Manufacturable process for tungsten polycide contacts using amorphous silicon
AssigneeVanguard International Semiconductor Corporation
InventorsHaw Yen, Shaw-Tseng Hsia
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Abstract
A method for creating manufacturable polycide contacts, for use in advanced semiconductor designs using images as small as 0.35 .mu.M, has been developed. An amorphous silicon film, is used as an underlay, to assist in the growth of an overlying tungsten silicide layer. The tungsten silicide deposition is performed using tungsten hexafluoride and silane, and in conjunction with the amorphous silicon underlay, results excellent step coverage in the narrow contact hole. A nitrogen anneal, using high flow rates, optimizes the adhesion characteristics of the tungsten polycide structure.
Claims22
A method for fabricating a MOSFET device on a semiconductor substrate, using a polycide coated hole to provide electrical contact between active device regions in the substrate, and the interconnect metallizations, comprising the steps of:
- providing the active device elements in said semiconductor substrate;
- depositing a first dielectric layer on said semiconductor substrate, that includes said active device elements;
- photolithe, graphic processing to open a region in photoresist, exposing said first dielectric layer, directly overlying said active device element;
- anisotropic removal of said first dielectric layer, in said opened region of photoresist, to create a contact hole to said active device element;
- surface cleaning of said active device element, in said contact hole opening;
- depositing a layer of amorphous silicon on said active device element, in said contact hole opening, and on the surface of said first dielectric layer;
- ion implanting a first conductivity imparting dopant into said silicon layer;
- surface cleaning of said silicon layer;
- depositing a metal silicide layer on said silicon layer, to form a metal polycide;
- patterning of said metal polycide to form contact structure;
- and
- annealing of said metal polycide contact structure.
A method for fabricating a MOSFET device or, a semiconductor substrate, using a tungsten polycide coated contact hole to provide electrical contact between source and drain regions in the substrate, and interconnect metallizations, comprising the steps of:
- providing source and drain regions in said semiconductor substrate;
- depositing a first dielectric layer on said semiconductor substrate, that includes exposed said source and drain regions;
- photolithographic processing to open a region in photoresist, exposing said first dielectric layer, directly overlying said source and drain region;
- anisotropic removal of said first dielectric layer, in said opened region of photoresist, to create a contact hole to said source and drain region;
- surface cleaning of said source and drain region, in said contact hole opening;
- depositing a layer of amorphous silicon on said source and drain region, in said contact hole opening, and on surface of said first dielectric layer;
- ion implanting a first conductivity imparting dopant into said amorphous silicon layer;
- surface cleaning of said amorphous silicon layer;
- depositing a tungsten silicide layer on said amorphous silicon layer, to form tungsten polycide;
- patterning of said tungsten polycide to form contact structure;
- and
- annealing of said tungsten polycide contact structure.
Dependencies are inferred from the claim text.