| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing semiconductor device for preventing remaining of a gap at an interface of thermal oxide films that are growing respectively from the upper and lower directions. SOLUTION: A Si layer 13 and a SiGe layer 11 are formed on a Si substrate 1 and a groove h1 is also formed along the external circumference of an element region. Next, a supporting material film is formed on the entire surface of the Si substrate 1 and this film is dry-etched to form a supporting material 22. Subsequently, the Si layer 13/SiGe layer 11 exposed from a lower side of the supporting material 22 is dry-etched. When the SiGe layer 11 is etched under this condition with a hydrofluoric-nitric acid solution, a cavity is formed under the Si layer 13 in such a shape that the Si layer 13 is hanged from the supporting material 22. Thereafter, a thermal oxide film is formed within the cavity with thermal oxidation of the Si substrate 1 (BOX oxidation method). In the process to form the supporting material 22, a warp preventing supporting part 22b is formed to the groove h1 from a part of a longer side of the external circumference of the element region in order to prevent warp of the supporting material 22 in the BOX oxidation process. COPYRIGHT: (C)2008,JPO&INPIT
|
