JPH0529272A - Plasma etching device - Google Patents

Abstract

PURPOSE:To provide a plasma etching device which can restrain undesirable particles from flying and attaching to an etching object. CONSTITUTION:In a plasma etching device where etching gas introduced into a vacuum chamber 1 is turned into plasma by applying a voltage to it to carry out the dry etching of an etching object 10 in the vacuum chamber 1, a cover 7 and a cover drive device 8 are provided to cover the etching object just before or after a prescribed etching operation is finished while the vacuum chamber 1 is not substantially changed in degree of vacuum are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching apparatus for dry etching an etching object in a chamber by applying a voltage to the etching gas introduced into the vacuum chamber to generate plasma. Regarding

[0002]

2. Description of the Related Art A plasma etching apparatus of this type includes
Broadly speaking, there are an RIE mode (reactive ion etching mode) device and a plasma mode device.
As shown schematically in FIG. 2, the former arranges upper and lower electrodes 2 and 3 in a vacuum chamber 1 which can be evacuated to a predetermined pressure by a vacuum pump 4, and the upper electrode 2 is a ground electrode and the lower electrode 3 is a ground electrode. The high frequency electrode is used and the etching target 10 is placed on the electrode 3.

According to this apparatus, the etching gas introduced into the vacuum chamber 1 maintained at a predetermined degree of vacuum is turned into plasma under the application of a high frequency voltage, and the etching object 10 is exposed to this plasma. It will be etched. On the other hand, the latter plasma mode device is shown in FIG.
The upper electrode 2 of the upper and lower electrodes 2 and 3 in the vacuum chamber 1 is the high frequency electrode, the lower electrode 3 is the ground electrode, and the etching target 10 is placed on the electrode 3 as shown in FIG. is there.

Also in this case, as in the RIE mode apparatus, the etching object 10 is etched by being exposed to the plasma of the etching gas. In any of the above devices, when the predetermined etching is completed, the high-frequency voltage application, the introduction of the etching gas is stopped, the gas in the chamber 1 is exhausted, and instead, the N ₂ gas is introduced to perform the venting treatment, After that, the etching target 10 is taken out or moved to the next process chamber together with the high frequency electrode while maintaining the vacuum in the chamber 1.

[0005]

However, when the etching is completed and the high frequency voltage application and the etching gas introduction are stopped and the gas is exhausted, the molecules that are etched and suspended in the chamber 1 are During the exhaust operation, there is a problem that the particles drop onto the etching target 10 to become particles and adhere, and the particles adhered to the inner wall of the chamber 1 drop onto the etching target 10 and adhere.

The adhesion of such particles is caused by etching a thin film for a device formed on a substrate such as glass according to a predetermined pattern in the process of manufacturing a large area liquid crystal display device, an amorphous silicon solar cell, or the like. In this case, there are problems that the particles are mixed in at several places in the finally obtained large-area device, so that the entire expensive device must be discarded.

[0007] Therefore, an object of the present invention is to provide a plasma etching apparatus capable of suppressing inconvenient particles from flying and adhering to an object to be etched.

[0008]

According to the above object, the present invention provides an etching gas introduced into a vacuum chamber,
In a plasma etching apparatus for dry-etching an etching target in the chamber by applying a voltage to the chamber to generate plasma, while the vacuum degree in the chamber does not substantially change immediately before or after the predetermined etching is completed. In addition, the present invention provides a plasma etching apparatus comprising a cover for covering the etching target and a driving means for the cover.

When the object to be etched is covered with the cover, helium (H
An inert gas such as e) or argon (Ar) may be introduced into the cover to more reliably suppress scattering and adhesion of particles.

[0010]

According to the plasma etching apparatus of the present invention, immediately before or immediately after the end of etching of the object to be etched,
The object to be etched is covered with the cover while the degree of vacuum in the vacuum chamber does not change or remains almost unchanged during the etching process, that is, while the degree of vacuum remains substantially unchanged.
As a result, inconvenient particles are prevented from scattering and adhering to the object.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall schematic sectional view of one embodiment. This plasma etching apparatus is an improvement of the conventional apparatus in the RIE mode shown in FIG.

This etching apparatus comprises a vacuum chamber 1,
Upper and lower electrodes 2, 3 installed in chamber 1, chamber 1
To the vacuum pump 4, which is connected to the chamber 1 via a solenoid valve 41, a vent gas introducing solenoid valve 40 which is connected to the chamber 1, an N ₂ gas source 400 which is connected to the valve, and a gas introducing port 11 of the chamber 1.
Is connected to the etching gas source 5. Electrode 2
Is a ground electrode, the electrode 3 is a high frequency electrode, and is connected to a high frequency power supply 31.

This etching apparatus further includes a cover storage chamber 6 connected to the chamber 1 and a cover 7 stored in the chamber.
And a drive device 8 for the cover 7. The storage chamber 6 is also connected to the pump 4 via the solenoid valve 42. A gate valve 9 is provided between the cover storage chamber 6 and the chamber 1. The gate valve can be opened / closed so that the storage chamber 6 and the chamber 1 are airtightly separated or the cover 7 can reciprocate.

The cover 7 is supported by an arm 71, which can reciprocate in the horizontal direction A in an airtight manner by a sealing device 62 such as a magnet feedthrough provided on a wall 61 of the cover storage chamber 6. And is connected to the drive device 8 outside the storage chamber 6. Drive device 8
Is an arm 7 driven by a motor via a rack and pinion mechanism.
1 and therefore the cover 7 can be reciprocally driven. By driving this device, the cover 7 advances to the position P1 retracted into the storage chamber 6 or into the chamber 1 to move the etching target 10 on the electrode 3 upward. It is possible to take a position P2 where it can be covered. The drive device 8 is not limited to the one described above,
A piston cylinder device or other means may be used.

The cover 7 is a plate-like member having an area sufficient to cover the object 10 to be etched, and its peripheral portion is bent downward. In this example, argon gas (Ar) can be introduced into the cover 7 from an inert gas source 72. According to the plasma etching apparatus described above, the etching object 10 is first set on the electrode 3 in the vacuum chamber 1. Next, the inside of the vacuum chamber 1 is brought to a predetermined vacuum degree by opening the electromagnetic valve 41 and operating the vacuum pump 4, and the etching gas is introduced from the etching gas source 5 into the vacuum chamber 1. Then, a high-frequency voltage is applied by the high-frequency power source 31 to turn the etching gas into plasma. Thus, the etching object 10 is etched.

On the other hand, prior to the end of the etching, the inside of the cover housing chamber 6 is evacuated to the same degree as the degree of vacuum during the etching process in the vacuum chamber 1 by opening the solenoid valve 42 and operating the pump 4. .. Immediately before the end of etching, the gate valve 9 is opened, and the argon gas is supplied from the inert gas source 72 to the bottom of the cover 7, the cover 7 is advanced into the chamber 1 by the operation of the driving device 8, and the position is set. The etching target 10 is covered with P1.

After the cover 7 covers the object 10 to be etched, the chamber 1 is evacuated by opening the valve 41 and operating the pump 4, and when the exhaust is completed, the electromagnetic valve 40 for introducing the vent gas is opened, and the chamber 1 is opened. N ₂ gas is introduced into the chamber 1 for venting. As soon as the exhaust is finished,
The cover 7 is retracted to the position P2, and the gate valve 7
2 is closed and the supply of argon gas is also stopped.

In this way, the etching object 10 after the desired etching can be taken out from the chamber 1. In addition, in a state where the etching object 10 is covered with the cover 7,
Alternatively, the object 10 may be moved back to the storage chamber 6 and moved to the next process chamber (not shown). According to the above apparatus, when the gas is discharged from the vacuum chamber 1 after the etching is completed, the etching object 10 is covered with the cover 7, and since the cover 7 is supplied with the argon gas, Inconvenient particles are prevented from flying and adhering to the etching object 10.

When the above apparatus was operated under the following conditions (however, Ar gas was not introduced under the cover), it was confirmed that particle adhesion was significantly suppressed. Size of electrodes 2 and 3: Square with a side of 200 mm High frequency power source 31: 500 W, 13.56 MHz Vacuum degree of chamber 1: 0.3 Torr during etching, 0.003 Torr during gas exhaust Etching gas: CF ₄ / O ₂ (9: 1) 100
ccm Etching object 10: 1 μm amorphous silicon (a-Si) film formed on a Si wafer having a diameter of 6 inches Etching rate: 1500 Å / min Chamber 1 temperature: 70 ° C. Final condition The number of particles having a particle size of 5 μm or more on the etching object 10 obtained in Step 1 is 20 to 50.
It was an individual. The number of particles on the same type of etching target by the conventional apparatus in the RIE mode is 100 to 100.
It was 300. From this, it is understood that the apparatus according to the present invention is effective in suppressing particles from flying and adhering to an etching target, especially a large-area substrate.

[0020]

As described above, according to the plasma etching apparatus of the present invention, it is possible to suppress inconvenient particles from flying and adhering to the object to be etched.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional example.

FIG. 3 is a schematic sectional view of another conventional example.

[Explanation of symbols]

1 Vacuum Chamber 11 Gas Inlet 2 Grounding Electrode 3 High Frequency Electrode 31 High Frequency Power Supply 4 Vacuum Pump 40, 41, 42 Solenoid Valve 400 N ₂ Gas Source 5 Etching Gas Source 6 Cover Storage Room 7 Cover 71 Cover Support Arm 72 Inert Gas Source 8 Drive 9 Gate valve

Claims (1)

Claim: What is claimed is: 1. A plasma etching apparatus for dry etching an etching target in a chamber by applying a voltage to the etching gas introduced into the vacuum chamber to generate plasma. In the plasma etching apparatus, a cover for covering the etching object and a driving means for the etching object are provided immediately before or immediately after a predetermined etching, while the degree of vacuum in the chamber does not substantially change.