Optical proximity correction method and method of fabricating lithography mask by using the same

An optical proximity correction (OPC) method comprising:

• providing a design layout including conductive patterns;
• determining line end void (LEV)-risk patterns among the conductive patterns, the LEV-risk patterns each having a risk of suffering from poor contact due to an LEV;
• setting markers including portions of the LEV-risk patterns and portions of the conductive patterns adjacent to the LEV-risk patterns;
• performing a first OPC on first patterns included in the markers and performing a second OPC on second patterns outside the markers, the second OPC being different from the first OPC, and each of the first OPC and the second OPC being performed a plurality of times;
• and
• calculating a cost function of each of the markers using information associated
• with a corresponding one of the LEV-risk patterns and a process window condition, wherein
• the determining includes comparing risks of occurrence of poor contact in each of the conductive patterns based on a scoring function, and
• the scoring function is inversely proportional to a width of each of the conductive patterns.

A method of fabricating a lithography mask, the method comprising:

• providing a design layout including conductive patterns;
• performing optical proximity correction (OPC) on the design layout;
• and
• fabricating the lithography mask according to a result of the performing,
• wherein the performing includes,
• determining line end void (LEV)-risk patterns among the conductive patterns, the LEV-risk patterns each having a risk of suffering from poor contact due to an LEV, setting markers including portions of the LEV-risk patterns and portions of the conductive patterns adjacent to the LEV-risk patterns,
• performing first OPC on patterns inside the markers and performing second OPC on patterns outside the markers, the second OPC being different from the first OPC, and
• calculating each of a plurality of cost functions of each of the markers by using an LEV-aware OPC best contour and a process window condition (PWC) contour, the LEV-aware OPC best contour being a first contour according to an optimum condition for each of the LEV-risk patterns that has been modified by the first OPC, and the PWC contour being a second contour according to a PWC for each of the LEV-risk patterns that has been modified by the first OPC.