Method of forming a semiconductor device

A method of forming a semiconductor device, comprising:

• forming a first mask pattern on a target layer, the first mask pattern exposing a first portion of the target layer;
• forming an intermediate material pattern;
• forming a second mask pattern that exposes portions of the intermediate material pattern;
• removing the exposed portions of the intermediate material pattern to expose a second portion of the target layer;
• and
• patterning the target layer using the first and second mask patterns as patterning masks;
• and
• wherein forming the intermediate material pattern includes:
• depositing an intermediate material on a side of the first mask pattern and the first portion of the target layer, and
• thinning the intermediate material to form the intermediate material pattern, and
• forming the intermediate material pattern is repeated more than one cycle.