JP2013089682A - Manufacturing method of epitaxial wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an epitaxial wafer capable of shortening the heat-up time before vapor phase growth while reducing adhesion of wall deposition.SOLUTION: In the method of manufacturing an epitaxial wafer by performing vapor phase growth of an epitaxial layer on the principal face of a wafer mounted on a susceptor, by using a vapor phase growth apparatus of cold water type including the susceptor where the wafer is mounted in a chamber, the susceptor is brought close to the inner wall of the chamber during heat-up before vapor phase growth. Subsequently, temperature in the chamber is raised and the susceptor is returned back to an original position. Thereafter, vapor phase growth is carried out thus manufacturing an epitaxial wafer.

Description

  The present invention relates to a method for manufacturing an epitaxial wafer using a vapor phase growth apparatus.

In the production of a silicon epitaxial wafer by a general vapor phase growth, Si is epitaxially grown using a gas such as SiCl ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , or SiH ₄ which is H ₂ and Si source gas.

  The epitaxial growth reaction is often performed at a relatively high temperature of 900 ° C. to 1200 ° C. by lamp heating or the like. Many epitaxial growth apparatuses are of a cold wall type, and the process is performed while cooling chamber structure members such as quartz and SUS (stainless steel) by water cooling and air cooling.

  Although the epitaxial growth reaction of Si occurs on the wafer, the reaction also occurs on the chamber structure member, and polysilicon or polychlorinated silane is deposited as a by-product. A large amount of polysilicon is deposited mainly on the susceptor that supports the wafer and on the gas flow path around the susceptor. Some of them also deposit on the inner wall of the chamber, and this is generally called a wall deposit. Polysilicon and wall deposits need to be removed periodically, and removal by vapor phase etching with HCl is used.

  It has been demonstrated that wall depots are less likely to occur as the chamber inner wall gets hotter.

  In a cold wall reactor, the temperature of the susceptor easily rises, but it takes time to raise the temperature of the inner wall of the chamber. In some cases, the temperature cannot be sufficiently increased. Since the temperature of the susceptor can be easily raised to 1100 ° C. or higher where the epitaxial growth reaction can be efficiently advanced, the vapor phase growth reaction can be promptly advanced. However, the temperature of the inner wall of the chamber cannot be increased compared to the susceptor. Therefore, it is necessary to wait for the chamber inner wall temperature to rise even after the susceptor temperature rises to a predetermined temperature.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an epitaxial wafer manufacturing method capable of shortening the temperature raising time before vapor phase growth and reducing wall deposition.

The present invention has been made to solve the above-described problems, and was placed on the susceptor using a cold wall type vapor phase growth apparatus having a susceptor for placing a wafer in a chamber. A method for producing an epitaxial wafer by vapor-phase-growing an epitaxial layer on a main surface of a wafer,
When the temperature rises before the vapor phase growth, the susceptor is brought close to the inner wall of the chamber, the temperature of the inner wall of the chamber is raised, the susceptor is returned to the original position, and then the vapor phase growth is performed. An epitaxial wafer manufacturing method characterized by manufacturing a wafer is provided.

  In this way, if the temperature of the chamber inner wall is raised by bringing a susceptor that is easy to heat up, the temperature of the chamber inner wall can be raised quickly, the heating time before vapor phase growth can be shortened, and the adhesion of wall deposits can be reduced. This is a method for manufacturing an epitaxial wafer.

  It is preferable to heat the susceptor to 1100 ° C. or higher when the temperature is raised before the vapor phase growth, and it is preferable to raise the temperature of the chamber inner wall to 500 ° C. or higher by bringing the susceptor closer to the chamber inner wall.

  As a result, the temperature raising time before vapor phase growth can be further shortened, and adhesion of wall deposits can be further reduced.

  At the time of the vapor phase growth, it is preferable that the wafer placed on the susceptor is set to 1050 to 1180 ° C., and the epitaxial layer is vapor grown by supplying a source gas and a carrier gas to the main surface of the wafer.

  Thereby, vapor phase growth reaction can be advanced more appropriately. In particular, since the wall deposit can be reduced in the present invention, the generation of defects based on this can be reduced in the epitaxial layer.

  As described above, according to the epitaxial wafer manufacturing method of the present invention, the heating time before vapor phase growth can be shortened, and the adhesion of wall deposits can be reduced.

It is sectional drawing which shows an example of the single wafer type vapor phase growth apparatus which can be used by this invention. It is a figure which shows the temperature increase rate of the chamber inner wall of an Example and a comparative example.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. As described above, there has been a demand for a method of manufacturing an epitaxial wafer that can shorten the heating time before vapor phase growth and reduce the adhesion of wall deposits.

  As a result of intensive studies on the above problems, the present inventors brought the heated susceptor closer to the inner wall of the chamber and increased the temperature of the inner wall of the chamber, thereby shortening the heating time before vapor phase growth, The present invention was completed by finding that the adhesion of wall deposits can be reduced. Hereinafter, the present invention will be described in more detail.

  In the method for producing an epitaxial wafer of the present invention, a cold wall type vapor phase growth apparatus having a susceptor for placing a wafer W in a chamber is used. FIG. 1 shows an example of a single wafer type vapor phase growth apparatus that can be used in the method for producing an epitaxial wafer of the present invention. As shown in FIG. 1, a cold wall type vapor phase growth apparatus 20 includes a susceptor 2 on which a wafer W is placed in a chamber 1.

  Further, the vapor phase growth apparatus 20 sandwiches the SUS chamber base 3 from above and below, covers the quartz base 4 and 4 ′ forming the chamber 1, and the SUS chamber base provided inside the chamber 1. A susceptor 2 that supports the opaque quartz 5 and 5 'and the wafer W on the upper surface is provided.

  The susceptor 2 is connected to a rotating mechanism 6 and is rotating during vapor phase growth. SUS is used inside the rotation mechanism 6, and a gas introduction pipe 7 for purging the inside of the rotation mechanism 6 is provided. Further, the susceptor 2 is supported by the support structure 10 so as to move up and down, approach the inner wall (the upper transparent quartz member 4) of the chamber 1, and return to the original position.

In the chamber 1, a vapor phase growth gas containing a source gas (for example, SiCl ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₄ , and a dopant gas) and a carrier gas (for example, hydrogen) in the chamber 1 is supplied to the susceptor 2. A vapor phase growth gas introduction pipe 8 is provided which is introduced into the upper region and supplied onto the main surface of the wafer W on the susceptor 2. Further, the chamber 1 is provided with a gas discharge pipe 9 on the side opposite to the side where the vapor phase growth gas introduction pipe 8 is provided.

  The batch-type vapor phase growth apparatus that can be used in the method for producing an epitaxial wafer of the present invention may be any apparatus that allows the susceptor to approach the inner wall of the chamber and return to the original position as described above. .

  In the present invention, the susceptor 2 is brought close to the inner wall of the chamber 1 at the time of temperature rise before vapor phase growth, the temperature of the inner wall of the chamber 1 is raised, and then the susceptor 2 is returned to its original position. Thereby, the susceptor 2 that easily raises temperature helps to raise the temperature of the inner wall of the chamber 1 (inner wall on the susceptor 2 side of the upper transparent quartz member 4), and the temperature raising time before vapor phase growth can be shortened. Further, this sufficiently raises the temperature of the inner wall of the chamber 1 and prevents the wall deposits from adhering.

  Here, bringing the susceptor 2 close to the inner wall of the chamber 1 usually means bringing the susceptor 2 at the position during vapor phase growth closer to the inner wall side of the chamber 1 than the position by the support structure 10 or the like. Returning the susceptor 2 to the original position means returning the approached susceptor 2 to the position at the time of vapor phase growth.

  The heating of the chamber 1 and the susceptor 2 can be performed with a known heating device (not shown). For example, as a heating device for the chamber 1 and the susceptor 2, a so-called lamp heating method is exemplified.

  At this time, it is preferable to heat the susceptor 2 to 1100 ° C. or higher, and it is preferable to bring the susceptor 2 closer to the inner wall of the chamber 1 and raise the temperature of the inner wall of the chamber 1 to 500 ° C. or higher. As a result, the temperature raising time before vapor phase growth can be further shortened, and wall deposits are also reduced.

  Next, the step of vapor-phase growing an epitaxial layer on the main surface of the wafer W will be specifically described. First, the wafer W is put into the chamber 1 adjusted to the charging temperature (for example, 650 ° C.), and is placed on the counterbore on the upper surface of the susceptor 2 so that the main surface thereof faces upward.

  Here, hydrogen gas is introduced into the chamber 1 through the gas introduction pipe 8 and the purge gas introduction pipe 7 for vapor phase growth from the stage before the wafer W is introduced.

  Next, the wafer W on the susceptor 2 is heated to a hydrogen heat treatment temperature (for example, 1050 to 1200 ° C.) by a heating device. At this time, the temperature of the inner wall of the chamber 1 is raised by bringing the heated susceptor 2 closer to the inner wall of the chamber 1 and returning the susceptor 2 to its original position.

  Next, vapor phase etching for removing the natural oxide film formed on the main surface of the wafer W is performed. Note that this vapor phase etching is performed until immediately before the vapor phase growth which is the next step.

Next, the wafer W is set to a desired growth temperature (for example, 1050 to 1180 ° C.), and a source gas (for example, SiCl ₄ , SiHCl ₃ , SiH ₂ ) is formed on the main surface of the wafer W via the gas phase growth gas introduction pipe 8. Cl ₂ , SiH _4, dopant gas, etc.) and carrier gas (for example, hydrogen gas) are supplied to the main surface of the wafer W by supplying a purge gas (for example, hydrogen gas) substantially horizontally through the purge gas introduction pipe 7. An epitaxial wafer can be manufactured by vapor phase growth of the epitaxial layer.

  Finally, the epitaxial wafer is taken out, cooled to a temperature (for example, 650 ° C.), and carried out of the chamber 1.

  Thereafter, as an HCl etching process, the chamber 1 may be heated to 1100 to 1200 ° C., and HCl gas may be flown to remove the poly-Si and polychlorinated silane deposited on the susceptor 2 and the inner wall of the chamber 1.

  At this time, when the temperature of the chamber 1 is raised, the susceptor 2 is raised and brought close to the inner wall of the upper transparent quartz member 4 on the susceptor 2 side. After the temperature rises to a predetermined temperature, the susceptor 2 is returned to the original position. Etching may be performed.

  EXAMPLES Hereinafter, although the Example and comparative example of this invention are given and demonstrated further in detail, this invention is not limited to the following Example.

〔Example〕
A single-phase vapor phase growth apparatus shown in FIG. 1 was prepared. Under a hydrogen atmosphere, the susceptor was heated from 700 ° C. to 1200 ° C. with a heating device, and the heated susceptor was held at 1200 ° C., approaching the inner wall of the chamber, and raising the temperature of the inner wall of the chamber. FIG. 2 shows the result of measuring the temperature change of the inner wall of the chamber with a pyrometer. The horizontal axis of FIG. 2 shows the elapsed time, where 1 is the time until the inner wall of the chamber of the comparative example described later reaches 500 ° C.

Thereafter, the susceptor was returned to the original position, and an epitaxial layer was vapor-phase grown on the main surface of the wafer using SiCl ₄ as a source gas and hydrogen gas as a carrier gas, thereby manufacturing an epitaxial wafer.

[Comparative Example]
A single-phase vapor phase growth apparatus of FIG. 1 was prepared. The temperature in the chamber was raised with a commonly used heater without moving the susceptor. FIG. 2 shows the result of measuring the temperature change of the inner wall of the chamber with a pyrometer.

  Thereafter, an epitaxial layer was vapor-phase grown on the main surface of the wafer under the same conditions as in the example to produce an epitaxial wafer.

  As shown in FIG. 2, the time required for the inner wall of the chamber to reach about 500 ° C. could be shortened. In the example, the time required for the vapor phase growth from the temperature rise was 80% as compared with the comparative example. Furthermore, when the production of the epitaxial wafer was continued under the conditions of the example and the comparative example, the occurrence of defects that might be caused by the wall deposit on the obtained epitaxial wafer was reduced by about 30%.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Chamber, 2 ... Susceptor, 3 ... Chamber base, 4, 4 '... Transparent quartz member, 5, 5' ... Opaque quartz member, 6 ... Rotation mechanism, 7 ... Purge gas introduction pipe, 8 ... Gas introduction for vapor phase growth Tube 9 gas discharge tube 10 support structure 20 vapor phase growth apparatus W wafer

Claims (4)

An epitaxial wafer is manufactured by vapor-phase-growing an epitaxial layer on the main surface of the wafer placed on the susceptor using a cold wall type vapor phase growth apparatus having a susceptor for placing the wafer in a chamber. A method,
When the temperature rises before the vapor phase growth, the susceptor is brought close to the inner wall of the chamber, the temperature of the inner wall of the chamber is raised, the susceptor is returned to the original position, and then the vapor phase growth is performed. A method of manufacturing an epitaxial wafer, characterized by manufacturing a wafer.   The method for producing an epitaxial wafer according to claim 1, wherein the susceptor is heated to 1100 ° C. or higher at the time of temperature rise before the vapor phase growth.   3. The epitaxial wafer production method according to claim 1, wherein the temperature of the inner wall of the chamber is raised to 500 ° C. or more by bringing the susceptor closer to the inner wall of the chamber at the time of temperature rise before the vapor phase growth. Method. At the time of the vapor phase growth, the wafer placed on the susceptor is set to 1050 to 1180 ° C., and the source layer and the carrier gas are supplied to the main surface of the wafer to vapor-phase the epitaxial layer. The manufacturing method of the epitaxial wafer of any one of Claim 1 thru | or 3.

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