JPH0786215A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for a semiconductor device, which can remove enough the polishing particles remaining after polishing processing by suppressing dishing, and can flatten a film favorably and form a buried metallic wiring., etc. CONSTITUTION:This manufacture comprises a process of forming a polish- resistant film 24 consisting of a material slower in polishing speed than the material of a processed film 25, a process of forming a processed film 25 on the polish-resistant film 24, and a process of polishing the processed film 25, using a polishing agent including the polishing particles 27 with diameters less than the thickness of the polish-resistant film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device such as a VLSI, and more particularly to a polishing method in a manufacturing process of a semiconductor device.

[0002]

2. Description of the Related Art In recent years, various fine processing techniques have been developed with the high integration of LSIs. The minimum feature size of the pattern has been decreasing year by year, and it is already on the order of submicrons.

A polishing technique is one of the techniques developed in order to meet such strict requirements for miniaturization. This technique is indispensable for flattening an interlayer insulating film, forming a plug, forming a buried metal wiring, and separating a buried element in a semiconductor device manufacturing process.

FIGS. 14A to 14F show an example of embedded metal wiring formation using the polishing technique. First, as shown in FIG. 14A, the insulating film 2 is formed on the semiconductor substrate 1, and the surface of the insulating film 2 is flattened. Then, in FIG.
As shown in (B), a wiring groove or an opening 3 for a connection wiring is formed in the insulating film 2 by a normal photolithography method and an etching method. Then, in FIG.
As shown in (C), the wiring metal film 4 is formed on the insulating film 2.
To form. In this case, in order to prevent mutual diffusion or reaction between the insulating film 2 and the wiring metal film 4, a barrier metal film may be formed between them.

Then, in order to leave the wiring metal film 4 only in the groove or the opening, the wiring metal film 4 is subjected to polishing treatment using alumina particles or the like as abrasive particles. In this case, it is preferable to form a film having a large polishing rate selection ratio with respect to the wiring metal film 4 as a polishing resistant film under the wiring metal film 4. As described in Japanese Patent Application No. 5-67410 filed by the applicant of the present application, the Al film 5 is used as the wiring metal film, and the structure shown in FIG.
Al film 4 is deposited by sputtering as shown in
FIG. 14 shows a state in which annealing treatment is continuously performed in vacuum.
As shown in (D), Al may be single-crystallized in the concave portion, the Al film 5 may be separated and left on the convex portion of the insulating film 2, and then the remaining Al film may be removed by polishing. Thus, as shown in FIG. 14E, the surface of the insulating film 2 and the surface of the wiring metal film 5 are flush with each other.

However, in the actual polishing step, the metal for wiring is mechanically operated between the surface to be polished of the metal film 4 for wiring and the polishing particles or between the surface to be polished and the surface plate holding the polishing agent. The film surface may be scratched and roughened, or the abrasive particles may be embedded or left in the wiring metal film 4.

Further, as shown in FIG. 14 (F), a phenomenon called dishing occurs in which the metal film 4 for wiring embedded in a groove or an opening, particularly in a wide region, has a thin central portion. When this dishing phenomenon occurs, abrasive particles tend to remain there. For example, when a low-hardness and ductile metal such as Al or Cu is used as the material of the wiring metal film 4, those tendencies are remarkable. Occurrence of scratches or dishing on the surface of the metal film for wiring, or residual polishing particles may increase the resistance of the obtained wiring,
This will cause disconnection, leading to lower reliability and lower product yield.

[0008]

In the process of manufacturing a semiconductor device, residual polishing particles after polishing treatment poses a serious problem. That is, the remaining polishing particles cause defects in the semiconductor device. Therefore, it is necessary to completely remove the polishing particles after the polishing process.

Conventionally, removal of abrasive particles after polishing has been performed by washing with pure water, scrubbing using a sponge scrubber or brush scrubber, ultrasonic cleaning,
Alternatively, chemical cleaning using a mixed solution of sulfuric acid and hydrogen peroxide is appropriately combined. However, if the metal wiring is exposed, chemical cleaning using chemicals is not possible. Therefore, in such a case, washing with water and / or scrubbing is performed.

However, during the polishing treatment, fine abrasive particles that have entered into the sub-micron-order fine wiring and the small step in the groove can be sufficiently removed by the above-mentioned water washing and / or scrub washing. Can not. For this reason, abrasive particles inevitably remain on the metal wiring.

As described above, in order to satisfactorily realize the flattening of the film, the formation of the buried metal wiring, and the like with high performance and high reliability, scratches, dishing, and polishing that occur on the surface of the film to be processed after the polishing process are performed. It is essential to prevent particles from remaining.

The present invention has been made in view of the above points, and can suppress dishing, sufficiently remove polishing particles remaining after polishing, and can favorably flatten a film and form a buried metal wiring. It is an object to provide a method for manufacturing a semiconductor device.

[0013]

According to the present invention, there is provided a step of forming a polishing resistant film made of a material having a slower polishing rate than a material of a film to be processed on at least a convex portion of a substrate having an uneven portion. The method further comprises the step of forming the film to be processed on the film, and the step of polishing the film to be processed with an abrasive containing abrasive particles having a particle diameter not larger than the thickness of the abrasion resistant film. A method of manufacturing a semiconductor device is provided.

Here, the concavo-convex portion means a concavo-convex portion that occurs when a wiring groove or a connection wiring opening is formed on the substrate. As the abrasive particles used in the present invention, silica particles, cerium oxide particles, zirconium oxide particles, alumina particles, titanium oxide particles, silicon carbide particles, diamond particles, graphite particles and the like can be used.

Materials for the polishing resistant film used in the present invention include carbon, Si, SiO ₂ , SiN, Ti and T.
iSix, W, Nb, WSix, MoSix, or the like can be used. However, as the material of the polishing resistant film, a material whose polishing rate is slower than that of the material of the film to be processed with respect to the polishing particles used in the polishing (polishing) process is selected. Therefore, it is necessary to appropriately select the combination of the material of the polishing resistant film, the material of the film to be processed, and the abrasive particles so as to satisfy the above condition. For example, carbon is used as the material of the polishing resistant film, Al is used as the material of the film to be processed, and silica particles are used as the polishing particles.

The particle size of the abrasive particles used in the present invention is set to be equal to or less than the thickness of the abrasion resistant film. This is for the following reason. That is, at the time of polishing, since the film to be processed is more easily polished than the abrasion resistant film, the polishing particles enter the film to be processed portion due to the pressure, and the polishing proceeds excessively. This is because the amount, that is, the dishing amount increases as the particle size increases, and thus the dishing amount is suppressed to about the polishing resistant film thickness.
Further, as shown in FIG. 1A, when the wiring metal 12 is embedded in the concave portion of the insulating film 11 and the polishing resistant film 13 is provided on the convex portion of the insulating film 11, the polishing particles 14 are formed.
When the particle size of the particles is extremely small with respect to the thickness of the abrasion resistant film 13, the polishing treatment makes it difficult to polish the portion where the abrasive particles 14 and the wiring metal 12 are in contact with each other. When the film 13 is removed, the wiring metal 12 protrudes from the surface of the insulating film 11 as shown in FIG. This is very unfavorable in terms of flattening. For this reason,
It is necessary to appropriately set the particle size of the abrasive particles so that the particle size / the film thickness of the abrasion resistant film ≧ 0.3. In addition, the particle size means an average particle size, and it is particularly preferable that the particle size distribution is such that the weight of particles having a particle size not more than twice the average particle size is 80% or more of the weight of all abrasive particles.

[0017]

According to the method of manufacturing a semiconductor device of the present invention, a polishing resistant film made of a material having a slower polishing rate than that of a film to be processed is formed on at least a convex portion of a substrate having an uneven portion, and the processed film is formed thereon. It is characterized in that a film is formed and the film to be processed is polished by using an abrasive containing abrasive particles having a particle diameter equal to or less than the thickness of the abrasion resistant film.

Abrasive particles having a particle size smaller than the thickness of the abrasion-resistant film polishes the film to be processed by a thickness corresponding to the particle size of itself, but since the abrasion-resistant film exists, the abrasive particles become Pressure is less likely to be applied, and the film to be processed is not further polished.
Therefore, the film to be processed is prevented from being polished to a position below the position of the lower surface of the abrasion resistant film. For this reason,
It is possible to suppress scratches and roughness on the surface, occurrence of dishing, burial of polishing particles, etc., which are problems when polishing a film to be processed made of a material having low hardness.

Further, CMP (Chemical Mechanical Po
Abrasive particles that cannot be removed by washing after lishing) are all exposed on the surface by removing the abrasion resistant film,
It can be easily removed by subsequent washing.

[0020]

Embodiments of the present invention will be specifically described below with reference to the drawings. Example 1 First, as shown in FIG. 2, a SiO ₂ film 22 is formed on a Si substrate 21, and a width of 0.4 to 10 μm and a depth of 0.4 μ are formed by an ordinary photolithography method and etching method.
The wiring groove 23 of m was formed. Then, a carbon film 24 having a thickness of 500 Å is formed on the entire surface by DC magnetron sputtering, and then an Al film 25 is formed on the entire surface of the carbon film 24 by DC magnetron sputtering in an Ar atmosphere at a pressure of 10 ⁻⁴ Torr. It was formed in a thickness of 4000 angstroms without heating. After that, the Al film 25 is heat-treated in a vacuum (for example, at a pressure of 10 ⁻⁶ Torr) to suppress the formation of a natural oxide film on the surface of the Al film 25, thereby embedding the Al film 25 by cohesion. The temperature at this time was, for example, 600 ° C. As a result, Al is single-crystallized and A is formed in the wiring groove 23.
The I film 25 was embedded, and the Al film 25 remained in an island shape on the convex portion. A sample was prepared in this way.

Next, this sample was subjected to CMP using the apparatus shown in FIG. This device is disposed on the rotatable polishing plate 31, the polishing pad 32 attached on the polishing plate 31, the polishing plate 31, and is connected to a rotatable sample holder 33 and a polishing liquid tank. The discharge portion is composed of a polishing liquid supply pipe 34 extending to the vicinity of the polishing pad 32. The sample 30 is vacuum-chucked to the sample holder 33 so that the surface to be processed faces the polishing pad 32. Also,
The polishing liquid supply pipe 34 includes means for controlling the supply amount of the polishing liquid. The polishing pad 32 includes
A polishing pad made of foamed polyurethane whose surface was processed into a suede shape was used.

In CMP, the polishing agent has a pH of 1.
1 in a dilute aqueous solution of piperazine (C ₄ H ₁₀ N ₂ ) with a particle size of 5
1 particle based on total weight of 00 Angstrom silica
What was dispersed at a ratio of 0% by weight was used. This is because, as the polishing particles suitable for CMP for forming the metal-embedded wiring, those having a particle size of 1000 angstroms or less are preferable from the viewpoint of planarization. The polishing conditions are
Polishing pressure 50 to 300 gf / cm ² , platen rotation speed 50 to 50
The speed was 0 rpm, and the polishing agent supply rate was 300 cc / min.

The polishing rate VAl of the Al film and the polishing rate Vc of the carbon film at this time are VAl = 830 angstrom / min, respectively.
, Vc = 0 angstrom / min. Therefore, it can be seen that the carbon film functions almost perfectly as a polishing resistant film. In this case, in the convex portion 26, when the carbon film 24 is entirely exposed, polishing does not proceed any further, but Al
In the wiring groove 23 where the upper surface of the film 25 is exposed, since Al has a higher polishing rate than carbon, polishing further progresses. Since the carbon film 24 is present on the convex portion 26, the carbon film 2
4 When the polishing progresses from the upper surface to a depth of about the outer diameter of the polishing particles 27, it becomes difficult to apply pressure from the polishing pad 32 to the polishing particles, and the polishing stops. At this time,
The position of the surface of the Al film 25 embedded in the wiring groove 23 and the position of the lower surface of the carbon film 24, which is a polishing resistant film, were substantially the same.

Next, the sample after CMP was washed with pure water, scrubbed with a PVA (polyvinyl alcohol) cloth, and ultrasonically cleaned (first cleaning). A cross section of the sample at this time is shown in FIG. When the abrasive particles remaining in the sample were examined by a dust checker and a SEM (scanning electron microscope), as shown in FIG. 4 (A), no abrasive particles 27 existed on the carbon film 24 of the convex portion 26. A slight amount of polishing particles 27 was confirmed on the Al film 25 embedded in the wiring groove 23.

Then, the sample was subjected to an ashing treatment by oxygen plasma under the conditions of an oxygen partial pressure of 0.9 Torr and a plasma output of 500 W to remove the carbon film 24 formed on the convex portion 26. A cross section of the sample after the ashing treatment is shown in FIG. Figure 4
As shown in (B), the position of the exposed surface of the SiO ₂ film 22 and the position of the surface of the Al film 25 were almost the same. It is considered that this is because the carbon film 24 is easily etched when exposed to oxygen plasma, but Al is not etched because it is protected by the natural oxide film formed on the surface.

Then, the sample is washed with pure water, scrubbed with a PVA cloth, and ultrasonically cleaned (second cleaning).
Then, the polishing particles 27 remaining on the Al film 25 were removed. In this state, when the abrasive particles remaining in the sample were examined by a dust checker and an SEM, the abrasive particles 27 remaining on the Al film 25 as shown in FIG.
Was found to have been removed almost completely. This is C
It is considered that by removing the carbon film 24 on the protrusions 26 after the MP, only the abrasive particles 27 were projected from the surface of the substrate and became easy to remove by the mechanical treatment.
Further, the surface of the Al film 25 buried in the wiring groove 23 was not scratched, and dishing did not occur.

Here, the thickness of the carbon film 24, which is a polishing resistant film, is kept constant at 500 Å, and the particle size of the SiO ₂ particles, which are polishing particles, is variously changed to 200 to 750 Å. The sample shown in FIG. 2 was subjected to CMP in the same manner as described above by changing the ratio of / polishing-resistant film thickness, the carbon film 24 was removed by ashing, and the polishing particles were removed by washing. The number of abrasive particles having a particle diameter of 0.2 μm or more remaining on the surface of each sample after the second washing was measured using a dust counter. The result is shown in FIG. The width of the wiring groove of the sample was 0.4 μm.

As is apparent from FIG. 5, when the particle size of the polishing particles is smaller than the thickness of the polishing resistant film, that is, when the ratio of the polishing particle size / polishing resistant film thickness is smaller than 1, the sample surface The number of abrasive particles remaining in is extremely small. In this example, after removing the polishing-resistant film and washing, the average number of remaining polishing particles was 10 or less per 6-inch wafer.

Regarding the above phenomenon, when the particle size of the abrasive particles was smaller than the thickness of the abrasion resistant film, the particle size of the abrasive particles was confirmed in the range of 100 to 1000 angstroms. The Al film 25 in the groove 23 was polished from the upper surface of the polishing resistant film to a depth of about the particle size of the polishing particles. That is, by using the abrasive particles having a particle diameter smaller than the thickness of the abrasion resistant film, the position of the upper surface of the formed Al film 25 becomes equal to or higher than the position of the lower surface of the abrasion resistant film. It turned out. Therefore, by performing water washing, scrub washing, and ultrasonic washing in this state, the abrasive particles can be reliably removed.

In this embodiment, PV is used for scrub cleaning.
A cloth is used, but sponge is used instead of PVA cloth.
Equivalent results were obtained using a nylon brush, polyurethane foam cloth, non-woven cloth, or the like. Example 2 As shown in FIG. 6, a SiO ₂ film 22 was formed on a Si substrate 21, and a carbon film 24 having a thickness of 500 Å was formed on the entire surface by a DC magnetron sputtering method. Then, the wiring groove 23 having the same size as that of the example 1 was formed by the usual photolithography method and etching method. Then, an Al film 25 having a film thickness of 4000 angstrom was formed on the entire surface by DC magnetron sputtering in an Ar atmosphere at a pressure of 10 ⁻⁴ Torr. At this time, by raising the temperature of the Si substrate 21 to, for example, 500 ° C., the Al film exhibited a flow shape as shown in FIG. A sample was prepared in this way.

CMP was performed on this sample in the same manner as in Example 1 to fill the Al film 25 in the wiring groove 23 and to form the protrusion 2
The excess Al film on 6 was removed. After that, when the sample was subjected to the first cleaning, the ashing treatment, and the second cleaning in the same manner as in Example 1, almost all the abrasive particles remaining on the surface of the sample could be removed.

Next, the dependency of the dishing amount of the sample on the polishing time was examined. What is dishing amount?
As shown in, the distance D from the upper surface position of the carbon film 24 to the position of the thinnest part of the Al film 25. In addition,
As the particle size of the polishing particles 27 used, 500 angstroms and 1000 angstroms were selected, the thickness of the carbon film 24 as a polishing resistant film was 500 angstroms, and the width of the Al film 25 serving as the wiring width was 10 μm. .

As shown in FIG. 8, the relationship between the dishing amount and the polishing time is such that when the particle size of the polishing particles is the same as the polishing resistant film thickness (500 angstroms), the dishing amount is suppressed below the film thickness. . Further, the polishing is continued until the excess Al film 25 is completely removed,
Even when the time was doubled, the dishing amount was less than the film thickness. Further, as the particle size of the abrasive particles increases, the polishing rate also increases, but the dishing amount also tends to increase. further,
The increase (gradient) in the dishing amount after the surplus Al film 25 is removed is also larger than that in the case where the grain size is 500 Å. When the dishing amount was examined by changing the width of the Al film 25, it was almost the same in the width of 0.5 to 10 μm.

Next, FIG. 9 shows the dishing amount of the Al film having a width of 10 μm when the thickness of the polishing resistant film is kept constant at 500 Å and the particle size of the polishing particles is changed.
As shown in FIG. 9, there is an inflection point in the graph when the particle size of the abrasive particles is the same as the abrasion resistant film thickness (500 Å). When the grain size is less than the inflection point, the dishing amount is less than the polishing resistant film thickness and changes gently. As described above, from FIGS. 8 and 9 described above, it was found that a significant improvement effect on the dishing amount can be expected by polishing with the polishing particles having a particle diameter equal to or less than the polishing resistant film thickness. Example 3 As shown in FIG. 10, a SiO ₂ film 22 is formed on a Si substrate 21.
Then, a wiring groove 23 having a width of 0.4 to 10 μm and a depth of 0.4 μm was formed by the usual photolithography method and etching method. Then, a polycrystalline silicon film 28 having a thickness of 500 angstrom was formed on the entire surface by the AC magnetron sputtering method. Then, a Cu film 29 having a film thickness of 4000 angstrom was formed on the entire surface by a DC magnetron sputtering method in an Ar atmosphere at a pressure of 10 ⁻⁴ Torr. At this time, by raising the temperature of the Si substrate 21 to, for example, 700 ° C., the Cu film 29 has a flow shape as shown in FIG. A sample was prepared in this way.

Then, the sample was subjected to CMP in the same manner as in Example 1 to bury the Cu film 29 in the wiring groove 23 and remove the excess Cu film on the convex portion 26. However, as the polishing agent, one prepared by mixing silica particles in an aqueous piperazine solution and mixing an oxidizing agent was used.

Next, the sample after CMP was washed with pure water, scrubbed with a PVA cloth, and ultrasonically cleaned. When the abrasive particles remaining in the sample were examined with a dust checker and a SEM, as shown in FIG. 11A, the abrasive particles 27 were not present at all on the polycrystalline silicon film 28 of the convex portion 26, and C embedded in groove 23
A small amount of abrasive particles 27 was confirmed on the u film 29.

Then, the sample was subjected to a plasma etching process using CF ₄ plasma to remove the polycrystalline silicon film 28 formed on the convex portion 26. A cross section of the sample after the plasma etching treatment is shown in FIG. Figure 11
As shown in (B), the position of the exposed surface of the SiO ₂ film 22 and the position of the surface of the Cu film 29 were almost the same.

Then, the sample is washed with pure water, scrubbed with a PVA cloth, and ultrasonically washed to obtain the Cu film 2.
The abrasive particles 27 remaining on No. 9 were removed. In this state,
Abrasive particles remaining on the sample are removed by dust checker and SE.
When examined by M, as shown in FIG.
It was found that the polishing particles 27 remaining on the u film 29 were almost completely removed. Further, the surface of the Cu film 29 embedded in the wiring groove 23 is not scratched,
There was no dishing.

In Examples 1 to 3 described above,
The case of using a slurry prepared by dispersing silica particles in an aqueous solution of piperazine having a pH of 11 as an abrasive has been described, but amines such as triethylamine, choline and TMAH (tetramethylammonium hydroxide) are used as an alkaline solution for pH adjustment. Alternatively, ammonia, alkali hydroxide or the like may be used. Example 4 As shown in FIG. 12, a SiO ₂ film 22 is formed on a Si substrate 21.
Was formed, and an Al film 25 having a thickness of 4000 angstroms and a carbon film 24 having a thickness of 500 angstroms were sequentially formed thereon by a DC magnetron sputtering method. Then, a pattern having a line width of 0.4 to 10 μm was formed by the usual photolithography method and etching method. Next, plasma C using organosilane gas
A SiO ₂ film 30 having a thickness of 10,000 Å was formed on the entire surface by the VD method. A sample was prepared in this way.

Then, the sample was subjected to CMP in the same manner as in Example 1 to remove the SiO ₂ film 30 up to the position of the upper surface of the Al film 25. However, the abrasive has a particle size of 500
A slurry having a pH of 10.0 obtained by dispersing angstrom silica particles in a potassium hydroxide solution was used.

At this time, the polishing rate Vox of the SiO ₂ film,
The polishing rate Vc of the carbon film is Vox = 1000 Å / min and Vc = 10 Å / mi, respectively.
n, and a sufficient polishing selectivity was obtained.

Next, the sample after CMP was washed with pure water, scrubbed with a PVA cloth, and ultrasonically washed. When the abrasive particles remaining in the sample were examined by a dust checker and an SEM, a small amount of abrasive particles 27 were confirmed on the SiO ₂ film 30 as shown in FIG. 13 (A).

Then, the sample was ashed in the same manner as in Example 1 to remove the carbon film 24 formed on the Al film 25. A cross section of the sample after the ashing treatment is shown in FIG. As shown in FIG. 13B, the exposed SiO ₂ film 2
The position of the second surface and the position of the surface of the Al film 25 were almost the same.

Then, the sample is washed with pure water, scrubbed with a PVA cloth, and ultrasonically washed to obtain SiO ₂
The abrasive particles 27 remaining on the film 30 were removed. In this state, when the abrasive particles remaining in the sample were examined by a dust checker and an SEM, the abrasive particles 27 remaining on the SiO ₂ film 30 were almost completely removed as shown in FIG. 13 (C). I found out that It was also found that the amount of dishing was suppressed within the polishing resistant film thickness. As described above, it was confirmed that similar effects can be obtained even when the film to be processed is other than the metal film.

[0045]

As described above, according to the method of manufacturing a semiconductor device of the present invention, at least the convex portion of the substrate having the concave and convex portion is
An abrasive containing an abrasive particle having a particle size equal to or less than the thickness of the abrasion resistant film, which is formed by forming an abrasion resistant film made of a material having a polishing rate slower than that of the material of the abrasion resistant film. Since the film to be processed is polished by using, the dishing can be suppressed, the polishing particles remaining after polishing can be sufficiently removed, and the film can be satisfactorily flattened and embedded metal wiring can be formed. Further, it becomes easy to remove the polishing particles remaining on the surface of the film to be processed after polishing.

The amount of polishing can be controlled by appropriately setting the combination of the polishing resistant film and the film to be processed or the combination of the polishing resistant film thickness and the particle size of the polishing particles.
It becomes possible to manufacture a highly reliable semiconductor device.

[Brief description of drawings]

1A and 1B are cross-sectional views for explaining a lower limit of a ratio of a particle diameter of abrasive particles / a film thickness of an abrasion resistant film.

FIG. 2 is a sectional view showing a sample used in Example 1.

FIG. 3 is a schematic view showing an apparatus used for a polishing process.

4 (A) to (C) are cross-sectional views for explaining a process of processing according to the method of the present invention in Example 1. FIG.

FIG. 5 is a graph showing the relationship between the ratio of particle size of abrasive particles / abrasive-resistant film thickness and the number of remaining abrasive particles.

FIG. 6 is a cross-sectional view showing a sample used in Example 2.

FIG. 7 is a cross-sectional view for explaining a dishing amount.

FIG. 8 is a graph showing the relationship between the dishing amount and the polishing time.

FIG. 9 is a graph showing the relationship between the dishing amount and the particle size of abrasive particles.

FIG. 10 is a cross-sectional view showing a sample used in Example 3.

11 (A) to (C) are cross-sectional views for explaining a process of processing according to the method of the present invention in Example 3. FIG.

FIG. 12 is a cross-sectional view for explaining the fourth embodiment.

13 (A) to 13 (C) are cross-sectional views for explaining steps of processing according to the method of the present invention in Example 4. FIG.

14A to 14F are cross-sectional views for explaining a conventional polishing method.

[Explanation of symbols]

11 ... Insulating film, 12 ... Wiring metal, 13 ... Polishing resistant film,
14, 27 ... Abrasive particles, 21 ... Si substrate, 22, 30 ...
SiO ₂ film, 23 ... Wiring groove, 24 ... Carbon film, 25 ... A
l film, 26 ... convex portion, 28 ... polycrystalline silicon film, 29 ... C
u film, 31 ... Polishing plate, 32 ... Polishing pad, 33 ... Sample holder, 34 ... Polishing liquid supply pipe.

Claims (1)

[Claims] 1. At least a convex portion of a substrate having a concave and convex portion,
A step of forming a polishing resistant film made of a material having a polishing rate slower than that of a material of the film to be processed, a step of forming the film to be processed on the polishing resistant film, and particles having a thickness not more than the thickness of the polishing resistant film A step of polishing the film to be processed using an abrasive containing abrasive particles having a diameter.