Coating processes – Coating by vapor – gas – or smoke – Mixture of vapors or gases utilized
Patent
1997-12-05
1999-08-10
King, Roy V.
Coating processes
Coating by vapor, gas, or smoke
Mixture of vapors or gases utilized
4272552, 4272551, 427 99, 427578, 438786, C23C 1630, H01L 21316
Patent
active
059356499
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for manufacturing semiconductor devices and, more particularly, to a method for forming a layer insulation film utilizing a silicon oxide film.
BACKGROUND ART
For example, conventional techniques in this field include that disclosed in an article "A Study on the Structure of PE-CVD SiOF Films" by Takashi Usami et al. on Shingaku Giho SDM 94-146 (November, 1994).
Silicon oxide films (SiO2) utilizing plasma enhanced chemical vapor deposition (PE-CVD) have been commonly used as insulation films of semiconductor devices. However, a trend toward finer and more highly integrated devices has resulted in increased capacitance between lines which has an influence on the driving power of the devices.
This has resulted in an increased need for insulation films having a lower relative dielectric constant, and fluoridated (F) silicon oxide films (SiOF) have come to attention as one of such materials having a low relative dielectric constant. As disclosed in the above-mentioned article, SiOF can be formed by mixing tetraethyl orthosilicate (TEOS), oxygen (O2), and an etching gas including fluorine (F) (e.g., C.sub.2 F.sub.6, CF.sub.4, NF.sub.3, HF, etc.) in a reaction chamber under plasma discharge.
However, an insulation film made of SiOF formed using the above-described conventional method has high absorptivity of moisture and absorbs a large amount of moisture thereinto.
(1) it can cause corrosion of a metal line which is a factor of a semiconductor device; and
(2) it reduces the lifetime of a transistor which forms a factor of a semiconductor device, and this has made it difficult to manufacture semiconductor devices of high reliability.
It is an object of the present invention to eliminate the above-described problems and to provide highly reliable semiconductor devices by reducing the absorptivity of moisture of insulation films made of SiOF.
DISCLOSURE OF THE INVENTION
In order to achieve the above-described object, according to the present invention:
(1) in a method for manufacturing a semiconductor device utilizing a silicon oxide film including fluorine as a layer insulation film of a semiconductor integrated circuit, an inert gas is introduced in addition to source gases during the formation of said silicon oxide film including fluorine, which, as a result, makes it possible to improve the efficiency of dissociation of the material gas, thereby allowing the formation of a more uniform film;
(2) in a method for manufacturing a semiconductor device according to the above (1), said inert gas is at least one gas selected from helium and argon, which results in an increased compressive stress of the SiOF film to allow the film to be denser; and
(3) in a method for manufacturing a semiconductor device according to the above (1), said source gases include tetraethyl orthosilicate (TEOS), hexafluorocarbon (C.sub.2 F.sub.6), and oxygen (O.sub.2) used as a silicon source, a fluorine source, and an oxidizer, respectively, and the inert gas is used in an amount which is seven times or more of that of the silicon source gas, which improves the absorptivity of moisture of the film thus formed, and such an effect is further enhanced by increasing the amount of helium supplied.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a PE-CVD apparatus used for forming a SiOF layer insulation film to indicate an embodiment of the present invention.
FIG. 2 is a sectional view showing the formation of a SiOF layer insulation film to indicate an embodiment of the present invention.
FIG. 3 illustrates a compressive stress of a SiOF film relative to the amounts of helium and argon gas supplied to indicate an embodiment of the present invention.
FIG. 4 illustrates an infrared absorption spectrum of a SiOF film with 2000 .ANG. thick measured after moistening for three hours under a condition that a temperature is 80.degree. C. and humidity is 80% under the atmospheric pressure to indicate an embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTIO
REFERENCES:
patent: 5413967 (1995-05-01), Matsuda et al.
patent: 5563105 (1996-10-01), Dobuzinsky et al.
"Formation technology of Low Dielectric Constant SiOF Film Using C2F6 Additional PECVD System", Takashi Usami, et al. pp. 68-73 No other data|.
Extended Abstract (The 54th Autumn Meeting, 1996); The Japan Society of Applied Physics, JSAP Catalog No.: AP931122-02, p. 687, S. Mizuno, et al. No month data.
Japanese Journal of Applied Physics Jan. 1994, vol. 33, No. 1B, Issn 0021-4922, p. 408-p. 412, Takashi Usami, et al.
"A Study of Film Structure in PECVD SiOF", Takashi Usami, et al., VLSI R&D Center, Oki Electric Industry Co., Ltd., Technical Report of IEICE. SDM94-146(1994-11), pp. 43-48.
A Study of Film Structure in PECVD SiOF(II), Satoshi Koizumi, et al., VLSI R&D Center, Oki Electric Industry Co., Ltd., Technical Report of IEICE. SDM95-180(1995-12), pp. 41-45.
Fukuda Hideaki
Koizumi Satoshi
Mori Yukihiro
Yoshimaru Masaki
ASM Japan K.K.
King Roy V.
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