Method of manufacturing epitaxial silicon wafer

Abstract

A role of a bottom face of a silicon wafer is identified in a manufacturing process of the silicon wafer. And preferable characteristic feature is also identified. In order to obtain the above characteristic feature, a process method to be implemented into the method of manufacturing a normal silicon wafer is provided. For example, the method comprises: a pre-cleaning process for cleaning the silicon wafer having top and bottom faces processed to a mirror finish; and a rapid thermal process or an epitaxial growth process, wherein the pre-cleaning process comprises a hydrofluoric acid (HF) process and a subsequent pure water (DIW) process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section view showing a general appearance of a susceptor.

FIG. 2 is a schematic view of an epitaxial wafer manufacturing device.

FIG. 3 is a drawing showing a flow chart of an example.

FIG. 4 is a drawing showing a flow chart of a comparative example.

FIG. 5 is a drawing showing a temperature diagram in an epitaxial growth process and a hydrogen annealing process.

FIG. 6 is a drawing showing schematically a bottom face of a silicon epitaxial wafer obtained in a process of an example.

FIG. 7 is a drawing showing schematically a bottom face of a silicon epitaxial wafer obtained in a process of a comparative example.

FIG. 8 is a drawing showing a graph indicating numbers of particles on a bottom face of a wafer obtained by an epitaxial growth.

FIG. 9 is a drawing showing a graph indicating HAZE level of the bottom face of the wafer obtained by an epitaxial growth.

Claims

1. A method of manufacturing a silicon wafer comprising the steps of: cleaning a silicon wafer with top and bottom faces processed to a mirror finish; and conducting a rapid thermal process (RTP) or an epitaxial growth process, wherein the cleaning step comprises: processing the silicon wafer with hydrofluoric acid (HF); and subsequently processing the silicon wafer with pure water (DIW) in a last stage of the cleaning step.

2. The method of manufacturing the silicon wafer according to claim 1 wherein the processing step with the hydrofluoric acid (HF) and the subsequently processing step with the pure water (DIW) are applied to the bottom face opposite to the top face for a device processing.

3. The method of manufacturing the silicon wafer according to claim 1 wherein the cleaning step further comprises: processing the silicon wafer with aqueous ozone solution to oxidize a surface thereof before the processing step with the hydrofluoric acid (HF) and the subsequently processing step with the pure water (DIW).

4. The method of manufacturing the silicon wafer according to claim 2 wherein the cleaning step further comprises: processing the silicon wafer with aqueous ozone solution to oxidize a surface thereof before the processing step with the hydrofluoric acid (HF) and the subsequently processing step with the pure water (DIW).

5. A silicon wafer utilized in a rapid thermal process (RTP) or an epitaxial growth process comprising: top and bottom faces thereof processed to a mirror finish and oxidized to form protective oxide films, respectively, wherein the protective oxide film on the bottom face is easier to remove compared to the protective oxide film on the top face.

6. The silicon wafer according to claim 5 wherein the protective oxide film on the bottom face is formed in a process with hydrofluoric acid (HF) and a subsequent process with pure water (DIW).

7. The silicon wafer according to claim 5 wherein the protective oxide film on the top face is formed in a process with aqueous ozone solution.

8. The silicon wafer according to claim 6 wherein the protective oxide film on the top face is formed in a process with aqueous ozone solution.