JPS59150534A - Ion beam etching apparatus - Google Patents

Abstract

PURPOSE:To enable etching treatment generating no contamination, by providing a cover member low in a sputtering yield or a member containing no heavy metal to a part at least directly irradiated with ion beam. CONSTITUTION:In an apparatus wherein the ion beam generated from an ion source 8 is supplied to an etching treatment chamber 10 and etching treatment due to sputtering is performed while said beam is collided with the surface of a specimen, cover members 12, 13 low in a sputtering yield or members each containing no heavy metal for exerting a serious influence on the specimen are provided to parts each at least directly irradiated with ion beam such as the inner wall of the treatment chamber 10 and a substrate holder 11. As the material of each cover member, alumina, titanium carbide or silicon carbide are used. As a result, sputtering on the inner wall of the treatment chamber or the substrate holder and dissipation of ion beam and an atom or an ion from the wall material or the substrate holder material are prevented and etching treatment free from contamination is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an ion beam etching apparatus which accelerates an ion beam generated in an ion source, supplies it to an etching processing chamber, and pressurizes the ion beam so that it collides with a sample surface to perform etching processing by sputtering. It is related to.

With the miniaturization of semiconductor devices, technologies such as ion beam etching with excellent microfabriability and controllability, and reactive ion beam etching (hereinafter simply referred to as ion beam etching) with even greater selectivity have become available. It is starting to be used.

However, in ion beam etching used for processing semiconductors, metal, which is the material of the vacuum chamber forming the processing chamber, adheres to the substrate, causing a problem of contamination. Particularly in the fabrication of VLSI devices, metal contamination occurring during ion beam etching is a major problem. For this reason, conventional ion source chambers have been proposed in which the inner wall surface of the ion source chamber is coated with an insulating material so that a highly pure ion beam can be extracted. However, even if an ion source capable of extracting such a high-purity ion beam is used, the beam diameter of the ion source used for etching is large, and the opening of the extraction electrode is also large, so the inside of the ion source may be affected. To prevent contamination, the ion beam collides not only with the substrate but also with its holder and the inner wall of the vacuum chamber, causing atoms and ions to be emitted from the substrate holder material and the vacuum chamber wall material, etc., which adhere directly to the processing substrate. It is thought that a larger proportion of the ions are diffused back into the ion source and then re-emitted, causing contamination on the substrate.

Therefore, it is not possible to substantially solve the problem of substrate surface contamination from the wall material of the substrate vacuum chamber in ion beam etching by using only the conventionally known ion source capable of generating ion beams of high purity as described above. Can not.

As shown in FIG. 1, in a conventional ion etching apparatus, the walls of the processing chamber and the substrate holder are usually made of SUS.For example, in FIG. Ar ion beam extracted from = by extraction electrode l
8+ Considering the case of etching the substrate 6, the Ar ion beam j from the ion source 3 has a spreading force (arrow! a), and also collides with the residual gas before reaching the substrate 6 [arrow jl] ), in addition to those that directly collide with the 8i substrate B, there are also those that collide with the inner wall of the processing chamber L. As a result, these ion beams ja,t
b collides with the inner wall of the processing chamber l, and atoms and ions of the SUS wall material are ejected due to splattering. As a result, not only the extraction electrode plate (Mo, etc.) of the ion source 7 is coated with the SUS of the substrate holder and wall material, but also the SUS materials Fe, Ni, and O are coated inside the ion source 3.
r enters and causes pollution. Therefore, in ion beam etching apparatuses, contamination by processing chamber walls and substrate holder materials is a serious drawback.

Therefore, an object of the present invention is to prevent the process chamber walls and substrate holder materials from being splattered by the ion beam and release atoms and ions from the wall materials and substrate holder materials, and to perform etching without contamination. To provide an ion beam etching device that enables processing.

For this purpose, the ion beam etching apparatus according to the present invention includes a small covering member with a snow groove ring P or a member that does not contain heavy metals on at least the portion directly irradiated with the ion beam, such as the inner wall of the etching processing chamber or the substrate holder. It is characterized by having the following. For this covering material, Carzen (graphite) Sin, Alumina, Titanium car/? Examples of the material include carbon fiber, silicon carbide, etc., but the material is of course not limited to these materials, and can be appropriately selected from materials with a small snogging yield. This covering member can be formed as a surface covering layer of the part directly irradiated with the ion♂-me, and the covering member can be configured in a plate shape.
It may be attached to the inner wall of the processing chamber or the surface of the substrate holder, etc.
In this case, for example, a plate-shaped cover member can be placed around the processing substrate so as to cut off the ion beam directed toward the inner wall of the processing chamber.

According to another feature of the present invention, at least the portion directly irradiated with the ion beam, such as the inner wall of the etching processing chamber or the substrate holder, is constructed of a member having a small snogging yield as described above.

Therefore, it is possible to prevent contamination by applying a material with a small snogging yield to the walls of the etching process chamber, the substrate holder, etc. that are directly irradiated with the ion beam, or by forming the above-mentioned parts themselves with such materials. (as a result, contamination-free processing is possible), and the good processing accuracy of ion beam etching can be utilized.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to Figures 1 to 3 of the accompanying drawings.

FIG. 2 shows an embodiment of an ion beam etching apparatus according to the present invention, which includes an ion source r of any suitable type, an extraction electrode, a vacuum chamber io forming an etching processing chamber, and a vacuum chamber io forming an etching processing chamber. Substrate holder l accommodated in tank lO
It consists of l.

In this embodiment, the inner wall of the processing chamber IO and the substrate holder
A covering member made of, for example, Kazen (electroconductive graphite) /, 2. /J is applied.

FIG. 3 shows another embodiment in which the walls of the processing chamber and the substrate holder itself are constructed of a material similar to the covering member in FIG. 2, as indicated by ioa and ita.

The ip diagram shows a modification of FIG. 2. In this case, instead of applying a graphite covering member 7.2 to the surface soil of the inner wall of the processing chamber r, a similar external material is used to cut the ion beam portion toward the inner wall. A barrier plate 2a made of (for example graphite) is provided around the substrate. In this case, it is also possible to use a substrate holder of the structure according to FIG. 2 or 3, which is shaped and/or dimensioned so that the ion beam does not hit the inner wall.

When graphite is used as in the illustrated embodiment, even if cardin re-deposit, it can be removed by heat treatment, so there is no problem.
Further, even when using a reactive gas ion beam, there is no problem of redeposition because the products on graphite are volatile. Furthermore, when graphite is used, charge-up does not occur because it is conductive.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a conventional ion beam etching apparatus, and FIGS. 2 to 2 are views similar to FIG. 1 showing different embodiments of the present invention. In the figure, r...-ion source, io...-processing chamber, ti...
・Put the board on /, 2. /J, /Hiro, 1B, //, 1-
y. A small member of Nogtutaring Yield.

Claims (1)

[Scope of Claims] t. An ion beam etching apparatus in which an ion beam generated in an ion source is supplied to an etching processing chamber, and the ion beam collides with the surface of a sample to perform etching processing by snogging. An ion device characterized in that a covering member with a small snogging yield or a member that does not contain heavy metals that have a serious effect on the sample to be etched is provided on at least the portion directly irradiated with the ion beam, such as the inner wall or the substrate holder. Beam etching equipment. 2. The device according to claim 1, wherein the cover member is formed as a surface coating layer of a portion directly irradiated with the ion beam. 3. The apparatus according to claim 1, wherein the cover member is formed around the processing substrate as a shielding plate for cutting off the ion beam directed toward the inner wall of the processing chamber.