JPS60159178A - Dry etching device - Google Patents

Abstract

PURPOSE:To avert the danger by a cold spot and to improve the stability and maintenance performance of a device by installing a dry type strainer before an evacuating system and removing the solid components in the resulted product of reaction. CONSTITUTION:A strainer 16 of a dry type is installed before an evacuating device of a dry etching device and only the valve 6 for purging an inert gas is used for the valve to introduce a gas into the evacuating system. The gas evacuated from an etching reaction chamber 2 flows through a valve 3 and a mechanical booster pump 6 to the strainer 16 where mainly the solid components in the resulted product of reaction are removed in the stage before a rotary pump 14. The inert gas is blown through a gas introducing port 13 into the casing of the pump 14 to prevent the appearance of the solid resulted product of reaction in the pump 14. The maintenance period of the device is thus extended and the stable operation of the device is assured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry etching apparatus, and more particularly to an exhaust treatment method.

[Prior art]

Conventionally, when using a reactive gas containing fluorine as a product in the exhaust treatment method of dry etching equipment,
Even without special precautions, troubles caused by reaction products, such as clogging of exhaust pipes or early deterioration of pumps, did not occur.

However, in recent years, it has become common to etch M and the like using a reactive gas containing chlorine as a main component as an etching gas. In this case, a so-called cold trap Ccolcl is used as a reaction product collection system cooled with liquid nitrogen, mainly from the viewpoint of pump protection.
trap) in the front stage of the rotary pump in the exhaust system,
It is common to collect the reaction products and any excess etching gas that has been consumed in the etching reaction chamber.

However, when collecting reaction products and residual etching gas by such a method, the seven stems become complicated and a portion where vacuum leakage occurs is removed. Also, this trap part itself is filled with liquefied etching gas, which is extremely dangerous. Furthermore, slight fluctuations in the temperature of the cold trap may cause the collected liquefied gas components to flow back into the reaction chamber, disrupting the etching conditions and resulting in the product being etched to be defective. become. This will be explained below using the drawings.

FIG. 1 is a purchasing diagram of a conventional dry etching apparatus. The reactive etching gas introduced from the etching gas inlet 1 is consumed as etching gas under glow discharge in the etching chamber 2, and at the same time, the remaining etching gas containing reaction products generated by the reaction passes through the mechanical etching gas. After passing through the booster pump 4 and valve 5, the liquid nitrogen temperature near the cold 1-lap 9 (~
The liquid nitrogen is condensed and collected at 80″K).
From 1, d: is entered. Due to uncollected gas components and lack of suitable sensors, the overflow gas passes through valve IO to rotary pump 14 due to undetectable cold trap 9 even when it is full.
Some of it is collected in the oil and discharged to the outside. That is,
At the practical stage, in most cases, the cold trap 9 loses its function to protect the rotary pump.

In addition, when the cold trap 9 (hereinafter abbreviated as trap 9) is filled and the liquefied gas component 7 is expelled, the pulp 8 is opened after closing the valve 5 and valve 10, the temperature of the trap 9 is raised, and the gas is vaporized through the valve 8. Excrete components. Next, the valve 6 is opened and an inert gas is introduced from the purge gas introduction lower to purge the inside of the trap 9. Next is trap 9
Disassemble and clean the element outside the device. As described above, the procedure is complicated, but in addition, the valve 8 is easily destroyed by etching reaction products, etc. In this case, raising the temperature of the trap 9 will help vaporize the trapped liquefied gas. This is extremely dangerous as a sudden and large increase in pressure will cause dangerous gas to blow out from the seals of the trap 9 or the seals of the valves 5, 6, 8, 10, etc. Moreover, if the above-mentioned blowout does not occur, assuming the worst case scenario, there may even be a danger that the trap 9 will explode.

As described above, the conventional apparatus has serious drawbacks both in terms of stable etching of products and in terms of safety.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry etching apparatus capable of eliminating the above-mentioned drawbacks and performing stable and safe dry etching.

[Structure of the invention]

The present invention is a dry etching apparatus that uses chlorine or a reactive gas containing chlorine and fluorine as main components as an etching gas, and is characterized in that a dry strainer is installed upstream of the exhaust system. It is a device.

[Explanation of Examples]

An embodiment of the present invention will be described below with reference to the drawings.

In the exhaust section of the dry etching equipment, it is undesirable to have a part of the system with a lower temperature than other parts, a so-called cold spot. From the viewpoint of the stability of the device, it is important to exhaust the gas to the outside of the vacuum.

Therefore, as shown in FIG. 2, the present invention has a dry strainer 16 installed in the exhaust system of the dry etching apparatus. As a result, the only valve for introducing gas into the exhaust system from outside the vacuum is the inert gas blow valve 6. Exhaust from the etching reaction chamber 2- passes through a valve 3, a mechanical booster pump 4, and a dry strainer 16. In the dry strainer 16, solid components in the reaction product are mainly removed before the rotary pump 14.

Therefore, the possibility of solid matter forming after the valve 10 is in the casing of the pump 14, after the part that becomes atmospheric. To prevent this, valve 1 is connected to gas inlet 13.
2, an inert gas is blown into the casing of the rotary pump 14 to prevent the appearance of solid reaction products in the pump 14. Therefore, the period for overhaul and maintenance of both the oil filter system 15 and the rotary pump 14 becomes longer, and the oil filter system 15 and rotary pump 14 operate stably. Furthermore, the dangers caused by the aforementioned cold spots as in the conventional method can also be avoided. If maintenance of the strainer 16 is required after long-term use, first close the valve 5 and exhaust the inside of the strainer 16 using the rotary pump 14, then open the valve 6 and introduce inert gas from the gas introduction lower to drain the strainer. Purging the inside of the strainer 16. Then, close the valve 10 and disassemble the strainer 16.

FIG. 3 is a sectional view of the strainer 16 of FIG. 2. In FIG. 3, a gas inlet 17 is provided on the side of the casing 17.
a, an exhaust port 17b is provided at the top thereof,
A cylindrical stainless steel mesh 18 is installed inside the casing F, and a cylinder 19 made of a perforated plate is installed inside the mesh. The scum flows from the gas inlet 17cL to the casing 17.
The air enters the air, passes through the stainless steel mesh 18, passes through the cylinder 19 having pores, and is discharged from the exhaust port 176 to the rotary pump side. Casing 17, mesh 18 and cylinder 1
9 are all made of highly corrosion-resistant stainless steel. If maintenance is required, remove the screws 20 at the bottom and remove the bottom plate 21 as shown in Figure 3.
A mesh 18 and a cylinder 19 are easily removed from a casing 17.

22 is a sealing material.

In the above embodiment, a mechanical booster pump and a rotary pump have been described, but it goes without saying that a turbo molecular pump may be provided in place of the mechanical booster pump (of course, this can be implemented in various ways).

〔Effect of the invention〕

As explained in detail above, according to the present invention, there is no need to generate cold spots in the exhaust system of the device, and the exhausted gas is discharged as a vaporized gas, so there is no danger of cold spots. This has the effect of greatly improving the stability, maintainability, etc. of the device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a dry etching apparatus having a conventional cold trap, Fig. 2 is a block diagram of a dry etching apparatus showing an embodiment of the present invention, and Fig. 3 (d) is a structural sectional view of a dry strainer. 1. Etching gas inlet, 2. Etching chamber,
3.5, 6.12... Valve, 4... Mechanical booster pump, 7, 13... Inert gas inlet, 9.
・Cold trap, 11...Liquid nitrogen inlet, 14
...Rotary pump, 15...Oil filter system, 16...Dry strainer-117...Strainer casing, 18...Mesh, 19...
Cylindrical patent applicant NEC Corporation representative Patent attorney Naka Kanno, p<, P5a) Figure 1

Claims (1)

[Claims] (1) In dry etching equipment that uses chlorine or a reactive gas containing chlorine and fluorine as the main components as etching gas, a dry strainer is installed before the exhaust system.
A dry etching device characterized by being equipped with.