JP2000340546A - Plasma treatment device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a plasma treatment device which is capable of stably and uniformly carrying out plasma treatment. SOLUTION: In a plasma treatment method, where a substrate 4 placed on an electrode 2 (2a to 2c) is subjected to plasma treatment, the substrate 4 is placed on a work mount 2c having a concave surface in a treatment chamber 6 which is hermetically sealed, the treatment chamber 6 is evacuated, then a plasma generating gas is fed into the treatment chamber 6, a high-frequency voltage is applied to the electrode 2 to produce plasma inside the chamber 6, and then the substrate 4 as a work is subjected to plasma treatment, where the substrate 4 is pressed down against the work mount 2c from above with a presser 7, so as to be curved conforming to the upper surface of the work mount 2c. By this setup, the substrate 4 can be pressed against the work mount 2c leaving no space between them, so that uniform plasma treatment free of local discharges can be realized.

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 and a plasma processing method for performing plasma processing on the surface of a plate-shaped work.

[0002]

2. Description of the Related Art Plasma treatment is used as a surface treatment method for a work such as a substrate. In this plasma processing, a surface treatment such as a cleaning treatment is performed by generating plasma in the processing chamber while a workpiece to be processed is placed on an electrode in the processing chamber. In plasma processing, it is necessary to bring the processing target into close contact with the electrode, so when targeting a plate-like work such as a conventional large substrate, the shape of the upper surface of the electrode is made a convex curved surface for the purpose of improving the adhesion. 2. Description of the Related Art Plasma processing apparatuses are known. In this plasma processing apparatus, an end of a work placed on an electrode is pressed against the electrode, so that the work is made to adhere to the curved surface of the electrode.

[0003]

In the plasma processing, the temperature of the work increases due to the plasma discharge. Due to this temperature rise, the work thermally expands, and particularly in the case of a work to which different materials are bonded, this thermal expansion appears in the form of a warp. The above-mentioned work pressing is intended to suppress such warpage as much as possible.However, in the conventional plasma processing apparatus, the end of the work is pressed down so as to level the work against a convex curved surface. As a result, the central part of the unpressed work is deformed by the thermal expansion.

[0004] For this reason, a gap is easily formed between the electrode and the work, and a local discharge may occur in the gap, making it difficult to perform uniform and stable plasma processing. As described above, the conventional plasma processing apparatus has a problem that it is difficult to perform uniform and stable plasma processing when a plate-shaped work is targeted.

Accordingly, an object of the present invention is to provide a plasma processing apparatus and a plasma processing method capable of performing uniform and stable plasma processing.

[0006]

According to a first aspect of the present invention, there is provided a plasma processing apparatus for performing a plasma process by mounting a plate-like work on an electrode, wherein the plasma processing apparatus includes a concave portion formed on an upper surface of the electrode. A workpiece mounting part having a curved surface, a processing chamber formed on the workpiece mounting part in an airtight manner with the outside, a vacuum exhaust part for evacuating the processing chamber, and supplying a plasma generating gas into the processing chamber. A high-frequency power supply for applying a high-frequency voltage to the electrodes, and a holding unit for pressing the work from above and bending the work to conform to the upper surface of the work mounting unit.

A plasma processing apparatus according to a second aspect is the plasma processing apparatus according to the first aspect, wherein the curved surface has a U shape.
It is a groove-like curved surface.

According to a third aspect of the present invention, there is provided the plasma processing apparatus according to the first aspect, wherein the curved surface is a spherical or mortar-shaped curved surface.

According to a fourth aspect of the present invention, there is provided a plasma processing method for performing a plasma process by mounting a plate-shaped workpiece on an electrode, wherein the workpiece has a concave curved surface formed on an upper surface of the electrode. A work is placed on the mounting portion, and a plasma generating gas is supplied into the processing chamber after evacuating the processing chamber formed airtight with the outside on the work mounting portion,
When plasma is generated in the processing chamber by applying a high-frequency voltage to the electrode to perform plasma processing on the work, the work is pressed from above and bent to conform to the upper surface of the work mounting portion. I did it.

A plasma processing method according to a fifth aspect is the plasma processing method according to the fourth aspect, wherein the curved surface has a U shape.
It is a groove-like curved surface.

According to a sixth aspect of the present invention, in the plasma processing method of the fourth aspect, the curved surface is a spherical or mortar-shaped curved surface.

According to the present invention, when a workpiece is placed on the workpiece mounting portion having a concave curved surface formed on the upper surface of the electrode and plasma processing is performed, the workpiece is pressed from above and bent to bend the workpiece mounting portion. The workpiece can be pressed against the electrode without any gaps, and uniform plasma processing without local discharge can be realized.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention, FIGS. 2A, 2B, 3 and 4 are perspective views of a work mounting portion of the plasma processing apparatus, and FIGS.
1 is a sectional view of a plasma processing apparatus according to an embodiment of the present invention.

First, the structure of the plasma processing apparatus will be described with reference to FIG. In FIG. 1, an opening 1 a is provided in a horizontally arranged base 1, and an electrode 2 is mounted in the opening 1 a from below through an insulating member 3. The electrode 2 is formed by stacking three plate-like members 2a, 2b, 2c made of a conductor such as aluminum.
The uppermost layer is provided with a work mounting portion 2c having a concave curved surface on which the substrate 4 as a plate-like work is mounted.

A lid member 5 is disposed above the base 1 so as to be vertically movable by vertical movement means (not shown). Lid member 5
Is lowered to contact the base 1, the space between the lid member 5 and the base 1 forms a processing chamber 6 sealed by a seal member 9 from the outside. A holding portion 7 is provided on the ceiling surface of the lid member 5. The holding part 7 is configured by vertically mounting a holding rod 7c inside a cylinder 7a, and the holding rod 7c is urged downward by a spring member 7b. When the lid member 5 is lowered while the substrate 4 is placed on the work placement portion 2c, the holding rod 7c contacts the upper surface of the substrate 4 and presses the substrate 4 against the work placement portion 2c. The holding portion 7 is fixed to the lid member 2 via the insulating member 8, and the substrate 4 is electrically insulated from the lid member 2 even when the holding rod 7 c is in contact with the substrate 4.

The base 1 is provided with ventilation holes 1b and 1c.
The ventilation holes 1b and 1c are connected to a vacuum exhaust unit 12 and a gas supply unit 13 via pipes 11a and 11b, respectively. The evacuation unit 12 evacuates the processing chamber 6, and the gas supply unit 13 supplies a plasma generating gas such as an argon gas or an oxygen gas into the processing chamber 6. A high-frequency power supply 14 is connected to the electrode 2, and by driving the high-frequency power supply 14, the lid member 5 connected to the ground 10 and the electrode 2 are connected.
A high-frequency voltage is applied between them.

The lowermost plate-like member 2 of the electrode 2
The water jacket 15 is mounted on the lower surface of the “a”. A cooling water pipe 16a,
The electrode 2 is cooled by circulating the cooling water through the water jacket 15 through the work mounting portion 16b.
The temperature rise of the substrate 4 placed on the substrate c is suppressed.

Next, the work mounting portion 2c of the plasma processing apparatus will be described with reference to FIGS. As shown in FIG. 2A, the upper surface of the work mounting portion 2c is formed of a concave curved surface 2d curved in a U-shaped groove only in the X direction. In a state where the substrate 4 is placed on the curved surface 2d,
A gap c is provided between the lower surface of the substrate 4 and the surface of the work mounting portion 2c.
Exists. FIG. 2B shows a state where one point at the center of the substrate 4 is pressed by the pressing rod 7c (see arrow). Due to this pressing, the substrate 4 is easily bent downward, and the lower surface of the substrate 4 is pressed without any gap following the curved surface 2d. Even when the substrate 4 thermally expands relatively to the work placing portion 2c due to the temperature rise, the displacement due to the thermal expansion is limited to the central portion of the substrate 4, that is, the constraint point pressed and fixed by the holding rod 7c. From the free end toward both ends in the X and Y directions. Therefore, the substrate 4 is displaced along the curved surface 2d without being constrained, and no gap is generated between the substrate 4 and the work placing portion 2c due to thermal expansion.

FIG. 3 shows a state in which two points on both ends of the upper surface of the substrate 4 placed on the work placing portion 2c are pressed by the pressing rod 7c. In the case of this two-point constraint, the substrate 4 has an axis A along the bottom of the concave curved surface of the U-shaped groove.
In this state, the displacement is restrained by being pressed at the upper two points. In this state, the substrate 4 is bent along the curved surface 2d, and the bending rigidity of the cross section orthogonal to the axis A of the substrate 4 due to the bent shape. Is much larger than when the substrate 4 is in a planar state. Therefore, when mounting the substrate 4 on the work mounting portion 2c having such a concave curved surface,
Even when the two-point constraint on the axis A as shown in FIG. 3 is performed, the out-of-plane deformation of the substrate 4 due to the thermal expansion accompanying the temperature rise can be suppressed to a very small value. Although the example of the two-point constraint is shown in the example of FIG. 3, the number of the constrained points may be one or three or more as long as they are on the axis A, and may be a structure that is not a point but a line.

FIG. 4 shows an example in which the upper surface shape of the work mounting portion 2c is a concave curved surface symmetrical with respect to the center point O, for example, a mortar-shaped or spherical curved surface (see a cross section B in the X and Y directions). ). By adopting such a shape, the central portion of the placed substrate 4 is pressed from above to restrain only one point, so that when thermal expansion occurs due to a temperature rise, the substrate 4 is moved in the entire circumferential direction from the restrained point. , The substrate 4 warps due to thermal expansion and the curved surface 2
A good contact state is maintained without generating a gap with d ′.

Next, a description will be given of the substrate transfer means with reference to FIG. This transfer means transfers the unprocessed substrate 4 to the processing chamber 6.
The substrate 4 is carried in, and the processed substrate 4 is carried out of the processing chamber 6. As shown in FIG. 5, the plasma processing apparatus includes two transfer heads, that is, a carry-in head 20 and a carry-out head 21. The carry-in head 20 evacuates the substrate 4 from a substrate supply unit (not shown) by a suction nozzle 22. The substrate 4 is conveyed into the processing chamber 6 with the cover member 5 opened while being picked up by suction, and the substrate 4 is placed on the upper surface of the work placing portion 2c. The unloading head 21 sucks the substrate 4 which is released from the pressing on the work mounting portion 2c and is in a flat state without bending by the suction nozzle 22, vacuums it out of the processing chamber 9, and supplies it to the next process. .

When the pressing is released, the substrate 4
At the same position, the bending disappears, and the plane returns to the flat state. In this state, the substrate 4 is in the horizontal posture, so that the substrate 4 can be picked up by the carry-out head 21 without causing a suction error. Further, since the substrate 4 remains at the same position and does not shift even after the pressing is released, there is no need to correct the position of the substrate 4 after unloading. Therefore, a position correcting mechanism is not required and the transport mechanism is simplified.

This plasma processing apparatus is configured as described above. Next, the operation will be described. First, in FIG. 5, the substrate 4 is picked up by the carry-in head 21 and mounted on the work mounting portion 2c. Next, the cover member 5 is lowered to close the processing chamber 6 and the holding rod 7 is closed.
The lower end of c is brought into contact with the upper surface of the substrate 4 and the substrate 4 is pressed against the upper surface of the work mounting portion 2c. As a result, the substrate 4 is bent and pressed in a state in which the substrate 4 follows the curved surface 2d of the work mounting portion 2c.

Then, the evacuation unit 12 is driven to drive the processing chamber 9.
The inside is evacuated, and then the gas supply unit 13 is driven to supply a plasma generation gas into the processing chamber 9. Thereafter, by driving the high-frequency power supply 12 to apply a high-frequency voltage between the electrode 2 and the cover member 5, a plasma discharge is generated in the processing chamber 9, and ions and electrons generated as a result cause the substrate 4 to generate a plasma discharge. Is plasma treated.

In this plasma processing, the temperature of the substrate 4 and the electrodes 2 rises due to the heat generated by the plasma discharge. As a result, the substrate 4 is thermally expanded and displaced relative to the work mounting portion 2c. At this time, as described above, since the surface shape of the work mounting portion 2c is a concave curved surface, a gap is generated between the lower surface of the substrate 4 and the upper surface of the work mounting portion 2c due to thermal expansion of the substrate 4. Never do. For this reason, local discharge due to the gap does not occur, and uniform plasma processing without variation can be performed.

In the process of continuously performing the plasma processing, the electrode 2 is always cooled by the water jacket 15, so that the electrode 2 is prevented from overheating. Therefore, plasma processing can be performed without causing damage to the substrate 4 due to abnormal temperature rise, and appropriate plasma processing quality can be ensured.

Thereafter, the substrate 4 on which the plasma processing has been completed is carried out by the carry-out head 21. At this time, the pressing of the substrate 4 is automatically released by raising the lid member 5, but the displacement of the substrate 4 does not occur in the pressing release operation. When transferred to the process apparatus, a correct position without any positional deviation is maintained, and the transfer with excellent positional accuracy can be performed by a simple transfer mechanism.

[0028]

According to the present invention, when a work is placed on a work placement portion having a concave curved surface formed on the upper surface of an electrode and plasma processing is performed, the work is pressed from above to bend the work. Since the workpiece is arranged on the upper surface of the work placement part, the workpiece can be pressed against the electrode without any gap, and uniform plasma processing without local discharge can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2A is a perspective view of a work mounting part of the plasma processing apparatus according to one embodiment of the present invention; FIG. 2B is a perspective view of a work mounting part of the plasma processing apparatus according to one embodiment of the present invention;

FIG. 3 is a perspective view of a work mounting portion of the plasma processing apparatus according to the embodiment of the present invention;

FIG. 4 is a perspective view of a work mounting portion of the plasma processing apparatus according to one embodiment of the present invention;

FIG. 5 is a sectional view of a plasma processing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base part 2c Work mounting part 4 Substrate 5 Lid member 6 Processing chamber 7 Holding part 12 Vacuum exhaust part 13 Gas supply part 14 High frequency power supply part 15 Water jacket 20 Carry-in head 21 Carry-out head 22 Suction nozzle

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05H 1/46 H05H 1/46 A (72) Inventor Teruaki Nishinaka 1006 Kazuma Kazuma, Kadoma, Osaka Matsushita Electric F term in Sangyo Co., Ltd. (reference) 4K030 FA03 GA02 GA12 KA08 4K057 DA11 DA16 DD01 DM03 DM35 5F004 AA01 AA06 BA04 BB15 BB17 BB18 BC06 5F045 BB16 DP04 EB02 EH04 EH14 EH19 EM02 EM09

Claims (6)

[Claims] 1. A plasma processing apparatus for performing a plasma process by mounting a plate-shaped work on an electrode, comprising: a work mounting portion having a concave curved surface formed on an upper surface of the electrode; A processing chamber airtightly formed on the unit, an evacuation unit for evacuating the processing chamber, a gas supply unit for supplying a plasma generation gas into the processing chamber, and applying a high-frequency voltage to the electrode. A plasma processing apparatus, comprising: a high-frequency power supply; and a holding unit that presses the work from above and curves the work to conform to an upper surface of the work mounting unit. 2. The plasma processing apparatus according to claim 1, wherein the curved surface is a U-shaped curved surface. 3. The plasma processing apparatus according to claim 1, wherein said curved surface is a spherical surface or a mortar-shaped curved surface. 4. A plasma processing method for performing a plasma process by mounting a plate-shaped work on an electrode, wherein the work is mounted on a work mounting portion having a concave curved surface formed on an upper surface of the electrode. After evacuating the processing chamber airtightly formed on the workpiece mounting portion and supplying a plasma generating gas into the processing chamber and applying a high-frequency voltage to the electrodes, plasma is generated in the processing chamber. When performing the plasma processing on the work, the work is pressed from above to bend and bend so as to be flush with the upper surface of the work mounting portion. 5. The plasma processing method according to claim 4, wherein the curved surface is a U-shaped curved surface. 6. The plasma processing method according to claim 4, wherein said curved surface is a spherical surface or a mortar-shaped curved surface.