JPS59208725A - Reaction apparatus - Google Patents

Abstract

PURPOSE:To uniformize reaction rate for all processing objects and uniformize reaction processings by varying area ratio of parallel falt electrodes. CONSTITUTION:A couple of parallel flat electrodes 2, 3 are provided in an etching chamber 1. A high frequency oscillation power supply 6 is connected to the upper side anode electrode 2 and the lower cathode electrode 3 is connected to the earth. The etching chamber 1 is provided with the etching gas inlet port 4 and the exhaust port 6. Moreover the cathode electrode 3 is formed so that a plurality of processing object, the wafers 7 can be placed thereon and the upper surface area can be changed by the removable rings 3b, 3c. The reaction rate of all processing objects can be uniformized and the reaction processing can also be uniformized by varying an area ratio of both electrodes 2, 3 in accordance with the reaction processing conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a reaction technology, and in particular to a technology that utilizes a gas-electric reaction caused by parallel plate electrodes, and relates to a technology that is effective for use in, for example, dry etching processing.

[Background technology]

In the manufacturing process of semiconductor devices, it is conceivable to form fine patterns on a wafer using a dry etching device equipped with parallel plate electrodes.

However, in this case, depending on the type of etching gas, atmospheric pressure, etc., the etching rate becomes faster in the center of the wafer and slower in the periphery, resulting in a phenomenon in which the etching process becomes uneven over the entire wafer. The inventor has made it clear that this is the case.

[Purpose of the invention]

An object of the present invention is to provide a reaction apparatus that can uniformize reaction treatment over the entire object to be treated.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, by changing and adjusting the area ratio of the parallel plate electrodes according to the reaction treatment situation, the reaction rate in the entire object to be treated is equalized and the reaction treatment is made uniform.

〔Example〕

FIGS. 1 and 2 are longitudinal sectional views before and after electrode adjustment, showing an example of applying the reaction device according to the present invention to a dry etching device, and FIGS. 3 and 4 show the effects before and after adjustment. Each diagram is a diagram.

In this embodiment, this etching apparatus is equipped with an etching chamber 1 as a reaction chamber, and this etching chamber 1 is provided with a pair of parallel plate electrodes 2 and 3. The etching chamber 1 is formed with an etching gas inlet 4 and an exhaust port 5 for exhausting the interior of the chamber. A high frequency oscillation power source 6 is connected to the upper anode electrode 2, and the lower cathode electrode 3 is connected to ground.

The cathode electrode 3 is configured to be able to hold a plurality of wafers 7, which are objects to be processed, in a mounted state. This electrode 3 has a plurality of rings 3b, 3c, .

By being triple fitted, the area of the upper surface can be changed. The main body 3a and each of the rings 3b, 3c are connected to each other by engaging a convex portion 8 and a concave portion 9, which are formed in annular shapes on the outer and inner circumferences of the body 3a and the rings 3b and 3c, respectively. It is configured so that

Next, I will explain how it works.

For example, as shown in FIG. 1, with the area ratio of the anode electrode 2 and cathode electrode 3 set to 1:1, a chlorine-based gas (CCi4, etc.) is introduced into the etching chamber 1 as an etching gas from the inlet 4. However, when etching is performed on the wafer 7 on the cathode electrode 3 by applying a high frequency voltage to both electrodes 2 and 3, as shown in FIG. It will be late.

As a result, the etching depth on the wafer becomes uneven, deep in the center and shallow in the periphery.

Therefore, as shown in FIG. 2, the area of the cathode electrode 3 is made larger than the area of the anode electrode 2 by fitting the second auxiliary ring 3c to the outer periphery of the first auxiliary ring 3b of the cathode electrode 3. The area ratio of both electrodes 2 and 3 is set to a predetermined value (a value determined in advance through experiments, etc.).

In this case, as shown in FIG. 4, the etching rate becomes approximately uniform over the entire wafer, and the etching depth becomes uniform. In addition, in this case, an undercut (y) with an inverse shape to the resist pattern (so-called negative slope)
Anisotropic etching can be obtained without

Furthermore, the etching speed ratio (selectivity) for the sea urchin base and resist is sufficiently high. This is thought to be because the plasma atmosphere has spread and the influence of plasma etching on the wafer has been alleviated as the diameter of the cathode electrode has increased.

By the way, as shown in FIG. 1, when the area ratio of both electrodes 2 and 3 is 1:1 and a fluorine-based gas (such as cF'4) is used as the etching chamber, the etching rate is equal to that of the entire wafer. approximately equal across the range. This is considered to be because in the etching situation using fluorine gas, reactive ion etching acts more and plasma etching has less influence. Therefore, when a fluorine-based gas is used, it is desirable that the area ratio between the electrodes 2 and 3 be 1:1.

Furthermore, under the same etching gas usage conditions, if the pressure in the etching chamber 1 is increased (and the etching rate becomes uneven as shown in Fig. 3), as shown in Fig. 2, the cathode electrode When the etching area is made larger than that of the anode electrode 2, the etching rate becomes uniform over the entire area. Etching occurs in a low pressure region (10 to 10 Torr), but by increasing the area of the cathode electrode 30, the range of plasma etching expands to the outside of the wafer placement surface, and the influence of plasma etching on the wafer is alleviated. This is thought to be due to the fact that plasma etching has a faster etching speed.

〔effect〕

(1) By making the area ratio of parallel plate electrodes variable,
Since it is possible to create a reaction treatment situation at an equal rate over the entire object to be treated, the reaction treatment is uniformly performed over the entire object.

(2) By appropriately adjusting the area ratio of the parallel plate electrodes in the dry etching device, the type of gas, the pressure, etc. according to the etching situation, the etching rate can be made uniform over the entire object, and a large selection ratio can be achieved. Also, it is possible to obtain etching processing with good dimensional accuracy and no negative slope.

(3) By making the area of the electrode variable by attaching and detaching the ring, the area ratio of both electrodes can be changed by a simple operation.

Although the invention has been specifically explained above based on the embodiments of the invention made by the present inventor, it goes without saying that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways without departing from the gist thereof. Nor.

For example, the area ratio of both electrodes can be changed not only by increasing or decreasing the area of the cathode electrode, but also by changing the area of the anode electrode or both electrodes.

The area variable structure of the electrode is not limited to the ring attachment/detachment structure, and the area variable adjustment operation is not limited to manual operation but may be performed automatically.

[Application field]

In the above explanation, the invention made by the present inventor was mainly explained in the case where it was applied to a dry etching apparatus, which is the background field of application, but the invention is not limited to this, and for example, a CVD apparatus. It can also be applied to

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view after increasing the electrode area, and FIGS. 3 and 4 are diagrams showing the distribution of etching rates. 1- Etching chamber (reaction chamber), 2... Anode electrode, 3... Cathode electrode, 3b, 3c... Ring, C
... Gas inlet, 5... Exhaust port, 6... High frequency oscillation power supply, 7... Wafer (processing target). Agent Patent Attorney Akio Takahashi To 'N Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] ], in a reaction apparatus equipped with a pair of parallel plate electrodes,
A reaction device characterized in that the area ratio of the two electrodes is variable. 2. The reaction device according to claim 1, characterized in that a ring is removably fitted to at least one of the electrodes.