Pattern writing apparatus and pattern writing method

1. A pattern writing apparatus for writing a pattern by applying light to a photosensitive material, comprising:

a light irradiating part for applying modulated light to each of irradiation regions of an irradiation region group which are arranged at equal pitches in two directions perpendicular to each other on a photosensitive material;

a scanning mechanism for scanning said irradiation region group over a photosensitive material in a scanning direction which is tilted relative to a direction of arrangement of said irradiation region group, and causing a plurality of irradiation regions to move relative to writing regions of a writing region group, respectively, said writing regions being fixedly arranged in said scanning direction and a direction perpendicular to said scanning direction at equal writing pitches on said photosensitive material; and

a controller controlling an amount of light applied to each of said writing regions on a photosensitive material by exercising individual ON/OFF control of light irradiation of said irradiation region group in synchronization with scanning of said irradiation region group, wherein

a center-to-center distance along said direction perpendicular to said scanning direction between adjacent irradiation regions arranged in a direction extending approximately along said scanning direction out of said two directions in which said irradiation regions are arranged is equal to said writing pitch,

a center-to-center distance along said scanning direction between said adjacent irradiation regions is equal to “a times” said writing pitch (a is an integer equal to or larger than 2),

said controller exercises ON/OFF control of said light irradiation once during relative movement of said irradiation region group by a distance equal to “n times” said writing pitch (n is an integer equal to or larger than 2), and

(a 2 +1) and n are relatively prime.

2. The pattern writing apparatus according to claim 1 , wherein

a number of irradiation regions which are arranged in said direction extending approximately along said scanning direction out of said two directions of arrangement of said irradiation region group is M which is an integral multiple of (a×n).

3. The pattern writing apparatus according to claim 1 , wherein

light irradiation of an irradiation region is controlled to be OFF before relative movement of said irradiation region group by a distance equal to n times said writing pitch is finished after light irradiation of said irradiation region is controlled to be ON.

4. The pattern writing apparatus according to claim 3 , wherein

relative movement of said irradiation region group by said writing pitch is performed in a time period from a time when light irradiation of said irradiation region is controlled to be ON to a time when light irradiation of said irradiation region is controlled to be OFF.

5. The pattern writing apparatus according to claim 3 , wherein

said light irradiating part comprises:

a light source which can be controlled ON/OFF; and

a spatial light modulator for spatially modulating light from said light source.

6. The pattern writing apparatus according to claim 1 , wherein

said light irradiating part comprises:

a spatial light modulator having a lattice arrangement of a light modulating element group which spatially modulates reflected light;

a light source emitting light applied to said spatial light modulator; and

an optical system directing light from said light modulating element group to said irradiation region group, respectively.

7. The pattern writing apparatus according to claim 6 , wherein

each element of said light modulating element group is a micromirror that changes its position.

8. The pattern writing apparatus according to claim 6 , wherein

a pattern is written on a photoresist film on a substrate for a printed circuit board.

9. The pattern writing apparatus according to claim 6 , wherein

said scanning mechanism continuously moves said irradiation region group.

10. A pattern writing method for writing a pattern by applying light to a photosensitive material, comprising the steps of:

applying modulated light to each of irradiation regions of an irradiation region group which are arranged at equal pitches in two directions perpendicular to each other on a photosensitive material, and scanning said irradiation region group over a photosensitive material in a scanning direction which is tilted relative to a direction of arrangement of said irradiation region group, to cause a plurality of irradiation regions to move relative to writing regions of a writing region group, respectively, said writing regions being fixedly arranged in said scanning direction and a direction perpendicular to said scanning direction at equal writing pitches on said photosensitive material; and

controlling an amount of light applied to each of said writing regions on a photosensitive material by exercising individual ON/OFF control of light irradiation of said irradiation region group in synchronization with scanning of said irradiation region group, wherein

a center-to-center distance along said direction perpendicular to said scanning direction between adjacent irradiation regions arranged in a direction extending approximately along said scanning direction out of said two directions in which said irradiation regions are arranged is equal to said writing pitch,

a center-to-center distance along said scanning direction between said adjacent irradiation regions is equal to “a times” said writing pitch (a is an integer equal to or larger than 2),

said controller exercises ON/OFF control of said light irradiation once during relative movement of said irradiation region group by a distance equal to “n times” said writing pitch (n is an integer equal to or larger than 2), and

(a 2 +1) and n are relatively prime.

11. The pattern writing method according to claim 10 , wherein

a number of irradiation regions which are arranged in said direction extending approximately along said scanning direction out of said two directions of arrangement of said irradiation region group is M which is an integral multiple of (a×n).

12. The pattern writing method according to claim 10 , wherein

light irradiation of an irradiation region is controlled to be OFF before relative movement of said irradiation region group by a distance equal to n times said writing pitch is finished after light irradiation of said irradiation region is controlled to be ON.

13. The pattern writing method according to claim 12 , wherein

relative movement of said irradiation region group by said writing pitch is performed in a time period from a time when light irradiation of said irradiation region is controlled to be ON to a time when light irradiation of said irradiation region is controlled to be OFF.

14. The pattern writing method according to claim 12 , wherein

modulated light is applied to each of said irradiation regions of said irradiation region group by spatially modulating light from a light source which can be controlled ON/OFF, and

light irradiation of said irradiation regions is controlled to be OFF by turning off said light source before relative movement of said irradiation region group by a distance equal to n times said writing pitch is finished.

15. The pattern writing method according to claim 10 , wherein

light is applied to said irradiation region group through a spatial light modulator having a lattice arrangement of a light modulating element group which spacially modulates reflected light.

16. The pattern writing method according to claim 15 , wherein

each element of said light modulating element group is a micromirror that changes its position.

17. The pattern writing method according to claim 10 , wherein

said pattern is written on a photoresist film on a substrate for a printed circuit board.

18. The pattern writing method according to claim 10 , wherein

said irradiation region group moves continuously.