The present invention discloses a method for forming a fine pattern of a semiconductor device comprising: forming a first photoresist pattern over a semiconductor substrate including an underlying layer. A cross-linking layer is formed on the sidewall of the first photoresist pattern. The first photoresist pattern is removed to form a fine pattern including a silicon polymer. A second photoresist pattern is formed that is coupled to the fine pattern. The underlying layer is etched using the fine pattern and the second photoresist pattern as an etching mask. As a result, the fine pattern has a smaller size than a minimum pitch.