Phase shift mask and fabricating method thereof
View Patent ↗The present invention provides a phase shift mask and fabricating method thereof, by which a critical dimension of a semiconductor pattern can be accurately formed in a manner of compensating a boundary step difference between an active area and an insulating layer. The present invention includes a transparent substrate and at least two halftone layers on the transparent substrate to have light transmittance lower than that of the transparent substrate, each comprising front and rear parts differing in thickness from each other.
1. A method of fabricating a phase shift mask, comprising the steps of:
forming a halftone layer on a transparent substrate;
forming a first photoresist pattern on the halftone layer to define at least two areas;
patterning the halftone layer using the first photoresist pattern so as to create a first halftone layer portion and a second halftone layer portion;
removing the first photoresist pattern;
forming a second photoresist pattern covering the first halftone layer portion, but not the second halftone layer portion on the transparent substrate;
etching the second halftone layer portion and an exposed surface of the transparent substrate to a first thickness and a second thickness, respectively; and
removing the second photoresist pattern,
wherein the step of forming a second photoresist pattern includes forming a pair of inclined portions that cover respective sidewalls of the first halftone layer portion, said inclined portions having predetermined slopes.
2. The method of claim 1 , wherein said predetermined slopes having a common slope angle, but different direction.
3. The method of claim 2 , wherein an etched surface of the transparent substrate has a recessed incline having a same slope angle as the common slope angle.
4. The method of claim 1 , the halftone layer forming step comprising the steps of: forming a phase shift layer on the transparent substrate; and forming a shield layer on the phase shift layer.
5. The method of claim 4 , wherein the phase shift layer and the shield layer are formed on MoSiN and Cr, respectively.
6. A method of fabricating a phase shift mask, comprising steps for:
forming a halftone layer on a transparent substrate;
forming a first photoresist pattern on the halftone layer to define at least two areas;
patterning the halftone layer using the first photoresist pattern so as to create a first halftone layer portion and a second halftone layer portion;
removing the first photoresist pattern;
forming a second photoresist pattern covering the first halftone layer portion, but not the second halftone layer portion on the transparent substrate;
etching the second halftone layer portion and an exposed surface of the transparent substrate to a first thickness and a second thickness, respectively; and
removing the second photoresist pattern,
wherein the step for forming a second photoresist pattern includes forming a pair of inclined portions that cover respective sidewalls of the first halftone layer portion, said inclined portions having predetermined slopes.