Manufacturing capping layer for the fabrication of cobalt salicide structures

A process for forming a cobalt disilicide layer on exposed silicon regions of a silicon substrate comprising the steps of:

• providing a silicon substrate having exposed and unexposed silicon regions;
• depositing on said silicon substrate a first layer comprising a metallic cobalt material;
• depositing on said cobalt layer a second layer comprising a titanium nitride material;
• depositing on said titanium nitride layer a third layer comprising a metallic titanium material;
• performing a plurality of annealling steps to form a cobalt disilicide layer disposed above said exposed silicon regions.

A method for forming a polycrystalline cobalt disilicide structure on a metal oxide transistor in a silicon substrate, comprising the steps of:

• providing a silicon substrate having a transistor formed thereon, said transistor having gate, source, and drain regions, said gate having a length dimension of about 0.20 .mu.m or less;
• depositing a layer of cobalt on said substrate;
• thereafter depositing a layer of titanium nitride on said cobalt layer;
• thereafter depositing a layer of titanium on said titanium nitride layer;
• thereafter heating said substrate to form a polycrystalline cobalt disilicide layer on said source, gate, and drain regions of said transistor, said heating step comprising a first heating step and a second heating step, said second heating step being performed at a higher temperature than said first heating step;
• and
• selectively etching, in between said first and second heating steps, to strip the remaining nonsilicide cobalt, titanium, and titanium nitride material from said substrate except in said gate, source, and drain regions.

A process for forming cobalt disilicide contacts on a semiconductor device comprising the steps of:

• providing a semiconductor substrate, said substrate having a microcircuit structure with silicon contact areas formed thereon;
• depositing a metallic cobalt layer onto said silicon substrate;
• depositing a titanium nitride layer onto said cobalt layer;
• depositing a metallic titanium layer onto said titanium nitride layer;
• performing a first anneal of said substrate whereby the contact areas and some of said cobalt layer react to form a cobalt monosilicide layer disposed above said contact areas;
• stripping said layers of metallic cobalt material, titanium nitride material, and metallic titanium material, leaving said cobalt monosilicide disposed above said contact areas;
• and
• performing a second anneal of said substrate whereby said cobalt monosilicide layer undergoes further reaction to form cobalt disilicide contacts disposed above said contact areas.

A process for forming fill structures leading to cobalt disilicide contacts, comprising the steps of:

• providing a semiconductor substrate having contact regions;
• depositing on said silicon substrate a first layer comprising a metallic cobalt material;
• depositing on said cobalt layer a second layer comprising a titanium nitride material;
• depositing on said titanium nitride layer a third layer comprising a metallic titanium material;
• performing a first anneal of said substrate, said first annealling forming cobalt monosilicide regions disposed above said contact regions;
• stripping said layers of unreacted metallic cobalt material, titanium nitride material, and metallic titanium material, leaving the cobalt monosilicide regions in place;
• performing a second anneal of said substrate whereby said cobalt monosilicide undergoes further reaction to form cobalt disilicide contacts disposed above said contact regions;
• forming a passivation layer over said substrate, said passivation layer having vias disposed above said cobalt disilicide contacts;
• and
• filling said vias with a conducting fill material.