JPS5975630A - Dry etching device - Google Patents

Abstract

PURPOSE:To increase an etching rate, and to maintain the uniformity of the distribution of the etching rate by specifying the ratio of a distance between a lower electrode and an upper electrode to the diameter of the upper electrode. CONSTITUTION:An upper electrode 2 and a lower electrode 3 are placed in parallel in a vacuum chamber 1 at the distance (d), a gas introducing port is formed to the upper section of the upper electrode 2, and a large number of gas outflow ports are formed to the surface opposite to the lower electrode 3. Exhaust ports are formed to the vaccuum chamber 1, and a semiconductor substrate 5 to be etched is placed on the lower electrode 3. An etching gas 4 is introduced from the upper section of the upper electrode 2, advances toward the semiconductor substrate 5 from a lower surface, and is discharged from the exhaust ports 6. When a high-frequency power supply 7 is connected to the lower section of the lower electrode 3, the upper electrode 2 is kept at ground potential and high-frequency power is applied, plasma is generated in the vacuum chamber 1, and the semiconductor substrate 5 is etched. When the diameter of the upper electrode 2 is made to be (g) and the distance between the upper electrode 2 and the lower electrode 3 (d) in such constitution, the uniformity of the etching rate is improved largely by bringing the ratio of g/d to 3.4 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a parallel plate electrode single wafer type dry etching apparatus.

Conventionally, dry etching equipment has been used in the manufacture of semiconductor devices, particularly in forming notches in semiconductor substrates. In particular, reactive ion etching using a parallel plate electrode single-wafer type dry etching apparatus is superior in that it has good reproducibility and can form a complete pattern.

FIG. 1 is a sectional view of an example of a parallel plate electrode single wafer type dry etching apparatus.

An upper electrode 2 and a lower electrode 141. The poles 3 are placed parallel to each other at a distance d. There is a gas inlet in the upper part of the upper electrode 2, and many gas outlet ports are provided in the upper electrode 2 facing the lower electrode 3.The vacuum chamber 1 is provided with an exhaust port 6. A semiconductor substrate 5 to be etched is placed on the pole 3. Etching gas 4I
'i upper' Hawk pole 2 is introduced from the upper part, upper 'RL pole 2
The gas advances from the bottom surface toward the semiconductor substrate 5 and is discharged from the exhaust port 6 . A high frequency power source 7 is connected to the lower part of the lower electrode 3,
When the upper electrode 2 is kept at ground potential and high frequency power is applied, plasma is generated in the vacuum chamber 1, and the semiconductor substrate 5 is etched.

In the above-mentioned dry etching apparatus, when an attempt is made to increase the etching rate, the uniformity of etching tends to deteriorate. In other words, the etching depth is 5
The disadvantage was that the degree of variation was large depending on the location. It is desirable that the etching rate distribution of the semiconductor substrate 5 is 15% or less, but this is difficult to achieve with conventional dry etching equipment, and in order to improve the uniformity, the etching rate must be lowered, resulting in an increase in work efficiency. There were drawbacks when efficiency decreased.

The present invention provides a dry etching apparatus which can eliminate the above-mentioned drawbacks, increase the etching rate, and maintain the uniformity of the etching rate distribution.

The dry etching apparatus of the present invention includes a parallel plate electrode sheet 1 which includes a flat lower electrode on which a substrate to be etched is placed, and a flat upper electrode facing the lower electrode in row f.
° In the lyetching device, the lower electrode and the upper
The ratio of 1 ton distance d from the polarization to the diameter g of the upper electrode is 3.
It is characterized by being 4 or less.

Embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, upper v1. When the diameter of the pole 2 is g and the distance between the upper electrode 2 and the lower electrode 3 is d, the ratio of g/d is set to 3.4 or less in the present invention. This greatly improves the uniformity of the etching rate.

Figure 2 shows the relationship between g/d and the A7 etching depth and etching rate distribution within the semiconductor substrate when an Al film provided on a semiconductor substrate is etched using the dry etching apparatus shown in Figure 1. It is a relationship diagram.

The solid line 11 indicates the etching depth of A/, and the broken line 12 Fi
This shows the etching rate distribution within a semiconductor substrate.

In this etching, the etching speed is 2000A
/min or more. As g/d decreases toward 3.4, as shown by the solid line 11, even if the Al etching depth becomes deeper, the variation in the etching rate distribution within the semiconductor substrate becomes smaller and smaller, as shown by the broken line 12. Na'
) When s g / d becomes 3.4 or less, it becomes 5 chi or less. If we increase the ratio of the distribution to 11, what used to be more than 10 chi becomes less than 5, which means that an improvement of more than 5 degrees has been achieved. This is considered to be because the plasma density I-effect becomes uniform by increasing N and the inter-electrode distance d relative to the upper electrode diameter g.

As described in detail above, according to the present invention, even if the etching rate is increased, a dry etching apparatus having a uniform etching rate distribution can be obtained, so the effect is significant.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of a parallel plate electrode single-capture type dry etching device, and FIG. 2 is a cross-sectional view of an example of the dry etching device shown in FIG.
FIG. 3 is a correlation diagram showing the etching depth of Al and the etching rate distribution in the semiconductor substrate with respect to g/d when an Al film provided on the semiconductor substrate is etched using a mounting method. 1...Vacuum chamber, 2...Upper electrode, Meter...Lower electrode, 4...Etching gas, 5...Semiconductor substrate, 6 ...Exhaust port, 11...Al etching depth, 12...
...Etching rate distribution within a semiconductor substrate. Ivy 1 diagram (97al l'$Z diagram

Claims (1)

[Claims] In a parallel plate electrode single-wafer type dry etching apparatus that includes a flat lower electrode on which a substrate to be etched is placed and a flat upper electrode facing parallel to the lower electrode,
A dry etching apparatus characterized in that the ratio of the distance pressure between the lower electrode and the upper electrode to the diameter g of the upper electrode is 3.4 or less.