JPS6380540A - Plasma apparatus - Google Patents

Abstract

PURPOSE:To increase the plasma generating efficiency for improving the manufacturing efficiency and to ensure stable operation for a plasma apparatus independently from types of film to be deposited, by providing the plasma apparatus with a plasma generating chamber having a structure serving as a cavity resonator with respect to microwave power introduced thereinto and by adapting the plasma apparatus such that the microwave source can be driven either continuously with constant-voltage direct current or intermittently at a frequency higher than a commercial frequency by switching power supplies. CONSTITUTION:A plasma apparatus according to the invention comprises a first power supply 183 for driving a microwave source 11 intermittently at a frequency higher than a commercial frequency, a second DC power supply 181 for driving microwaves continuously and switching devices l9a and 19b for switching over the first and second power supplies and connecting one of them to the microwave source. A plasma generating chamber 1 has a structure serving as a cavity resonator with respect to microwave power introduced into the chamber. Therefore, resonance is caused by driving the microwave source 11 and introducing microwaves into the chamber. If the microwave source is driven intermittently, the plasma generating chamber 1 functions as a cavity resonator according to its original design and provides a high plasma generating efficiency. As a result, a high film deposition rate and a high etching rate can be obtained. In the case of forming an amorphous silicon film, however, the microwave source 11 is driven continuously by the second power supply 181 since generated plasma is instable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is directed to CVD (Chemistry) for manufacturing semiconductor devices.
The present invention relates to a plasma device that utilizes electron cyclotron resonance, which is commonly used in calVapor deposition devices, edging devices, sputtering devices, and the like.

[Prior art]

Plasma devices using electron cyclotrons can generate highly active plasma at low gas pressure, allow a wide range of ion energies to be selected, and can generate large ion currents and improve the directionality of the ion flow.

It has advantages such as excellent uniformity, and its research and development are progressing as it is essential for manufacturing highly integrated semiconductor devices.

FIG. 1 is a longitudinal sectional view of a plasma device utilizing electron cyclotron resonance configured as a plasma CVD device, and 1 indicates a plasma generation chamber. Plasma generation chamber 1
is equipped with a cooling water circulation chamber 13 with a surrounding wall having a double structure,
Furthermore, a microwave inlet 1a sealed with a quartz glass plate 6 is provided in the center of the side wall, and a plasma outlet 1b is provided in the center of the other side wall opposite to the microwave inlet 1a. One end of a waveguide 7 is connected to the microwave inlet 1a, and a reaction chamber 2 is disposed 5 nm apart from the plasma outlet 1b, and furthermore, a plasma generation chamber 1 and a chamber connected thereto are arranged around the microwave inlet 1a. An excitation coil 4 is disposed concentrically with one end of the waveguide 7 so as to surround them.

In the middle of the waveguide 7 is a matching box 8 and a microwave power monitor 9.
, an isolator 10, the other end of which is connected to a microwave source 11 such as a magnetron, and a sample 15 such as a half-quad wafer placed in the reaction chamber 2, facing the plasma outlet 1b. A mounting table 16 is installed, and an exhaust port 17 connected to the exhaust system is installed on the wall facing the back side of the mounting table 16 in the reaction chamber 2.
It is forced to open.

In addition, 18 is a power source for the microwave source 11, and 13.14 is an air supply pipe for supplying raw material gas to each of the plasma generation chamber 1 and the reaction chamber 2.

In such a plasma CVD apparatus, the sample 15 is placed on the mounting table 16, and the plasma generation chamber 1 is
While introducing gas into the chamber through the air supply pipe 13, a DC voltage is applied to the excitation coil 4 and microwaves are introduced through the waveguide 7 to generate plasma within the plasma generation chamber 1, and the generated plasma is excited. A diverging magnetic field, which is formed by the coil 4 and whose magnetic flux density decreases toward the reaction chamber 2 in front of the plasma extraction port 1b, is projected toward the sample 15 in the reaction chamber 2, turning the gas in the reaction chamber 2 into plasma. The sample 15 is decomposed to form a thin film such as a silicon oxide film on the surface of the sample 15.

[Problem that the invention seeks to solve]

In general, semiconductor device manufacturing equipment is required to have high production efficiency, and in particular, it is desired to improve the reaction speed of thin film formation and etching. However, the conventional plasma apparatuses described above have not been able to fully meet this demand.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plasma device that can increase plasma generation efficiency and achieve high production efficiency, and can operate stably regardless of the type of film. shall be.

[Means for solving problems]

A plasma device according to the present invention is a plasma device in which microwaves emitted by driving a microwave generation source are guided to a plasma generation chamber to generate plasma by electron cyclotron resonance. On the other hand, a plasma generation chamber having a cavity resonator structure,
A first power source that drives the microwave source intermittently at a frequency higher than the commercial frequency, and a second power source that continuously drives the microwave source with direct current.
Power supply and 1st. It is characterized by comprising a switching device that switches the second power source and connects it to the microwave source.

In other words, the microwave source, which conventionally was driven continuously with constant voltage direct current, can now be switched and driven intermittently at a frequency higher than the commercial frequency.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

The overall configuration of the plasma apparatus according to the present invention is similar to that shown in FIG. 1, and the difference lies in the power source 18 of the microwave source such as a magnetron.

FIG. 2 shows the configuration of this power supply 18. A commercial frequency three-phase AC current tA181 is applied to a three-phase full-wave rectifier circuit 182 equipped with a smoothing circuit to obtain a DC voltage as shown in FIG. At the same time, a single-phase AC power supply 183 at a commercial frequency is supplied to a single-phase full-wave rectifier circuit 184 without a smoothing circuit, so that the power supply is twice the commercial frequency as shown in FIG. A pulsating voltage having a frequency of None as can be given to txu. switch 19
a and 19b are turned on and off in a complementary manner, and the voltage of either one is applied to the microwave source 11.

4 and 6 show microwave output waveforms when the voltages shown in FIGS. 3 and 5 are applied to the microwave source 11, respectively.

FIG. 7 shows another embodiment of the power supply of the present invention, in which a commercial frequency three-phase AC power source 181 is applied to a three-phase full-wave rectifier circuit 182 having a smoothing circuit to generate a DC voltage as shown in FIG. and connects it to the microwave source 11 via the switch 19b.
At the same time, the output of the full-wave rectifier circuit 182 is sent to the switch 1.
9a to the chopper circuit 185 to obtain a pulsed voltage as shown in FIG. 8, which is then applied to the microwave source 11 via the switch 19a2.

Switches 19b, 19a+, and 19az are turned on in a complementary manner.

The microwave source 11 is turned off and one of the voltages is applied to the microwave source 11.

FIG. 9 shows the microwave output when the voltage shown in FIG. 8 is applied to the microwave source 11.

In the embodiment shown in FIG. 2, the single-phase alternating current amount a183. A full-wave rectifier circuit 184 is connected to the first power source, and a three-phase AC power source 181
, the full-wave rectifier circuit 182 corresponds to the second power supply, and in the embodiment shown in FIG.
82 and the chopper circuit 185 correspond to the first power source, and the three-phase AC power source 181 and the full-wave rectifier circuit 182 correspond to the second power source.

It goes without saying that the configuration of the power source of the present invention is not limited to the above two embodiments, and the switching device that switches between them to supply power to the microwave source 11 is not limited to that of the above embodiments.

The device of the present invention as described above has Si203, Si:+N4
In order to improve the efficiency of film formation, the microwave source 11 is driven by the first power source. Although this driving is intermittent, high film-forming efficiency and excellent physical properties can be obtained for reasons described later. On the other hand, when forming an amorphous silicon film, plasma generation becomes unstable if the microwave source is driven intermittently, so the microwave source 11 is driven by the second power source. This drive is a continuous drive similar to the conventional one.

〔effect〕

FIGS. 10 and 11 are graphs showing the effects of the present invention, in which (a) the B etching rate of the three films, (b1 the refractive index of the gJ film, (C1
The thin film formation speed is shown respectively. In the figure, the black circles indicate the case when the microwave source is continuously driven by direct current using the conventional device, the white triangles indicate the case when the microwave source is intermittently driven at 60 Hz, and the white circles indicate the case when the microwave source is driven continuously by DC.
The results are shown in the case of intermittent driving at 0 Hz. In addition, in Fig. 10, when the microwave power is 300,
FIG. 11 shows the case where the microwave power is 15 times.

Looking at (a) of both figures, except for the high gas pressure (gas pressure in the reaction chamber) area in the case of 150-, the BHF is higher with the device of the present invention than with the conventional device, which is indicated by white triangles and white circles.
It can be seen that the etching rate is low and a more sensitive thin film is formed in the case of the present invention.

Furthermore, as is clear from (g)), the device of the present invention provides stable characteristics with a refractive index of around 1.95.

Furthermore, looking at (C), it can be seen that the film formation rate is higher when using the apparatus of the present invention.

As described above, the present invention has the advantage that not only is the efficiency of film formation high (but also the characteristics of the thin film are improved).
The etching speed of the etching equipment is also improved compared to the conventional equipment, and the same is true for the sputtering equipment (
Thin film formation speed is improved.

As is clear from Fig. 10.11, it is more efficient to use a frequency twice the commercial frequency than to use the commercial frequency.

The reason why high efficiency can be obtained by intermittent driving the microwave source as described above will be discussed. The plasma generation chamber 1 has a cavity resonator structure for microwave power guided thereto.

This is similar to the conventional device. However, when the microwave source 11 is driven and microwaves are introduced here, resonance occurs, but when plasma is generated by electron cyclotron resonance, the resonance conditions of the plasma generation chamber 1 change, and after that, the plasma-free state before driving changes. A completely resonant state cannot be obtained as in the case. In other words, the plasma generation chamber is designed to have cavity resonance in a plasma-free state, so if plasma is generated and this affects microwave propagation, it will not function as a cavity resonator as designed.
Therefore, this results in a decrease in plasma generation efficiency.

Therefore, when continuously driven as in the conventional device, such a state of low efficiency continues. On the other hand, in the case of intermittent driving as in the device of the present invention, the plasma generation chamber functions as a designed cavity resonator each time it is driven, resulting in high plasma generation efficiency and, as a result, high deposition and etching rates. You can get it.

On the other hand, in the case of amorphous silicon film formation, such an effect cannot be obtained, and the plasma becomes unstable. The reason is unknown. Therefore, as described above, in this case, the microwave source is continuously driven by the second power source.

As described above, according to the present invention, a highly efficient semiconductor device manufacturing apparatus having a high film formation rate and high etching rate can be obtained, and the semiconductor film formed thereby has excellent physical properties. The present invention has outstanding effects such as being usable regardless of the type.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the plasma CVD apparatus, Fig. 2 is a block diagram of the power supply of the apparatus of the present invention, Fig. 3.5 is a driving waveform diagram of the microwave source, Figs. 4 and 6 are diagrams of the microwave output waveform, FIG. 7 is a block diagram of a power supply according to another embodiment of the present invention, FIG. 8 is a driving waveform diagram of the microwave source, FIG. 9 is a diagram of the microwave output waveform, and FIGS. This is a graph showing the effect. 1... Plasma generation chamber 2... Reaction chamber 7... Waveguide 11... Microwave source 18... Power supply 181
... Three-phase AC power supply 182.184 ... Full-wave rectifier circuit 183 ... Single-phase AC power supply 185 ... Chopper circuit 19a, 19a+, 19a, 19b-.
・Switch patent Applicant: Sumitomo Metal Industries, Ltd., 1 other agent, patent attorney Noboru Kono Time → Hayabusa 5 Atsushi Mitsu S Ku Time- Heron 8 Danmi 9 Eatsu 10 Chika 11 Figure

Claims (1)

[Claims] 1. In a plasma device configured to drive a microwave generation source and guide the emitted microwaves to a plasma generation chamber to generate plasma by electron cyclotron resonance,
A plasma generation chamber having a cavity resonator structure for the microwave power guided therein, a first power source that drives the microwave source intermittently at a frequency higher than the commercial frequency, and a second power source that continuously drives the microwave with direct current. and a switching device that switches between the first and second power sources and connects them to a microwave source.