Method of forming a mask pattern
A method of forming a mask pattern and, more particularly, a method of forming a mask pattern wherein micro patterns having resolutions lower than those of exposure equipment by overcoming the resolutions of the exposure equipment, wherein, a silicon layer is formed over a substrate and is patterned. The patterned silicon layer is oxidized to form the entire surface of the silicon layer to a specific thickness by using an oxide layer. The oxide layer is removed to expose a top surface of the silicon layer. A mask pattern is formed with the remaining oxide layer by removing the silicon layer.
1. A method of forming a mask pattern, comprising:
forming a silicon layer over a substrate;
patterning the silicon layer to form silicon layer patterns having an exposed surface;
oxidizing the exposed surface of the silicon layer patterns by a thermal oxidization process, thereby forming oxide layers to cover each silicon layer pattern, wherein the oxide layers are isolated from each other;
removing the oxide layers formed over a top surface of the silicon layer patterns, leaving the sidewalls still covered with the oxide layers; and
removing the silicon layer patterns to form mask patterns with the remaining oxide layers.
2. The method of claim 1 , wherein the oxide layer has a half pitch of 20 nm to 50 nm.
3. The method of claim 1 , wherein the mask pattern has a width narrower than that of the patterned silicon layer.
4. The method of claim 1 , comprising patterning the silicon layer in exposure equipment having resolutions of 50 nm to 200 nm.
5. The method of claim 1 , comprising forming the silicon layer from amorphous silicon or polysilicon.
6. The method of claim 1 , comprising patterning the silicon layer to the extent that a distance between the oxide layers becomes a target distance by taking into consideration that the distance between the oxide layers is narrowed as the oxide layers grow.
7. The method of claim 1 , comprising forming the oxide layers by the thermal oxidization process at a temperature of 650° C. to 750° C.