Process for creating high density integrated circuits utilizing double coating photoresist mask

A method of forming a double coating photoresist mask to allow line widths narrower than the photolithography resolution limit in the fabrication of an integrated circuit comprising:

• coating a semiconductor substrate with a first layer of photoresist;
• exposing said first photoresist layer to light through a mask, developing said first photoresist layer and removing parts of said first photoresist layer to produce a first patterned photoresist layer having first openings wider than said resolution limit, said first openings free of said first photoresist layer;
• hardening said first patterned photoresist layer;
• coating said semiconductor substrate with a second photoresist layer so that said second photoresist layer is within said first openings in said first patterned photoresist layer;
• exposing said second photoresist layer to light through a mask, developing said second photoresist layer and removing parts of said second photoresist layer to produce a second pattern from said second photoresist layer wherein said second pattern lies within said first openings in said first patterned photoresist layer so that regions of said first patterned photoresist layer are interleaved with regions of said second pattern laterally across at least a portion of said semiconductor substrate, leaving portions of said semiconductor substrate not covered with photoresist between adjacent regions of said first patterned photoresist layer and said second pattern.

A method of forming a double coating photoresist mask to allow for line spacing narrower than the photolithography resolution limit in the fabrication of an integrated circuit comprising:

• providing at least one layer to be etched overlying a semiconductor substrate;
• coating said layer to be etched with a first layer of photoresist;
• exposing said first photoresist layer to light through a mask, developing said first photoresist layer and removing parts of said first photoresist layer to produce a first patterned photoresist layer having first openings wider than said resolution limit as measured along a first direction, said first openings free of photoresist from said first photoresist layer;
• hardening said first patterned photoresist layer;
• coating said layer to be etched with a second photoresist layer so that said second photoresist layer is within said first openings in said first patterned photoresist layer;
• and
• exposing said second photoresist layer to light through a mask, developing said second photoresist layer and removing parts of said second photoresist layer to produce a second pattern from said second photoresist layer which lies within said first openings in said first patterned photoresist layer so that regions of said first patterned photoresist layer are interleaved with regions of said second pattern laterally along said first direction across at least a portion of said layer to be etched, leaving said layer to be etched not covered with photoresist between adjacent regions of said first patterned photoresist layer and said second pattern.