JP2000323297A - Vhf plasma producing electrode device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a uniform plasma with large area even if VHF(very high frequency) voltage is applied. SOLUTION: Two linear electrodes 2, 3 are arranged in meandering form, and a first power source 4 and a second power source 6 are connected to each of their ends. The phase of high frequency voltage applied to one electrode 2 with the first power source 4 and that of high frequency voltage applied to the other electrode 3 with the second power source 6 are shifted by 180 deg. with a phase control means 8. A synthesized waveform is made flat, and the electric field intensity in the vicinity of the electrodes is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VHF plasma generating electrode device used for high-speed film formation, high-speed etching, and the like.

[0002]

2. Description of the Related Art A plasma generation apparatus generates a plasma by applying a high-frequency voltage to an electrode, and makes active species such as neutral and ions incident on an object such as a substrate or a wafer to form a film. It performs etching and the like.

Conventionally, a parallel plate type electrode has been used as an electrode for plasma generation. However, in the case of a parallel plate type electrode, it becomes difficult to generate a large area and uniform plasma as the frequency increases. Therefore, ladder (ladder) type electrodes have been used instead of parallel plate type electrodes. According to the ladder-type electrode, it is possible to generate a large-area and uniform plasma in a frequency range up to about several tens of MHz.

[0004]

In a plasma generating apparatus, as the frequency is increased, (1) the plasma density is increased, and high-speed film formation and high-speed etching can be performed.
(2) Since the energy of ions incident on the object is reduced, there is an advantage that damage during processing is small, and higher quality film formation and etching can be performed.

However, the ladder type electrode has a frequency of 100 MHz.
Very high frequency (VHF, VeryHigh Freq)
When a voltage is applied, (1) the electric field intensity is increased at the power supply point of the electrode, and as a result, the plasma is locally increased at that portion, so that the plasma density becomes non-uniform. Due to the shortening, the potential distribution on the electrode due to the standing wave cannot be ignored, resulting in a problem that the plasma density becomes non-uniform.

[0006] Accordingly, the present invention relates to VHF (ultra high frequency).
It is an object of the present invention to provide a VHF plasma generating electrode device capable of generating a uniform plasma over a large area even when the voltage is applied.

[0007]

According to a first aspect of the present invention, there is provided a linear electrode, and a first power supply and a second power supply for applying a high-frequency voltage to the electrode. By shifting the phase of the electrodes by the phase control means, the electric field intensity generated by the first power supply and the electric field intensity generated by the second power supply are combined to generate a flat electric field intensity.

According to a second aspect of the present invention, there is provided an even number of the linear electrodes, and these electrodes are arranged in parallel with each other, and the first power supply and the second power supply are connected to each electrode. .

According to a third aspect of the present invention, the even-numbered electrodes are arranged in a meandering manner.

According to a fourth aspect of the present invention, the even-numbered electrodes are arranged in a comb shape.

According to a fifth aspect of the present invention, the first power source and the second power source are connected to both ends of the linear electrode.

According to the first to fifth aspects of the present invention, when an ultra-high frequency voltage is applied to the linear electrode by the first power supply and the second power supply, the electric field intensity generated by the first power supply and the second power supply A flat electric field intensity is generated by combining the electric field intensity generated by the power supply. Therefore, uniform plasma can be generated even in a large area.

[0013]

(Embodiment 1) FIG. 1 is a plan view of a VHF plasma generating electrode device according to Embodiment 1 of the present invention, and FIGS. 2 (a), (b) and (c) are the same. FIG. 3 is a graph showing the electric field intensity near the electrode of the VHF plasma generation electrode device. FIG. 3 is a configuration diagram of a plasma generation device using the VHF plasma generation electrode device.

In FIG. 1, a VHF plasma generating electrode device 1 is formed by bending two linear electrodes 2 and 3 in a meandering shape in parallel. Both ends of each of the electrodes 2 and 3 are connected to a first power supply 4 and a first grounding unit 5, respectively, and a second power supply 6 and a second grounding unit 7, respectively. The first power supply 4 and the second power supply 6
A high-frequency, high-strength voltage is applied to one electrode 2 and the other electrode 3 respectively. Further, the first power supply 4 and the second power supply 6 are connected to the phase control means 8. The phase control means 8 determines that the first power supply 4 and the second power supply 6
The first power supply 4 and the second power supply 6 are controlled so as to apply a voltage shifted by 80 °.

FIG. 2A shows the intensity (V / m) of the electric field generated near the electrode 2 when a high-frequency high-voltage is applied to one electrode 2 by the first power supply 4. I have.
FIG. 2B shows the intensity (V / m) of the electric field generated near the electrode 3 when a high-frequency high-voltage is applied to the other electrode 3 by the second electrode 6. FIG.
The waveforms shown in FIGS. 2A and 2B are shifted by 180 ° by the phase control means 8.

FIG. 2C shows a waveform of a synthesized wave obtained by synthesizing the waveforms of FIGS. 2A and 2B. By shifting the phase by 180 ° as described above, the composite wave becomes a flat waveform, and thus the electric field intensity near the electrode becomes uniform.

FIG. 3 shows an example of a plasma generating apparatus using the VHF plasma generating electrode device 1. In the figure, reference numeral 10 denotes a chamber in which a heating unit 11 is provided at the center. Reference numeral 12 denotes an object to be processed by plasma (film formation, etching, etc.), for example, a substrate or a wafer. The VHF plasma generation electrode device 1 is disposed at a position facing the object 12, and a gas supply unit 13 for generating a gas such as monosilane gas is disposed on a side portion thereof. 14 is a pump for vacuum suction of the inside of the chamber 10, and 15 is a valve.

In FIG. 3, after the inside of the chamber 10 is evacuated by a pump 14, gas is supplied from a gas supply unit 13, and the electrodes 2, 3 of the VHF plasma generation electrode device 1 are supplied.
, A high-frequency high-voltage is applied by the first power supply 4 and the second power supply 6. Then, a flat electric field as shown in FIG. 2C is generated, and a spatially uniform plasma is generated, so that the object 12 can be uniformly processed.

Embodiment 2 FIG. 4 is a plan view of a VHF plasma generation electrode device according to Embodiment 2 of the present invention. In the VHF plasma generation electrode device 21, a first power supply 4 and a second power supply 6 are connected to both ends of one linear electrode 22. A first power supply 4 and a second power supply 6
Are connected to the phase control means 8.

When a high-frequency high-strength voltage is applied to the electrode 22 by the first power supply 4, an electric field having the same waveform as that shown in FIG. 2A is generated, and when a high-frequency high-strength voltage is applied by the second power supply 6. An electric field having a waveform similar to that of FIG.
The composite wave shown in (c) is obtained. Therefore, the second embodiment has the same operation and effect as the first embodiment.

(Embodiment 3) FIG. 5 is a plan view of a VHF plasma generating electrode device according to Embodiment 3 of the present invention. The electrode 3 of the VHF plasma generation electrode device 31
The combs 2 and 33 are formed in a comb shape, and are disposed so as to mesh with each other so as to be parallel to each other. Each electrode 3
A first power supply 4 and a second power supply 6 are connected to the power supplies 2 and 33, respectively. The first power supply 4 and the second power supply 6 are connected to a phase control means 8.

When a high-frequency high-voltage is applied to the electrode 22 by the first power supply 4, an electric field having the same waveform as that shown in FIG. 2A is generated, and when a high-frequency high-voltage is applied by the second power supply 6. An electric field having a waveform similar to that of FIG.
The composite wave shown in (c) is obtained. Therefore, the second embodiment has the same operation and effect as the first embodiment.

As described above, the present invention can be variously changed in design. In addition to the above-described embodiments, preferably, two or more linear electrodes are provided, and an even number is provided. May be canceled to obtain a flat composite wave.

[0024]

As described above, according to the present invention, V
Even if an HF (ultra-high frequency) voltage is applied, a large area and uniform plasma can be generated.

[Brief description of the drawings]

FIG. 1 is a plan view of a VHF plasma generation electrode device according to a first embodiment of the present invention.

FIG. 2 is a graph showing the electric field intensity near the electrode of the VHF plasma generation electrode device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a plasma generation device using the VHF plasma generation electrode device according to the first embodiment of the present invention;

FIG. 4 is a plan view of a VHF plasma generation electrode device according to a second embodiment of the present invention.

FIG. 5 is a plan view of a VHF plasma generation electrode device according to a third embodiment of the present invention.

[Explanation of symbols]

 1,21,31 VHF plasma generation electrode device 2,3,22,32,33 electrode 4 first power source 6 second power source 8 phase control means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F004 AA01 BA06 BB13 CA09 5F045 AA08 BB01 EH01 EH04 EH14 EH19

Claims (5)

[Claims] 1. A linear electrode, and a first power supply and a second power supply for applying a high-frequency voltage to the electrode, wherein the phase of the first electrode and the second electrode is shifted by phase control means. Wherein the electric field intensity generated by the first power supply and the electric field intensity generated by the second power supply are combined to generate a flat electric field intensity. 2. An even number of the linear electrodes, wherein the electrodes are arranged in parallel with each other, and the first power supply and the second power supply are connected to each of the electrodes. The electrode device for generating VHF plasma according to claim 1. 3. The electrode device for VHF plasma generation according to claim 2, wherein said even number of electrodes are arranged in a meandering manner. 4. The VHF plasma generating electrode device according to claim 2, wherein said even number of electrodes are arranged in a comb-like shape. 5. The VHF plasma generating electrode device according to claim 1, wherein said first power source and said second power source are connected to both ends of said linear electrode.