JP2004008830A - Plasma cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a burning phenomenon such as the burning or the like of an article to be treated even if a magazine is used without knowing that a part of a surface is peeled to expose the magazine and that insulating irregularity is yielded. <P>SOLUTION: A pair of counter electrodes comprising an active electrode 9 and an earth electrode 11 are provided in a chamber 3 into which a process gas is introduced, and the magazine 7 having the article 5 to be treated housed and set therein through a support member made of an insulating material is supported above the active electrode 9 to certainly ensure an insulating state between the active electrode 9 and the magazine 7. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma cleaning apparatus for cleaning an object stored and set in a magazine with plasma.
[0002]
[Prior art]
A plasma cleaning apparatus introduces a process gas into a chamber reduced in pressure from the atmospheric pressure, generates plasma between a pair of opposing active electrodes and a ground electrode, and cleans an object to be processed by the plasma. It has become.
[0003]
The plasma contains ions, radicals, and the like, which contribute to the cleaning of the object to be processed, and is currently expected as a means for replacing cleaning using a cleaning liquid that causes environmental pollution and the like.
[0004]
[Problems to be solved by the invention]
Since plasma cleaning has no adverse effect on environmental pollution, its cleaning targets are expanding to, for example, electronic components and industrial components.
[0005]
More specifically, for example, a lead frame for chip mounting is inserted and set at a predetermined interval in a magazine, and the magazine is set between an opposing active electrode and a ground electrode and on the upper surface of the active electrode. As a result, cleaning by plasma is performed.
[0006]
A magazine capable of plasma-cleaning a large number of workpieces at a time is processed by a metal plate in terms of workability, durability and cost, and the surface is surface-treated with an insulating material such as alumite.
[0007]
However, for example, when the magazines are hit against each other or another place during use, the impact peels off the surface, exposing the metal, and causing uneven insulation.
[0008]
If the magazine is used without knowing that there is uneven insulation, the plasma tends to concentrate in that region and acts strongly, resulting in a problem that burning such as burning occurs in the lead frame.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma cleaning apparatus capable of obtaining stable and uniform cleaning without causing burning or the like even when a magazine is used without knowing that insulation unevenness has occurred.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a gas is blown into a chamber provided with a pair of counter electrodes each including an active electrode connected to a power supply for plasma generation and a ground electrode grounded. In a plasma cleaning apparatus for introducing a process gas from an outlet while generating plasma by depressurizing the inside of the chamber from the atmospheric pressure, and cleaning an object to be processed in a magazine whose surface is processed into an insulating state by the plasma,
The magazine is supported via a support member made of an insulating material above the active electrode.
[0011]
Thereby, even if the magazine has uneven insulation, the support member made of an insulating material supports the active electrode in a reliable insulating state, so that the plasma concentrates on a part of the magazine that becomes an exposed portion. As a result, the burning phenomenon such as burning does not occur, and stable plasma cleaning can be performed.
[0012]
According to a second aspect of the present invention, the blow-out port for blowing the process gas is disposed over an area of a predetermined size on the inner wall surface of the chamber, and blows in a shower shape from the entire area surface to the magazine. It is characterized by putting out.
[0013]
As a result, the process gas is blown substantially horizontally and uniformly toward the magazine in the chamber, so that an ionized and radicalized atmosphere can be obtained in the magazine region without unevenness.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawing of FIG.
[0015]
FIG. 1 is a schematic explanatory diagram of the entire plasma cleaning apparatus 1.
[0016]
The entire surface of the chamber 3 of the plasma cleaning apparatus 1 is an opening / closing door (not shown). By opening the opening / closing door, the magazine 7 in which the workpiece 5 is stored and set can be taken in and out. . On the other hand, a closed state is created by closing. In the chamber 3, a plate-shaped active electrode 9 and a ground electrode 11 are formed as a pair of opposing electrodes arranged so as to face up and down. The lower active electrode 9 is supported at four points by a support leg 13 made of ceramic as an insulating material, and the upper ground electrode 11 is supported at four points by a support 15 made of ceramic.
[0017]
A high frequency is applied to the active electrode 9 by a power supply 17 for plasma generation.
[0018]
As the high frequency, an RF frequency (radio wave) of 13.56 Mz is preferable, but a microwave such as 2.45 GHz or a low frequency of less than 10 kHz may be used.
[0019]
Above the active electrode 9, the above-mentioned magazine 7 is arranged and set, and the magazine 7 is supported by a support member 19 made of an insulating material such as ceramic.
[0020]
The magazine 7 is formed in a box shape with one side opened by a metal plate, and has a surface treated to be insulated with alumite or the like. Inside, for example, a lead frame for chip mounting or the like, which is to be processed 5, is stored and set at a predetermined interval.
[0021]
The ground electrode 11 facing the active electrode 9 is connected to the inner wall surface of the chamber 3 so as to be at the ground potential.
[0022]
On the other hand, an outlet 21 for blowing out the process gas is provided on one inner peripheral wall of the chamber 3, and an exhaust port 23 is provided on the other inner peripheral wall facing the outlet 21.
[0023]
The outlet 21 is provided with a large number of small-diameter holes over a region of a predetermined size, and a process gas is fed from a process supply unit (not shown) via a supply pipe 25. As a result, the process gas can be blown out from the entire region toward the magazine 7 in a substantially horizontal direction in a shower shape.
[0024]
The supply pipe 25 has a valve 27 for the process gas, and the supply or cutoff of the process gas can be controlled by opening or closing the valve 27 for the process gas.
[0025]
As the process gas, oxygen, argon, nitrogen, hydrogen, or the like may be used, or a mixed gas obtained by combining them may be used.
[0026]
The exhaust port 23 is connected to and connected to a vacuum pump (not shown) through an exhaust pipe 29, and the pressure in the chamber 3 is reduced from the atmospheric pressure by opening a vacuum pump valve 31 provided in the exhaust pipe 29. A predetermined vacuum state is created.
[0027]
The operation of the plasma cleaning apparatus 1 configured as described above will be described. First, the vacuum pump valve 31 is opened, and a vacuum pump (not shown) is operated to create a vacuum state in which the pressure in the chamber 3 is reduced from the atmospheric pressure. When the degree of vacuum reaches the set value, the process gas is blown from the outlet 21.
[0028]
Subsequently, by applying a high frequency of 13.56 MHz to the active electrode 9, a discharge occurs between the active electrode 9 and the negative electrode 11 to generate plasma.
[0029]
At this time, the process gas in the plasma blown out from the blow-out port 21 is blown out almost horizontally to the magazine 7 in a shower shape, so that it is almost uniformly ionized and radicalized without unevenness without causing dark and light. The resulting atmosphere is obtained, and at the same time, they act on the surface of the workpiece 5 such as a lead frame housed and set in the magazine 7 to remove dirt.
[0030]
At the time of this plasma cleaning step, even when the magazine 7 was used without knowing that the insulating material on the surface was peeled off and a part of the metal was exposed and there was insulation unevenness, the support member 19 reliably insulated the active electrode 9 from the active electrode 9. Since the supporting state is ensured, the problem that the plasma concentrates on the exposed portion is eliminated, and the burning phenomenon such as burning of the workpiece 5 can be prevented.
[0031]
【The invention's effect】
As described above, according to the first aspect of the present invention, even when a magazine having a part of metal exposed and having uneven insulation is used without knowing it, the magazine is supported above the active electrode in a reliable insulating state. Therefore, concentration of plasma on the exposed portion can be reliably avoided. As a result, a burning phenomenon such as burning of the object can be prevented beforehand, and stable plasma cleaning can be performed.
[0032]
According to the second aspect of the present invention, since the process gas can be blown out almost uniformly over a wide area, the process gas in the plasma can be uniformly ionized and radicalized in the magazine area.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an entire plasma cleaning apparatus according to the present invention.
[Explanation of symbols]
3 Chamber 5 Workpiece 7 Magazine 9 Active electrode 11 Earth electrode 17 Plasma generation power supply 19 Support member 21 Blow-out port

Claims (2)

A process gas is introduced from a blow-out port into a chamber provided with a pair of counter electrodes each including an active electrode connected to a power supply for plasma generation and a grounded earth electrode, and the inside of the chamber is depressurized from atmospheric pressure. In a plasma cleaning apparatus that generates plasma and cleans an object to be processed in a magazine whose surface is processed into an insulating state by the plasma,
The apparatus according to claim 1, wherein the magazine is supported above the active electrode via a supporting member made of an insulating material. 2. The plasma cleaning apparatus according to claim 1, wherein the outlet for blowing out the process gas is disposed over a region of a predetermined size on the inner wall surface of the chamber, and blows out the entire surface of the chamber in a shower shape toward the magazine. apparatus.

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