JPH11176813A - Dry etching equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent attachment of a reactive product to a wafer introducing section and a gate valve in a chamber, in dry etching equipment. SOLUTION: A wafer stage 4 is provided with a shutter 13, which moves synchronously with the vertical movement of the wafer stage 4. While the wafer is etched, the shutter 13 is raised and shuts a wafer introducing section 11 and prevents the flow-in of reactive gas into the wafer introducing section 11 and thereby eliminates gas stagnation in the wafer introducing section 11. While the wafer is being carried in, the shutter 13 is lowered below the carried-in position together with the wafer stage 4 and thereby does not hinder the wafer carrying operation and enables suppression of the attachment of a reactive product to the wafer introducing section 11 and a gate valve 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching apparatus used for forming a thin film on a wafer using plasma.

[0002]

2. Description of the Related Art A conventional dry etching apparatus will be described with reference to the drawings. 2A and 2B are diagrams showing a schematic configuration of a conventional dry etching apparatus. FIG. 2A is a cross-sectional view showing a state during wafer transfer, and FIG. 2B is a cross-sectional view showing a state during wafer etching.

As shown in FIG. 2A, when etching a wafer 6 by a dry etching apparatus,
First, the gate valve 10 provided in the wafer introduction section 11 of the chamber 2 is opened, and the wafer 6 is carried into the chamber 2 by the transfer arm 7 and placed on the wafer stage 4. This gate valve 10 is provided outside the chamber 2. At this time, the wafer stage 4 is at a position lower than the wafer introduction unit 11. When the lift pins 3 protrude from the wafer stage 4 and the loaded wafer 6 is received, the transfer arm 7 returns to a fixed position outside the chamber 2 and the gate valve 10 is turned on as shown in FIG. Close.

When the transfer of the wafer 6 into the chamber 2 is completed, a high frequency is applied from the RF power source 5 to the wafer stage 4 (lower electrode), so that the space between the upper electrode 1 and the wafer stage 4 is reduced. Plasma discharge area 1
Plasma is generated in 2 and etching is started. The gas after the reaction is exhausted from the exhaust port 9. In the conventional apparatus, the shield plate 14 is arranged on the inner surface of the chamber 2 so as to cover the inside of the chamber 2 for protecting the side wall of the chamber. However, a portion corresponding to the wafer introduction unit 11 does not hinder wafer transfer. It is open as follows.

[0005]

The above-mentioned conventional dry etching apparatus has the following problems. The first problem is that the reaction product selectively adheres to the wafer introduction part 11 and the gate valve 10 of the chamber 2. The reason is that when the etching is started in the chamber 2 as shown in FIG. 2B, the temperature of the plasma discharge region 12 increases due to the heat of the plasma. However, the temperatures of the wafer introduction part 11 and the gate valve 10 do not rise so much, and a temperature difference occurs between the temperature and the plasma discharge region 12.
Further, since the wafer introduction part 11 is depressed with respect to the inner wall of the chamber 2, the flow of the reaction gas in this part stagnates. This is because the reaction product selectively adheres to the wafer introduction part 11 and the gate valve 10 due to the gas stagnation and the temperature difference.

A second problem is that the production yield of wafers is reduced. The reason is that the reaction products attached to the wafer introduction part 11 and the gate valve 10 are peeled off and become particles, which adhere to the wafer being transported, and cause pattern defects.

An object of the present invention is to improve the quality and yield of devices by preventing reaction products from adhering to a wafer introduction portion and a gate valve and reducing generation of particles.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a dry etching apparatus for loading a wafer from a wafer introduction portion provided in a chamber, placing the loaded wafer on a wafer stage, and performing etching by plasma discharge. A shutter for shutting off the wafer introduction section inside the chamber is provided, and the shutter is attached to the wafer stage, and operates the shutter in synchronization with the operation of the wafer stage;
At the same time that the wafer stage is raised, the shutter is also raised, and the raised shutter shuts off the wafer introduction unit, and when the wafer stage is lowered, the shutter is also lowered, opening the wafer introduction unit and loading and unloading the wafer.
Further, the dry etching apparatus is characterized in that the wafer introduction part is shut off by a shutter during etching, and the inflow of the reaction gas from the plasma discharge region to the wafer introduction part is suppressed.

[0009]

Next, an embodiment of a dry etching apparatus according to the present invention will be described with reference to FIG. FIG. 1A is a cross-sectional view showing a state where a wafer is being transferred.
FIG. 4B is a cross-sectional view showing a state during wafer etching.

In the dry etching apparatus of the present embodiment, as shown in FIG. 1A, an upper electrode 1, a chamber 2, a lift pin 3, a wafer stage 4, an RF power source 5,
The structures of the transfer arm 7, the gas inlet 8, the exhaust port 9, the gate valve 10, and the shield plate 14 are the same as those of the prior art. The difference in structure is that a shutter 13 is mounted on the wafer introduction section 11 side of the wafer stage 4.

Next, the operation of the embodiment of the dry etching apparatus of the present invention will be described. As shown in FIG. 1A, when performing an etching process on a wafer 6 using a dry etching apparatus, first, a gate valve 10 for opening and closing a wafer introduction unit 11 of a chamber 2 is opened, and the wafer 6 The wafer 7 is carried into the chamber 2 by the reference numeral 7 and placed on the wafer stage 4. This gate valve 10
Is provided outside the chamber 2. At this time, the wafer stage 4 is at a position lower than the wafer introduction unit 11. When the lift pins 3 protrude from the wafer stage 4 and the loaded wafer 6 is received, the transfer arm 7 returns to a fixed position outside the chamber 2 and the gate valve 10 is turned on as shown in FIG. Close.

When the loading of the wafer 6 into the chamber 2 is completed in this way, the wafer stage 4 (lower electrode) starts to rise, the shutter 13 also rises in synchronization with the wafer stage 4, and the wafer introduction section 11 From the inside of the chamber 2. Here, when a high frequency is applied to the wafer stage 4 from the RF power supply 5, a plasma is generated in the plasma discharge region 12 between the upper electrode 1 and the wafer stage 4, and etching is started. The gas after the reaction is exhausted from the exhaust port 9. During the etching, the wafer introduction part 11 is shut off from the plasma discharge region 12 by the shutter 13. When the etching is completed, the wafer stage 4 is lowered, the shutter 13 is also lowered, the wafer introduction part 11 is opened, and the wafer 6 is unloaded from the chamber 2 by the transfer arm 7.

According to the present embodiment, by providing the shutter formed integrally with the wafer stage, the shutter closes the wafer introduction portion during the etching, and the shutter is moved together with the wafer stage during the wafer transfer. Since the wafer introduction section is opened by further descending, it is possible to prevent the flow of the reaction gas into the wafer introduction section without hindering the transfer of the wafer. As a result, stagnation of the reaction gas at the wafer introduction portion and the gate valve can be suppressed, so that the adhesion of the reaction product can be suppressed. The material and shape of the shutter are not particularly limited as long as they satisfy predetermined performance, but an alumite material of the same material as the shield plate is preferable. Further, it is needless to say that the shutter structure can be applied to a vacuum device other than the dry etching device.

[0014]

As described above, the first effect of the dry etching apparatus of the present invention is that the reaction products can be prevented from adhering to the wafer introduction portion and the gate valve. The reason is that shutting off the wafer introduction portion and the gate valve with a shutter can prevent gas from flowing into the wafer introduction portion, which is lower in temperature than the plasma discharge region. The second effect is that it can contribute to improving the quality and yield of semiconductor devices.
The reason is that the generation of dust from the wafer introduction portion and the gate valve eliminates the possibility of a pattern short-circuit on the wafer.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a dry etching apparatus according to the present invention, wherein FIG.
(B) is a sectional view during wafer etching.

FIG. 2 is a view showing a conventional dry etching apparatus;
2A is a cross-sectional view during wafer transfer, and FIG. 2B is a cross-sectional view during wafer etching.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper electrode 2 Chamber 3 Lift pin 4 Wafer stage 5 RF power supply 6 Wafer 7 Transfer arm 8 Gas inlet 9 Exhaust port 10 Gate valve 11 Wafer introduction part 12 Plasma discharge area 13 Shutter 14 Shield plate

Claims (5)

[Claims] 1. A dry etching apparatus in which a wafer is loaded from a wafer introduction section provided in a chamber, and the loaded wafer is placed on a wafer stage and etched by plasma discharge. A dry etching apparatus comprising a shutter for shutting off. 2. The dry etching apparatus according to claim 1, wherein the shutter is mounted on a wafer stage, and the operation of the shutter is synchronized with the operation of the wafer stage. 3. The dry etching apparatus according to claim 1, wherein the shutter is raised at the same time as the wafer stage is raised, and the wafer introduction part is blocked by the raised shutter. 4. The dry etching apparatus according to claim 1, wherein the lowering of the wafer stage and the lowering of the shutter at the same time as the lowering of the wafer stage open the wafer introduction portion to carry in and carry out the wafer. 5. The dry etching apparatus according to claim 1, wherein a wafer introduction portion is shut off by a shutter during etching to prevent a reaction gas from flowing from the plasma discharge region to the wafer introduction portion.