| 摘要 |
PURPOSE:To form a wiring part where a fine pattern can be processed and an interconnection is not broken by a method wherein a through hole having an overhang is made in insulating films whose etching rate differs from each other and a stepped through-hole is made in an interlayer insulating-film by making use of these insulating films as masks by an anisotropic etching method. CONSTITUTION:At least two kinds of insulating films 2, 3 whose etching rate differs from each other are formed on an interlayer insulatingfilm 1 formed on a semiconductor substrate in the sequence starting from the film having a higher etching rate. Then, after a mask 4 has been formed on the insulating films 2, 3, the insulating films 2, 3 are etched in succession by an isotropic method, and a through hole 10 having an overhang over the interlayer insulating- film 1 is formed. Then, the interlyaer insulating-film 1 is etched by making use of the insulating films 2, 3 having the through hole 10 as masks by means of an anisotropic etching method. A stepped through-hole 10A is formed on the interlayer insulating-film 1. For example, the PSG film 2 and the SiO2 film 3 by a CVD method are formed in succession on the interlayer insulating-film 1 composed of an Si3N4 film, and are etched with a solution of hydrofluoric acid so as to form the through hole 10.
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