JP2003332275A - Polishing cloth, cmp apparatus provided with same, cmp method, semiconductor device and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing cloth, a CMP apparatus provided with the same and a CMP method in which in-plane uniformity of a wafer polishing quantity is improved by eliminating lack of polishing in a middle portion of the wafer by increasing a quantity of slurries to be held near the middle of the wafer during polishing. <P>SOLUTION: The polishing cloth has a plurality of grooves 35b-35h which are located approximately concentrically, and a width of the groove 35e which contacts near the middle portion of the wafer when polishing the wafer is formed wide in comparison with widths of the grooves 35b and 35h which contact near outer peripheral portions of the wafer. A distribution of the widths of the grooves approximately has a normal distribution. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing cloth, a CMP (Chemical Mechanical Polishing) apparatus having the same, a CMP polishing method, a semiconductor device and a method for manufacturing the same. In particular, a polishing cloth having improved in-plane uniformity of the amount of substrate polished, a CMP apparatus equipped with the same, a CMP polishing method,
The present invention relates to a semiconductor device and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 6 is a plan view schematically showing a polishing cloth of a conventional CMP polishing apparatus. FIG. 7 is a cross-sectional view taken along line 4-4 shown in FIG.

As shown in FIG. 6, the polishing cloth 100 is
The plane has a circular shape, and in order to improve in-plane uniformity and a polishing rate, a plurality of concentric grooves 104 are formed on the surface.
Is provided. The groove 104 is for holding the slurry during polishing.

As shown in FIG. 7, the polishing cloth 100 has a base material 101 made of an elastic material having different compressibility.
A polishing cloth 102 made of polyurethane foam or the like is attached on the base material 101. A plurality of concentric grooves 104 are provided on the upper surface of the polishing cloth 102,
The groove 104 is for holding the slurry during polishing. The groove depth a is about 0.5 mm and the groove width b
Is about 0.5 mm.

As shown in FIG. 6, a plurality of such grooves 102 are concentrically formed on the surface of a polishing cloth 100 having a circular plane. In the polishing cloth 100, grooves 102 having substantially the same width and depth are arranged at substantially equal intervals.

When polishing a wafer in a CMP apparatus, first, the back surface of the wafer is vacuum-held below the wafer-holding means. Then, the turntable is rotated by the rotary motor, and the slurry is dropped near the center of the polishing cloth 100. Next, the wafer holding means is rotated by the rotary motor to polish the surface (polishing surface) of the wafer to the polishing cloth 100.
Then, the back surface of the wafer is also pressed with air. In this way, the wafer is polished.

[0007]

SUMMARY OF THE INVENTION As described above, CMP
In the apparatus, the wafer as the substrate to be polished is pressed against the polishing cloth 100 holding the slurry in the groove 104 for polishing, but a sufficient amount of slurry cannot be held in the groove 104 near the center of the pressed wafer. Sometimes. If the amount of slurry held in the groove 104 near the center of the wafer is small as described above, the amount of polishing at the center of the wafer will be insufficient. That is, the polishing amount in the central portion of the wafer is small, and the polishing amount in the outer peripheral portion of the wafer is large, so that the in-plane uniformity of the polishing amount of the wafer is poor.

The present invention has been made in view of the above circumstances, and an object thereof is to increase the amount of slurry held near the center of the substrate during polishing, thereby eliminating insufficient polishing in the center of the substrate. It is another object of the present invention to provide a polishing cloth having improved in-plane uniformity of the amount of polished substrate, a CMP apparatus having the same, a CMP polishing method, a semiconductor device, and a manufacturing method thereof.

[0009]

In order to solve the above-mentioned problems, the polishing cloth according to the present invention is a polishing cloth having a plurality of grooves arranged substantially concentrically, and is used when polishing a substrate. The width of the groove contacting the vicinity of the central portion of the substrate is formed wider than the width of the groove contacting the vicinity of the outer peripheral portion of the substrate. The substrate is, for example, a semiconductor wafer.

According to the above polishing cloth, the width of the groove contacting the vicinity of the central portion of the substrate is formed wider than the width of the groove contacting the vicinity of the outer peripheral portion of the substrate. Therefore, when the slurry is dropped onto the polishing cloth and the polishing surface of the substrate is pressed against the polishing cloth for polishing, the slurry can be sufficiently held in the groove at the center of the substrate. By sufficiently supplying the slurry near the central portion of the substrate as described above, it is possible to prevent the polishing amount in the central portion of the substrate from decreasing, and it is possible to eliminate the insufficient polishing in the central portion of the substrate. Therefore, the surface of the substrate can be uniformly polished, and the in-plane uniformity of the substrate can be improved.

Further, in the polishing cloth according to the present invention, it is preferable that the groove width distribution has a substantially normal distribution. Thereby, the slurry can be more sufficiently supplied near the central portion of the substrate.

The polishing cloth according to the present invention is a polishing cloth having a plurality of grooves arranged substantially concentrically, and when the substrate is polished, the depth of the groove contacting the vicinity of the central portion of the substrate is It is characterized in that it is formed deeper than the depth of the groove that contacts the periphery of the substrate.

According to the above polishing cloth, when the substrate is polished, the depth of the groove contacting the vicinity of the central portion of the substrate is formed deeper than the depth of the groove contacting the vicinity of the outer peripheral portion of the substrate. There is. Therefore, when the polishing surface of the substrate is pressed against the polishing cloth for polishing, the slurry can be sufficiently held by the groove in the center of the substrate. As a result, it is possible to prevent the polishing amount in the central portion of the substrate from decreasing, and it is possible to eliminate the insufficient polishing in the central portion of the substrate. Therefore, the surface of the substrate can be uniformly polished, and the in-plane uniformity of the substrate can be improved.

Further, in the polishing cloth according to the present invention, it is preferable that the depth distribution of the groove has a substantially normal distribution. Thereby, the slurry can be more sufficiently supplied near the central portion of the substrate.

The polishing cloth according to the present invention is a polishing cloth having a plurality of grooves arranged substantially concentrically, and when the substrate is polished, the width of the groove contacting the vicinity of the central portion of the substrate is The depth of the groove that is formed wider than the width of the groove that contacts the vicinity of the outer peripheral portion of the substrate and that contacts the vicinity of the central portion of the substrate is the depth of the groove that contacts the vicinity of the peripheral portion of the substrate. It is characterized in that it is formed deeper than that.

According to the above polishing cloth, when the polishing surface of the substrate is pressed against the polishing cloth for polishing, the slurry can be sufficiently held by the groove in the central portion of the substrate. This allows
It is possible to prevent the polishing amount in the central portion of the substrate from decreasing, and it is possible to eliminate the insufficient polishing in the central portion of the substrate. Therefore, the surface of the substrate can be uniformly polished, and the in-plane uniformity of the substrate can be improved.

Further, in the polishing cloth according to the present invention, it is possible that the distribution of the width of the groove has a substantially normal distribution and the distribution of the depth of the groove has a substantially normal distribution. Thereby, the slurry can be more sufficiently supplied near the central portion of the substrate.

The CMP apparatus according to the present invention is defined by claims 1 to 6.
A polishing cloth according to any one of the above is provided.

The CMP apparatus according to the present invention is defined in any one of claims 1 to 6.
A rotatable turntable on which the polishing cloth according to any one of claims 1 to 3 is placed, a rotatable holding mechanism arranged above the turntable to hold a substrate, and the holding mechanism on the turntable side. A pressing mechanism that presses against
And a discharge mechanism arranged above the turntable for discharging the slurry to the polishing cloth.

The CMP polishing method according to the present invention is the method of claim 1.
C using the polishing cloth according to any one of
A polishing method for performing MP polishing, in which a turntable having a polishing cloth placed on an upper surface thereof is rotated, and CMP polishing is performed by pressing a polishing surface of a substrate against the polishing cloth while dropping slurry on the polishing cloth. It is characterized by

A method of manufacturing a semiconductor device according to the present invention is characterized by comprising a CMP polishing step using the polishing cloth according to any one of claims 1 to 6.

The semiconductor device according to the present invention is defined by claims 1 to 6.
CMP using the polishing cloth according to any one of
It is characterized by being manufactured through a polishing process.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view showing the outline of a CMP apparatus according to the first embodiment of the present invention, and FIG. 1B is a side view of the CMP apparatus shown in FIG. 1A. .

As shown in FIGS. 1A and 1B, CMP
The device has a disk-shaped turntable 11, and a rotary motor (not shown) is arranged on the lower surface of the turntable 11 via a rotary shaft (not shown). A polishing cloth 13 is placed on the upper surface of the turntable 11. The polishing cloth 13 will be described later. A wafer holding means 17 is arranged above the turntable 11, and a rotary motor (not shown) is arranged above the wafer holding means 17 via a rotation shaft 18. A nozzle 19 for discharging the slurry 21 is arranged above the turntable 11.

When polishing a wafer in the above CMP apparatus, first, the back surface of the wafer 15 is vacuum-held below the wafer holding means 17. Then, as shown in FIG. 1A, the turntable 11 is rotated in the direction of the arrow by the rotary motor, and the slurry 21 is discharged from the nozzle 19,
The slurry is dropped near the center of the polishing cloth 13.
Next, the wafer holding means 17 is rotated in the direction of the arrow by the rotation motor to press the surface (polishing surface) of the wafer 15 against the polishing cloth 13, and the wafer holding means 17 applies air pressure to the back surface of the wafer to press it. To do. In this way, the wafer 15 is polished.

FIG. 2 shows a polishing cloth according to the first embodiment of the present invention and is a plan view of the polishing cloth shown in FIG. 3A is a cross-sectional view taken along the line 5-5 shown in FIG. 2, and FIG. 3B is a diagram showing the distribution of the width of the groove shown in FIG. 3A. The width of this groove shows a distribution close to a normal distribution.

As shown in FIG. 3, the polishing cloth 13 has a base material 31 made of an elastic material having different compressibility, and the polishing cloth 3 made of polyurethane foam or the like is provided on the base material 31.
3 is pasted. A plurality of grooves 35b to 35h are provided on the upper surface of the polishing cloth 33, and these grooves are for holding the slurry during polishing.

As shown in FIG. 2, the grooves 35b to 35h are formed concentrically on the surface of the polishing cloth 13 having a circular plane. The groove 35e is located near the center of the wafer when the wafer is pressed against the polishing cloth 13 during polishing. The grooves 35b to 35h are formed such that the groove width becomes wider toward the center of the wafer. That is, the grooves 35b to 35
Of the h, the width of the groove 35e is the widest, and these grooves 35b ...
The width of each 35h has a distribution close to a normal distribution.

According to the first embodiment described above, the wafer 1
When polishing No. 5, the width of the groove 35e located near the central portion of the wafer 15 is widest, and the width of the groove becomes narrower toward the outer periphery of the wafer, and the polishing width has a distribution close to the normal distribution. 13 is used. Therefore, when the slurry 21 is discharged from the nozzle 19, the slurry is dropped near the center of the polishing cloth 13, and the surface (polishing surface) of the wafer 15 is pressed against the polishing cloth 13 to polish the wafer 1.
The slurry 21 can be sufficiently held by the groove 35e in the central portion of No. 5. By sufficiently supplying the slurry in the vicinity of the central portion of the wafer in this way, it is possible to prevent the amount of polishing in the central portion of the wafer from decreasing, and it is possible to eliminate insufficient polishing in the central portion of the wafer. Therefore, the surface of the wafer can be uniformly polished, and the in-plane uniformity of the wafer can be improved.

Next, a second embodiment according to the present invention will be described. The CMP apparatus according to the second embodiment is
The same CMP apparatus as in the first embodiment is used.

FIG. 4A is a sectional view showing a part of the polishing cloth according to the second embodiment. The same parts as those in FIG. 3A are designated by the same reference numerals and only different parts will be described. To do. FIG. 4B is a diagram showing the distribution of the depths of the grooves shown in FIG. The depth of this groove shows a distribution close to a normal distribution.

As shown in FIG. 4A, a polishing cloth 33 made of polyurethane foam or the like is attached on the base material 31. A plurality of grooves 45b to
45 h is provided, and these grooves are for holding the slurry during polishing.

The grooves 45b to 45h are formed concentrically on the surface of the polishing cloth 13 having a circular plane. The groove 45e is located near the center of the wafer when the wafer is pressed against the polishing cloth 13 during polishing. Groove 45
In b to 45h, the groove depth is deeper toward the center of the wafer. That is, the groove 45 among the grooves 45b to 45h.
The depth of e is the deepest, and the depth of each of these grooves 45b to 45h is close to the normal distribution.

Also in the second embodiment, the same effect as in the first embodiment can be obtained. That is,
When polishing the wafer 15, the depth of the groove 45e located near the central portion of the wafer 15 is the deepest, and the depth of the groove becomes shallower toward the outer periphery of the wafer 15, and the groove depth is close to the normal distribution. The polishing cloth 13 having the above is used. Therefore, the surface (polishing surface) of the wafer 15 is polished by the polishing cloth 13
The groove 45e in the central portion of the wafer 15 is pressed when the wafer 15 is polished.
Thus, the slurry 21 can be sufficiently retained. As a result, it is possible to prevent the polishing amount in the central portion of the wafer from decreasing, and it is possible to eliminate the insufficient polishing in the central portion of the wafer. Therefore, the surface of the wafer can be uniformly polished, and the in-plane uniformity of the wafer can be improved.

Next, a third embodiment according to the present invention will be described. The CMP apparatus according to the third embodiment is
The same CMP apparatus as in the first embodiment is used.

FIG. 5A is a sectional view showing a part of a polishing cloth according to the third embodiment. The same parts as those in FIG. 3A are designated by the same reference numerals and only different parts will be described. To do. FIG. 5B is a diagram showing the distribution of the width and depth of the groove shown in FIG. The width and depth of each groove show a distribution close to a normal distribution.

As shown in FIG. 5A, a polishing cloth 33 made of polyurethane foam or the like is attached on the base material 31. The upper surface of the polishing cloth 33 has a plurality of grooves 55b ...
55h is provided, and these grooves are for holding the slurry during polishing.

The grooves 55b to 55h are formed concentrically on the surface of the polishing cloth 13 having a circular plane. The groove 55e is located near the center of the wafer when the wafer is pressed against the polishing cloth 13 during polishing. Groove 55
In b to 55h, the groove depth is formed deeper toward the center of the wafer. That is, the groove 55 among the grooves 55b to 55h.
The width of e is the widest and the deepest, and these grooves 55b-
The width and the depth of each 55h have a distribution close to a normal distribution.

Also in the third embodiment, the same effect as in the first embodiment can be obtained. That is,
When the wafer 15 is polished, the width of the groove 55e located near the central portion of the wafer 15 is widest and deepest, and the width of the groove is narrower and shallower toward the outer periphery of the wafer. The polishing cloth 13 having a distribution in which the width and the depth are close to the normal distribution is used. For this reason, when the surface (polishing surface) of the wafer 15 is pressed against the polishing cloth 13 for polishing, the slurry 21 is removed by the groove 55e at the center of the wafer 15.
Can be held sufficiently. As a result, it is possible to prevent the polishing amount in the central portion of the wafer from decreasing, and it is possible to eliminate the insufficient polishing in the central portion of the wafer. Therefore, the surface of the wafer can be uniformly polished, and the in-plane uniformity of the wafer can be improved.

The present invention is not limited to the above embodiment, and can be implemented with various modifications.

The present invention can also be carried out as a method of manufacturing a semiconductor device including a CMP polishing step using the above-mentioned polishing cloth, and through the CMP polishing step using the above-mentioned polishing cloth. It is also possible to implement it as a manufactured semiconductor device.

[0042]

As described above, according to the present invention, by increasing the amount of slurry held near the center of the substrate during polishing, the lack of polishing at the center of the substrate is eliminated, and the amount of substrate polished is uniform within the surface. Polishing cloth with improved durability, C equipped with it
It is possible to provide an MP device, a CMP polishing method, a semiconductor device and a manufacturing method thereof.

[Brief description of drawings]

FIG. 1A is a plan view schematically showing a CMP apparatus according to a first embodiment of the present invention, and FIG.
It is a side view of the CMP apparatus shown in (a).

FIG. 2 shows a polishing cloth according to a first embodiment of the present invention, and is a plan view of the polishing cloth shown in FIG.

3A is a sectional view taken along line 5-5 shown in FIG. 2, and FIG. 3B is a diagram showing a distribution of the width of the groove shown in FIG.

FIG. 4A is a cross-sectional view showing a part of a polishing cloth according to the second embodiment, and FIG. 4B is a view showing distribution of the depth of the groove shown in FIG.

5A is a cross-sectional view showing a part of a polishing cloth according to a third embodiment, and FIG. 5B is a view showing the distribution of the width and depth of the groove shown in FIG. is there.

FIG. 6 is a plan view schematically showing a polishing cloth of a conventional CMP polishing apparatus.

7 is a cross-sectional view taken along line 4-4 shown in FIG.

[Explanation of symbols]

11 ... Turntable 13,100 ...
Polishing cloth 15 ... Wafer 17 ... Wafer holding means 18 ... Rotating shaft 19 ... Nozzle 21 ... Slurry 31, 101 ...
Base materials 33, 102 ... Polishing cloths 35b to 35h, 45b to 45h, 55b to 55h, 1
04 ... Groove a ... Groove depth b ... Groove width c ... Adjacent groove width

Claims (11)

[Claims] 1. A polishing cloth having a plurality of grooves arranged substantially concentrically, wherein the width of the groove contacting the vicinity of the central portion of the substrate when polishing the substrate is near the outer peripheral portion of the substrate. The polishing cloth is characterized in that it is formed wider than the width of the groove that comes into contact with. 2. The polishing cloth according to claim 1, wherein the distribution of the width of the groove has a substantially normal distribution. 3. A polishing cloth having a plurality of grooves arranged in a substantially concentric pattern, wherein the depth of the groove that contacts the vicinity of the central portion of the substrate when polishing the substrate is the outer peripheral portion of the substrate. A polishing cloth characterized in that it is formed deeper than the depth of the groove that contacts the vicinity. 4. The polishing cloth according to claim 3, wherein the distribution of the depth of the groove has a substantially normal distribution. 5. A polishing cloth having a plurality of substantially concentrically arranged grooves, wherein the width of the groove that contacts the vicinity of the central portion of the substrate when polishing the substrate is near the outer peripheral portion of the substrate. Is formed wider than the width of the groove that contacts the substrate, and the depth of the groove that contacts the central portion of the substrate is deeper than the depth of the groove that contacts the peripheral portion of the substrate. A polishing cloth that is characterized by being 6. The polishing cloth according to claim 5, wherein the distribution of the width of the groove has a substantially normal distribution, and the distribution of the depth of the groove has a substantially normal distribution. 7. A CMP apparatus comprising the polishing cloth according to any one of claims 1 to 6. 8. A rotatable turntable on which the polishing cloth according to claim 1 is placed, and a rotatable holder arranged above the turntable for holding a substrate. A CMP apparatus comprising: a mechanism, a pressing mechanism that presses the holding mechanism toward the turntable, and a discharge mechanism that is disposed above the turntable and that discharges the slurry to a polishing cloth. 9. A polishing method for performing CMP polishing using the polishing cloth according to any one of claims 1 to 6, comprising rotating a turntable having the polishing cloth mounted on an upper surface thereof. A CMP polishing method characterized in that CMP polishing is performed by pressing a polishing surface of a substrate against a polishing cloth while dropping a slurry onto the polishing cloth. 10. A method of manufacturing a semiconductor device, comprising a CMP polishing step using the polishing cloth according to claim 1. 11. A semiconductor device manufactured through a CMP polishing step using the polishing cloth according to claim 1. Description: