JPH06283516A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an insulating film, which is good in burying properties and at the same time, has no void, is good also in flatness and is superior in film quality, as a first interlayer insulating film. CONSTITUTION:In the case where an insulating film is formed on the surface of a silicon wafer 11, a base oxide film 12 is first formed, then, after the surface of this film 12 is treated with an organic compound, the insulating film 14 is formed by a chemical vapor deposition method using one kind of a compound or two kinds or more of compounds selected from among an organic silicon compound and each organic compound containing B, P, Ge or As as a raw material or raw materials. Then, the film 14 is reflowed at a temperature of 400 deg.C or higher. By treating the surface of the film 12 with the organic compound in such a way, the insulating film, which is good in burying properties, has no void and is good in film quality, can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a first insulating film formed on a gate electrode of a field effect transistor.

[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 gate width of the MOSFET also decreases, which increases the aspect ratio of the step near the gate electrode.
It is becoming difficult to embed the first insulating film formed on them between the steps.

In order to form a good quality insulating film on a substrate having a high aspect ratio as described above, TEOS (tetraethoxysilane) which is one of organic silanes and ozone are used as a source gas by a normal pressure CVD method to form boron ( TEOS-O ₃ BPSG (borophosphosilicate) doped with B) and phosphorus (P)
It is known to form a glass) film.

The atmospheric pressure CVD method using such a mixed gas of ozone-organosilane is described in, for example, JP-A-61-77695 and "Electrochemistry" 56, No. 7 (1988), pages 527 to 532. Have been described. In addition, TEOS (tetraetho
xysilane), TMOS (tetramethoxysilane), OMCTS (octameth
ylcyclotetrasiloxane), HMDS (hexamethyldisiloxane)
Are known.

[0005]

[Problems to be Solved by the Invention] However, the above TEOS-O
₃ Reflow has been used as a planarization method using BPSG film, but the flatness after reflow is not sufficient and high temperature is required during reflow. Therefore, there is a demand for a technique for forming an insulating film having a high aspect ratio at a lower temperature and having excellent filling characteristics between steps. Needless to say, since it is used as an insulating film, it is necessary to have excellent film quality such as generation of voids and degassing.

Since the film quality of the TEOS-O ₃ BPSG film varies depending on the material of the base and the film forming conditions, it is difficult to stably form a film having a good film quality. In order to solve such a problem, it has been proposed to perform plasma treatment on the underlying surface before forming the BPSG film (Kubo et al., Proc. Of the 40th Japan Society of Applied Physics P.579, 16P-ZQ- 6, September 1992). However, this solution has the disadvantage that the underlying substrate is damaged by the plasma treatment. Particularly, when the vicinity of the gate electrode is exposed to plasma, electrical damage given to the transistor is serious, and there is a drawback that the transistor characteristics are adversely affected.

The object of the present invention is to solve the above-mentioned drawbacks of the conventional insulating film forming method, to be particularly effective for use as an insulating film for submicron devices, and to be excellent in embedding between steps having a high aspect ratio. Therefore, it is possible to form an insulating film which has less moisture in the film, less voids, and no damage to the base at a low temperature, and to obtain an insulating film having excellent flatness. It is intended to provide a manufacturing method.

[0008]

In the method of manufacturing a semiconductor device according to the present invention, when forming an insulating film of a semiconductor device, a base oxide film is first formed, and then the surface of the base oxide film is treated with an organic compound. After that, with an organic silicon compound,
The invention is characterized in that an insulating film is formed by chemical vapor deposition using one or more kinds selected from organic compounds containing B, P, Ge and As as a raw material, and then reflowed at a temperature of 400 ° C. or higher. To do.

In forming an insulating film of a semiconductor device, a base oxide film is first formed, then the surface of the base oxide film is treated with an organic compound, and then an organic compound containing B, P, Ge and As is used. An insulating film is formed by chemical vapor deposition using one or more selected materials as raw materials, and then
It is characterized by diffusing and reflowing at a temperature of 400 ° C or higher.

In this case, the underlying oxide film is made of silane as a raw material such as LTO (low temperature oxide) and HTO (high te).
It is preferable that the NSG is made of mperature oxide) or TEOS as a raw material, and it is also preferable to further perform a flattening treatment after the reflow.

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

As the organic compound treatment method, spin coating treatment (coating treatment) for applying the semiconductor wafer while spinning it, vapor treatment for spraying the vapor of the organic compound onto the semiconductor wafer, and immersing the semiconductor wafer in the solution of the organic compound. Various treatment methods are possible such as dipping treatment, spray treatment for spraying a solution of organic compound, curtain flow coating treatment for passing a semiconductor substrate through a shower of organic compound, and spin coating method consumes less organic compound, It is most suitable because it can be applied uniformly and can be dried at the same time.

[0026]

According to the method of manufacturing a semiconductor device of the present invention as described above, a base oxide film is first formed, and after the surface of the base oxide film is subjected to simple processing such as organic compound treatment, B, P By forming the insulating film by the CVD method using one or more kinds selected from organic compounds including Si, Ge and As as a raw material, the dependency of the insulating film on the underlayer can be eliminated and the filling property between the steps can be improved. It is possible to form an insulating film which is particularly excellent, has a small amount of water in the film, has few voids and cracks, and has a good film quality. Moreover, since the element is not damaged during the formation of the insulating film, the reliability of the semiconductor device can be improved. Further, after forming such an insulating film, by reflowing at 400 ° C. or more, the surface can be smoothed, the steps can be further alleviated, and the weak film quality portion (keyhole) can be completely removed.

The reason why an insulating film having a good film quality and a good burying property between the steps can be formed by treating the underlying surface with an organic compound has not been clarified yet, but is considered as follows. be able to. The cause of improving the embedding property and film quality of the insulating film by treating the thermal oxide film with ethanol is considered below with respect to TEOS.

[1. Deformation of the underlying insulating film surface by ethanol treatment] SiH ₄ or TEOS-based plasma CVD oxide film or thermal CVD oxide film used as an insulating film, and Si thermal oxide film are all close to amorphous SiO ₂ or SiO ₂ . It is of composition. 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. Since Si-OH existing on the surface has electrons attracted to the Si side, which has a high electronegativity,

[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.

When the above-described organic compound treatment is applied to the insulating film whose surface has a Si—OH type structure in this way,
The following behaviors are estimated to occur. Many organic compounds are adsorbed on the surface by the action of Si-OH polarization. The strength of adsorption depends on the polarity of the organic compound side, and non-polar substances such as cyclohexane and benzene are hard to be adsorbed on the surface, lower alcohols, acetonitrile,
It is expected that highly polar substances such as lower carboxylic acids will be strongly adsorbed, and that dioxane and ketones having moderate polarity will be adsorbed with intermediate strength.

On the other hand, Si-OH also functions as a Lewis acid that releases a proton, and interacts with other organic chemical substances having an active hydroxyl group. A typical example is the exchange reaction of an alkoxyl group with an alcohol,
Such as ethanol: C ₂ H ₅ OH between at _{Si-OH + C 2 H 5} OH = Si-OC 2 H 5 + H 2 esterification reactions such as O 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.

As described above, it is considered that the gas phase or liquid phase treatment with an organic compound causes chemical adsorption of the molecule of the organic compound, and the treatment with an alcohol such as ethanol also causes an esterification reaction. To be In any case, the silanol thus adsorbed or esterified loses its adsorbing ability and becomes an inactive surface state.

[2. O ₃ -TEOS vapor phase chemical reaction and vapor deposition chemical species in vapor phase] By the way, in the thermal CVD reaction of O ₃ -TEOS, two intermediate chemical substances (film deposition chemical species) that contribute to film formation are vapor phase. It is said to exist inside. One having a silanol group: HO-Si (OC ₂ H ₅ ) ₃ (A), which has the following TEOS (Si
It is considered to be formed by a chemical reaction between (OC ₂ H ₅ ) ₄ ) and atomic oxygen [O]. TEOS 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 decomposed by being oxidized by an oxygen atom to leave silanol. In equation (1), the final oxidation products are CO ₂ and H ₂ O.
However, as an intermediate step, in practice, ethanol (C ₂ H ₅ OH), methanol (CH ₃ OH), acetaldehyde (CH ₃ CHO), formaldehyde (HCHO), acetic acid (CH ₃ C).
OOH) and 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 above silanol intermediate (A) has high activity because it has an active Si-OH group in the molecule, has the property of being easily polymerized, and has a large polarization in the molecule.
It is easily adsorbed to the substrate surface. On the other hand, the siloxane intermediate (B) has a low activity, and since it has a high boiling point and a low vapor pressure, it is highly likely that it is in a liquid state at about the film forming temperature. Since the polarization is small, it is considered that adsorption is difficult.

Therefore, in the thermal CVD reaction of O ₃ -TEOS, when the silanol intermediate (A) mainly contributes to the film formation, the adsorption of (A) onto the substrate surface occurs promptly, and then the adsorption occurs. Polysilanol (Si (OH) _n , n> 1) is formed by ozone oxidation of surplus ethoxy groups in the molecule, and the generated silanol becomes a new adsorption site, where the film-forming species (A) in the gas phase is adsorbed again. It is considered that the process proceeds as follows (adsorption-decomposition mechanism). Since the reaction of (A) is active, the lifetime of the intermediate is short, the sticking coefficient is large, the adsorption of (A) to the easily supplied site occurs rapidly, and the step coverage deteriorates. Become. Moreover, since the probability that the silanol remains in the film as it is increases, the quality and uniformity of the obtained oxide film 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 lifetime of this intermediate (B) is long, the step coverage is improved, and the intermediate has a flow-like shape. 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 . It should be noted that only one of (A) and (B) is not involved in film formation, and it is considered that two chemical species are always involved, and film formation such as ozone concentration and film formation temperature. 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 above description of the mechanism, the shape after film formation is greatly changed depending on the balance of film forming chemical species in the gas phase. Here, in the conventional method in which the underlayer surface is not treated with an organic compound, the Si-OH adsorption sites are distributed at a high density on the substrate, so during the O ₃ -TEOS film formation, It is considered that among the chemical species, the silanol intermediate (A) is immediately adsorbed on the surface without waiting for the polymerization reaction due to its large polarization. The adsorbed silanol is immediately oxidized by ozone or heat to generate silanol which can become a new adsorption site, or is added by another silanol intermediate (A), and thereafter (A) is dominant. Film deposition by various adsorption-decomposition mechanisms continues to proceed. Also, the deposition by the siloxane polymer (B) is thought to proceed in parallel with (A), although the proportion is small, and a local fluctuation of the film quality occurs due to the mixture of two film-forming species, which is etched by BHF. It is thought that this may be the cause of unevenness in time.

[0040] In contrast, according to the present invention, a base insulating film is treated with an organic compound, if crushed all adsorbed active silanols underlying surface, silanol intermediates in the formation of the O ₃ -TEOS ( A) is no longer 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. Moreover, since this polymer does not have active silanol, once the film surface is covered with (B), the silanol intermediate (A) is not adsorbed thereafter, and the flow of the siloxane polymer (B) in all subsequent depositions. It is considered that the oxide film having good embedding property, flatness, and film quality is formed as a result of progressing mainly.

As described above, the state of the substrate before the film formation can have a decisive effect on the film formation mechanism after the film formation. The pretreatment of film formation with an organic compound according to the present invention is presumed from the above mechanism, and it is possible to obtain a complete effect if all the organic compounds are adsorbed on the active adsorption sites on the underlying surface, and the pretreatment at a temperature of about 400 ° C. Any organic compound may be used as long as it is not desorbed at the film temperature, and particularly, acetonitrile having a high polarity or lower alcohol having an esterification action is not desorbed at this film forming temperature and remains stable. And is considered to be the most appropriate one.

In the earliest stage of film formation, 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 may affect the final flow shape. It is highly likely. That is, the wettability between the polymer and the organic compound-treated substrate surface is important,
As the organic compound species, it is desirable to adsorb or esterify a chemical species that wets the polymer well by the treatment in order to obtain a good flow shape. It is speculated that this is the reason why the treatment with ethanol or 2-ethoxyethanol having the same functional group as that of the polymer actually gives preferable results.

In the above description, the case of the O ₃ -TEOS CVD insulating film has been described, but in addition to TEOS, B, P, Ge and As.
It is considered that the same mechanism is used in the present invention in which an organic compound containing B is mixed, or only an organic compound containing B, P, Ge and As is used. This is based on the results of theory and experiment, but it is only inference,
Needless to say, the technical scope of the present invention is not limited by such inference.

Examples of the underlying oxide film in the present invention include a thermal oxide film and LTO, HTO made from silane as a raw material or NSG made from TEOS as a raw material. When a thermal oxide film is used as the base, after treating with an organic compound, an organic silicon compound such as TEOS and one or more selected from organic compounds containing B, P, Ge and As are used as raw materials. If the insulating film is formed by chemical vapor deposition used as, for example, atmospheric pressure thermal CVD with ozone, the step can be completely filled.

Further, LTO made of silane as a base material
, HTO or TEOS is used as the starting material, it is treated with an organic compound, and then one or two selected from the organic compounds containing B, P, Ge and As, which are highly effective in lowering the pour point. If an insulating film is formed by chemical vapor deposition using seeds or more as raw materials, for example, atmospheric pressure thermal CVD with ozone,
Even better flatness can be obtained.

Examples of the organic silicon compound include TEOS and TMO
The following organosilicon compounds, which are representative examples of S, OMTCS, HMDS, SOB, DADBS, SOP, etc., can be mentioned.

The tetraalkoxysilanes are as follows: tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetra-n-propoxysilane, tetra-isopropoxy-silane, tetra-n-butoxy-silane.

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 following are alkylsilanes: 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, tri-n-propylchlorosilane, 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.

The organic compounds containing B, P, Ge and As are as follows. Compounds containing _{B: BH 3, B (CH} 3) 3, BH 2 CH 3, B (N (CH 3) 3)
_{3, B (OCH 3) 3} , B (OC 2 H 5) 3 , etc. Compounds containing _{P: PH 3, PO (OCH} 3) 3, (CH 3) 3 P, (CH 3) 3
Compounds containing PO or the like _{Ge: GeH 4, Ge (CH} 3) 4, Ge (OCH 3) 4, Ge (OC 2
H ₅ ) _4, etc., compounds containing As: AsH ₃ , As (CH ₃ ) ₃ , AsO (OCH ₃ ) ₃ , AsO (OC
₂ H ₅ ) _3, etc. Also, these compounds can be mixed and used.

The formation of the insulating film by chemical vapor deposition, which is performed after the organic compound treatment, is at atmospheric pressure or close to atmospheric pressure (up to 400 Torr).
r) Low pressure CVD method is preferred. The organic silicon compound as a raw material is supplied to a bubbler heated to a constant temperature, and nitrogen, oxygen, helium, etc. are bubbled as a carrier gas,
Transport to deposition chamber. It is desirable to heat the piping after bubbling to prevent condensation. Further, as the reaction gas, an oxygen gas containing oxygen or ozone in 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 deposition temperature is 200-700 ℃
Is.

After forming the insulating film, the flatness can be further improved by reflowing at a temperature equal to or higher than the softening point of the insulating film. The specific reflow temperature is generally not lower than the film forming temperature, and is preferably 700 to 900 ° C.

In the present invention, it is also possible to carry out the flattening process after the reflow process, aiming for complete flattening. As this flattening treatment, there is an example in which a resist or SOG film is formed and then etched back together with the doped silicate glass.

[0062]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shown in FIG. 1 shows a part of a semiconductor device manufactured by the method according to the present invention. Prepare an 8-inch silicon wafer, deposit 1 μm polysilicon on this substrate, and then
By etching, pattern width 0.5 μm, height
A step of polysilicon 12 having a size of 1.0 μm and a space width of 0.5 μm was formed. The aspect ratio became about 2. After cleaning this substrate with pure water, dry oxidation is performed to form a thermal oxide film 13 with a thickness of 50 nm.
Was formed. Then, the substrate was attached to a spin coater as an organic compound treatment, 3 ml of methanol or ethanol was added dropwise within 1 second while rotating at 3000 rpm, and the rotation was kept for 3 minutes to dry. After that, this substrate was transferred into a film forming chamber, and an insulating film 14 was formed to a thickness of about 600 nm by using atmospheric pressure thermal CVD method using various source gases shown in Table 1.
At the time of this film formation, the raw material gas was charged into a bubbler kept at 65 ° C., bubbled with about 2 slm of nitrogen gas and conveyed, and oxygen gas containing 5% ozone was used as a reaction gas. The temperature was 400 ° C., the deposition pressure was normal pressure, and the deposition time was 10 minutes. After the film formation, the film was heated at 700 ° C. for 20 minutes and reflowed. Table 1 also shows the results of examining the film composition and the flatness of the insulating film 14 thus obtained.
In the table, the embedding property was evaluated by a cross-section electron micrograph, and the flatness was obtained by measuring the taper angle θ shown in FIG. 2 from the observation of the cross-section electron micrograph.

[0063]

[Table 1]

As is clear from Table 1, in the comparative example in which the surface of the underlying oxide film is not treated with ethanol or methanol, the embedding property is not perfect and the film quality is poor.
In the example, the step was completely buried and the film quality was sufficiently good.

(Embodiment 2) As shown in FIG. 3, an 8-inch silicon wafer is prepared, 1 μm of polysilicon is formed on this substrate, and then etching is performed to obtain a pattern width of 0.5 μm. Height 1.0 μm, space width
A step of 0.5 μm of polysilicon 12 was formed. Next, when a silicon oxide film 15 (LTO) was formed by atmospheric pressure thermal CVD of monosilane and nitrous oxide, the step was 0.9 μ in depth.
m, space width was 0.3 μm, and the aspect ratio was about 3. Next, the substrate was attached to a spin coater as an organic compound treatment, and 3 ml of methanol or ethanol was added dropwise within 1 second while rotating at 3000 rpm, and the rotation was kept for 1 minute to dry. After that, this substrate was transported into a film forming chamber, and an insulating film 14 was formed to a thickness of about 600 nm by using atmospheric pressure thermal CVD method using various raw material gases shown in Table 2.
The film forming conditions at this time are the same as in Example 1. After film formation,
Reflow was performed by heating at 700 ° C for 10 minutes. Table 2 also shows the results of examining the film composition and the flatness of the insulating film 14 thus obtained.

[0066]

[Table 2]

As is clear from Table 2, in the comparative example in which the surface of the underlying oxide film was not treated with ethanol or methanol, the filling property was not perfect and the film quality was poor.
In the example, the step was completely buried and the film quality was sufficiently good.

[0068]

As described above, in the method of manufacturing a semiconductor device according to the present invention, one or more selected from organic compounds containing B, P, Ge and As, or in addition to them, organic silicon. Before the insulating film is formed by the chemical vapor deposition method using a compound as a source gas, the embedding property between the steps having a high aspect ratio is improved by a very simple process of treating the underlying surface of the oxide film with an organic compound. It is possible to form a good quality insulating film having no voids in the insulating film. In addition, the insulating film thus formed has a small amount of water and has excellent moisture absorption resistance, and there is no risk of cracks occurring in the post-treatment, so that the device characteristics can be improved. Further, since the treatment with ethanol does not damage the base, there is no fear of deteriorating the electrical characteristics of the semiconductor device. Further, it is also excellent in flatness.

[Brief description of drawings]

FIG. 1 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. 2 is an explanatory diagram of a flatness evaluation method.

FIG. 3 is a sectional view showing a semiconductor device formed by another embodiment of the method for manufacturing a semiconductor device according to the present invention.

[Explanation of symbols]

 11 Silicon substrate 12 Thermal oxide film 13 Polysilicon 14 Insulating film 15 LTO film

Claims (4)

[Claims] 1. When forming an insulating film of a semiconductor device, a base oxide film is first formed, and then the surface of the base oxide film is treated with an organic compound, and then an organic silicon compound is formed.
The invention is characterized in that an insulating film is formed by chemical vapor deposition using one or more kinds selected from organic compounds containing B, P, Ge and As as a raw material, and then reflowed at a temperature of 400 ° C. or higher. Of manufacturing a semiconductor device. 2. When forming an insulating film of a semiconductor device, a base oxide film is first formed, and then the surface of the base oxide film is treated with an organic compound, and then an organic compound containing B, P, Ge and As is used. An insulating film is formed by chemical vapor deposition using one or more selected materials as raw materials, and then 40
A method of manufacturing a semiconductor device, which comprises diffusing and reflowing at a temperature of 0 ° C. or higher. 3. The underlying oxide film is LTO made of silane as a raw material.
3. The method for manufacturing a semiconductor device according to claim 1, which is NSG made of HTO or TEOS as a raw material. 4. The method of manufacturing a semiconductor device according to claim 1, wherein after the reflow, a planarization process is further performed.