Pattern formation method using a photo mask for manufacturing a semiconductor device

A method of manufacturing a photo mask, the method comprising:

• receiving original mask layout data;
• finding, by using a computer, two patterns aligned in a first direction and spaced apart from each other by a gap which is sandwiched by other two patterns arranged in parallel with the two patterns in a second direction crossing the first direction;
• when a distance of the gap is equal to or greater than a first threshold distance and less than a second threshold distance smaller than the first threshold distance, inserting, by using the computer, a sub-resolution pattern extending in the first direction and connecting the two patterns, a width of the sub-resolution pattern is smaller than a resolution limit of an optical lithography tool, with which the photo mask is used;
• generating, by using the computer, new mask layout data including the sub-resolution pattern;
• and
• manufacturing the photo mask according to the new mask layout data.

A photo mask for manufacturing a semiconductor device, the photo mask comprising:

• a first pattern extending in a first direction;
• a second pattern extending in the first direction and aligned with the first pattern;
• and
• a sub-resolution pattern extending in the first direction, disposed between an end of the first pattern and an end of the second pattern, wherein:
• a width of the first pattern and a width of the second pattern are equal to each other, and
• the first pattern and the second pattern are for separate circuit elements in the semiconductor device.