JPH06268081A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an insulating film with excellent film quality for semiconductor devices which has favorable burying characteristics and contains no void. CONSTITUTION:Before forming an insulating film on the surface of a silicon wafer 11, the surface of the base is treated with organic compounds. After the treatments an insulating film 15 is formed by a reduced pressure chemical vapor deposition method. Treating the surface of the base with organic compounds, as mentioned above, will form a favorable insulating film which is excellent in burying characteristics and contains no void.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a method of manufacturing a semiconductor device, and more particularly, to be used as a primary insulating film between a semiconductor substrate and metal wiring, an interlayer insulating film between metal wirings, and a final insulating film acting as a passivation film. The present invention relates to a method for forming an insulating film which can be formed by chemical vapor deposition using an organic silicon compound as a source gas.

[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 an interlayer insulating film for submicron devices include forming a space on the order of submicrons 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 source gases is known as a method for forming an interlayer insulating film that satisfies such requirements. As the CVD method, plasma CVD, atmospheric pressure CVD method, low pressure CVD method, pressure CVD method
Methods and photo-excited CVD methods have been proposed.

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
etraethoxysilane), TMOS (tetramethoxysilane), OMCTS
(octamethylcyclotetrasiloxane), HMDS (hexamethyldis
iloxane), SOB (trimethylsilyl borate), DADBS (diace
toxydi-tertiary-butoxysilane), SOP (trimethylsilyl p
hosphate) etc. are 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 and the like from the outside of the element.

[0006]

However, in the conventional method for forming an insulating film by the CVD method using organic silane as a source 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. The fact that the organic silane-CVD film has a large underlayer dependency is described in, for example, "The Institute of Electrical Engineers of Japan", Vol. 111, No. 7, pp. 652-658, published in 1991. 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 underlying surface is replaced with N ₂ and NH ₃
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. Further, the plasma treatment does not improve the embedding property.

The object of the present invention is to solve the above-mentioned drawbacks of the conventional insulating film forming method, and is excellent in the filling property between steps and the elimination of voids in the film without plasma damage. It is an object of the present invention to provide an insulating film forming method which is effective for use as an insulating film, has excellent film quality, does not generate cracks, and can improve throughput by reducing the number of manufacturing steps.

[0010]

In the method of manufacturing a semiconductor device according to the present invention, when an insulating film is formed by chemical vapor deposition using an organic silicon compound as a raw material, a base surface on which the insulating film is to be formed is previously formed. It is characterized in that it is treated with an organic compound, and thereafter, the above-mentioned insulating film is formed by a low pressure chemical vapor deposition method.

The above-mentioned organic compounds include aliphatic saturated monohydric alcohols, aliphatic unsaturated monohydric alcohols, aromatic alcohols, aliphatic saturated polyhydric alcohols, aldehydes, ethers, ketones, carboxylic acids, nitroalkanes, amines, Examples thereof include acyl nitrile, 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 their derivatives: 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

Aldehydes: formaldehyde, acetaldehyde, glyoxal

Ether: Diethyl ether, dioxane, tetrahydrofuran, tetrahydrofurfuryl alcohol

Ketone / keto alcohol: acetone, 2-
Butanone, diacetone alcohol, γ-butyrolactone,
Propylene carbonate

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

Acyl nitriles: acetonitrile, propiononitrile, butyronitrile, acrylonitrile,
Methacrylonitrile, benzonitrile

Acid amide: formamide, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide,

Heterocyclic compounds: pyridine, quinoline, pyrrole, piperidine, piperazine, morpholine, 2-pyrrolidinone, 1-methyl-2-pyrrolidinone

The organic silicon compound is TEO.
The following organosilicon compounds, which are representative examples of S, TMOS, OMTCS, HMDS, SOB, DADBS, SOP and the like, are mentioned.

The tetraalkoxysilanes are as follows: tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetra-n-propoxysilane, tetra-isopropoxysilane, tetra-n-butoxysilane.

The alkylalkoxysilanes are as follows: methyltrimethoxysilane, methyltriethoxysilane, methyltrinpropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrinpropoxysilane,
Ethyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldiisopropoxysilane, methyl Vinyldimethoxysilane, methylvinyldiethoxysilane methyldimethoxysilane, methyldiethoxysilane dimethylvinylmethoxysilane, dimethylvinylethoxysilane

As polysiloxane: tetrakis (dimethylsiloxy) silane

The cyclosiloxanes are as follows: octamethylcyclotetrasiloxane (OMCTS), pentamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, trimethylcyclotrisiloxane.

The disiloxanes are as follows: hexamethyldisiloxane (HMDS), tetramethyldimethoxydisiloxane, dimethyltetramethoxydisiloxane, hexamethoxydisiloxane.

The alkylsilanes are as follows: monomethylsilane, dimethylsilane, trimethylsilane, triethylsilane, tetramethylsilane, tetraethylsilane allyltrimethylsilane hexamethyldisilane.

The silylamines are as follows: dimethyltrimethylsilylamine, diethyltrimethylsilylamine

The silane nitrogen derivatives are as follows: aminopropyltriethoxysilane, trimethylsilyl azide, trimethylsilyl cyanide

The silazanes are as follows: hexamethyldisilazane, tetramethyldisilazane octamethylcyclotetrasilazane, hexamethylcyclotrisilazane

The halogenated silanes and derivatives are as follows: trimethylchlorosilane, triethylchlorosilane, trinpropylchlorosilane, methyldichlorosilane, dimethylchlorosilane, chloromethyldimethylchlorosilane, chloromethyltrimethylsilane, chloropropylmethyldichlorosilane, chloropropyltrisilane. Methoxysilane dimethyldichlorosilane, diethyldichlorosilane, methylvinyldichlorosilane, methyltrichlorosilane,
Ethyltrichlorosilane, vinyltrichlorosilane, trifluoropropyltrichlorosilane, trifluoropropyltrimethoxysilane, trimethylsilyl iodide.

Further, as the organic silicon compound, tris (trimethylsiloxy) borane (SOB), tris (trimethylsiloxy) phosphoryl (SOP), diacetoxydi-t
ert-Butoxysilane (DADBS) or the like can also be used.

Here, the organic treatment of the base surface is spin coating (coating treatment) in which the semiconductor wafer is applied while being spun, vapor treatment in which vapor of an organic compound is blown to the semiconductor wafer, and the semiconductor wafer in a solution of the organic compound. Various treatment methods are possible, such as dipping treatment to immerse in, spray treatment to spray solution of organic compound, curtain flow coat treatment to pass semiconductor substrate through shower of organic compound, etc. It is the most preferable because it has a small amount, uniform coating can be performed, and drying can be performed at the same time. Further, in the present invention, when the underlayer surface is treated with the above organic compound, these
It is also possible to use more than one species simultaneously or sequentially.

[0038]

According to the method of manufacturing a semiconductor device according to the present invention as described above, the underlying surface is treated with the above-mentioned organic compound before forming the insulating film by the CVD method using the organic silicon compound as the source gas (hereinafter referred to as the organic substance). (Also called processing)
By performing a very simple process, it is possible to significantly reduce the dependency on the underlayer, and it is possible to form an insulating film that has excellent film filling properties and flatness as well as cracks and voids. The manufacturing apparatus will be simplified and the throughput will be improved.

Although the reason why an insulating film having a good film quality and a good filling property between the steps is formed by treating the underlying surface with an organic substance has not been clarified yet,
It can be thought of as follows.

1. SiH ₄ or TEOS-based plasma CVD oxide film, thermal CVD oxide film, or Si thermal oxide film used as a modified insulating film by ethanol treatment on the surface of the underlying insulating film is a composition similar to amorphous SiO ₂ or SiO _2. belongs to. The outermost surface of amorphous SiO ₂ is often hydrated by water in the process or in the air atmosphere, and often has a silanol type structure of Si—OH. Si-OH existing on the surface
Is an electron attracted to the Si side, which has a high electronegativity, so

[Chemical 1] It is strongly polarized in the form of and has a large dipole moment. Due to this polarization, Si-OH has the property of strongly adsorbing highly polar molecules such as water and alcohol. An important application that maximizes the Si-OH adsorption capacity by increasing the specific surface area is silica gel as a desiccant.

It is assumed that a gas organic compound is sprayed or a liquid organic compound is applied or dipped on the SiO ₂ insulating film whose surface is covered with Si—OH to act. Many organic compounds are adsorbed on the surface by the action of the polarization of Si-OH, but the strength of the adsorption depends on the polarity of the organic compound side. Non-polar substances such as cyclohexane and benzene are difficult to be adsorbed on the surface, and highly polar substances such as lower alcohol, acetonitrile and lower carboxylic acid are strongly adsorbed. Dioxane and ketones with moderate polarity are expected to be adsorbed with intermediate strength.

On the other hand, Si-OH is a Lewis that emits a proton.
It also acts as an acid and interacts with other active hydroxyl-bearing organic chemicals. A typical example is the exchange reaction of an alkoxyl group that occurs with an alcohol. For example, in the case of ethanol: C ₂ H ₅ OH, Si-OH + C ₂ H ₅ OH = Si-OC ₂ H ₅ + H ₂ O Such an esterification reaction occurs. Si formed here
The bond of -OC ₂ H ₅ is extremely strong, and Si-OC ₂ H ₅ formed on the native oxide film of Si has a life of several tens of minutes or more even in an oxidizing atmosphere at 400 ° C.

Therefore, it is considered that the gas phase or liquid phase treatment with the organic compound causes the chemical adsorption of the organic compound molecule, and the treatment with the alcohol such as ethanol also causes the esterification reaction. In any case, the silanol thus adsorbed or esterified loses its adsorbing ability and becomes an inactive surface state. To evaluate the degree of adsorption on the surface of the insulating film, the desorption temperature of the adsorbed chemical species should be used as a guide, and the tendency tends to be the same as the polarity of the adsorbed chemical species. Shows a particularly high desorption temperature.

2. O ₃ -TEOS system vapor-phase chemical reaction and vapor deposition chemical species in vapor phase In the thermal CVD reaction of O ₃ -TEOS, two intermediate chemical substances (deposition chemical species) that contribute to film formation are formed in the vapor phase. It is said to exist. One having a silanol group: HO-Si (OC ₂ H ₅ ).
₃ (A), it is considered that TEOS (Si (OC ₂ H ₅ ) ₄ ) and atomic oxygen [O] are chemically formed as follows. Note that TE
OS and O ₃ do not react directly with each other, and the initiation of the reaction is said to occur from atomic oxygen [O] generated by thermal decomposition of O ₃ .

[Chemical 2] That is, this is a reaction in which an ethoxy group bonded to Si is oxidized by an oxygen atom and decomposed to leave silanol.
In equation (1), the final oxidation products were CO ₂ and H ₂ O.
Actually, as an intermediate step, ethanol (C ₂ H ₅ OH),
Methanol (CH ₃ OH), acetaldehyde (CH ₃ CHO),
Formaldehyde (HCHO), acetic acid (CH ₃ COOH), it is believed that through the formic acid (HCOOH).

Another intermediate is a siloxane polymer:
_{(C 2 H 5 O) 3} Si-O-Si (OC 2 H 5) is ₃ (B). This is above
It is considered that the silanol intermediate (A) produced by the formula (1) is condensed to form a reaction such as (2) or (2 ').

[Chemical 3] Since the lifetime of silanol in the gas phase is generally considered to be short, the silanol intermediate (A) has a relatively short life, (2),
It is considered that the siloxane polymer (B) is easily transformed by the condensation reaction such as (2 ').

[Chemical 4]

The silanol intermediate (A) is active in the molecule
Since it has a Si-OH group, it has high activity and is easy to polymerize. In addition, it has a large intramolecular polarization and is easily adsorbed to the substrate surface. On the other hand, siloxane intermediate (B)
Has a low activity, and since it has a high boiling point and a low vapor pressure, it is highly possible that it is in a liquid state at about the film formation temperature. Since the polarization is small, it is considered that adsorption is difficult.

Therefore, in the mechanism in which the silanol intermediate (A) mainly contributes to the film formation, the adsorption of (A) onto the substrate surface occurs rapidly, and the ozone oxidation of the surplus ethoxy groups of the adsorbed molecules then occurs. Polysilanol (Si (OH)
_n , n> 1), and the silanol thus produced becomes a new adsorption site, and the film-forming species (A) in the gas phase is adsorbed again there (adsorption-decomposition mechanism). Since (A) is reactive, the lifetime of the intermediate is short, the sticking coefficient is large, and the adsorption of (A) to the easily-supplied site occurs at a high speed, which deteriorates the step coverage. Moreover, since the probability that silanol remains in the film as it is increases, the film quality and its uniformity are relatively poor, and the amount of water adsorbed on the surface tends to be large.

In contrast to this, when the siloxane polymer intermediate (B) mainly contributes to film formation, since adsorption is less likely to occur, diffusion (flow) due to interfacial tension of the polymer onto the substrate surface causes film formation. It is considered to control. The polymer that has spread to the surface undergoes silanolization and polymerization by ozone oxidation again, but since the free silanol density that appears on the surface is considered to be small, it is considered that the film-forming species (B) in the gas phase is deposited again in a fluidized state. Possible (polymerization-flow mechanism). Since the intermediate (B) has a long lifetime, the step coverage is increased and the shape is flow-like. Since the residual silanols on the surface and inside the film are reduced, the film quality is relatively improved.

Regardless of the intermediates (A) and (B), the chemical species deposited by heat or excess ozone are finally decomposed and oxidized to form a Si--O--Si network. , Close to stoichiometric amorphous SiO ₂ . However, it is considered that only one of (A) and (B) is involved in film formation, and it is considered that two chemical species are always involved in film formation. It is considered that the balance involved in the film formation of (A) and (B) changes depending on the parameters and the surface condition of the base.

3. Relationship between Surface State of Underlayer and Chemical Reaction in Gas Phase As is clear from the explanation of the above mechanism, it is understood that the shape after film formation is greatly changed depending on the balance of film forming chemical species in the gas phase. When Si-OH adsorption sites are distributed at a high density on the substrate, silanol intermediate (A) among the chemical species in the gas phase is adsorbed on the surface immediately without waiting for the polymerization reaction due to its large polarization. It is considered to be a thing. The adsorbed silanol is immediately oxidised by ozone or heat to produce silanol which can become a new adsorption site, or is adducted by another silanol intermediate (A). Film deposition by various adsorption-decomposition mechanisms continues to proceed. The deposition of the siloxane polymer (B) is also considered to proceed in parallel with that of (A), although the proportion is small, and the local fluctuation of the film quality occurs due to the mixture of the two film forming species, which causes unevenness when etching with BHF. May be the cause of. We believe that this type is the mechanism of O ₃ -TEOS film formation on the oxide film not treated with ethanol.

When the base insulating film is treated with an organic compound to crush all of the adsorbing active silanol, the silanol intermediate (A) is not adsorbed on the substrate. Therefore, the residence time in the gas phase increases and the probability of conversion to the siloxane polymer (B) increases, so that the proportion of (B) in the film formation chemical species in the gas phase increases. The siloxane polymer (B) spreads so as to cover the substrate surface with interfacial tension. This polymer has no active silanols, so once the membrane surface is covered with (B), the silanol intermediate (A)
Will not be adsorbed thereafter, and the subsequent deposition will proceed mainly by the flow of the siloxane polymer (B).

That is, the state of the substrate before the film formation can have a decisive influence on the film formation mechanism after the film formation.
The pretreatment of film formation with an organic compound is inferred from the above mechanism, and if it is a compound that is not desorbed at a film forming temperature of about 400 ° C, a complete effect can be obtained if it is adsorbed on all active adsorption sites. Any of these may be used, but acetonitrile having a high polarity and lower alcohol having an esterification action remain stable without being desorbed even at this film forming temperature, and are considered to be the most suitable ones.

However, in the earliest process in which the siloxane polymer flows due to the interfacial tension, the absolute value of the interfacial tension between the polymer and the substrate surface is likely to affect the final flow shape. That is, the wettability between the polymer and the treated substrate becomes a problem, and it is desirable to adsorb or esterify the chemical species that are well wetted by the polymer by the treatment of the organic compound in order to obtain a good flow shape. That is why the treatment with ethanol or 2-ethoxyethanol, which has the same functional groups as the polymer, actually gives favorable results.

As described above, by treating the underlayer surface on which the insulating film is to be formed with an organic compound, the underlayer dependency can be greatly alleviated, and the embedding property and the flatness are excellent. Although it has become possible to form an insulating film having an excellent film quality without cracks and voids, the inventors have succeeded in chemical treatment using an organic silicon compound as a raw material, which is performed subsequent to the treatment with the organic compound. The inventors have found that the formation of an insulating film by vapor phase growth is carried out by a low pressure chemical vapor deposition method, whereby further improvement in the embedded shape and film quality is recognized, and the present invention has been completed.

When the insulating film is formed by the chemical vapor deposition of the organic silicon compound and ozone in this way, it is considered that the effects obtained by carrying out in a reduced pressure atmosphere are as follows. (1) The mean free path of gas molecules in a gas increases as the pressure decreases. For example, the mean free path at normal pressure is 10
Whereas nm, it is about 1 μm at 10 Torr.
From this, the precursor of the film on the substrate (polymer of the reaction product of the organosilane compound such as TEOS and ozone) can penetrate deeper into the embedded hole, and the fine deep hole Can also be embedded.

(2) During film formation, ozone easily diffuses to the film surface (gas diffusion coefficient is inversely proportional to pressure),
Ozone is sufficiently supplied even on the surface of the film with fine pores, and oxygen atoms are generated by the thermal decomposition reaction on the surface, and the residual hydrogen and oxygen in the film are reduced by the reaction with the oxygen atoms. It is considered that the film quality could be modified.

Although this is based on the results of theory and experiments, it is only an inference, and it goes without saying that the technical scope of the present invention is not limited by such inference.

The specific range of the reduced pressure is from normal pressure to
As long as the pressure is reduced even slightly, the effect of the organic compound treatment under normal pressure becomes more excellent, and it becomes possible to fill even fine holes with a large aspect ratio.
It is effectively improved at 400 Torr or less, and it becomes possible to fill finer pores (diameter 0.3 μm, depth 1 μm) at 100 Torr or less. In particular, a remarkable effect is obtained in the vicinity of 20 Torr where the mean free path of molecules approaches the depth of fine pores. When the pressure is lower than 20 Torr, the embedding shape and the film quality are further improved, but on the other hand, there is a disadvantage that the film forming speed becomes slow. Therefore, the preferable depressurization range is from 2 to 2 in consideration of the film formation rate and the filling shape.
400 Torr.

In forming an insulating film by chemical vapor deposition after treatment with an organic compound, the raw material organic silicon compound is supplied to a bubbler heated to a constant temperature, and nitrogen,
Bubbling is performed using oxygen, helium, or the like as a carrier gas, and the resultant is transported to the film forming chamber. It is desirable to heat the piping after bubbling to prevent condensation. As the reaction gas, an oxygen gas containing oxygen or ozone at a concentration of 0.1 wt% or more, preferably 4 wt% or more is used. Further, it is possible to appropriately dilute with an inert gas such as nitrogen.
The flow rate ratio of the organic silicon compound, the reaction gas, and the carrier gas is not particularly limited. Insulation film formation temperature is 200-
The temperature is 500 ° C, preferably 300 to 450 ° C.

[0060]

EXAMPLES Examples and comparative examples of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the structure of an apparatus which can be commonly used as an apparatus for forming an organic silane-CVD film in Examples and Comparative Examples 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. A vacuum exhaust device (not shown) is provided on the exhaust side of the reaction chamber 1.
Is provided, and the inside of the reaction chamber 1 can be adjusted to a predetermined pressure.

(Example) Silicon substrate as shown in FIG.
A BPSG film 12 with a thickness of 6000Å is formed on 11 and an aluminum wiring 13 with a height of 1.2 μm is formed on it, and a line width of 0.4 μm,
A space width of 0.4 μm was formed, and a plasma-TEOS CVD NSG film 14 was formed on the BPSG film and aluminum wiring to a thickness of 3000 Å. The conditions for forming the plasma-TEOS CVD NSG film 14 are as follows: film forming temperature is 350 ° C., film forming pressure is 2.2 Torr, TEOS is 1.8 ml / min (value at 0 ° C., 1 atm: flow rate is The same) and oxygen gas at a rate of 4.0 l / min, and the RF power is 400 KHz, 500 W and 13.56 MHz,
A total of 1 kW of 500 W was used and the film formation time was 20 seconds. The thickness of the plasma-TEOS CVD NSG film 14 is 0.3 μm on the aluminum wiring 13, but only about 0.1 μm is formed on the side wall (aspect ratio of the hole is 1.2 ÷ (0.4 −0.
1 x 2) = about 6).

Next, the base surface of the silicon wafer was treated with ethanol. In the ethanol treatment of this example,
Place a silicon wafer on a spin coater and rotate it at 1000 rpm while adding 2 ml of ethyl alcohol at a flow rate of 100 ml / min.
After applying for 2 seconds, it was dried at 2000 rpm for 60 seconds. Next, the silicon wafer was carried into the reaction chamber, and the ozone-TEOS CVD NSG film 15 was formed to a film thickness of 10,000 Å under the following film forming conditions.

[Table 1] Film formation temperature 400 ℃ Film formation pressure 20 Torr Film formation time 436 seconds Nitrogen gas flow to gas bubbler 1.5 SLM Constant temperature bath temperature 65 ℃ Oxygen flow to ozone generator 7.5 SLM Ozone concentration 5 wt% Carrier N ₂ 18 SLM The ozone-TEOS CVD NSG film 15 thus formed fills the narrow space between the aluminum wirings 13, has good step coverage, is excellent in flatness, and has a good film quality with no voids formed. It was something that had.

(Comparative Example) As a comparative example, as shown in FIG. 3, a BPSG film 12 is formed on a silicon substrate 11, an aluminum wiring 13 is further formed thereon, and plasma-TEOSCVD is performed on the BPSG film and the aluminum wiring. The film 14 was formed to a thickness of 0.3 μm. The process up to this point is the same as in the first embodiment described above, and the aluminum wiring 13
The line width, space and height are also the same as in the first embodiment. Thereafter, the substrate was placed in the reaction chamber shown in FIG. 1 without being subjected to ethanol treatment, and an ozone-TEOS CVD NSG film 16 was formed to a thickness of 1 μm under the same film forming conditions as in Example 1.
In the comparative example, the filling of the ozone-TEOS CVD NSG film 16 between the aluminum wirings 13 was defective and a large number of voids 17 were formed, which deteriorated the device characteristics.

The present invention is not limited to the above-mentioned embodiments, but various modifications and variations are possible. For example, although the ozone-TEOS CVD NSG film is formed after the ethanol treatment in the above-described embodiment, TMOP (trime) is added to the mixed gas of ozone and TEOS supplied to the reaction chamber.
It is also possible to form an ozone-TEOS CVD PSG film or a BPSG film by adding phosphorus and boron alkoxide gas such as thoxy phosphine) and TMOB (trimethoxy borane) as a dopant. Further, not only TEOS but also the above-mentioned TMOS, OMCTS, HMDS and the like can be used as the organic silane raw material compound.

[0065]

As described above, in the method of manufacturing a semiconductor device according to the present invention, the base surface is treated with an organic substance before the insulating film is formed by the chemical vapor deposition method using the source gas of the organic compound, It is possible to form a good-quality insulating film without voids in the insulating film by a very simple process of forming the insulating film by the chemical vapor deposition method in a reduced pressure atmosphere. it can. Further, the insulating film thus formed has a low water content and an excellent moisture absorption resistance, and at the same time, there is no risk of cracks occurring in the post-treatment, and the device characteristics can be improved.

[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 semiconductor device formed by an embodiment of a method for manufacturing a semiconductor device according to the present invention.

FIG. 3 is a cross-sectional view showing a semiconductor device formed according to a comparative example.

[Explanation 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 Silicon Substrate 12 BPSG Film 13 Aluminum Wiring 14 Plasma-TEOS CVD NSG Film 15 Ozone-TEOS CVD NSG Film

Claims (3)

[Claims] 1. When forming an insulating film by chemical vapor deposition using an organic silicon compound as a raw material, the underlying surface on which the insulating film is to be formed is treated with an organic compound in advance, and thereafter the insulating film is formed. Is carried out by a low pressure chemical vapor deposition method. 2. The organic compound is an aliphatic saturated monohydric alcohol, an aliphatic unsaturated monohydric alcohol, an aromatic alcohol,
2. The semiconductor device according to claim 1, which is one or more selected from aliphatic saturated polyhydric alcohols, aldehydes, ethers, ketones, carboxylic acids, nitroalkanes, amines, acyl nitrites, acid amides, and heterocyclic compounds. Production method. 3. The reduced pressure atmosphere of the chemical vapor deposition method is 2 to 400.
The method of manufacturing a semiconductor device according to claim 1, wherein the method is Torr.