JPH0794455A - Formation of wiring - Google Patents

Abstract

PURPOSE:To prevent the corrosion of a wiring forming device by smoothing the surface of a metallic film when the polishing of the metallic film is completed under a condition where the thickness of the film is easily controlled by polishing the metallic film with abrasive grains and a specific abrasive grain liquid. CONSTITUTION:After forming grooves 11b into an insulating film 11 and a metallic film 12 containing copper on the film 11, the entire surface of the insulating film 11 is flattened by removing the film 12 from the surface of the film 11 by polishing and the grooves 11b are filled with metallic films 12a as wiring. At the time of polishing the metallic film 12, an aqueous solution of hydrochloric acid, ammonium persulfate, chromium oxide, phosphoric acid, or ammonium hydroxide or an aqueous solution containing copper chloride ammonium and ammonium hydroxide or containing ammonium hydroxide and hydrogen peroxide, or a mixture of these solutions is used as an abrasive grain liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring forming method,
More specifically, the present invention relates to a method for forming wiring in a semiconductor device by polishing.

[0002]

2. Description of the Related Art FIG. 13 is a schematic sectional view showing a step of forming a conventional wiring. FIG. 13A shows a state in which a groove is formed in an insulating film and a metal film is formed on the upper surface of the insulating film. (B)
Is a state where the metal film is removed to the surface of the insulating film by polishing,
(C) shows a state in which polishing is further continued. The conventional wiring formation method is as follows:
g) S on the substrate (not shown) having a substantially flat shape.
An insulating film 21 such as iO ₂ is formed. Thickness t of insulating film 21
_a is the thickness t _b of the metal film 22a to be wiring and the metal film 22a
It is set to be equal to the sum of the thickness t _c of the insulating film 21a located below (t _a = t _b + t _c ). Next, using a photolithography technique, patterning processing is performed on a predetermined portion of the insulating film 21 to form a groove 21b. After this,
Metal film 2 made of Al or Al alloy or the like on insulating film 21
2 is formed (a). Next, the metal film 22 on the insulating film surface 21c is removed by polishing to planarize the entire surface, and the metal film 22a as a wiring is formed in the groove 21b of the insulating film 21.
Are formed by embedding. For this polishing, Al ₂
O ₃ particles and the like, and sulfuric acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution and the like are listed as the abrasive liquid. When these abrasive liquids are used, Al or Al may be used depending on the polishing rate of the insulating film 21.
The polishing rate of the metal film 22 made of an alloy is increased, and the thickness of the metal film 22a to be the wiring at the end of polishing is easily controlled (b) (Japanese Patent Laid-Open No. 62-102543).

[0003]

In recent years, with the miniaturization and high integration of LSIs, there is an increasing need to prevent disconnection and short circuit of the wiring, and therefore the electromigration resistance of the wiring material of the metal film 22 is small. Copper (Cu), which has a high electromigration resistance, has been attracting attention in place of Al.

In the above-mentioned wiring forming method, an aqueous solution of sulfuric acid or an aqueous solution of acetic acid is used as the abrasive liquid, and the metal film 22 containing copper is used.
And the insulating film 21 are polished, the insulating film 2 of the metal film 22
The polishing rate ratio R for 1 is small. Therefore, FIG.
As shown (c), the after polishing until the surface of the insulating film 21c has arrived, susceptible further polished metal film 22a and the insulating film 21, the thickness t _b of the metal film 22a as the wiring at the end of polishing There is a problem that it is difficult to control, and thus it is difficult to reliably form a metal film wiring containing copper having a high electromigration resistance.

Further, in the above-mentioned wiring forming method, when the nitric acid aqueous solution is used as the abrasive liquid, the insulating film 2 of the metal film 22 is used.
Although the polishing rate ratio R with respect to 1 can be large, there is a problem that it is difficult to put it into practical use because corrosion occurs in the metal member (especially stainless steel) that constitutes the polishing apparatus.

When Al ₂ O ₃ is used for the abrasive grains in the above-mentioned wiring forming method, since copper is softer than Al, the surface of the metal film 22a containing copper is easily scratched,
There is a problem that the characteristics of the wiring are adversely affected.

The present invention has been made in view of the above problems, and can easily control the film thickness of the metal film at the end of polishing, smooth the surface of the metal film, and provide wiring. It is an object of the present invention to provide a method for forming a wiring capable of preventing corrosion of a device used for forming a wiring.

[0008]

In order to achieve the above-mentioned object, a method of forming a wiring according to the present invention comprises a method of forming a metal film containing copper on an insulating film having irregularities, and then forming an abrasive grain and an abrasive grain liquid. In the method of forming a wiring to be flattened by polishing using, as the abrasive liquid, hydrochloric acid aqueous solution, ammonium persulfate aqueous solution, chromium oxide aqueous solution, phosphoric acid aqueous solution, ammonium hydroxide aqueous solution, and an aqueous solution containing ammonium copper chloride and ammonium hydroxide An aqueous solution containing ammonium hydroxide and hydrogen peroxide or a mixed solution of the aqueous solutions is used (1).

Further, in the method of forming a wiring according to the present invention, after forming a metal film containing copper on an insulating film having irregularities,
In the method for forming a wiring in which polishing is performed using abrasive grains and an abrasive solution, the average grain size of the abrasive grains is 0.1 μm.
It is characterized by using the following SiO ₂ particles (2).

[0010]

The present inventor includes an aqueous solution of hydrochloric acid, an aqueous solution of ammonium persulfate, an aqueous solution of chromium oxide, an aqueous solution of phosphoric acid, an aqueous solution of ammonium hydroxide, an aqueous solution containing ammonium copper chloride and ammonium hydroxide, and ammonium hydroxide and hydrogen peroxide. When polishing is performed using an aqueous solution or a mixed solution of the aqueous solutions as an abrasive liquid, a polishing rate R _K when polishing a metal film containing copper and a polishing rate R _Z when polishing SiO ₂ as an insulating film It was found that the ratio R _K / R _Z (hereinafter, R _K / R _{Z is referred} to as a polishing rate ratio R) is larger than 1. In the case of polishing using an abrasive grain and an abrasive liquid, the polishing surface locally becomes high temperature and high pressure, and the active surface is exposed, so that chemical reaction with the abrasive liquid and mechanical etching It acts synergistically and the polishing rate ratio R is increased. As the polishing rate ratio R becomes larger than 1 (for example, about 5 or more), the stopper action of the insulating film during polishing becomes stronger, and when the polishing reaches the surface of the insulating film, the progress of polishing is stopped. You will get it.

According to the wiring forming method (1) of the present invention, an aqueous solution of hydrochloric acid, an aqueous solution of ammonium persulfate, an aqueous solution of chromium oxide, an aqueous solution of phosphoric acid, an aqueous solution of ammonium hydroxide, copper ammonium chloride and ammonium hydroxide are used as the abrasive liquid. The polishing rate ratio R can be made larger than 1 because the aqueous solution containing the above, the aqueous solution containing the ammonium hydroxide and the hydrogen peroxide, or the mixed solution of the above aqueous solutions is used, and the stopper action of the insulating film at the time of polishing is strengthened. When the polishing reaches the surface of the insulating film, the progress of polishing is suppressed, and as a result, the metal film thickness as the wiring can be surely controlled. Further, since all of these aqueous solutions are weakly corrosive to the constituent materials of the polishing apparatus, use of these aqueous solutions facilitates practical application of the polishing apparatus.

According to the wiring forming method (2) of the present invention, SiO having an average grain size of 0.1 μm or less is used as abrasive grains.
And using ₂ particles, SiO ₂ than Al ₂ O ₃ particles
Since the particles have low hardness and are fine particles, the surface of a relatively soft metal film containing copper is not easily scratched, and polishing does not impair the wiring characteristics.

[0013]

EXAMPLES AND COMPARATIVE EXAMPLES Examples of the wiring forming method according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of a wiring forming method according to the present invention in the order of steps. FIG. 1A shows a state in which a groove is formed in an insulating film and a metal film is formed on the upper surface of the insulating film. , (B) show a state where the metal film is removed to the surface of the insulating film by polishing. To form wiring in a semiconductor device, first, LP-CVD is performed.
(Low Pressure-Chemical Vapor Deposition) method is used to deposit SiO ₂ on a substrate (not shown) having a substantially flat shape.
The insulating film 11 is formed. Next, using a photolithography technique, a patterning process is performed on a predetermined portion of the insulating film 11 to form a groove 11b. After that, the metal film 12 containing copper is formed on the insulating film 11 by the ECR sputtering method (a). Next, the metal film 12 on the insulating film surface 11c is removed by polishing to planarize the entire surface, and the groove 11b of the insulating film 11 is embedded with the metal film 12a as a wiring. During this polishing, hydrochloric acid aqueous solution, ammonium persulfate aqueous solution, chromium oxide aqueous solution, phosphoric acid aqueous solution, ammonium hydroxide aqueous solution, aqueous solution containing copper chloride ammonium and ammonium hydroxide, ammonium hydroxide and hydrogen peroxide are used as abrasive liquids. An aqueous solution containing or a mixed solution of these aqueous solutions is used (b).

In the following, SiO ₂ particles having an average particle size of about 0.1 μm are used as the abrasive grains, the composition of Al and copper in the metal film 12 is changed, and the SiO ₂ film as the insulating film 11 is formed with respect to the metal film 12. With respect to the polishing rate ratio R, the results of investigation for each of the abrasive liquids shown in Table 1 below will be described. It should be noted that as Comparative Example 1, an abrasive grain liquid was used as an aqueous sulfuric acid solution having a pH of 2.2, as Comparative Example 2 an aqueous nitric acid solution having a pH of 2.2, and as Comparative Example 3 a pH of 2.
The case of polishing with the acetic acid aqueous solution of No. 2 will be also described.

[0015]

[Table 1]

FIGS. 10 and 12 are curve diagrams showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquids of Comparative Examples 1 and 3 were used. As is clear from FIGS. 10 and 12, a sulfuric acid aqueous solution having a pH of 2.2 in Comparative Example 1 and Comparative Example 3
When the acetic acid aqueous solution of pH 2.2 is used, the polishing rate ratio R
Is about 1 and is unsuitable for forming wiring by the metal film 12 containing copper.

FIG. 11 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive grain liquid of Comparative Example 2 was used. As is clear from FIG. 11, the pH of Comparative Example 2
When the nitric acid aqueous solution of 2.2 is used, the polishing rate ratio R is about 1
It is about 0-8. However, the abrasive liquid of Comparative Example 2 corrodes the constituent materials of the polishing apparatus and is not suitable for forming wiring by polishing.

On the other hand, FIG. 2 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 1 is used. As is clear from FIG. 2, when a 3% hydrochloric acid aqueous solution is used as the abrasive liquid, the polishing rate ratio R gradually decreases from about 20 as the content of copper in the metal film 12 increases, but the content of copper does not increase. When the amount is about 40% or more, the polishing rate ratio R becomes substantially constant (R≈10).

As is clear from these results, according to the wiring forming method (1) of Example 1, the polishing rate ratio R was 2
0-10, the stopper effect of the insulating film 11 at the time of polishing can be strengthened, and when the polishing reaches the surface of the insulating film, the progress of polishing can be stopped, and as a result, as a wiring. It is possible to reliably control the thickness of the metal film 12a. Further, a 3% hydrochloric acid aqueous solution has a weak corrosiveness with respect to the constituent materials of the polishing apparatus, and is therefore practical as an abrasive liquid.

In Example 1, a 3% hydrochloric acid aqueous solution was used as the abrasive liquid, but the concentration is not limited to this.
An aqueous solution of hydrochloric acid having another concentration can also be used.

FIG. 3 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 2 is used. As is clear from FIG. 3, when an ammonium persulfate 5% aqueous solution is used as the abrasive liquid, the polishing rate ratio R gradually increases from approximately 5 as the content of copper in the metal film 12 increases, and the content of copper is increased. When the amount is about 80% or more, the polishing rate ratio R becomes constant (R≈14).

As is clear from this result, according to the wiring forming method (1) of the second embodiment, the polishing rate ratio R is 5
Since it can be set to 14 and the corrosiveness with respect to the polishing apparatus is weak, it is possible to obtain substantially the same effect as that of the first embodiment.

In Example 2, a 5% ammonium persulfate aqueous solution was used as the abrasive liquid, but the concentration is not limited to this, and an ammonium persulfate aqueous solution having another concentration can be used.

FIG. 4 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 3 is used. As is clear from FIG. 4, when a chromium oxide (6) saturated aqueous solution is used as the abrasive liquid, the polishing rate ratio R is approximately 3 as the content of copper in the metal film 12 increases.
Then, when the copper content becomes about 80% or more, the polishing rate ratio R becomes substantially constant (R≈13).

As is clear from these results, according to the wiring forming method (1) of the third embodiment, the polishing rate ratio R is 3
To 13 and the corrosiveness with respect to the polishing apparatus is weak, it is possible to obtain substantially the same effect as that of the first embodiment.

In the case of Example 3, a chromium oxide (hexavalent) saturated aqueous solution was used as the abrasive liquid, but it is not limited to the chromium oxide (hexavalent) saturated aqueous solution, and (3 valent), (4)
It is also possible to use (valent), (pentavalent) chromium oxide aqueous solutions.
Further, in the case of Example 3, a chromium oxide (hexavalent) saturated aqueous solution was used as the abrasive liquid, but the concentration is not limited to this, and a chromium oxide aqueous solution having another concentration can be used.

FIG. 5 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 4 was used. As is clear from FIG. 5, when the phosphoric acid 3% aqueous solution is used as the abrasive liquid, the polishing rate ratio R gradually increases from about 13 as the content of copper in the metal film 12 increases, and the content of copper is When the polishing rate ratio R becomes approximately 100%, the polishing rate ratio R becomes approximately 14.5.

As is clear from these results, according to the wiring forming method (1) of the fourth embodiment, the polishing rate ratio R is 1
It can be set to 3 to 14.5, and the corrosiveness to the polishing apparatus is weak, so that the same effect as in the case of Example 1 can be obtained.

In the case of Example 4, 3% phosphoric acid was added to the abrasive grain liquid.
Although an aqueous solution was used, the concentration is not limited to this, and an aqueous solution of phosphoric acid having another concentration can be used.

FIG. 6 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 5 is used. As is clear from FIG. 6, when an ammonium hydroxide 5% aqueous solution is used as the abrasive liquid, the polishing rate ratio R gradually increases from approximately 5 as the content of copper in the metal film 12 increases, and the content of copper is increased. Is about 80% or more, the polishing rate ratio R becomes substantially constant (R = 10.5).

As is clear from this result, according to the wiring forming method (1) of the fifth embodiment, the polishing rate ratio R is 5
Since it can be set to ˜10.5 and the corrosiveness against the polishing apparatus is weak, it is possible to obtain substantially the same effect as that of the first embodiment.

In Example 5, a 5% ammonium hydroxide aqueous solution was used as the abrasive liquid, but the concentration is not limited to this, and an ammonium hydroxide aqueous solution having another concentration can be used.

FIG. 7 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 6 is used. As is clear from FIG. 7, when a mixed solution of a 5% aqueous solution of copper (divalent) ammonium chloride and a 10% aqueous solution of ammonium hydroxide was used as the abrasive liquid, as the content of copper in the metal film 12 increased, The polishing rate ratio R gradually increases from about 6, and when the copper content is about 80% or more, the polishing rate ratio R becomes substantially constant (R = 12).

As is clear from these results, according to the wiring forming method (1) of the sixth embodiment, the polishing rate ratio R is 6
Since it can be set to 12 and the corrosiveness against the polishing apparatus is weak, it is possible to obtain substantially the same effect as in the case of the first embodiment.

In the case of Example 6, a 5% aqueous solution of copper (divalent) ammonium chloride was used as a part of the abrasive grain liquid, but it is not limited to a 5% aqueous solution of copper (divalent) ammonium chloride. An aqueous solution of copper chloride (monovalent) ammonium can also be used. Further, in the case of Example 6, a 5% copper chloride (divalent) ammonium aqueous solution + a 10% ammonium hydroxide aqueous solution was used as the abrasive liquid, but the concentration is not limited to this, and copper chloride of another concentration is used. An ammonium aqueous solution + ammonium hydroxide aqueous solution can also be used.

FIG. 8 is a curve diagram showing the relationship between the polishing rate ratio R and the copper content when the abrasive liquid of Example 7 was used. As is apparent from FIG. 8, when a mixed solution of an ammonium hydroxide 5% aqueous solution and a hydrogen peroxide 5% aqueous solution is used as the abrasive liquid, the polishing rate ratio R increases as the content of copper in the metal film 12 increases. Gradually increases from about 5, and when the copper content is about 80% or more, the polishing rate ratio R
Is approximately constant (R = 16).

As is clear from these results, according to the wiring forming method (1) of the seventh embodiment, the polishing rate ratio R is 5
Since it can be set to 16 and the corrosiveness with respect to the polishing apparatus is weak, it is possible to obtain substantially the same effect as that of the first embodiment.

In Example 7, an ammonium hydroxide 5% aqueous solution + hydrogen peroxide 5% aqueous solution was used as the abrasive grain liquid, but the concentration is not limited to this, and an ammonium hydroxide aqueous solution having another concentration is used. + Aqueous hydrogen peroxide solution can also be used.

In another embodiment, an aqueous solution of hydrochloric acid, an aqueous solution of ammonium persulfate, an aqueous solution of chromium oxide, an aqueous solution of phosphoric acid, an aqueous solution of ammonium hydroxide, an aqueous solution containing ammonium copper chloride and ammonium hydroxide, or ammonium hydroxide and hydrogen peroxide. It is also possible to use a solution in which an aqueous solution containing is mixed as the abrasive grain liquid.

In Examples 1 to 7 described above, SiO ₂ particles having an average particle size of about 0.1 μm were used as the abrasive grains, but in another example, the abrasive particles had an average particle size of about 0.1 μm. Approximately 0.02
SiO ₂ particles or the average particle size is substantially zero ～5.0Myuemu.
By using Al ₂ O ₃ particles of 5 μm, it is possible to obtain substantially the same effect as in the case of Example 1.

Next, as Example 8, the average particle size was about 0.1.
The results of measuring the surface roughness of the case where the copper-containing metal film 12 is polished by using the SiO ₂ particles of μm suspended in water will be described. As Comparative Example 4, Al ₂ O ₃ particles having an average particle diameter of about 0.1 μm suspended in water were used for polishing. The results are shown in Table 2 below.

[0042]

[Table 2]

As is clear from Table 2, when polishing the metal film 12 containing copper, the surface roughness of the metal film 12a as a wiring is S more than that of Al ₂ O ₃ particles as abrasive grains.
It can be seen that it is better to use iO ₂ particles.

FIG. 9 is a curve diagram showing the relationship between the surface roughness of the metal film 12a containing copper after polishing and the average particle size of SiO ₂ particles. In Example 9, the average particle size is 0.0
As SiO ₂ particles of ₂ μm, 0.05 μm, and 0.1 μm suspended in water, S having an average particle diameter of 0.5 μm, 1 μm, 1.5 μm, 2 μm, and 3 μm was used as Comparative Example 5.
A suspension of iO ₂ particles in water was used. As apparent from FIG. 9, when the average particle size as the abrasive grains used the following SiO ₂ particles 0.1 [mu] m, a surface roughness R _a of the metal film 12a containing copper is substantially 0.01 [mu] m.

As is clear from these results, in the wiring forming methods according to Examples 8 and 9, the hardness of SiO ₂ particles is lower than that of Al ₂ O ₃ particles, and copper is used because it is a fine grain. Including the relatively soft metal film surface without damaging,
It is possible to prevent the characteristics of the wiring from being damaged by polishing.

In Examples 8 and 9, SiO ₂ particles having an average particle size of 0.1 μm or less were suspended in water, but in another Example, the SiO ₂ particles were used in an aqueous hydrochloric acid solution. , An aqueous solution of ammonium persulfate, an aqueous solution of chromium oxide, an aqueous solution of phosphoric acid, an aqueous solution of ammonium hydroxide, an aqueous solution containing ammonium cupric chloride and ammonium hydroxide, an aqueous solution containing ammonium hydroxide and hydrogen peroxide, or a mixed solution of the above aqueous solutions. You may use a thing, in this case,
The same effect as that of the first embodiment can be obtained, and the same effect as that of the eighth and ninth embodiments can be obtained.

Further, in the case of the above-mentioned Examples 1 to 9, the ECR sputtering method was used for forming the metal film 12,
Others such as Cu (HFA) ₂ , Cu (DPM) ₂ , C
u (AcAc) ₂ , Cu (FOD) ₂ , Cu (PPM)
_{Even if} a CVD method using a gas such as ₂ is used, the metal film 12
Can be formed.

In addition, in the case of the above-mentioned first to ninth embodiments, although the result is the SiO ₂ film as the insulating film 11, other insulating films SiN, SiON, SiOF, SOG, BPSG.
The same result can be obtained even in the case of "etc."

[0049]

As described in detail above, in the wiring forming method (1) according to the present invention, a hydrochloric acid aqueous solution is used as the abrasive liquid.
Since an aqueous solution of ammonium persulfate, an aqueous solution of chromium oxide, an aqueous solution of phosphoric acid, an aqueous solution of ammonium hydroxide, an aqueous solution containing ammonium copper chloride and ammonium hydroxide, an aqueous solution containing ammonium hydroxide and hydrogen peroxide or a mixed solution of the above aqueous solutions is used, The polishing rate ratio R can be made larger than 1, the stopper effect of the insulating film at the time of polishing can be strengthened, and when the polishing reaches the surface of the insulating film, the progress of polishing can be suppressed. As a result, it is possible to reliably control the metal film thickness of the wiring. Also,
Since all of these aqueous solutions are weakly corrosive to the constituent materials of the polishing apparatus, use of these aqueous solutions can facilitate the practical use of the polishing apparatus.

Further, in the wiring forming method (2) according to the present invention, Si having an average grain size of 0.1 μm or less as abrasive grains is used.
O ₂ particles are used, and compared with Al ₂ O ₃ particles, SiO ₂ is used.
_{Since the two} particles have low hardness and are fine particles, the surface of the relatively soft metal film containing copper is not damaged, and the characteristics of the wiring can be prevented from being damaged by polishing.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a wiring forming method according to the present invention in the order of steps. FIG. 1A shows a groove formed in an insulating film and a metal film formed on the upper surface of the insulating film. Status,
(B) shows a state where the metal film is removed to the surface of the insulating film by polishing.

FIG. 2 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when a 3% hydrochloric acid aqueous solution of Example 1 is used as an abrasive grain liquid.

FIG. 3 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when an ammonium persulfate 5% aqueous solution of Example 2 is used as an abrasive grain liquid.

FIG. 4 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content when a chromium oxide (6) saturated aqueous solution of Example 3 is used as an abrasive liquid.

FIG. 5 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when a 3% phosphoric acid aqueous solution of Example 4 is used as an abrasive grain liquid.

FIG. 6 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when an ammonium hydroxide 5% aqueous solution of Example 5 was used as an abrasive grain liquid.

FIG. 7 shows the relationship between the polishing rate ratio R and the copper content when a mixed solution of a 5% ammonium chloride (2) aqueous solution and a 10% ammonium hydroxide aqueous solution of Example 6 was used as an abrasive grain liquid. FIG.

FIG. 8 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when a mixed solution of an ammonium hydroxide 5% aqueous solution and a hydrogen peroxide 5% aqueous solution of Example 7 was used as an abrasive grain liquid. Is.

FIG. 9 shows the surface roughness and S of a metal film containing copper after polishing.
FIG. 6 is a curve diagram showing a relationship with the average particle size of iO ₂ particles.

10 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when a sulfuric acid aqueous solution having a pH of 2.2 of Comparative Example 1 is used as an abrasive grain liquid. FIG.

11 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when a nitric acid aqueous solution having a pH of 2.2 of Comparative Example 2 is used as an abrasive grain liquid. FIG.

FIG. 12 is a curve diagram showing a relationship between a polishing rate ratio R and a copper content rate when an acetic acid aqueous solution having a pH of 2.2 of Comparative Example 3 is used as an abrasive grain liquid.

FIG. 13 is a schematic cross-sectional view showing a step of forming a conventional wiring, (a) shows a state where a groove is formed in an insulating film and a metal film is formed on the upper surface of the insulating film, (b) shows The state where the metal film is removed up to the surface of the insulating film by polishing, and (c) shows the state where polishing is further continued.

[Explanation of symbols]

 11 Insulating film 12 Metal film 12a Metal film as wiring

Claims (2)

[Claims] 1. A method of forming a wiring in which a metal film containing copper is formed on an insulating film having irregularities and then flattened by polishing with an abrasive grain and an abrasive grain solution, and an aqueous hydrochloric acid solution is used as the abrasive grain solution. , Ammonium persulfate aqueous solution, chromium oxide aqueous solution, phosphoric acid aqueous solution, ammonium hydroxide aqueous solution, aqueous solution containing ammonium copper chloride and ammonium hydroxide,
A method for forming a wiring, which comprises using an aqueous solution containing ammonium hydroxide and hydrogen peroxide or a mixed solution of the aqueous solutions. 2. A method for forming a wiring, comprising: forming a metal film containing copper on an insulating film having irregularities, and then planarizing the metal film by polishing with an abrasive grain and an abrasive grain solution; A method of forming a wiring, wherein SiO ₂ particles having a particle size of 0.1 μm or less are used.