JPH06283515A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve more the substrate dependency of a film-forming rate and the burying properties between steps, in particular, to facilitate the formation of the insulating film of a submicron order device by a method wherein a substrate surface is treated with a treating fluid containing an organic compound, then, the substrate surface is treated with plasma and after that, the insulating film is formed by a CVD method. CONSTITUTION:In the case where an insulating film 14 of a semiconductor device is formed by a chemical vapor deposition method, a substrate surface is treated with a treating fluid containing an organic compound, pound, then, the substrate surface is treated with plasma and after that, the film 14 is formed by the chemical vapor deposition method. As the treating fluid containing the organic compound, an alcohol of 5 or less carbon atoms and the like are used and it is suitable to perform the plasma treatment using ammonia plasma or nitrogen plasma. For example, Al wirings 12 are formed on an Si substrate 11 and a plasma-TEOS CVD NSG film 13 is formed thereon. Then, the surface of the film 13 is subjected to ethanol treatment and moreover, after a plasma irradiation treatment is performed, an ozone-TEOS CVD NSG film 14 is formed.

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, a primary insulating film between the semiconductor substrate and the first layer metal wiring,
The present invention relates to a method for forming a final insulating film that acts as an interlayer insulating film between metal wirings and a passivation film and an insulating film that can be used as a sidewall of a gate of a field effect transistor by chemical vapor deposition.

[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 an organic silane and an inorganic silane as a source gas is known as a method of forming an interlayer insulating film satisfying such requirements. As the CVD method, plasma CVD, atmospheric pressure CVD method, low pressure CVD method, pressurized CV
The D method and the photo-excited CVD method have been proposed in the past.

Of these, using organic silane as a source gas,
The insulating film formed by atmospheric pressure CVD method by adding ozone gas to it, that is, the atmospheric pressure ozone-organosilane CVD silicon oxide film is one of the most promising methods because of its excellent flatness. . An atmospheric pressure CVD method using such a mixed gas of ozone and organosilane is disclosed in, for example, Japanese Patent Laid-Open No.
-77695 or "Electrochemistry" 56, No. 7 (1988), 527-53
It is described on page 2. TEOS (t
etraethoxyorthosilicate), TMOS (tetramethoxyorthosi
licate), OMCTS (octamethylcyclotetrasiloxane), HMDS
(hexamethyldisiloxane), TMCTS (tetramethylcyclotetr
asiloxane), SOB (trimethylsilyl borate), DADBS (diace
toxydi-tertiary-butoxysilane), SOP (trimethylsilyl
phosphate) is known.

Also in the insulating film used as the final protective film, it is strongly demanded to improve the film quality which affects the coverage characteristic and flatness and the reliability of the element as the VLSI device becomes highly integrated and has a high density. Has been done. This is mainly to prevent intrusion of moisture and the like from the outside of the element.

[0006]

However, in the conventional method of forming an insulating film by the CVD method using organic silane as a raw material gas, the characteristics of the insulating film are significantly deteriorated or the gap between the steps ( The embeddability (between wirings) is significantly deteriorated. In particular, in the CVD method using TEOS and ozone as source gases, there are problems such as a decrease in the density of the insulating film to be formed, an increase in the etching rate, and an increase in the leak current depending on the formation conditions of the underlying layer. Occurs,
There is a possibility that good insulation characteristics may not be obtained. Also,
The film formation rate depends on the underlying layer, and the film formation rate differs between a dense step pattern and a sparse step pattern, causing the problem that the step difference on the substrate after forming the insulating film becomes large on the contrary. There is. Further, in the case of a step pattern having an aspect ratio of the step greater than about 2, there is a drawback that the steps are not completely filled and voids are generated between the steps.

As a method for solving such a problem,
For example, 16 of the proceedings of the 1992 Spring Applied Physics Society
p-2Q-6 and the magazine "Technical" published in 1989.
As described in "Digest Electron Devices Meeting", p. 669, a method of plasma-treating an underlayer and then forming an organosilane-CVD film has been proposed. However, according to this method, the dependency of the film formation rate on the underlying layer is eliminated, but the filling property between the steps is further deteriorated.

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks, to further improve the underlying dependency of the film formation rate and the embedding property between steps, and particularly to a semiconductor suitable for forming an insulating film of a submicron device. It is to provide a method of manufacturing a device.

[0009]

In the method of manufacturing a semiconductor device according to the present invention, in forming an insulating film of a semiconductor device by chemical vapor deposition, the underlying surface is treated with a treatment fluid containing an organic compound, and then, The base surface is treated with plasma, and then an insulating film is formed by chemical vapor deposition.

By treating the underlayer surface with a treatment fluid containing an organic compound such as methanol or ethanol, the organic compound is uniformly adsorbed on the underlayer surface, and an insulating film formed by CVD using ozone and TEOS as source gases is used. The embeddability in the forming process can be further improved. Since the fluid treatment containing the organic compound is described in detail in Japanese Patent Application No. 5-52412 proposed by the present applicant,
See the publication of this patent application.

In the fluid treatment containing the organic compound, the filling performance between the steps is improved, but the difference in film forming speed due to the step pattern tends to increase, and therefore the flatness of the entire wafer is improved. There is a need. On the other hand, as described above, in the manufacturing method in which the plasma treatment is performed before forming the CVD film, the difference in film forming speed due to the step is reduced, but the filling performance in the step pattern with a high aspect ratio is insufficient, If the ratio is 1.5 or more, a void will occur.

Therefore, in the present invention, after the surface of the underlayer is subjected to the fluid treatment with the organic compound, the plasma treatment is further performed, and then the insulating film is formed by the CVD method. If the underlying surface is treated with a treatment fluid containing an organic compound, the treatment fluid can enter even between steps having a large aspect ratio.
On the other hand, in the case of plasma treatment, active radicals or ions are less likely to enter between narrow steps, and the effect is limited to a wide flat base surface. Therefore, it is presumed that the fluid treatment with the organic compound is extremely effective for the step pattern having a large aspect ratio and dense, and the plasma treatment is effective for the underlying surface having a small aspect ratio and the step pattern being sparse. Therefore, by using both the fluid treatment with the organic compound and the plasma treatment, both the embedding property between the steps and the flattening can be sufficiently achieved even on the base surface having a portion with a large aspect ratio and a portion with a small aspect ratio. be able to.

In the present invention, it is preferable that the insulating film is formed by chemical vapor deposition using organic silane as a raw material. Examples of the organic silane include TEOS, TMOS, OMCTS, HMDS, SOB, DADBS or SOP described above.
However, other silane compounds can also be used as raw materials. Furthermore, in the method of manufacturing a semiconductor device according to the present invention, the organic compound of the processing fluid is an OH group,
It is preferable to use an organic compound or a heterocyclic compound having a functional group of at least one of CO group, COC group, CN group, NO ₂ group and NR (R = H or alkyl group). Among these organic compounds, alcohol having an OH group, particularly ethanol or methanol is preferable. Also,
An aqueous solution of an organic compound or an organic solvent solution can also be used as the processing fluid. Further, as in Examples described later, a base insulating film is formed before forming the insulating film by chemical vapor deposition, and the base insulating film is treated with a processing fluid or a polysilicon pattern is formed, and the surface thereof is formed. Can be treated with a treatment fluid.

As described above, as the organic compound for performing the surface treatment, aliphatic saturated monohydric alcohols, aliphatic unsaturated monohydric alcohols, aromatic alcohols, aliphatic saturated polyhydric alcohols and the like. Derivatives, aldehydes, ethers, ketones / keto alcohols, carboxylic acids,
Nitroalkane, amine, acyl nitrile, acid amide,
Examples of the heterocyclic compound include the following substances. Aliphatic saturated monohydric alcohol (OH group): 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 (OH group): allyl alcohol, propargyl alcohol, 2-methyl-3-butyn-2-ol aromatic alcohol Group (OH group): Benzyl alcohol, furfuryl alcohol Aliphatic saturated polyhydric alcohols and their derivatives (OH group):
Ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-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 Aldehyde (CO group): Formaldehyde, acetaldehyde, glyoxal ether (COC group): Diethyl ether, dioxane, tetrahydrofuran, tetrahydrofurfuryl alcohol Ketone / keto alcohol (CO group): Acetone, 2-butanone, diacetone alcohol, γ-butyrolactone, propylene carbonate carboxylic acid (CO group): formic acid, acetic acid, propionic acid, glycolic acid, lactic acid, ethyl lactate nitroalkane (NO ₂ group): nitromethane, nitroethane, nitropropane, nitrobenzene Amine (NR: R = H) ethylamine, propylamine, isopropylamine,
Butylamine, isobutylamine, allylamine, aniline, toluidine, ethylenediamine, diethylamine, ethyleneimine, dipropylamine, diisopropylamine, dibutylamine, triethylamine, tri-n
Propylamine, tri-n-butylamine acyl nitriles (CN group): acetonitrile, propiononitrile, butyronitrile, acrylonitrile, methacrylonitrile, benzonitrile acid amide (NR: R = alkyl group) 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 In the present invention, one kind of such organic compound may be subjected to a base treatment, or two or more kinds of organic compounds may be treated simultaneously or sequentially. Of these organic compounds, alcohols having 5 or less carbon atoms are particularly suitable.

The following compounds can be used as the organosilicon compound as a raw material when the insulating film is formed by chemical vapor deposition. Tetraalkoxysilane (orthosilicate ester): Tetramethoxysilane (TMOS), Tetraethoxysilane (TEO)
S), tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane alkylalkoxysilane: methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxy Silane, ethyltri-n-propoxysilane, ethyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane , Diethyldiisopropoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, methyldimethoxysilane, methyl Ludiethoxysilane, dimethylvinylmethoxysilane, dimethylvinylethoxysilane Polysiloxane: tetrakis (dimethylsiloxy) silane Cyclosixane: Octamethylcyclotetrasiloxane
(OMCTS), pentamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, trimethylcyclotrisiloxane disiloxane: hexamethyldisiloxane (HMDS), tetramethyldimethoxydisiloxane, dimethyltetramethoxydisiloxane, hexa Methoxydisiloxane Alkylsilane: monomethylsilane, dimethylsilane,
Trimethylsilane, triethylsilane, tetramethylsilane, tetraethylsilane, allyltrimethylsilane,
Hexamethyldisilane silylamine: dimethyltrimethylsilylamine, diethyltrimethylsilylamine Silane nitrogen derivative: aminopropyltriethoxysilane, trimethylsilylazide, trimethylsilylcyanide silazane: hexamethyldisilazane, tetramethyldisilazane, octamethylcyclotetrasilazane, hexamethylcyclotriazane Silazane halogenated silanes and derivatives: trimethylchlorosilane, triethylchlorosilane, tri-n-propylchlorosilane, methyldichlorosilane, dimethylchlorosilane,
Chloromethyldimethylchlorosilane, chloromethyltrimethylsilane, chloropropylmethyldichlorosilane,
Chloropropyltrimethoxysilane, dimethyldichlorosilane, diethyldichlorosilane, methylvinyldichlorosilane, methyltrichlorosilane, ethyltrichlorosilane, vinyltrichlorosilane, trifluoropropyltrichlorosilane, trifluoropropyltrimethoxysilane, trimethylsilyliodide In addition, organic As the silicon compound, tris (trimethylsiloxy) borane (SOB), tris (trimethylsiloxy) phosphoryl (SOP), diacetoxydi-tert-butoxysilane (DADBS) and the like can also be used. Of these organic silanes, tetraethoxysilane (TEOS) is particularly preferable because it has a high vapor pressure and can form an insulating film with good characteristics. In the present invention, the above-mentioned organosilicon compounds may be used alone, or two or more organosilicon compounds may be mixed and used. When mixed and used, the mixing ratio may be set appropriately.

As the surface treatment, a coating treatment of the organic compound or its aqueous solution or its organic solvent solution with a spin coater, or a dipping treatment, or an exposure treatment with the vapor of the organic compound or its aqueous solution or its organic solvent solution, Spray treatment, shower treatment, curtain flow coat treatment and the like can be mentioned. In a preferred embodiment of the present invention, in forming an insulating film that acts as an interlayer insulating film of a semiconductor device, a plasma-CVD TEOS NSG film is formed as a base, and the surface thereof is treated with ethanol by a spin coater, and then TEOS is formed.
AP O ₃ by the atmospheric ozone -CVD method used as a raw material gas -TE
Form an OS CVD NSG film.

An RF or microwave plasma source can be used as the plasma source for the plasma treatment, and ammonia, nitrogen, hydrogen, oxygen, helium, argon, or a mixed gas thereof is used as a gas for plasma generation. Can be used. In particular, it is extremely effective for ammonia plasma.

[0018]

EXAMPLES Examples and comparative examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a structure of an example of an apparatus for forming an organic silane-CVD film in an embodiment of a 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 to generate the organic silane, TEOS gas in this example, contained in the gas bubbler. 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.

2 (a) to 2 (c) are schematic sectional views showing a series of steps in the method for manufacturing a semiconductor device according to the present invention. As shown in FIG. 2A, an aluminum wiring 12 having a height of 1 μm was formed on a silicon substrate 11. As shown in Fig. 2 (b), plasma-TEOS C is placed on the silicon substrate and aluminum wiring.
The VD NSG film 13 was formed to a thickness of 3000Å. This plasma
The film formation temperature of the TEOS CVD NSG film 13 is 350.
C., the film formation pressure was 2.2 Torr, TEOS was supplied at a rate of 500 sccm, oxygen gas was supplied at a rate of 500 sccm, RF power was 500 W, and the film formation time was 20 seconds. The thickness of this plasma-TEOS CVD NSG film 13 is on the aluminum wiring 12.
Although it is 3000 Å, only about 1000 Å is formed on its side wall.

Next, the surface of the base of the silicon wafer was treated with ethanol. In the ethanol treatment of this example, a silicon wafer was placed on a spin coater, ethyl alcohol was applied at a flow rate of 100 ml / min for 10 seconds while rotating at 3000 rpm, and then dried at 2000 rpm for 60 seconds.

Next, the silicon ware was mounted in a plasma generator and plasma irradiation processing was performed. At the time of plasma generation, ammonia gas was supplied at a rate of 50 sccm, nitrogen gas was supplied at a rate of 2000 sccm, RF power was set to 600 W, and plasma was generated under these conditions.
The substrate heated to ℃ was irradiated with plasma for 1 minute.

Next, the silicon wafer was loaded into the reaction chamber shown in FIG. 1, and ozone-TEOS C was used under the following film forming conditions.
The VD NSG film 14 was formed to a film thickness of 8000 Å. In addition, in this specification, the gas flow rate indicates the flow rate in a standard state of 0 ° C. and 1 atm.

[Table 1] Film formation temperature 400 ℃ Film formation pressure Atmospheric pressure Film formation time 545 seconds Nitrogen gas flow to gas bubbler 1.5 l / min Constant temperature bath temperature 65 ℃ Oxygen flow to ozone generator 7.5 l / min Ozone concentration 5% by weight Carrier N ₂ gas flow rate 18 l / min Ozone-TEOS CVD NSG film 14 thus formed fills a narrow space between aluminum wirings 12, has good step coverage, and has excellent flatness, It had a good film quality with no voids formed.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made. For example, in the above-mentioned embodiment, the example of forming the TEOS CVD NSG film on the aluminum wiring has been described, but the present invention can be applied to the case where the organic silane CVD film is formed as the interlayer insulating film, and the final It can also be applied to the formation of a passivation film and the formation of a sidewall film on the side surface of a gate electrode of an FET, and also to the formation of polysilicon multilayer wiring.

Further, the metal constituting the conductive wiring is not limited to the above-mentioned embodiment, and for example, Al,
Cu, Mo, W, Ti, TiN, TiW or alloys thereof can also be used.

Further, in the above-mentioned embodiment, the ozone-TEOS CVD NSG film is formed after the ethanol treatment. However, TMOP (trimethylphosphate) and TMB (trimethy) are added to the mixed gas of ozone and TEOS supplied to the reaction chamber.
Ozone-TEOS CVDPSG by adding phosphorus and boron alkoxide gases such as
It is also possible to form a film or a BPSG film. Furthermore, not only TEOS but also the above-mentioned TMO is used as the organic silane raw material compound.
It is also possible to use S, OMCTS, HMDS, TMCTS, SOB, DADBS, SOP and the like.

[0026]

As described above, in the method of manufacturing a semiconductor device according to the present invention, the underlying surface is treated with the organic matter and the plasma treatment before the insulating film is formed by the chemical vapor deposition method. A step pattern with a high aspect ratio (aspect ratio of 3 or more), which could not be obtained in the past, can be embedded, and the dependency of the deposition rate of the CVD film on the underlayer can be eliminated, and a flatter insulating film can be formed. You can

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a series of steps in a method for manufacturing a semiconductor device according to the present invention.

[Explanation of symbols]

 11 Silicon substrate 12 Aluminum wiring 13 Plasma-TEOS CVD NSG film 14 Ozone-TEOS CVD NSG film

Claims (4)

[Claims] 1. When forming an insulating film of a semiconductor device by chemical vapor deposition, the underlayer surface is treated with a treatment fluid containing an organic compound, then the underlayer surface is treated with plasma, and then the insulating film is chemically treated. A method for manufacturing a semiconductor device, which is characterized by being formed by vapor phase growth. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the insulating film is formed by chemical vapor deposition using tetraethoxysilane as a raw material. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the processing fluid containing the organic compound is an alcohol having 5 or less carbon atoms. 4. A method of manufacturing a semiconductor device, wherein the plasma treatment is performed by an Annimore plasma or a nitrogen plasma.