Method for shrinking critical dimension of semiconductor devices

A method for fabricating a semiconductor device having a shrunk critical dimension, comprising the steps of:

• forming a first pattern of a chemical amplification (CA) type photoresist layer on a semiconductor device layer, wherein the CA type photoresist layer has been developed and exposes portions of the underlying semiconductor device layer;
• performing a blanket exposing process to expose the CA type photoresist layer and the exposed semiconductor device layer thereof to light having a wavelength capable of being absorbed by the CA type photoresist layer to provide the CA type photoresist layer with a predetermined energy per unit area, thereby producing photo generated acids therein;
• executing a first thermal process to diffuse the photo generated acids formed within the CA type photoresist layer and to equalize glass transition temperature (Tg) of the CA type photoresist layer;
• coating a polymer layer over the CA type photoresist layer, wherein the polymer layer is capable of forming a cross-linked film in portions of the polymer layer, which are in contact with the CA type photoresist layer;
• and
• thereafter executing a second thermal process, wherein the first thermal process is carried out under a temperature lower than the glass transition temperature (Tg) of the CA type photoresist layer.