Methods of patterning photoresist
Methods of patterning photoresist are disclosed. One example method includes forming photoresist on a substrate having a lower layer; performing a first exposure process to the photoresist in state of positioning a mask on the photoresist; performing a first development process to the photoresist; performing a second entire-surface exposure process to the photoresist; and performing a second development process to the photoresist.
1 . A method of patterning a photoresist pattern comprising:
forming a photoresist on a substrate having a lower layer;
performing a first exposure process to the photoresist in state of positioning a mask on the photoresist;
performing a first development process to the photoresist;
performing a second entire-surface exposure process to the photoresist; and
performing a second development process to the photoresist.
2 . The method of claim 1 , further comprising, performing an oxygen plasma treatment to the lower layer, before forming the photoresist.
3 . The method of claim 1 , further comprising, performing a soft-baking process to the photoresist, to remove a solvent from the photoresist, before performing the first exposure process.
4 . The method of claim 1 , wherein the soft-baking process is performed at a temperature level not to pyrolyze components of the photoresist.
5 . The method of claim 1 , further comprising, baking the exposed photoresist, before performing the first development process.
6 . The method of claim 1 , wherein the lower layer is formed of a silicon nitride layer or a silicon oxide layer.
7 . The method of claim 1 , wherein an exposure-energy level of the exposure process is appropriate for decreasing a thickness of the photoresist at 5% to 20%.
8 . The method of claim 1 , wherein the first and second exposure processes use the same light source.
9 . The method of claim 1 , wherein the first and second exposure processes use the light source of g-line of 436 nm, i-line of 365 nm, h-line of 405 nm, and a broad band of 240 nm to 440 nm, emitted from a mercury or xenon Xe lamp.
10 . The method of claim 1 , wherein the first and second exposure processes use the light source of KrF laser having a wavelength of 248 nm corresponding to a DUV (Deep Ultraviolet) region and ArF laser having a wavelength of 193 nm.
11 . The method of claim 1 , wherein the second exposure process is performed with the same mask used during the first exposure process.