JP2002343773A - Method and device for plasma processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for plasma processing which can actualize highly uniform plasma processing by reducing the partiality of a distribution of plasma. SOLUTION: By the plasma processing method, a substrate 11 is processed by generating the plasma by applying a high-frequency voltage to 1st coil or antenna 6, and then an electromagnetic wave is introduced into a vacuum container 1 through a dielectric plate 2. The high-frequency voltage is applied to the 1st coil or antenna 6 an a 2nd coil or an antenna 7 arranged coaxially between it and the dielectric plate 2, and the plasma density near the center part of the substrate 11 to be processed which has low plasma density is locally improved by the 2nd coil or antenna 7, so that the entire surface of the substrate 11 can uniformly be processed with the plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plasma processing such as dry etching, and more particularly to a high-frequency induction type plasma processing method and apparatus.

[0002]

2. Description of the Related Art In recent years, in response to the miniaturization of semiconductor devices and liquid crystal driving devices, it has become possible to realize processing with a high aspect ratio in dry etching technology.
In the D technology, realization of high aspect ratio burying is required, and therefore, plasma processing in a high vacuum is required.

For example, in the case of dry etching, when high-density plasma is generated in a high vacuum, the probability that ions collide with neutral gas particles and the like in an ion sheath formed on the surface of a substrate to be processed is reduced. Since the directionality of ions is aligned toward the substrate to be processed, and the ionization degree is high, the ratio of the incident particle flux of ions to the neutral radical reaching the substrate to be processed increases. Therefore, the etching anisotropy is enhanced, and processing with a high aspect ratio becomes possible.

As one of the plasma processing apparatuses capable of generating high-density plasma in a high vacuum, an electromagnetic wave is introduced into a vacuum container by applying a high-frequency voltage to a coil or an antenna to generate plasma. There is a high frequency induction type plasma processing apparatus. This type of plasma processing apparatus generates a high-frequency magnetic field in a vacuum vessel, generates an induction magnetic field in the vacuum vessel by the high-frequency magnetic field, accelerates electrons, and generates plasma. For example, high-density plasma can be generated even in a high vacuum, and a sufficient processing speed can be obtained.

An example of a conventional high frequency induction type plasma processing apparatus will be described with reference to FIG. In FIG. 4, the gas or gas is introduced into the vacuum vessel 21 by the gas introducing means 30 and the gas is exhausted by the exhaust means 24 to keep the inside of the vacuum vessel 21 at an appropriate pressure. When high-frequency power is applied by the high-frequency power source 22 for the antenna, an electromagnetic wave is introduced into the vacuum vessel 21 through the dielectric plate 28 to generate plasma, and the substrate 26 on the electrode 25 is etched, deposited, and surface-etched. Plasma treatment such as reforming can be performed. At this time, the electrode 2
The ion energy reaching the substrate 26 to be processed can be controlled by applying a high-frequency voltage to the substrate 5 from the electrode high-frequency power supply 27. Reference numeral 29 denotes a heating unit for heating the dielectric plate 28 in order to prevent reaction products from adhering to the dielectric plate 28.

[0006]

However, in recent years,
With the miniaturization of devices, more uniform plasma processing has been required. In particular, for liquid crystal applications, plasma processing over a wide range and high uniformity has been required due to an increase in the size of the substrate to be processed.

However, in the conventional method shown in FIG.
Since a round donut-shaped plasma is excited in the vacuum vessel 21, the plasma density often drops at the central portion and the outer peripheral portion of the substrate 26 to be processed, and the distribution of the plasma density tends to be biased, resulting in highly uniform plasma processing. There is a problem that can not be.

Hitherto, in order to control the bias of the plasma, there have been proposed improvement methods such as adjusting a gas supply method and installing a member for controlling the plasma in the vacuum vessel 21. But it was not enough.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a plasma processing method and apparatus capable of reducing bias in plasma distribution and realizing highly uniform plasma processing.

[0010]

According to the plasma processing method of the present invention, plasma is generated by applying a high-frequency voltage to a coil or an antenna, and introducing an electromagnetic wave into a vacuum vessel through a dielectric plate to process a substrate. A high-frequency voltage is applied to a coil or an antenna and a second coil or an antenna coaxially disposed between the coil and the antenna and a dielectric plate. The plasma density in the vicinity of the central portion of the substrate to be processed having a low density can be locally improved, uniform plasma can be obtained over the entire surface of the substrate to be processed, and highly uniform plasma processing can be performed.

When the position of the second coil or the antenna in the axial direction is adjusted, the plasma density near the center of the substrate having a low plasma density can be locally increased in accordance with the degree.

When the shape of the second coil or the antenna is adjusted, the diameter and the number of turns in the horizontal direction are changed, so that the plasma density in the vicinity of the central portion of the substrate having a low plasma density can be changed according to the degree. Can be improved locally.

Further, the plasma processing apparatus of the present invention comprises a high-frequency power supply, a coil or an antenna to which a high-frequency voltage is applied from the high-frequency power supply, and a vacuum vessel having a wall facing the coil or the antenna formed of a dielectric plate. An electrode disposed in the vacuum vessel so as to place the substrate to be processed, and a second coil or a second coil which is disposed coaxially with the coil or antenna and between the dielectric plate and to which a high frequency voltage is applied from a high frequency power supply. An antenna is provided, and the effect of the present invention can be achieved by implementing the method of the present invention.

Further, by providing position adjusting means for adjusting the position of the second coil or antenna in the axial direction, and by providing shape adjusting means for adjusting the shape of the second coil or antenna, the above-mentioned functions and effects can be obtained. To play.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plasma processing apparatus according to the present invention will be described below with reference to FIGS.

(First Embodiment) A plasma processing apparatus according to a first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a vacuum vessel, 2 denotes a dielectric plate arranged so as to constitute a ceiling wall surface, and 3 denotes a heating means for heating the dielectric plate 2 to prevent reaction products from adhering. It is. 4 is an exhaust means for evacuating the vacuum vessel 1;
Reference numeral 5 denotes gas introduction means for introducing an appropriate gas into the vacuum vessel 1. Reference numeral 6 denotes a first coil or antenna disposed on an upper portion of the dielectric plate 2 of the vacuum vessel 1 so as to cover substantially the entire surface with its center as an axis, and 7 denotes a first coil or antenna 6.
Between the central portion of the substrate and the dielectric plate 2 and coaxial therewith.
The high-frequency power source 8 for the coil or the antenna is connected to the core of the first and second coils or the antennas 6 and 7. Reference numeral 9 denotes an electrode disposed at a lower portion in the vacuum vessel 1, and a high frequency power supply 10 for the electrode is connected to the electrode. The substrate to be processed 11 is placed on the electrode 9.

In the above configuration, while the interior of the vacuum vessel 1 is evacuated by the exhaust means 4, an appropriate gas is introduced by the gas introduction means 5 to maintain the interior of the vacuum vessel 1 at an appropriate pressure, and
When high-frequency power is applied to the second coil or antennas 6 and 7 by a high-frequency power source 8 for coils or antennas, electromagnetic waves are introduced into the vacuum vessel 1 through the dielectric plate 2 to generate plasma, and plasma is generated on the electrodes 9. Can be subjected to plasma processing such as etching, deposition, and surface modification. At this time, by applying a high-frequency voltage to the electrode 9 from the electrode high-frequency power supply 10, the ion energy reaching the substrate 11 to be processed can be controlled.

At this time, the second coil or antenna 7
Substrate 11 to be processed by the plasma excited by
By increasing the density of the first coil or antenna 6 so as to be concentrated near the outer peripheral portion, the plasma density near the outer peripheral portion of the substrate 11 to be processed can be reduced. Can be improved. As a result, highly uniform plasma can be obtained, and highly uniform plasma processing can be performed.

In the present embodiment, the second coil or antenna 7 and the first coil or antenna 6 are configured to supply power from a common high-frequency power supply 8, and the first coil or antenna 7 has this basic configuration. Alternatively, when the distribution of the power supplied to the antenna 6 and the second coil or the antenna 7 is adjusted, the impedance may be adjusted by adding a capacitor, a coil, or the like to the application section of the second coil or the antenna 7. It is effective to do. Further, power may be supplied to the first coil or antenna 6 and the second coil or antenna 7 from separate high-frequency power sources 8.

(Second Embodiment) Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and only different points will be described.

In FIG. 2, there is provided a position adjusting means 12 for vertically moving the second coil or the antenna 7 up and down.

In the present embodiment, the second coil or antenna is adjusted by the position adjusting means 12 in accordance with the result of the plasma processing or the result of the measurement of the plasma density distribution by a measuring instrument (not shown) installed in the vacuum vessel 1. By adjusting the vertical position of 7, the plasma density in the vicinity of the central portion of substrate 11 can be adjusted, and the uniformity of processing of substrate 11 can be easily improved.

(Third Embodiment) Next, a plasma processing apparatus according to a third embodiment of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and only different points will be described.

In FIG. 3, a shape adjusting means 1 for adjusting the shape of the second coil or the antenna 7 such as the outer diameter and the number of turns.
3 are provided. As a specific configuration of the shape adjusting unit 13, for example, the second coil or the antenna 7 is configured by an elastic plate such as a spring plate, and is movable along a spiral guide groove formed in the support plate 14. It can be configured by disposing, and disposing a winding mechanism 15 at the center part capable of winding and unwinding the elastic plate.

In this embodiment, the second coil or the antenna 7 is adjusted by the shape adjusting means 13 in accordance with the result of the plasma processing or the result of the measurement of the plasma density distribution by a measuring instrument (not shown) installed in the vacuum vessel 1. By adjusting the outer diameter and the number of turns, the plasma density near the center of the substrate 11 can be adjusted, and the uniformity of the processing of the substrate 11 can be easily improved.

[0027]

According to the plasma processing method and apparatus of the present invention, as described above, a high-frequency voltage is applied to the coil or antenna and the second coil or antenna coaxially disposed between the coil or antenna and the dielectric plate. The second coil or the antenna can locally improve the plasma density near the central portion of the substrate to be processed having a low plasma density, so that uniform plasma can be obtained over the entire surface of the substrate to be processed. ,
Highly uniform plasma treatment can be performed.

When the position of the second coil or the antenna in the axial direction is adjusted, the plasma density in the vicinity of the central portion of the substrate having a low plasma density can be locally increased in accordance with the degree.

When the shape of the second coil or the antenna is adjusted, the diameter and the number of turns in the horizontal direction are changed, so that the plasma density in the vicinity of the central portion of the substrate having a low plasma density is changed according to the degree. Can be improved locally.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a plasma processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a conventional plasma processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Dielectric plate 6 1st coil or antenna 7 2nd coil or antenna 8 High frequency power supply 9 Electrode 11 Substrate to be processed 12 Position adjustment means 13 Shape adjustment means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihisa Okazaki 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 4K030 CA04 CA12 FA04 KA14 KA15 KA30 5F004 AA05 BA20 BB18 BB32 5F045 AA08 CA15 DP04 EH02 EH03 EH11

Claims (6)

[Claims] 1. A plasma processing method for applying a high-frequency voltage to a coil or an antenna and introducing an electromagnetic wave into a vacuum vessel through a dielectric plate to generate plasma to process a substrate. A high frequency voltage is applied to a second coil or an antenna disposed coaxially with a dielectric plate. 2. The plasma processing method according to claim 1, wherein the position of the second coil or the antenna in the axial direction is adjusted. 3. The plasma processing method according to claim 1, wherein the shape of the second coil or the antenna is adjusted. 4. A high-frequency power supply, a coil or an antenna to which a high-frequency voltage is applied from the high-frequency power supply, a vacuum container having a wall facing the coil or the antenna made of a dielectric plate, and a substrate to be processed mounted thereon. And a second coil or antenna disposed coaxially with the coil or antenna and between the dielectric plate and receiving a high-frequency voltage from a high-frequency power supply. Plasma processing apparatus. 5. The plasma processing apparatus according to claim 4, further comprising a position adjusting means for adjusting an axial position of the second coil or the antenna. 6. The apparatus according to claim 4, further comprising a shape adjusting means for adjusting the shape of the second coil or the antenna.
The plasma processing apparatus as described in the above.