Method of fabricating phase shift mask and method of fabricating semiconductor device
A method for fabricating a phase shift mask includes preparing a transmissive substrate on which a first mask region and a second mask region surrounding the first mask region are defined. In the first mask region, main patterns are formed having a first pitch in a first direction and a second direction perpendicular to the first direction. Each of the main patterns has a first area. In at least one row, assist patterns are formed at the first pitch to surround the main patterns. Each of the assist patterns has a second area less than the first area. In the second mask region, dummy patterns are formed in a plurality of rows. The dummy patterns surround the assist patterns at the first pitch. Each of the dummy patterns has a third area greater than the first area.
1. A method for fabricating a semiconductor device, the method comprising:
forming a material layer on a semiconductor substrate on which a cell region and an outer region surrounding the cell region are defined;
sequentially forming a mold layer and a support forming layer on the material layer;
forming a plurality of holes exposing the material layer by etching the mold layer and the support forming layer;
forming a plurality of lower electrodes by applying a conductive material onto an inner wall of the plurality of holes; and
etching the support forming layer to form a plurality of open regions and forming a support connecting the plurality of lower electrodes using a photolithography process using a phase shift mask, wherein the phase shift mask includes:
a transmissive substrate,
main patterns on the transmissive substrate, the main patterns arranged at a first pitch, each of the main patterns having a first area,
assist patterns on the transmissive substrate, the assist patterns surrounding the main patterns and arranged at the first pitch, each of the assist patterns having a second area less than the first area, and
dummy patterns on the transmissive substrate, the dummy patterns surrounding the assist patterns and arranged at the first pitch, each of the dummy patterns having a third area greater than the first area.
2. The method as claimed in claim 1 , wherein forming the lower electrodes includes forming the lower electrodes arranged in a plurality of hexagon structures, wherein
each hexagon structure includes at least six lower electrodes at vertices of each hexagon structure.
3. The method as claimed in claim 1 , wherein forming the support includes forming the open regions at positions corresponding to the main patterns.
4. The method as claimed in claim 1 , wherein forming the support includes forming the support in a planar shape having four edges, and wherein two edges of the four edges face each other in a first direction and are straight lines.
5. The method as claimed in claim 4 , wherein the lower electrodes are asymmetrically formed in a periphery of the two edges facing each other in the first direction.
6. The method of claim 1 , wherein forming the support includes forming the support in a planar shape having four edges, and wherein two edges of the four edges face each other in a second direction and are waveforms.
7. The method as claimed in claim 6 , wherein a radius of curvature of each of the waveforms is greater than a radius of curvature of each of the open regions.
8. The method as claimed in claim 1 , wherein forming the support includes entirely etching a portion of the support forming layer, corresponding to the dummy patterns and formed in the outer region of the semiconductor substrate.