JP2007237080A - Plasma cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out a quick surface treatment for any object to be treated. <P>SOLUTION: The apparatus comprises an electric field applying electrode 3 having a vertical face 9 and a horizontal down face 11 and an earth electrode 5 having a vertical face 15 facing the vertical face of the electric field applying electrode 3 and a horizontal down face 17. A process gas is flowed to the respective vertical faces 9 and 15 and the respective down faces 11 and 17 from a plasma supply port 23 and on the other hand, the vertical face 9 and the horizontal down face 11 of the electric field applying electrode 3 to which high-frequency voltage is to be applied are made to serve as planar electric discharge electrode faces for producing a plasma generation region and the generated plasma is made to hit in plane-state against the top face of an object 27 to be treated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma cleaning apparatus for performing surface treatment by applying generated plasma to a surface of an object to be processed.

  In general, plasma cleaning has recently gained a lot of attention in place of CFC cleaning processing that uses CFC, which is said to have an adverse effect on the earth. It has been used in many fields including the electronics field. Yes.

  For example, cleaning of foreign substances such as organic substances existing on the surface of the object to be processed, peeling of resist and etching, improvement of adhesion of organic film, reduction of metal oxide, film formation, plating pretreatment, coating pretreatment Used for surface treatment such as surface modification of various materials and parts.

  In the plasma cleaning process, in addition to performing the surface treatment by passing the object to be processed through the plasma gas generation passage generated by the opposing electrodes, the generated plasma is injected from the injection port onto the surface of the object to be processed. There is a type that performs surface treatment by making it.

Ions, electrons, radicals, and ultraviolet rays exist in the plasma, and surface treatment is performed by these ions acting on the surface of the workpiece.
JP 2002-72497 A

  The type that performs surface treatment by applying plasma to the surface of the object to be processed has the merit that only the necessary part can be surface treated compared to the type that performs surface treatment by passing through the plasma gas generation passage. The generated plasma is blown out into a narrow hole shape. The processing area is also a narrow hole region with a narrow width.

  This is made up of a structure in which a pair of electrodes that generate plasma are opposed to each other. For example, when performing surface treatment of an object to be processed such as a wafer having a certain surface area, Surface treatment is performed by passing under the blown-out plasma.

  The specific processing operation at this time is that plasma is applied to the end portion of the object to be processed for a certain time (second unit), and then moved slightly by the width of the long hole and plasma is applied for a certain time. Subsequently, the surface treatment is performed sequentially from the end by repeating the operation of moving slightly by the width of the long hole and applying the plasma for 1 hour. Time was required and there was a problem in terms of processing efficiency.

  In this case, it is possible to increase the processing speed to some extent by shortening the injection time per one time to which the plasma is applied, but in order to do so, it is necessary to complete the surface treatment in a short time, so a strong output plasma is required. Is done.

  For example, in the case of an object to be processed on which an electronic component is mounted, the high-power plasma has a problem that it cannot be used depending on the object to be processed, such as the possibility of damaging the electronic component.

  Accordingly, an object of the present invention is to provide a plasma cleaning apparatus capable of improving the processing speed and having versatility capable of performing surface treatment on any object to be processed.

  To achieve the above object, the present invention includes an electric field applying electrode having a vertical surface and a horizontal lower surface, and a vertical surface and a horizontal lower surface facing the vertical surface of the electric field applying electrode. Process gas supply port provided in the gas flow path formed by the vertical surface of the corresponding ground electrode, the vertical surface of the corresponding electric field applying electrode and the vertical surface of the ground electrode, and the process gas from the gas flow path toward the lower carrier And the vertical surface and the bottom surface of the one electric field application electrode are planar discharge electrode surfaces that form a planar plasma generation region from the vertical surface to the bottom surface. .

  According to the present invention, since a continuous plasma generation region can be formed on the vertical surface and the lower surface of the electric field applying electrode, the plasma generated on the upper surface of the object to be processed acts as a surface. The processing area that can be processed in a single operation is greatly expanded, and even a workpiece having a large area can quickly complete the surface processing operation.

  In addition, since a planar processing with a large processing area per time can be performed, it is possible to take a long processing time even if a weak power plasma that does not cause damage is used, and any type without any restriction. Even the object to be processed can be processed.

  According to the present invention, firstly, the distance between the lower surface of the electric field application electrode serving as the planar discharge electrode surface and the upper surface of the workpiece disposed below the lower surface is set to a dimension of 0.5 mm to 4 mm. A stable planar plasma generation region is created on the lower surface of the electric field application electrode.

  Secondly, a plurality of the pair of electric field application electrodes and ground electrodes facing each other are arranged in series along the conveyance direction of the object to be processed, and a continuous fast flow is achieved by enlarging the processing area for surface processing. The flow work is possible.

  Hereinafter, embodiments of the present invention will be specifically described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic sectional view of the entire plasma cleaning apparatus according to the present invention. The plasma cleaning apparatus 1 includes an electric field application electrode 3, a ground electrode 5 facing the electric field application electrode 3, and a process gas supply unit 7.

  The electric field applying electrode 3 is formed of a material such as aluminum into a rectangular cross section having a vertical surface 9 and a horizontal lower surface 11 and is formed in a rectangular tube shape that is long to the left and right when viewed from the front as shown in FIG.

  The vertical surface 9 and the lower surface 11 of the electric field application electrode 3 are respectively continuous planar discharge electrode surfaces, and a high frequency voltage is applied by the plasma generation power source 13. As the high frequency, a sine wave of 50 kMz to 27.12 Mz is preferable, but a pulse wave may be used.

  The ground electrode 5 is formed in a rectangular cross section having a vertical surface 15 and a horizontal lower surface 17 made of a material such as aluminum. The length and width of the ground electrode 5 are formed in the same shape as that of the electric field applying electrode 3, and are fixedly supported by the insulating support member 19 while being arranged in parallel with the electric field applying electrode 3.

  The vertical surface 15 of the ground electrode 5 faces the vertical surface 9 of the electric field applying electrode 3, and a vertical gas path 21 is formed by the vertical surfaces 9, 15 facing each other.

  The gas passage 21 is provided with a process gas supply port 23 in the upper part and a gas outlet 25 in the lower part.

  The planar discharge electrode surface of the vertical surface 9 and the planar discharge electrode surface of the lower surface 11 constituting the gas passage 21 are viewed from the front in FIG. 2, from one side wall 19a to the other side wall 19b of the support member 19. The width D is the maximum processing width for surface-treating the workpiece 27. Further, the side walls 19a and 19b on both sides function as blocking walls that prevent the process gas from escaping from both sides.

  The electric field applying electrode 3 and the ground electrode 5 are of a water cooling type in which cooling paths 29 through which cooling water flows are provided in the central portion. Plate-shaped dielectrics 31 a and 31 b made of quartz glass or ceramic are provided on the vertical surfaces 9 and 15 and the lower surfaces 11 and 17 of the electric field applying electrode 3 and the ground electrode 5, respectively. Between the dielectric 31a and the dielectric 31a provided so as to oppose each of the vertical surfaces 9 and 15, a long hole-like gas passage 21 having a narrow width when viewed from the plane is formed, so that the process gas supply port 23 The process gas passes through the gas passage 21 to obtain a flow extending in a plane from the gas outlet 25 toward the lower surfaces 11 and 17.

  The dielectrics 31a and 31b are provided to ensure stable discharge and are not necessarily required.

  On the other hand, on the lower surface 11 of the electric field applying electrode 3 provided with the dielectrics 31a and 31b and the lower portion of the lower surface 17 of the ground electrode 5, a conveying body 33 is disposed as shown by an arrow A in FIG.

  The conveyance body 33 has a set plate 37 for setting the workpieces 27 one by one on a conveyance member 35 such as a chain that is wound endlessly around a driving wheel and a driven wheel (both not shown). It is provided to rotate endlessly.

  Since the carrier 33 has a structure facing the lower surface 11 as described above, when a high frequency voltage is applied to the electric field applying electrode 3, the lower surface 11 including the vertical surface 9 of the electric field applying electrode 3 is also planar. A plasma generation region is created.

  The planar plasma generation region formed on the lower surface 11 of the electric field application electrode 3 has been found by experiment. How the plasma generation region is formed on the lower surface 11 without the ground electrode 5 facing each other like the vertical surface 9. Although it is not theoretically elucidated whether it is made or not, the lower surface 11 of the electric field applying electrode 3 is a planar discharge electrode surface like the vertical surface 9, and the carrier 33 that functions as a ground electrode is provided below. It is presumed that discharge is caused and plasma is generated by arranging them facing each other.

  In this case, the distance h from the lower surface 11 of the electric field applying electrode 3 to the upper surface of the workpiece 27 set on the upper surface of the carrier 33 is preferably between 0.5 mm and 4 mm. Preferably it is 1.5 mm. As a result, even in the actual result, stable plasma generation can be obtained in combination with the combination of the dielectrics 31b.

  On the other hand, the plasma supply port 23 is connected to and communicated with a process gas supply means 7 such as a cylinder through a supply pipe 37, and the process gas is supplied and cut off by opening or closing a control valve 39 provided in the supply pipe 37. Control is possible.

  Examples of the process gas include helium or argon gas, which can be used alone or as a mixed gas in combination.

  In this case, it is desirable to use means for combining a reaction gas such as oxygen or hydrogen in addition to helium or argon gas.

  According to the plasma cleaning processing apparatus 1 configured as described above, the process gas is fed from the process gas supply port 23, and a high-frequency voltage is applied to the electric field application electrode 3 in a state where the process gas is filled in the gas passage 21 and the lower surfaces 11 and 17. By applying, a planar plasma generation region is formed on the vertical surface 9 and the lower surface 11 side of the electric field application electrode 3.

  As a result, the upper surface of the object to be processed 27 is a surface treatment having a large processing area per time, and thus the surface treatment can be completed quickly even for the object to be processed 27 having a large area. In addition, because surface processing with a large processing area does not take a long processing time, it is possible to process even with low-power plasma, and any type of workpiece can be processed without damage. Processing can be performed.

  In this case, a plurality of pairs of electric field applying electrodes 3 and ground electrodes 5 constituting the plasma cleaning apparatus 1 may be arranged in series along the transport direction.

  As a result, the processing area for the surface processing increases along the transport direction, so that a continuous work with a fast flow can be performed, and the processing capability can be greatly improved.

The AA line expansion outline explanatory drawing of FIG. 2 of the plasma cleaning apparatus concerning this invention. The outline front view of a plasma cleaning device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Electric field application electrode 5 Ground electrode 7 Process gas supply means 9 Vertical surface of electric field application electrode 11 Lower surface of electric field application electrode 15 Vertical surface of ground electrode 17 Lower surface of ground electrode 21 Gas passage 23 Process gas supply port 25 Gas outlet 27 Covered Processed product 31a, 31b Dielectric 33 Transporter

Claims (3)

  An electric field applying electrode having a vertical surface and a horizontal lower surface; a ground electrode having a vertical surface and a horizontal lower surface facing the vertical surface of the electric field applying electrode; and a vertical surface of the corresponding electric field applying electrode. A process gas supply port provided in a gas flow path formed by a vertical surface of the ground electrode, and a gas outlet for flowing a process gas from the gas flow path toward a lower carrier, the one electric field A plasma cleaning apparatus characterized in that the vertical surface and the lower surface of the application electrode are planar discharge electrode surfaces that form a planar plasma generation region from the vertical surface to the lower surface.   The distance between the lower surface of the electric field application electrode serving as the planar discharge electrode surface and the upper surface of the workpiece to be disposed under the lower surface is set to a size of 0.5 mm to 4 mm. Item 2. The plasma cleaning apparatus according to Item 1.   2. The plasma cleaning apparatus according to claim 1, wherein a plurality of a pair of electric field applying electrodes and ground electrodes facing each other in the vertical plane are arranged in series along a conveyance direction of the object to be processed.

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