METHOD FOR FORMING TUNGSTEN CONTACT HAVING LOW RESISTANCE AND LOW DEFECT DENSITY FOR SILICON SEMICONDUCTOR WAFER

摘要

PURPOSE: To prevent generation of defective particles and to prevent formation of titanium silicide along the wall of a contact opening by forming an electric contact between tungsten and a silicon wafer through a silicide, thereby coupling tungsten with titanium nitride. CONSTITUTION: A Ti layer is formed on the surface of side wall of a contact opening 24 penetrating an insulator from the surface thereof and a silicon substrate exposed on the bottom thereof. The silicon where Ti is exposed and the surface of Ti coating are then annealed in an atmosphere containing nitrogen and a double layer of titanium nitride 34 and low resistance titanium silicide 32 is formed on the silicon substrate followed by deposition of titanium silicide on the surface of the insulation layer. On the other hand, the surface of Ti coating is exposed to oxygen. Remaining part of the contact opening is filled with tungsten adhering to the double layer. This structure realizes a good electric contact on a silicon substrate.