发明授权
- 专利标题: Method for analyzing impurities within silicon wafer
- 专利标题(中): 分析硅晶片杂质的方法
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申请号: US08714563申请日: 1996-09-16
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公开(公告)号: US06174740B1公开(公告)日: 2001-01-16
- 发明人: Yutaka Ohta , Hirofumi Nishijo , Akira Kosugi
- 申请人: Yutaka Ohta , Hirofumi Nishijo , Akira Kosugi
- 优先权: JP7-264743 19950918
- 主分类号: H01L21302
- IPC分类号: H01L21302
摘要:
A method for analyzing impurities within a silicon wafer in a convenient and simple manner with high accuracy and sensitivity. In a first example 1, a silicon wafer is subjected on its surface to a sandblasting process with use of powder of SiO2 and then to a thermal oxidation process in a dry-oxygen gas atmosphere to easily move impurities present within the silicon wafer into a distorted layer and to form a thermal oxide film and a surface layer of the wafer positioned directly therebelow and containing the distorted layer. The thermal oxide film or the surface layer containing the distorted layer is dissolved with, e.g., a solution of hydrofluoric acid to recover and analyze the dissolved solution. In a comparative example 1, the same processes as in the example 1 are carried out to analyze a predetermined solution, except that the sandblasting process is omitted. In a comparative example 2, the same processing steps as in the example 1 are carried out to analyze a predetermined solution, except that the formation of the thermal oxide film is replaced by a native oxide film without applying any heat. In both of the comparative examples 1 and 2, neither Ni nor Cu is detected; whereas, in the example 1, an Ni content is 100×1010 atoms/cm2 and a Cu content is 1×1010 atoms/cm2.