Method of making substractive rim phase shifting masks

A method for forming a rim phase shifting mask for semiconductor manufacture comprising:

• forming an opaque layer having a thickness of "t" on a transparent substrate;
• depositing and patterning a layer of photoresist on the opaque layer and etching openings through the opaque layer to the substrate to form a pattern of opaque light blockers having sidewalls;
• removing the photoresist;
• etching the substrate aligned with the openings to a depth of "d";
• forming phase shifters on the sidewalls of the opaque light blockers and light transmission openings in the openings by conformally depositing a transparent phase shift material over the opaque layer and openings to a thickness of "P";
• said phase shift material not being etched and remaining in said light transmission openings and on the sidewalls to a thickness of "P";
• and
• selecting "t" and "d" to form the rim phase shifters so that light passing through the rim phase shifters travels a distance through the phase shift material of "t"+"d"+"P" and is phase shifted relative to light passing through the light transmission openings which travels a distance through the phase shift material of "P".

A method for forming a rim phase shifting mask for semiconductor manufacture comprising:

• providing a mask blank comprising a transparent substrate with an opaque layer having a thickness of "t";
• depositing and patterning a layer of photoresist on the opaque layer and etching openings through the opaque layer to the substrate to form a pattern of opaque light blockers having sidewalls;
• etching the substrate in alignment with the openings to a depth of "d";
• removing the photoresist;
• forming phase shifters on the sidewalls of the opaque light blockers and light transmission openings in the openings by conformally depositing a transparent phase shift layer over the opaque layer and onto the etched substrate to a thickness of "P";
• said rim phase shifters self aligned with the sidewalls and having a width of "P" and a thickness measured from a surface of the etched substrate to a surface of the phase shift layer of "t"+"d"+"P";
• and
• said phase shift layer not being etched and remaining in said light transmission openings to achieve a phase shift for light passing through a rim phase shifter relative to light passing through a light transmission opening.