Method of forming patterns
View Patent ↗In forming a mask pattern on a circuit board, a mask pattern of N-layer structure is formed in a region where the mechanical strength of the circuit board needs to be increased. N photosensitive layers are first stacked on a substrate so that they becomes lower in sensitivity from the first photosensitive layer toward the N th photosensitive layer. In the first photosensitive layer (bottom layer), a first pattern is formed and has the same shape as a predetermined pattern to be formed on the circuit board. In the K th photosensitive layer (N≧K≧2), a K th pattern is formed so that the K th pattern is smaller than a (K−1) st pattern formed in the (K−1) st photosensitive layer and arranged inside the (K−1) st pattern.
1. A method of forming an N-layer mask pattern in N photosensitive layers (N≧2) formed on a substrate by exposure and development, comprising the steps of:
stacking said N photosensitive layers on said substrate so that they becomes lower in sensitivity from the first photosensitive layer which is the bottom layer of said N photosensitive layers, toward the N th photosensitive layer;
forming a first pattern of the same shape as a predetermined pattern to be formed on said substrate, in said first photosensitive layer;
forming a K th pattern in the K th photosensitive layer (N≧K≧2) so that said K th pattern is smaller than a (K−1) st pattern formed in the (K−1) st photosensitive layer and arranged inside said (K−1) st pattern; and
forming said N-layer mask pattern comprising said N photosensitive layers in which said first to N th patterns are formed.
2. The method as set forth in claim 1 , wherein said exposure is performed by employing an exposure system that exposes a surface by imaging a light beam modulated based on a value of each pixel data constituting binary image data, onto said surface.
3. The method as set forth in claim 2 , wherein said exposure is performed so that light energy irradiated is increased in stages from an edge of said first pattern toward the center of said N th pattern.
4. The method as set forth in claim 1 , wherein said N th pattern is formed so that a distance (t 2 ) from an edge of said N th pattern to an edge of said first pattern is greater than or equal to a total thickness (t 1 ) of said N photosensitive layers excluding a thickness of said first photosensitive layer (t 2 ≧t 1 ).
5. A method of forming an N-layer mask pattern in N photosensitive layers (N≧2) formed on a substrate by exposure and development, comprising the steps of:
stacking said N photosensitive layers on said substrate so that they becomes lower in sensitivity from the first photosensitive layer which is the bottom layer of said N photosensitive layers, toward the N th photosensitive layer;
forming a first pattern of the same shape as a predetermined pattern to be formed on said substrate, in said first photosensitive layer;
forming a K th pattern in the K th photosensitive layer (N≧K≧2) so that said K th pattern is smaller than a (K−1) st pattern formed in the (K−1) st photosensitive layer and arranged inside said (K−1) st pattern;
forming said N-layer mask pattern comprising said N photosensitive layers in which said first to N th patterns are formed; and
etching said substrate by employing said N-layer mask pattern in order to form said predetermined pattern on said substrate.