JP3258427B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for 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. Things.

[0002]

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

The characteristics required for an interlayer insulating film for a submicron device include forming a space on the order of submicrons and achieving excellent step coverage for a pattern having a high aspect ratio. As a method of forming an interlayer insulating film satisfying such a requirement, a chemical vapor deposition method (CVD method) using organic silane and inorganic silane as a source gas is known. Also, CVD
Methods include plasma CVD, normal pressure CVD, low pressure CVD,
A pressurized CVD method, a photo-excited CVD method and the like have been conventionally proposed.

Of these, an insulating film formed by using an atmospheric pressure CVD method by adding an ozone gas to an organic silane as a raw material gas, that is, an atmospheric pressure ozone-organosilane CVD silicon oxide film has particularly excellent flatness. Is one of the most promising methods. A normal pressure CVD method using such an ozone-organosilane mixed gas is disclosed in, for example,
No. 61-77695 and `` Electrochemistry '' 56, No. 7 (1988), 527-
It is described on page 532 and so on. TEOS as organic silane
(tetraethoxysilane), TMOS (tetramethoxysilane), OMCT
S (octamethylcyclotetrasiloxane), HMDS (hexamethyldi
siloxane) is known.

[0005] In addition, with the increase in integration and density of VLSI devices, there is also a strong demand for an insulating film used as a final protective film to improve its flatness and film quality which affects device reliability. I have. 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 of forming an insulating film by a CVD method using organic silane as a raw material gas, depending on the base material, the step difference (between wirings) depends on the base material due to the film formation rate. Has the drawbacks that the embedding property is deteriorated and voids are generated in the film. In particular, as the element structure is miniaturized, a step having a large aspect ratio is formed, so that the possibility that such voids are generated increases. The fact that the organosilane-CVD film has a large underlayer dependency as described above
For example, "IEEJ Technical Paper A" published in 1991, 111
Vol. 7, pages 652-658. When the burying property is deteriorated or a void is formed as described above, a leak current between wirings is increased, which adversely affects device characteristics.

Further, a conventional CVD film using an organic silane has a large amount of a carbon compound containing water and the like (unreacted material) in the film.
Has the disadvantages that the film quality is poor, the moisture absorption resistance is poor, and cracks occur. If the film is made thick to compensate for the moisture absorption resistance, cracks are more likely to occur in the film, and there is a disadvantage that the reliability of the element is impaired.

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

As a method of planarizing the second interlayer film, a method of reacting an organic compound of silicon, such as a silicate, with ozone has been developed as a CVD method having self-flatness to fill a narrow gap. 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 affected by the underlying state. In addition, there is a problem that there is a so-called pattern dependency, in which the deposited film thickness varies depending on the density of the pattern, and global complete flattening cannot be achieved.

An object of the present invention is to eliminate the above-mentioned drawbacks, to eliminate the surface dependency of the underlayer by treatment with a solution of an organic compound, and to eliminate the pattern dependency by chemical mechanical polishing. It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of forming a highly flat interlayer insulating film having good characteristics.

[0011]

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: treating a film-forming base with a solution of an organic compound; and subjecting the organic silicon compound and ozone-containing oxygen to a normal pressure or reduced pressure thermal CVD method. And a step of polishing and flattening the insulating film by a chemical mechanical polishing method.

[0012]

According to the present invention, the dependence of the film quality and embedment on the underlying surface is eliminated by treatment with a solution of an organic compound, and the pattern dependence is eliminated by chemical mechanical polishing, resulting in good film quality and good embedment. Thus, a completely flat interlayer insulating film can be formed.

The organic compounds include aliphatic saturated monohydric alcohols, aliphatic unsaturated monohydric alcohols, aromatic alcohols, aliphatic saturated polyhydric alcohols and derivatives thereof, aldehydes, ethers, ketone and keto alcohols. Carboxylic acid, nitroalkane, amine, acylnitrile, acid amide, and heterocyclic compound, and specifically, the following substances can be 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 -Butyn-2-ol aromatic alcohols: benzyl alcohol, furfuryl alcohol, aliphatic saturated polyhydric alcohols and derivatives thereof: 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 and keto alcohol: acetone, 2-butanone, diacetone alcohol, γ-butyrolactone, propylene carboxylic acid: 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 acylnitrile: 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 preferred.

The following compounds can be used as the organosilane compound. Organic silane tetraalkoxysilane (orthosilicate): tetramethoxysilane, tetraethoxysilane, tetran
Propoxysilane, tetraisopropoxysilane, tetran-butoxysilane Alkylalkoxysilane: methyltrimethoxysilane, methyltriethoxysilane, methyltrinpropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrinpropoxy Silane, ethyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldiisopropoxysilane , Methylvinyldimethoxysilane, methylvinyldiethoxysilane methyldimethoxysilane, methyldiethoxysilane Orchid 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 trimethylsilyl azide, trimethylsilyl cyanide 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 as a mixture of two or more substances. When mixed, the mixing ratio may be appropriately controlled.

The surface treatment includes a coating treatment with the organic compound or an aqueous solution or an organic solvent solution thereof.
Or immersion treatment in the organic compound or an organic solvent solution thereof, or exposure treatment with vapor of the organic compound or the organic solvent solution, spray treatment, shower treatment, etc., and a coating treatment 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 source gas-CVD method
An SiO ₂ film is formed.

According to the method of manufacturing a semiconductor device according to the present invention, a CV having an organic silane compound as a source gas is used.
Before forming an insulating film by Method D, treat the underlying surface with the above-mentioned organic compound or its aqueous solution or organic solvent solution.
(Hereinafter also referred to as organic substance treatment) can greatly reduce the dependence on the underlying layer by performing a very simple treatment, and has an excellent film quality with excellent embedding and flatness and no cracks or voids. Since a film can be formed and the underlying treatment is as simple as treatment with an organic compound, the manufacturing apparatus is simplified and the throughput is improved.

The organic material treatment of the underlayer surface includes spin coating (coating treatment) in which the semiconductor wafer is applied while spinning, vapor treatment in which the vapor of an organic compound is sprayed on the semiconductor wafer, and immersion of the semiconductor wafer 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 all of them can be easily carried out.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
FIG. 1 shows the structure of an example of an apparatus which can be used as an apparatus for forming an organic silane-CVD film in an embodiment of a method of manufacturing a semiconductor device according to the present invention described below. A heater 2 is provided inside the reaction chamber 1 to heat a silicon wafer 4 supported by a susceptor 3. Further, an ozone generator 5 and a thermostat 6 are provided outside the reaction chamber 1, and a gas bubbler 7 is disposed inside the thermostat. Oxygen gas is supplied to the ozone generator 5 to generate ozone. The ozone generation rate of the ozone generator 5 is 4.0%. Nitrogen gas is supplied to the gas bubbler 7 disposed in the constant temperature bath 6,
An organic silane contained in a gas bubbler, in this case, TEOS gas is generated. The TEOS gas is supplied to the reaction chamber 1 together with the ozone generated by the ozone generator 5 using the 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 over 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 uniformity of film formation.

(Example 1) As shown in FIG. 2, a 1 μm thick BPSG film 12 is formed on an 8-inch silicon wafer 11, and a 1 μm thick metal film, ie, an aluminum film is formed thereon. By laminating and etching, the first wiring has a pattern interval of 0.5 μm, a groove depth of 1.1 μm, and a groove width of 0.5.
A μm aluminum pattern 13 was formed. After cleaning the wafer 11 with pure water, plasma-TEOS CVD NS, which is a silicon oxide film having a thickness of 300 nm, is formed by a 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 an organic compound solution, for example, with ethanol. In the ethanol treatment of this example, a silicon wafer was placed on a spin coater, and 3 ml of ethanol was dropped within 1 second while rotating at 3000 rpm, and the mixture was kept as it was for 3 minutes and dried.

Next, the silicon wafer thus dried is carried into the reaction chamber 1 shown in FIG.
A film was 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 thickness of μm.

[Table 1] Deposition temperature 400 ° C Deposition pressure Atmospheric pressure Deposition 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 formed in this manner fills a narrow space between the densely arranged aluminum wirings 13 and has a good step coverage, as is clear from FIG. In addition, the self-flatness was excellent, no voids were formed, the coverage and embedding properties were good, and the film had good water permeability and good film quality with low content.

As described above, the O ₃ -TEOS film 15 formed as described above has good flatness in the dense portion of the underlying pattern, but has poor flatness in the portion of the rough underlying pattern. , A concave portion is formed.

According to the present invention, as shown in FIG.
Plasma C using TEOS as a raw material on the O ₃ -TEOS film 15
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 residual step was observed. Also,
Fluctuations in film thickness and flatness were small over the entire surface of the wafer, and all were uniform at 0.05% or less.

In this case, the steps were completely buried, and the water content of the film was less than 1.0%, which was good.

[0026]

As described above, according to the present invention, the surface dependence of the underlayer is eliminated by the treatment with the organic compound solution, and the pattern dependence is eliminated by the chemical mechanical polishing.
A completely flat interlayer insulating film having good film quality and good embedding property was able to be formed.

[Brief description of the drawings]

FIG. 1 shows a method of manufacturing a semiconductor device according to the present invention.
FIG. 3 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 illustrating 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 illustrating a process of manufacturing a semiconductor device formed by the method of manufacturing a semiconductor device according to the present invention.

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Heater 3 Susceptor 4 Silicon wafer 5 Ozone generator 6 Constant temperature bath 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

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-30433 (JP, A) JP-A-5-13407 (JP, A) JP-A-4-94539 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/3205 H01L 21/3213 H01L 21/768

Claims (1)

(57) [Claims] A step of treating an underlayer with a solution of an organic compound; a step of depositing an oxide film by a normal pressure or reduced pressure thermal CVD method of an organic silicon compound and oxygen containing ozone; Polishing the insulating film by a polishing method to planarize the insulating film.