JPH03104888A - Plasma device - Google Patents

Abstract

PURPOSE:To prevent the crack of transmission windows by the heat of plasma by dividing the microwave transmission window for heat resistance disposed in proximity to the microwave transmission window for holding vacuum to plural constituting parts whose boundaries are brought into contact with the plasma. CONSTITUTION:Microwaves are introduced from a waveguide 2 through the transmission windows 3, 4 into a plasma forming chamber 1 to convert the gas introduced therein to the plasma in the plasma forming chamber 5 maintained under reduced pressure. A substrate is worked by the formed plasma 6. The microwave transmission window 4 for heat resistance made of alumina, etc., whose one surface is exposed in the plasma forming chamber 5 of the above-mentioned plasma device, is divided to the plural constituting parts 4a, 4b and is so formed that the greater part of the boundaries on which these parts are abutted covers the plasma 6 contact region. The microwave transmission window 3 for holding vacuum consisting of one sheet is provided in proximity to the upper part of the above-mentioned microwave transmission window 4 for heat resistance to avert the generation of the plasma in the spacing between both and to hermetically isolate the waveguide 2 from the plasma forming chamber 1. Thus, the generation of the crack in the two transmission windows 3, 4 is obviated even if the windows are heated by the plasma 6.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of a plasma device for processing semiconductor devices using plasma generated under reduced pressure by microwaves, the transmission window made of aluminum does not crack even when heated. The purpose of the present invention is to provide a plasma generation chamber that generates plasma by introducing gas and microwaves, and a plasma generation chamber in which most of the exposed and abutting interfaces are in contact with the plasma. A heat-resistant microwave-transmitting window divided into a plurality of control parts so as to span the area, and a vacuum-maintaining window provided close to the heat-resistant microwave-transmitting window to prevent plasma from being generated in the gap between the windows. It is configured to include a microwave transmission window and a waveguide that is airtightly isolated from the plasma generation chamber by the vacuum-maintaining microwave transmission window and that supplies microwaves into the plasma generation chamber.

[Industrial application field]

The present invention relates to an improvement in a plasma apparatus for processing semiconductor devices using plasma generated under reduced pressure by microwaves.

As the miniaturization of semiconductor devices progresses, various devices have been realized that use plasma generated under reduced pressure by microwaves to process the devices.

That is, for example, a microwave plasma ashing device,
Microwave plasma etching equipment, microwave plasma down flow ashing equipment, microwave plasma down flow etching equipment, microwave plasma down flow dry developing equipment, etc. are known. The device is about to be used extensively.

Therefore, it is important to ensure that each of these devices can operate smoothly without any failures. [Prior Art] In general, among plasma devices that process semiconductor devices using plasma generated under reduced pressure by microwaves, when a gas containing fluorine such as CF4 is used as the plasma generating gas, Quartz cannot be used as a microwave transmission window. The reason for this is that quartz is etched by fluorine-containing plasma generated near the transmission window. Therefore, alumina (Afz 03
) is used.

[Problem to be solved by the invention]

Plasma devices that use alumina for the microwave transmission window mentioned above have lower heat resistance than those made of quartz, and often crack during operation, which increases the time it takes to replace the window. This creates a problem in that the operating rate decreases.

The present invention aims to provide a plasma device in which a transmission window made of alumina does not break even when heated.

[Means to solve the problem]

In the plasma device according to the present invention, there is provided a plasma generation chamber (for example, plasma generation chamber 1) in which gas and microwaves are introduced to generate plasma, and an interface that is exposed on one side of the plasma generation chamber and abuts against the plasma generation chamber. A heat-resistant microwave-transmitting window (e.g., heat-resistant microwave-transmitting window 4) divided into a plurality of component parts (e.g., structural parts 4A and 4B) so that most of the window covers the plasma contact area; A vacuum-maintaining microwave-transmitting window (e.g. vacuum-maintaining microwave-transmitting window 3) provided close to the wave-transmitting window so as not to generate plasma in the gap between the vacuum-maintaining microwave-transmitting window and the vacuum-maintaining microwave-transmitting window. A waveguide (for example, waveguide 2) is provided, which is airtightly isolated from the plasma generation chamber and supplies microwaves into the plasma generation chamber.

(Function) By adopting the above method, even if the heat-resistant microwave transmission window is heated by plasma, the expansion and contraction can be absorbed by each structural part, so that they will not break and the vacuum Since the holding microwave transmission window is isolated from the plasma by the heat-resistant microwave transmission window, there is no risk of cracking in this window either. Able to master the precepts well.

[Embodiment] FIG. 1 shows a cutaway side view of the essential parts of an embodiment of the present invention, and FIG. 2 shows a plan view of the essential parts of the sixth embodiment shown in FIG. 1.

In the figure, 1 is a plasma generation chamber, IA is a cooling water flow path,
2 is a waveguide, 3 is a vacuum-maintaining microwave-transmitting window, 4 is a heat-resistant microwave-transmitting window, 4A and 4B are constituent parts of the heat-resistant microwave-transmitting window 4, 5 is a plasma generation chamber under reduced pressure, Reference numeral 6 indicates the plasma, and 7 indicates the plasma contact area.

As is clear from the figure, in this embodiment, the vacuum-maintaining microwave-transmitting window 3 is formed of a single plate, and the heat-resistant microwave-transmitting window 4 is divided into two component parts 4A and 4B.

Furthermore, since the microwave transmission window 3 is for maintaining vacuum, the plasma generation chamber 5 should be
The microwave transmitting window 4 plays the role of clearly separating the two sides from each other, but the microwave transmitting window 4 also plays the role of preventing the microwave transmitting window 3 from cracking due to heating by plasma, and prevents the microwave transmitting window 3 from expanding or contracting. In order to improve the resistance to damage, it is divided approximately at the center into constituent parts 4A and 4B as shown in the figure. The microwave transmission window 4 may be divided into even more parts if the supporting means are appropriately selected.
In any case, the main dividing line, i.e. components 4A and 4B
The key to improving the resistance to cracking is that the abutting interface with the plasma contact area 7 extends over the plasma contact area 7. Furthermore, the microwave transmission window 3 allows the plasma 6 to e.g.
Even if it is made of F4, it is not directly touched, so it may be made of quartz to improve heat resistance.

〔Effect of the invention〕

In the plasma device according to the present invention, there is a plasma generation chamber that generates plasma by introducing gas and microwaves, and a plasma contact area in which most of the interface that is exposed to the plasma generation chamber and abuts against each other is a plasma contact area. A heat-resistant microwave transparent window divided into multiple component parts so as to hang over the
A vacuum-maintaining microwave-transmitting window is provided in close proximity to the heat-resistant microwave-transmitting window so as not to generate plasma, and the vacuum-maintaining microwave-transmitting window is airtight with the plasma generation chamber. and a waveguide which is isolated and supplies microwaves into the plasma generation chamber.

By adopting the above-mentioned precautions, even if the heat-resistant microwave transmission window is heated by plasma, each component can absorb the expansion and contraction, so it will not break. Since the wave-transmitting window is isolated from the plasma by the heat-resistant microwave-transmitting window, there is no risk of cracks occurring there either, thus achieving good airtight separation between the plasma generation chamber side and the waveguide side. can do.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of an essential part of an embodiment of the present invention, and FIG. 2 is a plan view of an essential part of the embodiment shown in FIG. In the figure, 1 is a plasma generation chamber, IA is a cooling water flow path,
2 is a waveguide, 3 is a vacuum-maintaining microwave-transmitting window, 4 is a heat-resistant microwave-transmitting window, 4A and 4B are constituent parts of the heat-resistant microwave-transmitting window 4, 5 is a plasma generation chamber under reduced pressure, Reference numeral 6 indicates the plasma, and 7 indicates the plasma contact area. Main part cutaway side view of one embodiment of the present invention FIG. 1 FIG. 2

Claims (1)

[Scope of Claims] A plasma generation chamber that generates plasma by introducing gas and microwaves; a heat-resistant microwave-transmitting window divided into component parts; a vacuum-maintaining microwave-transmitting window provided close to the heat-resistant microwave-transmitting window so as not to generate plasma in the gap between the heat-resistant microwave-transmitting window; A plasma device comprising: a waveguide airtightly isolated from the plasma generation chamber by a vacuum-maintaining microwave transmission window and supplying microwaves into the plasma generation chamber.