JPH0350723A - Plasma etching device - Google Patents

Abstract

PURPOSE:To prevent the adhesion of a gas and a reaction product to a view port by providing a temperature regulating means at the view port in a plasma etching device. CONSTITUTION:Heaters 16 are provided at the wall of a vacuum vessel 1 and the temperature of a vacuum vessel wall is regulated. The temperature regulation of a view port 9 is performed by using an electric heating alloy wire 19 which is held by a view port holder 18 and is embedded in silica glass 17. In such a case, the temperature of its port is regulated so that the view port may have the same temperature as that of the vacuum vessel wall.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma etching apparatus, and more particularly to the structure of a viewing window.

[Conventional technology]

Conventionally, plasma etching equipment used in the manufacture of semiconductor devices creates a high vacuum in a vacuum chamber, then introduces etching gas into the vacuum chamber to face supporting electrodes on which the wafer is placed. A high frequency (e.g. 13
．． 56MHz) is applied to generate plasma between the electrodes, and the film to be etched is etched through a physical reaction caused by ion bombardment in the gas plasma and a chemical reaction caused by the active gas. (hereinafter referred to as a view boat), the plasma discharge state and etching state were confirmed.

[Problem to be solved by the invention]

In the conventional plasma etching apparatus described above, the electrode and the vacuum vessel are provided with a temperature control mechanism, but the view boat is not equipped with a temperature control means and cannot be heated. There is a disadvantage that a large amount of reaction products adhere to this view boat, which peels off and becomes a source of dust. In addition, when using the view boat as a window for an endpoint detector, the signal intensity of the light emitted from the plasma in the vacuum chamber decreases due to large amounts of gas and reaction products adhering to the view boat, causing the endpoint to It has the disadvantage of being unclear. This large amount of gas and reaction products adhere to the view boat because the temperature of the view boat is low, so that the gas and reaction products adsorbed on the surface cannot be removed and remain.

The present invention differs from the conventional plasma etching apparatus described above in that it includes a view boat with temperature control means. Therefore, it becomes possible to heat the view boat, and it is possible to prevent gas and reaction products from adhering to the view boat.

[Means to solve the problem]

The plasma etching apparatus of the present invention includes a support electrode provided in a vacuum container on which a semiconductor wafer is placed, a counter electrode provided opposite to the support electrode, and a gas inlet provided in the vacuum container. The plasma etching apparatus has a gas exhaust port and a peephole, and the peephole is provided with temperature control means.

〔Example〕 Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic sectional view of an embodiment of the present invention, and FIG. 2(a)
, (b) are a front view and a sectional view of a view boat with a temperature control means used in an embodiment of the present invention.

A pair of electrodes, namely an anode 2 which is a counter electrode and a cathode 3 which is a support electrode on which a wafer 4 is placed, are provided facing each other in the vacuum container 1 while being electrically insulated by an insulating member 6. . A high frequency power source 15 is connected to the cathode 3 via a matching box 14. Further, the anode 2 is grounded. There is an etching gas exhaust lower directly connected to a rotary pump 13 and a mechanical booster pump 12 to evacuate the inside of the vacuum container 1, and the inside of the vacuum container 1 is evacuated by opening the gate valve 10.
Further, the temperature of the anode 2 and cathode 3 is controlled by a temperature regulator 11. Further, a heater 16 is provided on the wall of the vacuum container 1 to control the temperature of the wall of the vacuum container. Note that 5 is a gas introduction port for introducing a reaction gas. The temperature of the view boat 9 is controlled by an electric heating alloy wire 19 held in a view boat holder 18 and embedded in a quartz glass 17, as shown in FIG. At this time, the temperature of the view boat is controlled so that the temperature of the view boat is the same as the temperature of the wall of the vacuum vessel.

According to this embodiment configured in this manner, the view boat 9 is heated in the same way as the wall of the vacuum vessel 1, so that the adhesion of gas and reaction products is extremely small.

The temperature of the view boat can also be controlled by introducing heated dry air 20 between two sealed quartz glasses 17, as shown in FIGS. 3(a) and 3(b). good.

〔Effect of the invention〕

As explained above, the present invention has the effect of preventing gases and reaction products from adhering to the observation window by providing a temperature control means in the observation window of the plasma etching apparatus.

Therefore, the generation of dust from deposits is eliminated, making it possible to improve the yield. Furthermore, since it is possible to prevent a decrease in the luminous intensity obtained from the plasma in the vacuum container, it is possible to obtain endpoint operation of the endpoint detector with good reproducibility over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, and FIG. 2(a)
, (b) and FIGS. 3(a) and 3(b) are a front view and a sectional view of a view boat used in an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Vacuum container, 2... Anode, 3... Cathode, 4... Wafer, 5... Gas inlet, 6... Insulating member, 7... Etching gas exhaust port, 8 ... Endpoint detector 9 ... View boat, 10
... Gate valve, 11 ... Temperature controller, 12 ... Mechanical booster pump, 13 ... Rotary pump, 14 ... Matching box, 15 ... High frequency power supply, 16.
... Heater, 17... Quartz glass, 18... One view boat holder... Alloy wire for electric heating, 20...
Heated dry air, 21... Heated dry air inlet, 2 2... Heated dry air exhaust port.

Claims (1)

[Claims] A supporting electrode on which a semiconductor wafer is placed, provided in a vacuum container, a counter electrode provided opposite to the supporting electrode, and a gas inlet, a gas exhaust port, and a peephole provided in the vacuum container. What is claimed is: 1. A plasma etching apparatus comprising: a temperature control means provided in the observation window;