MOST contact structure, especially a gate contact structure, is produced using an etch-stop layer to protect the gate and adjacent side wall spacer during contact opening etching

摘要

MOST contact structure production, comprising use of an etch-stop layer to protect the gate and adjacent side wall spacer during etching of a contact opening, is new. A contact structure is formed on a MOST by: (a) successively forming an etch-stop layer (330), a dielectric layer (332) and a mask on the transistor; (b) exposing one or more dielectric layer surface regions by patterning the mask which defines a first contact region on the etch-stop layer surface and a second contact region on the surface of the transistor gate (324) above the channel region (320); (c) etching the exposed dielectric layer down to the first contact region of the etch-stop layer surface; and (d) etching the exposed etch-stop layer down to the second contact region to form a contact opening. An Independent claim is also included for a MOS contact structure produced by the above process. Preferred Features: The gate consists of polysilicon with an overlying silicon metal layer, the etch-stop layer consists of silicon oxy nitride and the dielectric layer consists of silicon dioxide.