Method for forming semiconductor device

A manufacturing method for forming a semiconductor device, at least comprising the following steps:

• providing a substrate, a fin structure is formed on the substrate, and a plurality of gate structures are formed on the fin structure;
• forming an interlayer dielectric on the gate structures;
• forming a hard mask layer and a first photoresist layer on the interlayer dielectric;
• performing a first etching process on the first photoresist layer, to form at least one first trench in the first photoresist layer and in the hard mask layer, so as to define a region;
• forming a plurality of patterned photoresist layers on the remaining hard mask layer, wherein each patterned photoresist layer is disposed right above each gate structure, and the width of each patterned photoresist is larger than the width of each gate structure;
• and
• using the remaining hard mask layer and the patterned photoresist layer as a hard mask to perform an second etching process to form a plurality of second trenches, wherein the second trenches are only disposed within the region, and each second trench at least partially overlaps the range of the first trench.