KR940000914B1 - Pedestal for dry etching process of oxide film - Google Patents

Abstract

The pedestal for etching replaces an elastomer (5a) with a kapton tape (5b) which has high endurance and no deterioration in the plasma environment. The kapton tape (5b) is positioned between the surface of the pedestal includes: an upper clip (3) and a lower clip (4) of a pedestal ring (2) fixing the wafer; a set screw (6) and a wafer button (7) supporting the wafer.

Description

Pedestal for Oxide Dry Etching

1 is a block diagram of a pedestal (Pedestal) of the present invention.

2 is a cross-sectional view along the line AA ′ of FIG. 1.

3 shows a set screw and a wafer button according to the present invention, (a) is a perspective view, and (b) is a sectional view.

* Explanation of symbols for main parts of the drawings

1 ： Pedestal surface 2 ： Pedestal Ring

3: upper clip 4: lower clip

5a: Elastomer 5b: Kapton Tape

6: set screw 7: wafer button

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedestal for oxide dry etching, and in particular, a pedestal insulating layer which comes into contact with a wafer in a pedestal for etching a wafer is changed to a durable, non-degradable, and free of particles, thereby suppressing particle generation and uniformity. The present invention relates to a pedestal for an oxide film dry etching capable of managing a crystal size (CD).

In manufacturing semiconductor devices such as transistors (TR), integrated circuits (ICs), and large-scale integrated circuits (ISLs), diffusion, photoresist coating, etching, and deposition are performed on wafers made of semiconductor materials such as silicon (Si). When fine dust or other contaminants adhere to the surface of the wafer, scratches on the surface of the wafer, uneven thickness of the film, or poor wafer transfer may occur.

Contamination sources of wafers include air, production facilities, people, water, chemical gases, and static charges. Contamination by the contaminants causes abnormal oxide growth or stains on the wafer surface, formation of etched wafer surfaces, and metals. The ion causes a problem of lowering the reliability of the device formed on the wafer.

In general, the process chamber is supplied with RF power from the RF generator to form a plasma, and the plasma gas is ionized to become reactive while being used as a means for etching a wafer. In this process chamber, the pedestal on which the wafer is placed corresponds to the cathode electrode, and a reactive gas ionized with + generated in the plasma has electrical energy and impacts the wafer to etch. In this process, the wafer is charged to the electrical state of-and subjected to high temperature (about 110-120 ° C) heat in the plasma. At this time, the role of the insulating film in the contact surface between the pedestal and the wafer is very important, because it must be long-term at high temperature requires durability and particles should not be generated.

However, in the conventional pedestal for oxide dry etching, an elastomer 5a is placed inside the pedestal ring 2, that is, on the pedestal surface 1, so that a wafer is placed on the elastomer 5a and the clips 3 and 4 are placed on the pedestal ring. It was a pedestal that dry-etched the oxide film of the wafer on which the oxide film was formed after fixing it. However, since the elastomer 5a is a material that is severely worn by contact with a large amount of wafers, particles are generated in the insulating film, which reduces the yield. It lowers the operation rate of the material and also deteriorates the material while receiving high heat for a long time, so that the wear of the insulating film is accelerated and buried on the back of the wafer. Such contamination of the wafer surface causes poor wafer loading due to the poor adhesion state of the PR, and in particular, when the insulating film swells due to heat, the contact between the pedestal and the wafer becomes very poor and the etching state worsens. do. If the etching state is poor, the etching rate and amount in the wafer become inconsistent and the critical dimension (CD) measurement value of the wafer is out of tolerance, thereby treating the wafer as defective.

Of course, there is a cleaning system such as DI water system or sulfuric acid washing in the process of oxidizing the cleaned wafer, measuring the surface of the oxidized wafer under a microscope, and going through the PR process, but it is difficult to rinse the container. Therefore, it should be avoided as much as possible, and a thin oxide film (100-200Å) in the cleaning bath prevents the uniform and contamination-free oxide film from growing on the wafer surface.

In addition, such an oxide etching process requires high accuracy, and the wafer is completely deficient in a single mistake, so the wafer having a low yield or low yield must be immediately selected. To this end, various tests and evaluations are required when the wafer passes through various process steps, and contamination detection of the wafer is essential for high yield and contamination prevention.

Wafers that arrive at the laboratory are inspected from particle contamination. In the case of the conventional pedestal, the particle contamination of the wafer by the elastomeric material can be seen through naked eye or electron scanning microscope (SEM) by high intensity light.

As a result of the inspection, in the conventional pedestal using the elastomer 5a, the wafer 5a adheres to the back side of the wafer, causing contamination and scratches on the back side of the wafer, resulting in poor crystal size (CD), and the wafer loading after transfer in the pedestal. Wafer loading will cause defects.

SUMMARY OF THE INVENTION The present invention has been invented in view of the above-described circumstances, and a wafer generated by an elastomer (5a) material, which is an insulator of a pedestal, by providing an insulating film made of a Kapton tape material that is durable and does not deteriorate even in plasma, thereby preventing particle generation. Pedestal for oxide dry etching that can prevent facility contamination and additional pedestal contamination, solve process defects caused by the contamination, and improve the equipment operation rate and reduce cost by semi-permanently extending the life of uniform etching and pedestal. The purpose is to provide.

In order to achieve the above object, the present invention achieves uniform etching by constructing a pedestal using Kapton tape 5b having high insulation and heat resistance and low cost instead of elastomer 5a, which is a contaminant of the process, and under conventional thermal environment conditions. As in the pedestal, there is a characteristic that the oxide film can be etched.

The uniform etch depends on several parameters, including the thickness and density of the layer to be etched, the energy and temperature of the etchant, the tackiness of the photoresist (PR) and the etchant of the wafer surface. Uniformity, etc.

The photomasking process after the oxide film dry etching process described above is a process of transferring a pattern from a mask to a surface of a wafer using a PR layer, and the purpose of the photoresist application is to provide a suitable wafer surface. Since it is uniformly coated with thickness and PR, it can be seen that the adhesion of PR is good when the wafer is clean.

In addition, undercut and PR lift occurs when the wafer surface is contaminated. In order to improve the adhesiveness of PR in the general semiconductor manufacturing process line, the surface treatment process is adopted. It will be readily apparent to one of ordinary skill in the art that the need for dry, dry and chemically treated surfaces is required.

Looking at the flow of basic photomasking, the objective of solving the above-described wafer surface contamination problem becomes clear.

First, the surface preparation process for cleaning and drying the wafer surface.

Secondly, a PR forming process of coating a photoresist thin film on the wafer.

Third, a soft bake process to evaporate the PR solvent to improve adhesion.

Fourth, a development process of removing unmultiplexed PR is performed.

Diffusion, ion implantation, chemical vapor deposition, and metallization processes are performed after the photomasking step of the wafer described above. Of course, all of the above processes must be performed in a clean and dry environment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing the structure of the pedestal for oxide dry etching of the present invention, and FIG. 2 is a sectional view taken along the line A-A 'of the pedestal shown in FIG. 1, and insulates the side surface of the pedestal around the pedestal surface 1. An insulator is laid on the pedestal surface 1 which is the surface to which the pedestal ring 2 and the wafer are attached.

The insulator conventional elastomer (5a) serves to transfer the insulated and cooled temperature by contact between the pedestal surface (1) and the back of the wafer, the upper clip between the pedestal ring (2); 3) and the lower clip (4) serves to fix the wafer on the pedestal surface (1), the set screw (6) and the wafer button (wafer) in a predetermined area of the pedestal ring (2) button 7) supports the wafer not to fall off.

Here, the wafer button 7 has a structure in which the set screw 6 is fastened therein (see FIGS. 3A and 3B).

The present invention is constructed entirely by replacing the elastomer 5a with about 3.5 mil Kapton Tape.

Although the case where the Kapton tape material was used as the insulating film has been described as an example, any material may be used as long as the insulating film is durable and does not deteriorate and particles are not generated.

According to the present invention which acts as described above, the pedestal for oxide dry etching is a material in which the Kapton tape is durable, does not deteriorate, and particles are not generated, thereby preventing particle generation and enabling uniform CD management to manufacture an ultra-high integrated device. This is a problem when it is a problem that can not only solve the decrease in yield, but also maintain the high level of quality and increase the operation rate of the facility, which has the advantage of reducing cost and improving productivity.

Claims (2)

A plurality of pedestal rings 2 that insulate the first face of the pedestal, an elastomer 5a placed over the second face 1 of the pedestal that the wafer contacts, and a second face 1 of the pedestal that holds the wafer. (3,4) between the pedestal ring (2) to be fixed to the) and a set screw provided in a predetermined region of the pedestal ring (2) to prevent falling of the wafer fixed to the second surface (1) of the pedestal In the pedestal for oxide film dry etching consisting of (6) and a wafer button (7), a Kapton tape (instead of the elastomer Elastomer 5a) is used as an insulator between the wafer and the pedestal surface 1 on the pedestal surface 1 on which the wafer is placed. Pedestal for oxide film dry etching, characterized in that the pedestal surface (1) is made of Kapton Tape (5b) to prevent particle generation and to manage uniform crystal size (CD). The pedestal for oxide dry etching as claimed in claim 1, wherein the Kapton tape (5b) is 3.5 mils thick.

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