JPH02218130A - Silicon carbide oxynitride thin film and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an insulating thin film characterized by high perforance by forming the thin film by using the mixed gas of hydrogenized silicon gas such as monosilane, nitrogen gas and carbon monoxide gas or the mixed gas of silicon hydride, nitrogen gas and carbon dioxide gas. CONSTITUTION:A microwave is introduced into a plasma generating chamber from a microwave oscillator 13 through a waveguide 12. A magnetic field is applied in the plasma generating chamber with an electromagnet 15. The mixed gas of SiH4, CO2 and N2 or the mixed gas of SiH4, CO and N2 is introduced through a gas introducing port 16 as a raw material gas. For example, the pressure in a reaction container is kept at 1.0mTorr. When plasma 17 having a high degree of dissociation is generated, the plasma 17 reaches a substrate holder 19 through a plasma drawing window 18. Silicon carbide oxynitride is formed on a substrate 20. Thus, an insulating thin film characterized by fine structure and less inner strain can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention mainly relates to a method for manufacturing an insulating thin film called silicon carbide oxynitride (silicon carbide oxynitride) at a relatively low temperature near room temperature. be.

2. Description of the Related Art Conventionally, when silicon oxynitride was formed as a protective film for a semiconductor device by plasma decomposition using microwave electron cyclotron resonance absorption, a manufacturing apparatus having a configuration as shown in FIG. 3 was used.

A vacuum chamber 31 is evacuated to a vacuum through an exhaust hole 32. Microwaves are introduced from a microwave oscillator 34 into a plasma generation chamber 35 through a waveguide 33 . electromagnet 36
A magnetic field is applied to the plasma generation chamber 35 by this. 37
The raw material gases such as 5IH4, Ne, Neo, 02, etc. are introduced at the gas inlet, and the pressure inside the reaction vessel is, for example, 1, Q.
Keep it at about uTorr. Plasma with a high degree of dissociation can be obtained by setting the strength of the magnetic field so as to satisfy the electron cyclotron resonance conditions. The generated plasma passes through the plasma extraction window 38 and reaches the substrate holder 39, where silicon nitride, silicon oxynitride, silicon oxide thin film, etc. are deposited on the substrate 40 on the holder 39.

Problems to be Solved by the Invention However, in the case of such conventional insulating films, for example, in the case of silicon nitride, high quality silicon nitride could be obtained even if monosilane and nitrogen gas were used as source gases and deposited. There is a problem in that the stress generated inside the film is large and cracks are likely to occur, which limits the scope of its application to devices. On the other hand, in the case of silicon oxide and silicon oxynitride, silane gas, nitrogen (N, ), and oxygen (O2) are used.
Since it uses gas, it causes a reaction between the gases in the plasma, and the film is formed with poor adhesion to the substrate, which causes the problem of easy peeling.It is also used as a wear-resistant layer in image sensors and thermal heads. In this case, there was a major problem in that the hardness was insufficient.

The present invention aims to solve such problems.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides that at least four elements, silicon, carbon, oxygen, and nitrogen, form the basic skeleton of the solid thin film, and that the coordination number of the carbon element is The present invention provides an oxynitride silicon carbide film characterized in that the number is 2 to 4. In addition, in the present invention, a silicon nitride film was conventionally formed using a mixed gas of monosilane and nitrogen as a raw material gas, but in the present invention, a hydrogenated silicon gas such as monosilane or disilane is used as a raw material gas. It has been found that the above problems can be solved by forming a 5iCON film using nitrogen gas and carbon oxides such as CO and COa as raw material gases, and by adjusting the microwave power to an appropriate value. The present invention provides a high-performance insulating thin film and a manufacturing method for realizing the same by the above-mentioned means.

Effects The effects of the present invention produced by using the above-mentioned means are as follows. In the conventional method, a silicon oxynitride (silicon oxynitride) film is formed using a mixed gas of monosilane, oxygen, and nitrogen as a raw material gas, and films with properties intermediate between SiN and 5i02 are selectively used. .

By using carbon dioxide (CO2) in the present invention, a large amount of nitrogen, which is highly excited in the plasma, is incorporated into the film and the internal strain in the film cannot be removed. By efficiently combining carbon, oxygen, and nitrogen with silicon atoms, it is possible to form an excellent insulating thin film with a dense structure and low internal strain.In addition, the internal stress can be adjusted simply by adjusting the microwave power, and the film It is possible to easily change the properties continuously.

EXAMPLE 1 As a first example, an example in which a silicon oxynitride thin film is formed at room temperature using the manufacturing method of the present invention will be described.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Representative embodiments of the present invention will be shown below based on the drawings. FIG. 1 is a schematic diagram of the apparatus used in the present invention. 10 is a vacuum chamber, which is evacuated to a vacuum through an exhaust hole 11. Microwaves are introduced from a microwave oscillator 13 into a plasma generation chamber 14 through a waveguide 12 . A magnetic field is applied to the plasma generation chamber 14 by the electromagnet 16 . 16 is a gas inlet port for a mixed gas of 5IH4, CO2, and N2 or 5I
A mixed gas of H4, CO and N2 is introduced as a raw material gas, and for example, the pressure inside the reaction vessel is set to 1, Q a + TOrr
Keep it at a moderate level.

Plasma 17 with a high degree of dissociation is generated by setting the strength of the magnetic field in the plasma generation chamber to satisfy electron cyclotron resonance conditions. The generated plasma passes through the plasma extraction window 18 and reaches the substrate holder 19, where silicon carbide oxynitride is formed on the substrate 20. At this time, for example, the mixing ratio of 5iHa, Co, and Na should be set to a value between 1:10:50 and 1:100:50, and the microwave power should be set to a power that can well excite each source gas. Accordingly, it is possible to form a 5iCON film of any composition. Second
The figure shows changes in the Vickers hardness of the film when the gas flow rate ratio of 5iHa and N2 is constant and the CO flow rate is varied. As can be seen from FIG. 2, it can be seen that the hardness can be adjusted by changing the CO flow rate. Of course Si
When the mixing ratio of H4 and N2 is changed, the rate of these changes also changes.

FIG. 4 shows the change in internal stress in the film when deposited on a single-crystal silicon substrate while keeping the gas flow rate ratio of SiH4 and N2 constant and varying the CO gas flow rate. Fourth
As can be seen from the figure, the stress can be made very small by changing the co flow rate. In this embodiment, the substrate was kept at room temperature, but there is no problem in forming at a higher temperature as long as the substrate is not damaged.

Although this embodiment has been described using the ECR plasma CVD method, substantially the same effect can be obtained by heating the substrate at 200 to 400° C. in the so-called general plasma CVD method. However, since general plasma may be more difficult to excite than ECR plasma depending on the type of gas, it goes without saying that it is necessary to reset the flow rate ratio of each gas to an appropriate value.

Furthermore, in this example, monosilane (SiHa) was used as the hydrogenated silicon gas and CO gas was used as the carboxylic oxygen gas, but disilane (SiHa) was used instead of monosilane.
It goes without saying that the same effect can be obtained by using CO2 instead of .

Effect of the invention The effects of the present invention are as follows.

First, as shown in the examples, the Vickers hardness of the membrane can be easily adjusted by changing the CO flow rate. In addition, the deposition rate at this time does not change much if microwave power is applied to a certain extent, so even when trying to obtain a film with different hardness, the productivity can be improved by changing the deposition rate. It can be said that there is no decrease in

Furthermore, a film with very low stress can be obtained by adjusting the microwave power.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the ECR plasma CVD apparatus used for forming the silicon carbide oxynitride thin film of the present invention, Figure 2 is a diagram showing the CO dependence of Vickers hardness, and Figure 3 is a diagram showing the CO dependence of Vickers hardness.
The figure is a schematic diagram of a conventional ECR plasma CVD apparatus, and FIG. 4 is a diagram showing the dependence of internal stress in a film on CO meteors. 10... Vacuum chamber 11... Exhaust hole, 12.
...Waveguide, 13...Microwave oscillator, 14...
Plasma generation chamber, 15... Electromagnet, 16... Gas inlet, 17... Plasma, 18... Plasma drawer window, 19... Name of substrate holder agent Patent attorney Shigetaka Awano 1 person Figure COf, l love (, gcCx) Figure 0 CO3 hypertrophy (ΔCcrrL)

Claims (3)

[Claims] (1) A silicon oxynitride silicon carbide thin film, characterized in that at least four elements, silicon, carbon, oxygen, and nitrogen, form the basic skeleton of the solid thin film, and the carbon element has a coordination number of 2 to 4. (2) In the method for producing a silicon oxynitride silicon carbide thin film, in the process of depositing the thin film by plasma decomposition using a high frequency, direct current or alternating current electric field, at least hydrogenated silicon gas such as monosilane, nitrogen gas and carbon monoxide (
A method for producing a silicon oxynitride silicon carbide thin film, characterized in that it is formed using a mixed gas of silicon hydride, nitrogen gas, and carbon dioxide (CO_2) gas. (3) In the method for producing an oxynitride silicon carbide thin film, at least a mixed gas of silicon hydride gas such as monosilane, carbon oxide gas, and nitrogen gas, or a mixture of silicon hydride, carbon oxide, nitrous oxide, and nitrogen gas is used. A method for producing a silicon oxynitride silicon carbide thin film, characterized in that it is formed using a mixed gas.