JPS594849B2 - Microwave plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in microwave plasma processing equipment used for pattern formation and the like when forming semiconductor devices.

In general, plasma processing apparatuses are becoming indispensable for manufacturing integrated circuit devices from the viewpoint of forming various fine patterns and dry processes.

In particular, when plasma is excited with microwaves, a stable, high-density plasma can be obtained at a wide range of gas pressures, from low to high pressures, compared to when excited with radio frequencies.

For example, when plasma is excited with a high frequency of 13.56 [MH2], the density of plasma particles is ~109 [1-degree], but when excited with microwaves of 2.45 [GH2], the density is ~010"" [1-゜]. By the way, in such a microwave plasma processing apparatus, a processing chamber shaped like a bell shear, into which a semiconductor wafer is inserted, is installed in a cavity to which microwaves are supplied, and plasma is introduced into the processing chamber. The patent application filed by the same applicant in 1984-16
No. 8097 (see Japanese Patent Publication No. 57-19567).

In this equipment, since the inside of the processing chamber must be maintained at a reduced pressure, two pipes, an exhaust pipe and a gas supply pipe, are installed in the processing chamber, and a gas supply pipe is used to load and unload semiconductor wafers. The structure is such that a cover plate is removably disposed on the abrasive surface. The cover plate is adapted to be airtightly attached to the main body. According to this device, plasma is generated in the processing chamber and microwaves are supplied throughout the processing chamber, so it is possible to raise the temperature of the semiconductor wafer, and therefore it is possible to raise the temperature of the semiconductor wafer. It is possible to etch not only silicon but also insulating films such as silicon dioxide. 30 Table 1 is reproduced from the specification of the above-mentioned application in order to explain the effects of this device, and shows that this device and ordinary high frequency (13.56M)
H2) This is a comparison of processing speeds when a similar etching process is performed using a plasma etching device and a commercially available microwave plasma etching device.

Incidentally, in a processing chamber, both the main body and the cover plate are usually made of quartz, and in that case, some kind of packing is essential to connect the two airtightly. As such packing, an elastic material such as rubber is generally used. However, since the above-mentioned type of apparatus has a structure similar to that in which the processing chamber is disposed inside a microphone-mouth wave electronic oven, the packing, which is mostly made of dielectric material, becomes extremely hot. Therefore, conventionally, packing materials such as fluorine-based rubber have been used that have high heat resistance, but even then, the packing material deteriorates when the temperature exceeds 250 C'C, resulting in a decrease in airtightness. Various other materials can be considered from the standpoint of heat resistance and heat resistance, but since materials that contaminate the semiconductor wafer must be avoided, material selection is severely restricted in this respect. As described above, it has become clear that in the conventional apparatus, since microwaves are supplied to the entire processing chamber, there is an inconvenience that the packing deteriorates. The present invention is an attempt to solve the problems of the prior art, and is a microwave plasma processing method in which a processing chamber is placed inside a cavity to which microwaves are supplied, and plasma is generated inside the chamber. The purpose of the present invention is to provide a microwave plasma processing apparatus that has an extremely simple configuration and prevents deterioration due to temperature rise of the packing that maintains airtightness between the main body and the lid of the processing chamber, and this will be described in detail below. explain.

The figure is a schematic explanatory diagram of one embodiment of the present invention.

In the figure, 1 is a processing chamber cover made of quartz, 2 is an exhaust pipe, 3 is a gas supply pipe, 4 is a lid plate, and 5 is an O (O1), for example.
6 is a packing ring, 6 is a semiconductor wafer to be processed, 7 is a cooling gas outlet, 8 is a cavity, and 9 is a microwave antenna.

In the heat exchanger, the inside of the processing chamber is evacuated through the exhaust pipe 2 to create a predetermined vacuum, and then processing gas is supplied through the gas supply pipe 3 to maintain the predetermined gas pressure (depressurization) in the processing chamber. 2.45 (GHz) generated by a microwave generator (not shown).
) is sent into the cavity chamber 8 from the antenna 9, gas and plasma are generated in the processing chamber, which is composed of the heather 1 which is hermetically sealed with the lid plate 4 and the packing 5, and the semiconductor wafer 6 is heated. Plasma treatment is performed.

During this time, an inert cooling gas such as nitrogen or argon is sent out from the cooling gas blowing section 7 towards the packing 5 and its vicinity to cool that part. Therefore, the increase in depth of the packing 5 is suppressed to a low level, and no deterioration occurs. Next, data related to this example will be listed.

(1) Microwave power 600W, argon gas 0.5T
When argon plasma was generated under the condition of 0 rr, the O-ring made by Viton was seized approximately 5 minutes after the plasma was generated. However, when plasma is generated under the same conditions, if nitrogen gas is sprayed on the O-ring at a rate of 101/1 to cool it down, 2
No seizure occurred for more than 0 minutes. Incidentally, when the Viton rubber (fluorine-based rubber) is burned, fluorine is generated, which has an adverse effect on plasma processing.

(2) When using a silicone rubber O-ring under the same conditions as in (1) above, the O-ring melted in about 2 minutes and could no longer be removed, but when similarly cooled with nitrogen gas,
Even after plasma treatment for 0 minutes, no deterioration of the O-ring occurred. As can be seen from the above explanation, according to the present invention, in a microwave plasma processing apparatus in which a processing chamber is arranged in a cavity chamber to which microwaves are supplied and plasma is generated inside the processing chamber, processing can be performed. The processing chamber is composed of the chamber main body and a lid plate that is airtightly attached to the chamber body through packing, and a cooling gas blowing section is provided for blowing cooling gas into the packing and its vicinity, so that the processing chamber can be turned into a hollow chamber. Even when the packing is inserted and operated to generate plasma, the temperature rise in the packing is suppressed to a low level, so it does not deteriorate and can effectively maintain airtightness over a long period of time.

[Brief explanation of drawings]

The figure is a schematic explanatory diagram of main parts of an embodiment of the present invention.

Claims (1)

[Claims] 1 In a microwave plasma processing apparatus in which a processing chamber is arranged in a cavity chamber to which microwaves are supplied and plasma is generated inside the processing chamber, the processing chamber main body and a lid that is airtightly attached to the processing chamber body via packing are used. a processing chamber having a plate, a cooling gas blowing section arranged to blow cooling gas onto the packing of the processing chamber and its vicinity, and a cooling gas blowing section that accommodates the entire processing chamber and the cooling gas blowing section and to which microwaves are supplied. A microwave plasma processing apparatus characterized by comprising a cavity chamber.