JPH09199424A - Epitaxial growth method - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To reduce the cycle time in an epitaxial growth method. An etching step of introducing an etching gas into a chamber not containing a silicon wafer to etch the surface of a susceptor on which the wafer is placed, and introducing a gas for forming a film into the chamber. Coating step of forming a coating on the surface of the susceptor,
What is claimed is: 1. An epitaxial growth method comprising: a cleaning treatment step of cleaning a main surface of a wafer on the susceptor in a chamber; and an epitaxial growth step of forming a silicon epitaxial layer on the main surface of the wafer, wherein a processing temperature of the etching processing. And the processing temperature of the coating process is 1
The temperature is set to the same temperature as 000 ° C., and the processing temperature for the cleaning and the processing temperature for the epitaxial growth are set to the same temperature as 1000 ° C. The degree of vacuum in the etching process and the cleaning process is set to 600 to 700 Torr, and to 80 Torr in other processes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial growth method, for example, a technology effectively applied to an epitaxial growth technology for growing a silicon epitaxial layer (semiconductor layer) on the surface (main surface) of a semiconductor substrate made of silicon.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device such as an IC, there is a step of growing an epitaxial growth layer (epitaxial layer) on a main surface of a semiconductor substrate (semiconductor wafer). The growth of the epitaxial layer is formed by an epitaxial growth method.

As one of the epitaxial growth apparatuses, a single-wafer type epitaxial growth apparatus (single wafer chamber system) for continuously forming an epitaxial growth layer on the surface of a wafer is known. The single-wafer type epitaxial growth apparatus is described, for example, in "Electronic Materials", March 1990 issue, published by the Industrial Research Society, P30 to P33, issued March 1, 1990.

Further, P200 to P203, "Latest LSI Process Technology" issued by the Industrial Research Group, January 20, 1991, describe epitaxial growth cycle examples (SiH ₄ system). In this example of the process cycle, the wafer surface is cleaned by reducing SiO _{2 on} the surface of the wafer in hydrogen at a high temperature of 1200 ° C., and then epitaxially grown at a temperature of 1050 ° C. to form an epitaxial layer.

In this epitaxial growth cycle example,
The reduction of the surface SiO ₂ by baking H ₂ after raising the temperature in the chamber to a predetermined temperature and the surface cleaning by HCl change the processing time depending on the etching amount, but are set to, for example, 10 minutes. Further, the time required to shift from the etching process to the epitaxial growth process is set to 10 minutes. The time of 10 minutes is a time required to lower the temperature in the chamber to a predetermined temperature, and is also a time spent for removing the halogen component in the chamber by HCl purging.

[0006]

An epitaxial growth method for forming a silicon epitaxial layer on a main surface of a silicon substrate using a single-wafer type epitaxial growth apparatus is to clean the main surface of a wafer in a chamber (cleaning process step: After the pretreatment), an epitaxial layer is formed on the main surface of the wafer by epitaxial growth (epitaxial growth step).

[0007] In the cleaning process, H
_The carrier gas consisting of _{2 is} flown for several minutes to remove S from the wafer surface.
The main surface of the wafer is cleaned by reducing iO ₂ . In the epitaxial growth step, a carrier gas and a reaction gas such as monosilane or dichlorosilane are introduced into the chamber to grow a silicon epitaxial layer on the main surface of the wafer.

On the other hand, by the epitaxial growth process,
Silicon also adheres to the surface of the susceptor on which the wafer is placed. Therefore, cleaning is performed before performing the epitaxial growth process. In this cleaning process, silicon attached to the surface of the susceptor is etched and removed (etching step: pretreatment), and then the surface of the susceptor is covered with a film (coating step).

In the etching step, for example, an etching gas such as HCl is introduced into the chamber to etch the silicon film adhered to the surface of the susceptor or the like.
Further, in the coating step, a carrier gas and monosilane, dichlorosilane, or the like are introduced into the chamber, and the surface of the etched susceptor is covered with a polysilicon film having a predetermined thickness.

During the cleaning and the formation of the epitaxial layer, the chamber is closed prior to the processing,
The temperature and vacuum in the chamber are controlled to reach the desired setpoints.

In the conventional epitaxial growth method, the processing temperature of the pretreatment for cleaning and the epitaxial layer formation is higher than the processing temperature of the main treatment.

For example, FIG. 4 shows an example of a process cycle by the conventional epitaxial growth method. As shown in the process time chart of FIG. 4, cleaning including etching and coating is performed, and thereafter, epitaxial layer formation including cleaning and epitaxial growth is performed.

The processing temperature is 115 in the case of etching processing.
0 ° C., 1000 ° C. for coating treatment, 1100 ° C. for cleaning treatment, 10 for epitaxial growth treatment
It will be 00 ° C. Also, the vacuum degree in the chamber during processing is
The etching treatment, the coating treatment, the cleaning treatment, and the epitaxial growth treatment are all about 80 Torr.

In such a conventional epitaxial growth method, since the processing temperature of the chamber is changed during the cleaning and the formation of the epitaxial layer, a transition time (a, b) is required to reach each temperature condition. The reduction of the cycle time of the process is hindered, and the throughput is lowered to increase the cost for forming the epitaxial layer.

An object of the present invention is to provide an epitaxial growth method capable of shortening the cycle time of the process.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0017]

The following is a brief description of an outline of typical inventions disclosed in the present application.

(1) An etching step of introducing an etching gas into a chamber that does not contain a semiconductor substrate (silicon substrate) to etch the surface of a susceptor on which the semiconductor substrate is placed, and a coating film in the chamber. A coating step of introducing a forming gas to form a film on the surface of the susceptor, a cleaning treatment step of cleaning the main surface of the semiconductor substrate on the susceptor in a chamber, and a main surface of the semiconductor substrate. An epitaxial growth method having an epitaxial growth step of forming an epitaxial layer (silicon epitaxial layer), wherein a processing temperature of the etching process and a processing temperature of the coating process are 100.
The temperature is set to the same temperature as 0 ° C., and the processing temperature for the cleaning and the processing temperature for the epitaxial growth are set to the same temperature as 1000 ° C. The degree of vacuum in the etching process and the cleaning process is set to about 600 to 700 Torr, and the degree of vacuum in the coating process and the epitaxial growth process is set to about 80 Torr.

According to the means (1), the etching effect can be enhanced by setting the vacuum degree in the chamber at the time of the etching process in the cleaning process (a) to 600 to 700 Torr from the conventional 80 Torr. The temperature can be the same as the low processing temperature of the coating process, it is not necessary to lower the processing temperature during the cleaning process, and the cycle time of the process can be shortened.

(B) By setting the degree of vacuum in the chamber during the cleaning process in the epitaxial layer formation process to 600 to 700 Torr from the conventional 80 Torr, the reduction effect of SiO ₂ can be enhanced, so that the processing temperature is epitaxially grown. The treatment temperature can be the same as the low treatment temperature, and it is not necessary to lower the treatment temperature during the epitaxial layer forming treatment, and the cycle time of the process can be shortened.

(C) From the above (a) and (b), the cycle time of the process can be shortened by shortening the cleaning treatment time and the epitaxial layer forming treatment time.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

FIG. 1 is a flow chart showing an epitaxial growth method according to one embodiment of the present invention, FIG. 2 is a process time chart showing a cycle time of a process in the epitaxial growth method of this embodiment, and FIG. 3 is a process time chart of the epitaxial growth method of this embodiment. It is a schematic diagram which shows the outline of a chamber.

The epitaxial growth method of this embodiment is
As shown in the flow chart of FIG. 1, after starting the processing work,
Etching, coating, cleaning, and epitaxial growth are performed to form a silicon epitaxial layer on the main surface of a silicon wafer (semiconductor substrate).

When the silicon epitaxial layer 2 is formed on the main surface of the silicon wafer 1, the silicon wafer 1 is placed in a chamber (process chamber) 4 as shown in FIG. The chamber 4 includes a chamber main body 5 and a quartz lid 6 that closes the upper portion of the chamber main body 5.

A susceptor 7 is arranged in the center of the chamber body 5. The susceptor 7 is supported by a support shaft 9.

A gas supply pipe 10 for supplying a predetermined gas into the chamber 4 is attached to the peripheral wall of the chamber body 5. From the gas supply pipe 10, each gas sent from a gas supply system (not shown) is supplied into the chamber 4. For example, from the gas supply pipe 10, H ₂ is used as carrier gas and H _{2 is used} as etching gas.
Cl, monosilane, dichlorosilane, or the like as a coating gas is supplied into the chamber 4.

An exhaust pipe 11 connected to a vacuum exhaust system (not shown) is attached to the bottom of the chamber body 5. Due to the exhaust from the exhaust pipe 11, the inside of the chamber 4 is maintained at a predetermined degree of vacuum. For example, in the case of etching and cleaning, the degree of vacuum is 600 to 700.
The degree of vacuum is set to about Torr and the degree of vacuum is 80 Torr for coating and epitaxial growth.
It is set to a degree.

The lamp 1 is provided outside the chamber 4.
2 is provided with a reflector 13 on the back surface thereof,
It is designed to control the temperature inside. The temperature in the chamber 4 is, as shown in the process time chart of FIG.
The etching treatment, coating treatment, cleaning treatment and epitaxial growth treatment all have the same temperature of 1000 ° C.

The lid 6 of the chamber 4 is opened when the silicon wafer 1 is loaded and unloaded, and the silicon wafer 1 is loaded onto the susceptor 7 in the chamber 4 by a transport mechanism (not shown) and is unloaded from the susceptor 7.

Next, the epitaxial growth method will be described. First, the chamber 4 not containing the silicon wafer 1 is closed and cleaning is performed. That is, after closing the chamber 4, the inside of the chamber 4 is heated by the lamp 12 to set the processing temperature to 1000 ° C. At the same time, the vacuum exhaust system is operated to adjust the vacuum degree in the chamber 4 to 60 degrees.
Set to about 0 to 700 Torr.

Next, an etching gas such as HCl is introduced into the chamber 4 through the gas supply pipe 10 and is subjected to an etching treatment for several minutes to remove silicon adhering to the surface of the susceptor 7 and the inner wall of the chamber 4.

Next, after stopping the supply of the etching gas, a carrier gas is caused to flow to purging the inside of the chamber 4. Further, the vacuum exhaust system is operated to set the degree of vacuum in the chamber 4 to about 80 Torr. After that, for example, monosilane or dichlorosilane as a reaction gas is supplied into the chamber 4 together with a carrier gas to form a film for several minutes, and the surface of the susceptor 7 is covered with a polysilicon film to complete the coating process.

In the etching process, the degree of vacuum is set to 600.
Since the etching effect is enhanced by setting the vacuum to a low level of about 700 Torr, the processing temperature can be lowered from the conventional 1150 ° C. to 1000 ° C. and can be the same as the coating processing temperature. As a result, after the etching, the transition time a for lowering the temperature in the chamber 4 to the coating processing temperature is unnecessary, and the cleaning processing time can be shortened.

After the cleaning process is completed, the silicon wafer 1 is placed on the susceptor 7 in the chamber 4.

Next, the inside of the chamber 4 is heated by the lamp 12 and the processing temperature of 1000 ° C. is set. At the same time, the vacuum exhaust system is operated to increase the degree of vacuum in the chamber 4 to 6
Set to about 00 to 700 Torr.

Next, a carrier gas is flown for several minutes to reduce the SiO ₂ on the surface of the silicon wafer 1 and sublimate it.
The surface of the silicon wafer 1 is cleaned.

Next, the vacuum exhaust system is operated to set the degree of vacuum in the chamber 4 to about 80 Torr. After that, for example, monosilane or dichlorosilane is supplied as a reaction gas into the chamber 4 together with a carrier gas, and an epitaxial growth process is performed for a desired time to form a silicon epitaxial layer 2 having a predetermined thickness on the main surface of the silicon wafer 1. Then, the epitaxial growth process is completed.

In the epitaxial layer forming process consisting of the cleaning process and the epitaxial growth process, in the cleaning process, the reduction effect is improved by setting the vacuum degree to a low vacuum of about 600 to 700 Torr. The temperature can be as low as 1000 ° C. and can be the same as the processing temperature of the epitaxial growth processing. As a result, after the cleaning process, the transition time b for lowering the temperature in the chamber 4 to the epitaxial growth process temperature is unnecessary, and the epitaxial layer forming process time can be shortened.

In the epitaxial growth method of this embodiment, the transition time a for changing the treatment temperature when the etching treatment during the cleaning treatment changes to the coating treatment.
In addition, the process time (process cycle time) can be shortened because the process time (process cycle time) for changing the process temperature from the cleaning process to the epitaxial growth process in the epitaxial layer forming process is unnecessary.

Therefore, the throughput is improved by shortening the epitaxial layer forming time in the semiconductor device manufacturing, and the manufacturing cost of the semiconductor device can be reduced.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example, even if the etching treatment temperature and the coating treatment temperature are not the same and are close to each other, the temperature transition time hardly poses a problem. Similarly, even if the cleaning treatment temperature and the epitaxial growth treatment temperature are not the same and are close to each other, the temperature transition time hardly poses a problem.

Further, it goes without saying that the processing temperature and the degree of vacuum in each processing may be other than those in the above embodiment.

In the above description, the case where the invention made by the present inventor is mainly applied to the technique of forming a silicon epitaxial layer in a silicon wafer, which is the field of application of the background, has been described, but the invention is not limited thereto. For example, it can be applied to a technique of epitaxially growing a compound semiconductor on the main surface of a compound semiconductor substrate.

The present invention is applicable at least to the epitaxial growth technique.

[0046]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

(1) In the epitaxial growth method,
Since the etching treatment temperature and the coating treatment temperature during the cleaning process are the same, the transition time for changing the treatment temperature during the cleaning process is unnecessary, and the cleaning process and the epitaxial growth process during the epitaxial layer formation process are not required. Since the temperatures are the same, the transition time for changing the processing temperature during the epitaxial layer forming process is not required, and the processing time can be shortened, so that the throughput is improved and the cost of the epitaxial wafer can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing an epitaxial growth method which is an embodiment of the present invention.

FIG. 2 is a process time chart showing a cycle time of a process in the epitaxial growth method of the present embodiment.

FIG. 3 is a schematic diagram showing an outline of a chamber in the epitaxial growth method of the present embodiment.

FIG. 4 is a process time chart showing a cycle time of a process in a conventional epitaxial growth method.

[Explanation of symbols]

1 ... Silicon wafer, 2 ... Silicon epitaxial layer,
4 ... Chamber, 5 ... Chamber body, 6 ... Lid, 7 ... Susceptor, 9 ... Spindle, 10 ... Gas supply pipe, 11 ... Exhaust pipe, 1
2 ... Lamp, 13 ... Reflector.

Claims (5)

[Claims] 1. An epitaxial growth method comprising: a cleaning treatment step of cleaning a main surface of a semiconductor substrate in a chamber; and an epitaxial growth step of forming an epitaxial layer on the main surface of the semiconductor substrate. And the processing temperature for the epitaxial growth are set to the same or substantially the same temperature. 2. The degree of vacuum in the cleaning process is 600 to 70.
The epitaxial growth method according to claim 1, wherein the epitaxial growth process is set to about 0 Torr, and the vacuum degree of the epitaxial growth process is set to about 80 Torr. 3. An etching step of introducing an etching gas into a chamber not containing a semiconductor substrate to etch the surface of a susceptor on which the semiconductor substrate is mounted, and a gas for forming a film in the chamber. A coating step of introducing and forming a film on the surface of the susceptor;
An epitaxial growth method comprising: a cleaning treatment step of cleaning a main surface of a semiconductor substrate on the susceptor in a chamber; and an epitaxial growth step of forming an epitaxial layer on the main surface of the semiconductor substrate, the etching processing being performed. The temperature and the treatment temperature of the coating treatment are set to the same or substantially the same temperature, and the treatment temperature of the cleaning and the treatment temperature of the epitaxial growth are set to the same or substantially the same temperature. 4. The vacuum degree of the etching process and the cleaning process is set to about 600 to 700 Torr, and the vacuum degree of the coating process and the epitaxial growth process is set to about 80 Torr. Epitaxial growth method. 5. The epitaxial growth method according to claim 1, wherein a silicon epitaxial layer is formed on the main surface of the silicon substrate.