KR102034901B1

KR102034901B1 - Method for Cleaning Process Chamber

Info

Publication number: KR102034901B1
Application number: KR1020130085957A
Authority: KR
Inventors: 강동호
Original assignee: 에스케이실트론 주식회사
Priority date: 2013-07-22
Filing date: 2013-07-22
Publication date: 2019-11-08
Also published as: KR20150011117A

Abstract

The present invention relates to a method for cleaning epitaxial growth of a wafer in a process chamber and cleaning the process chamber, the cooling fan being provided on the upper side of the process chamber to lower the temperature of an adjacent region. Reducing the power by a predetermined value, thereby increasing the temperature of the upper lid, introducing HCL gas into the process chamber, and increasing the flow rate of hydrogen gas introduced into the chamber by a predetermined value; Performing a cleaning on the process chamber. Therefore, by adjusting only the power of the cooling fan without setting a separate condition for cleaning the process chamber, it is possible to efficiently remove the process by-products deposited around the upper cover inside the process chamber.

Description

Method for Cleaning Process Chamber

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cleaning a process chamber for depositing an epi layer on a semiconductor wafer, and more particularly, to a method for improving the etching efficiency of an upper lid of a process chamber.

In general, semiconductor devices are formed through a series of processes that selectively and repeatedly perform processes such as photolithography, etching, diffusion, chemical vapor deposition (CVD), ion implantation, and metal deposition on a wafer. do. The deposition process in these semiconductor device manufacturing processes is for forming a film quality required on a wafer. However, during the deposition process for forming the film, film or by-products are deposited not only in a desired region on the wafer but also in the chamber in which the deposition is performed.

The deposits deposited inside the deposition chamber are peeled off as the thickness increases, causing particle generation. The particles thus generated enter the film formed on the wafer or adhere to the film surface to act as a cause of the defect of the device, thereby increasing the defective rate of the product. Therefore, it is necessary to remove the film deposited inside the apparatus before the deposit is peeled off.

In the deposition chamber of a conventional deposition facility, deposits accumulate on the inner wall of the chamber or on the surfaces of components within the chamber during the deposition of phase change material on each wafer, and after the deposition process for a given number of wafers Or delamination of the deposits on the surfaces of the internal parts begins to appear. Therefore, the cleaning process for regularly removing the deposits from the inside of the chamber should be performed by using the deposition process time for a predetermined number of wafers as the cleaning cycle.

If the cleaning is performed without considering the temperature of the upper cover in the conventional cleaning process as described above, the etching efficiency of the silicon deposit deposited on the sidewall and the upper liner of the upper cover is reduced. As a result, silicon deposits remain in the process chamber, additional costs are required for cleaning, and process costs are increased due to purchase of consumables replaced by corrosion.

Repeating this cleaning operation every time with a predetermined number of wafer cycles not only reduces the cleaning efficiency of the process chamber but also adversely affects the quality of the wafers deposited in the incompletely cleaned process chamber, which reduces productivity. Cause.

In order to solve the above problems, the present invention is to propose a cleaning method that can maximize the cleaning efficiency for the process chamber by controlling the temperature of the upper cover when cleaning the inside of the process chamber.

The present invention relates to a method for cleaning epitaxial growth of a wafer in a process chamber and cleaning the process chamber, the cooling fan being provided on the upper side of the process chamber to lower the temperature of an adjacent region. Increasing the temperature of the top cover by reducing power by a predetermined value; Introducing HCL gas into the process chamber; And increasing the flow rate of hydrogen gas introduced into the chamber by a predetermined value to perform cleaning of the process chamber by gas phase etching.

According to the present invention, by controlling the power of the cooling fan without setting a separate condition for cleaning the process chamber, it is possible to efficiently remove the process by-products deposited around the upper cover inside the process chamber.

In addition, the time required for cleaning can be shortened to improve the operation rate of the deposition equipment and to secure stable process conditions.

And, by adjusting the amount of the carrier gas, it is possible to improve the etching effect inside the process chamber to the maximum, it is possible to reduce the defects due to the generation of particles in the process chamber.

1 is a cross-sectional view showing a wafer deposition apparatus according to an embodiment of the present invention.
2 is a graph showing a temperature change of the upper cover according to an embodiment of the present invention
Figure 3 is a graph showing the H2 flow rate in accordance with an embodiment of the present invention

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a wafer deposition apparatus.

Referring to FIG. 1, the process chamber is configured substantially symmetrically and includes an upper lid 10, a lower lid 20, and sidewalls surrounding the reactor space, such as epitaxial growth for a semiconductor wafer housed therein. The process is carried out. The semiconductor wafer 5 to be subjected to deposition such as epitaxial growth is held by the susceptor 11 disposed in the reactor space.

A radiant heating system for heating the semiconductor wafer to a particular deposition temperature is placed above the top cover 10 and below the bottom cover 20. It is also provided with an inlet 12 for introducing the process gas into the process chamber and an outlet 13 for discharging the gaseous product of the process gas and the process gas from the process chamber through the sidewall of the process chamber.

The process chamber furthermore comprises a cooling system for cooling the top cover 10 and the bottom cover 20, such as a cooling fan 30, and a heat exchanger 31, which cooling system comprises a top cover 10 and a bottom. Cooling gas is guided to the lid 20, the heat exchanger absorbing heat from the cooling gas being heated in contact with the lid. The cooling system may be provided for controlling the temperature of the top cover of the process chamber.

The sensor 25 may be provided on the upper cover 10 or the lower cover lower 20 to control the temperature performed in the epitaxial growth process. The sensor 25 is preferably a pyrometer, by which the temperature of the upper lid 10 is measured in a non-contact manner. The controller 35 for controlling the temperature of the top cover to a predetermined target temperature for the optimization of the deposition process depends on the difference between the target temperature and the temperature measured by the sensors 25, 26. Is formed to affect the power.

The cooling fan 30 is provided above the process chamber, is formed on the side wall of the cooling system surrounding the upper cover and the lower cover, each lamp 21, 22, 23, 24 to transfer heat into the process chamber Cooling is performed while rotating at a preset speed to prevent overheating.

An etching reaction performed to clean the inside of the process chamber may be efficiently performed at 1100 ° C. or more. Before the etching process for cleaning the process chamber, the temperature of the susceptor is easily increased, but the inner wall of the chamber and the area around the top cover take time to increase the temperature, which reduces the etching efficiency of the area around the top cover. Process byproducts may be deposited.

The present invention proposes a method of further improving the cleaning effect inside the process chamber by setting the power of the cooling fan 30 described above.

2 is a graph showing a temperature change of the upper cover according to the comparative example and an embodiment of the present invention. Referring to FIG. 2, the etching of the inside of the chamber is conventionally performed without considering the temperature change of the upper cover, wherein the temperature of the upper cover starts at about 320 ° C. and rises to 440 ° C. FIG.

1 and 2, the cooling fan 30 is specifically a device for preventing overheating of the outer wall of the upper and lower covers and the upper lamps 21 and 22 and the lower lamps 23 and 24 of the 300 mm Centura equipment. As a heat exchanger 31 in the form of a radiator, the rotation speed of the cooling fan 30 can be adjusted by setting the power of the cooling fan 30 according to a user's selection.

In the embodiment of the present invention by reducing the power of the cooling fan 30 by a predetermined value to allow a small flow rate of cooling air is circulated, it is possible to reduce the cooling effect of the upper and lower process chambers. Due to the lowering of the cooling effect, the temperature of the region around the upper cover 10 is increased. The minimum value of the ambient temperature of the upper cover 10 at the time of heating up before the cleaning of the process chamber may be set to 350 ° C, that is, the initial temperature value of the upper cover before the cleaning process of the upper cover through power reduction of the cooling fan 30 may be set to 350 ° C. . The temperature around the top cover 10 may rise from an initial 350 ° C. to 470 ° C. through an elevated temperature inside the chamber for the etching process.

That is, before the etching process for cleaning the process chamber as described above, the temperature of the region around the upper lid 10 is reduced by reducing the power of the cooling fan 30 by a predetermined value in the step of raising the temperature of the process chamber. The average temperature rises by 30 ° C or more.

As a result, decomposition of HCL contained in the reaction gas for etching is activated, and silicon complex is deposited on the upper liner 11 located at the periphery of the upper lid 10, particularly the exhaust port 13 of the reaction gas. The deposition can be prevented.

3 is a graph showing the H2 flow rate according to the embodiment of the present invention.

Referring to FIG. 3, when the H 2 gas is injected into the process chamber, the graph shows the etching rate according to the flow rate of the H 2 gas. The abscissa indicates the inflow direction of the H 2 gas with respect to 0, and the − direction indicates the H 2 gas. The diffusion direction is shown. Specifically, the + direction may be the inlet 12 through which the reaction gas is introduced, and the − direction may be the outlet 13 through which the reaction gas is discharged.

When the carrier gas, H2 gas, is introduced into the upper and lower directions of the wafer, the H2 gas, which is a carrier gas, serves to diffuse the reaction gas, HCL gas, into the process chamber. At this time, the farther away from the point where the HCL gas is injected may increase the effect of the etching reaction inside the process chamber. In particular, in order to perform etching to the upper liner 11 around the upper lid, it is necessary to adjust the amount of H 2, which is a carrier gas.

Therefore, the graph of FIG. 3 shows the results of experimenting with H2 gas at a flow rate in three cases, and when H2 gas was injected by 8slpm in the upper direction and 8slpm in the lower direction (8/8), 30slpm in the upper direction of the wafer, The case where 20slpm is injected in the lower direction (30/20), 60slpm in the wafer upper direction and 20slpm in the lower direction (60/20) is shown.

The graph above shows that the etching slope decreases as the amount of H 2 gas flowing into the upper and lower directions of the wafer decreases. That is, when the H 2 gas is injected by 8 slps in the upper direction of the wafer and 8 slps in the lower direction (8/8), the etching slope is drastically reduced. It can be seen that the diffusion distance of the H 2 gas is diffused to a position of about −240 mm in the direction of the gas outlet 13 based on the center of the wafer.

However, in the case where 60slpm is injected in the upper direction of the wafer and 20slpm in the lower direction (60/20), the etching inclination is reduced than in the above case, and the diffusion distance of the H2 gas is based on the center of the wafer. It can be seen that the diffusion to the position of about -320mm in the direction of).

Therefore, as the flow rate of the H 2 gas is increased by a predetermined value, it can be confirmed that the etching reaction of the process chamber can be effectively performed farther from the center of the wafer. That is, the inside of the process chamber can be etched uniformly, and the quality of the wafer deposited in the uniformly etched process chamber can also be improved.

The present invention can prevent deposition of process by-products around the top cover inside the process chamber by adjusting only the power of the cooling fan without setting a separate condition for cleaning the process chamber. Therefore, the time required for cleaning can be shortened to improve the operation rate of the deposition equipment and to secure stable process conditions.

And, by adjusting the amount of the carrier gas, it is possible to improve the etching effect inside the process chamber as much as possible, it is possible to reduce the defects caused by the generation of particles in the process chamber.

The present invention has been described above with reference to the preferred embodiments, which are merely examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component specifically shown in the embodiment of the present invention can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Claims

A method of cleaning epitaxial growth on a wafer in a process chamber comprising a top cover, a bottom cover, and sidewalls, the method comprising:
Increasing the temperature around the upper cover by reducing the power of the first cooling fan only by a predetermined value among the first cooling fan disposed around the upper cover and the second cooling fan disposed around the lower cover; ;
Introducing HCL gas into the process chamber while the temperature around the top cover is increased; And
Cleaning the process chamber by gas phase etching by increasing a flow rate of hydrogen gas introduced into the chamber by a predetermined value;
Including,
And a flow rate of hydrogen gas introduced into the upper direction of the wafer is 1.5 to 3 times the flow rate of hydrogen gas introduced into the lower direction of the wafer.

The method of claim 1,
The method of cleaning the process chamber by reducing the power of only the first cooling fan by a predetermined value, the temperature around the upper cover is increased by 30 degrees or more relative to the initial temperature.

The method of claim 1,
Hydrogen gas flow rate is injected into the lower direction of the wafer is 20slpm,
The flow rate of the hydrogen gas introduced into the upper direction of the wafer is 30slpm to 60slpm cleaning method of the process chamber.