| 摘要 |
PURPOSE:To obtain a W gate electrode or the like having preferable step coverage and adapted for a speed acceleration by forming a groove on a semiconductor substrate, forming an insulating film at least on the surface of the groove, retaining a space in the groove, and growing by a CVD W under the condition of irradiating an Hg lamp. CONSTITUTION:A forming method for a groove 3 normally having 1.0mum or less of width and 1-10mum of depth is conducted by normal anisotropic etching. An SiO2 film 2 formed on the groove is thinly formed 50-1000Angstrom of thickness by thermally oxidizing the whole face of a silicon substrate 1 after forming the groove 3, and W is buried in a space 4 remaining inside the groove. A nitride film may be used instead of the SiO2 film as an insulating film in the groove. Thus, the substrate formed with a groove (trench) structure is introduced into an Hg lamp irradiation type CVD device, and optically conducted by a CVD. In order to perform the irradiating effect with the Hg lamp, it must be conducted at a time for alleviating the selectivity of the SiO2 for the growth of the W, a W film 8 is formed on the whole face of the film 2 and preferably filled in the groove, thereby improving its step coverage.
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