Method of fabricating an opening with deep ultra-violet photoresist

A method of fabricating an opening wherein a substrate having a device structure and a metal layer formed thereon is provided, comprising separate steps as follows:

• forming a dielectric layer over the substrate;
• forming a deep ultra-violet photoresist layer with a first opening on the dielectric layer wherein the deep ultra-violet photoresist layer has a surface and sidewalls;
• forming a hard mask layer by silylation on the surface and the sidewalls of the deep ultra-violet photoresist layer in a plasma treatment step;
• forming a via hole by etching the dielectric layer using the first opening of the deep ultra-violet photoresist layer to expose the metal layer;
• and
• removing the deep ultra-violet photoresist layer and the hard mask layer to expose the dielectric layer,
• wherein as the said step of etching the dielectric layer is performed, a portion of the hard mask layer is removed from the surface of the deep ultra-violet photoresist and a portion of the hard mask layer is left on the sidewalls of the deep ultra-violet photoresist layer.

A method of fabricating an opening wherein a substrate having a device structure and a doped region formed thereon is provided, comprising separate steps as follows:

• forming an insulating layer over the substrate;
• forming a deep ultra-violet photoresist layer with a first opening on the insulating layer wherein the deep ultra-violet photoresist layer has a surface and sidewalls;
• forming a hard mask layer by silylation on the surface and the sidewalls of the deep ultra-violet photoresist layer in a plasma treatment step;
• forming a contact hole by etching the insulating layer using the first opening of the deep ultra-violet photoresist layer to expose the doped region;
• and
• removing the deep ultra-violet photoresist layer and the hard mask layer to expose the insulating layer,
• wherein as the said step of etching the insulating layer is performed, a portion of the hard mask layer is removed from the surface of the deep ultra-violet photoresist and a portion of the hard mask layer is left on the sidewalls of the deep ultra-violet photoresist layer.