JPS6411346A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent faulty electrical connection between upper and lower layers of an insulating film as well as the etching development of the base surface at the bottom part of a hole by forming an electric conductor at a part wherein electrical connection is performed before completing the formation of the insulating film. CONSTITUTION:A thin insulating film is formed on a substrate wherein a Si substrate 1, a lower layer oxide film 2, a gate oxide film 3, the first layer interconnection 4 and so forth are formed and a hole is opened at a required place of the insulating film 5. Then, electric isolation between an electric conductor to be formed next and the first layer interconnection 4 and the like takes place and no failure of them develops. Among places wherein the hole is opened at the base insulating film 5, polySi 6 is formed at a place wherein its height is low and it makes the final hole 9 deep. After forming insulating films 7 on polySi 6, the hole 9 for use in connection is opened and an upper interconnection 8 is formed. The depth of the hole 9 becomes shallow and its state makes connection with the upper interconnection 8 sure and even if the Si surface is scraped, no problems such as fluctuations in the surface concentration of impurities and the like arise. Further, when a film wherein the thickness of an upper part of its insulating film varies according to the base form is used as the insulating films 7, the thickness of the insulating film is easily controlled by forming polySi 6 which is extruded at a lower part of substrate surface.