JPS60237283A - Plasma treatment device - Google Patents

Abstract

PURPOSE:To maintain the sealing function of a stop valve in good for a long period of time by a method wherein solid particles, acoompanied by purge gas discharged to the outside of a cooling trap, are collected and removed at the fore stream side of the stop valve, through which the purge gas passes. CONSTITUTION:The plasma treatment device is provided with a solid particles collector 50 between the cooling trap 30 of a reduced pressure air discharging system provided in a treatment chamber 10, processing a specimen under a reduced pressure utilizing plasma, and the stop valve 40 provided in a purge gas discharging line 39 connected to the trap. Accordingly, the solid particles are collected and removed at the fore stream side of the stop valve, therefore, the seal function of the stop valve will never be spoiled by the solid particles and may be maintained in stable state for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus equipped with a reduced pressure exhaust system having a cooling trap.

[Background of the invention]

As a plasma processing apparatus equipped with a reduced pressure exhaust system having a cooling trap, for example, as shown in JP-A-56-77381, a cooling trap is installed in a processing chamber that etches a sample under reduced pressure using plasma. It is known that the exhaust system is equipped with an exhaust system having the following characteristics.

In this device, the cooling trap is regenerated by heating the cooling trap with a heater and blowing pressurized air into the cooling trap as purge gas and discharging it outside the cooling trap. When solid particles are entrained, there is a problem that the sealing function of the shutoff valve through which the purge gas passes is obstructed by the solid particles.

[Purpose of the invention]

An object of the present invention is to collect and remove solid particles accompanying the purge gas discharged outside the cooling trap on the upstream side of the shut-off valve through which the purge gas passes, thereby prolonging the sealing function of the shut-off valve. An object of the present invention is to provide a plasma processing apparatus that can be maintained satisfactorily over a long period of time.

[Summary of the invention]

The present invention provides solid particle capture between a trap of a vacuum exhaust system installed in a processing chamber that processes samples under reduced pressure using plasma and a shutoff valve installed in a purge gas exhaust line connected to the trap. This device is characterized by the installation of a collector, and attempts to collect and remove solid particles accompanying the purge gas discharged outside the cooling trap on the upstream side of the shutoff valve through which the purge gas passes. .

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, a processing chamber 10 in which a sample is processed under reduced pressure using plasma is provided with a reduced pressure exhaust system. The reduced pressure exhaust system is supplied with a pressure regulating valve 21 and a reduced pressure exhaust device, for example.
Consists of an oil rotary vacuum pump and a decompression exhaust line,
A cold trap, for example, a liquid nitrogen trap (hereinafter referred to as LN)
, trap) 30. The processing gas outlet of the processing chamber 10 and the suction port of the oil rotary vacuum pump n are connected by a reduced pressure exhaust line, and the reduced pressure exhaust line n is provided with a pressure regulating valve 4. An LN2 trap (capital) is installed in the decompression exhaust line B on the downstream side of the pressure regulating valve B.
A closing valve array 25 is provided in the decompression exhaust line B between the pressure regulating valve 4 and LN2) lap (equipment) and LN, trap (equipment) and the oil rotary vacuum pump n.

The LN and trap are each composed of an inner tank 31 and an outer tank that airtightly forms a space n with the inner tank 31.

The inner tank 31 is provided with a heater U connected to a power source (not shown), and connected to an LN2 supply line connected to an LN supply source (not shown) and provided with a shutoff valve. In the outer tank, a purge gas supply line 9 connected to a purge gas supply source (not shown) and provided with a shutoff valve 37 is connected in communication with the space, and a purge gas discharge line 9 is connected in communication with the space. ing. A shutoff valve is installed in the purge gas exhaust line, and a solid particle collector, for example, a solid particle collector that does not cause clogging and causes almost no change in flow path conductance over time, is installed on the upstream side of the shutoff valve. A collector, for example a cyclone father, is provided. In addition,
Purge gas discharge line (for example, exhaust gas treatment equipment I
(hereinafter abbreviated as scrubber) 60.

The power is turned off, the shutoff valve 40 is closed, the shutoff valve is opened, and LN is supplied to the inner tank 31.
is cooled to LN, temperature. On the other hand, by opening the pressure control valve 25 and operating the oil rotary vacuum pump 4, the inside of the processing chamber 10 is evacuated to a predetermined pressure. Thereafter, processing gas is supplied to the processing chamber 10 at a predetermined flow rate from the processing gas supply device W (not shown), and the pressure inside the processing chamber 10 is regulated and maintained at a predetermined processing pressure by the pressure regulating valve B. Ru. In this state, the processing gas is turned into plasma by glow discharge, and using this plasma, the sample (not shown) in the processing chamber 10 is subjected to predetermined processing such as etching processing and film forming processing. During this processing period, the processing gas, which is discharged from the processing chamber 10 to the vacuum exhaust line along with the solid particles generated in the processing chamber 10, is supplied to the LN 21-wrap space. Among the processing gases, condensed gas is condensed and adsorbed in the inner tank 31 , and solid particles entrained in the processing gas are also adsorbed in the inner tank 31 . In addition, the remaining non-condensable gas is LN, trap (capital)
After exiting, it is evacuated by oil rotary vacuum pump B. When the adsorption capacity of the LN wrap (capital) decreases due to the adsorption of condensed gas and solid particles, the shutoff valves 24, 25, and 35 are closed, and the operation of the oil rotary vacuum pump n is stopped. After that, open the shutoff valve and supply purge gas, for example, nitrogen gas (hereinafter abbreviated as GN) from the par-8 gas supply source to the space of the LN2 trap chrysanthemum,
As a result, when the pressure in the space 32 reaches atmospheric pressure, the shutoff valve is opened. and solid particles are liberated from the inner tank 31 into the space.In Fig. 2, the liberated condensable gas and solid particles are
N is introduced along with the purge gas discharge line 39 in a tangential direction to the straight body part 51 of the cyclone group, and the straight body part 5
A turning motion is given within 1. At this time, the solid particles fall along the inner wall of the straight body part 51, and the ON gas containing condensed gas flows upward from the center of the straight body part 51 and is introduced into the purge gas discharge line through the shutoff valve. It is supplied to the scrubber ω and processed there. On the other hand, the fallen solid particles are stocked in the solid object receiver 52.

Note that, when a predetermined amount of solid particles 70 are stocked in the solid object receiver 52, the solid object receiver 52 is removed and cleaned.

In the plasma processing apparatus of this embodiment, the solid particles accompanying the OH2 discharged outside the LN2 trap can be collected and removed by the cyclone on the upstream side of the shutoff valve provided in the purge gas discharge line. The sealing function of the valve is not inhibited by solid particles, and the sealing function of the shutoff valve can be maintained satisfactorily over a long period of time.

〔Effect of the invention〕

As explained above, the present invention provides a cooling trap of a vacuum exhaust system provided in a processing chamber that processes a sample under reduced pressure using plasma, and a shutoff trap provided in a purge gas exhaust line connected to the trap. By installing a solid particle trap between the cooling trap and the valve, solid particles accompanying the purge gas discharged outside the cooling trap can be collected and removed on the upstream side of the shutoff valve installed in the purge gas discharge line. Therefore, the sealing function of the shutoff valve is not inhibited by solid particles.
This has the effect that the sealing function of the shutoff valve can be maintained well over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an exhaust system showing an embodiment of a plasma processing apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view of the cyclone shown in FIG. 1. 10...Processing chamber, heating...exhaust system, chrysanthemum...
...LN, l-lap, (...Purge gas discharge line, Shutoff valve, Seki...
Cyclone agent Patent attorney Akira Takahashi Unemployment 1 Figure 3I=2■

Claims (1)

[Scope of Claims] 1. In an apparatus in which a processing chamber for processing a sample under reduced pressure using plasma is provided with a reduced pressure exhaust system having a cooling trap, the cooling trap. A plasma processing apparatus characterized in that a solid particle collector is provided between a shutoff valve provided in a purge gas discharge line connected to the trap.