Silicide protection during contact metallization and resulting semiconductor structures

摘要

A semiconductor transistor has a structure including a semiconductor substrate, a source region, a drain region and a channel region in between the source region and the drain region. A metal gate, having a top conductive portion of tungsten is provided above the channel region. A first silicon nitride protective layer over the source region and the drain region and a second silicon nitride protective layer over the gate region are provided. The first silicon nitride protective layer and the second silicon nitride protective layer are configured to allow punch-through of the first silicon nitride protective layer while preventing etching through the second silicon nitride protective layer. Source and drain silicide is protected by avoiding fully etching a gate opening unless either the etching used would not harm the silicide, or the silicide and source and drain contacts are created prior to fully etching an opening to the gate for a gate contact.

主权项

1. A method, comprising:
providing a semiconductor structure for a transistor, the structure comprising a metal gate coupled to a channel region and a spacer of protective material on either side of the metal gate; creating a first layer of protective material over a source region and a drain region of the transistor; creating a second layer of protective material over the gate; wherein the first protective layer acts as an etch stop for creating intermediate openings to the source region and the drain region, and wherein the first and second protective layers are configured to allow punch-through of the first protective layer while preventing etching through the second protective layer; and creating silicide in the source region and the drain region after creating an intermediate gate opening and prior to fully etching a gate opening.