| US 7,569,413 B2 | ||
| Method of forming thin film structure with tensile and compressed polysilicon layers | ||
| Takashi Kasai, Nara (Japan); and Shuichi Wakabayashi, Nara (Japan) | ||
| Assigned to OMRON Corporation, Kyoto (Japan) | ||
| Filed on Feb. 07, 2007, as Appl. No. 11/703,444. | ||
| Claims priority of application No. 2006-044870 (JP), filed on Feb. 22, 2006. | ||
| Prior Publication US 2007/0196946 A1, Aug. 23, 2007 | ||
| Int. Cl. H01L 21/00 (2006.01); H01L 21/425 (2006.01) | ||
| U.S. Cl. 438—53 [438/530; 257/E29.324] | 2 Claims |
| 1. A method for forming a thin film structure, which includes a lower film and an upper film, on a substrate, comprising:
a step of forming the lower film that includes a polysilicon film on the substrate,
a step of making the lower film to be conductive by doping an impurity into the lower film and thermally diffusing the impurity,
a step of forming the upper film that includes a second polysilicon film on the lower film, the upper film being nonconductive
and having a first tensile stress in approximately a same level as a compressive stress of the lower film, and
a step of separating the thin film structure from the substrate by a first etching, leaving at least a part of a periphery
of the thin film structure held by the substrate,
wherein the thin film structure as a whole is adjusted to have a final tensile stress, and
wherein after the impurity is doped into the lower film, an anti-defect film is formed on a top of the lower film before the
impurity is thermally diffused.
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