishing, and to obtain a good surface to be polished.

It is a figure which shows an example of the opening part of the polishing pad which concerns on embodiment of this invention. It is a figure which shows the thickness of the inclination part which concerns on embodiment of this invention. It is a figure explaining the behavior of the opening part vicinity in grinding | polishing using the polishing pad which concerns on embodiment of this invention. It is a figure which shows a typical double-side polisher. It is a figure explaining the behavior near the opening part during grinding in the prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, since the structure regarding a double-side polisher is the same as what was shown in FIG. 4, the description shall be abbreviate | omitted.

  FIG. 1 is an enlarged view of an opening of an example of an opening of a polishing pad according to an embodiment of the present invention.

  In FIG. 1, even in this embodiment, the upper surface plate 20 of a double-side polishing machine used when polishing a silicon wafer or the like is used for polishing slurry used at the time of polishing and removal of an object to be polished after polishing. For separation, a through hole 140 for supplying liquid and / or gas is provided. Also in the upper surface plate polishing pad 40 used in the double-side polishing machine, an opening 110 having a size corresponding to the through hole 140 is provided at a position facing the through hole 140 so as to communicate with the through hole 140. .

  The upper surface plate polishing pad 40 includes a polishing pad main body 120 and an adhesive layer 130. The adhesive layer is not an essential component, and the polishing pad of the present invention may be only the polishing pad main body.

  The opening 110 is provided with an inclined portion 170 having a conical shape at the corner of the polishing pad main body 120 constituted by the polishing surface 150 of the upper surface plate polishing pad 40 and the inner surface of the opening 110. Yes.

  Here, it is preferable that the inclined portion 170 has a certain angle θ (an angle formed between the polishing surface 150 and the inclined surface of the inclined portion 170) for ease of processing. However, the inclined portion 170 has an inclination having the certain angle θ. As a reference, it may be uneven in the vertical direction.

  The angle θ is appropriately selected according to the thickness of the upper surface plate polishing pad 40 and the load during polishing, but is preferably 10 ° to 85 ° under general polishing conditions. If the angle θ is less than 10 ° or exceeds 85 °, the corner of the wafer carrier 60 is likely to come into contact with the inner wall of the opening, which is not preferable.

  In addition, about the connection part of the said inclined part 170 and the grinding | polishing surface 150 of the upper surface plate polishing pad 40 and / or the inner wall of the opening part 110, you may give R process to the boundary part. By such processing, the effect of the present invention becomes more remarkable.

FIG. 2 is a diagram illustrating the slope width W of the slope 170 according to the embodiment of the present invention.
The inclined portion width W according to the embodiment of the present invention is appropriately selected depending on the load and angle θ during polishing, but under general polishing conditions, it is 50 to 100% of the thickness of the polishing pad body 120. Preferably there is. As shown in FIG. 2A, when the inclined portion width W is 100% with respect to the thickness of the polishing pad main body 120, the effect of the present invention is maximized. When the angle θ is reduced, the strength of the polishing pad main body 120 near the inner wall polishing surface side end 160 of the opening 110 may be reduced, and the portion may be broken.

  However, when the width W of the inclined portion 170 is less than 50% of the thickness of the polishing pad main body 120, when the inclined portion 170 is worn due to the progress of polishing, the same as the conventional polishing pad shown in FIG. This is not preferable because

  The opening 110 of the polishing pad main body 120 is processed by a general method such as a punch or a drilling machine. In the processing of the inclined portion 170 according to the embodiment of the present invention, any method can be used, but the processing can be performed by, for example, a router, an end mill, a laser, or a knife.

  FIG. 3 is a diagram for explaining the behavior near the opening 110 in polishing using the polishing pad 40 according to the embodiment of the present invention.

  As shown in FIG. 3A, when the end of the wafer carrier 60 approaches the opening 110, the upper surface plate polishing pad 40 of the upper surface plate 20 is slightly sunk due to elastic deformation.

  Next, as shown in FIG. 3B, the wafer carrier 60 advances and the end of the wafer carrier 60 advances to the opening 110. In the upper surface plate polishing pad 40 according to the embodiment of the present invention, Due to the inclined portion 170 provided in the polishing pad main body 120 of the opening 110, no step is generated in the upper surface plate polishing pad 40 before and after the traveling direction, that is, before and after the opening 110.

  When the wafer carrier 60 further advances, as shown in FIG. 3C, the end portion of the wafer carrier 60 comes into contact with the inclined portion 170, but the stress is dispersed by the inclined surface, so that the upper surface plate is used. The polishing pad 40 hardly deforms.

Therefore, since unnecessary stress does not occur in the opening 110, the inner wall of the opening 110 is not partially lifted, and the upper surface plate 20 and the upper surface plate polishing pad 40, which have conventionally been problematic, No peeling occurs with the adhesive layer 130 provided on the back surface of the film. In the embodiment, the present invention is applied to the upper surface plate polishing pad 40 on the upper surface plate 20 side. However, when the double-side polishing machine supplies the polishing slurry from below, the lower surface plate side You may apply to the polishing pad for lower surface plates.
This will be described in more detail with reference to an example using an actually manufactured polishing pad.

  A polishing pad (product name: MH-S15A) manufactured by Nitta Haas Co., Ltd. was used as the polishing pad for the upper surface plate and the polishing pad for the lower surface plate. These polishing pad openings 110 have a diameter of 10 mm, a polishing pad provided with an inclined portion 170 having an inclined portion angle θ of 45 ° and an inclined portion width W of 65% of the thickness of the polishing pad main body 120 is prepared. did.

(Comparative example)
A polishing pad similar to that of Example 1 was prepared except that the inclined portion was not provided on the polishing surface side of the opening.

  A polishing test was performed using the polishing pad, and the number of openings where peeling occurred was compared. The polishing test was performed under the following conditions.

<Experimental conditions>
Polishing machine: Poli500 (G & P Technology)
Slurry: NP6220 (made by Nitta Haas Co., Ltd.)
Lower platen rotation speed: 115rpm
Upper platen rotation speed: 100rpm
Load: 300 gf / cm2
Slurry flow rate: 300 ml / min.
Polishing time: 30 min.
Polishing pad diameter: 200mm
Polishing pad thickness: 1.54mm
Slope width: 1.00mm
Number of openings: 10
Number of openings peeled = Example 0: Comparative example 9
Number of openings not peeled = Example 10: Comparative Example 1

  As described above, in the polishing pad of the comparative example, peeling occurred in most of the openings, but in the polishing pad of the example, the number of openings to be peeled clearly decreased as compared with the comparative example.

  Further, in the comparative example, uneven wear of the polishing pad was confirmed in the vicinity of the peeled opening. It is presumed that it was caused by the deformation of the polishing pad shown in FIG. On the other hand, in the examples, uneven wear of the polishing pad was not observed.

  Needless to say, the present invention is not limited to the embodiment, and the design can be changed as appropriate without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 20 Upper surface plate 40 Upper surface plate polishing pad 60 Wafer carrier 10 Slurry passage hole 110 Opening portion 120 Polishing pad main body 130 Adhesive layer 140 Through hole 150 Polishing surface 160 Opening inner wall polishing surface side end 170 Inclination portion θ angle W Inclination portion width

Claims (4)

A polishing pad provided on at least one surface plate of a double-side polishing machine,
Providing a plurality of openings in the polishing pad at a position facing a plurality of openings provided in one surface plate for supplying liquid and / or gas;
A polishing pad, wherein an inclined portion is provided at a corner portion constituted by a polishing surface of the polishing pad and an inner surface of the opening. A polishing pad provided on at least one surface plate of a double-side polishing machine,
Providing a plurality of openings in the polishing pad at a position facing a plurality of openings provided in one surface plate for supplying liquid and / or gas;
A polishing pad comprising an inclined portion having a fixed angle at a corner portion constituted by a polishing surface of the polishing pad and an inner surface of the opening.   The polishing pad according to claim 1, wherein an angle of the inclined portion is 10 ° to 85 °.   The polishing pad according to claim 1, wherein a width of the inclined portion is 0.1 mm to 3 mm.

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