JPH11106962A - Plasma processing equipment - Google Patents

Abstract

(57) [PROBLEMS] A plasma processing apparatus capable of improving the reproducibility and stability of a process for a large-diameter workpiece by forming a plasma having a uniform and stable electric potential over a large area. The purpose is to provide. SOLUTION: The plasma processing apparatus of the present invention supplies a plasma chamber 2 in which a plasma is generated by an excitation source using a gas in a vacuum vessel, and a driving device 9 to supply the gas into the vacuum vessel in a pulsed manner. Pulse gas valve 8
A conductor having a fixed upper portion, which is a part of the plasma chamber 2, a processing chamber 1 in which the sample 7 is arranged in the vacuum chamber, and a processing chamber 1 and the plasma chamber 2. And a partition plate 3 having a hole 4 communicating from the plasma chamber 2 to the processing chamber 1, and a vacuum exhaust unit (not shown) for exhausting the processing chamber 1.

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 more particularly, to a plasma processing apparatus for forming a thin film on a surface of an object using plasma or etching the surface of the object. About.

[0002]

2. Description of the Related Art In recent years, the diameter of an object to be processed by a plasma processing apparatus has been increased, and a technique for uniformly processing the object having a large diameter has been demanded. In order to meet this demand, it is necessary to increase the area of the plasma.

FIGS. 7 and 8 show Japanese Patent Application Laid-Open No. 7-263353.
FIG. 1 is a schematic cross-sectional configuration diagram illustrating a conventional plasma processing apparatus described in Japanese Unexamined Patent Application Publication No. H10-115,004. In FIG. 7, a sample 7 is placed in a processing chamber 1.
Is mounted on the stage 6. Plasma chamber 2
Is installed above the processing chamber 1, and a microwave is introduced from the waveguide 11 through the microwave introduction window 12.

[0004] An etching gas is supplied to the plasma chamber 2 through a gas introduction pipe 10 and a pulse gas valve 8.
The pulse gas valve 8 is controlled by a driving device 9 and supplies an etching gas to the plasma chamber 2 in a pulsed manner.

The partition plate 3 separates the plasma chamber 2 from the processing chamber 1 and has a hole 4. The exhaust port 5 is connected to an exhaust system (not shown), and evacuates the processing chamber 1.
A magnetic field coil 13 for applying a magnetic field to the plasma chamber 2 is provided near the plasma chamber 2.

In the plasma processing apparatus constructed as described above, the etching gas introduced from the pulse gas valve 8 into the plasma chamber 2 is exhausted from the hole 4 of the partition plate 3 through the processing chamber 1 and from the exhaust port 5. You.

At this time, 2.45 GHz is set in the plasma chamber 2.
Is introduced, and a magnetic field of 875 gauss is formed in the plasma chamber 2 by the magnetic field coil 13, an electron cyclotron resonance plasma is generated. The generated plasma is transported from the holes 4 of each flat plate 3 to the processing chamber 1 and etches the sample.

The pulse gas valve 8 is turned on and off by a signal from a drive unit 9. Pulse gas valve 8 is O
During the opening in the N state, an etching gas is introduced and O
While closed in the FF state, the supply of the etching gas is stopped.

If the vacuum capacity of the exhaust system is constant, the plasma chamber 2 and the processing chamber 1 are operated with the operation of the pulse gas valve 8.
Changes over time. Pulse gas valve 8 is ON
When the etching gas is introduced in this state, the pressure in the plasma chamber 2 temporarily increases, and a state in which the pressure difference from the processing chamber 1 becomes large is realized.

Therefore, even if the hole 4 of the partition plate 3 is made large and a large number of holes 4 are provided in a wide range in order to guide a large-area plasma to the processing chamber 1 corresponding to a large-diameter sample, the plasma chamber The pressure difference between the pressure chamber 2 and the processing chamber 1 can be kept large.

FIG. 8 has the same configuration as that of the etching apparatus shown in FIG. 7, except that the waveguide 11, the microwave introduction window 12 and the magnetic field coil 13 are omitted, and the RF power applying means 270 is provided. Have been. Also, the side wall 2 of the plasma chamber 2
Reference numeral 71 is formed of a dielectric material such as quartz.

The RF power applying means 270 includes the RF coil 2
A plasma RF power supply 277 for applying RF power to 72 is provided, and the RF coil 272 is arranged around the side wall 271.

When an etching gas is introduced from the pulse gas valve 8 into the plasma chamber 2 and RF power is applied to the RF coil 272, plasma is generated in the plasma chamber 2. In this case, the plasma chamber 2 is formed by induction coupling.
The discharge starts from the surface of the side wall 271 and is combined with the generated plasma.

[0014]

The conventional plasma processing apparatus is constructed as described above, is provided with a partition plate, has a two-chamber structure including a plasma chamber and a processing chamber, and has a pulse gas valve in the plasma chamber. By supplying the etching gas in a pulsed manner, a large-diameter workpiece can be uniformly processed. However, although a higher processing speed and a more uniform processing shape are desired for a large-diameter workpiece, deposits are formed on the walls of the plasma chamber during the processing of the workpiece, and the potential of the generated plasma is increased. Causes unevenness,
There is a problem that the processing speed, processing shape, and the like of the processing object are unstable.

Accordingly, the present invention has been made to solve the above problems, and provides a plasma processing apparatus capable of forming a uniform plasma over a large area and stably processing a large-diameter workpiece. The purpose is to:

[0016]

The invention according to claim 1 is
A plasma chamber in which plasma is generated by an excitation source using a gas in a vacuum vessel, gas supply means for supplying the gas in a pulsed manner into the vacuum vessel, and an object to be processed are arranged in the vacuum vessel. In the vacuum chamber, the processing chamber and the plasma chamber are separately formed, and a partition plate having a hole communicating from the plasma chamber to the processing chamber, and the plasma chamber is formed. A conductor whose contact is fixed at least in part at a constant potential,
A plasma processing apparatus comprising: a vacuum exhaust unit that exhausts the processing chamber.

A second aspect of the present invention is the plasma processing apparatus according to the first aspect, wherein the conductor is provided on at least a part of an upper portion or a side wall of the plasma chamber.

A third aspect of the present invention is the plasma processing apparatus according to the first aspect, wherein the conductor is a partition plate or a part of the partition plate.

A fourth aspect of the present invention is the plasma processing apparatus according to the first aspect, wherein the conductor is provided on the partition plate.

The invention according to claim 5 is the invention according to claims 1 to 4
The plasma processing apparatus according to any of the above, wherein the conductor is coated with an insulating film.

The invention according to claim 6 is the plasma processing apparatus according to claim 5, wherein the thickness of the insulating film is 100 μm or less.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plasma processing apparatus according to the present invention will be described below with reference to the drawings, taking an etching apparatus as an example.

FIG. 1 is a sectional view showing a schematic configuration of a plasma dry etching apparatus according to an embodiment of the present invention, wherein an ICP (Inductive) is used for plasma generation.
yCoupled Plasma) is shown. A processing chamber 1 is provided in a vacuum vessel. In the processing chamber 1, a stage 6 on which a sample (object to be processed) 7 is mounted is provided. The stage 6 is supplied with high frequency power from a high frequency power supply (not shown).
Further, a plasma chamber 2 is provided in the vacuum chamber with a partition plate 3 interposed with respect to the processing chamber 1. A plurality of holes 4 are provided in the partition plate 3.

The plasma chamber 2 has an inner side wall 271.
Is formed of a dielectric material such as quartz glass or ceramic. The upper portion of the plasma chamber 2 is formed of a conductor 50 made of a metal such as aluminum or stainless steel, for example, and its potential is fixed. The material that can be used for the conductor 50 depends on the type of the workpiece 7 to be etched, but in addition to the above-described materials, a conductive material such as carbon or silicon can be used. A pulse gas valve 8 that is turned on and off by a driving unit 9 is provided in the upper part on the side of the plasma chamber 2, and an etching gas is supplied in a pulse form from a gas introduction pipe 10 through the pulse gas valve 8.

The RF power applying means 270 includes the RF coil 27
2 is provided with a plasma RF power source 277 for applying RF power to the plasma chamber 2, and the RF coil 272 is arranged around the side wall 271 of the plasma chamber 2.

The etching gas supplied from the gas introduction pipe 10 via the pulse gas valve 8 is supplied to the plasma chamber 2. The etching gas supplied to the plasma chamber 2 passes through the hole 4 provided in the partition plate 3 and is led to the processing chamber 1. After that, the air is exhausted from the exhaust port 5 to the outside. To discharge the etching gas to the outside, the processing chamber 1 is evacuated by a vacuum pump (not shown). The processing chamber 1 is maintained at a higher vacuum than the plasma chamber 2.

When an etching gas is introduced from the pulse gas valve 8 into the plasma chamber 2 and RF power is applied to the RF coil 272, plasma is generated in the plasma chamber 2.

In the present embodiment, since the upper portion of the plasma chamber 2 which is in contact with the plasma is formed of a conductor and the potential is fixed, the potential of the generated plasma can be always kept constant. Thus, reproducibility and stability of the etching process can be ensured.

The conductor 50 having a fixed potential may be provided in at least a part of the inside of the plasma chamber 2. FIG. 2 shows an example provided below the side wall of the plasma chamber 2.

FIG. 3 shows a structure in which the partition plate 3 is formed of a conductor. A part of the partition plate 3, for example, the entire surface except for the hole 4 on the plasma chamber 2 side or the peripheral surface is formed of a conductor. Is also good.

FIGS. 1 to 3 show a configuration in which a part of the plasma chamber 2 or the partition plate 3 is used as the conductor 50.
0 may be provided.

Further, at least a part provided on the surface of the conductor in the plasma chamber 2, varies depending on the kind of object to be processed, for example, other SiO _2, Al ₂ O _3, be coated with an insulating film such as a ceramic Accordingly, generation of heavy metals and the like from the conductor 50 can be suppressed, and the object can be processed cleanly. FIG. 4 shows a plasma processing apparatus in which a conductor 50 on the upper part of the plasma chamber 2 is covered with an insulating film 51. FIGS. 5 and 6 show a plasma processing apparatus formed on the lower part of the side wall of the plasma chamber 2 and the plasma chamber of the partition plate 3, respectively. 2 shows a plasma processing apparatus in which the surface of a conductor 50 formed on the second surface is covered with an insulating film 51.

In the case of covering with the insulating film 51, if the thickness of the insulating film 51 is too thick, the effect of keeping the potential of the plasma constant cannot be obtained, so that the thickness is preferably 100 μm or less.

In the above-described embodiment, an IPC type plasma generator has been described as a type of generating plasma. However, the present invention is not necessarily limited to this type. For example, other inductive coupling type, ECR type, magnetron type The same operation and effect can be obtained by using a parallel plate type plasma generator or the like.

Therefore, it should be understood that the embodiments disclosed herein are illustrative in all aspects and not restrictive. The scope of the invention is not described above,
It is indicated by the appended claims, and is intended to include any modifications within the scope and meaning equivalent to the appended claims.

[0036]

The present invention has the following effects. According to the first to fourth aspects of the present invention, since the plasma chamber is formed and at least a part in contact with the plasma is a conductor fixed at a constant potential, the potential of the generated plasma can be always kept constant. Thus, reproducibility and stability of the etching process can be ensured.

According to the fifth aspect of the present invention, since the conductor is covered with the insulating film, it is possible to suppress the generation of foreign matter which causes contamination from the conductor and clean the object to be processed. it can.

According to the sixth aspect of the present invention, since the thickness of the insulating film is 100 μm or less, the function of the conductor is preferably exhibited, and the plasma potential can be kept constant.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a plasma dry etching apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing a plasma dry etching apparatus according to another embodiment of the present invention.

FIG. 3 is a sectional view schematically showing a plasma dry etching apparatus according to another embodiment of the present invention.

FIG. 4 is a sectional view schematically showing a plasma dry etching apparatus according to another embodiment of the present invention.

FIG. 5 is a sectional view schematically showing a plasma dry etching apparatus according to another embodiment of the present invention.

FIG. 6 is a sectional view schematically showing a plasma dry etching apparatus according to another embodiment of the present invention.

FIG. 7 is a cross-sectional configuration diagram schematically showing a conventional plasma dry etching apparatus.

FIG. 8 is a cross-sectional configuration diagram schematically showing a conventional plasma dry etching apparatus.

[Explanation of symbols]

1 processing chamber, 2 plasma chamber, 3 partition plate, 4 holes, 5
Exhaust port, 6 stage, 7 sample (workpiece), 8
Pulse gas valve, 9 driving device, 10 gas introduction pipe,
Reference Signs List 50 conductor, 51 insulating film, 270 RF power applying means, 271 side wall, 272 RF coil, 277 plasma RF power supply

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Kazuyasu Nishikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Shingo Tomohisa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Tatsuo Omori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (6)

[Claims] 1. A plasma chamber in which plasma is generated by an excitation source using a gas in a vacuum vessel, gas supply means for supplying the gas into the vacuum vessel in a pulsed manner,
A processing chamber in which an object to be processed is disposed in the vacuum chamber, and a partition plate having a hole that forms the processing chamber and the plasma chamber separately in the vacuum chamber and communicates with the processing chamber from the plasma chamber. A plasma processing apparatus comprising: a conductor that forms the plasma chamber and has at least a part in contact with the plasma and has a fixed potential; and a vacuum exhaust unit that exhausts the processing chamber. 2. The plasma processing apparatus according to claim 1, wherein the conductor is provided on at least a part of an upper portion or a side wall of the plasma chamber. 3. The plasma processing apparatus according to claim 1, wherein the conductor is a partition plate or a part of the partition plate. 4. The plasma processing apparatus according to claim 1, wherein the conductor is provided on the partition plate. 5. The plasma processing apparatus according to claim 1, wherein the conductor is covered with an insulating film. 6. The plasma processing apparatus according to claim 5, wherein the thickness of the insulating film is 100 μm or less.