JPS5976876A - Method and device for reactive ion etching - Google Patents

Abstract

PURPOSE:To improve selectivity and productivity by performing etching of a material to be etched at >=2 different electrode temps. CONSTITUTION:A vacuum vessel 11 is installed therein with an etching electrode 12 and an overetching electrode 13 insulated electrically from said vessel and the electrodes 12, 13 are provided respectively with high-frequency electrodes 15, 16 and temp. controllers 17, 18 controlling the temp. thereof. A substrate 14 to be etched is first brought by a conveyance mechanism into the vessel 11 from the outside, and is placed on the electrode 12 controlled to about 60 deg.C by the controller 17, whereby the substrate is etched. The substrate 14 is then moved, and is placed on the electrode 13 controlled to about 30 deg.C by the controller 18, whereby the substrate is etched.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a reactive ion etching method and a reaction that can improve its selectivity and productivity, as well as suppress the occurrence of overhang phenomena. This paper describes a method and apparatus for etching ions.

[Technical background of the invention and four points]

Generally MoSi. The film is one of the high-melting point metal silicides that is highly sought after and extensively researched as a material for electrodes and wiring in VLSIs. This Mo El12-
(Since the first place is used for super L6! ■, it naturally has to be microfabricated, and the applicant of this application
We have been researching and developing etching (hereinafter simply referred to as etching) using this Mo81□mt reactive ion etching method for a long time. We have been examining the process of etching.

By the way, when using this method, the vapor pressure of Mo 01s is very high. M[strongly dependent, 40t, 'pig t when changed! l (The exposure pressure changes by a factor of 1. In other words, when etching is performed with the upper punch at a temperature of the substrate to be etched, the first
As shown in the graph of the figure, the etching speed of Mo81□ changes in large steps. On the other hand, since the etching speed of the resist, which should be the key during etching, is
From the viewpoint of etching selectivity between MoE11□ and resist and productivity, it is considered desirable to perform etching at a tougher temperature of the substrate to be etched. So, Honkawa h? When I etched the substrate myself by raising the temperature, it was confirmed that both the selectivity and productivity were improved.

However, it has been found that when over-etching is performed, an overhang phenomenon occurs in the MOSi2 film, as shown in FIG. That is, in FIG. 2, l is the substrate, 2l-It is the MoSi□ film as the former to be etched, and 8 is the resist, which is a resist. It shows an overhang phenomenon that protrudes forward.

It has been confirmed that such an overhang phenomenon appears more conspicuously as the temperature of the substrate l becomes higher, and that it hardly occurs when the substrate temperature is lowered by V+.

In this way, from the viewpoint of selectivity and productivity, it is necessary to raise the substrate temperature, but from the viewpoint of overhang, it is necessary to lower the substrate temperature, which contradicts each other and requires swirl reliability. Ru.

[Purpose of the invention]

In view of these points, the present invention provides a reactive ion etching method and apparatus thereof, which can improve selectivity and productivity, and can effectively prevent the occurrence of overhangs and cavities. The purpose is to

[Summary of the invention]

This object is achieved according to the invention by etching the material to be etched at two or more different electrode temperatures.

[Embodiments of the invention]

FIG. 3 shows a first embodiment of the present invention, in which an etching electrode 12 and an over-etching electrode 13, which are electrically insulated from the container 11, are installed in a vacuum chamber 11. A substrate 14 to be etched is placed on the substrate 12.13. Also, each electrode 12.13 is equipped with a high frequency power source 15.16 and a temperature controller 17%18 for controlling the temperature of each electrode 12.13. The substrate to be etched 14 is first transferred to a transport mechanism (not shown) for etching at high temperature f4 (4, 4, 4).
The film is placed on the Qi 12 and subjected to etching, and then transferred to the over-etching device t13 for over-etching.

Next, the operation of the above-described embodiment will be explained.

During etching, the substrate 14 to be etched is first taken into the vacuum chamber 11 from the outside by a transport mechanism (not shown) and placed on the temperature-controlled etching electrode 12. % MoS 127g (thickness 11 is 90
Etch %.

Next, move the substrate 14 to be etched,
It is placed on the overetching electrode 13 whose CK heating is controlled and overetching is performed to complete the etching process.

According to such an embodiment, since pressure is applied to over-etch at a low electrode temperature after etching at a high electrode temperature, it is possible to improve the etching selectivity of MoSi and resin and productivity. What's more, the overhang phenomenon that occurs in the Maxi□ membrane is effectively prevented! can be

In the above embodiment, one etching electrode 12 was provided for one overetching electrode, but the number of etching electrodes 12 was changed so that the etching time and overetching time could be balanced. You can increase it.

FIG. 4 shows a second embodiment of the present invention, in which an electrode 19 on which a plate to be etched 14 is placed on the upper surface 1) 1q of the vacuum chamber 11 is electrically isolated from the chamber 11. It is priced with a border. As shown in the figure, this electrode 19 is equipped with a high-frequency electric current fM20, a temperature controller 21 that controls the temperature of the electrode 19 to 60C, and a temperature regulator 22 that controls the temperature of the electrode 19 to 3()C. and
Both temperatures are 0 [regulator 21.22, three-way cock 23°2]
It is a trap that can be switched from 4 traps.

Next, the operation of the above-described embodiment will be explained.

At the time of etching, the three-way cocks 23 and 24 are swept, and the temperature of the electrode 19 is controlled to 60C by the 1-piece 21. Then, the material to be etched 14 is placed on this electrode 19 by a transport mechanism (not shown).

The I part of the MO8i, . . .
24 to the temperature controller 22 side and set the temperature to 30'C.
Geo-bar etching is performed at a temperature of 19 to complete the etching process. The graph in Figure 5 looks like this
1.

Also, in the case of one actual fiiHi example, it is possible to achieve the same etching selection ratio and productivity of MoSi□ and resist as in the first embodiment described above, and the improvement of productivity = 1.
1) Overhang phenomenon occurring in the film can be effectively prevented.

〔Effect of the invention〕

As explained above, the present invention etches at two or more different electrode temperatures, so MoSi□
The etching selectivity and productivity of the resist can be improved, and the overhang phenomenon occurring in the MOSi2 film can be completely prevented.

[Brief explanation of the drawing]

Figure 1: MoSi subjected to reactive ion etching method
. A graph showing the relationship between the etching speed of 1 and 4, and the εB2 diagram is MoSi. 3 and 4 are cross-sectional views showing embodiments of the present invention, respectively. It is a graph showing the relationship with temperature. 1''...A empty container, 12...Etching' electrode, 1
3... Over-etching electrode, pole, 14... Material to be etched, 17.18.21.22... Temperature controller, 19... Electrical rating, 23.24... Three-way cock. Applicant's agent Kiyoshi Inomata Figure 1 Electric Glaze Haruka 71L ('C) Figure 2

Claims (1)

[Claims] l) A material to be etched is placed on an electrode placed in a reactive gas, and a voltage is applied to this electrode to cause a gas discharge, so that N+3 material to be etched is placed before being exposed to the discharge gas. In the reactive ion etching method for etching the material,
11. A reactive ion etching method characterized in that the etching target is etched at two or more different electrode temperatures. 2) A reactive ion etching method according to claim 1, characterized in that the material to be etched is etched at a high electrode temperature and then over-etched at a low electrode temperature. 3) A reaction in which the material to be etched is placed on the upper end of the electrode in a reactive gas, and a voltage is applied to the t-electrode of the electrode to cause discharge, and the material to be etched is etched by this discharge gas. In the ion etching apparatus, the material to be etched is etched at two or more different temperatures.
(A reactive ion etching device characterized by having an electrode structure capable of etching. 4) A patent characterized in that the electrode is composed of a plurality of electrode bodies, and the temperatures of the electrode bodies are made to be different from each other. Reactive ion etching according to claim 3. 5) A reactive ion etching apparatus according to claim 3, characterized in that the temperature of the electrode can be adjusted according to the etching process.