JPS59173275A - Plasma etching device - Google Patents

Abstract

PURPOSE:To perform etching with the reduced amount of residua, in the parallel-plate titled device, by specifying the area ratio of a workpiece to be etched to an electrode to be exposed to plasma and esp. a distance from the end of the workpiece to be etched to the end of a plate electrode. CONSTITUTION:In case of the parallel-plate plasma etching batch treatment device, the diamter of spot facing for fixing a workpiece to be etched is trated as X, and distances from the central and end parts of a plate electrode 1 to the end of the spot facing are treated as Z and Y, respectively. A wafer 3 to be etched and a quartz electrode cover 2 are provided at the spot facing and the electrode 1, respectively. Hereon, formula I is satisfied. In case of a plasma etching device for treating a single plate, formula II is satisfied, wherein V and W are the diameter of the wafer 3 on the electrode 1 and the shortest distance from the end of the wafer 3 to the end of the electrode 1, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a parallel plate type plasma etching apparatus.

■The manufacturing of C1 is becoming more and more microfabricated year by year.

An indispensable technique for microfabrication is anisotropic etching, that is, a technique that allows etching to be performed in accordance with a photoresist pattern without undercutting. The equipment used for this etching is a plasma etching equipment. Plasma etching requires no undercuts, no etching residue or polymer deposits.

The present invention relates to a plasma etching apparatus that enables etching without leaving any etching residues.

In recent years, various types of anisotropic etching have been performed using a parallel plate type plasma etching apparatus. In the above-mentioned plasma etching method, it is required that etching can be formed through the resist pattern, that is, there should be no undercuts and no residues.

As for the residue, as a result of conventional studies, we found that the gas used in plasma etching, plasma power, pressure,...
It has been confirmed that etching conditions are an important factor. On the other hand, the material of the parallel plate electrodes has also been found to be a major factor. For example, when etching a silicon oxide film, it is better to use an Al electrode than a quartz cover electrode, since less polymer adhesion is left behind, and when etching polysilicon, it is better to use a carbon electrode than a stainless steel electrode. There is less residue left behind...etc. However, up to now, even if etching is carried out with the above-mentioned considerations in mind, the residue cannot be completely removed.

In order to prevent residue during plasma etching, the present invention has newly improved the ratio of the area of the object to be etched to the area of the electrode exposed to plasma, especially the distance from the edge of the object to be etched, and the distance at the edge of the electrode plate to a certain extent. It is 15 things to do less shallow etching at a distance of more than 1/2 inch.

The present invention will be explained using examples.

FIG. 1 shows the case of a parallel plate type plasma etch patch processing type apparatus. X is the diameter of the counterbore for fixing the object to be etched, and Z and Y are the distances from the center of the flat plate electrode and the end of the flat plate electrode to the end of the counterbore for fixing the object to be etched, respectively.

FIG. 2 is a sectional view taken along the line AA' in FIG. 1, in which a wafer 3 to be etched is placed in the counterbore, and a quartz electrode cover 2 is provided on the flat electrode 1.

In this example, quartz is used for the electrode cover 2, and Z/
When X≧1.0 and Y/X≧0.5, good anisotropic plasma etching conditions with no residue were obtained. In normal cases,
In many cases, Z/X=0.5 to 1.3 and Y/X=0.1 to 0.3, but in this case, residue is likely to be left.

FIGS. 3 and 4 show an embodiment of a parallel plate plasma etching apparatus of a single-sheet processing type. In this case, if the relationship between ■ corresponding to the wafer 3 to be etched on the flat electrode 1 and the distance W to the edge is W/V≧0.3, favorable anisotropic etching conditions with no residue can be achieved. was gotten. Of course, if the etching conditions are isotropic, the above Z/X, , Y/X, W/V
(Even if the D value 't'&t. If the relationship between the electrode surfaces is set to a value greater than or equal to the above-mentioned value, a plasma etching apparatus can obtain good anisotropic etching conditions with less residue.

[Brief explanation of the drawing]

Fig. 1 is a top view of the lower electrode of a parallel plate type plasma etching apparatus according to an embodiment of the present invention, which is a batch processing type, Fig. 2 is a part of the AA' cross-sectional view of Fig. 1, and Fig. 3 is a single-sheet processing type parallel A top view of the lower electrode of the embodiment of the present invention in a flat plate type plasma etching apparatus, FIG. 4 is a part of the sectional view taken along line AA' in FIG. 1... Flat & electrode, 2... Quartz electrode cover, 3... Wafer to be etched. GaoA4fOh1= INIヮ -・、勺＼jl-
! Figure 3

Claims (1)

[Claims] In a parallel plate type plasma apparatus, in a batch type plasma etching apparatus, X is the diameter of the counterbore that holds the object to be etched, Y is the shortest distance from the end of the core bore to the electrode end, and X is the diameter of the counterbore that holds the object to be etched. When the shortest distance from the edge of the electrode to the center of the electrode is Z, the relationship Z/X≧1, O is satisfied. A plasma etching apparatus characterized by satisfying the relationship W/V≧03, where W is the shortest distance from the edge of the etching object to the edge of the electrode. −−1−) 1−°−゛°゛−′−