JPH1032187A - Dry etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of clogging in jet holes, due to mixing of a foreign substance by a method, wherein a cooling gas line is provided with a gas line for flushing use for preventing the generation of the clogging of the jet holes. SOLUTION: A water 10 put on a lower electrode 1B is cooled with He gas introduced in dry etching device through gas jet holes 3 and an He gas line 2 during an etching or the wafer. When the etching of the wafer 10 ends, a first value 4A is turned off, and a variable valve 5 is fully opened. The line 2 is evacuated, and when the He has is exhausted for a set time, a second valve 4B is turned off. Since the dry etching device is in an idling state in this state, the He gas line 2 becomes an opened state. At this time, a valve 7 of a gas line 9 for flushing use is turned on, and a certain constant flow rate of N2 gas is introduced in the line 9 to perform a flushing in the line 2 and the gas jet holes 3. Thereby, even if peeling of a deposited substance produced by the etching is generated, the deposited substance introducing into the line 2 and the jet holes 3 is eliminated and clogging of the gas jet holes is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a dry etching apparatus, and more particularly to a structure of a cooling line on a back surface of a semiconductor substrate (wafer).

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional parallel plate type dry etching apparatus holds a wafer 10 by a clamp or the like on a lower electrode 1B having a gas ejection port 3.
The structure is such that He flows from the He gas line 2 connected to the jet port 3 to cool the wafer 10 during the etching process. In FIG. 2, 1A is an upper electrode, 4A and 4B.
Is a valve, 5 is a variable valve, 6 is a pressure gauge, and 11 is a water cooling plate.

[0003] When the etching is completed and the apparatus is in the idling state, the ejection port 3 on the back surface of the wafer 10 and the He gas line 2 connected to the ejection port are opened. In the etching chamber, a large amount of deposits generated by the etching process adhere. Therefore, when the deposits are peeled off or the like, there is a possibility that the deposits may enter the He gas line 2 from the ejection port 3 which is in the open state. In cleaning the chamber, the chamber is opened to the atmosphere. At this time, foreign matter may enter the chamber.

[0004]

The first problem is that foreign matter enters the jet port and the He gas line and causes clogging. When clogging occurs, the cooling capacity decreases, the temperature of the wafer surface increases, and resist burning occurs. As a result, the etching becomes non-uniform, and the reliability and yield of the semiconductor device decrease.

[0005] The reason is that there is no method for judging foreign matter even if it enters the jet port and the He gas line.

It is an object of the present invention to provide a dry etching apparatus which does not cause clogging of a jet port and a He gas line.

[0007]

According to the present invention, there is provided a dry etching apparatus comprising: an electrode for holding a semiconductor substrate; and a plurality of gas outlets for discharging an inert gas provided on the electrode to cool a back surface of the substrate. Wherein a gas line for flushing is provided in a gas line connected to the jet port in order to prevent clogging of the jet port.

[0008]

[Function] Since the jet port and the He gas line are flushed with N ₂ gas, even if the deposits generated by the etching are peeled off, no foreign matter enters the jet port and the He gas line, and the jet port and the He gas line are clogged. Is prevented beforehand. Therefore, resist burn product trouble due to clogging can be reduced.

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a dry etching apparatus for explaining an embodiment of the present invention.

Referring to FIG. 1, a dry etching apparatus includes a lower electrode 1B provided in a chamber and having a gas outlet 3 formed therein, an upper electrode 1A provided opposite to the lower electrode 1B, and a gas Connected to the outlet 3, the first valve 4A, the second valve 4B, the variable valve 5, and the pressure gauge 6
And a flushing gas line 9 connected to the He gas line 2 and having a valve 7 and a flow rate controller 8. In FIG. 1, reference numeral 11 denotes a water cooling plate for cooling the lower electrode 1B. The operation will be described below.

The wafer 10 placed on the lower electrode 1B
Indicates that the gas outlet 3 and the He gas line 2
It is cooled by the introduced He gas. The operation of the valves at the time of introducing the He gas is such that the wafer 10 is transferred onto the lower electrode 1B, the first and second valves 4A and 4B are opened, and the variable valve 5 is adjusted to the set pressure. The actual pressure is monitored by a pressure gauge 6. Wafer 10
Is completed, the first valve 4A is closed,
The variable valve 5 is fully opened. When the He gas line 2 is evacuated and evacuated for a set time, the second valve 4B is closed. In this state, the apparatus is in an idling state, and the He gas line 2 is in an open state.

At this time, the valve 7 of the flushing gas line 9 is opened, and a certain flow rate of an inert gas, for example, an inexpensive and easy-to-use N ₂ gas is introduced into the He gas line 2.
And flushing in the gas outlet 3. The flow control is performed by the flow controller 8. The flow rate of N ₂ gas is H
Make it smaller than e gas. For example, when He gas is used at 5 SCCM, N ₂ gas is used at ₂ to 3 SCCM. Even if the deposits generated by the etching process are peeled off by performing the flushing with the N ₂ gas, the deposits do not enter the He gas line 2 or the gas jet port 3, so that the resist burning does not occur.

[0013]

As described above, according to the present invention, clogging due to entry of foreign matter can be prevented by providing a gas line for flushing for preventing clogging of a jet port in a gas line for cooling. Therefore, resist burning can be prevented, and etching characteristics with good reproducibility can be obtained, so that the reliability and yield of the semiconductor device can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a dry etching apparatus for describing an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional dry etching apparatus.

[Explanation of symbols]

 Reference Signs List 1A Upper electrode 1B Lower electrode 2 He gas line 3 Gas outlet 4A, 4B Valve 5 Variable valve 6 Pressure gauge 7 Valve 8 Flow controller 9 Flushing gas line 10 Wafer

Claims (1)

[Claims] 1. A dry etching apparatus comprising: an electrode for holding a semiconductor substrate; and a plurality of gas outlets for ejecting an inert gas provided on the electrode to cool a back surface of the substrate. A dry etching apparatus, wherein a gas line for flushing is provided in a gas line connected to the jet port to prevent clogging.