Patent attributes
A photo mask which is used for exposure of an isolated pattern and a dense pattern for a semiconductor substrate. The photo mask includes a transparent substrate, a pair of first patterns, a first assistant pattern and a plurality of second patterns. The pair of first patterns is separated from each other by a first distance, wherein one of the first pattern is arranged at one side of the isolated pattern, and another of the first pattern is arranged at another side. The first assistant pattern is provided apart from the one of the first pattern by the first distance. In the plurality of second patterns, each of the linear patterns is sandwiched between two of the second patterns that are adjacent to each other. One of the linear patterns is separated from adjacent the other of the linear patterns by a predetermined distance. A phase of light transmitted through the one of the first pattern and a phase of light transmitted through the assistant pattern are opposite to each other. A phase of light transmitted through one of the second patterns and a phase of light transmitted through another of the second patterns adjacent to the one of the second pattern are opposite to each other.
