JPS59177931A - Microwave processor - Google Patents

Abstract

PURPOSE:To remove heat radiated from a microwave processor, and to prevent a magnetron, etc. from curtailment of usable life by a method wherein the antenna of the microwave generator is arranged in a waveguide, and gas is flowed in the waveguide to cool the antenna. CONSTITUTION:A cooling gas feed port 14 is provided in a side wall near the chamber 1 of a waveguide 2, a cooling gas exhaust port 13 is provided at an edge face of the side provided with a magnetron 3, and moreover a gas circulating pipe 12 to pass outside of a microwave processor is arranged between the cooling gas feed port 14 and the exhaust port 13 thereof. For example, nitrogen gas is circulated as cooling gas in the order of a cooler 10, a compressor 11, the cooling gas feed port 14, the waveguide 2, the cooling gas exhaust port 13, and to the cooler 10 again. Accordingly, the antenna 4 of the magnetron 3 can be cooled directly by the nitrogen gas.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a microwave processing apparatus that performs plasma etching and the like by generating activated gas by irradiation with microwave power.

(2) Background of the technology Microwave processing (for example, etching), which uses microwaves to heat a workpiece and generate plasma, is a mainstream technology in recent manufacturing of high-density semiconductor integrated circuits.

FIG. 1 is a diagram showing the configuration of a microwave processing device (1) that performs the above-mentioned microwave processing, and an antenna 4 for emitting microwaves generated by a microwave generator (magnetron) 3 is arranged at the internal end. The waveguide 2 having a rectangular cross section is connected to a chamber 1 for performing microwave processing via a window 7 formed of an insulator such as quartz. The chamber 1 is provided with an inlet 8 and an exhaust port 9 for processing gas, and a workpiece (for example, a wafer) 6 is placed therein.

Further, the waveguide 2 is provided with a tuner 5 that adjusts the microwaves so that reflection is minimized and microwaves are efficiently absorbed.

In a device having such a configuration, microwaves emitted from the antenna 4 propagate within the waveguide 2, pass through the window 7, and are irradiated into the chamber 1. On the other hand, a processing gas (for example, Freon gas, CF gas) is introduced into the chamber 1 through the gas introduction port 8, is turned into plasma by the microwave irradiation, and various processing is performed. Note that the pressure inside the chamber 1 is constantly reduced by an exhaust device (not shown) connected to the exhaust port 9.

(2) (3) Prior Art and Problems By the way, in the above-mentioned microwave device, the heat generated in the chamber 1 during processing is transmitted through the metal waveguide 2, and is transmitted through the antenna 4 and the magnetron through it. It has been experienced that 3 is heated to a higher temperature than necessary.

Conventionally, the magnetron 3 is provided with a cooler (not shown) in order to prevent the antenna 4 and the magnetron body from being heated by the heat generated by the magnetron itself. However, this cooler does not have the ability to remove the heat generated by the magnetron itself, so it cannot deal with the heating caused by the heat transmitted from the chamber 1. As a result, the magnetron 3 and antenna 4 become abnormally high in temperature, resulting in a problem that their service life is shortened.

In addition, due to the heat transmitted through the waveguide 2, the chamber 1 and the waveguide 2
The reaction between the processing gas and the O-ring (not shown) provided on the connection surface of the window 7 and the insulating material forming the window 7 will be accelerated, damaging the O-ring and the window 7 and preventing airtightness. There are also problems such as not being able to hang out.

(3) (4) Purpose of the Invention In view of the above-mentioned conventional problems, the present invention provides microwave treatment that removes heat emitted from a chamber through a waveguide and prevents shortening of the service life of magnetrons, etc. The purpose is to provide equipment.

(5) Structure and object of the invention According to the present invention, in an apparatus for microwave processing, an antenna of a microwave generator is disposed in a waveguide, and a gas is caused to flow in the waveguide. This is achieved by providing a microwave processing device characterized by having a configuration that cools the antenna.

(6) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram of a microwave processing apparatus for explaining an embodiment of the present invention, and in this figure, the same parts as in FIG. 1 are designated by the same reference numerals. Referring to FIG. 2, the cooling gas supply port 14 is provided on the side wall of the waveguide 2 near the chamber 1, and the cooling gas discharge port 13 is provided on the end face on the side where the magnetron 3 is provided. Between the cooling gas supply port 14 and the discharge port 13, for example, an inner diameter of about 3+n passes through the outside of the microwave processing device.
m gas circulation pipes 12 are provided. A cooler 10 and a compressor 11 are provided in the middle of the gas circulation pipe 12.

The cooling gas supply port 14 and the discharge port 13 have a diameter of 2 to 3 mm and are formed so as not to absorb microwaves.

In such a configuration, for example, nitrogen gas (N
2) to the cooler 10. The gas is circulated in the order of the compressor 11, the cooling gas supply port 14, the waveguide 2, the cooling gas discharge port 13, and again the cooler. Nitrogen gas is cooled to, for example, room temperature or lower in a cooler 10, then compressed in a compressor 11, and injected into the waveguide 2 from a supply port 14 at a pressure of about 1 kg/cm2. The injected nitrogen gas flows toward the exhaust port 13 while absorbing heat within the waveguide 2, is sent from the exhaust port to the cooler 10, and the above-described circulation is repeated.

Moreover, nitrogen gas has no effect on the propagation of microwaves.As mentioned above, nitrogen gas
) Since the antenna 4 of the magnetron 3 can be directly cooled, shortening of the life of the magnetron 3 can be prevented.

The inventor of the present application has confirmed that the life of the magnetron, which was conventionally 800 hours, can be extended to about 1000 hours under the conditions shown in the above examples.

Note that the cooling gas is not limited to the above-mentioned nitrogen gas, and the effects of the present invention will not be impaired in any way even if other gases, such as air, are used. Further, the temperature and pressure of the cooling gas are not limited to the above values, and are appropriately selected depending on the form of microwave processing.

According to the cooling means, damage to the insulator of the window 7 and the O-ring disposed between the waveguide 2 and the chamber 1 can also be prevented.

(7) Effects of the Invention As explained in detail above, according to the present invention, a microwave processing device can prevent shortening of the service life of the magnetron and other device components due to heat by flowing cooling gas into the waveguide. As a result, equipment maintenance is easier than before, which has a great effect on semiconductor (6) equipment productivity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional microwave processing apparatus, and FIG. 2 is a block diagram of a microwave processing apparatus according to the present invention. 1-Chamber, 2-Waveguide, 3-Magnetron, 4-Antenna, 5-Tuner, 10-Cooler, 11-Combresozer, 12-Cooling gas circulation pipe (7) Fig. 1 Fig. 2

Claims (1)

[Claims] An apparatus for microwave processing, characterized in that an antenna of a microwave generator is disposed within a waveguide, and the antenna is cooled by flowing gas within the waveguide. Device.