Method of forming pattern for semiconductor device

A method, comprising:

• providing a substrate having a first layer and a hard mask layer formed on the first layer;
• etching a first pattern in the hard mask layer, wherein the first pattern includes a plurality of elements having a first width;
• after etching the first pattern, performing a second etching process on the hard mask layer, wherein the second etching process modifies the first pattern to provide a second pattern having a plurality of elements of a second width, the second width being less than the first width;
• forming a conformal layer on the second pattern formed in the hard mask layer;
• etching the conformal layer to form a spacer element a sidewall of each of the plurality of elements having the second width;
• and
• using the spacer elements and the plurality elements having the second width as masking elements while etching the first layer.

A method of semiconductor fabrication, comprising:

• providing a substrate;
• performing a first photolithography process, a first etch process, a second photolithography process and a second etching process to form a plurality of features in a first layer disposed on the substrate;
• form a sidewall spacer element on each of the plurality of features;
• and
• using the plurality of features and the sidewall spacer elements as a masking element during an anisotropic etching process of an underlying layer.