JPH0766129A - Plasma cvd system - Google Patents

Abstract

PURPOSE:To provide a plasma CVD system in which generation of particle is suppressed while enhancing the grow rate of film being formed on the surface of a wafer and making the film quality uniform. CONSTITUTION:High frequency power is fed to a pair of electrodes 4, 5 disposed in a reaction chamber 8 and the atmospheric gas therein is converted into plasma thus activating the surface of a wafer 13. Consequently, the grow rate of film is increased and the film quality is made uniform. Necessary ions are selected from ions fed from an ion source 2 by means of an analytic magnet 3 and fed into the reaction chamber 8 where the ions are concentrated onto the surface of the wafer 13 through the electric field formed between the electrodes 4, 5 and then the ions are trapped. This constitution prevents the ions from being trapped by the side wall of reaction chamber an generating particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD apparatus applied to the manufacture of semiconductor devices.

[0002]

2. Description of the Related Art A conventional plasma CVD apparatus will be described with reference to FIG. The inside of the reaction chamber 8 is depressurized by using a vacuum pump 10. Then, the reactive gases at the set flow rates are mixed by the mass flow controller 1 and introduced into the reaction chamber 8. The inside of the reaction chamber 8 is kept at a set pressure by a pressure adjusting valve 9. Further, the wafer 13 is heated by the heater 12 in the susceptor 5 and has a constant temperature. In this state,
No film formation reaction has occurred.

Next, when a high frequency is applied to the upper electrode 4 and the susceptor 5 by the high frequency power source 6, as shown in FIG. 5, reaction gas SiH ₄ radicals, SiH ⁴⁺ ions, and atmosphere gas N ₂ O are generated. Radical O ^2- oxygen ions coexist. When these ions reach the susceptor 5, they receive the energy of heat to form a film. But the energy of heat is
Film formation is seen not only on the susceptor but also on the side wall of the reaction chamber due to the influence of heat radiation, which causes particles to be generated.

[0004]

This conventional film forming method,
For example, in SiO ₂ using SiH ₄ , SiH ₄ and N ₂ O are used as reactive gases. In the plasma excited state, SiH ⁴⁺ + O ² + + W ₁ (heat energy from the heater) → SiO ₂ + 3 / 2H ₂ ↑ However, SiH ₄ and N ₂ O do not originate from the reaction. Thermal CVD
Then, SiH ₄ + 2N ₂ O + W ₂ (temperature energy in the furnace) → SiO ₂ + 2H ₂ ↑ + 2N ₂ ↑ W ₁ <W ₂ (There is a difference of about 400 ° C. in terms of temperature).

As described above, in the plasma CVD apparatus, W
_{Since 1} is a relatively low temperature, there is a high probability that it will react in the gas phase before reaching the heater part, and the generation of particles cannot be avoided. In addition, SiH ⁴⁺ and N ₂ O ⁺ generate not only those having a uniform energy level but also scattering that significantly reduces the reaction efficiency when SiO ₂ is produced.

The third problem is that SiH ^{3 −} , Si
The film quality is not uniform because ions and molecules such as H ₂ ²⁺ and NO are generated secondarily. As described above, the conventional plasma CVD apparatus has the above problems.

It is an object of the present invention to provide a plasma CVD apparatus in which ions for plasma CVD growth are concentrated and trapped on the wafer surface after activation of the wafer surface with an atmospheric gas.

[0008]

To achieve the above object, a plasma CVD apparatus according to the present invention has an activation processing section and a film formation processing section, and applies high frequency power to a pair of electrodes in a reaction chamber. A plasma CVD apparatus for processing a wafer with a plasma gas generated between a pair of electrodes, wherein the activation processing unit supplies an atmosphere gas into the reaction chamber, and the wafer is heated by the atmosphere gas plasmatized between the pair of electrodes. The surface is activated, and the film formation processing section supplies ions for plasma growth into the electric field formed between the pair of electrodes, and the plasma growth ions plasmatized between the pair of electrodes, The film formation process is performed on the wafer surface. The activation processing unit and the film formation processing unit are driven and controlled independently, and the film formation processing unit performs the activation process by the activation processing unit.
It is driven.

Further, the activation processing section has an atmosphere gas supply source, and the atmosphere gas supply source supplies the atmosphere gas into the reaction chamber prior to the film formation processing of the wafer by the film formation processing section.

Further, the film forming processing section has an ion source and an ion selecting section and starts the operation after the operation of the atmosphere gas supply source. The ion source ionizes the reaction gas, The ion selector selects the ions necessary for plasma growth from the ionized reaction gas and supplies them to the reaction chamber.The activation processor selects the ions. An electric field for attracting the ions for plasma growth selected in the section to near the wafer is formed between the pair of electrodes.

Further, the film forming processing section accelerates the plasma growth ions by the ion accelerator and supplies them to the electric field between the electrode pair.

[0012]

The atmosphere gas sent into the reaction chamber is turned into plasma to activate the wafer surface, thereby increasing the film growth rate on the wafer surface and making the film quality uniform.

Further, by utilizing the electric field generated when the atmospheric gas is turned into plasma, the ions for film growth are trapped by being concentrated on the wafer surface.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a structural sectional view showing Embodiment 1 of the present invention, and FIG. 2 is a view showing a state of an electric field when plasma is generated in a reaction furnace.

In FIG. 1, a pair of upper electrode 4 and a susceptor (electrode) 5 are arranged in a reaction chamber 8 so as to face each other vertically, and a high frequency power source 6 is provided between the electrode 4 and the susceptor 5. Are connected. Further, a vacuum pump 10 is connected to the reaction chamber 8 via a pressure adjusting valve 9, and a mass flow controller for atmospheric gas (atmospheric gas supply source).
7 is connected to the reaction chamber 8.

Further, an ion source 2 is connected to the reaction chamber 8 via an analysis magnet (ion selecting section) 3, and a mass flow controller 1 for reaction gas is connected to the ion source 2. The susceptor 5 has a heater 1
2 is equipped.

Here, the upper electrode 4, the susceptor 5, the high frequency power supply 6, the atmosphere gas mass flow controller 7, etc. constitute an activation processing section, and the activation processing section is a pair of electrodes 4, 5 to which high frequency power is applied. Atmosphere gas is supplied between
Atmosphere gas generated between the pair of electrodes 4 and 5 is activated on the surface of the wafer 13, and the plasma CV
An electric field for attracting D growth ions to the vicinity of the wafer 13 is formed between the electrodes 4 and 5.

Further, the reaction gas mass flow controller 1, the ion source 2, the analysis magnet 3 and the like constitute a film forming processing section, and the film forming processing section is exposed to an electric field formed between the pair of electrodes 4 and 5. Ions for plasma growth are supplied, and film formation processing is performed on the surface of the wafer 13 by the ions for plasma growth that have been turned into plasma between the pair of electrodes 4, 5.

The activation processing section and the film formation processing section are independently driven and controlled, and the film formation processing section is driven after the activation processing is performed by the activation processing section.

In FIG. 1, the atmospheric gas controlled by the atmospheric gas mass flow controller 7 is introduced into the reaction chamber 8 and excited by the high frequency power source 6 to generate plasma. The surface of the wafer 13 is activated by this plasma.

Next, the reaction gas is introduced into the ion source 2 under the control of the reaction gas mass flow controller 1 and ionized by the ion source 2. After that, of the ions from the ion source 2, only the necessary ions are extracted by the analysis magnet 3 and introduced into the reaction chamber 8, and these ions are transferred to the wafer 1.
3 is distributed on the surface and film formation is performed. In this case, ions are induced on the surface of the wafer 13 by the electric field formed between the electrodes 4 and 5, so that the ions are transferred to the wafer 13.
Trapped on the surface of the.

(Embodiment 2) FIG. 3 is a structural sectional view showing Embodiment 2 of the present invention. In FIG. 3, the process from the atmosphere gas introduction to the plasma generation is the same as that in the first embodiment.

In introducing reactive ions, the reactive gas is supplied from the mass flow controller 1 for the reactive gas to the ion source 2
And the reaction gas is ionized in the ion source 2. The ionized reactive gas is selected by the analysis magnet 3 and then guided to the ion accelerator 11 to be formed into an ion beam to reach the surface of the wafer 13 on the susceptor 5 for film formation. The acceleration voltage of the ion accelerator 11 changes periodically as shown in FIG.

Atoms ionized by the ion source 2 change their kinetic energy by the acceleration voltage of the ion accelerator 11, and reach the ion accelerator and the diagonal end when the acceleration voltage is maximum. The in-plane variation of the arriving ions on the wafer can be suppressed by periodically changing the acceleration voltage.

[0026]

As described above, according to the present invention, the atmospheric gas in the reaction chamber is turned into plasma by high frequency power,
Since the wafer surface is activated, the film growth rate can be increased and the film quality can be made uniform on the wafer surface.

Further, since the plasma CVD growth ions are supplied to the film to form a film in the electric field concentrated in the wafer region, the plasma CVD growth ions are generated in the surface of the wafer by the action of the electric field. Therefore, it is possible to suppress the generation of particles by reducing the rate of attachment to the side wall of the reaction chamber and the like by being concentrated and trapped. By suppressing the generation of particles, it is possible to reduce the number of cleanings in the reaction chamber to improve productivity, and prevent contamination of wafers by particles to improve the product yield.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing movements of ions and electrons when a high frequency is applied between both electrodes.

FIG. 3 is a structural cross-sectional view showing a second embodiment of the present invention.

FIG. 4 is a diagram showing an acceleration voltage-time applied to an ion accelerator.

FIG. 5 is a structural cross-sectional view showing a conventional device.

[Explanation of symbols]

 1 Mass Flow Controller for Reaction Gas 2 Ion Source 3 Analysis Magnet 4 Upper Electrode 5 Susceptor 6 High Frequency Power Supply 7 Mass Flow Controller for Atmosphere Gas 8 Reaction Chamber 9 Pressure Control Valve 10 Vacuum Pump 11 Ion Accelerator 12 Heater 13 Wafer

Claims (4)

[Claims] 1. A plasma C, which has an activation processing section and a film formation processing section, applies high-frequency power to a pair of electrodes in a reaction chamber, and processes a wafer with a plasma gas generated between the pair of electrodes.
In the VD apparatus, the activation processing unit supplies an atmospheric gas into the reaction chamber, and activates the wafer surface by the atmospheric gas plasmatized between the pair of electrodes. Ions for plasma growth are supplied to the electric field formed between the pair, and the film formation processing is performed on the wafer surface by the plasma growth ions that are turned into plasma between the pair of electrodes. The plasma C is characterized in that it is driven and controlled independently of the film processing unit, and that the film formation processing unit is driven after the activation processing is performed by the activation processing unit.
VD device. 2. The activation processing section has an atmosphere gas supply source, and the atmosphere gas supply source supplies the atmosphere gas into the reaction chamber prior to the film formation processing of the wafer by the film formation processing section. The plasma CV according to claim 1, wherein
D device. 3. The film formation processing section has an ion source and an ion selection section, and starts the operation after the operation of the atmospheric gas supply source. The ion source ionizes the reaction gas, The ion selector selects the ions necessary for plasma growth from the ionized reaction gas and supplies them to the reaction chamber.The activation processor selects the ions. The plasma CVD apparatus according to claim 2, wherein an electric field for attracting the ions for plasma growth selected in the section to the vicinity of the wafer is formed between the pair of electrodes. 4. The plasma according to claim 1, wherein the film forming processing unit accelerates the plasma growth ions by an ion accelerator and supplies the ions to the electric field between the electrode pair. CVD equipment.