Metal-containing liner process

A method of processing a substrate, the method comprising:

• depositing a first sidewall spacer layer over the substrate, the substrate comprising a layer stack comprising alternating layers of a nanosheet and a sacrificial layer, and a dummy gate disposed over the layer stack;
• anisotropically etching the first sidewall spacer layer to remove a horizontal portion of the first sidewall spacer layer and to form a dummy gate spacer;
• depositing a metal-containing liner over the substrate, the metal-containing liner covering the dummy gate spacer;
• anisotropically etching the metal-containing liner to remove a horizontal portion of the metal-containing liner;
• performing an anisotropic source/drain fin etch back to form vertical recesses in the layer stack;
• isotropically etching the layer stack to selectively remove a part of the sacrificial layer and form indentations between adjacent ones of the nanosheets;
• depositing a second sidewall spacer layer to fill the indentations;
• and
• etching a portion of the second sidewall spacer layer to expose tips of the nanosheets, a remaining portion of the second sidewall spacer layer forming a second sidewall spacer.

A method of processing a substrate, the method comprising:

• depositing a first sidewall spacer layer over the substrate, the substrate comprising a layer stack comprising alternating layers of a nanosheet and a sacrificial layer, and a dummy gate disposed over the layer stack;
• depositing a metal-containing liner over the first sidewall spacer layer, the metal-containing liner having a thickness less than a thickness of the first sidewall spacer layer;
• anisotropically etching the metal-containing liner and the first sidewall spacer layer;
• performing an anisotropic source/drain fin etch back process to form vertical recesses;
• after performing the anisotropic source/drain fin etch back, performing a wet etch cleaning;
• laterally etching to selectively remove a part of the sacrificial layer and form indentations between the nanosheets;
• depositing a second sidewall spacer layer to fill at least a portion of the indentations;
• and
• etching a portion of the second sidewall spacer layer to expose tips of the nanosheets.