JPH08139088A - Flattening of insulating film - Google Patents

Abstract

PURPOSE: To reduce the polishing area of an insulating film covering a pattern of a large shape by changing the form of the pattern to reduce the amount of polishing of the film, to contrive a shortening of the polishing time for the film as well as to ensure the margin of the polishing time to contrive to improve the flatness of the insulating film. CONSTITUTION: When a large-sized pattern 13 is provided on a substrate 11, grooves 14 are formed in the pattern 13 and steps, which correspond to the grooves 14, are formed in an insulating film 15 covering this pattern 13. In that state, the film 15 is polished to flatten. Moreover, a method of forming the grooves in the pattern can be applied in such a way even in a flattening method using a polishing stopper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of flattening an insulating film used for flattening an insulating film (interlayer film, for example) covering wiring in a manufacturing process of a semiconductor device.

[0002]

2. Description of the Related Art As a technique for flattening an interlayer film of an integrated circuit, there is a method of polishing an interlayer film made of silicon oxide (SiO ₂ ). As a technique for improving the flatness of the polished surface more than the above method, a first insulating film made of silicon oxide, a second insulating film made of boron phosphosilicate glass (BPSG), and a third insulating film made of silicon oxide are laminated, A method of polishing the second insulating film by using the first insulating film formed on the upper part of the step and the third insulating film formed on the bottom of the step as a polishing stopper has been proposed. This technology uses silicon oxide and BPS
By utilizing the selection ratio of the polishing rate with G, the deterioration of the global flatness due to the in-plane variation of the polishing rate is suppressed. Further, this method has an advantage that the global flatness can be secured without depending on the pattern size.

[0003]

In the polishing method of flattening using the above-mentioned polishing stopper, the polishing rate of the interlayer film on the upper surface of the pattern tends to decrease as the size of the pattern increases. Therefore, large size (for example, 30μ
When there is a pattern of about m squares, the polishing time required for flattening increases and the cost of the polishing process increases. Further, the polishing time increases, so that the polishing amount of the first insulating film on the bottom of the pattern step increases. for that reason,
When the first insulating film on the bottom of the step is completely polished, the first
Since the second insulating film, which is more easily polished than the insulating film, is polished to form the recesses, the flatness of the polished surface deteriorates. Therefore, when a large-sized pattern is present, the polishing time margin until the first insulating film is completely polished is reduced. On the other hand, when the increase in the polishing time due to the existence of a large size pattern is compensated by increasing the polishing rate, the margin of the polishing time is reduced and the in-plane variation of the polishing rate is increased with the increase of the polishing rate. As a result, the flatness of the polished surface is deteriorated.

An object of the present invention is to provide a method of planarizing an insulating film which is effective in reducing the pattern size of a wiring portion having a large pattern size and shortening the polishing time.

[0005]

The present invention is a method of planarizing an insulating film, which has been made to achieve the above object. That is, in the first method, when a pattern is first provided on the substrate, a groove is formed in the pattern. Then, an insulating film is formed on the substrate so as to fill the step due to the pattern and cover the pattern. Then, the surface of the substrate is flattened by polishing the surface of the insulating film.

A second method is a method of forming a first insulating film which serves as a polishing stopper in the above-described insulating film flattening method. First, in a first step, a pattern having grooves is provided on a substrate, and then a first insulating film that covers the pattern is formed on the substrate. Next, in a second step, a second insulating film having a polishing rate faster than that of the first insulating film is formed on the surface of the first insulating film so as to fill the step due to the first insulating film. Then the third
In the step, the second insulating film is polished until the surface of the first insulating film on the pattern is exposed.

A third method is a method of forming a first insulating film and a third insulating film which serve as polishing stoppers in the above-described insulating film flattening method. First, in a first step, a pattern having a groove is formed on a substrate, and then a first insulating film covering the pattern is formed on the substrate. Then in the second step, the first
The polishing speed is higher than that of the first insulating film in a state in which the surface of the second insulating film provided on the step bottom of the first insulating film is lower than the surface of the first insulating film provided on the pattern on the surface of the insulating film. 2 Form an insulating film. Subsequently, in a third step, the surface of the second insulating film and the surface of the first insulating film provided on the pattern and the second insulating film are formed.
A third insulating film having a polishing rate slower than that of the second insulating film is formed so that the surface of the third insulating film provided at the bottom of the step of the insulating film has almost the same height. Then, in a fourth step, the third and second insulating films are polished until the surface of the first insulating film provided on the pattern is exposed.

[0008]

In the method of flattening each insulating film described above, since a groove is formed in a pattern when the pattern is provided on the substrate, a large-sized pattern is effectively a small-sized pattern. A step corresponding to the groove formed in the pattern is formed in the insulating film. Therefore, when the insulating film is polished, the polishing force in the lateral direction is applied to the stepped portion of the insulating film and the groove reduces the polishing area of the insulating film, thereby increasing the polishing rate of the insulating film.

In addition to the effect of increasing the polishing rate, the second
In this method, after the first insulating film is formed, a second insulating film having a higher polishing rate than the first insulating film is formed on the surface of the first insulating film, and then polishing for planarization is performed. Therefore, the first insulating film formed on the pattern serves as a polishing stopper. In this way, since the polishing of the second insulating film is controlled by the first insulating film, unevenness is not locally generated.

In addition to the effect of increasing the polishing rate, the third
In the method, the third insulating film on the pattern step is first polished by the polishing force in the substrate surface direction (referred to as a horizontal direction), and the third and second insulating films on the pattern are further polished by the horizontal polishing force. To be polished. At this time, since the surface of the first insulating film formed on the pattern and the surface of the third insulating film formed on the side of the pattern are formed at substantially the same height, the first insulating film on the pattern is formed. Since the third insulating film on the side of the pattern serves as a polishing stopper to perform polishing, the surface of the substrate is uniformly polished and flattened. Further, since there is sufficient time until the second insulating film on the pattern is removed by polishing and the third insulating film on the side of the pattern is removed by polishing, the polishing time margin becomes long.

[0011]

EXAMPLE An example of the present invention will be described with reference to the planarization process diagram of FIG. In this figure, (1), (2), (4) and (5) are shown in sectional views, and (3) is shown in a schematic plan view. Due to space limitations, this plan view is not drawn to the same scale as the above sectional views.

As shown in FIG. 1A, the pattern forming film 12 is formed on the substrate 11 by sputtering, for example. The pattern forming film 12 has a thickness of, for example, 500 nm.
The aluminum-based metal film having a thickness of Although sputtering is used here, the pattern forming film 12 is formed by another film forming technique such as a CVD method or a vapor deposition method.
It is also possible to form a film. When the pattern forming film 12 including a plurality of layers (for example, an adhesion layer, a barrier metal layer, an aluminum-based metal layer, an adhesion layer, an antireflection layer, etc.) is formed, one or more of the above film forming methods are used. Using.

Then, as shown in FIG. 1B, the pattern forming film 12 is patterned by a lithography technique and etching to form a pattern 13. This pattern 13 is, for example, 120 μm × 120 μm
It has a size of the order. Further, when the pattern 13 is formed, the groove 14 is formed. The groove 14 is formed so as to reach the substrate 11, for example. Moreover, as shown in FIG. 3C, for example, the width wp of the groove 14 is 5 μm.
As described above, a plurality of patterns 13 are provided so that the width wp is 50 μm or less. In the above case, each groove 14 is formed with a width wg = 5 .mu.m and a length lg = 80 .mu.m.
The pattern 13 is arranged so that the width wp of the pattern 13 becomes 20 μm. When designing the groove 14, it is desirable to arrange the groove 14 so that the length direction of the groove 14 is aligned with the direction of current flow. The width w of the pattern 13 in the width direction of the groove 14
p and the width wp of the pattern 13 in the length direction of the groove 14 do not necessarily have to be the same width.

Then, as shown in (4) of FIG.
By the method, the insulating film 15 is formed on the substrate 11 so as to cover the pattern 13. This insulating film 15 is
For example, it is made of silicon oxide having a film thickness of 700 nm. After that, by polishing the surface side of the insulating film 15,
As shown in (5) of FIG. 1, the surface of the insulating film 15 is flattened. The polishing is performed by chemical mechanical polishing (CMP), for example.

In the method of flattening the insulating film of the first embodiment, polishing proceeds as shown in the sectional view of the polishing step in FIG. As shown in (1) of FIG. 2, at the stage when polishing is started, a polishing cloth (not shown) comes into contact with the step portion 15A (portion indicated by a broken line) of the insulating film 15 so that a direction substantially parallel to the surface of the substrate 11 is reached. Since a large polishing force acts (hereinafter referred to as the lateral direction), that portion is mainly polished. Then, as the polishing progresses, the insulating film 15 on the pattern 13 is formed into a mountain shape as shown in (2) of FIG. As the polishing is further advanced, as shown in FIG. 2C, the mountain-shaped portion of the insulating film 15 (the portion indicated by a chain double-dashed line) preferentially receives the polishing force in the lateral direction. As a result, the surface of the insulating film 15 is formed into a substantially flat surface.

In the flattening method of the first embodiment, the pattern 14 is formed by forming the groove 14 in the pattern 13.
A lot of steps are formed in the. Therefore, this pattern 1
Since a step corresponding to the step of the pattern 13 is also formed on the insulating film 15 formed so as to cover the step 3, a lateral polishing force acts on each step during polishing. At the same time, the wide flat portion is reduced and the polishing area is reduced. Therefore, the insulating film 15 is easily polished, so that the insulating film 1
The polishing time of 5 is shortened.

Next, a second embodiment of the method of flattening the insulating film will be described.
This will be described with reference to the flattening step sectional view of FIG. This method is a method in which the polishing time is shortened and the flatness of the polished surface is increased more than in the first embodiment. The same components as those described in FIG. 1 will be designated by the same reference numerals.

In the same manner as described in (1) and (2) of FIG. 1 above, after the pattern forming film 12 is formed on the substrate 11, the pattern forming film (12) is formed by lithography and etching. By patterning, a pattern 13 is formed on the substrate 11 as shown in FIG. The outer dimensions of this pattern 13 are, for example, 120 μm.
It has a size of about × 120 μm. Further, when the pattern 13 is formed, the groove 14 is formed. The groove 14 is formed in the same manner as described in (3) of FIG.

Subsequently, the first step shown in FIG. 3B is performed. In this step, the pattern 1 is formed by the CVD method.
The first insulating film 21 is formed on the substrate 11 so as to cover the substrate 3. The first insulating film 21 is deposited by, for example, a plasma CVD method using tetraethoxysilane (TEOS), and is formed of silicon oxide having a film thickness of 200 nm. As the film forming conditions at this time, for example, hydrogen having a flow rate of 1.5 sccm and oxygen having a flow rate of 6 sccm are used as the source gas, and the film forming temperature is set to 850 ° C. Then 450
Anneal for 30 minutes in a nitrogen atmosphere at ° C.

Then, the second insulating film 22 having a polishing rate faster than that of the first insulating film 21 is formed on the surface of the first insulating film 21 by the CVD method so as to fill the step of the first insulating film 21. To do. The second insulating film 22 is made of, for example, a BPSG film deposited by the low pressure CVD method. The BPSG film has a mass concentration of boron (B) of 4% and a mass concentration of phosphorus (P) of 7%, for example, and has a film thickness of 500 nm. The film forming conditions at this time are, for example, using monosilane (SiH ₄ ), phosphine (PH ₃ ), and diborane (B ₂ H ₆ ) as source gases, the film forming temperature is 410 ° C., and the pressure of the reaction atmosphere is atmospheric pressure. Set to.

After that, the third step is performed. In this step, the surface of the second insulating film 22 is polished to planarize the surface of the second insulating film 22 as shown in (3) of FIG. This polishing is performed by chemical mechanical polishing (CMP), for example, to form the first insulating film 2 on the pattern 13.
Repeat until 1 is exposed. The polishing conditions include, for example, a velor type [hardness (Asker-C)
Is, for example, about 82 to 85], and the polishing liquid is a mixture of fumed silica and pure water at a ratio of 1: 2. The polishing liquid supply rate is 30 cm ³ / min, and the polishing pressure is 130 cm ^3.
Polishing is performed by setting g / cm ² and the platen speed to 38 rpm.

As described above, on the surface of the substrate 11,
Planarizing film 2 including first insulating film 21 and second insulating film 22
3 is formed.

The polishing state of the insulating film flattening method of the second embodiment will be described with reference to the cross-sectional view of the polishing process of FIG. As shown in (1) of FIG. 4, when the polishing is started, the second
Since the polishing cloth (not shown) comes into contact with the step portion 22A (the portion shown by the broken line) of the insulating film 22, a large polishing force acts in a direction substantially parallel to the surface of the substrate 11 (hereinafter referred to as a lateral direction). Therefore, the step portion 22A is mainly polished. Then, as the polishing progresses, as shown in FIG. 4B, the second insulating film 22 on the pattern 13 is formed in a mountain shape.

As the polishing is further advanced, as shown in (3) of FIG. 4, the mountain-shaped portion (the portion indicated by the chain double-dashed line) 22B of the second insulating film 22 has a lateral polishing force. Since it is preferentially received, that part is polished. Eventually, the upper surface of the first insulating film 21 on the pattern 13 is exposed. At that time, the exposed first insulating film 21 serves as a polishing stopper,
The second insulating film 22 on the side of the pattern 13 is prevented from being excessively polished. As a result, the polished surfaces of the second insulating film 22 and the first insulating film 21 are formed in substantially the same plane, and flattened.

In the above polishing, the first layer made of silicon oxide is used.
The polishing rate of the insulating film 21 is 12 nm / min, and the BPS
The polishing rate of the second insulating film 22 made of G is 100 nm / min. Therefore, the polishing rate of the second insulating film 22 is the first
Since the polishing rate of the insulating film 21 is about 8 times, the polishing rate has a selectivity. For this reason, when the polishing of the second insulating film 22 on the pattern 13 progresses and the first insulating film 21 on the pattern 13 that is a convex portion is exposed, the polishing rate of the exposed portion becomes slow. Thus, even if the polishing rate in the polishing surface becomes uneven, the first insulating film 21
Since the second insulating film 22 is more easily polished between the second insulating film 22 and the second insulating film 22, the polishing rate is suppressed in the first exposed insulating film 21 portion.

Then, the first insulating film 21 having a slow polishing rate serves as a polishing stopper, and the second insulating film 22 is polished until the first insulating film 21 on the pattern 13 is completely exposed.
In this way, all the first insulating films 2 on the pattern 13 are
Polishing is completed when 1 is exposed. Thus, the first
The second insulating film 2 embedded in the groove 14 by the insulating film 21
Since the polishing of No. 2 is difficult to proceed, the flatness can be improved as compared with the flattening method of the first embodiment.

In the flattening method of the second embodiment, the pattern 14 is formed by forming the groove 14 in the pattern 13.
A lot of steps are formed in the. Therefore, this pattern 1
Pattern 2 is also formed on the second insulating film 22 formed to cover 3
Since a step is formed corresponding to the step of No. 3, a lateral polishing force acts on each step of the second insulating film 22. At the same time, the wide flat portion is reduced and the polishing area is reduced, so that the progress of polishing is accelerated. As a result, the polishing time is shortened.

Next, a third embodiment of the insulating film flattening method will be described with reference to the flattening step sectional view of FIG. This method
This is a method in which the polishing time is further shortened and the flatness is increased more than in the second embodiment. The same components as those described with reference to FIGS. 1 and 2 will be designated by the same reference numerals.

In the same manner as described in (1) and (2) of FIG. 1 above, after the pattern forming film 12 is formed on the substrate 11, the pattern forming film (12) is formed by lithography and etching. Patterning is performed to form a pattern 13 as shown in (1) of FIG. The outer dimensions of this pattern 13 are, for example, 120 μm × 120 μm
It has a size of the order. Further, when forming the pattern 13, the groove 14 is formed. This groove 14
The design is similar to that described in (3) of FIG.

Next, the first step shown in FIG. 5B is performed. In this step, the pattern 1 is formed by the CVD method.
The first insulating film 21 is formed on the substrate 11 so as to cover the substrate 3. The first insulating film 21 has a film thickness of 200, for example.
nm silicon oxide film. The first insulating film 21
Is formed of, for example, a silicon oxide film deposited by a plasma CVD method using tetraethoxysilane (TEOS), and is formed to a film thickness of 200 nm. Since the deposition conditions at this time are the same as those described in (1) of FIG. 1 above, description thereof will be omitted here.

Then, the second step is performed. In this step, on the surface of the first insulating film 21 by, for example, the CVD method,
The polishing rate is higher than that of the first insulating film 21 with the surface of the second insulating film 22 on the side of the pattern 13 being lower than the surface of the first insulating film 21 provided on the pattern 13. The second insulating film 22 is formed. The second insulating film 22 is formed of, for example, a boron phosphorus silicate glass (BPSG) film deposited by a low pressure CVD method. In this BPSG film, for example, the mass concentration of boron (B) is 4
%, The mass concentration of phosphorus (P) is 7%, and the film thickness thereof is 500 nm. The conditions for depositing the second film 14 are the same as those described in (2) of FIG. 1 above, and thus the description thereof is omitted here.

Further, the third step is carried out. In this step, the third insulating film 22 having a lower polishing rate than the second insulating film 22 is formed on the surface of the second insulating film 22 by, for example, the CVD method.
The insulating film 24 is formed. The third insulating film 24 is formed of, for example, a silicon oxide film having a film thickness of 50 nm deposited by a plasma CVD method using tetraethoxysilane (TEOS). Since the deposition conditions at this time are the same as those described in (1) of FIG. 1 above, description thereof will be omitted here. The third insulating film 24 is formed on the surface of the first insulating film 21 provided on the pattern 13 and the second insulating film 24.
The height of the surface of the third insulating film 24 provided at the bottom of the step of the insulating film 22 is almost the same.

Thereafter, the fourth step shown in FIG. 5C is performed. In this step, the third insulating film 24 (portion indicated by a chain double-dashed line) and the second insulating film 22 are first formed on the pattern 13 by a polishing method (for example, chemical mechanical polishing).
(A portion indicated by a chain line) is polished. And pattern 1
The second insulating film 22 is polished until the surface of the first insulating film 21 formed on the upper part of the third insulating film 21 is exposed. At this time, the third insulating film 24 formed on the lateral side of the pattern 13 and the surface of the first insulating film 21 on the pattern 13 act as a polishing stopper, so that the first, second, and third insulating films 21 are formed. , 2
A flattening film 25 made of 2, 24 is formed. Since the polishing conditions are the same as those explained in (3) of FIG. 1,
The description here is omitted.

In the flattening method of the insulating film of the third embodiment, polishing proceeds as shown in the sectional view of the polishing step in FIG.

As shown in (1) of FIG. 6, when polishing is started, the polishing force in a direction substantially parallel to the surface of the substrate 11 largely acts, so that the stepped portion 24A of the third insulating film 24 (indicated by a broken line). A polishing cloth (not shown) comes into contact with the portion shown. Therefore, the step portion 24A is mainly polished. At this stage, the third insulating film 24 on the lateral side of the pattern 13 (including the groove 14) is hardly polished.

As the polishing progresses further, as shown in FIG. 6B, the second insulating film 22 above the pattern 13 also begins to be polished, and the second insulating film 22 is polished into a so-called mountain shape. In the illustrated stage, the mountain-shaped second insulating film 22 is formed.
The third insulating film 24 remains on the top of the. The third insulating film 24 is polished and removed as the polishing progresses. At this time, the upper surface of the first insulating film 21 on the pattern 13 and the third side surface of the pattern 13 (including the groove 14).
Since the upper surface of the insulating film 24 is formed at substantially the same height, the first insulating film 21 and the third insulating film 24 serve as polishing stoppers.

When the polishing is further advanced, as shown in (3) of FIG. 6, the third insulating film (2
After the removal of 4), the second insulating film 2 that remains in a mountain shape is removed.
2 (portion indicated by a chain double-dashed line) is removed by polishing.
Then, the first insulating film 2 formed on the pattern 13 is formed.
The entire surface of 1 is exposed. At this time, the upper surface of the first insulating film 21 on the pattern 13 and the lateral side of the pattern 13 (the groove 1
Since the upper surface of the third insulating film 24 (including the upper surface of the fourth insulating film) is formed at substantially the same height as the upper surface of the third insulating film 24,
24 and 24 serve as polishing stoppers. Therefore, polishing is the first
Since it is stopped by the insulating film 21 and the third insulating film 24, the substrate 11 is flattened by the first, second, and third insulating films 21, 22, 24.

In the conventional flattening method, (3) in FIG.
At the stage of, the second insulating film 22 remained on the wide pattern. Therefore, it is necessary to further polish the second insulating film 22. In the flattening method of the third embodiment, the first insulating film 21 is exposed and flattened. Thus, the polishing of the second insulating film 22 is accelerated, so that the polishing time is significantly shortened. In the polishing, the first insulating film 21
Since the exposed portion of and the third insulating film 24, which is polished to substantially the same height as the upper surface thereof, serve as a polishing stopper, the third insulating film 24 exposed to the side of the pattern 13 (including the groove 14) is exposed. The 2 insulating film 22 is not polished in a concave shape. In this way, the substrate 11 is flattened.

The polishing can be further advanced from the state shown in FIG. 6 (3). The polishing can be performed just before the third insulating film 24 disappears. In the conventional planarization method, the third insulating film on the side of the pattern is polished while polishing the second insulating film on the wide pattern. Therefore, it takes a short time to polish the second insulating film on the wide pattern. On the other hand, in the flattening method of the third embodiment, the second insulating film 22 on the pattern 13 is removed shortly after the third insulating film 24 on the side of the pattern 13 begins to be polished, so that the remaining third insulating film 22 is removed. There is sufficient time for all of the film 24 to be polished. Therefore, the time margin for controlling the polishing becomes longer than that of the conventional polishing method.

In the flattening method of the third embodiment, since the groove 14 is formed in the pattern 13, the pattern 13 is formed.
A lot of steps are formed in the. Therefore, this pattern 1
The first, second and third insulating films 21, which are formed so as to cover 3
Since steps 22 and 24 are also formed corresponding to the steps of the pattern 13, a lateral polishing force acts on each step of the second and third insulating films 22 and 24. At the same time, the wide flat portion is reduced and the polishing area is reduced, so that the progress of polishing is accelerated. As a result, the polishing time is shortened.

Further, since the first insulating film 21 serving as a polishing stopper is formed on the patterns 13 on both sides of the groove 14,
The flatness on the pattern 13 is further improved. Further, since the third insulating film 24, which serves as a polishing stopper for the part, is formed on the part where the pattern 13 is not formed,
The third insulating film 24 prevents the second insulating film 22 on the portion where the pattern 13 is not formed from being excessively polished. Therefore, the flatness of the entire surface of the substrate 11 is further improved as compared with the flattening method of the second embodiment.

Although the first insulating film 21 is formed of the silicon oxide film in the above planarization method, it may be formed of, for example, a silicon nitride film. Alternatively, it may be formed of a silicon oxide film and a silicon nitride film. Although the second insulating film 22 is formed of a silicon oxide film (for example, a BPSG film) into which impurities are introduced, it may be formed of, for example, a polycrystalline silicon film.
Alternatively, it may be formed of a silicon oxide film doped with impurities and a polycrystalline silicon film. Further, the third insulating film 24
However, the same material as that of the first insulating film 21 may be used.

A method of performing planarization polishing after forming a groove in a pattern having a large area and forming an insulating film is described in the first method.
The present invention can be applied to both the flattening method using no polishing stopper as described in the embodiments and the flattening method using a polishing stopper as described in the second and third embodiments. As its effect, since the polishing time of the insulating film on the pattern having a large area is shortened, the polishing process is shortened,
That is, the throughput can be improved.

[0044]

As described above, according to the inventions of claims 1 to 3, since the groove is formed in the pattern when the pattern is formed on the substrate, the groove is also formed in the insulating film covering the pattern. Are formed, and many steps are formed. Therefore, when the insulating film is polished, a lateral polishing force is applied to the stepped portion of the insulating film, and the polishing area is reduced by the groove, so that the polishing of the insulating film progresses rapidly. As a result, the polishing time can be shortened.

According to the invention of claim 2, in addition to the above effects, the first insulating film formed on the pattern serves as a polishing stopper, so that the polishing of the second insulating film can be controlled by the first insulating film. . Therefore, unevenness is not locally generated, so that the flatness can be improved.

According to the third aspect of the present invention, in addition to the above effects, the surface of the first insulating film above the pattern and the surface of the third insulating film on the side of the pattern are formed at substantially the same height. Therefore, the first and third insulating films can be used as polishing stoppers to polish the second insulating film. Therefore, the substrate surface can be flattened with high accuracy. Even if all the second insulating film on the pattern is removed by polishing, there is sufficient time until the third insulating film on the side of the pattern is polished and disappears. Therefore, a sufficient polishing time margin can be secured. it can.

[Brief description of drawings]

FIG. 1 is a planarization process diagram of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the polishing process of the first embodiment.

FIG. 3 is a sectional view of a flattening step according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a polishing process according to a second embodiment.

FIG. 5 is a sectional view of a flattening step according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a polishing process according to a third embodiment.

[Explanation of symbols]

 11 substrate 13 pattern 14 groove 15 insulating film 21 first insulating film 22 second insulating film 24 third insulating film

Claims (3)

[Claims] 1. An insulating film which is formed by filling a step formed by a pattern provided on a substrate and covering the pattern to form an insulating film on the substrate, and then polishing the surface of the insulating film to planarize the insulating film. In the planarizing method, a groove is formed in the pattern when the pattern is provided, and the insulating film is planarized. 2. The method of planarizing an insulating film according to claim 1, further comprising: providing a grooved pattern on the substrate, and then forming a first insulating film covering the pattern on the substrate. A second step of forming a second insulating film having a polishing rate faster than that of the first insulating film in a state of filling the step of the first insulating film on the surface of the first insulating film; 1. A method of flattening an insulating film, which comprises a third step of polishing the second insulating film until the surface of the insulating film is exposed. 3. The method of planarizing an insulating film according to claim 1, further comprising: providing a grooved pattern on the substrate, and then forming a first insulating film covering the pattern on the substrate. A second insulating film having a higher polishing rate than the first insulating film on the surface of the first insulating film, and a step bottom portion of the first insulating film provided on the pattern upper portion than the surface of the first insulating film. The second insulating film provided on
A step of forming at least a third insulating film having a polishing rate slower than the second insulating film on the surface of the second insulating film on the surface of the first insulating film and the step of the second insulating film. A third step of forming the surface of the third insulating film provided on the bottom so as to have substantially the same height, and the third insulating film until the surface of the first insulating film provided on the pattern is exposed. And a fourth step of polishing the second insulating film, the method of planarizing an insulating film.