JPS62209831A - Manufacture of silicon oxide film - Google Patents

Abstract

PURPOSE:To facilitate formation of a high performance silicon oxide film which conforms to three conditions, i.e., small internal stress, high resistance and high deposition rate, by a method wherein a radio frequency power, which is applied when the silicon oxide film is deposited, is set at the specific magnification. CONSTITUTION:A plasma CVD apparatus is constituted by a vacuum reaction furnace, a vacuum pump system for evacuating the reaction furnace, a gas introducing system for introducing a material gas into the reaction furnace, a radio frequency source (frequency=13.56MHz) for generating a plasma and electrodes. When a silicon oxide film is deposited on a substrate by plasma CVD with the material gas containing silane system gas, a radio frequency power P applied to the reaction system is set within a range of 2-3.3 times of a saturation starting power Ps at which a deposition rate (D.R.) is saturated with predetermined temperature, gas flow and pressure. With this constitution, a silicon oxide film which conforms to conditions of small internal stress, high resistance and high deposition rate can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for manufacturing a silicon oxide film having high properties by plasma CVD.

[Conventional technology]

Silicon oxide film (Sin) has excellent insulating properties and low donor and acceptor diffusion coefficients, so it is widely used as a selective mask, interlayer insulation film, and passivation film in the manufacturing process of semiconductor devices. It is being

Methods for producing this silicon oxide film include high-temperature thermal oxidation, CVD, etc. Among the CVD methods, especially plasma carbon
The VD method is characterized by low film formation temperature. A conventional method of manufacturing a silicon oxide film using this plasma CVD method will be briefly described below. Using silane gas (SiH2) diluted with argon gas (Ar) and laughing gas (Nto) as raw material gases, the raw material gases are evacuated into a reaction system under reduced pressure (several Pa to several hundred Pa). Introduce while adjusting the flow rate. A high-frequency glow discharge is generated in this reaction system to create non-equilibrium plasma, and a silicon oxide film is deposited on the substrate as a deposition target by a chemical reaction in the gas phase of the decomposition product or on the substrate. Note that the substrate temperature at this time is maintained at approximately 200 to 300°C (journal
Otsu Electrochemical Society: Solid-State Science and Technology p) (J, Elect
rochem, Soc, :5OLID-8TATE
5CIENCE AND TECHNOLOGY
) Vol, 128 Nl 71981 (July)
P, 1545-1551).

[Problem that the invention seeks to solve]

However, when forming a silicon oxide film using the above-mentioned plasma CVD method, the formation conditions largely depend on temperature, high frequency power, gas components, etc., and the silicon oxide film formed is amorphous and thermally unstable. Coupled with the fact that the internal stress (compressive stress or tensile stress) is extremely large due to the quasi-equilibrium state, there is a problem in that it is difficult to obtain sufficient basic characteristics under optimal forming conditions.

In fact, when a thick silicon or silicon oxide film is formed for the purpose of electrical insulation or padding, cracks in the film and peeling from the substrate tend to occur.

Furthermore, when applied to the manufacturing process of semiconductor devices, it is necessary to suppress the internal stress described above, and also satisfy the conditions of high resistance and high deposition rate, which has conventionally been an important problem in the manufacturing process.

Therefore, the present invention has been made to solve the above problems, and focuses on high frequency power among the formation conditions, and creates a silicon oxide film that simultaneously satisfies the three conditions of low internal stress, high resistance, and high deposition rate. The purpose is to provide a manufacturing method for.

[Means for solving problems]

The method for manufacturing a silicon oxide film according to the present invention uses a raw material gas containing a silane gas to deposit a silicon oxide film on a substrate by plasma CVD, and the high frequency power applied to the reaction system is applied to a predetermined substrate. The temperature, gas flow rate, and atmospheric pressure are set in a range of 2 to 3.3 times the saturation starting power at which the deposition rate is saturated.

[For production]

According to the present invention, since the above-described method is adopted when manufacturing a silicon oxide film, it is possible to form a silicon oxide film with low internal stress, high resistance, and high deposition rate.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on FIGS. 1 to 3. As is well known, a plasma CVD apparatus consists of a vacuum reactor, a vacuum pump system to make the reactor a vacuum, a gas introduction system to introduce raw material gas into the reactor, and a high-frequency power supply (waste) to generate plasma. Wave number -13,56M
Hz) and electrodes.

Glass, metal, crystalline silicon, or the like is used as the substrate on which the silicon oxide film (Sin2) is deposited. Then, the substrate is placed on the ground-side electrode, and the reactor is evacuated to a predetermined ultimate vacuum level.

Next, silane gas (St) diluted to 1% with hydrogen gas (Hl) as a raw material gas and laughing gas (N, O) were mixed at a flow rate ratio (NtO:l (SiH*) = 120). Using a mixed gas, the gas flow rate is 0.5 to 3 SL.
The pressure inside the reactor was increased to 80°C.
Maintain the pressure at ~120 Pa. When a high frequency electric field is applied to the electrode in this state to cause glow discharge, the source gas is decomposed by the energy of the glow discharge and a silicon oxide film is deposited on the substrate. At this time, the substrate temperature is maintained at about 200 to 300°C.

Here, when the high frequency power P is changed from 0 to 250 Wt, the deposition rate R, the high frequency power P dependence of R, +, J-inner tube 16"711/; tei-h frn/l-f
's, M 1 7%j ■61 pregnancy 11f
6) An Rfp region is obtained. Note that FIGS. 2 and 3 show the high-frequency power of internal stress S and resistivity R when the substrate temperature is set to 230°C, the gas flow rate of the above-mentioned raw material gas is set to 1.58LM, and the pressure inside the reactor is set to 100 PaK. This shows the dependence of each. In addition, when measuring resistivity, the measurement electric field is set to I MV/cm, 2 MV/an, and 3 MV/an.
There are three levels: m.

The relationship between high frequency power, deposition rate, internal stress, and resistivity in each region will be described below. First, area (1)
is the region where the deposition rate increases in proportion to the radio frequency power;
In FIGS. 2 and 3, this corresponds to the range O≦P≦60.

As for the internal stress, the compressive stress increases in proportion to the increase in high frequency power (Fig. 2) c.

Furthermore, the electrical resistivity slightly decreases at each level as the high frequency power increases.

Next, region (n) is a region where the deposition rate is saturated as the radio frequency power increases.If the radio frequency power that starts saturation, that is, the saturation start power, is Ps (Fig. 1), then Ps < P.
<2.7 Ps. In FIGS. 2 and 3, this corresponds to a range of 60≦P≦120. Note that the substrate temperature was 230°C and the gas flow rate was 1.5SLM.

Under the above conditions of pressure 100 Pa, the saturation start value of the deposition rate is about 160 A/-. As shown in FIG. 2, the internal stress changes from compressive stress to tensile stress as the high frequency power P increases in this region.

For this reason, there is a high frequency power P0 (FIG. 1) that makes the internal stress zero in the middle. In Figures 2 and 3, PO=12
It is 0W. The film deposited with Po has a maximum resistivity as shown in FIG.

The region (In) is a region that shows an increasing tendency again after the deposition rate is saturated (depending on the formation conditions, it may not show an increase, but the trends of internal stress and resistivity, which will be described later, do not change). Figure 2 and 3rd Fl! In J, this corresponds to P≧160. As shown in FIG. 2, the internal stress changes from tensile stress to compressive stress as the high frequency power P increases. For this reason,
A high frequency power pt (FIG. 1) that makes the internal stress zero again exists in this region. In Figures 2 and 3, pi=2o
It is OW. Also, the resistivity is the 3rd Fg! J decreases as the high frequency power P increases.

From the point of view of internal stress, it is ideal that internal stress = 0, but considering the adhesion between the substrate and the coating, there is no practical problem if both compressive and tensile stress are within about I x 10' dyne/-. do not have. On the other hand, the resistivity shows a high resistivity exceeding 1014Ω・G over a wide range at each level.
This value is sufficient for application to the manufacturing process of semiconductor devices.

As mentioned above, the high frequency power that provides a small internal stress that does not cause peeling of the film from the substrate is 2 Pa≦P≦3, where Pa is the saturation starting power at which the deposition rate starts to become saturated.
．． It is in the range of 3 Ps. In terms of Figures 2 and 3,
This corresponds to 120≦P≦200.

By using the conditions in the above range, it is possible to form a silicon oxide film that satisfies the three conditions of low internal stress, high resistance, and high deposition rate.

〔Effect of the invention〕

As explained in detail above, according to the present invention, when depositing a silicon oxide film on a substrate by plasma CVD using a raw material gas containing a silane gas, the applied high frequency power is adjusted to a predetermined gas flow rate. Since the pressure inside the reactor was set between 2 and 3.3 times the saturation start power, which gives the start of saturation of the deposition rate, the three conditions of low internal stress, high resistance, and high deposition rate were simultaneously satisfied. A silicon oxide film with high properties can be obtained.

Therefore, the present invention improves the characteristics and reliability of semiconductor devices, and has extremely high industrial utility value.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the dependence of deposition rate on high frequency power in the present invention, Figure 2 is a characteristic diagram showing the dependence of similar internal stress on high frequency power, and Figure 3 is a similar diagram showing the dependence of resistivity on high frequency power. FIG. Ps...Saturation start power that gives the start of saturation of the deposition rate;
Po = Pt... High frequency power that gives internal stress = 0. Patent applicant: Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) Plasma C using source gas containing silane gas
In a method for manufacturing a silicon oxide film in which a silicon oxide film is deposited on a substrate by the VD method, the high frequency power applied to the reaction system is adjusted to a saturation start power that starts to saturate the deposition rate at a predetermined substrate temperature, gas flow rate, and atmospheric pressure. A method for manufacturing a silicon oxide film, characterized in that the film is set in a range of 2 to 3.3 times.