International Business Machines Corporation

Thomas A Hansen

George R Goth

Robert T Villetto, Jr

John S Lechaton

George A Kaplita

James S Makris

Robert R Wilbarg

Nicholas J Giammarco

James A Bondur

Claude Johnson, Jr

John R Galie

Disclosed is a process for etching semiconductor materials with a high etch rate against an insulator mask using a novel etchant gas mixture. The mixture consists of a chlorocarbon (e.g., CCl.sub.2 F.sub.2, CCl.sub.4 or CCl.sub.3 F), SF.sub.6, O.sub.2 and an inert gas (e.g. He). The preferred gas mixture contains 2/1 ratio of the chlorocarbon to SF6 and the following composition: 1-4% of SF.sub.6, 3-10% of O.sub.2, 74-93% of He and 3-10% of chlorocarbon. The etch rate of silicon (or silicide) against an oxide mask using this etchant gas mixture under normal etching conditions is high, on the order of 30-40. An impressive feature of the process is shape control of trenches by mere manipulation of the RIE system power.

RIE process for etching silicon isolation trenches and polycides with

Disclosed is the use of metal silicide (e.g. Pt-Si) contacts in boron lightly doped P.sup.- type silicon between two contiguous but not adjacent N.sup.+ type regions instead of employing the usual P.sup.+ implanted or diffused channel stoppers. The invention finds a particularly interesting application in polyimide filled deep trench isolated integrated circuits. The trench sidewalls are coated with an insulating material which is removed from the trench bottom at the all contact etch step. The Pt-Si is formed at the bottom of the trenches at the same time that the device contacts are made.

Metal silicide channel stoppers for integrated circuits and method for

Deep trenches (14,15) are formed according to the desired pattern through the N epitaxial layer (13) and N.sup.+ subcollector region (12) into the P.sup.- substrate (11) of a silicon structure (10). Where a substrate contact is needed, the trenches delineate a central stud (16) or mesa of silicon material. Channel stop regions (18) are formed e.g. by ion implantation of boron atoms at the bottom of trenches, SiO.sub.2 and Si.sub.3 N.sub.4 layers (17,19) are then deposited on the whole structure. A substrate contact mask is applied and patterned to selectively expose one side of the trench sidewalls, the bottom of the trenches adjacent thereto and others areas if desired such as the top surface of the stud. The composite SiO.sub.2 /Si.sub.3 N.sub.4 layer is then etched to leave exposed only the sidewalls of the stud, at least partially the bottom of the trenches adjacent thereto and the top surface of the stud. Platinum is deposited preferably via sputter deposition, conformally coating all regions of the structure. After sintering, the unreacted platinum is removed using wet chemical etch (aqua regia). Platinum silicide is left in all opened contacts and on the stud sidewalls where its defines a metal silicide lining (25) or cap, covering the stud. This lining connects the top surface (25a) of the stud, with the channel stop implanted regions (18) and then forms the desired substrate contact.

Method of selectively exposing the sidewalls of a trench and its use to

The present method discloses the steps to form metal device contact studs between regions of a semiconductor device, such as an NPN vertical bipolar transistor, and the first level metal, the studs overlapping both a contact region (such as the base or the collector) and an adjacent polyimide-filled trench. The method is comprised of the following steps:

Method for making metal contact studs between first level metal and

A process for etching deep trenches to achieve dielectric isolation for integrated circuit devices; the process insures obtaining substantially perfectly vertical trench walls by precluding significant variation in etch bias during the trench formation.

Trench etch process for dielectric isolation

A differential reactive ion etching process significantly reduces the reflectivity of silicon. The process takes place in a reactive ion etching tool, typically a diode-configured system employing ambient gases which react with the silicon.

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Poughkeepsie, NY, United States of America

Thomas A Hansen