Process for forming self-aligned metallization patterns for semiconductor devices

Claim 1

Method for forming self-aligned metallization for semiconductor devices comprising the following steps: forming a first insulating layer (22; 56) on the surface of a monocrystalline silicon substrate (10, 45), whose coefficient of expansion is similar to that of the substrate; forming a second insulating layer (24; 58) over said first layer; forming a polycrystalline silicon layer (26; 52) over said second layer; forming a third insulating layer (27; 54) over said polycrystalline silicon layer; removing said third insulating layer and said polycrystalline silicon layer down to said second insulating layer to produce substantially vertical sidewalls on the remaining third insulating layer and polycrystalline silicon layer; wherein the said removing of said third insulating layer and polycrystalline silicon layer is in areas designated to be at least source/drain regions of field effect transistor devices or emitter regions of bipolar devices; thermally oxidizing the exposed sidewalls of said polycrystalline silicon layer to produce a silicon dioxide sidewall layer (30; 60; 69; 70) thereon; removing the exposed said second insulating layer; forming the source/drain regions (62; 74) or the emitters (34), respectively, in the areas of said silicon substrate under the removed portions; removing the remaining said third insulating and polycrystalline silicon layers to leave the remaining portions of said silicon dioxide sidewall layer extending above said silicon substrate; forming openings in said first insulating layer to the elements of said field effect transistor devices or bipolar devices, respectively; and forming a substantially planar conductive layer (40, 42, 44, 46; 64, 66, 68; 76, 78, 80) on said silicon body which has portions thereof electrically separated by said silicon dioxide sidewall layer (30; 60; 69, 70), for contacting the said elements of said field effect transistor devices or bipolar devices, respectively.