Method of processing a substrate

A method of processing a substrate, comprising:

• forming a photosensitive layer on the substrate;
• performing a first exposure process to expose the photosensitive layer to actinic radiation through a first mask, wherein the first mask has a plurality of first opaque portions;
• performing a first developing process to remove portions of the photosensitive layer exposed to the actinic radiation and form an intermediate pattern;
• performing a second exposure process to expose the intermediate pattern to the actinic radiation through a second mask, wherein the second mask has a plurality of second opaque portions;
• performing a second developing process to remove portions of the intermediate pattern shielded from the actinic radiation and form a target pattern;
• and
• performing an etching process to remove portions of the substrate exposed through the target pattern;
• wherein during the second exposure process, an alignment of the second mask is set at a position that centers of the plurality of second opaque portions of the second mask are aligned with centers of the plurality of first opaque portions.