JP2001001255A - Polishing cloth, polishing apparatus, and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing cloth capable of equalizing an amount of polishing on a surface to be polished of a material to be polished, a polishing apparatus equipped with the polishing cloth, and a semiconductor device using the polishing apparatus. A manufacturing method is provided. SOLUTION: The polishing cloth 100 includes a surface region in which at least one recess 110 for holding an abrasive is formed. The concave portion 110 is formed such that the amount of the abrasive retained per unit area on the surface of the polishing cloth decreases from the center to the outer periphery of the polishing cloth 100. The recess 110 may be groove-shaped or dot-shaped. When the plurality of recesses 110 are formed in the surface region, the plurality of recesses 110 may be formed in a groove shape and concentrically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing cloth, a polishing apparatus, and a method for manufacturing a semiconductor device, and more particularly to a polishing cloth, a polishing apparatus, and a method for manufacturing a semiconductor device suitable for a chemical mechanical polishing method.

[0002]

2. Description of the Related Art In recent years, with the demand for miniaturization and high integration of semiconductor devices, wiring layers have been formed in multiple layers. As the number of wiring layers increases, a wiring layer formed on an upper layer is more likely to have a step in the wiring layer. When this step is increased, it causes disconnection of the wiring layer, which is a serious problem in achieving miniaturization and high integration of the semiconductor device. At present, a chemical mechanical polishing (hereinafter, referred to as "CMP") method is employed as one of the means for eliminating the step.

[0003] The polishing cloth of the polishing apparatus plays an important role in favorably performing the CMP method. That is, CMP
The planarization by the method largely depends on the polishing cloth. Generally, grooves are formed in this polishing cloth in order to polish the wafer efficiently. The pattern, shape, number, and cross-sectional shape of the grooves determine the amount of abrasive retained per unit area on the surface of the polishing pad. The amount of retained abrasive greatly affects the polishing rate within the wafer surface. In other words, the polishing rate increases as the abrasive holding amount increases. For this reason, it has been considered that if the amount of the retained abrasive is non-uniform on the surface of the polishing cloth, the polishing rate also becomes non-uniform (for example, JP-A-10-71561). That is, attempts have been made to achieve uniformity in the wafer surface by making the slurry holding amount uniform.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing cloth capable of equalizing the amount of polishing on a surface to be polished of a material to be polished, a polishing apparatus equipped with the polishing cloth, and a polishing apparatus having the polishing cloth. And a method of manufacturing a semiconductor device using the same.

[0005]

(Abrasive cloth) The polishing cloth of the present invention is a polishing cloth including a surface region in which at least one concave part for holding an abrasive is formed.
The polishing pad is formed so that the amount of the abrasive retained per unit area on the surface of the polishing pad becomes smaller from the central portion to the outer peripheral portion of the polishing pad.

The inventor of the present application has formed a recess so that the polishing agent holding amount per unit area of the polishing cloth becomes smaller from the central portion to the outer peripheral portion of the polishing cloth, and the polishing position of the workpiece is adjusted. It has been found that the adjustment can make the polishing amount uniform in the surface to be polished of the material to be polished. For example, it has been found that the polishing amount of the material to be polished can be made uniform within the surface to be polished by adjusting the polishing position of the material to be polished as follows.

[0007] When polishing a material to be polished, a portion of the material to be polished in which the abrasive is difficult to spread is mainly located in the surface region of the polishing cloth (the central portion of the polishing cloth) having a large amount of the abrasive retained per unit area. (For example, the central portion of the material to be polished) is polished. Further, in the surface region of the polishing cloth (the outer peripheral portion of the polishing cloth) where the amount of the abrasive retained per unit area is small, mainly the portion of the material to be polished in which the abrasive easily flows (for example, the outer peripheral portion of the polishing material). To be polished. As described above, it has been found that uniformity of the polishing rate in the surface to be polished can be easily improved by adjusting the position of the material to be polished and polishing the material to be polished. This makes it possible to easily equalize the amount of polishing in the surface to be polished.

[0008] Examples of the shape of the concave portion include a groove shape and a dot shape.

Further, a plurality of the recesses may be formed in the surface region, and the plurality of the recesses may be formed in a groove shape and concentrically.

The following advantages are obtained by adopting the concave portion in this mode. In this embodiment, the concave portion has a groove shape and is formed concentrically. For this reason, in the surface region of the polishing cloth, only by controlling the interval between the recesses, the width or the depth, the amount of the abrasive retained per unit area increases from the center to the outer periphery of the polishing cloth. A recess can be formed so as to be smaller. Further, it is easy to determine the polishing position of the material to be polished on the polishing cloth.

Further, the abrasive holding amount per unit area is as follows:
Examples of the mode of forming the concave portion so as to become smaller from the central portion to the outer peripheral portion of the polishing cloth include the following two modes.

(1) First, the occupied area of the concave portion per unit area decreases from the central portion to the outer peripheral portion of the polishing pad. As this aspect,
For example, the following three can be cited.

An embodiment wherein the number of the recesses per unit area decreases from the center to the outer periphery of the polishing pad.

[0014] The width of the recess may be reduced from the center to the outer periphery of the polishing pad.

The number of the concave portions per unit area decreases from the central portion of the polishing cloth toward the outer peripheral portion, and the width of the concave portion increases from the central portion of the polishing cloth toward the outer peripheral portion. An aspect that becomes narrower.

(2) Secondly, the recess is formed such that the depth of the recess decreases from the center to the outer periphery of the polishing pad.

Further, the concave portion can be formed by combining the following embodiments (a) and (b). (A) an embodiment in which the recess is formed such that the area occupied by the recess per unit area on the surface of the polishing cloth decreases from the center to the outer periphery of the polishing cloth; b) A mode in which the recess is formed such that the depth of the recess decreases from the center to the outer periphery of the polishing pad.

In the case where the above embodiments (a) and (b) are combined, in the embodiment (a), the number of the recesses per unit area decreases as going from the center to the outer periphery of the polishing pad. At least one of an aspect and an aspect in which the width of the concave portion becomes narrower from the central portion to the outer peripheral portion of the polishing pad.

(Polishing Apparatus) The polishing apparatus of the present invention is a polishing apparatus comprising: polishing means for rubbing a polishing cloth and a material to be polished; and abrasive supplying means for supplying a polishing agent to the surface of the polishing cloth. The polishing cloth is the above-described polishing cloth of the present invention.

The polishing apparatus of the present invention has the polishing cloth of the present invention attached thereto. For this reason, from the characteristics of the polishing cloth, it is possible to easily improve the uniformity of the polishing rate on the surface to be polished simply by adjusting the polishing position of the material to be polished. As a result, the polishing amount in the surface to be polished can be easily and simply made uniform.

(Method of Manufacturing Semiconductor Device) The method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device including the step of polishing a semiconductor wafer. The polishing is performed using a polishing apparatus.

Here, the semiconductor wafer means, for example, a semiconductor substrate itself or a semiconductor wafer and a semiconductor wafer and a predetermined layer formed on the semiconductor substrate.

By polishing the semiconductor wafer using the polishing apparatus of the present invention, the uniformity of the polishing rate within the semiconductor wafer surface can be easily improved. As a result, it is possible to easily and easily equalize the polishing amount in the semiconductor wafer surface. Further, since the polishing amount can be made uniform in the surface of the semiconductor wafer, even if the wiring layer is formed in multiple layers, a problem such as disconnection does not occur. Therefore, according to the method for manufacturing a semiconductor device of the present invention, miniaturization and high integration of the semiconductor device can be achieved.

Further, a method of manufacturing a semiconductor device according to the present invention
Further, for the polishing cloth of the present invention described above, including the step of determining the polishing position of the semiconductor wafer, the step of determining the polishing position of the semiconductor wafer includes the step of polishing a test semiconductor wafer, In the step of polishing the test semiconductor wafer, a polishing position of the semiconductor wafer can be determined based on a polishing rate in a polishing surface of the test semiconductor wafer.

The polishing position of the semiconductor wafer is determined based on the polishing rate in the polishing surface of the test semiconductor wafer.
For example, it is preferable to determine as follows.

(1) In the step of polishing the test semiconductor wafer, if the polishing rate of the outer peripheral portion of the test semiconductor wafer is faster than the polishing rate of the central portion of the test semiconductor wafer, Is performed such that the center of the semiconductor wafer is positioned on the outer peripheral side of the polishing cloth from the position of the polishing cloth on which the center of the test semiconductor wafer is polished.

Hereinafter, the reason why it is preferable to determine the polishing position of the semiconductor wafer in this manner will be described. The more the polishing cloth is located on the outer peripheral side, the smaller the amount of the abrasive retained. Also,
When the holding amount of the abrasive decreases, the semiconductor wafer is harder to be cut by that much. Therefore, in the above case,
By locating the center of the semiconductor wafer on the outer peripheral side of the polishing cloth, the outer peripheral portion of the semiconductor wafer is mainly polished on the outer peripheral side of the polishing cloth. Therefore,
The polishing rate at the outer peripheral portion of the semiconductor wafer can be reduced. As a result, according to this, the difference between the polishing rate at the center portion of the semiconductor wafer and the polishing rate at the outer peripheral portion can be further reduced.

(2) In the step of polishing the test semiconductor wafer, if the polishing rate of the outer peripheral portion of the test semiconductor wafer is lower than the polishing rate of the central portion of the test semiconductor wafer, Is performed such that the center of the semiconductor wafer is positioned closer to the center of the polishing cloth than the position of the polishing cloth on which the center of the test semiconductor wafer is polished.

Hereinafter, the reason why it is preferable to determine the polishing position of the semiconductor wafer in this way will be described. The closer to the center of the polishing cloth, the greater the amount of the abrasive retained. In addition, when the holding amount of the polishing agent is increased, the semiconductor wafer is more likely to be cut by that much. For this reason, in the above case, the center of the semiconductor wafer is located closer to the center of the polishing pad, so that the outer peripheral portion of the semiconductor wafer is mainly polished at the center of the polishing pad. become. Therefore, the polishing rate of the outer peripheral portion of the semiconductor wafer can be increased. As a result, according to this, the difference between the polishing rate at the center portion of the semiconductor wafer and the polishing rate at the outer peripheral portion can be further reduced.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a plan view schematically showing a polishing pad according to a first embodiment. FIG. 2 shows regions (A), (B) and (C) of the polishing cloth of FIG.
5 is a schematic cross-sectional view of FIG. 5, wherein the centers of the regions (A), (B) and (C) are located on a line connecting one point on the outer periphery from the center of the polishing pad.

In the first embodiment, an example is shown in which a groove is applied as a concave portion. The polishing cloth 100 has a plurality of grooves 110 formed on a polishing surface. These grooves 11
Numerals 0 are formed concentrically, and are formed such that the area occupied by the groove per unit area decreases from the center to the outer periphery. That is, the groove 11
The density of the pattern of 0 (the number of grooves formed per unit area) decreases from the center to the outer periphery (from the region (A) to (C)). More specifically, the interval S10 between the grooves 110
Are gradually increased from the center toward the outer periphery.

The groove 110 has a function of holding an abrasive on the surface of the polishing cloth 100. The polishing is promoted by the presence of the abrasive on the surface of the polishing pad 100.

Examples of the material of the polishing cloth 100 include polyurethane, polyester fiber, and fluorocarbon. The thickness T10 of the polishing pad 100 is, for example, 15 mm or less, and preferably 5 mm or less.

FIG. 3 shows a schematic diagram of the cross-sectional shape of the groove 110.

The cross-sectional shape of the groove 110 is not particularly limited, and examples thereof include a rectangle (see (a)), a V-shape (see (b)), a semicircle (see (c)), a U-shape, and the like. be able to. The width W10 and the depth D10 of the groove 110 are not particularly limited.
The depth D10 of the groove 110 is, for example, 0.1 to 15 mm, and preferably 0.1 to 1.5 mm. As a method of forming the groove 110, for example, a method using a milling machine, a lathe, a press, or the like can be given.

The features of this embodiment are mainly as follows.

That is, the plurality of grooves 110 are formed concentrically, and are formed such that the density of the groove pattern decreases from the center to the outer periphery. That is, the amount of the abrasive retained per unit area on the surface of the polishing cloth 100 is reduced from the center to the outer periphery.

When the polishing cloth 100 according to the present embodiment is used to polish a wafer, for example, the uniformity of the polishing rate within the wafer surface can be easily controlled only by adjusting the position of the wafer. Can be. For example, by adjusting the position of the wafer as described below, the uniformity of the polishing rate within the wafer surface can be easily controlled.

When the wafer is polished, in the surface region of the polishing pad 100 having a large abrasive holding amount per unit area (the central portion of the polishing pad), a portion of the wafer to which the polishing agent hardly spreads (for example, the wafer). (The central part) is polished. At the same time, in the surface region of the polishing pad 100 having a small amount of the polishing agent held per unit area (the outer peripheral portion of the polishing pad), mainly, the portion of the wafer (for example, the outer peripheral portion of the wafer) where the abrasive is easily spread is polished. So that As described above, if the position of the wafer is adjusted and the wafer is polished, the uniformity of the polishing rate within the wafer surface can be easily improved. As a result, the uniformity of the polishing amount in the wafer surface can be easily and easily achieved.

In the present embodiment, the interval S10 between the grooves 110 is gradually increased from the center to the outer periphery. However, the grooves 110 may be formed at equal intervals in some regions. For example, in regions (A), (B) and (C) in FIG.
The interval S10 between the grooves 110 is the same in the same region,
In addition, a mode in which the interval S10 is gradually increased from the area (A) to the area (C) may be adopted.

(Second Embodiment) FIG. 4 is a plan view schematically showing a polishing pad according to a second embodiment. FIG. 5 shows regions (A), (B) and (C) of the polishing cloth of FIG.
5 is a schematic cross-sectional view of FIG. 5, wherein the centers of the regions (A), (B) and (C) are located on a line connecting one point on the outer periphery from the center of the polishing pad.

A polishing cloth 200 according to the second embodiment
Differs from the first embodiment in that the depth D10 of the groove is made non-uniform. For other configurations,
Since the third embodiment is substantially the same as the first embodiment, a detailed description thereof will be omitted.

On the surface of the polishing pad 200 according to this embodiment, a plurality of grooves 210 are formed concentrically at equal intervals. These grooves 210 are formed such that the depth D10 of the grooves 210 decreases gradually from the center toward the outer periphery (from the region (A) to (C)).

The groove 210 has a function of holding an abrasive on the surface of the polishing cloth 200. The presence of this abrasive on the surface of the polishing pad 200 facilitates polishing.

Although the depth D10 of these grooves 210 is not particularly limited, for example, 0.1 to 15 mm,
Preferably it is 0.1 to 1.5 mm. Width W of groove 210
10 is not particularly limited, and is, for example, 0.1 to 10 mm. The material and thickness of the polishing pad 200 are not particularly limited, and examples thereof include those similar to those of the first embodiment. The cross-sectional shape of the groove 210 is not particularly limited,
For example, the shape shown in the first embodiment (see FIG. 3) can be used.

The features of this embodiment are mainly as follows.

That is, the plurality of grooves 210 are formed concentrically, and the depth D10 of the grooves 210 is gradually reduced from the center to the outer periphery. That is, the amount of the abrasive held per unit area on the surface of the polishing pad 200 is reduced from the center to the outer periphery.

When the polishing cloth 200 according to the present embodiment is used to polish a wafer, for example, it is possible to easily control the uniformity of the polishing rate within the wafer surface only by adjusting the position of the wafer. Can be. For example, by adjusting the position of the wafer as described below, the uniformity of the polishing rate within the wafer surface can be easily controlled.

When the wafer is polished, in the surface region of the polishing pad 200 having a large abrasive holding amount per unit area (portion on the center side of the polishing pad), a portion of the wafer (for example, wafer (The central part) is polished. Further, in the surface region of the polishing pad 200 having a small amount of the abrasive held per unit area (the outer peripheral side portion of the polishing pad), mainly, the portion of the wafer (for example, the outer peripheral portion of the wafer) where the abrasive easily flows is polished. So that As described above, if the position of the wafer is adjusted and the wafer is polished, the uniformity of the polishing rate within the wafer surface can be easily improved. As a result, the uniformity of the polishing amount in the wafer surface can be easily and easily achieved.

In the present embodiment, the depth of the groove 210 is gradually reduced from the center to the outer periphery. However, the surface area of the polishing cloth 200
A region where the depths D10 of the adjacent grooves 210 are the same as each other may be partially included. For example, in regions (A), (B) and (C) in FIG.
May be the same in the same region, and the depth D10 of the groove 210 may be gradually reduced from the region (A) to the region (C).

(Third Embodiment) FIG. 6 is a plan view schematically showing a polishing pad according to a third embodiment. FIG. 7 shows regions (A), (B) and (C) of the polishing cloth of FIG.
, The centers of the regions (A), (B) and (C) are located on a line connecting one point of the outer periphery from the center of the polishing pad.

A polishing cloth 300 according to the third embodiment
Differs from the first embodiment in that the width W10 of the groove 310 is made non-uniform. For other configurations,
Since it is substantially the same as the first embodiment, a detailed description is omitted.

On the surface of the polishing pad 300 according to the present embodiment, a plurality of grooves 310 are formed concentrically at equal intervals. Further, these grooves 310 are formed such that the width W10 of the grooves 310 is gradually reduced from the center toward the outer periphery (from the region (A) to (C)). That is, as the width W10 of the groove 310 is gradually reduced, the occupied area of the groove 310 per unit area is reduced from the center toward the outer periphery.

The groove 310 has a function of holding an abrasive on the surface of the polishing cloth 300. The polishing is promoted by the presence of the abrasive on the surface of the polishing cloth.

The width W10 of these grooves 310 is not particularly limited, but is preferably in the range of 0.1 to 15 mm. The depth of the groove 310 is not particularly limited, and is, for example, 0.1 to 15 mm, preferably 0.1 to 15 mm.
1.5 mm. The material and thickness of the polishing cloth 300
There is no particular limitation, and for example, those similar to the first embodiment can be mentioned. The cross-sectional shape of the groove 310 is not particularly limited, and may be, for example, the shape shown in the first embodiment (see FIG. 3).

The features of this embodiment are mainly as follows.

That is, the plurality of grooves 310 are formed concentrically, and are formed such that the width W10 of the grooves 310 is gradually reduced from the center to the outer periphery. That is, from the center to the outer periphery, the surface of the polishing cloth 300
That is, the amount of the abrasive retained per unit area is reduced.

When the polishing cloth 300 according to the present embodiment is used to polish a wafer, for example, it is possible to easily control the uniformity of the polishing rate within the wafer surface only by adjusting the position of the wafer. Can be. For example, by adjusting the position of the wafer as described below, the uniformity of the polishing rate within the wafer surface can be easily controlled.

When polishing a wafer, in the surface region of the polishing pad 300 having a large abrasive holding amount per unit area (the central portion of the polishing pad), mainly the portion of the wafer where the abrasive is difficult to spread (for example, the wafer). (The central part) is polished. Further, in the surface region of the polishing pad 300 having a small amount of the abrasive held per unit area (the outer peripheral portion of the polishing pad), mainly, the portion of the wafer (for example, the outer peripheral portion of the wafer) where the abrasive easily flows is polished. So that As described above, if the position of the wafer is adjusted and the wafer is polished, the uniformity of the polishing rate within the wafer surface can be easily improved. As a result, it is possible to easily and easily equalize the amount of polishing within the wafer surface.

In the present embodiment, the width W10 of the groove 310 increases from the center toward the outer periphery.
It is gradually narrowing. However, the surface region of the polishing pad 200 may partially include a region where the width W10 of the adjacent groove 310 is the same as each other. For example, in the regions (A), (B) and (C) in FIG.
The width W10 of the groove 310 may be the same in the same region, and the width W10 of the groove 310 may be gradually reduced from the region (A) to the region (C).

(Fourth Embodiment) A polishing apparatus using a polishing cloth according to the present invention will be described below.

(Polishing Apparatus) FIG. 8 is a schematic view of a polishing apparatus according to the fourth embodiment.

The polishing apparatus 400 according to the present embodiment
Polishing section 410, polished section 420, abrasive supply means 4
30.

The polishing section 410 has a polishing table 412, a rotating shaft 414, and a rotation drive mechanism (not shown). The polishing platen 412 and the rotation drive mechanism are connected by a rotation shaft 414. The polishing platen 412 is driven to rotate by a rotation driving mechanism via a rotation shaft 414. Polishing surface plate 4
The polishing cloth 440 according to the present invention is mounted on the upper surface of the polishing pad 12.

The polished portion 420 is provided at a position facing the polishing platen 412. The portion to be polished 420 includes a rotating platen 422, a rotating shaft 426, and a pressing and rotating driving mechanism 42.
And 4. Rotary surface plate 422 and pressure / rotation drive mechanism 4
24 is connected by a rotation shaft 426. The rotating platen 422 is driven to rotate by a pressurizing / rotating drive mechanism 424 via a rotating shaft 426. A holding mechanism (not shown) for holding the material to be polished 450 is provided at an end of the rotary platen 422 on the side of the polishing section 410. Examples of the holding mechanism include a vacuum suction holding mechanism, a mechanical holding mechanism (using a plurality of levers), and a holding mechanism using surface tension. With this holding mechanism, the material to be polished 450 is attached to the end of the rotary platen 422.

The abrasive supply means 430 includes a polishing platen 412
Is provided at a position opposite to the above. Abrasive supply means 43
By 0, the abrasive is supplied onto the polishing cloth 440.

(Operation) First, a polishing cloth 440 is attached to the upper surface of the polishing platen 412. Also, a material to be polished 450 is attached to an end of the rotary platen 422. Examples of the material to be polished 450 include a wafer such as a silicon substrate and a glass substrate.

Next, the polishing platen 412 is driven to rotate by the rotation driving mechanism. The polishing agent is supplied to the surface of the polishing pad 440 by the polishing agent supply means 430, and the polishing agent is spread over the entire surface of the polishing pad 440. Examples of the abrasive include a slurry and the like.

The rotary platen 422 is pressed and rotated by the drive mechanism 42.
While rotating by 4, the workpiece 450 is pressed against the polishing pad 440. The pressing and rotating drive mechanism 424 causes the polishing target material 4 between the polishing pad 440 and the rotary platen 422 to be polished.
Polishing of the material to be polished 450 is performed while pressing 50.

After polishing the workpiece 450, the workpiece 4
50 is separated from the polishing pad 440, and the supply of the abrasive is stopped. Thereafter, the workpiece 450 is detached from the rotary platen 422 and washed to remove the abrasive attached to the surface of the workpiece 450.

A characteristic feature of the polishing apparatus according to the present embodiment is that the polishing cloth of the present invention is used as a polishing cloth. Thus, when a wafer is polished using this polishing apparatus, for example, as described in the first to third embodiments, only by adjusting the polishing position of the wafer, the wafer surface of the polishing rate can be easily adjusted. The uniformity in the inside can be controlled. As a result, the uniformity of the polishing amount in the wafer surface can be easily and easily achieved.

Hereinafter, an example of a method for determining a wafer polishing position in the polishing apparatus according to the present embodiment will be described.

(Method of Determining Wafer Polishing Position) (1) The thickness of the film to be polished formed on the wafer is measured.

(2) Determine a reference position (for example, the middle point of a straight line connecting the center of the polishing pad and one point on the outer periphery).

(3) The wafer is placed on the polishing pad at a position where the center of the wafer overlaps the reference position.

(4) Polish the wafer.

(5) The thickness of the film to be polished after polishing is measured. Then, the polishing rate is calculated by subtracting the thickness of the polishing target film after polishing from the thickness of the polishing target film before polishing, and the in-plane tendency of the polishing rate is obtained.

(6) Based on the in-plane tendency of the polishing rate,
Move the wafer. This movement is divided into the following two depending on the difference between the polishing rate at the outer peripheral portion of the wafer and the polishing rate at the central portion of the wafer.

1) When the polishing rate at the outer peripheral portion of the wafer is higher than the polishing rate at the central portion of the wafer, the wafer is moved so that the center of the wafer is located on the outer peripheral side from the reference position (for example, about 1 cm).

Hereinafter, the reason for moving the wafer will be described. The more the polishing cloth is located on the outer peripheral side, the smaller the amount of the abrasive retained. In addition, when the holding amount of the polishing agent is reduced, the wafer is harder to be cut by that much. Therefore, in the above case, the polishing rate of the outer peripheral portion of the wafer can be reduced by positioning the center of the wafer on the outer peripheral side from the reference position. As a result, the difference between the polishing rate at the center of the wafer and the polishing rate at the outer periphery can be further reduced.

2) If the polishing rate of the outer peripheral portion of the wafer is lower than the polishing rate of the central portion of the wafer, the wafer is moved so that the center of the wafer is located closer to the center than the reference position (for example, about 1 cm).

Hereinafter, the reason for moving the wafer in this manner will be described. The closer to the center of the polishing cloth, the greater the amount of the abrasive retained. Also, when the holding amount of the polishing agent increases, the wafer is more likely to be shaved. For this reason, in the above case, the polishing rate of the outer peripheral portion of the wafer can be increased by setting the center of the wafer closer to the center side than the reference position. As a result, the difference between the polishing rate at the center of the wafer and the polishing rate at the outer periphery can be further reduced.

(7) The cycle of (4) to (6) is repeated to determine the polishing position of the wafer at which the uniformity of the polishing rate in the wafer surface is the best.

Using the polishing cloth of the present invention, as described above,
By positioning the wafer, for example, the following effects are obtained.

FIG. 9 is a graph showing the relationship between the position of the wafer in the wafer plane and the polishing rate. This polishing was performed under the following conditions. A polishing cloth outside the technical scope of the present invention was used as the polishing cloth. That is, as the polishing cloth, one having grooves formed concentrically at equal intervals on the surface of the polishing cloth and having the same width and depth was used. Polishing was performed within a pressure range of 15 to 60 kPa (pressure applied to the wafer between the polishing pad and the rotary platen).

As is clear from FIG. 9, when polishing is performed using the above-described polishing cloth, the polishing rate becomes lower toward the center of the wafer, and the polishing rate in the wafer surface becomes lower. It turns out that it is uniform.

However, using the polishing cloth of the present invention,
By performing the positioning as described above, it is possible to eliminate the non-uniformity of the polishing rate in the wafer surface as shown in FIG.

The polishing apparatus according to the fourth embodiment can be applied to the following method for manufacturing a semiconductor device.

(Fifth Embodiment) Hereinafter, an example of a method for manufacturing a semiconductor device having a multilayer wiring layer using the polishing apparatus according to the present invention will be described.

FIGS. 10 to 13 are cross-sectional views schematically showing steps of manufacturing a semiconductor device having a multilayer wiring layer.

First, a description will be given with reference to FIG. By a general method, a MOSFET is formed on the surface of the substrate 410.
, An element isolation region, a semiconductor element, a wiring layer (all not shown), and the like are formed. A first interlayer insulating layer 420 having a contact hole (not shown) is formed on a substrate 410 by a known method. First interlayer insulating layer 4
A first wiring layer 430 is formed on the substrate 20 so as to fill the contact hole, and the first wiring layer 430 is patterned by a known method.

Next, as shown in FIG. 11, a second interlayer insulating layer 440 is formed on the first wiring layer 430.

Next, as shown in FIG. 12, the second interlayer insulating layer 4 is formed by the CMP method using the polishing apparatus according to the present invention.
40 is flattened.

Next, as shown in FIG. 13, through holes 442 are formed in second interlayer insulating layer 440 such that predetermined portions of the surface of first wiring layer 430 are exposed. Then, the through hole 44 is formed on the second interlayer insulating layer 440.
The second wiring layer 450 is formed so as to fill the second wiring layer 450.
Next, by patterning the second wiring layer 450, a semiconductor device 500 having a multilayer wiring layer is formed.

A characteristic point of the above-described method for manufacturing a semiconductor device is that the interlayer insulating layer is planarized by the CMP method using the polishing apparatus according to the present invention. By planarizing the interlayer insulating layer using the polishing apparatus according to the present invention, the surface of the interlayer insulating layer can be planarized with high accuracy due to the features of the polishing apparatus. By forming a wiring layer on the thus flattened interlayer insulating layer, problems such as disconnection of the wiring layer do not occur.

The polishing apparatus according to the present invention can be applied not only to the above-described method for manufacturing a semiconductor device but also to, for example, the following method for manufacturing a semiconductor device.

(1) A method of manufacturing a semiconductor device including a step of forming a multilayer wiring layer utilizing a damascene method. Here, the step of forming a multilayer wiring layer using the damascene method includes forming a metal layer on an insulating layer having a through hole, polishing the metal layer and flattening the metal layer, thereby forming the inside of the through hole. This is a step of forming a buried metal layer.

(2) A method of manufacturing a semiconductor device including a step of polishing a metal or nonmetal (for example, silicon) film formed on a silicon substrate.

(3) A method of manufacturing a semiconductor device including a step of polishing a surface of a silicon substrate.

(4) A method for manufacturing a semiconductor device having a multilayer wiring structure, including a step of flattening a first or second or more interlayer insulating layer or a metal wiring layer.

According to the method of manufacturing a semiconductor device as described above, miniaturization and high integration of the semiconductor device can be achieved.

(Modifications) The above embodiments can be variously modified without departing from the gist of the present invention. For example, the following changes are possible.

(1) The mode of the groove of the polishing pad may be a mode in which at least two of the features relating to the groove of the polishing pad according to the first to third embodiments are combined. Specifically, for example, the following four aspects can be cited. FIG. 14 is a cross-sectional view schematically showing a cross section of a polishing cloth according to a modification.

First, as shown in FIG. 14A, this is an aspect in which the features of the first embodiment and the second embodiment relating to the polishing pad are combined. Hereinafter, this modified example will be specifically described. The polishing pad 600 of this modification includes:
As in the first and second embodiments, a plurality of grooves 610 are provided.
Are formed concentrically (a plan view is omitted). These grooves 610 are formed such that the distance S10 between the grooves 610 increases gradually from the center to the outer periphery. These grooves 610 are formed such that the depth D10 of the grooves gradually decreases from the center to the outer periphery.

Second, as shown in FIG. 14 (b), an aspect in which the features of the first embodiment and the third embodiment relating to the polishing pad are combined. Hereinafter, this modified example will be specifically described. The polishing pad 700 of this modification includes:
As in the first and third embodiments, a plurality of grooves 710 are provided.
Are formed concentrically (a plan view is omitted). These grooves 710 are formed such that the distance S10 between the grooves 710 increases gradually from the center to the outer periphery. In addition, these grooves 710 have a width W10 of the groove 710 from the center to the outer periphery.
Are formed so as to gradually narrow.

Third, as shown in FIG. 14 (c), this is an aspect in which the features of the second embodiment and the third embodiment relating to the polishing pad are combined. Hereinafter, this modified example will be specifically described. The polishing pad 800 of this modification includes:
As in the second and third embodiments, the plurality of grooves 810
Are formed concentrically (a plan view is omitted). These grooves 810 are formed such that the depth D10 of the grooves 810 decreases gradually from the center to the outer periphery. Further, these grooves 810 are formed such that the width W10 of the grooves 810 is gradually reduced from the center to the outer periphery.

Fourthly, as shown in FIG. 14 (d), this is an aspect in which the feature points of the polishing cloth in the first to third embodiments are combined. Hereinafter, this modified example will be specifically described. The polishing pad 900 of this modification has a plurality of grooves 910 formed concentrically (a plan view is omitted). The configuration of the interval S10 between the grooves 910 and the depth D10 of the groove 910 is the same as the above configuration. Further, these grooves 910 are formed such that the width W10 of the grooves 910 decreases gradually from the center to the outer periphery.

(2) In the first to third embodiments, the grooves are applied as the concave portions, and the plurality of grooves are formed concentrically. However, the present invention is not limited to this mode, and any mode may be used as long as the concave portion is formed so that the amount of the abrasive retained per unit area on the surface of the polishing cloth decreases from the center toward the outer periphery. For example,
In addition to the above-described embodiment, the following aspects can be cited as aspects of the recess. (1) As shown in FIG.
In this embodiment, a plurality of grooves 1110 are provided so as to extend along the direction (direction), and a plurality of grooves 1120 are provided so as to extend along a direction intersecting these grooves (for example, the Y direction). (2) As shown in FIG.
00 is the embodiment formed. (3) As shown in FIG. 15C, the groove 1300 is formed in a spiral shape.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a polishing cloth according to a first embodiment.

FIG. 2 is a schematic cross-sectional view of (A), (B) and (C) of FIG.

FIG. 3 is a schematic diagram of a cross-sectional shape of a groove formed in the polishing pad according to the first embodiment.

FIG. 4 is a plan view schematically showing a polishing cloth according to a second embodiment.

FIG. 5 is a schematic cross-sectional view of (A), (B) and (C) of FIG.

FIG. 6 is a plan view schematically showing a polishing cloth according to a third embodiment.

FIG. 7 is a schematic sectional view in (A), (B) and (C) of FIG. 6;

FIG. 8 is a schematic view of a polishing apparatus according to a fourth embodiment.

FIG. 9 is a graph showing a relationship between a position of a wafer in a wafer surface and a polishing rate.

FIG. 10 is a sectional view schematically showing steps of a method for manufacturing a semiconductor device according to a fifth embodiment.

FIG. 11 is a sectional view schematically showing steps of a method for manufacturing a semiconductor device according to a fifth embodiment.

FIG. 12 is a sectional view schematically showing steps of a method for manufacturing a semiconductor device according to a fifth embodiment.

FIG. 13 is a cross-sectional view schematically showing steps of a method for manufacturing a semiconductor device according to the fifth embodiment.

FIG. 14 is a cross-sectional view schematically showing a cross section of a polishing cloth according to a modification.

FIG. 15 is a plan view schematically showing a modification of the mode of the groove formed on the surface of the polishing pad.

[Explanation of symbols]

 100, 200, 300 Polishing cloth 110, 210, 310 Groove 400 Polishing device 500 Semiconductor device S10 Spacing between grooves D10 Groove depth W10 Groove width

Claims (15)

[Claims] 1. A polishing cloth including a surface region having at least one concave portion for holding an abrasive, wherein the concave portion has a polishing agent holding amount per unit area on a surface of the polishing cloth. A polishing cloth formed so as to decrease in size from the center to the outer periphery of the polishing cloth. 2. The polishing pad according to claim 1, wherein the concave portion has a groove shape or a dot shape. 3. The polishing cloth according to claim 1, wherein the plurality of recesses are formed in the surface region, and the plurality of recesses are formed in a groove shape and concentrically. 4. The polishing cloth according to claim 1, wherein an occupied area of the concave portion per unit area decreases from a central portion to an outer peripheral portion of the polishing cloth. 5. The polishing pad according to claim 4, wherein the number of the concave portions per unit area decreases from a central portion to an outer peripheral portion of the polishing pad. 6. The polishing cloth according to claim 4, wherein the width of the recess decreases from the center to the outer periphery of the polishing cloth. 7. The polishing cloth according to claim 4, wherein the number of the recesses per unit area decreases from the center of the polishing cloth toward the outer periphery, and the width of the recesses is the center of the polishing cloth. A polishing cloth that becomes narrower as it goes to the outer periphery. 8. The concave part according to claim 1, wherein the concave part is formed such that a depth of the concave part becomes shallower from a central part of the polishing pad toward an outer peripheral part.
Polishing cloth. 9. The polishing pad according to claim 1, wherein the recess is formed by combining the following aspects (a) and (b). (A) an embodiment in which the recess is formed such that the area occupied by the recess per unit area on the surface of the polishing cloth decreases from the center to the outer periphery of the polishing cloth; b) A mode in which the recess is formed such that the depth of the recess decreases from the center to the outer periphery of the polishing pad. 10. The method according to claim 9, wherein in the aspect (a), the number of the concave portions per unit area is:
The polishing, which is at least one of a mode in which the width decreases from the center of the polishing cloth toward the outer periphery and a width in which the width of the recess decreases from the center of the polishing cloth toward the outer periphery. cloth. 11. A polishing apparatus comprising: polishing means for rubbing a polishing cloth and a material to be polished; and abrasive supply means for supplying a polishing agent to the surface of the polishing cloth. Item 11. A polishing apparatus, which is the polishing cloth according to any one of Items 1 to 10. 12. A method of manufacturing a semiconductor device including a step of polishing a semiconductor wafer, wherein the step of polishing the semiconductor wafer is performed by using the polishing apparatus according to claim 11. . 13. The polishing pad according to claim 12, further comprising a step of determining a polishing position of the semiconductor wafer with respect to the polishing cloth according to claim 1. The step of determining includes a step of polishing a test semiconductor wafer, and in the step of polishing the test semiconductor wafer, a polishing position of the semiconductor wafer is determined based on a polishing rate in a polishing surface of the test semiconductor wafer. The semiconductor device manufacturing method to be determined. 14. The polishing method according to claim 13, wherein in the step of polishing the test semiconductor wafer, a polishing rate of an outer peripheral portion of the test semiconductor wafer is higher than a polishing rate of a central portion of the test semiconductor wafer. The step of polishing the semiconductor wafer is performed by positioning the center of the semiconductor wafer on the outer peripheral side of the polishing cloth from the position of the polishing cloth on which the center of the test semiconductor wafer is polished; Manufacturing method. 15. The polishing method according to claim 13, wherein in the step of polishing the test semiconductor wafer, a polishing rate of an outer peripheral portion of the test semiconductor wafer is lower than a polishing rate of a central portion of the test semiconductor wafer. A step of polishing the semiconductor wafer, wherein a center of the semiconductor wafer is positioned closer to a center of the polishing cloth than a position of the polishing cloth where the center of the test semiconductor wafer is polished, Manufacturing method.