JP2005032805A - Microwave plasma processing method, microwave plasma processing equipment, and its plasma head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave plasma processing method wherein leakage prevention structure is installed on the whole periphery of an outer peripheral part of a plasma head, in order to prevent microwave from leaking from a gap between the plasma head and a substrate to be treated to the outside of the equipment, and to provide microwave plasma processing equipment and its plasma head. <P>SOLUTION: When the microwave leakage prevention is performed by installing one or a plurality of the microwave leakage prevention structure bodies in the vicinity of the outer peripheral edge of the plasma head of the microwave plasma processing equipment, the microwave leakage prevention structure body is constituted of trench parts 60a, 60b, and the depth d of the trench parts is set as d=(2n-1)1/4λ where λis a free space wavelength of the microwave used in the microwave plasma processing and n is an integer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave plasma processing method, a microwave plasma processing apparatus, and a plasma head thereof used for microwave plasma processing of a substrate such as a large glass substrate or a wafer for FPD (flat panel display).
[0002]
[Prior art]
Conventionally, for example, in a microwave plasma CVD processing apparatus for a substrate such as a large glass substrate for FPD or a wafer, the microwave plasma CVD processing apparatus is also maintained in a predetermined vacuum state through a load lock chamber maintained in a vacuum state. A substrate to be subjected to plasma CVD processing was carried into the processing chamber and a predetermined batch processing was performed in a single wafer type. Therefore, each time the substrate is loaded into or unloaded from the processing chamber, the processing chamber must be evacuated and opened to the atmosphere. Especially when a plurality of different processing is performed on the substrate, each processing is isolated. In addition, it was necessary to carry out batch processing while moving through multiple spaces (processing chambers). Therefore, the CVD process for the substrate cannot be performed continuously, and an expensive vacuum processing means is required.
[0003]
Thus, a technique has been developed that eliminates the need for such a vacuum processing means and performs plasma CVD processing continuously in-line at atmospheric pressure. In this atmospheric pressure plasma CVD technique, a plasma technique that operates at atmospheric pressure without using a vacuum is used, and a workpiece such as a wafer is continuously subjected to CVD, etching, and ashing. Further, in this atmospheric pressure plasma technology, a wafer is placed on a circulating wafer transfer device such as a belt conveyor, and different processes are performed by a plurality of atmospheric pressure plasma devices in a flow production system.
[0004]
Further, a linear plasma is formed using microwaves, and the relative position between the object to be processed (for example, a glass substrate) and the plasma is moved while the surface of the object to be processed is kept horizontal to the linear plasma. A plasma processing apparatus (for example, a CVD apparatus) that performs surface processing of a workpiece has been proposed (see Patent Document 1).
[0005]
Usually, in this type of apparatus using microwaves, in order to prevent leakage of electromagnetic waves from a microwave generation source, for example, in a microwave oven, a flange of a connecting portion with a waveguide is referred to as a choke groove. Means for preventing leakage of electromagnetic waves is provided.
[0006]
In addition, using a labyrinth structure, for example, a device for preventing leakage of a fluid such as process gas is widely used in a shaft seal device of an apparatus (see Patent Document 2).
[0007]
Further, in the plasma processing apparatus, a labyrinth seal portion is formed on the outer periphery of the plasma generation portion, an inert gas is supplied between the labyrinth seal portion and the substrate to be processed, and waste gas after processing leaks to the atmosphere. Some of them were prevented from being released (see Patent Document 3).
[Patent Document 1]
JP 2001-93871 A (paragraphs [0078], [0079] and FIG. 8)
[Patent Document 2]
Japanese Unexamined Patent Publication No. 2000-329097 ([Summary] and FIG. 1)
[Patent Document 3]
JP 2003-51490 A ([Summary] and FIG. 2)
[0008]
[Problems to be solved by the invention]
However, in such a conventional plasma processing apparatus, although the electrodes are disposed in the plasma processing chamber and a large amount of microwaves are emitted and diffused therefrom, the microwaves are accumulated in the plasma processing chamber. Therefore, effective microwave leakage prevention means has not been adopted.
[0009]
For this reason, microwaves easily leak from the plasma head of the plasma processing apparatus, and particularly in an apparatus that performs different film forming processes in parallel with a plurality of plasma heads, it leaks to another adjacent plasma head. The microwaves interfered with each other, making it impossible to perform a desired film formation process, and causing a safety problem for workers.
[0010]
Therefore, the present invention has been made in view of the problems of the conventional plasma processing apparatus as described above, so that the microwave does not leak out of the apparatus through the gap between the plasma head and the substrate to be processed. It is an object of the present invention to provide a microwave plasma processing method, a microwave plasma processing apparatus, and a plasma head thereof, in which a leakage prevention structure is provided on the outer peripheral edge of the entire outer periphery.
[0011]
[Means for Solving the Problems]
A microwave plasma processing method, a microwave plasma processing apparatus, and a plasma head thereof according to the present invention include one or a plurality of microwave leakage prevention structures in the vicinity of an outer peripheral edge of the plasma head of the plasma processing apparatus facing a substrate to be processed. When microwave leakage prevention is provided by providing a body, the microwave leakage prevention structure is composed of a groove portion, and the depth d of the groove portion is
d = (2n−1) 1 / 4λ
Here, λ is the free space wavelength of the microwave used for the microwave plasma processing, and n is an integer.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a microwave plasma processing method, a microwave plasma processing apparatus, and a plasma head thereof according to the present invention will be described below in detail with reference to the accompanying drawings.
[0013]
Microwave plasma processing method and apparatus First, as shown in Fig. 1 and Fig. 2, a microwave plasma CVD apparatus (hereinafter referred to as "CVD apparatus of the present invention") 1 according to an embodiment of the present invention. The substrate G (for example, a glass substrate) is loaded into the load lock module 2 from the platform 6a or 6b, passed through the transfer module 3 by the transfer arm 2a, and then transferred into the process module 4 by the robot arm 3a. 5, the plasma CVD process is performed in-line on the substrate G in the presence of the plasma 2. In particular, as will be described later (see FIG. 3), the plasma head 5 has one or several of the same kind to which different deposition gases can be applied so that a plurality of different deposition processes can be performed. It is composed of juxtaposed and clustered plasma heads.
[0014]
Here, the substrate G is transferred from the transfer module 3 by the robot arm 3a, and placed on the substrate stage 9a disposed in the endless substrate transport mechanism 9 that is guided and circulated in the process module 4 by the guide roll 9b. While being fixed by an electrostatic chuck (not shown) or the like and moving in the process module 4, the plasma processing is performed by the plasma head 5, and the substrate G after the CVD process is detached from the substrate stage 9 a and The substrate stage 9 a that has been transported from the end to the next processing step and has become empty returns to the start end of the process module 4 by the endless substrate transport mechanism 9. A gas unit 7 and a cooling water unit 8 are disposed below the endless substrate transport mechanism 9.
[0015]
Plasma head Further , as shown in FIG. 3, the plasma head 5 used in the CVD apparatus of the present invention has a plurality of groups, for example, three groups 5a, 5b, 5c arranged side by side through an isolation wall (not shown). Then, different film formation processes using different film formation gases are performed on the substrate G placed on the substrate stage 9a under atmospheric pressure (normal pressure). For example, the plasma head 5a performs a film formation process using Si ₃ N ₄ gas, the plasma head 5b performs a film formation process using a-Si gas, and the plasma head 5c performs a film formation process using n + Si gas. Three different deposition layers are formed on the surface of G.
[0016]
Here, the configuration of the plasma head 5 will be described in detail. As shown in FIG. 4, the plasma head 5 includes a waveguide 51, a spacer 53 disposed at the lower end thereof, and a base into which the spacer 53 is inserted. The slot plate 52 is disposed between the lower end surface of the waveguide 51 and the upper end surface of the spacer 53. The slot plate 52 includes a flange 58 and a plasma head main body 59 that holds the base flange 58. Further, a uniformizing line 54 is disposed over the spacer 53 and the base flange 58, and a plasma space 55 is formed in the lower surface space of the uniformizing line 54. Dilution gas is supplied from the dilution gas nozzle 56a to the plasma space 55, and the raw material is also formed. A raw material gas is supplied from the gas nozzle 56b, and the mixed gas thereof is supplied as a film forming gas to the surface of the substrate G placed on the substrate stage 9a to perform a predetermined film formation. .
[0017]
The microwave leaking from the plasma space 55 in the direction indicated by the arrow leaks from the groove 60, which is a leakage prevention structure formed at the outer peripheral edge of the plasma head main body 59, with the phase shifted by 90 °, and the microwave traveling straight on the other side. Will not be leaked to the outside of the plasma head 5. Here, the shape of the groove 60 may be an arbitrary shape such as a frame-shaped groove formed along the outer peripheral edge of the square plasma head main body 59.
[0018]
Microwave leakage prevention method Next, the microwave leakage prevention method of the present invention will be described. As shown in FIG. 5, a substrate G (for example, a glass substrate having a thickness of 0.63 to 0.70 mm) placed on a substrate stage 9 a that is disposed below the plasma head main body 59 and continuously moves. A gap g (about 2 mm) is formed between them to allow the substrate G to move. And if a leak prevention means is not given from this clearance gap g, a microwave will leak. Therefore, one or several grooves 60a, 60b are formed in the thickness (depth) direction in the vicinity of the outer peripheral edge of the plasma head main body 59. The shape of the grooves 60a and 60b in plan view is preferably a frame shape extending over the entire circumference, but may be any other shape as long as it has a function of preventing microwave leakage. The dimension (depth) d of the grooves 60a and 60b in the thickness direction is set to 1 / 4λ when the free space wavelength of the microwave is λ, and is an integer n (odd) times (1, 3, 5, 7). , ...). d = (2n-1) 1 / 4λ. Further, the width w of the grooves 60a, 60b may be an appropriate dimension.
[0019]
Here, the principle of the microwave leakage prevention method of the present invention will be described. As shown in FIG. 7, among the microwaves leaked from the plasma space of the plasma head, the micros that have entered the groove 60 formed in the plasma head main body 59 are shown. The wave a is 90 ° (phase converted) at the bottom of the groove 60 and leaks from the outlet of the groove 60. Here, the microwave b leaked from the plasma space and travels straight, the phase difference cancels out in the vicinity of the previous microwave a and the exit of the groove 60, and the magnetic field becomes zero. Thereby, the leakage of the microwave from a plasma head is prevented.
[0020]
According to the calculation results of the present inventors, as shown in FIG. 8, when two grooves 60a and 60b are juxtaposed at a predetermined interval in the leakage direction of microwaves, transmission of microwaves from the plasma head is performed. It was found that when the leakage rate is 0.0% and one groove 60a is provided, the transmission leakage rate can be maintained at 0.03 to 0.06%.
[0021]
【The invention's effect】
According to the microwave plasma processing method, the microwave plasma processing apparatus and the plasma head of the present invention, the leakage of the microwave from the plasma head of the microwave plasma processing apparatus is optimized by the structure of the leakage prevention groove. It can be almost completely prevented.
[0022]
As a result, microwaves from other plasma heads do not interfere with adjacent plasma heads, and a predetermined film forming process can be performed, and work safety can be sufficiently secured.
[Brief description of the drawings]
FIG. 1 is a front view showing a conceptual configuration of a microwave plasma CVD apparatus which is an embodiment of a microwave plasma processing apparatus of the present invention.
FIG. 2 is a plan view of the microwave plasma CVD apparatus shown in FIG.
FIG. 3 is a perspective view of an apparatus in which three plasma heads used in the microwave plasma CVD apparatus shown in FIG. 1 are clustered in parallel.
4 is a longitudinal sectional view of a plasma head used in the microwave plasma CVD apparatus shown in FIG.
5 is an enlarged longitudinal sectional view of a microwave leakage prevention portion of the plasma head shown in FIG.
6 is a plan view of the plasma head shown in FIG. 4 in which two microwave leakage prevention grooves are formed in a frame shape. FIG.
FIG. 7 shows a microwave plasma processing method according to the present invention in which a microwave diffracted from a groove formed in a plasma head and a microwave leaked from a plasma space cancel each other, the magnetic field becomes zero, and the microwave leaks. The conceptual diagram which shows the principle by which the prevention is prevented.
8 is a conceptual perspective view of an apparatus in which two microwave leakage prevention grooves are provided in the plasma head shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Microwave plasma CVD apparatus 2 Load lock module 3 Transfer module 4 Process module 5 Plasma head 6 Substrate carrying-in platform 7 Gas unit 8 Cooling water unit 9a Substrate stage 51 Waveguide 52 Slot plate 53 Spacer 54 Uniform line 55 Plasma Space 56a Dilution gas nozzle 56b Raw material gas nozzles 57a, 57b Gas exhaust pipe 58 Base flange 59 Plasma head body 60 Microwave leakage prevention structure

Claims (10)

A microwave plasma processing method, wherein one or a plurality of microwave leakage prevention structures are provided in the vicinity of an outer peripheral edge of a plasma head of a microwave plasma processing apparatus facing a substrate to be processed, and the microwave leakage prevention structure Is formed from a groove, and the depth d of the groove is
d = (2n−1) 1 / 4λ
Here, λ: a microwave free space wavelength used for microwave plasma processing, n: an integer, characterized in that the microwave plasma processing method. The microwave plasma processing method according to claim 1, wherein the microwave plasma processing method is a microwave plasma CVD processing method. In the microwave plasma processing apparatus, a microwave leakage prevention structure including one or a plurality of grooves is provided in the vicinity of the outer peripheral edge of the plasma head of the microwave plasma processing apparatus facing the substrate to be processed, and the depth of the grooves d
d = (2n−1) 1 / 4λ
Here, λ: a microwave free space wavelength used for the microwave plasma processing, n: an integer, a microwave plasma processing apparatus. The microwave plasma processing apparatus according to claim 3, wherein the shape of the groove in plan view is a rectangular continuous frame shape. 5. The microwave plasma processing apparatus according to claim 3, wherein the groove is formed in a multiple manner in order from the inside. The microwave plasma processing apparatus according to any one of claims 3 to 5, wherein the microwave plasma processing apparatus is a microwave plasma CVD apparatus. A microwave leakage prevention structure including one or a plurality of grooves is provided in the vicinity of the outer peripheral edge of the plasma head of the microwave plasma processing apparatus facing the substrate to be processed.
d = (2n−1) 1 / 4λ
Here, λ: a microwave free space wavelength used for microwave plasma processing, n: an integer, a plasma head. The plasma head according to claim 7, wherein the shape of the groove in plan view is a rectangular continuous frame shape. 9. The plasma head according to claim 7, wherein the groove portion is formed in multiples in order from the inside. The plasma head according to claim 7, wherein the microwave plasma processing apparatus is a microwave plasma CVD apparatus.

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