JPH09171982A - Abrasive cloth and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an abrasive cloth by which an interlayer insulating layer on an interconnection layer is polished to be flat irrespective of whether an interconnection formed in the interconnection layer As coarse or dense by a method wherein the abrasive cloth which is pasted on a surface plate and which is used to polish, a substrate contains an organic filler. SOLUTION: The constitutent resin of an abrasive cloth 3 is prepared in such a way that polyurethane prepared by adding 4,4-methylene diophenyl dilsocyanate and ethylene glycol as a chain-length extender to a polyol which is prepared by using ethylene glycol as a diol component and by using adipic acid as a dicarbolylic acid is added to a triisocyanate which its reacted with glycerin, hexamethylene diisocyanate or the like and which comprises three or more functional groups. An inorganic filler such as calcium carbonate or the like is added to, and kneaded width, the constitutent resin of the abrasive cloth 3, it is dispersed uniformly into the constituent resin of the abrasive cloth 3, and it is cross-linked and reacted by a heat treatment. Thereby, although the surface hardness of the abrasive cloth is identical to that of the constitutent resin, the compressive elasticity modulus of the abrasive cloth 3 can be made large as a whole, and an interlayer insulating layer 2c can be polished to be flat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing cloth and a method for manufacturing the same, and more particularly to a polishing cloth for improving the flatness of a substrate by chemical mechanical polishing and a method for manufacturing the same.

[0002]

2. Description of the Related Art Wiring technology for semiconductor devices such as ICs and LSIs is progressing toward miniaturization and multilayering. But,
High integration may cause a decrease in reliability.
This is because the step of the interlayer insulating layer becomes large and steep due to the progress of miniaturization and multilayering of wiring, and the processing accuracy and reliability of the wiring formed on the interlayer insulating film are deteriorated.
For this reason, it is necessary to improve the flatness of the interlayer insulating layer at present when the step coverage of Al (aluminum) wiring or the like cannot be greatly improved. Various types of interlayer insulating layer forming techniques and flattening techniques have been developed so far. However, when applied to a finely-divided wiring layer, lack of flatness of the interlayer insulating layer when the wiring interval is sparse It has become an important issue.

In recent years, a chemical mechanical polishing technique using fine particles of silicon oxide in a basic solution has been reported as a technique for flattening an interlayer insulating layer. An example of this chemical mechanical polishing method will be described with reference to the schematic side view of the substrate polishing apparatus 1 of FIG. The substrate 2 is held by a substrate holder 5 by vacuum suction or the like, and the polishing cloth 3 is attached to a surface plate 4. The substrate holder 5 and the surface plate 4 both rotate in the direction indicated by the arrow in the figure, and the slurry 6 is dropped from the slurry introducing pipe 7 near the center of rotation of the surface plate 4 and held by the substrate holder 4. The substrate 2 is brought into pressure contact with the polishing cloth 3 for polishing. Generally, a slurry usually has a particle size of 10 nm.
A metal oxide such as silicon oxide fine particles is uniformly dispersed in an aqueous potassium hydroxide solution.

An example of the planarization process of the interlayer insulating layer to which the chemical mechanical polishing is applied is shown in the substrate 2 of FIGS.
Will be described with reference to the schematic side sectional view. As shown in FIG. 3A, an insulating layer 2a such as a silicon oxide film is formed on a substrate 2, and a wiring layer 2b such as Al (aluminum) is further formed thereon by photolithography and ion etching.
To form Next, as shown in FIG. 3B, the interlayer insulating layer 2c is formed on the wiring layer 2b. After forming the interlayer insulating layer 2c, the interlayer insulating layer 2 is formed by the substrate polishing apparatus 1 shown in FIG.
By removing the convex portion of c, as shown in FIG.
flatten c. Furthermore, if necessary, the insulating layer 2a, the wiring layer 2b, and the interlayer insulating layer 2c are formed on the interlayer insulating layer 2c.
Is repeated to form a multilayer wiring board. This content is, for example, Monthly Semiconductor Wo
rld January 1994 and JP-A-6-010146.
No., published in Japanese Unexamined Patent Publication No.

An attempt to flatten the wiring layer 2b in order to realize a good multilayer wiring board has also been reported. For example, there is the IBM Damascen process. After planarizing the interlayer insulating layer 2c by polishing, a via contact for connecting upper and lower wirings and a groove for forming an upper wiring layer are formed by etching, and a metal layer is formed thereon. Then, the metal layer other than the via contact and the groove is removed by polishing to form a buried metal wiring.
The contents are S. Roeht et al PROC. I
EEE Conf. , 22 (1992).

When chemical mechanical polishing is applied to the step of flattening the insulating layer 2c, polishing is performed on the portion where the wiring layers 2b are densely arranged, as shown in the schematic side sectional view of the substrate 2 of FIG. 5 (a). The cloth 3 is not likely to be locally deformed, and the interlayer insulating layer 2c
Since only the convex region 2c2 is polished, it can be flattened. However, when chemical mechanical polishing is performed on a portion where the wiring layer 2b is sparsely arranged, the conventional polishing cloth is locally deformed and the polishing pressures in the concave region 2c1 and the convex region 2c2 are evenly pressed to each other to cause interlayer insulation. Since the layer 2c was polished, it was difficult to flatten the interlayer insulating layer 2c as shown in FIG. If the interlayer insulating layer 2c is not formed flat, in the step of forming the insulating layer 2a on the interlayer insulating layer 2c, and further forming the wiring layer 2b thereon by photolithography and ion etching, the DOF (Depth
It is difficult to form fine wiring on the stepped interlayer insulating layer 2c due to the problem of "of focus".

In addition to the above-mentioned case, an attempt has been made to review the constituent materials of the polishing cloth and increase the hardness of the polishing cloth to reduce the deformation during polishing. Jeong, Proc. MPC Con
f. (1994) and described in detail. However, with a polishing cloth that simply has a high hardness, there is a high possibility that scratches called scratches will occur on the substrate 2 during chemical mechanical polishing.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to improve the reliability of an interlayer insulating layer formed on a wiring layer by chemical-mechanical polishing flatly regardless of the density of wiring formed on the wiring layer. It is an object of the present invention to provide a polishing cloth and a method for manufacturing the same, which makes it possible to provide a large-sized multilayer wiring board.

[0009]

In order to solve the above problems, in the polishing cloth of the inventions of claims 1 and 2, the polishing cloth is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt or a metal halogen. Compound, a metal perchlorate, a metal silicate, a metal borate, a metal phosphate, and a metal arsenite, and at least one inorganic filler is contained.

In the polishing cloth of the invention of claim 3, the polishing cloth is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt, a metal halide, a metal perchlorate, a metal silicate or a metal borate. In addition to containing at least one inorganic filler selected from the group consisting of metal phosphates and metal arsenites, the surface of the inorganic filler is coated with an organic silicon compound.

The polishing cloth of the present invention is characterized in that the polishing cloth contains at least one organic filler selected from the group consisting of polyimide, polystyrene and benzoguanamine.

In the polishing cloth manufacturing method of the present invention, the constituent resin of the polishing cloth is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt, a metal halide, a metal perchlorate, The method is characterized by including a step of adding at least one inorganic filler selected from metal silicates, metal borates, metal phosphates, and metal arsenites, and a step of forming into a polishing cloth shape.

In the method for manufacturing a polishing cloth according to the present invention, the constituent resin of the polishing cloth is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt, a metal halide, a metal perchlorate or a metal silica. Acid salt, metal borate, metal phosphate,
It is characterized by comprising a step of adding at least one inorganic filler of metal arsenite, a step of coating the surface of the inorganic filler with an organic silicon compound, and a step of forming into a polishing cloth shape. .

In the method for manufacturing a polishing cloth according to the present invention, the step of adding at least one organic filler selected from the group consisting of polyimide, polystyrene and benzoguanamine to the constituent resin of the polishing cloth, and the shape of the polishing cloth. And a molding step.

The operation of the above means will be described below. If an inorganic filler such as metal carbonate or an organic filler such as polyimide is added to the constituent resin of the polishing cloth to obtain a polishing cloth containing an inorganic filler or an organic filler, the surface hardness of the polishing cloth is It is possible to obtain a polishing cloth which is the same as the constituent resin but has a large compression elastic modulus of the entire polishing cloth. Further, when the organic silicon compound is added to the constituent resin of the polishing cloth together with the above-mentioned inorganic filler, the surface of the inorganic filler is coated with the organic silicon compound to improve the affinity with the constituent resin of the polishing cloth, and Although the surface hardness is the same as that of the constituent resin of the polishing cloth, it is possible to obtain a polishing cloth having a compression elastic modulus larger than that of the constituent resin of the polishing cloth in which only the inorganic filler is added.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIGS. Note that components having the same structure as that of the conventional technology in the drawings are denoted by the same reference numerals.

Embodiment 1 This embodiment shows an example of a polishing cloth 3 in which the constituent resin of the polishing cloth 3 contains an inorganic filler such as a metal carbonate. The constituent resin of the polishing cloth 3 is glycerol, which is a polyurethane prepared by adding 4,4-methylenediphenyl diisocyanate, a polyol formed by using ethylene glycol as a diol component and adipic acid as a dicarboxylic acid, and ethylene glycol as a chain extender. It is prepared by adding tri- or more-functional triisocyanate obtained by reacting with hexamethylene diisocyanate. Then, an inorganic filler such as calcium carbonate is added and kneaded to the constituent resin of the polishing cloth 3 thus prepared, and the inorganic filler is uniformly dispersed in the constituent resin of the polishing cloth 3. Then, after being shaped into a polishing cloth, a cross-linking reaction is carried out by heat treatment, whereby a polishing cloth having the same surface hardness as the constituent resin of the polishing cloth 3 but a large overall compression elastic modulus can be obtained.

In this embodiment, the inorganic filler has an average particle size of 1 μm or an average filler length of 1 μm.
20 m of calcium carbonate to the constituent resin of the polishing cloth 3
In the case of the polishing cloth 3 with vol% added, the elastic modulus could be improved by 5 times as compared with the polishing cloth with no addition.

In the present embodiment, calcium carbonate is used as the inorganic filler, but the inorganic filler is not limited to this. Metal carbonates other than calcium carbonate, metal sulfates,
Metal nitrate, metal ammonium salt, metal halide,
It may be a metal perchlorate, metal silicate, metal borate, metal phosphate or metal arsenite. Further, the inorganic filler added to the constituent resin of the polishing pad 3 was effective when the particle size or the filler length was 0.001 μm to 10 μm, and particularly when 0.01 μm to 5 μm, good results were obtained. Further, with respect to the amount of the inorganic filler added to the constituent resin of the polishing pad 3, the effect was recognized at 0.1 vol% to 10 vol%, and particularly at 1 vol% to 5 vol%, good results were obtained.

If the polishing cloth 3 is constructed as in the case described above, the surface hardness of the polishing cloth 3 is the same as that of the constituent resin of the polishing cloth 3, but the compression elastic modulus of the entire polishing cloth 3 can be increased. . Therefore, if the above-mentioned polishing cloth 3 is attached to the surface plate 4 in the substrate polishing apparatus 1 shown in FIG. 3 and the substrate 2 is pressed against the polishing cloth 3 to perform chemical mechanical polishing, FIG. Board 2
As shown in the schematic side sectional view of FIG. 3, the polishing cloth 3 is not likely to be locally deformed not only in the dense wiring portion of the wiring layer 2b formed on the substrate 2 but also in the sparse wiring portion. Therefore, the interlayer insulating layer 2c is formed on the insulating layer 2c shown in FIG.
It can be polished flat as shown in FIG. Further, since the surface hardness of the polishing cloth 3 is the same as the constituent resin of the polishing cloth 3,
It is possible to provide a high-quality multilayer wiring board having high reliability without causing scratches on the board 2.

This embodiment can also be applied to a laminated polishing cloth in which a plurality of polishing cloths are laminated. FIG. 2 shows an example of the laminated polishing cloth 8 in which the filler-containing polishing cloth 3a of the laminated polishing cloth 8 is used as a polishing surface, and the unfilled polishing cloth 3b is attached below the polishing surface. The laminated polishing cloth 8 configured in this manner has an appropriate compression elastic modulus due to the unfilled polishing cloth 3b having a compression elastic modulus smaller than that of the filler-containing polishing cloth 3a, and there is no fear of local deformation. It can be a laminated polishing cloth 8. Therefore, as shown in the schematic side sectional view of the substrate 2 of FIG. 1A, the wiring layer 2b formed on the substrate 2 is formed.
Since there is no risk of local deformation not only in the dense wiring portion but also in the sparse wiring portion, the interlayer insulating layer 2c is flattened as shown in FIG. 1B regardless of the wiring density. Not only can it be polished, but also the entire surface of the substrate 2 can be planarized.

Embodiment 2 This embodiment shows an example of a polishing cloth 3 having a compression elastic modulus larger than that of the polishing cloth of the case shown in Embodiment 1. The constituent resin of the polishing cloth 3 is 1,4-butanediol as a diol component and 4,4-methylenediphenyldiisocyanate as a polyol prepared by using terephthalic acid as a dicarboxylic acid and 1,4-as a chain extender.
Add butanediol to make a polyurethane. Then, an inorganic filler such as silicon oxide is added to the constituent resin of the polishing cloth 3 thus prepared, and an organic silicon compound such as aminopropyltriethoxysilane is added to the constituent resin of the polishing cloth 3. These mixtures are added and kneaded to uniformly disperse the inorganic filler in the constituent resin of the polishing cloth 3. Then, after being molded into a polishing cloth and then subjected to a cross-linking reaction by heat treatment, the surface hardness is higher than that of the case shown in the first embodiment, even though it is the constituent resin of the polishing cloth 3. A polishing cloth can be obtained.

In the present embodiment, the inorganic filler is silicon oxide having an average particle size of 0.05 μm, 40 vol% is added to the constituent resin of the polishing cloth 3, and aminopropyltriethoxysilane is oxidized as the organic silicon compound. In the case of the polishing cloth 3 added so as to be 5 wt% with respect to silicon, the compressive elastic modulus could be improved 10 times as compared with the case where it was not added.

In this embodiment, the case of using silicon oxide as the inorganic filler is shown, but the present invention is not limited to this.
Metal silicates other than silicon oxide, metal carbonates, metal sulfates,
Metal nitrate, metal ammonium salt, metal halide,
It may be a metal perchlorate, a metal borate, a metal phosphate or a metal arsenite. The inorganic filler added to the constituent resin of the polishing cloth 3 has a particle size or filler length of 0.00
The effect is recognized at 1 μm to 10 μm, especially 0.01 μm
Good results were obtained at .about.5 .mu.m. Furthermore, the addition amount of the inorganic filler to the constituent resin of the polishing cloth 3 is 0.1 v.
ol% to 10vol% is effective, especially 1vol
Good results were obtained in the range of 5% to 5%.

If the polishing cloth 3 is constructed as in the above-mentioned case, the surface hardness of the polishing cloth 3 is the same as that of the constituent resin of the polishing cloth 3, but the compressive elastic modulus of the entire polishing cloth 3 is determined in the first embodiment.
Can be larger than in the case shown in. Therefore, if the above-mentioned polishing cloth 3 is adhered to the surface plate 4 in the substrate polishing apparatus 1 shown in FIG. 3 and the substrate 2 is pressed against the polishing cloth 3 for chemical mechanical polishing, As shown in the schematic side sectional view of the substrate 2, the polishing cloth 3 is the wiring layer 2 formed on the substrate 2.
Since there is no possibility of local deformation not only in the dense wiring portion but also in the dense wiring portion of b, the interlayer insulating layer 2c is flattened as shown in FIG. Can be polished to. Further, since the surface hardness of the polishing cloth 3 is the same as that of the constituent resin of the polishing cloth 3, there is no possibility of causing scratches on the substrate 2, and a highly reliable multilayer wiring board can be provided.

The present embodiment can also be applied to the laminated polishing cloth 8, but the description is omitted because it is similar to the case shown in the first embodiment.

Embodiment 3 This embodiment shows an example of the polishing cloth 3 in which the constituent resin of the polishing cloth 3 contains an organic filler such as polyimide. The constituent resin of the polishing cloth 3 is glycerol, which is a polyurethane prepared by adding 4,4-methylenediphenyl diisocyanate, a polyol formed by using ethylene glycol as a diol component and adipic acid as a dicarboxylic acid, and ethylene glycol as a chain extender. It is prepared by adding tri- or more-functional triisocyanate obtained by reacting with hexamethylene diisocyanate. Then, an organic filler such as polyimide is added and kneaded to the constituent resin of the polishing cloth 3 thus prepared, and the organic filler is uniformly dispersed in the constituent resin of the polishing cloth 3. Then, after being formed into a polishing cloth, a cross-linking reaction is performed by heat treatment, so that a polishing cloth having a surface hardness that is the constituent resin of the polishing cloth 3 but a high overall compression elastic modulus can be obtained.

In the present embodiment, the polishing pad 3 in which the organic filler is polyimide fine particles having an average particle size of 0.1 μm and 20 vol% is added to the constituent resin of the polishing pad 3 is compared with the one without addition. It was possible to improve the elastic modulus five times. In addition, although an example of polyimide is shown as the organic filler, the organic filler is not limited to this, and polystyrene or benzoguanamine may be used.

If the polishing cloth 3 contains an organic filler such as polyimide in the constituent resin of the polishing cloth 3, the polishing cloth 3
Has the same surface hardness as the constituent resin of the polishing cloth 3,
The compression elastic modulus of the polishing cloth 3 as a whole can be increased. Therefore, the above-mentioned polishing cloth 3 is added to the substrate polishing apparatus 1 shown in FIG.
Is adhered to the surface plate 4, and the substrate 2 is pressed against the polishing cloth 3 for chemical mechanical polishing. As shown in the schematic side sectional view of the substrate 2 in FIG. Formed wiring layer 2
Since there is no possibility of local deformation not only in the dense wiring portion but also in the sparse wiring portion of b, the interlayer insulating layer 2c is polished as shown in FIG. Can be performed, and the interlayer insulating layer 2c can be planarized.
Further, since the surface hardness of the polishing cloth 3 is the same as that of the constituent resin of the polishing cloth 3, there is no possibility of causing scratches on the substrate 2.

Although the present embodiment can be applied to the laminated polishing cloth 8, the description is omitted because it is similar to the case shown in the first embodiment.

[0031]

As described above in detail, in the polishing cloth and the method for manufacturing the same according to the present invention, when the polishing cloth is manufactured by adding the inorganic or organic filler to the constituent resin of the polishing cloth, the surface hardness of the polishing cloth is increased. It is possible to obtain a polishing cloth which has the same compressive elastic modulus as the entire polishing cloth while being the same as the constituent resin.
When the present invention is applied to a laminated polishing cloth in which a plurality of polishing cloths are laminated, the compression elastic modulus of the unfilled polishing cloth is smaller than that of the filler-containing polishing cloth, and the polishing surface has an appropriate compression elastic modulus. The laminated polishing cloth 8 which is not likely to be locally deformed by the filled polishing cloth having a large compressive elastic modulus
It can be. When chemical mechanical polishing is performed by pressing a substrate against a polishing cloth with a substrate polishing apparatus having such a polishing cloth, the wiring layer of the wiring layer formed on the substrate is not only dense but also sparse. Since there is no possibility of local deformation even in parts, the interlayer insulating layer can be polished flat regardless of the density of the wiring, and the entire surface of the substrate can be planarized, causing scratches on the substrate. It is possible to provide a high-quality multilayer wiring board that is highly reliable without being processed.

[Brief description of the drawings]

FIG. 1 shows the present invention, (a) is a schematic side view showing a state in which a substrate is pressed against a polishing cloth to be polished, and (b) is a schematic side sectional view of the substrate after polishing.

FIG. 2 is a schematic side view of a laminated polishing cloth showing the present invention.

FIG. 3 is a schematic side view of a substrate polishing apparatus.

4A to 4C are schematic side cross-sectional views of a substrate illustrating a step of planarizing an interlayer insulating layer.

FIG. 5 shows a conventional example, (a) is a schematic side view showing a state in which a substrate is pressed against a polishing cloth to be polished, and (b) is a schematic side sectional view of the substrate after polishing.

[Explanation of symbols]

 1 substrate polishing apparatus 2 substrate 2a insulating layer 2b wiring layer 2c interlayer insulating layer 2c1 concave region 2c2 convex region 3 polishing cloth 4 surface plate 5 substrate holder 6 slurry 7 slurry introducing pipe 8 laminated polishing cloth 8a filler-containing polishing cloth 8b none Filled polishing cloth

Claims (10)

[Claims] 1. A polishing cloth attached to a surface plate and used for polishing a substrate, wherein the polishing cloth contains an inorganic filler. 2. The inorganic filler is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt, a metal halide, a metal perchlorate, a metal silicate, a metal borate, a metal phosphate, or a metal arsenite. The polishing cloth according to claim 1, which is at least one kind of salt. 3. The polishing cloth according to claim 1, wherein the surface of the inorganic filler is coated with an organic silicon compound. 4. A polishing cloth attached to a surface plate and used for polishing a substrate, wherein the polishing cloth contains an organic filler. 5. The polishing cloth according to claim 4, wherein the organic filler is at least one of polyimide, polystyrene, and benzoguanamine. 6. A method of manufacturing a polishing cloth, which is attached to a surface plate and used for polishing a substrate, comprising the steps of adding an inorganic filler to a constituent resin of the polishing cloth, and shaping the polishing cloth into a shape. And a method for manufacturing a polishing cloth. 7. The inorganic filler is a metal carbonate, a metal sulfate, a metal nitrate, a metal ammonium salt, a metal halide, a metal perchlorate, a metal silicate, a metal borate, a metal phosphate, or a metal arsenite. The method for producing a polishing pad according to claim 6, wherein the polishing pad is at least one kind of salt. 8. The method for producing a polishing pad according to claim 6, wherein the surface of the inorganic filler is coated with an organic silicon compound. 9. A method of manufacturing a polishing cloth attached to a surface plate and used for polishing a substrate, the step of adding an organic filler to a constituent resin of the polishing cloth, and the step of molding the polishing cloth into a shape. And a method for manufacturing a polishing cloth. 10. The method of manufacturing a polishing cloth according to claim 9, wherein the organic filler is at least one of polyimide, polystyrene, and benzoguanamine.