JPH10261619A - Plasma processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the bonding of foreign matters onto a vacuum container especially onto the contact part with plasma, thereby decreasing the production of the foreign matters by providing a sustaining means for the plasma producer in the vacuum container at the temperature exceeding the heating temperature of a specimen. SOLUTION: A specimen 7 as a object to be treated with its treatment surface turned upward is mounted on a specimen base 6, so that a plasma producer is arranged above the specimen 7. Accordingly, foreign matters produced in the plasma producer fall down by gravity to be bonded onto the specimen 7. In such a constitution, the bonded items re-dissociated by plasma to be bonded onto the inner wall of a vacuum container 5 are produced in a plasma producer bordered on a grid 10, so that a heater 11 may be arranged on the plasma generator side of the vacuum container 5 to be heated sustained at the temperature exceeding the treatment temperature of the specimen 7 for avoiding the redissociation. Through these procedures, the bonded item amount onto the plasma producer of the vacuum container 5 can be reduced, thereby enabling the foreign matter production to be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus suitable for ashing a resist film provided on a sample such as a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, as a plasma processing for removing a resist mask, for example, as described in Japanese Patent Application Laid-Open No. 1-175231, heat is applied to a semiconductor wafer via a heating stage and introduced into a plasma generating section. A technique is known in which the processed gas is converted into plasma by microwaves and downflow ashing is performed using a shower plate.

[0003] Japanese Patent Application Laid-Open No. 1-234847 discloses an apparatus for processing a sample using a down flow of plasma, in which a chamber is provided with an external heater.

[0004]

In a submicron semiconductor manufacturing process using plasma, it is necessary to reduce the amount of foreign matter adhering to the sample and perform the plasma processing. In the above-described conventional plasma processing apparatus, particularly, a plasma processing apparatus for performing ashing, consideration has been given to a vacuum container constituent material, a vacuum container constituent material surface treatment, a vacuum container structure, and the like in order to reduce foreign substances. These were all focused on foreign substances emitted from the constituent materials of the vacuum vessel itself or carbon to be subjected to ashing. However, it is not considered that the waste gas generated from the metal component of the sample to be processed is redissolved by the plasma, adheres to the inside of the vacuum vessel, and the extraneous matter is generated due to the detachment of the adhered substance. Was. Since the plasma processing apparatus that performs the incineration process includes only the processing gas for carbon, such deposits having a metal component cannot be removed by plasma cleaning or the like, and the vacuum container is periodically released. Cleaning had to be performed to remove the deposits.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress foreign matter from adhering to a vacuum vessel, particularly to a portion in contact with plasma, to suppress the amount of foreign matter, to keep the frequency of cleaning with the release of a vacuum device low, and to reduce the operating rate. To provide a high-performance plasma processing apparatus.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a vacuum vessel in which a processing gas is supplied and a reduced pressure is maintained at a predetermined pressure, a plasma generating means for generating plasma in the vacuum vessel, This is achieved by providing a means for maintaining the plasma generating section at a temperature equal to or higher than the heating temperature of the sample.

By implementing the above means, the amount of deposits on the plasma generating portion of the vacuum vessel can be reduced, the amount of deposits coming into contact with high-energy plasma can be reduced, and the amount of foreign substances generated can be reduced. Thereby, foreign substances adhering to the sample can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the plasma processing apparatus of the present invention will be described below with reference to FIG. The plasma processing apparatus of FIG. 1 utilizes microwaves as a means for generating plasma. 1 is a magnetron that generates a microwave, 2 is a rectangular waveguide that propagates the microwave from the magnetron 1, and 3 is a cylinder that is connected to the rectangular waveguide 2 and propagates the microwave from the rectangular waveguide 2. In the cavity, 4 is a microwave transmitting window (for example, a quartz flat plate), 5 is a vacuum container connected to the cylindrical hollow portion 3 through the microwave transmitting window 4, and is formed by the vacuum container 5 and the microwave transmitting window 4. The inside of the vacuum vessel 5 is kept airtight. Reference numeral 6 denotes a sample stage provided at the bottom of the vacuum vessel 5 for placing a wafer 7 as a sample.
Reference numeral 8 denotes a valve provided on a gas supply line for introducing a processing gas into the vacuum vessel 5. Reference numeral 9 denotes a plasma generated in the vacuum vessel 5, reference numeral 10 denotes a ground potential grid having a large number of holes through which charged particles generated from the plasma 9 pass and neutralizing the charged particles, and reference numeral 11 denotes a vacuum. A heater for heating the plasma generating portion of the container 5;
Is a cooling water passage for cooling the cylindrical cavity 3. An exhaust device (not shown) is connected to the bottom of the vacuum vessel.

In the apparatus configured as described above, the processing gas is supplied into the vacuum vessel 5 through the valve 8, and the inside of the vacuum vessel 5 is maintained at a predetermined pressure by an exhaust device (not shown). . In this state, the microwave generated by the magnetron 1 was introduced into the vacuum vessel 5 through the rectangular waveguide 2, the cylindrical cavity 3, and the microwave transmission window 4, and was supplied into the vacuum vessel 5. The processing gas is turned into plasma. The charged particles in the plasma 9 follow the gas flow in the vacuum vessel 5 and flow toward the sample 7 through many holes of the grid 10. At this time, the charged particles are grounded when passing through the grid 10 and become neutral particles, that is, neutral radicals. Neutral radicals that have passed through the grid 10 come into contact with the sample, react with a predetermined material on the surface of the sample 7, for example, react with a resist mask provided on the surface of the sample 7, and remove the resist mask.

At this time, the reaction product from the sample 7 may float in the vacuum vessel 5 or the plasma 9 may hit the grid 10 to generate foreign matter. Sample 7
Among the reaction products from the above, there is also a waste gas of a reaction product having a metal component of the sample. When the waste gas floats in the vacuum vessel 5, it is redissolved by the plasma and adheres to the inner wall of the vacuum vessel 5. Thus, it was also found that the adhered substance was peeled off and dropped on the sample 7 to cause foreign matter. Generally, the surface of the sample 7 to be processed, which is to be treated by the plasma, is placed on the sample stage 6 with the plasma facing upward, so that the plasma generating section is arranged above the sample 7. Therefore, the foreign matter generated in the plasma generating unit falls down due to gravity and adheres to the sample. In this case, the deposits re-dissociated by the plasma and adhering to the inner wall of the vacuum vessel 5 are generated on the side of the plasma generating section with the grid 10 as a boundary. 11 is provided, and the plasma generator side of the vacuum vessel 5 is heated and held by the heater 11 at a temperature higher than the processing temperature of the sample 7.
The re-dissociation material is prevented from adhering.

In this manner, by keeping the plasma generating section of the plasma processing apparatus at a temperature higher than the heating temperature of the workpiece, the amount of deposits on the plasma generating section of the vacuum vessel 5 can be reduced, and the plasma comes into contact with high-energy plasma. The amount of deposits is reduced, and the amount of foreign substances generated can be reduced.

[0012]

According to the present invention, the amount of deposits on the plasma generating portion of the vacuum vessel can be reduced, the amount of deposits coming into contact with high-energy plasma can be reduced, and the amount of foreign matter generated can be reduced. is there.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a vacuum processing apparatus according to one embodiment of the present invention.

[Explanation of symbols]

1: magnetron, 2: rectangular waveguide, 3: cylindrical hollow part,
4 ... Microwave transmission window, 5 ... Vacuum container, 6 ... Sample stand, 7
... sample, 8 ... bulb, 9 ... plasma, 10 ... grid,
11: heater, 12: cooling water channel.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shingo Kimura 794, Higashi-Toyoi, Kazamatsu City, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd.

Claims (3)

[Claims] 1. A vacuum vessel in which a processing gas is supplied and maintained at a reduced pressure at a predetermined pressure, plasma generating means for generating plasma in the vacuum vessel, and a plasma generating section of the vacuum vessel for applying a sample. A plasma processing apparatus comprising: means for maintaining a temperature at or above a temperature. 2. The plasma processing apparatus according to claim 1, wherein the plasma generating section is separated from the sample side by a porous ground potential grid in the vacuum vessel. 3. The plasma processing apparatus according to claim 2, wherein the processing of the sample by the plasma is ashing of a resist film.