JP2002329711A - Parallel plate type electrode plasma processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma etching processing device capable of etching fine patterns with high uniformity on, for example, the TFT portion of a large size substrate used in a liquid crystal display and the like. SOLUTION: An etching gas 13 is supplied from the top of a vacuum container 1, in which a processing substrate 3 is set, and after diffused by an auxiliary diffusing plate 21 having plural gas channels, the gas is further made uniform by an upper electrode 20 having plural gas distributing channels. Moreover, shield wall plates 22 are arranged in such a way as to surround the substrate mounting surface of a lower electrode 9, between the upper and lower electrodes, thereby stagnation of the gas and unevenness in the plasma on the processing substrate in the vacuum container can be prevented, and the uniformity of the etching speed and the film forming speed on the surface of a large substrate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus using a parallel plate type electrode, and more particularly, to an etching rate performance and a film forming rate performance in an etching or film forming process using plasma. The present invention relates to a parallel plate type electrode plasma processing apparatus having high internal uniformity.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for dry processes in manufacturing processes such as etching and film formation of LSIs for liquid crystal displays and semiconductor products, and plasma technology has been frequently used. The size of a substrate to be processed is increasing with the development of the semiconductor device. However, uniformity of the plasma technology cannot keep up with the enlargement of the substrate and the miniaturization of the pattern, and the difference in the speed of etching and film formation between the central part and the peripheral part causes unevenness in the etching and pattern width, This was a factor in reducing productivity. Further, such unevenness in etching and unevenness in pattern width cause a significant deterioration in image quality and reliability of a liquid crystal display or the like.

[0003] An etching apparatus using a plasma technique according to a conventional method will be described below as an example.

FIG. 4 shows a cross section of a processing apparatus using a conventional parallel plate type electrode. First, the processing substrate 3 transferred from the previous process into the vacuum container 1 for storing the substrate.
Is placed on a lower electrode 9 controlled at a constant temperature by cooling water 8 whose temperature has been adjusted. Next, the vacuum vessel 1
The stop valve 4 is opened, and the vacuum pump 5 is evacuated through the vacuum exhaust pipe 15, while the etching gas 13 required for etching is supplied to the vacuum vessel 1 through the gas pipe 14 by opening the gas valve 12 from the opposite side of the vacuum pump 5. Then, the vacuum vessel 1 is maintained at a constant pressure by controlling the pump exhaust capacity.

When the pressure becomes constant, high-frequency power is applied to the upper electrode 2 and the lower electrode 9 using the high-frequency power source 6,
The gas starts discharging and gas plasma is generated. In adjusting the plasma discharge, the plasma is concentrated in the region between the upper and lower electrodes by the shield wall plate 11 while adjusting the reflected wave to the minimum with respect to the high frequency output applied by the tuning circuit in the matching box 7. The aim is to stabilize the plasma and prevent its spread. The activated gas and the gas reacted with the sample are exhausted to the outside of the vacuum vessel 1 by the vacuum pump 5 through the vacuum exhaust pipe 15.

At the end of the processing, the oscillation of the high frequency power supply 6 is stopped, the plasma discharge is stopped, and the etching gas 13
Is stopped by closing the gas valve 12. After the residual gas in the vacuum vessel 1 is removed by the vacuum pump 5 via the vacuum exhaust pipe 15, the substrate is carried out to the next step.

[0007]

However, in the above-described conventional processing apparatus, as the size of the substrate to be processed increases with the increase in productivity and cost, the gas flow becomes uneven in the plane of the processing substrate. In addition, the plasma discharge also becomes non-uniform, the uniformity of the etching rate in the substrate surface deteriorates, the required line width and film thickness cannot be secured, and the etching line width is And unevenness due to differences in film thickness. In the worst case, trying to obtain a line width as designed at the center may cause the peripheral pattern to become thinner and even disappear, resulting in many problems in terms of productivity, reliability and cost. There was a problem of causing trouble.

The present invention solves the problems of the processing apparatus according to the above-described conventional method, and is used for a liquid crystal display or the like by preventing uneven line width and uneven film thickness occurring in steps such as etching and film forming processing. An object of the present invention is to provide a parallel plate type electrode plasma processing apparatus capable of obtaining a large substrate.

[0009]

In order to solve this problem, a parallel plate type electrode plasma processing apparatus according to the present invention comprises:
A vacuum container having an exhaust unit and containing a substrate on which processes such as etching and film formation are to be performed; a gas supply unit for supplying a plasma generation gas into the vacuum container; and a parallel container installed in the vacuum container. In a plasma processing apparatus including a plate-type electrode and a power supply for plasma generation, the parallel plate-type electrode includes an auxiliary electrode having a plurality of gas paths, an upper electrode having a plurality of gas dispersion channels, and the upper electrode. And a lower electrode for placing and setting the substrate placed opposite thereto, and a shield wall plate is disposed between the upper and lower electrodes so as to surround the periphery of the substrate mounting surface of the lower electrode. Is what you do.

The parallel plate type electrode comprises an upper electrode having a plurality of gas dispersion channels, and a lower electrode which is disposed opposite to the upper electrode and on which a substrate is placed and set. And a shield wall plate is disposed between the upper and lower electrodes so as to surround the periphery of the substrate mounting surface of the lower electrode.

According to the above configuration, gas stagnation on the processing substrate in the vacuum vessel and non-uniformity of plasma are prevented.
In-plane uniformity of the etching speed and the film forming speed on a large substrate can be improved.

[0012]

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

(Embodiment 1) FIG. 1 shows a cross section of a parallel plate type electrode plasma processing apparatus according to Embodiment 1 of the present invention. The same components as those in the conventional example are denoted by the same reference numerals. In FIG. 1, 1 is a vacuum vessel,
3 is a processing substrate, 4 is a stop valve, 5 is a vacuum pump,
6 is a high frequency power supply, 7 is a matching box, 8 is cooling water whose temperature is controlled, 9 is a lower electrode, 10 is an insulator, 12 is a gas valve, 13 is an etching gas, 14 is a gas pipe, 15
Is a vacuum exhaust pipe, 20 is an upper electrode having a plurality of gas dispersion channels, 21 is a diffusion auxiliary plate having a plurality of gas paths, 22 is a shield wall plate, and 23 is a shield plate fixing portion.

First, the processing substrate 3 transported from the previous process to the vacuum container 1 for accommodating the substrate is electrically insulated from the vacuum container 1 by the insulator 10 and is fixed by the cooling water 8 whose temperature is controlled. A shield plate 22 placed on the lower electrode 9 controlled at a temperature of and extending from a shield plate fixing portion 23 installed at the bottom of the vacuum vessel 1 is arranged so as to surround the lower electrode 9 and the periphery of the processing substrate 3. Have been.

Next, the vacuum vessel 1 is evacuated by a vacuum pump 5 by opening a stop valve 4 through a vacuum exhaust pipe 15 drawn out from a lower portion of the vacuum vessel. When a certain degree of vacuum is reached, a gas required for etching is supplied. Is done. The etching gas 13 is supplied from the upper part of the vacuum vessel 1 to the gas valve 12.
The gas is supplied from one location through the gas pipe 14 and the flow is divided into a number of parts by the diffusion auxiliary plate 21 having a plurality of gas paths. Then, it is supplied onto the substrate in the vacuum vessel 1.

The vacuum vessel 1 is maintained at a constant pressure by controlling the gas flow rate to be supplied and the pumping capacity, and when the pressure becomes constant, high-frequency power is applied to the upper electrode 20 and the lower electrode 9 using the high-frequency power source 6. Apply. Thereby, the gas starts discharging and gas plasma is generated. To adjust the plasma discharge, the shield wall plate 22 is used to concentrate the plasma in the region between the upper and lower electrodes while adjusting the reflected wave to a minimum with respect to the high frequency output applied by the tuning circuit in the matching box 7. The aim is to stabilize the plasma and prevent its spread.

The activated gas and the gas reacted with the sample are as follows:
The air is evacuated to the outside of the vacuum vessel 1 through the vacuum exhaust pipe 15 by the vacuum pump 5. When the processing for a predetermined time is completed, the oscillation of the high-frequency power supply 6 is stopped, and the plasma discharge is stopped. Close the gas valve 12 to stop the supply of the etching gas 13,
After the residual gas in the vacuum vessel 1 is removed by the vacuum pump 5 via the vacuum exhaust pipe 15, the substrate is carried out to the next step.

As described above, according to the first embodiment, the etching gas 1 introduced into the vacuum vessel 1 from above is used.
3 is first diffused once by the diffusion assisting plate 21 and further divided and diffused again by the upper electrode 20 to be supplied onto the substrate, so that the distribution of the etching gas is made uniform, and the processing substrate 3 and the lower electrode 9 are diffused. Wall plate 2 provided around
2 also prevents unnecessary gas diffusion,
It is possible to effectively uniform the gas on the substrate. Also, by providing the shield wall plate 22 around the lower electrode 9, the plasma is concentrated in the region between the upper and lower electrodes,
In addition, it is possible to stabilize the plasma on the substrate side and prevent the spread thereof, thereby achieving uniform etching speed over a large area.

(Embodiment 2) FIG. 2 shows a cross section of a parallel plate type electrode plasma processing apparatus according to Embodiment 2 of the present invention. The same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, 200 is the upper electrode, 220 is the shield wall plate, and 230 is the shield wall plate 2
Reference numeral 20 denotes a vertically movable mechanism.

The difference between the second embodiment and the first embodiment is that the diffusion auxiliary plate 21 is eliminated as a means for diffusing the etching gas 13 supplied from the upper part of the vacuum vessel 1.
Instead, the hole diameters of the plurality of gas dispersion channels are processed with two different dimensions on the gas inlet side and the outlet side facing the substrate, and the depth of the gas outlet side hole diameter is increased to the thickness of the upper electrode. A point that the upper electrode 200 secured at least １ ／ is provided,
Further, the shield wall plate 22 having the vertically movable mechanism 230
0 is provided, and the area surrounded by the shield wall plate 220 is larger than the dimension of the processing substrate 3 and smaller than the dimension of the lower electrode 9 so as to surround the lower electrode.

According to the second embodiment configured as described above, the upper electrode is provided with different hole diameters in the upper and lower directions, and the substrate side in the depth direction is at least の of the thickness of the upper electrode. In this way, the auxiliary diffusion plate can be removed, the mechanism becomes simple and the gas can be diverted sufficiently, and furthermore, the upper and lower mechanisms are provided on the shield wall plate so that it can be placed on the lower electrode and the plasma generation area can be made uniform. By providing the function of preventing unnecessary diffusion of gas at an optimum position, the etching speed can be further uniformed over a large area.

FIG. 3 shows the uniformity ratio of the etching speed when the area ratio between the area of the processing substrate 3 and the area of the outermost blowing section of the plurality of gas dispersion channels is changed. As is clear from FIG.
Good results were obtained in the range where the area of the outermost blown gas dispersion channel was reduced in the region 73. Furthermore, when the hole diameter on the gas outlet side of the gas dispersion channel provided in the upper electrode was changed, a good result of the uniformity ratio was obtained by setting the hole diameter in the range of 1.0 mm to 1.3 mm. .

The above-described upper electrode 20 and upper electrode 200
As a material of the diffusion assisting plate 21, a substance having resistance to impurity contamination and an etching gas in the substrate 3 is suitable. As a material of, an alloy using nickel as a main raw material or aluminum or aluminum oxide meets the conditions, and it has been confirmed from experiments that the same effect was obtained in the second embodiment.

[0024]

As described above, according to the present invention, by combining a diffusion auxiliary plate having a plurality of gas paths in an upper electrode portion and an upper electrode having a plurality of gas dispersion channels, the inside of the vacuum vessel is reduced. The flow of supplied gas is greatly improved to achieve uniformity, and furthermore, by combining a shield wall plate placed between the upper and lower electrodes, gas stagnation on the processing substrate in the vacuum vessel and non-uniformity of plasma are achieved. Thus, the in-plane uniformity of the etching speed and the film forming speed on a large substrate can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a parallel plate type electrode plasma processing apparatus according to a first embodiment of the present invention.

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

FIG. 3 is a diagram showing a uniformity ratio with respect to an area ratio between an area of a processing substrate and a region of an outermost blowing portion of a plurality of gas dispersion channels in Embodiment 2 of the present invention.

FIG. 4 is a cross-sectional view of a conventional parallel plate type electrode plasma processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vacuum container 3 Processing board 4 Stop valve 5 Vacuum pump 6 High frequency power supply 7 Matching box 8 Cooling water 9 Lower electrode 10 Insulator 12 Gas valve 13 Etching gas 14 Gas pipe 15 Vacuum exhaust pipe 20 Upper electrode having a plurality of gas dispersion channels Reference Signs List 21 Diffusion auxiliary plate having a plurality of gas passages 22 Shield wall plate 23 Shield plate fixing portion 200 Upper electrode having a gas outlet side hole diameter of at least 1/2 of the plate thickness of lower electrode 220 Upper and lower movable mechanism Shield wall plate 230 having a vertical movement mechanism of the shield wall plate

Continued on the front page F-term (reference) 4G075 AA24 AA30 BC01 BC06 CA03 CA25 DA02 EB01 EB42 EC09 EC21 FA01 FB02 4K030 EA03 EA05 FA03 KA12 KA15 KA30 KA46 LA15 LA18 5F004 AA01 BA06 BB28 BB29 5F045 AA02 E04 EB03 E05 EB03 E05 EH13

Claims (9)

[Claims] 1. A vacuum vessel having an exhaust means and accommodating a substrate on which processes such as etching and film formation are performed, gas supply means for supplying a plasma generation gas into the vacuum vessel, and In a plasma processing apparatus provided with a parallel plate type electrode and a power supply for plasma generation, the parallel plate type electrode is provided with a diffusion auxiliary plate having a plurality of gas paths, and an upper electrode having a plurality of gas dispersion channels. And a lower electrode disposed opposite to the upper electrode and placed on a substrate, and a shield wall plate is disposed between the upper and lower electrodes so as to surround the periphery of the substrate mounting surface of the lower electrode. A parallel plate electrode plasma processing apparatus. 2. A vacuum vessel having an exhaust means for accommodating a substrate on which processes such as etching and film formation are performed, gas supply means for supplying a plasma generation gas into the vacuum vessel, and In the plasma processing apparatus provided with a parallel plate type electrode and a power supply for plasma generation installed in the, the parallel plate type electrode is disposed to face the upper electrode having a plurality of gas dispersion channels and the upper electrode A lower electrode for mounting and setting the substrate, and a shield wall plate is arranged between the upper and lower electrodes so as to have a vertically movable mechanism and surround the periphery of the substrate mounting surface of the lower electrode. Parallel plate type electrode plasma processing apparatus. 3. The parallel plate type electrode plasma processing apparatus according to claim 1, wherein the upper electrode has a blowing region of the plurality of gas dispersion channels smaller than an area of a substrate to be processed. 4. The method according to claim 3, wherein the ratio of the area of the outermost blow-out area of the plurality of gas dispersion channels to the area of the substrate to be processed is in the range of 0.53 to 0.73. Parallel plate type electrode plasma processing apparatus. 5. The parallel plate type electrode plasma processing apparatus according to claim 2, wherein the upper electrode has a stepped hole having two or more kinds of hole diameters in the gas dispersion channel. 6. The parallel plate type electrode plasma according to claim 5, wherein the stepped hole has a depth of a hole diameter on the gas blowing side that is equal to or more than に 対 し て of a plate thickness of the upper electrode. Processing equipment. 7. The parallel plate type electrode plasma processing apparatus according to claim 6, wherein a diameter of the gas outlet side hole is in a range of 1.0 mm to 1.3 mm. 8. The parallel plate type electrode plasma processing apparatus according to claim 1, wherein the material of one of the diffusion auxiliary plate and the upper electrode is made of an alloy mainly composed of nickel. 9. The parallel plate type electrode plasma processing apparatus according to claim 1, wherein the material of the shield wall plate is made of an alloy mainly composed of nickel, aluminum or aluminum oxide.