JPH08321499A - Silicon compound film and forming method thereof - Google Patents

Abstract

PURPOSE: To obtain a material enabling formation of a film which is not oxidized or decomposed in a heat treatment process used for a semiconductor manufacturing process, of which the moisture absorbing properties are small and which is not oxidized by an oxygen plasma treatment, and enabling realization of a dielectric constant of a specific value or below. CONSTITUTION: A silicon compound film which is constituted of a silicon compound containing a fluorocarbon group and has a dielectric constant of 3.0 or below is obtained by conducting plasma CVD in an atmosphere containing the gas of a fluorine-containing organic silane compound which is derived from an organic silane compound expressed by a general formula R<1> x SiR<2> 4-x (1) [where R<1> denotes 1-6C alkyl, R<2> H or 1-3C alkoxyl and (x) an integer of 1-3] and fluorine or a fluorine compound.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicon compound film and a method for manufacturing the same. The film obtained by the method for forming a silicon compound film of the present invention has a low dielectric constant and low hygroscopicity. Therefore, an integrated circuit formed by using this silicon compound film can provide a high speed device with less wiring delay. In addition, this silicon compound film is S
Since it is composed of an i-perfluoro group, it is a material that can withstand the enzyme plasma treatment used in the semiconductor manufacturing process, and retains a low dielectric constant throughout the manufacturing process.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor integrated circuits is improved,
As the surface level difference in device formation increases, fine wiring
In order to prevent increase in wiring resistance due to
In essence On the other hand, the wiring delay (t) is the wiring resistance
It is affected by (R) and the capacitance (C) between wirings, and is represented by t = kCR (k is constant). Therefore,
As a method to reduce wiring delay, wiring resistance is
There are two ways to reduce the dielectric constant of the insulating film:
Be done. The present invention reduces wiring delay by lowering the dielectric constant of the insulating film.
It is a way to reduce it. Conventionally, as an insulating material,
SiO by chemical vapor deposition (CVD) ₂System material is used
It has been used. SiO having the lowest dielectric constant among CVD materials₂
And its dielectric constant was about 4.0. Low dielectric constant CVD film
Recently, SiOF-based materials have been widely studied.
Has a dielectric constant of 3.0 to 3.5.
There is the problem of rising prices. Also, low dielectric constant materials
Fluorocarbon-based polymers that have long been known as
Has a thermal decomposition temperature of 400 ° C or lower,
Thermal decomposition occurs at temperatures above 400 ° C used in process
Therefore, practical application is difficult.

[0003]

As described above, a high speed device using a low dielectric constant insulating film has been studied. However, since the conventional CVD film uses a SiO ₂ based material, it is difficult to reduce the dielectric constant in the conventional material system. In addition, S formed by using a tetrafunctional silane source and a fluorine-based gas
The iOF film has a problem that its dielectric constant decreases from 4.0 to 3.0 to 3.5 as compared with the conventional material, but the dielectric constant increases due to moisture absorption.

An object of the present invention is to solve these problems, and to form a film that does not undergo oxidation or decomposition in the heat treatment process used in the semiconductor manufacturing process and is not oxidized by oxygen plasma treatment. Is possible and 3.0
It is to provide a material capable of realizing the following dielectric constant. Another object of the present invention is to provide a film having low hygroscopicity and preventing hydrolysis due to moisture absorption, and a method for producing the film.

[0005]

According to the present invention, in order to solve the above-mentioned problems, the following general formula (1), R ¹ _x SiR ² _4-x (1) [wherein R ¹ is a carbon number 1 to 6 represents an alkyl group, preferably an alkyl group having 1 to 3 carbon atoms, R ² represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms, and x is an integer of 1 to 3] A fluorocarbon group-containing silicon compound obtained by performing plasma CVD in an atmosphere containing a fluorine-containing organic silane compound gas derived from an organic silane compound and fluorine or a fluorine compound. A silicon compound film having a dielectric constant is provided.

That is, this silicon-containing compound film is subjected to plasma CVD in an atmosphere containing a fluorine-containing organosilane compound gas derived from the organosilane compound represented by the general formula (1) and fluorine or a fluorine compound. It can be obtained by doing. For example, a fluorocarbon group-containing silicon oxide compound film is obtained by performing plasma CVD in an atmosphere containing the above-mentioned fluorine-containing organosilane compound gas and oxygen gas. Similarly, if plasma CVD is performed in an atmosphere containing the above-mentioned fluorine-containing organosilane compound gas and nitrogen gas, a fluorocarbon group-containing silicon nitride compound film is obtained, and the fluorine-containing organosilane compound gas and nitric oxide gas are obtained. Plasma CVD in an atmosphere containing
By carrying out, a fluorocarbon group-containing silicon nitride oxide compound film is obtained.

In the present invention, the gas generation of the fluorine-containing organosilane compound and the plasma CVD may be performed in the same chamber or may be performed in different chambers. When the gas containing the fluorine-containing organosilane compound and the plasma CVD are performed in separate chambers, the gas containing the fluorine-containing organosilane compound is generated in the first chamber, and then this gas is introduced into the second chamber. ,
Plasma CVD can be performed in this second chamber.

The gas of the fluorine-containing organosilane compound is obtained by reacting the organosilane compound represented by the general formula (1) with fluorine or a fluorine compound. Here, the fluorine is a fluorine gas, and the fluorine compound is preferably a gas of a nitrogen fluoride compound such as NF ₃ or a gas of a fluorocarbon compound such as C ₂ F ₆ . The present invention also provides an organosilane compound represented by the following general formula (2), R ³ ₃ SiCF ₃ (2) [wherein R ³ represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms]. Provided is a silicon compound film made of a fluorocarbon group-containing silicon compound obtained by performing plasma CVD in an atmosphere containing oxygen gas.

This silicon compound film can be obtained by performing plasma CVD in an atmosphere containing the organosilane compound represented by the general formula (2) and oxygen gas. In this method, fluorine gas may be added to the atmosphere, and the fluorine gas is preferably fluorocarbon, F ₂ or NF ₃ gas.

[0010]

The silicon compound film according to the present invention is made of a fluorocarbon group-containing silicon compound having a SiCF _x bond and can form a low dielectric constant film. In addition, the formed low dielectric constant film is less susceptible to thermal decomposition and oxidation in the semiconductor manufacturing process. Furthermore, since the hygroscopicity is low and the change in the dielectric constant is unlikely to occur, the low dielectric constant can be maintained. Further, the stress can be controlled by changing the flow rate ratio of the introduced gas. Therefore, by using the silicon compound film of the present invention as an insulating film or a moisture resistant protective film, a highly reliable semiconductor device can be obtained and a high speed device with less wiring delay can be realized.

[0011]

EXAMPLES The present invention will be further described with reference to the following examples. Example 1 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate.

POWER: High frequency (13.56 MHz) / 80 W Low frequency (250 KHz) / 90 W Pressure: 5 Torr Substrate temperature: 400 ° C. Electrode distance: 250 mils Gas partial pressure: Methyltriethoxysilane: C ₂ F ₆ : O ₂
= 480: 700: 350 sccm (however, methyltriethoxysilane is introduced into the chamber by He bubbling, which is the flow rate of He) Film formation rate: 500 Å / min The infrared absorption spectrum of the formed thin film is shown in FIG. Shown in. FIG.
From this, it is understood that this thin film has a Si—CF bond.
An electrode was formed on this film and the dielectric constant was measured. Ε =
It was confirmed that the film was 2.5 (frequency 1 MHz).

Next, under the same conditions as above, the wiring thickness 80
When this insulating film was formed on a substrate having an aluminum wiring of 00 Å and a minimum line width of 0.5 μm, heat-treated at 500 ° C., and further subjected to oxygen plasma treatment, film reduction and crack generation were not observed. In addition, as a result of re-measurement of the dielectric constant after leaving it in the atmosphere for one week, no change in the dielectric constant was observed. It was also confirmed by the measurement of the adsorbed water by the temperature programmed desorption gas analysis that the adsorbed water amount was equivalent to that of the CVD-SiN film.

Example 2 A thin film was formed on a substrate on which five ring oscillators were formed under the same conditions as in Example 1, and through holes were formed so that the ring oscillators were connected in series, and the second layer was formed. a substrate formed to interconnect, were prepared substrate using TEOS-SiO ₂ film formed under the same conditions as in example 1 except for changing the gas partial pressure of the insulating film as a comparative material.

As a result of comparing the wiring delays of the respective substrates, about 25% is obtained in the substrate using the insulating film according to the present invention.
It was found that the wiring delay can be shortened. Example 3 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate.

POWER: High frequency (13.56 MHz) / 80 W Low frequency (250 KHz) / 90 W Pressure: 5 Torr Substrate temperature: 400 ° C. Electrode distance: 250 mils Gas partial pressure: Methylsilane: C ₂ F ₆ : O ₂ = 20: 70
0: 350 sccm Film formation rate: 500 Å / min The infrared absorption spectrum of the formed thin film is similar to that shown in FIG. 1, which indicates that this thin film has a Si—CF bond. An electrode was formed on this film and the dielectric constant was measured.
It was confirmed that the film was 2.5 (frequency 1 MHz).

Next, under the same conditions as above, the wiring thickness 80
When this insulating film was formed on a substrate having an aluminum wiring of 00 Å and a minimum line width of 0.5 μm, heat-treated at 500 ° C., and further subjected to oxygen plasma treatment, film reduction and crack generation were not observed. In addition, as a result of re-measurement of the dielectric constant after leaving it in the atmosphere for one week, no change in the dielectric constant was observed. It was also confirmed by the measurement of the adsorbed water by the temperature programmed desorption gas analysis that the adsorbed water amount was equivalent to that of the CVD-SiN film.

Comparative Example 1 Using a parallel plate type plasma CVD apparatus, S
A thin film having a thickness of about 0.5 μm was formed on the i flat plate. POWER: High frequency (13.56MHz) / 80W Low frequency (250KHz) / 90W Pressure: 5Torr Substrate temperature: 400 ° C Distance between electrodes: 250mils Gas partial pressure: Tetraethoxysilane: C ₂ F ₆ : O ₂ = 4
80: 700: 350sccm (however, tetraethoxysilane is introduced into the chamber by He bubbling, which is the flow rate of He) Film formation rate: 500Å / min. An electrode is formed on this film and the dielectric constant is measured. Result ε =
It was confirmed that the film was 3.2 (frequency 1 MHz).

Next, under the same conditions as above, the wiring thickness 800
When this insulating film was formed on a substrate on which aluminum wiring having a minimum line width of 0 .mu.m and a width of 0.5 .mu.m was formed, the insulating film was heat-treated at 500.degree. However, when the permittivity was measured again after being left in the atmosphere for 1 week, the permittivity increased to ε = 5.4 (frequency 1 MHz). It was confirmed by the thermal desorption gas analysis that the amount of adsorbed water increased by about one digit in the measurement of adsorbed water.

Example 4 Using a parallel plate type plasma CVD apparatus, a reaction was first carried out under the following conditions. POWER: High frequency (13.56MHz) / 80W Low frequency (250KHz) / 90W Pressure: 5 Torr Temperature: 400 ° C Gas partial pressure: Methyltriethoxysilane: NF ₃ = 48
0: 700 sccm (however, methyltriethoxysilane is introduced into the chamber by He bubbling, and the flow rate is He). Then, the generated reaction gas is transferred to an apparatus having the same configuration as above, and in this apparatus, A thin film having a thickness of about 0.5 μm was formed on a Si flat plate under the following conditions.

POWER: High frequency (13.56 MHz) / 80 W Low frequency (250 KHz) / 90 W Pressure: 5 Torr Substrate temperature: 400 ° C. Electrode distance: 250 mils Gas partial pressure: The above reaction gas: O ₂ = 350: 350 sccm Film formation rate : 3000Å / min As a result, a thin film almost equivalent to that of Example 1 was obtained.

Example 5 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate. Applied power: 13.56MHz / 300W Pressure: 5.0Torr Substrate temperature: 400 ° C Distance between electrodes: 250mils Gas partial pressure: Tetraethoxysilane: CF ₄ = 100: 5
00 sccm (however, tetraethoxysilane is introduced into the chamber by He bubbling, which is the flow rate of He) The element concentrations of C, F, Si, and O introduced into the formed thin film are shown in FIG. It can be seen from FIG. 2 that this thin film has a Si—CF bond. An electrode was formed on this film and the dielectric constant was measured. As a result, it was confirmed that the film had ε = 2.5 (frequency 1 MHz).

Next, as shown in FIG. 3, under the same conditions as described above, this insulating film is formed on a substrate on which aluminum wiring having a wiring thickness of 8000Å and a minimum line width of 0.5 μm is formed.
When heat treatment was performed at 0 ° C. and further oxygen plasma treatment was performed, film reduction and crack generation were not observed. Further, as a result of re-measurement of the dielectric constant after leaving it in the atmosphere for 2 weeks, no change in the dielectric constant was observed (FIG. 4).

Example 6 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate. Applied power: 13.56 MHz / 300 W Pressure: 1.0 Torr substrate temperature: 350 ° C. distance between electrodes: 250Mils gas partial _{pressure: (CH 3) 3 SiCF 3} : O 2 = 200: 3
00 sccm (however, (CH ₃ ) ₃ SiCF ₃ is introduced into the chamber by Ar bubbling, and is the flow rate of Ar). The infrared absorption spectrum of the formed thin film is shown in FIG.
The S chart is shown in FIG. It can be seen from FIGS. 5 and 6 that this thin film has a Si—CF bond. An electrode was formed on this film, and the dielectric constant was measured. As a result, it was confirmed that the film had ε = 2.51 (frequency 1 MHz).

Then, as shown in FIG. 3, under the same conditions as above, this insulating film is formed on a substrate provided with aluminum wiring having a wiring thickness of 8000 Å and a minimum line width of 0.5 μm.
When the heat treatment was performed at 0 ° C., neither film reduction nor generation of cracks was observed. Further, as a result of re-measurement of the dielectric constant after leaving it in the atmosphere for 2 weeks, no change in the dielectric constant was observed (FIG. 7). Furthermore, no change was observed in the measurement of adsorbed water by thermal desorption gas analysis (FIG. 8).

Example 7 A thin film was formed on a substrate on which five ring oscillators were formed under the same conditions as in Example 6, and through holes were provided so that the ring oscillators were connected in series. A substrate on which the second layer was formed and a substrate on which a tetraethoxysilane-SiO ₂ film was formed under the same conditions as in Example 6 except that the gas composition was changed were used as comparative materials.

As a result of comparing the wiring delays of the respective substrates, it was found that the substrate using the insulating film according to the present invention can reduce the wiring delay by about 25%. Example 8 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate.

Applied power: 13.56 MHz / 300 W Pressure: 1.0 Torr Substrate temperature: 350 ° C. Electrode distance: 250 mils Gas partial pressure: (CH ₃ ) ₃ SiCF ₃ : CF ₄ : O ₂ = 2
00: 100: 300 sccm The infrared absorption spectrum of the formed thin film is shown in FIG.
The S chart is shown in FIG. It can be seen from FIGS. 9 and 10 that this thin film has a Si—CF bond. An electrode was formed on this film and the dielectric constant was measured. Ε = 2.51
It was confirmed that the film had a frequency of 1 MHz.

Next, under the same conditions as above, the wiring thickness 80
When this insulating film was formed on a substrate provided with aluminum wiring having a line width of 00Å and a minimum line width of 0.5 μm, and heat treatment was performed at 500 ° C., no film reduction or crack generation was observed.
Further, as a result of re-measurement of the dielectric constant after leaving it in the atmosphere for 2 weeks, no change in the dielectric constant was observed (FIG. 7).
Furthermore, no change was observed in the measurement of adsorbed water by thermal desorption gas analysis (FIG. 8).

Comparative Example 2 Using a parallel plate type plasma CVD apparatus, S under the following conditions
A thin film having a thickness of about 0.5 μm was formed on the i flat plate. Applied power: 13.56MHz / 300W Pressure: 1.0Torr Substrate temperature: 350 ° C Distance between electrodes: 250mils Gas partial pressure: SiH ₄ : CF ₄ = 200: 300sccm Electrodes were formed on this film and the dielectric constant was measured. Result ε =
It was confirmed that the film was 3.20 (frequency 1 MHz).

Next, under the same conditions as above, the wiring thickness 80
When this insulating film was formed on a substrate provided with aluminum wiring having a line width of 00Å and a minimum line width of 0.5 μm, and heat treatment was performed at 500 ° C., no film reduction or crack generation was observed.
However, as a result of re-measurement of the permittivity after leaving it in the atmosphere for 2 weeks, the permittivity increased to ε = 3.20 (frequency 1 MHz) (Fig. 7). Further, in the measurement of adsorbed water by thermal desorption gas analysis, it was confirmed that the amount of adsorbed water increased by about one digit (FIG. 8).

[0032]

The silicon compound film according to the present invention exhibits a low dielectric constant, has a low hygroscopic property, and can form an insulating film having a low dielectric constant, and is effective in reducing wiring delay. Therefore, it is possible to provide a high-speed device and a highly reliable semiconductor integrated circuit and circuit board.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of a thin film obtained in an example.

FIG. 2 shows C, F, S introduced into the thin film obtained in the example.
The graph which shows the elemental concentration of i and O.

FIG. 3 is a schematic diagram for explaining an aluminum wiring forming process and a heat treatment test of a CVD thin film used in the examples.

FIG. 4 is a graph showing changes with time in the dielectric constant of the thin films obtained in the examples.

FIG. 5 is an infrared absorption spectrum diagram of the thin films obtained in the examples.

FIG. 6 is an XPS chart diagram of a thin film obtained in an example.

FIG. 7 is a graph showing changes with time of the dielectric constant of the thin films obtained in the examples.

FIG. 8 is a graph of the amount of adsorbed water of the thin film obtained in the example.

FIG. 9 is an infrared absorption spectrum diagram of the thin films obtained in the examples.

FIG. 10 is an XPS chart diagram of thin films obtained in Examples.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshihiro Nakata, 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Rinko Katayama, 1015, Kamikodanaka, Nakahara-ku, Kawasaki, Kanagawa

Claims (15)

[Claims] 1. The following general formula (1), R ¹ _x SiR ² _4-x (1) [wherein R ¹ represents an alkyl group having 1 to 6 carbon atoms, R ^1
2 represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms, and x is an integer of 1 to 3] and a gas of a fluorine-containing organic silane compound derived from fluorine or a fluorine compound. A silicon compound film made of a fluorocarbon group-containing silicon compound obtained by performing plasma CVD in an atmosphere containing, and having a dielectric constant of 3.0 or less. 2. The silicon compound film according to claim 1, wherein the fluorocarbon group-containing silicon compound is a fluorocarbon group-containing silicon oxide compound, a fluorocarbon group-containing silicon nitride compound or a fluorocarbon group-containing silicon nitride oxide compound. . 3. The following general formula (1), R ¹ _x SiR ² _4-x (1) [wherein R ¹ represents an alkyl group having 1 to 6 carbon atoms, R ^1
2 represents a hydrogen atom or an alkoxy group having 1 to 3 carbon atoms, and x is an integer of 1 to 3] and a gas of a fluorine-containing organic silane compound derived from fluorine or a fluorine compound. A method for forming a silicon compound film, which comprises performing plasma CVD in an atmosphere containing 4. A fluorocarbon group-containing silicon oxide compound, a fluorocarbon group-containing silicon nitride compound is obtained by performing plasma CVD in an atmosphere containing a fluorine-containing organosilane compound gas and oxygen gas, nitrogen gas or nitric oxide gas. Alternatively, the method of claim 3 wherein a fluorocarbon group-containing silicon nitride oxide compound is formed. 5. The method according to claim 3, wherein the gas generation of the fluorine-containing organosilane compound and the plasma CVD are performed in the same chamber. 6. A gas of a fluorine-containing organosilane compound is generated in a first chamber, and then this gas is introduced into a second chamber, where a plasma CV is performed in the second chamber.
The method according to claim 3 or 4, wherein D is performed. 7. The method according to claim 3, wherein the fluorine compound is a nitrogen fluoride compound or a fluorocarbon compound. 8. A semiconductor device including the silicon compound film according to claim 1 as an insulating film. 9. A semiconductor device comprising the silicon compound film according to claim 1 or 2 as a moisture resistant protective film. 10. An organosilane compound represented by the following general formula (2), R ³ ₃ SiCF ₃ (2) [wherein R ³ represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms]. A silicon compound film made of a fluorocarbon group-containing silicon compound obtained by performing plasma CVD in an atmosphere containing oxygen gas. 11. An organosilane compound represented by the following general formula (2), R ³ ₃ SiCF ₃ (2) [wherein, R ³ represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms]. A method for forming a silicon compound film, which comprises performing plasma CVD in an atmosphere containing oxygen gas. 12. The method according to claim 11, wherein fluorine gas is added to the atmosphere. 13. The fluorine gas is fluorocarbon, F ₂
The method according to claim 12, wherein the gas is NF ₃ gas. 14. A semiconductor device comprising the silicon compound film according to claim 10 as an insulating film. 15. A semiconductor device comprising the silicon compound film according to claim 10 as a moisture resistant protective film.