JP2011159638A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device restraining deterioration on uniformity of plasma treatment. <P>SOLUTION: The plasma treatment device includes: a treatment chamber 10 for performing plasma treatment on a substrate 20; a ground electrode 12 arranged inside the treatment chamber 10 and mounting the substrate 20 on its upper surface; an electrode plate 16 facing to the ground electrode 12 by sandwiching a plasma space 26; a high-frequency electrode 14 wherein the electrode plate 16 is electrically connected with a first primary surface of the high-frequency electrode 14 at a plasma space 26 side and a second primary surface of the high-frequency electrode 14 opposite to the first primary surface is connected with the high-frequency power supply 24; and a low-head hexagon bolt 18 wherein a thickness of a head part is at a range of 1-2 mm and the head part is made faced to the ground electrode 12 and the electrode plate 16 is fixed on the high-frequency electrode 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that performs processing using plasma generated between electrodes.

  A plasma processing apparatus having an external electrode includes a grounded ground electrode on which a substrate is placed in a processing chamber, and a high-frequency electrode having a high-frequency power source connected to the back surface exposed to the outside of the processing chamber. The surfaces of the ground electrode and the high-frequency electrode are opposed to each other. Usually, the ground electrode has a larger surface area than the high-frequency electrode. A removable electrode plate is attached to the surface of the high-frequency electrode.

  High frequency power is supplied from the back surface of the high frequency electrode, and plasma is generated between the ground electrode and the high frequency electrode. The substrate is subjected to plasma treatment by the generated plasma.

  When a normal hexagon bolt is used to attach the electrode plate to the surface of the high frequency electrode, the convenience of attaching / detaching the electrode plate is high. However, the distance between the ground electrode and the high-frequency electrode becomes non-uniform due to the head of the hexagon bolt that protrudes from the surface of the electrode plate. For this reason, the uniformity of the plasma processing is deteriorated due to the electric field concentration on the head of the hexagon bolt.

  In addition, if a countersunk bolt is used to attach the electrode plate to the surface of the high-frequency electrode, it is possible to suppress deterioration in uniformity of plasma processing. However, the countersunk bolt is tightened by inserting a tightening tool such as a screwdriver into a tightening groove such as a slot or a cross groove provided on the top surface of the head. Therefore, when attaching and detaching the electrode plate, it is difficult to apply torque to the countersunk bolt, and tightening tends to be insufficient. Further, the tightening groove may be crushed by tightening. Thus, if an electrode plate is attached to a high frequency electrode using a countersunk bolt, the convenience at the time of electrode plate attachment / detachment will be bad. Furthermore, since the through hole for inserting the countersunk bolt provided in the electrode plate cannot have sufficient play, there arises a problem that the bolt loosens due to thermal expansion of the electrode plate during plasma processing.

  An object of the present invention is to provide a plasma processing apparatus capable of suppressing deterioration in uniformity of plasma processing.

  According to aspects of the present invention, (b) a processing chamber for performing plasma processing on a substrate, (b) a ground electrode disposed inside the processing chamber and placing the substrate on the upper surface, and (c) sandwiching the plasma space The electrode plate facing the ground electrode and (d) the electrode plate is electrically connected to the first main surface on the plasma space side, and the second main surface opposite to the first main surface is connected to the high frequency power source. There is provided a plasma processing apparatus comprising: an electrode; and (e) a head having a thickness in a range of 1 mm to 2 mm, a low-head hex bolt that fixes the electrode plate to the high-frequency electrode with the head opposed to the ground electrode. .

  According to the present invention, it is possible to provide a plasma processing apparatus capable of suppressing deterioration in uniformity of plasma processing.

It is a figure which shows an example of the plasma processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of attachment of the electrode plate of the plasma processing apparatus which concerns on embodiment of this invention. It is the schematic which shows the AA cross section of the electrode plate shown in FIG. It is sectional drawing which shows the other example of the low head hexagon bolt used for attachment of the electrode plate of the plasma processing apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The following embodiments of the present invention exemplify apparatuses and methods for embodying the technical idea of the present invention. The technical idea of the present invention is based on the material and shape of component parts. The structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

  A plasma processing apparatus according to an embodiment of the present invention, for example, a plasma film forming apparatus includes a processing chamber 10, a ground electrode 12, and a high-frequency electrode 14, as shown in FIG. The processing chamber 10 is a vacuum chamber that performs plasma processing on the substrate 20 by plasma reaction. The substrate 20 to be subjected to plasma processing is placed on the ground electrode 12. In FIG. 1, the substrate 20 is directly placed on the surface of the ground electrode 12, but the substrate 20 may be placed on a plate made of a conductor or an insulator placed on the ground electrode 12.

  The ground electrode 12 is grounded. The high-frequency electrode 14 faces the upper surface of the ground electrode 12 with a plasma space 26 for generating plasma interposed therebetween. The high frequency electrode 14 is attached to the housing of the processing chamber 10 via a spacer 22.

  The high-frequency electrode 14 has a first main surface on the plasma space 26 side and a second main surface connected to the high-frequency power source 24 on the opposite side of the first main surface. An electrode plate 16 whose surface faces the plasma space 26 is attached to the first main surface of the high-frequency electrode 14. The second main surface of the high frequency electrode 14 is exposed to the outside of the processing chamber 10 and connected to the high frequency power source 24.

  The electrode plate 16 is electrically connected to the first main surface of the high-frequency electrode 14. The low-head hexagon bolt 18 has the head opposed to the ground electrode 12 and fixes the electrode plate 16 to the first main surface of the high-frequency electrode 14.

  As shown in FIG. 1, the high-frequency electrode 14 functions as a pressure partition wall together with the housing of the processing chamber 10. Therefore, it is difficult to remove the high frequency electrode 14 from the processing chamber. Therefore, the electrode plate 16 can be mechanically detached from the high frequency electrode 14 for maintenance after the plasma treatment. Although one low-head hexagon bolt 18 is shown in FIG. 1, the number of low-head hexagon bolts 18 is not limited and may be a plurality of two or more.

  The distance De between the electrode plate 16 and the ground electrode 12 shown in FIG. 1 corresponds to the thickness of the plasma space 26 and is desirably uniform in order to generate uniform plasma. However, the head of the low-head hex bolt 18 protrudes into the plasma space 26 and the distance Db from the ground electrode 12 is reduced. Therefore, the electric field concentration on the head of the low-head hex bolt 18 occurs, and the plasma becomes non-uniform. As a result, the plasma processing becomes non-uniform.

  For example, the dimensions of the high-frequency electrode 14 and the electrode plate 16 shown in FIG. 1 are about 500 mm, and the distance De between the electrode plate 16 and the ground electrode 12 is about 40 mm. As the low-head hex bolt 18, an M5 low-head bolt is used. As shown in FIGS. 2 and 3, the low-head hexagon bolt 18 is fastened to a female screw hole 19 provided in the high-frequency electrode 14 through a through-hole 17 provided in the electrode plate 16. As shown in FIG. 4, a stepped bolt may be used as the low-head hex bolt 18a.

  The M5 low head hex bolt 18 has a bolt head thickness k of about 1.5 mm. Therefore, the distance Db between the head of the low-head hexagon bolt 18 and the ground electrode 12 is a change amount of about 3.8% with respect to the distance De between the electrode plate 16 and the ground electrode 12. On the other hand, the thickness of the head of a normal hexagon bolt is about 3.5 mm, and the amount of change of the distance Db with respect to the distance De is about 8.8%. As described above, in the embodiment, the change in the interval Db is small, and it is possible to suppress the deterioration of the uniformity of the plasma processing. Further, the low-head hexagon bolt 18 can be tightened and removed with a tightening tool such as a spanner, and is convenient.

  If the thickness k is smaller than 1 mm, the strength of the low-head hex bolt 18 is reduced, and the convenience of the tightening operation is also lowered. When the thickness k exceeds 2 mm, the deterioration of the uniformity of the plasma processing becomes significant. Therefore, the thickness k of the head of the low-head hex bolt 18 is desirably in the range of 1 mm to 2 mm.

The stainless steel used for the high-frequency electrode 14 and the electrode plate 16 is SUS304 and SUS430, respectively. The thermal expansion coefficients of SUS304 and SUS430 are 16 × 10 ⁻⁶ K ⁻¹ and 11 × 10 ⁻⁶ K ⁻¹ , respectively. If the specification temperature during plasma processing is 400 ° C., the difference in the extension of the high-frequency electrode 14 and the electrode plate 16 due to thermal expansion is about 1 mm.

  The M5 low-head hexagon bolt 18 has a nominal diameter da of about 5 mm and a width across flats S of the bolt head of about 6 mm. Therefore, the diameter dt of the through hole 17 provided in the electrode plate 16 can be increased to about 6.5 mm. As a result, the thermal expansion strain during plasma processing between the high-frequency electrode 14 and the electrode plate 16 can be allowed to be about 1.5 mm, and the low-head hexagon bolt 18 can be prevented from loosening due to thermal expansion.

  As described above, the M5 low-head hex bolt 18 has been described, but the screw diameter of the low-head hex bolt 18 is not limited. As the low-head hex bolt 18, a screw diameter of M4 to M12 is desirable in consideration of convenience when the electrode plate 16 is attached and detached.

(Other embodiments)
Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  The present invention can be applied to plasma processing apparatuses used for semiconductor manufacturing, liquid crystal panel manufacturing, solar cell manufacturing, and the like.

DESCRIPTION OF SYMBOLS 10 Processing chamber 12 Ground electrode 14 High frequency electrode 16 Electrode plate 18 Low head hexagon bolt 20 Substrate 24 High frequency power supply 26 Plasma space

Claims (1)

A processing chamber for performing plasma processing on the substrate;
A ground electrode disposed inside the processing chamber and mounting the substrate on an upper surface;
An electrode plate facing the ground electrode across the plasma space;
A high-frequency electrode in which the electrode plate is electrically connected to the first main surface on the plasma space side, and a second main surface opposite to the first main surface is connected to a high-frequency power source;
A plasma processing apparatus, comprising: a head having a thickness in a range of 1 mm to 2 mm; and a low-head hex bolt that fixes the electrode plate to the high-frequency electrode with the head facing the ground electrode.

Images