JPH06310503A - Method of manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To form a complete flat interlayer insulation film having a good film quality and a good implantation characteristic by removing surface dependence of a groundwork by treating with an organic compound solution and also by removing pattern dependence by chemical mechanical grinding. CONSTITUTION:Film-forming groundworks 13, 14 are treated with an organic compound solution and an oxide, film 15 is accumulated by a normal pressure or reduced pressure thermal CVD method of an organic silicon compound and oxygen containing ozone and the insulation film 15 is ground and flatted by a chemical mechanical grinding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device,
In particular, the present invention relates to a method for forming a primary insulating film between a semiconductor substrate and a metal wiring, an interlayer insulating film between metal wirings, and a final insulating film acting as a passivation film by chemical vapor deposition using an organic silane compound as a source gas. It is a thing.

[0002]

2. Description of the Related Art In recent years, high integration and high density of VLSI devices have been rapidly advanced, and submicron processing has become essential in semiconductor processing technology. As the submicron processing progresses, the unevenness of the semiconductor substrate surface becomes more and more intense,
The aspect ratio becomes large, and this unevenness becomes a constraint in device manufacturing. What is most strongly desired for solving such a problem is a planarization technique for an interlayer insulating film.

Characteristics required for the interlayer insulating film for submicron devices include forming a space of submicron order and achieving excellent step coverage for a pattern having a high aspect ratio. A chemical vapor deposition method (CVD method) using organic silane and inorganic silane as a source gas is known as a method of forming an interlayer insulating film satisfying such requirements. Also, CVD
Plasma CVD method, atmospheric pressure CVD method, low pressure CVD method,
The pressure CVD method and the photo-excited CVD method have been proposed in the past.

Among these, an insulating film formed by an atmospheric pressure CVD method using an organic silane as a raw material gas and adding ozone gas thereto, that is, an atmospheric pressure ozone-organic silane CVD silicon oxide film is particularly excellent in flatness. This is one of the most expected methods of being able to do so. An atmospheric pressure CVD method using such a mixed gas of ozone-organosilane is disclosed in
No. 61-77695 or "Electrochemistry" 56, No. 7 (1988), 527-
It is described on page 532. TEOS as an organic silane
(tetraethoxysilane), TMOS (tetramethoxysilane), OMCT
S (octamethylcyclotetrasiloxane), HMDS (hexamethyldi
Siloxane) is known.

Further, with respect to the insulating film used as the final protective film, it is strongly demanded that the flatness thereof and the film quality which affects the reliability of the device are improved with the high integration and high density of VLSI devices. There is. This is mainly to prevent intrusion of moisture or the like from the side wall of the final wiring.

[0006]

However, in the conventional method for forming an insulating film by the CVD method using organic silane as a raw material gas, there is a gap between steps (between wirings) depending on the substrate material due to the substrate dependency of the film formation rate. However, there is a drawback in that the embedding property of is deteriorated and a void is generated in the film. In particular, since a step having a large aspect ratio is formed as the element structure is miniaturized, such a void is more likely to be generated. Thus, the fact that the organosilane-CVD film has a large base dependency
For example, “The Institute of Electrical Engineers of Japan A”, 111, published in 1991.
Vol. 7, pp. 652-658. When the embedding property deteriorates or voids are formed in this way, the leak current between the wirings increases and the device characteristics are adversely affected.

Further, the conventional CVD film using organic silane has a large amount of carbon compounds (unreacted substances) containing water etc. in the film.
However, there is a defect that the film quality is poor, the moisture absorption resistance is poor, and cracks occur. If a thick film is used to supplement the moisture absorption resistance, cracks are more likely to occur in the film, which has the drawback of impairing the reliability of the device.

In order to reduce the above-mentioned drawbacks of the conventional method of forming an insulating film, the plasma oxide film on the base surface is replaced with N2, NH3.
It has been proposed to perform a plasma treatment using a gas such as the above, and then form an atmospheric pressure CVD film using organosilane.
There is concern about the problem of plasma damage.

As a method of flattening the second interlayer film, a method of reacting an organic compound of silicon such as silicate ester with ozone as a CVD method having self-flatness for filling a narrow gap has been developed. However, there is a problem that a good film is not formed because the film quality, the film forming speed, and the embedding property are strongly influenced by the underlying state. In addition, there is a problem that the film thickness to be deposited varies depending on the density of the pattern, that is, there is so-called pattern dependency, and global perfect flatness cannot be achieved.

The object of the present invention is to eliminate the above-mentioned drawbacks, to eliminate the surface dependency of the underlying layer by treatment with a solution of an organic compound, and to eliminate the pattern dependency by chemical mechanical polishing. Another object of the present invention is to provide a method for manufacturing a semiconductor device, which is capable of forming a completely flat interlayer insulating film having good properties.

[0011]

A method of manufacturing a semiconductor device according to the present invention comprises a step of treating a film-forming base with a solution of an organic compound, and a thermal CVD method of oxygen containing an organic silicon compound and ozone at atmospheric pressure or reduced pressure. And a step of polishing the insulating film by a chemical mechanical polishing method to planarize the insulating film.

[0012]

According to the present invention, the dependency of the film quality and the embedding property on the underlying surface is eliminated by the treatment with the solution of the organic compound, and the pattern dependency is eliminated by the chemical mechanical polishing, so that the film quality is good and the embedding property is good. A completely flat interlayer insulating film can be formed.

Examples of the organic compound include aliphatic saturated monohydric alcohols, aliphatic unsaturated monohydric alcohols, aromatic alcohols, aliphatic saturated polyhydric alcohols and their derivatives, aldehydes, ethers, ketones and keto alcohols. , Carboxylic acids, nitroalkanes, amines, acylnitriles, acid amides, and heterocyclic compounds, and the following substances can be specifically used. Aliphatic saturated monohydric alcohols: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 2-methyl-2-propanol, 1-pentanol, 3 -Methyl-1-butanol, 3-methyl-2-butanol, 2-methyl-2-butanol, 1-hexanol, cyclohexanol Aliphatic unsaturated monohydric alcohols: allyl alcohol, propargyl alcohol, 2-methyl-3 -Butin-2-ol aromatic alcohols: benzyl alcohol, furfuryl alcohol, aliphatic saturated polyhydric alcohols and their derivatives: ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Chi glycol monobutyl n-butyl ether, ethylene glycol monoisobutyl ether, propylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether aldehydes: formaldehyde, acetaldehyde, glyoxal ether: diethyl ether, dioxane, tetrahydrofuran,
Tetrahydrofurfuryl alcohol ketone / keto alcohol: Acetone, 2-butanone, diacetone alcohol, γ-butyrolactone, propylene carbonate carbonate: formic acid, acetic acid, propionic acid, glycolic acid, lactic acid, ethyl lactate Nitroalkane: nitromethane, nitroethane, nitropropane , Nitrobenzene amine: ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, allylamine, aniline, toluidine, ethylenediamine, diethylamine, ethyleneimine, dipropylamine, diisopropylamine, dibutylamine, triethylamine,
Tri-n-propylamine, tri-n-butylamine acyl nitriles: acetonitrile, propiononitrile, butyronitrile, acrylonitrile, methacrylonitrile, benzonitrile Acid amide: formamide, N-methylformamide,
N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, heterocyclic compound: pyridine, quinoline, pyrrole, piperidine, piperazine, morpholine, 2-pyrrolidinone,
1-Methyl-2-pyrrolidinone However, lower alcohols and acetylene alcohols are particularly preferable.

The following compounds can be used as the organic silane compound. Organic silane Tetraalkoxy silane (orthosilicate ester): tetramethoxysilane, tetraethoxysilane, tetra-n
Propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane Alkylalkoxysilane: methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxy Silane, ethyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldiisopropoxysilane , Methylvinyldimethoxysilane, methylvinyldiethoxysilane methyldimethoxysilane, methyldiethoxy Run Dimethylvinylmethoxysilane, Dimethylvinylethoxysilane Polysiloxane: Tetrakis (dimethylsiloxy) silane Cyclosiloxane: Octamethylcyclotetrasiloxane, pentamethylcyclotetrasiloxane, Tetramethylcyclotetrasiloxane, Hexamethylcyclotrisiloxane, Trimethylcyclotrisiloxane Disiloxane: hexamethyldisiloxane, tetramethyldimethoxydisiloxane, dimethyltetramethoxydisiloxane, hexamethoxydisiloxane Alkylsilane: monomethylsilane, dimethylsilane,
Trimethylsilane, triethylsilane, tetramethylsilane, tetraethylsilane allyltrimethylsilane hexamethyldisilane silylamine: dimethyltrimethylsilylamine, diethyltrimethylsilylamine silane nitrogen derivative: aminopropyltriethoxysilane trimethylsilylazide, trimethylsilylcyanide silazane: hexamethyldisilazane, tetra Methyldisilazane Octamethylcyclotetrasilazane, Hexamethylcyclotrisilazane Halogenated silanes and derivatives: trimethylchlorosilane, triethylchlorosilane, tri-n-propylchlorosilane, methyldichlorosilane, dimethylchlorosilane,
Chloromethyldimethylchlorosilane, chloromethyltrimethylsilane, chloropropylmethyldichlorosilane,
Chloropropyltrimethoxysilane dimethyldichlorosilane, diethyldichlorosilane, methylvinyldichlorosilane, methyltrichlorosilane,
Ethyltrichlorosilane, vinyltrichlorosilane, trifluoropropyltrichlorosilane, trifluoropropyltrimethoxysilane, trimethylsilyl iodide,

In the present invention, the above-mentioned organosilane compounds can be used alone or in combination of two or more substances. When mixed and used, the mixing ratio may be appropriately adjusted.

As the surface treatment, the organic compound or its aqueous solution or organic solvent solution is applied.
Alternatively, the organic compound or its organic solvent solution may be dipped, or the organic compound or its organic solvent solution may be exposed to steam, sprayed, showered, or the like, but coating using a spin coater is particularly preferable. . In the preferred embodiment of the present invention, in forming an insulating film which acts as an interlayer insulating film of a semiconductor device, a plasma -CVD-SiO ₂ film was formed as a base, the surface after the ethanol treatment by a spin coater, Atmospheric pressure ozone using TEOS as raw material gas-By CVD method
A SiO ₂ film is formed.

According to the method for manufacturing a semiconductor device of the present invention as described above, CV using an organic silane compound as a source gas is used.
Before forming the insulating film by method D, treat the underlying surface with the above-mentioned organic compound or its aqueous solution or organic solvent solution.
By performing a very simple process (hereinafter also referred to as organic substance treatment), the dependency on the underlayer can be significantly eased, and the insulating property is excellent in embedding property and flatness and has no cracks or voids. Since a film can be formed and the base treatment is a simple treatment of an organic compound, the manufacturing apparatus is simplified and the throughput is improved.

The organic substance treatment on the surface of the base is spin coating (coating treatment) in which the semiconductor wafer is applied while being spun, vapor treatment in which the vapor of an organic compound is sprayed onto the semiconductor wafer, and the semiconductor wafer is immersed in a solution of the organic compound. Various treatment methods such as a dipping treatment, a spray treatment for spraying a solution of an organic compound, and a curtain coating treatment for passing a semiconductor substrate through a shower of an organic compound are possible, but any of them can be easily performed.

[0019]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
Shows the constitution of an example of an apparatus which can be used as an apparatus for forming an organosilane-CVD film in the embodiment of the method for manufacturing a semiconductor device according to the present invention described below. A heater 2 is provided inside the reaction chamber 1 to heat the silicon wafer 4 supported by the susceptor 3. Further, an ozone generator 5 and a constant temperature bath 6 are provided outside the reaction chamber 1, and a gas bubbler 7 is placed inside the constant temperature bath. Ozone gas is supplied to the ozone generator 5 to generate ozone. The ozone generation rate of this ozone generator 5 is 4.0%. Nitrogen gas is supplied to the gas bubbler 7 arranged in the constant temperature bath 6,
Organosilane contained in the gas bubbler, in this example, TEOS gas is generated. This TEOS gas is supplied to the reaction chamber 1 together with ozone generated by the ozone generator 5 using nitrogen gas as a carrier gas. A dispersion head 8 is arranged in the reaction chamber 1, and a mixed gas of ozone and TEOS gas is applied as a laminar flow to the surface of the silicon wafer 4 so that a uniform film is formed on the entire surface of the silicon wafer. To Further, for this purpose, the silicon wafer 4 is swung in the plane together with the heater 2 and the susceptor 3 to ensure the uniformity of film formation.

(Embodiment 1) As shown in FIG. 2, a BPSG film 12 having a thickness of 1 μm is formed on an 8-inch silicon wafer 11, and a metal film having a thickness of 1 μm, that is, an aluminum film is formed on the BPSG film 12. By stacking and etching, pattern spacing of 0.5 μm, groove depth of 1.1 μm, groove width of 0.5
A μm aluminum pattern 13 was formed. After cleaning this wafer 11 with pure water, plasma-TEOS CVD NS which is a silicon oxide film with a thickness of 300 nm is formed by the plasma CVD method using TEOS as a raw material.
A G film 14 was formed.

Next, the surface of the plasma-TEOS CVD NSG film 14, which is the base of the silicon wafer, was treated with a solution of an organic compound, for example, a base treatment with ethanol. In the ethanol treatment of this example, a silicon wafer was placed on a spin coater, 3 ml of ethanol was added dropwise within 1 second while rotating at 3000 rpm, and kept for 3 minutes to dry.

Then, the thus dried silicon wafer is loaded into the reaction chamber 1 shown in FIG.
Film is formed under the following conditions using various source gases by the method, and an ozone-TEOS CVD PSG film 15 as shown in FIG.
It was formed to a film thickness of μm.

[Table 1] Film formation temperature 400 ℃ Film formation pressure Atmospheric pressure Film formation time 545 seconds Nitrogen gas flow to gas bubbler 1.5l / min Constant temperature bath temperature 65 ℃ Oxygen flow to ozone generator 7.5l / min Ozone concentration 120g / m ³ Carrier N ₂ 2 slm The ozone-TEOS CVD PSG film 15 thus formed fills the narrow space between the densely arranged aluminum wirings 13 and has good step coverage, as is clear from FIG. In addition, it was excellent in self-flatness, had no voids formed, had good coverage and embeddability, and had a good film quality with low water permeability and low content.

As described above, the O ₃ -TEOS film 15 thus formed has good flatness in the dense part of the base pattern, but the flatness is impaired in the rough part of the base pattern. , So that a concave portion is formed.

According to the present invention, as shown in FIG.
On top of the O ₃ -TEOS film 15, plasma C using TEOS as a raw material is further added.
A silicon oxide film 16 having a thickness of 500 nm was formed by the VD method. After this,
When the surface was polished for about 1200 nm by the chemical mechanical polishing method, no step difference was observed. Also,
The variations in film thickness and flatness were small over the entire surface of the wafer, and both were uniform at 0.05% or less.

In this case, the step was completely filled, and the moisture content of the film was as good as 1.0% or less.

[0026]

As described above, according to the present invention, the surface dependency of the underlayer is eliminated by the treatment with the organic compound solution, and the pattern dependency is eliminated by the chemical mechanical polishing.
It was possible to form a completely flat interlayer insulating film having good film quality and good burying property.

[Brief description of drawings]

FIG. 1 shows a method of manufacturing a semiconductor device according to the present invention,
It is a diagram showing a configuration of a chemical vapor deposition apparatus for forming an ozone-organosilane CVD film.

FIG. 2 is a cross-sectional view showing a manufacturing process of a semiconductor device formed by a method of manufacturing a semiconductor device according to the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of a semiconductor device formed by a method of manufacturing a semiconductor device according to the present invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of a semiconductor device formed by a method of manufacturing a semiconductor device according to the present invention.

FIG. 5 is a cross-sectional view showing a manufacturing process of a semiconductor device formed by the method of manufacturing a semiconductor device according to the present invention.

[Explanation of symbols]

 1 Reaction Chamber 2 Heater 3 Susceptor 4 Silicon Wafer 5 Ozone Generator 6 Constant Temperature Chamber 7 Gas Bubbler 8 Dispersion Head 11 Wafer 12 BPSG Film 13 Al Wiring 14 Plasma-TEOS CVD NSG Film 15 Ozone-TEOS CVD PSG Film 16 Silicon Oxide Film

Claims (1)

[Claims] 1. A step of treating a film-forming base with a solution of an organic compound, a step of depositing an oxide film by a thermal CVD method of oxygen containing an organosilicon compound and ozone at atmospheric pressure or reduced pressure, and chemical mechanical And a step of polishing the insulating film by a polishing method to planarize the insulating film.