JP2016068194A - Polishing pad - Google Patents

Abstract

SOLUTION: There are provided polishing pads 1a and 1b having polishing surfaces 4a and 4b for polishing a polishing object such as a semiconductor wafer. At least one of a water repellent pattern P1 being a water repellency-treated first area and a hydrophilicity-treated hydrophilic pattern P1' is provided on the polishing surfaces 4a and 4b and a part except for the pattern becomes a second area P0 different in hydrophilicity. The pattern may be a radial shape, a concentric shape or a lattice shape.EFFECT: Since the water repellent patter P1 or the hydrophilic pattern P1' as a first area different in hydrophilicity and the second area P0 are provided on a polishing surface, a holding property and a discharge property of slurry can be controlled by water repellency of the water repellent pattern and hydrophilicity of the hydrophilic patter, so that control of the slurry distribution in the polishing surface and the polishing rate-improving effect can be provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a polishing pad, and more particularly to a polishing pad suitable for polishing a surface of a semiconductor wafer, a glass substrate for hard disk, an aluminum substrate, or the like by chemical mechanical polishing (CMP).

Conventionally, a polishing pad for polishing an object to be polished such as a semiconductor wafer, a glass substrate for hard disk, and an aluminum substrate is well known.
In this type of polishing pad, grooves of various shapes are formed on the polishing surface of the polishing pad in order to control the retention and discharge properties of the slurry (Patent Document 1).

JP 11-267961 A

By setting the shape of the groove to various shapes, it is possible to improve the retention of the slurry or the discharge performance, but on the other hand, depending on the uneven surface due to the formation of the groove, it is to be polished. The flatness of objects may be adversely affected.
In view of such circumstances, the present invention provides a polishing pad capable of controlling the retention and discharge properties of a slurry while preventing adverse effects on the flatness of an object to be polished.

The present invention provides a polishing pad including a polishing sheet having a polishing surface for polishing an object to be polished, the polishing surface having a first region and a second region having different hydrophilicity, and the above The first region is formed in a pattern.
The first region may be formed by water repellent treatment or may be formed by hydrophilic treatment. Further, the first region may be formed at least ½ or more in the thickness direction from the polishing surface side of the polishing sheet, and the polishing sheet communicates in a three-dimensional network from the polishing surface to the surface opposite to the polishing surface. You may have a bubble to do. Further, the pattern provided on the polishing surface may be radial, concentric, or lattice.

According to the present invention, since the first surface and the second region having different hydrophilicity are formed on the polishing surface and the first region is formed in a pattern, the slurry is held by the pattern. Therefore, it is possible to control the slurry distribution on the polishing surface and improve the polishing rate.
Furthermore, since the retention and discharge properties of the slurry can be controlled without providing a conventional groove, it is possible to suppress the reduction in flatness of the object to be polished due to the unevenness derived from the groove.

(A), (b) is sectional drawing which shows the Example of this invention, respectively. The top view which shows water-repellent pattern P1 of 1st Example of this invention, and hydrophilic pattern P1 'of 2nd Example. The top view which shows the water-repellent pattern P2 of 3rd Example of this invention, and the hydrophilic pattern P2 'of 4th Example. The top view which shows the water-repellent pattern P3 of 5th Example of this invention, and the hydrophilic pattern P3 'of 6th Example.

Hereinafter, the present invention will be described with reference to the illustrated embodiment. In FIG. 1 (a), a polishing pad 1a according to the present invention includes a polishing sheet 3a in which a number of vertically long bubbles 2a are formed in the thickness direction. One surface of the polishing sheet 3a is a polishing surface 4a for polishing an object not shown.
Moreover, the base material 5a which has rigidity is provided in the other surface of the polishing sheet 3a, and the double-sided tape 6a is provided in the surface on the opposite side to the polishing sheet 3a of the base material 5a. The polishing pad 1a is bonded and fixed to a polishing surface plate of a polishing apparatus (not shown) by the double-sided tape 6a.
When the object to be polished is polished by the polishing surface 4a, the slurry is supplied between the polishing surface 4a and the surface to be polished by a slurry supply device (not shown), and both are relatively opposite to each other. The polishing process can be carried out by rotating to the right.
Further, the polishing pad 1b according to the present invention in FIG. 1 (b) includes a polishing sheet 3b in which a large number of bubbles 2b are formed, and one surface of the polishing sheet 3b is a polishing object (not shown). A polishing surface 4b to be polished is provided, and other configurations are the same as those in FIG.

As shown in FIG. 2, the polished surfaces 4a and 4b are provided with a water-repellent pattern P1 as a first region subjected to water-repellent treatment. In the illustrated embodiment, the water-repellent pattern P1 is spaced by 45 degrees. It is formed radially. On the other hand, the polished surfaces 4a and 4b other than the water-repellent pattern P1 formed in a radial pattern are second regions P0 having different hydrophilicity from the first region.
The polishing sheets 3a and 3b can be, for example, soft urethane sheets such as polyurethane sheets as shown in FIGS. 1A and 1B, and the water repellent pattern P1 is a water repellent. Can be used. Although the water repellent is not particularly limited, a fluorine-based or silicon-based water repellent can be used. For this reason, in the present embodiment, the hydrophilicity of the water-repellent pattern P1, which is the first region, can be set to be smaller than the hydrophilicity of the second region P0.

Further, since the bubbles 2a and 2b are communicated in a three-dimensional network from the polishing surfaces 4a and 4b to the surface opposite to the polishing surface, the water repellent can permeate in the thickness direction in the bubbles 2a and 2b. it can. Accordingly, the water repellent pattern P1 can be formed in the thickness direction of the polishing sheets 3a and 3b, and the water repellent pattern P1 can be maintained even when the polishing surfaces 4a and 4b are worn. Can last.
Further, since the polishing sheets 3a and 3b are communicated in a three-dimensional mesh shape up to the surface opposite to the polishing surface, the polishing sheets 3a and 3b necessarily communicate with a direction perpendicular to the thickness direction of the polishing sheet. Therefore, the slurry that has penetrated into the polishing sheets 3a and 3b can also move in a direction perpendicular to the thickness direction of the polishing sheets 3a and 3b. At this time, since the water repellent pattern P1 penetrates in the thickness direction of the polishing sheet, the movement of the slurry that has penetrated into the polishing sheets 3a and 3b is controlled by the water repellent pattern. As a result, it is possible to control the retention and discharge properties of the slurry inside the polishing sheets 3a and 3b. Thereby, compared with the case where the hydrophilic pattern P1 ′ is formed only on the polished surface, the effect of retaining and discharging the slurry is increased, which is preferable.
At this time, it is desirable that the water-repellent pattern P1 is formed at least 1/2 or more in the thickness direction from the polishing surfaces 4a and 4b side of the polishing sheets 3a and 3b.

In the first embodiment described above, since the water-repellent pattern P1 is formed in a radial pattern, the slurry supplied between the polishing surfaces 4a and 4b and the object to be polished is a centrifugal force accompanying the rotation of the polishing surfaces 4a and 4b. Thus, when approaching on the radial line of the water repellent pattern P1, the water tends to be discharged outward in the radial direction of the polishing pads 1a and 1b through the water repellent pattern P1. That is, since the water repellent pattern P1 has water repellency, it is difficult for the slurry to move over the line and move to the adjacent more hydrophilic region, and the slurry is discharged along the radial line in the radial direction of the circle. .
With regard to the level of discharge of this slurry, the formation angle in the radial direction forming the water repellent pattern P1, that is, the application area of the water repellent according to the number of lines formed and the line width, or the repellent for forming the water repellent pattern P1. It is possible to control by appropriately adjusting the type of liquid etc., and thereby the slurry distribution on the polishing surface can be controlled.
In addition, since control of the discharge | emission property of the said slurry is not based on the groove | channel formed in polishing surface 4a, 4b, the unevenness | corrugation derived from a groove | channel does not exist in polishing surface 4a, 4b. Therefore, it is possible to suppress a reduction in flatness due to the unevenness.

In the first embodiment described above, the radial water-repellent pattern P1 having water repellency is provided as the first region on the polishing surfaces 4a and 4b. Instead, the hydrophilic pattern having the same shape and subjected to the hydrophilic treatment is provided. P1 ′ may be provided as the first region. That is, in the second embodiment, the hydrophilicity of the hydrophilic pattern P1 ′ that is the first region is set to be larger than the hydrophilicity of the second region P0.
In the second embodiment, as the hydrophilic agent for forming the hydrophilic pattern P1 ′, for example, carboxylate, sulfonate, sulfate ester salt, phosphate ester salt, alkylcarboxylic acid, amine salt, quaternary ammonium Hydrophilic compounds such as salts, hydrophilic ester-based, ether-based, ester-ether-based, amide-based compounds can be used, but water-insoluble which interacts with water molecules by electrostatic interaction or hydrogen bond. Hydrophilic compounds are preferred. Since a water-insoluble hydrophilic compound is difficult to dissolve in water, which is the main component of the slurry, the hydrophilic agent can be prevented from being dissolved in the slurry and discharged from the polishing surfaces 4a and 4b, and the effect of the invention is long. It is preferable because the time can be maintained.
Also in the second embodiment, since the bubbles 2a and 2b communicate with the polishing sheet 3a and 3b in a three-dimensional network from the polishing surfaces 4a and 4b to the surface opposite to the polishing surface, the hydrophilic agent is the polishing sheet. Can penetrate in the thickness direction. Thereby, even if the polishing surfaces 4a and 4b are worn by polishing, the hydrophilic pattern P1 ′ can be maintained, so that the effect of the invention can be maintained for a long time.
Further, since the polishing sheets 3a and 3b are communicated in a three-dimensional mesh shape up to the surface opposite to the polishing surface, the polishing sheets 3a and 3b necessarily communicate with a direction perpendicular to the thickness direction of the polishing sheet. As a result, the slurry that has penetrated into the polishing sheets 3a and 3b can also move in a direction perpendicular to the thickness direction of the polishing sheets 3a and 3b. At this time, since the hydrophilic pattern P1 ′ penetrates in the thickness direction of the polishing sheet, the movement of the slurry that has penetrated into the polishing sheets 3a and 3b is controlled by the hydrophilic pattern P1 ′. As a result, it is possible to control the retention and discharge properties of the slurry inside the polishing sheets 3a and 3b. Thereby, compared with the case where hydrophilic pattern P1 'is formed only in the grinding | polishing surface, the effect of holding | maintenance of a slurry and discharge property increases, and it is preferable.

In the second embodiment, since the hydrophilic pattern P1 ′ is formed of a hydrophilic agent, the slurry supplied between the polishing surfaces 4a and 4b and the object to be polished is made hydrophilic by the centrifugal force accompanying the rotation of the surface plate. When approaching the radial line of the sexual pattern P1 ′, the slurry mainly composed of water tends to stay on the radial line due to its affinity. For this reason, as compared with the case where the hydrophilic pattern P1 ′ is not formed, the slurry is not easily discharged to the outside of the polishing pads 1a and 1b, and the retention property is improved.
With regard to the retention of the slurry, the hydrophilic agent coating area or the hydrophilic agent for forming the hydrophilic pattern P1 ′ is determined depending on the number of the radial pattern forming the hydrophilic pattern P1 ′ and the line width. It is possible to control by appropriately adjusting the type and the like. As a result, it is possible to obtain an effect of controlling the slurry distribution on the polishing surfaces 4a and 4b and improving the polishing rate.
Also in the second embodiment, the control of slurry retention is not based on the grooves formed on the polished surface, and therefore there are no irregularities derived from the grooves on the polished surfaces 4a and 4b. Accordingly, reduction in flatness due to unevenness can be suppressed.

The polishing pads 1a and 1b having the water-repellent pattern P1 and the polishing pads 1a and 1b having the hydrophilic pattern P1 ′ can be manufactured by a similar manufacturing method.
The outline of the production method will be described. First, a flexible urethane sheet is prepared by a conventionally known wet coagulation method.
That is, a polyurethane resin solution containing dimethylformamide (DMF) is applied on a flat substrate, and the substrate coated with the polyurethane resin solution is immersed in a coagulation liquid containing water as a main component. Then, after the polyurethane resin is solidified and regenerated into a sheet, the DMF in the remaining polyurethane resin solution is removed. Next, drying is performed by evaporating the water contained in the urethane resin using a dryer. When moisture in the resin space evaporates, a large number of vertically long bubbles 2a as shown in FIG. 1A are formed in the thickness direction in the resin, and the bubbles 2a are connected in a three-dimensional mesh shape in the thickness direction. A polishing sheet 3a made of a urethane sheet can be obtained.
Moreover, when 5 wt% to 25 wt% of an organic solvent having a solubility in water such as ethyl acetate smaller than DMF is added to the polyurethane resin solution, a large number of micropores 2b shown in Fig. 1 (b) are formed, and A polishing sheet 3b made of a soft urethane sheet in which the bubbles 2b communicate with each other in a three-dimensional network in the thickness direction can be obtained.
Next, a PET mask having the above pattern formed thereon is placed on the polishing sheets 3a and 3b, and a water repellent solvent or a hydrophilic solvent is applied thereon by spraying.
Thereafter, the PET mask is removed, and the soft urethane sheet is dried in an environment of 80 to 150 ° C. to fix the water repellent or hydrophilic agent. Furthermore, a base material is attached to the surface opposite to the surface of the soft urethane sheet opposite to the water-repellent agent by using an adhesive, and the polishing pad is fixed to the polishing surface plate on the surface opposite to the soft urethane sheet of the PET base material. The double-sided tape is bonded to produce polishing pads 1a and 1b.

FIG. 3 shows a third embodiment and a fourth embodiment of the present invention. In the third embodiment, a water repellent pattern P2 as a first region subjected to a water repellent treatment is provided on the polished surfaces 4a and 4b. In the fourth embodiment, a hydrophilic pattern P2 ′ as a first region subjected to hydrophilic treatment is provided on the polishing surfaces 4a and 4b. In any of the third and fourth embodiments, the polishing surfaces 4a and 4b other than the patterns P2 and P2 ′ are second regions P0 having different hydrophilicity from the first region. ing.
The difference between the third embodiment, the fourth embodiment and the first embodiment, the second embodiment is whether each pattern is radial or concentric, and the third embodiment, the fourth embodiment. Other configurations in the example are the same as those in the first and second embodiments.
According to the water repellent pattern P2 of the third embodiment, since the water repellent pattern P2 is formed concentrically, the slurry supplied between the polishing surfaces 4a and 4b and the object to be polished is the rotation of the surface plate. When a circular line constituting the concentric water-repellent pattern P2 is approached by the centrifugal force associated with the above, it tends to stay at the inner peripheral portion of the line. That is, since the water repellent pattern P2 has water repellency, it is difficult for the slurry to flow over the concentric line and flow to the adjacent higher hydrophilic region, so that the slurry hardly flows out to the outer periphery of the polishing surface. , Slurry retention is increased. As a result, it is possible to obtain an effect of controlling the slurry distribution on the polishing surfaces 4a and 4b and improving the polishing rate.
On the other hand, according to the hydrophilic pattern P2 ′ of the fourth embodiment, since the hydrophilic pattern P2 ′ is formed of a hydrophilic agent, the slurry supplied between the polishing surfaces 4a and 4b and the object to be polished is When approaching the concentric line of the concentric hydrophilic pattern P2 ′ by the centrifugal force accompanying the rotation of the platen, the slurry mainly composed of water tends to stay on the concentric line due to its affinity. For this reason, the slurry tends to stay as compared with the case where the hydrophilic pattern P2 ′ is not formed. For this reason, as compared with the case where the hydrophilic pattern P1 ′ is not formed, the slurry is less likely to flow to the outer periphery of the polishing surface, and the retention of the slurry is enhanced.
As a result, it is possible to obtain an effect of controlling the slurry distribution on the polishing surfaces 4a and 4b and improving the polishing rate.

FIG. 4 shows a fifth embodiment and a sixth embodiment of the present invention. In the fifth embodiment, a water repellent pattern P3 as a first region subjected to water repellent treatment is provided on the polished surfaces 4a and 4b. In the sixth embodiment, a hydrophilic pattern P3 ′ as a first region subjected to hydrophilic treatment is provided on the polishing surfaces 4a and 4b.
Also in the fifth and sixth embodiments, the polishing surfaces 4a and 4b other than the patterns P3 and P3 ′ are the second regions P0 having different hydrophilicity from the first region. The configuration other than the patterns P3 and P3 ′ is configured in the same manner as in the above-described embodiment.
In any of the embodiments, the patterns P3 and P3 ′ are formed in a lattice shape. According to the water-repellent pattern P3 of the fifth embodiment, the water-repellent pattern P3 is formed concentrically. When the slurry supplied between the surfaces 4a and 4b and the object to be polished approaches the grid-like line constituting the grid-like water-repellent pattern P2 by the centrifugal force accompanying the rotation of the surface plate, the slurry is partitioned in a grid-like shape. It returns to the inside of the area, and it tends to stay in the compartment. In other words, in the lattice-like water-repellent pattern P3, it is inhibited from flowing out to the more hydrophilic region adjacent to the region surrounded by the partition constituting the lattice-like water repellent pattern P3. Is less likely to flow out, the retention of the slurry is enhanced, and the effect of controlling the slurry distribution on the polishing surface and improving the polishing rate can be obtained.
Further, according to the hydrophilic pattern P3 ′ of the sixth example, since the hydrophilic pattern P3 ′ is formed of a hydrophilic agent, the slurry supplied between the polishing surfaces 4a and 4b and the object to be polished is constant. When approaching on a grid-like line due to centrifugal force accompanying the rotation of the board, the slurry containing water as a main component tends to stay on the line, and the slurry hardly flows out to the outer periphery of the polishing surface. Thereby, the retention property of the slurry is enhanced, and the effect of controlling the slurry distribution on the polishing surface and improving the polishing rate can be obtained.

As can be understood from each of the above-described embodiments, the water drainage and retention of the slurry can be obtained by the water-repellent patterns P1 to P3 and the hydrophilic patterns P1 ′ to P3 ′. Producing polishing pads 1a and 1b having suitable drainage or retention by appropriately setting the hydrophilicity based on the number of lines formed, line width, or the type of water repellent or hydrophilic agent. Can do.
The above patterns are not limited to those shown in the drawings, and may be various shapes such as spirals and S shapes, irregular patterns, and a combination of a water repellent pattern and a hydrophilic pattern. Of course, it is also good.
In any case, in the present invention, the polishing surfaces 4a and 4b have first and second regions having different hydrophilicity, and the first region is formed in a pattern. Good.
Further, in the above embodiment, the grooves are not formed on the polishing surfaces 4a and 4b. However, the grooves are not necessarily formed, and the above patterns and grooves may be used in combination as long as there is no adverse effect due to the grooves. Good.
In addition, about the application method to the water repellent and the hydrophilic agent on the polishing surfaces 4a and 4b, the spray method is described in the embodiment, but is not limited thereto. A coating method using a screen printer or gravure printing may be used.

1a, 1b Polishing pad 2a, 2b Bubble 3a, 3b Polishing sheet 4a, 4b Polishing surface P0 Second region P1-P3 Water repellent pattern (first region)
P1 ′ to P3 ′ hydrophilic pattern (first region)

Claims (7)

In a polishing pad comprising a polishing sheet having a polishing surface for polishing an object to be polished,
A polishing pad comprising a first region and a second region having different hydrophilicity on the polishing surface, wherein the first region is formed in a pattern.   The polishing pad according to claim 1, wherein the first region is formed by a water repellent treatment.   The polishing pad according to claim 1, wherein the first region is formed by a hydrophilic treatment.   The polishing pad according to claim 1, wherein the first region includes a portion formed by water repellent treatment and a portion formed by hydrophilic treatment.   The polishing pad according to any one of claims 1 to 4, wherein the first region is formed at least ½ or more in a thickness direction from a polishing surface side of the polishing sheet.   6. The polishing pad according to claim 1, wherein the polishing sheet communicates in a three-dimensional network from the polishing surface to the surface opposite to the polishing surface.   The polishing pad according to claim 1, wherein the pattern provided on the polishing surface is radial, concentric, or lattice-shaped.

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