Pre-silicide spacer removal
View Patent ↗A method forms a gate conductor over a substrate, and simultaneously forms spacers on sides of the gate conductor and a gate cap on the top of the gate conductor. Isolation regions are formed in the substrate and the method implants an impurity into exposed regions of the substrate not protected by the gate conductor and the spacers to form source and drain regions. The method deposits a mask over the gate conductor, the spacers, and the source and drain regions. The mask is recessed to a level below a top of the gate conductor but above the source and drain regions, such that the spacers are exposed and the source and drain regions are protected by the mask. With the mask in place, the method then safely removes the spacers and the gate cap, without damaging the source/drain regions or the isolation regions (which are protected by the mask). Next, the method removes the mask and then forms silicide regions on the gate conductor and the source and drain regions.
1. A method of forming an integrated circuit transistor, said method comprising:
forming a gate conductor over a substrate;
simultaneously forming spacers on sides of said gate conductor and a gate cap on top of said gate conductor;
implanting an impurity into exposed regions of said substrate not protected by said gate conductor and said spacers to form source and drain regions;
depositing a mask over said gate conductor, said spacers, and said source and drain regions;
recessing said mask to a level below a top of said gate conductor and above said source and drain regions such that said gate cap and a portion of said spacers are exposed and said source and drain regions are protected by said mask;
removing said spacers and said gate cap;
removing said mask; and
forming silicide regions on said gate conductor and said source and drain regions.
2. The method according to claim 1 , wherein said removing of said spacers simultaneously removes said gate cap.
3. The method according to claim 1 , further comprising forming isolation regions in said substrate adjacent said source and drain regions, wherein said mask protects said isolation regions during said removing of said spacers.
4. A method of forming an integrated circuit transistor, said method comprising:
forming a gate conductor over a substrate;
simultaneously forming nitride spacers on sides of said gate conductor and a gate cap on top of said gate conductor;
implanting an impurity into exposed regions of said substrate not protected by said gate conductor and said nitride spacers to form source and drain regions;
depositing a mask over said gate conductor, said nitride spacers, and said source and drain regions;
recessing said mask to a level below a top of said gate conductor and above said source and drain regions such that said gate cap and a portion of said nitride spacers are exposed and said source and drain regions are protected by said mask;
removing said nitride spacers;
removing said mask and said gate cap; and
forming silicide regions on said gate conductor and said source and drain regions.
5. The method according to claim 4 , wherein said removing of said nitride spacers simultaneously removes said nitride gate cap.
6. The method according to claim 4 , further comprising forming isolation regions in said substrate adjacent said source and drain regions, wherein said mask protects said isolation regions during said removing of said nitride spacers.