JPH0620963A - Vacuum thin film deposition equipment - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention significantly improves the heater maintenance work efficiency of a vacuum thin film deposition apparatus having a heater in a vacuum chamber by improving the heater structure. Aim to reduce. [Structure] A heater cover 7 having a structure in which the heater 6 is divided into a plurality of pieces and detachable by operating a stopper 8 or the like without removing the heater 6 from the wall of the vacuum chamber 1 is attached so as to cover the entire surface of the heater 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater structure for improving the maintenance efficiency of a heater in a vacuum thin film deposition apparatus having a heater in a vacuum tank such as a parallel plate type plasma chemical vapor deposition apparatus. .

[0002]

2. Description of the Related Art A conventional parallel plate type plasma chemical vapor deposition apparatus will be described. A plasma chemical vapor deposition apparatus is a device that forms a semiconductor film of a thin film transistor and a gate insulating film for forming an image display device in combination with a liquid crystal, etc., and the product performance depends on how to reduce impurities and particles in the vacuum chamber. It is very important to ensure stable quality.

FIG. 3 is a schematic sectional view showing the structure of a plasma chemical vapor deposition apparatus. To form a thin film on the substrate 3, the material gas containing Si as a main component is introduced into the vacuum chamber 1 through the discharge electrode 4 provided with a large number of holes so that the shower-like gas can be discharged, and the tray 2 and the discharge electrode 4 can be formed. It is obtained by performing plasma discharge between. A substrate 3 whose temperature is controlled to a desired temperature by a heater 6 is set on the tray 2, and active species generated by plasma discharge diffuse into the entire vacuum chamber 1 to form a thin film on the substrate 3 and further at various parts in the vacuum chamber. Deposit. The deposited film adhering to the inside of the vacuum chamber 1 peels off as the accumulated film thickness increases, contaminating the inside of the vacuum chamber 1 and deteriorating the performance and quality of the product. Cleaning for removing the film regularly. is necessary. Plasma gas cleaning is generally used as a method for removing the film, and a gas in which oxygen (O ₂ ) is mixed with a fluorocarbon gas (CF ₄ , ClF ₃ , SF ₆ ) as a cleaning gas instead of the material gas is discharged. It is introduced into the vacuum chamber 1 through the electrode 4. The cleaning gas causes a high-frequency plasma discharge between the heater 6, the electrode (not shown) such as the wall of the vacuum chamber 1 which is grounded, and the discharge electrode 4, and the generated active species reacts with the deposited film to be gasified. And discharge it out of the vacuum chamber 1.

[0004]

However, the conventional techniques have the following problems.

That is, the film attached to the heater cannot be completely removed by only gas cleaning and is gradually accumulated and peeled off to become a source of particles contaminating the inside of the vacuum chamber 1. Further, the active species of the cleaning gas introduced into the vacuum chamber 1 fluorinates the Fe component in the stainless material on the surface of the heater having a high temperature, causing intergranular corrosion. This corrosion product gradually peels off and contaminates the inside of the vacuum chamber. In order to suppress the generation of particles due to this residual film and the generation of corrosion products due to cleaning gas, it is necessary to periodically remove the heater from the wall of the vacuum chamber 1 and replace it. A lot of man-hours were required because it was necessary to confirm later vacuum confidentiality tests. In addition, during that period, the equipment operation rate was lowered due to facility shutdown. The size of vacuum thin film deposition equipment tends to increase year by year with the increase in size and mass production of products, and improving the efficiency of equipment maintenance is an important issue.

[0006]

In order to solve the above problems, a vacuum thin film deposition apparatus of the present invention is a cover having a structure in which a heater is detached from a vacuum chamber wall without being detached from the vacuum chamber wall by operating a stopper or the like. Is attached so as to cover the entire surface of the heater.

[0007]

By covering the heater with the cover as described above, the active species generated during plasma discharge are prevented from reaching the heater surface and the accumulation and corrosion of the residual film on the heater surface are prevented. Also, when maintaining the heater, it is not necessary to remove the heater from the wall of the vacuum chamber, and it is possible to substitute it by simply disassembling and removing the heater cover by attaching and detaching the metal fittings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a parallel plate type plasma chemical vapor deposition apparatus, which uses amorphous Si by using SiH ₄ and other material gases.
An i film / amorphous Si nitride film can be deposited on the substrate. Further, a plasma gas cleaning method using CF ₄ gas is adopted to remove the deposited film in each portion in the vacuum chamber.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a vacuum chamber. At the lower part of the vacuum chamber 1, a discharge electrode 4 having a large number of holes and a square shape of about 800 mm on each side is attached so that gas can be discharged in a shower shape. A heater 6 having the same size as the discharge electrode 4 and a weight of 100 kg is used for controlling the temperature of the substrate 3 set on the tray 2 having substantially the same size as the discharge electrode 4 electrically grounded at the upper portion. Is installed. The heater 6 is provided with a heater cover 7 which is divided into two parts in the horizontal direction in the figure and can be easily removed. At the time of removing the deposited film, a cleaning gas is introduced from the discharge electrode into the vacuum chamber 1 to cause high frequency discharge between the discharge electrode 4 and the counter electrode (tray) 2. The active species generated during discharge react with the deposited film, gasify the film, and exhaust it to the outside of the vacuum chamber.

Next, the operation of this embodiment will be described. When depositing a thin film, the extent to which the active species reach the surface of the heater 6 is significantly reduced by the heater cover 7, the film does not directly adhere to the heater surface, and the heater 6 itself does not need to be removed even when maintenance is required. . Further, the corrosive active species generated during discharge during cleaning spreads throughout the vacuum chamber, but the degree of exposure of the heater 6 to the active species by the heater cover 7 is significantly reduced, and corrosion of the surface of the heater 6 can be suppressed. I can.
Even if the accumulation and corrosion of the deposited film on the heater cover 7 progresses to some extent and the cover has to be replaced, the hook-shaped stopper 8 is removed as shown in FIG. Therefore, it is not necessary to remove the heater 6 from the vacuum chamber wall. Further, since the heater 6 is not removed, it is not necessary to confirm the vacuum airtightness of the vacuum chamber wall and the heater mounting portion after the construction, and the operation can be easily performed in a short time. As a result, as shown in (Table 1), the maintenance time related to the heater, which was conventionally required to be 60 hr / person for one vacuum chamber, can be performed at 4 hr / person after improvement of the cover attachment. .

[0011]

[Table 1]

[0012]

According to the present invention, in the maintenance of the heater, the same performance can be obtained by replacing the cover of the heater instead of the maintenance for removing the heater, and the maintenance work time can be greatly shortened. Although the parallel plate plasma chemical vapor deposition apparatus has been described as an embodiment of the present invention, the present invention does not impair the effect in general vacuum deposition apparatuses having other heating mechanisms.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a parallel plate type plasma chemical vapor deposition apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cover removing method according to an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional plasma enhanced chemical vapor deposition apparatus.

[Explanation of symbols]

 1 Vacuum Tank 2 Tray 3 Substrate 4 Discharge Electrode 5 Tray Conveyor Roller 6 Heater 7 Heater Cover 8 Stopper

Claims (3)

[Claims] 1. A vacuum thin film deposition apparatus having a heater in which a heating element, which is a heating element, is surrounded by a metal plate in a bag shape in a vacuum chamber, and the heater is completely covered by a removable cover. A vacuum thin film deposition apparatus characterized by: 2. The vacuum thin film deposition apparatus according to claim 1, wherein the cover is made of a stainless steel material, is divided into a plurality of pieces by operating a stopper or the like, and is detachable from a heater. 3. A vacuum thin film deposition apparatus according to claim 1, which is a plasma chemical vapor deposition apparatus for forming an amorphous thin film containing Si as a main component.