JP2005161440A - Pad conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pad conditioner small in a fluctuation width of a dress rate. <P>SOLUTION: This pad conditioner is formed by fixing super-abrasive grains to a predetermined surface of disk-like base metal 1. The pad conditioner has a angle-shaped part 12 in an annular shape in an outer peripheral part of the disk-like base metal 1. A large super-abrasive grain 2A is electrodeposited in a top part 12A of the angle-shaped part 12, and small super-abrasive grains 5 are electrodeposited in a skirt part 12B of the angle-shaped part 12. Polishing surfaces of the top part 12A and the skirt part 12B smoothly continue. In a cross section passing through the center of the disk-like base metal, the top part 12A of the angle-shaped part 12 is formed as a circular arc, and both side skirt parts 12B of the circular arc are formed as a straight line having an inclination lowering for going away from the top part 12A, and desirably form an inclined face angle θ of 1° to 15° with the straight line parallel to a bottom surface of the disk-like base metal 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pad conditioner for dressing a polishing pad used for polishing a silicon wafer or a multilayer wiring portion on the wafer.

  Polishing of a glass substrate for hard disk, an aluminum substrate for hard disk and a silicon wafer is usually performed by using a polishing pad made of foamed polyurethane and applying a slurry in which fine particles for polishing are made turbid. As this polishing is performed, the polishing pad becomes clogged or the flatness is lowered. Therefore, it is necessary to dress the polishing pad constantly or periodically to maintain the accuracy of the flatness and eliminate the clogging.

  Conventionally, a pad conditioner has been used for this dressing (for example, Patent Document 1). In the invention of Patent Document 1, an outer peripheral portion of a flat plate-like base member is raised with a predetermined width, and a polishing grid having a uniform particle size distribution is fixed and distributed substantially uniformly on the surface of the raised portion. The raised portion is formed in a convex arcuate curved surface. According to this configuration, since the polishing pad and the pad conditioner are in surface contact when polishing, the life of the pad conditioner can be extended.

  The dress rate of the pad conditioner described in Patent Document 1 can be adjusted by changing the radius of the arcuate curved surface. The dress rate is a numerical value representing the thickness at which the pad conditioner can remove the polishing pad per unit time, and generally a unit of “μm / 10 minutes” is used.

  On the other hand, as practical use of large-diameter silicon wafers with a diameter of 300 mm has progressed, the requirements for pad conditioners have also diversified. Recently, in order to extend the life of the polishing pad, it tends to be used with a lower dress pressure. Along with this, there has been a demand for more precise control of dress performance. In particular, a pad conditioner with a small difference between the design value and the actual dress rate has been required.

JP-A-11-300600

  However, the conventional pad conditioner has the following problems.

(1) It is difficult to obtain a dress rate with small variation with respect to the design value.
The pad conditioner described in Patent Document 1 adjusts the dress rate mainly by the radius of the arc of the arcuate curved surface. However, in this method, the dress rate varies greatly due to a slight difference in radius. On the other hand, it is not easy to precisely control the radius accuracy of the arc. For this reason, it has been difficult to obtain a dress rate having a small variation with respect to the design value.

(2) It is difficult to visually distinguish products with different dress rates.
In the pad conditioner described in Patent Document 1, even if the products have different dress rates, there is no great difference in the radius of the arc of the arcuate curved surface, so that the products cannot be classified visually. If the radius of the arc is precisely measured at the time of shipping inspection or the like, it is possible to classify products having different dress rates, but the shipping inspection becomes very complicated. For this reason, it is necessary to pay special attention to process management in order to classify products having different dress rates.

  Therefore, a main object of the present invention is to provide a pad conditioner having a small dress rate variation and a dress rate as designed.

  Another object of the present invention is to provide a pad conditioner that can visually distinguish products having different dress rates.

  The present invention relates to a pad conditioner in which superabrasive grains are fixed to a predetermined surface of a disk-shaped base metal. The present invention provides a pad conditioner in which grains are electrodeposited, small superabrasive grains are electrodeposited on the skirt of the chevron, and the polishing surface of the top and skirt is smoothly connected.

That is, the pad conditioner of the present invention uses two types of superabrasive grains having different grain sizes, and increases the grain size of the top superabrasive grains to reduce the grain size of the skirt portion. By using two types of superabrasive grains having different particle sizes, the dress rate can be finely adjusted. In addition, the difference in the particle size of the superabrasive grains can be easily identified by visual observation or observation using a magnifying glass, and products having different dress rates can be identified.
It is important that the top surface to which the superabrasive grains having a large diameter are fixed and the polishing surface of the skirt portion to which the superabrasive grains having a small diameter are fixed are smoothly connected. Dressing can be performed with high accuracy by making the polished surfaces of the top and bottom portions smoothly continuous. When superabrasive grains having different particle diameters are placed on a base metal having the same height, the polished surface having a larger particle diameter becomes higher. Therefore, the polishing surface formed with small superabrasive grains is lowered and does not contribute to actual polishing. In the present invention, for example, a base surface on which small superabrasive grains are placed is raised by plating or machining, and small superabrasive grains are placed thereon, and the same polishing surface is formed by the large superabrasive grains and the small superabrasive grains. Can be height.

  The pad conditioner of the present invention is preferably constituted by a straight line having a slope that becomes lower as it goes away from the top in the longitudinal section passing through the center of the disk-shaped base metal, with the top of the chevron being an arc and the skirts on both sides of the arc. . By making the top part an arc, the entire top part can contribute to polishing. Moreover, the protrusion amount of the top part which plays the central role of grinding | polishing can be adjusted by making a base part into a straight line. In other words, the dress rate can be precisely adjusted by changing the radius of the arc at the top and the width of the top, and the variation in the dress rate with respect to the design value can be reduced. In particular, the dress rate can be adjusted more precisely by combining the change in the radius of the top arc and the width of the top and the difference in the grain size of the superabrasive grains. Further, since the difference in the radius of the top arc and the width of the top can be easily recognized visually, products having different dress rates can be easily discriminated.

  It is desirable that the straight line at the base part forms a slope angle θ of 1 ° to 15 ° with a straight line parallel to the bottom surface of the disk-shaped base metal. When the slope angle is less than 1 °, it is difficult to adjust the protrusion amount of the top portion by configuring the skirt portion with a straight line. Conversely, when the slope angle exceeds 15 °, the dress rate tends to be too high. A more desirable range of θ is 3 ° to 7 °.

  The radius R of the top arc is preferably 5 mm to 200 mm. If it is smaller than 5 mm, the dress rate becomes too high, and if it exceeds 200 mm, the dress rate is too low. A more preferable range of the arc radius R is 60 mm to 100 mm.

  In the pad conditioner of the present invention, when the width of the chevron is W and the width of the top is W1, the value of W1 / W is preferably 0.05 or more and 0.9 or less. When the value of W1 / W is less than 0.05 or exceeds 0.9, the effect of precisely adjusting the dress rate using two types of small superabrasive grains and large superabrasive grains becomes low. A more preferable range of this value is 0.2 or more and 0.8 or less.

  In the pad conditioner of the present invention, it is desirable that the particle diameter of large superabrasive grains is # 60 to # 170, and the particle diameter of small superabrasive grains is # 200 to # 800. Here, for example, when # 60 is described, this generally indicates superabrasive grains having a particle size of 127 μm to 271 μm in the same particle size range as 60/80 described in Table 2 of JIS Standard B 4130. Similarly, # 170 has the same particle size range as 170/200, and # 200 has the same particle size range as 200/230. The JIS standard describes up to 325/400, not # 800. In this case, a commercial product of # 800 may be used as a standard. The particle size of a commercial product of # 800 is 20 μm to 30 μm.

  According to the present invention, it is possible to easily manufacture a pad conditioner having a dress rate with a small variation in dress rate and a small deviation from the design value. Therefore, it is possible to provide a pad conditioner in which the dress performance is more precisely controlled in accordance with the recent trend of using the dress pressure lower. In addition, the product can be easily classified from the slope angle, etc., and the product can be classified by visual inspection or simple inspection, and quality control becomes easy.

  Embodiments of the present invention will be described below.

  FIG. 1 is a top view of the entire pad conditioner of the present invention. This pad conditioner has a donut-shaped disk-shaped base 1. The base 1 is formed of a plane whose bottom surface is perpendicular to the rotation axis of the pad conditioner, and has a hole 11 for incorporating the pad conditioner into the apparatus at the center. Furthermore, on the outer peripheral side of the base metal 1, there is a mountain-shaped portion 12 protruding upward.

  FIG. 2 is a cross-sectional view taken along a line XX cut along a line passing through the center of the disk-shaped base metal of FIG. 1, and FIG. 3 is a cross-sectional view of the base metal before electrodepositing superabrasive grains. The chevron portion 12 has a high portion as an arcuate top portion 12A and a low portion as a straight skirt portion 12B. In this figure, W indicates the width of the chevron 12, and W1 indicates the width of the arc that forms the top 12 A of the chevron 12. In the base metal 1, a straight line of the base portion 12B is connected to an arc of the top portion 12A. Further, the straight line of the skirt portion 12B intersects with the circular arc at the point A at a slope angle θ with respect to the bottom surface 13. It is easier to connect the polished surface smoothly if the point A part is processed into a round shape.

  A large superabrasive grain 2A is electrodeposited on the top part 12A, and a skirt part 12B is electrodeposited with a small superabrasive grain 2B. The small superabrasive grains 2B can be fixed on, for example, the nickel plating layer 3 to provide a polished surface smoothly connected to the large superabrasive grains 2A placed on the top 12A. The small abrasive grains 2B are also electrodeposited on the outer peripheral surface of the disk-shaped base metal 1, so that the polishing pad hitting the outer peripheral surface can be polished.

  The particle size distributions of the large superabrasive grains 2A and the small superabrasive grains 2B are desirably as narrow as possible. As is clear from FIG. 2, if the particle size distribution width is large, only the superabrasive grain 2A acts on polishing, and the small superabrasive grain 2B does not act on polishing, so superabrasive grains are used efficiently. It is not done. Thus, commercially available superabrasive grains may be further sieved and used. Diamond abrasive grains are used for the superabrasive grains 2A and 2B.

  Further, as shown in FIG. 1, the annular chevron 12 is provided with a groove 4 for allowing a polishing liquid, a polished pad, etc. to escape to the outer periphery. In this example, the grooves 4 are provided at four locations at equal intervals.

  In the above embodiment, the base metal with the hole 11 has been described as an example. However, the present invention can be applied to a pad conditioner having a base metal without a hole.

  FIG. 4 is a partial cross-sectional view of another disk-shaped base metal before electrodepositing superabrasive grains. This disk-shaped base metal 1 has a mountain-shaped portion 12 composed only of arcs. In this case as well, as in Example 1, the chevron is divided into a top 12A (range indicated by W1 in FIG. 4) and a skirt 12B (a range excluding W1 in W in FIG. 4), and the top 12A has a diameter. The large superabrasive grains 2A are fixed to the skirt 12B. Other configurations of the disk-shaped base metal 1 are the same as those in the first embodiment.

(Test Example 1)
A disk-shaped base metal having an outer diameter of 100 mm, an inner diameter of 40 mm, a chevron width W of 7 mm, and a distance between the top and bottom of the chevron part of 3.1 mm was prepared. The material of the disk-shaped base metal is stainless steel SUS304. A disc-shaped base metal was prepared by varying the radius and slope angle of the arc-shaped portion of the base metal as shown in Table 1. However, W and W1 are fixed to 7 mm and 3 mm, respectively.

Mask the parts other than the chevron of the disk-shaped base metal with a first mask, immerse it in a degreasing solution at a liquid temperature of 45 ° C. with sodium hydroxide 50 g / liter, and cathodic electrolytic degreasing at a current density of 5 A / dm ² Anodic electrolytic degreasing was performed. After washing the base metal with pure water, nickel strike plating was performed at a current density of 5 A / dm ² for 5 minutes in a nickel plating bath of 150 g / liter of nickel chloride and 100 g / liter of hydrochloric acid. Next, the substrate was plated for 15 minutes at a current density of 1 A / dm ² in a nickel bath of nickel sulfate 250 g / liter, nickel chloride 45 g / liter, and boric acid 30 g / liter.

  Next, the base of the chevron was masked with a second mask, diamond diamond of # 100 was placed on the top of the chevron of the base metal, and the diamond abrasive was temporarily fixed by plating in a nickel bath. Subsequently, the disc-shaped base metal was pulled out from the plating bath, and excess diamond abrasive grains were removed by washing with water. Next, the second mask was removed, the disc-shaped base metal was placed in a plating bath, and # 100 diamond abrasive grains were electrodeposited, and the skirt was also plated. The thickness of the plating on the skirt is determined by the size of the abrasive grains placed thereon. That is, the average particle diameter of # 100 superabrasive grains is 146 μm. Since the superabrasive grains placed on the skirts are # 325, the average grain size is 49 μm. Therefore, the thickness of the plating layer is calculated as 97 μm, which is the difference in particle diameter. By doing so, the bottom polished surface and the top polished surface were smoothly connected.

  In Sample Nos. 1 to 10, the top portion is masked with a third mask, the base metal is immersed in a plating bath, and the # 325 abrasive grains are temporarily fixed to the skirt portion. This disk-shaped base metal was pulled out from the plating bath, and excess diamond abrasive grains were removed by washing with water. Next, the disk-shaped base metal is placed in a plating bath, and # 325 diamond abrasive grains are electrodeposited. Then, the 1st mask and the 3rd mask were removed, and the pad conditioner of this invention was produced. Sample No. 10 had a chevron formed only by an arc with a radius of 60 mm, but electrodeposited with diamond grains with a large diameter on the top of width W1 and diamond grains with a small diameter on the skirt. did. Sample numbers 11 and 12 correspond to the product described in Patent Document 1 in which a chevron is formed only by arcs having a radius of 21 mm and 63 mm, and superabrasive grains of # 100 are electrodeposited on the entire chevron.

The polishing pad was polished under the following conditions using the pad conditioner thus obtained. The polishing pad used was IC1000 manufactured by Rodel Nitta Co., which had a pad rotation speed of 100 rpm, a conditioner rotation speed of 100 rpm, and a dressing pressure of 196 hPa (200 gf / cm ² ).

  The pad conditioner was evaluated by a dress rate (μm / 10 minutes) representing a thickness with which the pad conditioner can remove the polishing pad per unit time. In this test example, the dress rate of sample number 1 was set as a reference (100), and the dress rates of other sample numbers were expressed as relative values with respect to the reference. These results are also shown in Table 1.

  In Sample Nos. 1 to 9, it was found that the relative dress rate could be adjusted within a fine range of 5 to 10 by changing the radius of the arc and the slope angle. In general, the dress rate tends to increase as the radius decreases, and the dress rate tends to increase as the slope angle increases. Comparing the dress rates of Sample No. 7 and Sample No. 10 where the skirt is a straight line or an arc, the dress rate can be precisely determined by using two types of superabrasive grains even if the skirt is an arc. It can be seen that the adjustment can be made.

  The relative dress rates of Sample Nos. 11 and 12 of the comparative example are 140 and 84, which shows that the dress rate fluctuates greatly only by a slight change in radius. Assuming that the dress rate and the radius have a linear function relationship, the radii of the dress rates 100 and 105 were 51 mm and 47 mm, and the difference between them was only 4 mm and could not be discriminated visually. On the other hand, as in sample numbers 1 and 4, there was a difference of 20 mm even with only the radius, and it was possible to distinguish clearly.

(Test Example 2)
In the same manner as in Test Example 1, pad conditioners shown in Table 2 were produced. In this test example, the dress rate was examined by changing the diameters of the diamond abrasive grains at the top and bottom. The radius R of the top arc was 100 mm, the slope angle was 3 °, and the other shapes were the same as in Test Example 1. The performance was investigated in the same manner as in Test Example 1. The results obtained are shown in Table 2.

  In this test example, the sample No. 21 was used as the dress rate 100, and the dress rate of other samples was evaluated with relative values. When the abrasive grain size # 80 used at the top was atomized to # 100, the dress rate was reduced by about 20 to 25% as compared with Sample Nos. 21, 22, 23, and 24. When only the abrasive grain size at the skirt is refined from # 325 to # 600, the dress rate is reduced by about 10 to 15% as compared with sample numbers 21 and 23 and 22 and 24. Thus, the dress rate can be finely controlled by using a combination of large superabrasive grains and small superabrasive grains.

  ADVANTAGE OF THE INVENTION According to this invention, the pad conditioner which adjusted the dress rate precisely can be provided and the effective use in the field | area which grind | polishes the polishing pad of the multilayer wiring part on a silicon wafer or a wafer precisely is anticipated.

It is a top view of the pad conditioner of the present invention. It is a fragmentary longitudinal cross-sectional view of the pad conditioner of this invention. It is a partial longitudinal cross-sectional view of the base metal of the pad conditioner of FIG. FIG. 3 is a partial longitudinal sectional view of a pad conditioner of the present invention different from FIG. 2.

Explanation of symbols

1 Disc base metal
11 hole 12 Yamagata
12A Top 12B Bottom
13 Bottom
2A large super abrasive 2B small super abrasive
3 Nickel plating layer
4 groove
A Boundary point between arc and straight line R Radius of arc
W Yamagata width W1 Arc width θ Slope angle

Claims (5)

A pad conditioner having superabrasive grains fixed to a predetermined surface of a disk-shaped base metal,
Having an annular chevron on the outer periphery of the disc-shaped base metal,
Large superabrasive grains are electrodeposited on the top of the chevron,
Small superabrasive grains are electrodeposited on the base of the chevron,
A pad conditioner characterized in that a polished surface of the top and the skirt is smoothly connected.   In the longitudinal cross section passing through the center of the disk-shaped base metal, the top of the chevron is an arc, and the skirts on both sides of the arc are straight lines having a slope that decreases as the distance from the top increases, and is parallel to the bottom surface of the disk-shaped base 2. The pad conditioner according to claim 1, wherein the pad conditioner forms an inclined angle θ of 1 ° to 15 ° with a straight line.   3. The pad conditioner according to claim 1, wherein the particle size of the large superabrasive grains is # 60 to # 170, and the particle diameter of the small superabrasive grains is # 200 to # 800.   The pad conditioner according to any one of claims 1 to 3, wherein a value of W1 / W is 0.05 or more and 0.9 or less, where W is a width of the chevron and W1 is a top.   5. The pad conditioner according to claim 2, wherein a radius R of the arc is 5 mm to 200 mm.

Images