JP2001079755A - Abrasive body and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve polishing characteristics such as homogeneity and flatness by forming many different kinds of irregular structures periodically or nonperiodically on the surface of an abrasive. SOLUTION: The pressure per unit area applied to an abrasive body is small in the region where the width of the lugs of the irregular structure of the abrasive body is wide, and the deformation quantity of the abrasive body caused by the pressure is small. The pressure per unit area applied to the abrasive body is large in the region where the width of the lugs of the irregular structure of the abrasive body is narrow, and the deformation quantity of the abrasive body caused by the pressure is large. The portion where the width of the lugs of the irregular structure of the abrasive body is wide functions in the same way as the hard abrasive body and selectively polishes the lugs of the irregular pattern on a silicon wafer when polishing the irregular pattern, and homogeneity is improved. The portion where the width of the lugs of the irregular structure of the abrasive body is narrow functions in the same way as the soft abrasive body and polishes the lugs by following the warp of the silicon wafer or film thickness irregularities at film formation, and flatness is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a polishing body and a polishing method used in a polishing apparatus suitable for use in flattening polishing of a semiconductor device performed in a process of manufacturing a semiconductor device such as an ULSI. .

[0002]

2. Description of the Related Art As the degree of integration and miniaturization of a semiconductor integrated circuit increases, the steps of a semiconductor manufacturing process are increasing and becoming more complicated. Along with this, the surface of the semiconductor device is not necessarily flat. The presence of a step on the surface of a semiconductor device causes disconnection of wiring, an increase in local resistance, and the like, resulting in disconnection and a decrease in electric capacity. In addition, in the case of an insulating film, withstand voltage degradation and leakage may occur.

On the other hand, as semiconductor integrated circuits become more highly integrated and miniaturized, the wavelength of a light source of a semiconductor exposure apparatus used for optical lithography becomes shorter, and the numerical aperture of a projection lens of the semiconductor exposure apparatus, so-called NA, becomes larger. It has become to. Thereby, the depth of focus of the projection lens of the semiconductor exposure apparatus is
It is getting shallower in nature. In order to cope with a shallower depth of focus, the surface of a semiconductor device needs to be flatter than ever.

More specifically, in a semiconductor manufacturing process, a flattening technique as shown in FIGS. 5A and 5B has become essential. 5A and 5B are conceptual diagrams of a planarization technique in a semiconductor manufacturing process, and are cross-sectional views of a semiconductor device. 5A and 5B, 21 is a silicon wafer, 22 is an interlayer insulating film made of SiO ₂ , 23 is a metal film made of Al, and 24 is a semiconductor device.

FIG. 5A shows an example in which an interlayer insulating film 22 on the surface of a semiconductor device is flattened. FIG. 5B shows an example in which the metal film 23 on the surface of the semiconductor device is polished to form a so-called damascene. As a method of flattening the surface of such a semiconductor device, there is known a chemical mechanical polishing (Chemical Mechanical Polishing or Chemi
cal Mechanical Planarization (hereinafter referred to as CMP)) is widely used. At present, the CMP technique is the only method that can planarize the entire surface of a silicon wafer.

The CMP has been developed based on a mirror polishing method for a silicon wafer, and is performed using a CMP apparatus as shown in FIG. In FIG. 6, reference numeral 131 denotes a polishing member;
2 is a polishing object holding portion (hereinafter, referred to as a polishing head),
133 is a silicon wafer to be polished, 134 is an abrasive supply unit, and 135 is an abrasive. Polishing member 131
Is obtained by attaching a polishing body 137 on a polishing platen 136. As a polishing body, sheet-like foamed polyurethane is often used.

An object 133 to be polished is held by a polishing head 132 and oscillates while rotating, so that a polishing member 131 is rotated.
At a predetermined pressure. The polishing member 131 is also rotated to cause relative movement between the polishing objects 133. In this state, the abrasive 135 is supplied from the abrasive supply unit 134 onto the abrasive body 137, and the abrasive 135 diffuses on the abrasive body 137, and moves along with the relative movement between the abrasive member 131 and the object 133. 137 and polishing object 1
33, and polishes the polished surface of the object 133 to be polished. That is, the mechanical polishing by the relative movement between the polishing member 131 and the polishing object 133 and the chemical action of the polishing agent 135 act synergistically to perform good polishing.

For the polished silicon wafer (object to be polished), polishing characteristics such as uniformity and flatness are very important. The uniformity is to evaluate whether the polishing is performed uniformly over the entire area of the silicon wafer. Then, the polishing amount profile of the polished surface of the polished silicon wafer is measured, and the uniformity is generally obtained by the following equation.

[0009] Uniformity (%) = (RA-RI) / (RA +
RI) × 100 Here, RA is the maximum polishing amount in the measured polishing amount profile, and RI is the minimum polishing amount in the measured polishing amount profile. The smaller the value of uniformity obtained from the above equation, the better the characteristics. That is, the smaller the difference between the maximum polishing amount and the minimum polishing amount, the better the uniformity of polishing in the entire region of the silicon wafer.

[0010] The flatness indicates the size of the residual step of the concavo-convex pattern when the silicon wafer having the concavo-convex pattern is polished. In other words, the flatness indicates how much a convex portion is selectively polished by polishing in a silicon wafer having a concavo-convex pattern, and the residual step of the concavo-convex pattern after polishing is reduced. As for the flatness, the smaller the value is, the better the characteristics are.

[0011] Both polishing properties of uniformity and flatness are greatly affected by the elastic modulus of the polished body. The abrasive body is classified into a soft abrasive body having a small elastic modulus and a hard abrasive body having a large elastic modulus according to the magnitude of the elastic modulus. In the case of a soft polishing body having a small elastic modulus, when pressure is applied to the silicon wafer, the surface of the polishing body has a very high adhesion to the warpage of the silicon wafer, and the uniformity is very good over the entire surface of the silicon wafer. Become. However, with respect to a silicon wafer having an uneven pattern, the polishing body follows the unevenness on the silicon wafer due to the deformation of the polishing body, and the polishing proceeds while the steps remain, so that the flatness deteriorates.

On the other hand, in the case of a hard abrasive having a large elastic modulus,
As for the silicon wafer having the uneven pattern, since the polishing body is less deformed, it is polished sequentially from the convex portion of the uneven pattern, and the flatness is good. However, since the warpage of the silicon wafer and the pressure distribution at the time of pressing directly affect the polishing, the uniformity deteriorates. That is, in both the soft polished body and the hard polished body, improvement in uniformity and improvement in flatness are not compatible, and there is a trade-off relationship between both uniformity and flatness.

Recently, in order to satisfy both of these polishing characteristics, a polishing body having a laminated structure in which a lower layer having a large elastic modulus and an upper layer having a small elastic modulus are laminated has been used, and the pressing method of the polishing head has been improved. A polishing head or the like of a fluid pressurized method is used, and aims at both improvement of uniformity and improvement of flatness.

[0014]

However, in a polishing body having a laminated structure, there is a problem that a difference in polishing characteristics due to a variation in the polishing body itself becomes large, and an unstable factor becomes large from the viewpoint of a semiconductor manufacturing process. . Further, the improvement of the polishing head has a problem that the structure of the polishing head becomes very complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a polishing body exhibiting excellent characteristics in both uniformity and flatness even in a conventional polishing apparatus, and a polishing method using the same. The purpose is to:

[0016]

In view of the above problems, the present inventors have found that by forming two or more types of uneven structures on the surface of a polishing body, both uniformity and flatness are excellent. Reached. That is, in order to solve the above-described problem, the polishing body according to the present invention, in a state where the abrasive is interposed between the polishing body and the polishing object, by relatively moving the polishing body and the polishing object by In a polishing body used in a polishing apparatus for polishing the object to be polished, two or more different types of uneven structures are periodically or aperiodically formed on the surface (claim 1).

According to the above-mentioned polishing body, since two or more types of uneven structures are formed, a portion having good uniformity and a portion having good flatness among polishing characteristics coexist due to the uneven structure. Thereby, both uniformity and flatness are improved. In addition, in the region where the same type of the concavo-convex structure is formed, it is preferable that two or more concave portions of the concavo-convex structure and two or more convex portions of the concavo-convex structure are formed (claim 2). Thereby, the uniformity and flatness are further improved.

The concave-convex structure includes two types of concave-convex structures, a first concave-convex structure and a second concave-convex structure. The concave portion of the first concave-convex structure and the concave portion of the second concave-convex structure are:
Groove, and the width of the protrusion of the first uneven structure is the second width.
It is at least twice as large as the width of the projection of the uneven structure (claim 3).
As a result, the region of the polishing body in which the first uneven structure having a large convex portion is formed functions similarly to the hard abrasive body, and selectively forms the uneven pattern when polishing the object to be polished having the uneven pattern. By polishing the convex portions, the uniformity is improved. On the other hand, the region of the polishing body in which the second concave-convex structure in which the width of the convex portion is small functions similarly to the soft polishing body,
Polishing follows the warpage of the object to be polished and the film thickness unevenness of the film formed on the surface of the object to be polished, thereby improving the flatness.

It is preferable that the regions having a circular shape and the same type of the concavo-convex structure are arranged concentrically (claim 4). Thereby, the uniformity and flatness are further improved. Further, it is preferable that the regions where the same type of the concavo-convex structure is formed are arranged in a lattice shape. Thereby, the uniformity and flatness are further improved.

Preferably, a groove for supplying and discharging the abrasive is further formed on the surface. As a result, the polishing agent is uniformly supplied to the entire surface of the object to be polished, so that the uniformity is not deteriorated and the friction is not increased, so that the characteristics of the polishing apparatus are not deteriorated. Also,
Vickers hardness k is 2.5 (Kg / mm ² ) <k <30 (Kg
/ Mm ² ) (claim 7). Thereby, the uniformity and flatness are further improved.

Further, the first layer has the uneven structure formed on the surface thereof, and the second layer is laminated on the first layer. The elastic modulus of the second layer is as follows. It is preferable that the elastic modulus of the first layer is larger than that of the first layer. This makes it possible to improve the uniformity and flatness of the polishing body having a laminated structure. Further, in order to solve the above-mentioned problem, the polishing method according to the present invention, in a state where an abrasive is interposed between the polishing body and the polishing object, by relatively moving the polishing body and the polishing object by In the polishing method for polishing an object to be polished, the object to be polished is a silicon wafer on which semiconductor devices are formed, and the polished body according to the present invention is used (claim 9).

According to the above-mentioned polishing method, 2
Since more than three types of uneven structures are formed, a part having good uniformity and a part having good flatness coexist in the polishing characteristics due to the uneven structure. Thereby, in the method of polishing a silicon wafer on which semiconductor devices are formed, both uniformity and flatness are improved.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are views showing a polishing body according to a first embodiment of the present invention. FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. The polishing body according to the first embodiment of the present invention has a circular shape, and has two types of uneven structures on the surface. Here, each of the two types of uneven structures is referred to as a first uneven structure and a second uneven structure. As shown in FIG. 1A, a region having a first uneven structure (black portion in FIG. 1A) and a region having a second uneven structure (white portion in FIG. 1A) are polished bodies. Are arranged concentrically on the surface of the. Region where the first uneven structure is formed (FIG. 1A)
Black portions) are arranged in three places, and regions where the second uneven structure is formed (white portions in FIG. 1A)
Are located in two places. In the region where the first concave-convex structure is formed, two or more concave portions and convex portions are formed, and even in the region where the second concave-convex structure is formed, two concave portions and two convex portions are formed. The above is formed. The concave portion of the first concave-convex structure and the concave portion of the second concave-convex structure are both grooves. These grooves are formed concentrically or spirally. Then, as shown in FIG. 1B, the width of the convex portion of the first concave-convex structure is different from the width of the convex portion of the second concave-convex structure, and the width of the convex portion of the first concave-convex structure is The width is larger than the width of the projection of the second uneven structure.

FIGS. 2A and 2B are views showing a polishing body according to a second embodiment of the present invention. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. 2A. The polishing body according to the second embodiment of the present invention has a circular shape, and has two types of uneven structures on the surface. Here, each of the two types of uneven structures is referred to as a first uneven structure and a second uneven structure. As shown in FIG. 2A, a region having the first uneven structure (black portion in FIG. 2A) and a region having the second uneven structure (white portion in FIG. 2A) are polished bodies. Are arranged in a grid pattern on the surface of the.
In the region where the first concave-convex structure is formed, two or more concave portions and convex portions are formed, and even in the region where the second concave-convex structure is formed, two concave portions and two convex portions are formed. The above is formed. The concave portion of the first concave-convex structure and the concave portion of the second concave-convex structure are both grooves. These grooves are linearly formed in each region along the vertical direction in FIG. Then, as shown in FIG. 2B, the width of the convex portion of the first concave-convex structure is different from the width of the convex portion of the second concave-convex structure, and the width of the convex portion of the first concave-convex structure is The width is larger than the width of the projection of the second uneven structure.

The polishing body according to the first embodiment or the second embodiment is mounted on a CMP apparatus and used for polishing a silicon wafer. Here, the CMP apparatus will be briefly described. The CMP apparatus includes a polishing member composed of a polishing plate attached with a polishing body, a polishing object holding section (hereinafter, referred to as a polishing head) for holding a silicon wafer as a polishing object, and polishing on the polishing body of the polishing member. And a polishing agent supply unit for supplying a polishing agent. The polishing head holding the silicon wafer swings while rotating, and is pressed against the polishing body of the polishing member at a predetermined pressure. The polishing member is also rotated to cause relative movement between the silicon wafers. In this state, the polishing agent is supplied onto the polishing body from the polishing agent supply unit, the polishing agent diffuses on the polishing body, and enters between the polishing body and the silicon wafer with the relative movement of the polishing member and the silicon wafer, The polishing surface of the silicon wafer is polished.

When a pressure is applied to the polishing head holding the silicon wafer and pressed against the polishing body according to the first embodiment or the second embodiment on the polishing platen at a predetermined pressure, In the region where the width of the protrusion of the uneven structure of the polishing body is wide,
The pressure per unit area applied to the polishing body is small, and the accompanying deformation of the polishing body is small. On the other hand, in a region where the width of the convex portion of the uneven structure of the polishing body is small, the pressure per unit area applied to the polishing body is large, and the deformation amount of the polishing body accompanying this is
large. That is, apparently, a hard abrasive and a soft abrasive coexist in the same abrasive.

A soft abrasive having a small elastic modulus has excellent uniformity, and a hard abrasive having a large elastic modulus has excellent flatness. This tendency also functions in the polishing body according to the present invention. That is, the wide portion of the convex portion of the uneven structure of the polishing body functions similarly to the hard polishing body, and by selectively polishing the convex portion of the uneven pattern on the silicon wafer at the time of polishing the uneven pattern. And the uniformity is improved. On the other hand, the narrow portion of the convex portion of the uneven structure of the polishing body functions in the same manner as the soft polishing body, and is polished following the warpage of the silicon wafer and the film thickness unevenness at the time of film formation. Thereby, the flatness is improved.

FIGS. 3A and 3B are views showing a polishing body according to a third embodiment of the present invention. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along the line CC ′ of FIG. 3A. The polishing body according to the third embodiment of the present invention is a modified example of the polishing body according to the first embodiment of the present invention.
The polishing body according to the third embodiment of the present invention is the first embodiment of the present invention.
The difference from the polishing body according to the embodiment is that a groove for supplying and discharging the abrasive is formed on the surface of the polishing body. In order to supply and discharge the abrasive, a straight groove 11 is formed radially from the center as shown in FIG. The other configuration is the same as that of the first embodiment, and the description is omitted.

FIGS. 4A and 4B are views showing a polishing body according to a fourth embodiment of the present invention. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along a line DD ′ in FIG. 4A. The polishing body according to the fourth embodiment of the present invention is a modified example of the polishing body according to the second embodiment of the present invention.
The polishing body according to the fourth embodiment of the present invention is the second embodiment of the present invention.
The difference from the polishing body according to the embodiment is that a groove for supplying and discharging the abrasive is formed on the surface of the polishing body. To supply and discharge the abrasive, a straight groove 12 is formed in the vertical direction and a straight groove 13 is formed in the horizontal direction as shown in FIG. Other configurations are the second
Since the third embodiment is the same as the first embodiment, the description is omitted.

In polishing a silicon wafer, it is desirable that the abrasive is uniformly supplied to the entire surface of the silicon wafer. If it is not supplied uniformly, the uniformity may be deteriorated, or the friction may be increased, and the characteristics of the polishing apparatus may be deteriorated. The grooves for supplying and discharging the abrasive of the polishing body according to the third embodiment and the fourth embodiment need only solve the above-described problems that occur during polishing.
The groove depth is not limited to any form.

In the polishing bodies according to the first, second, third and fourth embodiments, two types of uneven structures are used.
Three or more types of uneven structures may be used. The first,
In the polishing bodies according to the second, third, and fourth embodiments, the width of the concave portion and the width of the convex portion were constant in the region where the same type of uneven structure was formed. A concavo-convex structure in which the width of the convex portion changes in order may be used.

In the first and third embodiments, the first
The region having the uneven structure and the region having the second uneven structure are arranged concentrically. In the second and fourth embodiments, the region having the first uneven structure and the second uneven structure are different from each other. Are arranged in a lattice pattern,
The region having the concavo-convex structure and the region having the second concavo-convex structure may be periodically arranged, or may be arranged in other forms.

In the polishing bodies according to the first, second, third and fourth embodiments, the concave portions of the first concave-convex structure and the second concave-convex structure are grooves, but instead of the grooves, holes are formed. It may be. In the polishing bodies according to the first, second, third, and fourth embodiments, the groove of the concave portion of the first concave-convex structure is rectangular, and the groove of the concave portion of the second concave-convex structure is V-shaped. However, the shape of these grooves may be any of V-shaped, U-shaped, rectangular, and trapezoidal.

The polishing bodies according to the first, second, third and fourth embodiments are similarly applied to polishing bodies having a laminated structure with a layer having a large elastic modulus. in this case,
The polishing body having a laminated structure is composed of a first layer having an uneven structure on the surface and a second layer laminated on the lower surface of the first layer (the surface opposite to the surface). In order to obtain the effect of the present invention, the elastic modulus of the second
Is preferably larger than the elastic modulus of the layer.

Further, as a method of forming a groove on the surface of the polishing body, a known method, for example, a method of lathing the surface of the polishing body using a cutting tool can be used.
Hereinafter, embodiments of the present invention will be described with reference to examples.

[0036]

[Example 1] First polishing was performed on a polishing platen of a CMP apparatus.
A non-foamed abrasive body made of an epoxy resin and having a structure according to the embodiment (FIG. 1A) was attached. On the surface of the polished body, a concave-convex structure (a second concave-convex structure in FIG. 1B) having a V-groove having a depth of 0.3 mm and a convex portion having a width of 0.1 mm, A concavo-convex structure (a first concavo-convex structure in FIG. 1B) composed of a concave portion of 5 mm and a convex portion of 5 mm in width is formed concentrically at intervals of 20 mm. The angle of the slope of the V-shaped groove of the second uneven structure is about 60 °.

The Vickers hardness of the non-foamed abrasive made of epoxy resin is 7.0 (Kg / mm ² ). As described above, in order to obtain a structure in which the soft abrasive body and the hard abrasive body coexist, the Vickers hardness of the abrasive body is 2.5 (Kg / mm ² ).
As described above, it is preferably 30 (Kg / mm ² ) or less. In the first embodiment, the ratio of the width of the wide portion of the convex portion to the narrow portion of the convex portion in the concave-convex structure is 50 times. As described above, in order to have a structure in which the soft abrasive body and the hard abrasive body coexist, the ratio of the width of the wide portion of the convex portion to the narrow portion of the convex portion of the uneven structure is twice or more. Is preferred.

A 6-inch silicon wafer on which a thermal oxide film was formed at 1 μm was attached to the polishing head via a backing material, and polishing was performed under the following conditions. Number of rotations of the polishing head: 50 rpm, number of rotations of the polishing platen: 50 rpm, load (pressure for pressing the polishing head against the polishing body): 400 g / cm ² , oscillation width of the polishing head: 30 mm, oscillation speed of the polishing head: 1
5 strokes / minute, polishing time: 2 minutes, abrasive used: Cabo
t company SS25 diluted twice with ion exchange water, abrasive flow rate: 2
00 ml / min.

Further, for a 6-inch silicon wafer on which a plurality of 2 mm square convex patterns having a step of 500 nm (thickness of a convex portion is 1500 nm and thickness of a concave portion is 1000 nm) are formed by time management under the above conditions. 5 protrusions
It was polished to 00 nm. [Example 2] A non-foamed abrasive body having an epoxy resin and having a structure according to the third embodiment (FIG. 3A) was attached to a polishing platen of a CMP apparatus. In this abrasive body,
A radial groove 11 having a width of 2 mm and a depth of 0.3 mm is formed in advance to supply and discharge the abrasive. Furthermore, a V-groove having a depth of 0.3 mm and a width of 0.1 m were formed on the surface of the polished body.
The concave-convex structure composed of a convex portion having a height of m (the second concave-convex structure of FIG. 3B) and the concave-convex structure composed of a concave portion having a depth of 0.3 mm, a width of 5 mm, and a convex portion having a width of 5 mm (see FIG. First uneven structure)
They are arranged concentrically at intervals of 20 mm. The angle of the slope of the V-shaped groove of the second uneven structure is about 60 °.

Using this polished body, a 6-inch silicon wafer on which a thermal oxide film is formed at a thickness of 1 μm and a plurality of 2 mm square convex patterns having a plurality of steps of 500 nm are formed in the same manner as in Example 1. The inch silicon wafer was polished. Example 3 A non-foamed abrasive body having the structure according to the fourth embodiment (FIG. 4A) and made of epoxy resin was attached to a polishing platen of a CMP apparatus. In this foamable abrasive body, lattice-shaped grooves 12 and 13 having a width of 2 mm and a depth of 0.3 mm are formed in advance to supply and discharge the abrasive. Furthermore, a 0.3 mm deep V
A concave and convex structure having a groove and a convex portion having a width of 0.1 mm (a second concave and convex structure in FIG. 3B), a concave portion having a depth of 0.3 mm and a width of 5 mm,
Concavo-convex structures composed of convex portions having a width of 5 mm (first concave-convex structures in FIG. 3B) are arranged in a grid at equal intervals of 20 mm.

Using this polished body, a 6-inch silicon wafer on which a thermal oxide film is formed at 1 μm and a plurality of 2 mm square convex patterns having a plurality of steps of 500 nm are formed in the same manner as in Example 1. The inch silicon wafer was polished. Comparative Example 1 A non-foamed polished body made of an epoxy resin and having a groove structure on its surface was attached to a polishing platen of a CMP apparatus. To hold the abrasive on the surface of this abrasive body,
V-grooves with a width of 0.2 mm and a depth of 0.3 mm are formed at intervals of 0.5 mm, and radial grooves with a width of 2 mm and a depth of 0.3 mm are formed to supply and discharge abrasive. Have been.

Using this polished body, a 6-inch silicon wafer on which a thermal oxide film is formed at 1 μm and a plurality of 2 mm square convex patterns having a plurality of steps of 500 nm are formed in the same manner as in Example 1. The inch silicon wafer was polished. [Comparative Example 2] A foamed abrasive having a groove structure on the surface (first layer) and an elastic body having a very large elastic modulus (second layer)
A polishing body having a laminated structure composed of the above-mentioned lamination was attached to a polishing platen of a CMP apparatus. On the surface of the first layer of the polishing body,
To hold the abrasive, the convex part width is 0.2 mm at 0.5 mm intervals,
A V-groove having a depth of 0.3 mm is formed, and a radial groove having a width of 2 mm and a depth of 0.3 mm is formed to supply and discharge the abrasive.

As in Example 1, a 6-inch silicon wafer on which a thermal oxide film is formed by 1 μm and a plurality of 2 mm square convex patterns having a plurality of steps of 500 nm are formed using this polished body. The inch silicon wafer was polished. [Evaluation] For Examples 1, 2, 3 and Comparative Examples 1, 2,
Using the polished silicon wafers, uniformity and flatness were evaluated.

Regarding the uniformity, a 6-inch silicon wafer on which a thermal oxide film was formed to a thickness of 1 μm was used.
The polishing amount profile excluding the portion of mm was measured, and the uniformity was evaluated by the following equation. Uniformity (%) = (RA-RI) / (RA + RI) × 10
Here, RA is the maximum polishing amount in the measured polishing amount profile, and RI is the minimum polishing amount in the measured polishing amount profile.

As for the flatness, a plurality of 500 nm
When a 500-nm step difference is polished on a 6-inch silicon wafer on which a plurality of 2 mm square convex patterns having a step difference are formed, residual steps are measured at a plurality of locations in the silicon wafer, and the residual steps are measured. The maximum value of the measured values was determined as flatness. Table 1 below summarizes the evaluation results of the uniformity and flatness of Examples 1, 2, and 3 and Comparative Examples 1 and 2.

[0046]

[Table 1]

According to this evaluation, characteristics such as poor uniformity or flatness as in Comparative Examples 1 and 2 were not found in Examples 1, 2 and 3, and both uniformity and flatness were excellent. The characteristics are shown. In addition, when the uniformity was evaluated in Example 2 and Comparative Example 1 except for a portion 1 mm inside from the edge, it was 8% in Example 2 and 20% in Comparative Example 1.
From this, it is clear that the polishing characteristics of the outermost periphery of the silicon wafer are sufficiently improved by the polishing body according to the present invention.

[0048]

As described above, according to the present invention, it is not necessary to improve the lamination structure of the polishing body and the polishing head, and by forming two or more types of uneven structures on the surface of the polishing body, the same structure can be obtained. The polishing body can apparently coexist a hard polishing body and a soft polishing body, and improve the uniformity and flatness polishing characteristics which are generally said to be in a trade-off even when using a conventional polishing apparatus. And a polishing method using the same. Accordingly, there is an effect that the yield of the semiconductor manufacturing process can be improved without spending the cost required for the polishing step.

[Brief description of the drawings]

FIG. 1 is a view showing a polishing body according to a first embodiment of the present invention. FIG. 1A is a plan view of the polishing body, and FIG.
FIG. 2B is a cross-sectional view taken along the line AA ′ of FIG.

FIG. 2 is a view showing a polishing body according to a second embodiment of the present invention. FIG. 2A is a plan view of the polishing body, and FIG.
FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG.

FIG. 3 is a view showing a polishing body according to a third embodiment of the present invention. FIG. 3A is a plan view of the polishing body, and FIG.
FIG. 3B is a cross-sectional view taken along the line CC ′ of FIG.

FIG. 4 is a view showing a polishing body according to a fourth embodiment of the present invention. FIG. 4A is a plan view of the polishing body, and FIG.
FIG. 4B is a cross-sectional view taken along the line DD ′ of FIG.

FIG. 5 is a conceptual diagram of a planarization technique in a semiconductor manufacturing process, and is a cross-sectional view of a semiconductor device. FIG. 5 (a)
Is an example of flattening an interlayer insulating film on the surface of a semiconductor device. FIG. 5B shows an example in which a metal film on the surface of a semiconductor device is polished to form a so-called damascene.

FIG. 6 is a schematic configuration of a conventional CMP apparatus.

[Explanation of symbols]

11, 12, 13: grooves for supplying and discharging abrasives 21: silicon wafer 22: interlayer insulating film of SiO ₂ 23: metal film of Al 24: semiconductor device 131 ··· Polishing member 132 ··· Polishing object holder (polishing head) 133 ··· Polishing object (silicon wafer) 134 ··· Polishing agent supply unit 135 ··· Polishing agent 136 ··· Polishing surface plate 137 ... Abrasives

Claims (9)

[Claims] 1. A polishing apparatus for polishing an object to be polished by relatively moving the object to be polished and the object to be polished while an abrasive is interposed between the object to be polished and the object to be polished. A polishing body, wherein two or more different types of uneven structures are periodically or aperiodically formed on the surface. 2. In a region where the same type of the uneven structure is formed, two or more concave portions of the uneven structure and two or more convex portions of the uneven structure are formed. An abrasive body according to item 1. 3. The uneven structure according to claim 1, wherein the uneven structure comprises a first uneven structure and a second uneven structure.
The concave portion of the first concave-convex structure and the concave portion of the second concave-convex structure are grooves, and the width of the convex portion of the first concave-convex structure is 3. The structure according to claim 2, wherein the width is at least twice as large as the width of the projection of the uneven structure.
An abrasive body according to item 1. 4. The polishing method according to claim 1, wherein the region having a circular shape and the same type of the concavo-convex structure is formed concentrically. body. 5. The polishing body according to claim 1, wherein the regions in which the same type of uneven structure are formed are arranged in a lattice. 6. A surface according to claim 1, further comprising a groove for supplying and discharging said abrasive.
A polishing body according to any one of the above. 7. The polishing body according to claim 1, wherein the Vickers hardness k is 2.5 (Kg / mm ² ) <k <30 (Kg / mm ² ). 8. A first substrate having the uneven structure formed on a surface thereof.
And a second layer laminated on the first layer, wherein the elastic modulus of the second layer is larger than the elastic modulus of the first layer. 8. The polishing body according to any one of 1 to 7. 9. A polishing method for polishing an object to be polished by relatively moving the object to be polished and the object to be polished while an abrasive is interposed between the object to be polished and the object to be polished, wherein: An object to be polished is a silicon wafer on which a semiconductor device is formed, and a polishing method using the polished body according to claim 1.