Light-sensitive sheet comprising support, first and second light-sensitive layers and barrier layer

1. A light-sensitive sheet comprising a support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the barrier layer mainly comprises a resin having an affinity with water or a lower alcohol having 1 to 4 carbon atoms.

2. A light-sensitive sheet comprising a support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the barrier layer mainly comprises a resin that is soluble in water or a lower alcohol having 1 to 4 carbon atoms.

3. A light-sensitive sheet comprising a support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the barrier layer contains a polymerizable compound.

4. The light-sensitive sheet as defined in claim 3 , wherein the barrier layer has sensitivity to light, and light-sensitivity of the barrier layer is lower than the light-sensitivity of the first light-sensitive layer.

5. The light-sensitive sheet as defined in claim 3 , wherein the polymerizable compound contained in the harrier layer is a polymer having a polymerizable group.

6. The light-sensitive sheet as defined in claim 5 , wherein the polymer having the polymerizable group has an affinity to water or a lower alcohol having 1 to 4 carbon atoms.

7. The light-sensitive sheet as defined in claim 5 , wherein the polymer having the polymerizable group is soluble in water or a lower alcohol having 1 to 4 carbon atoms.

8. A light-sensitive sheet comprising a support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein light energy required for completing hardening reaction of the first light-sensitive layer and light energy required for completing hardening reaction of the second light-sensitive layer satisfy the condition of:

0.005 <A/B <0.5

in which A is the light energy required for completing hardening reaction of the second light-sensitive layer, and B is the light energy required for completing hardening reaction of the first light-sensitive layer.

9. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein light energy required for completing hardening reaction of the second light-sensitive layer and light energy required for initiating hardening reaction of the first light-sensitive layer satisfy the condition of:

1 <C/A <10

in which A is the light energy required for completing hardening reaction of the second light-sensitive layer, and C is the light energy required for initiating hardening reaction of the first light-sensitive layer.

10. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein each of the first and second light-sensitive layers independently further contains a sensitizer, and 5 an amount of the sensitizer contained in the second light-sensitive layer is larger than an amount of the sensitizer contained in the first light-sensitive layer.

11. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein an amount of the photo-polymerization initiator contained in the second light-sensitive layer is larger than an amount of the photo-polymerization initiator contained in the first light-sensitive layer.

12. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein an amount of the polymerizable compound contained in the second light-sensitive layer is larger than an amount of the polymerizable compound contained in the first light-sensitive layer.

13. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the first light-sensitive layer has a thickness in the range of 1 to 100 μm, the second light-sensitive layer has a thickness in the range of 0.1 to 15 μm, and the thickness of the first light-sensitive layer is larger than the thickness of the second light-sensitive layer.

14. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the first light-sensitive layer has absorption of light in the range of 0.1 to 1.0 at wavelength of 405 nm.

15. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the first light-sensitive layer or the second light-sensitive layer contains a compound having the absorption maximum within wavelength region of 380 to 430 nm.

16. The light-sensitive sheet as defined in claim 15 , wherein the compound having the absorption maximum within wavelength region of 380 to 430 nm is a sensitizer.

17. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the support comprises a transparent polymer film.

18. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the light-sensitive sheet has a shape of a long film.

19. The light-sensitive sheet as defined in claim 18 , wherein the light-sensitive sheet is wound up into a roll.

20. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the light-sensitive sheet comprises the support, the first light-sensitive layer, the second light-sensitive layer and a protective film in order, and wherein adhesion force between the support and the first light-sensitive layer and adhesion force between the protective film and the second light-sensitive layer satisfy the condition of:

Su>Pr

in which Su is the adhesion force between the support and the first light-sensitive layer, and Pr is the adhesion force between the protective film and the second light-sensitive layer.

21. A light-sensitive sheet comprising support, a first light-sensitive layer, a barrier layer and a second light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, wherein light-sensitivity of the second light-sensitive layer is higher than light-sensitivity of the first light-sensitive layer, and wherein the light-sensitive sheet is used for preparation of a printed circuit board.

22. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the barrier layer mainly comprises a resin having an affinity with water or a lower alcohol having 1 to 4 carbon atoms.

23. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the barrier layer mainly comprises a resin that is soluble in water or a lower alcohol having 1 to 4 carbon atoms.

24. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the barrier layer contains a polymerizable compound.

25. The light-sensitive laminate as defined in claim 24 , wherein the barrier layer has sensitivity to light, and light-sensitivity of the barrier layer is lower than the light-sensitivity of the first light-sensitive layer.

26. The light-sensitive laminate as defined in claim 24 , wherein the polymerizable compound contained in the barrier layer is a polymer having a polymerizable group.

27. The light-sensitive laminate as defined in claim 26 , wherein the polymer having the polymerizable group has an affinity to water or a lower alcohol having 1 to 4 carbon atoms.

28. The light-sensitive laminate as defined in claim 26 , wherein the polymer having the polymerizable group is soluble in water or a lower alcohol having 1 to 4 carbon atoms.

29. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the first light-sensitive layer has absorption of light in the range of 0.1 to 2.0 at wavelength of 405 nm.

30. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the first light-sensitive layer or the second light-sensitive layer contains a compound having the absorption maximum within wavelength region of 380 to 430 nm.

31. The light-sensitive laminate as defined in claim 30 , wherein the compound having the absorption maximum within wavelength region of 380 to 430 nm is a sensitizer.

32. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the substrate is a substrate for a printed circuit board.

33. A light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light-sensitive layers independently contains a binder, a polymerization compound and a photo-polymerization initiator, wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, and wherein the light-sensitive laminate comprises the substrate, the second light-sensitive layer and the first light-sensitive layer and a support in order.

34. A process for forming an image pattern, which comprises the steps of:

(1) exposing a light-sensitive laminate comprising a substrate, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, and wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, to light corresponding to the image pattern from the first light-sensitive layer to harden the first and second light-sensitive layers within the area exposed to light; and then

(2) developing the light-sensitive laminate whereby the unhardened areas of the first and second light-sensitive layers are removed to form the image pattern comprising an area where the hardened areas of the first and second light-sensitive layers remain on the substrate, and an area where the substrate is bared by removing the unhardened areas of the first and second light-sensitive layers.

35. The process as defined in claim 34 , wherein the light-sensitive laminate is exposed to light at the step of (1) by scanning the light-sensitive laminate with a laser beam.

36. The process as defined in claim 34 , wherein the light-sensitive laminate comprises the substrate, the second light-sensitive layer, the barrier layer, the first light-sensitive layer and a transparent support in order, and a step of removing the transparent support from the light-sensitive laminate is conducted between the steps (1) and (2).

37. A process for forming an image pattern, which comprises the steps of:

(1) exposing a light-sensitive laminate comprising a substrate, a second light-sensitive layer a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, to light corresponding to image patterns having at least two different light exposure energy levels from the first light-sensitive layer to harden the first and second light-sensitive layers within the area exposed to light having a higher light exposure energy level and to harden the second light-sensitive layer within the area exposed to light having a lower light exposure energy level; and then

(2) developing the light-sensitive laminate whereby the unhardened areas of the first and second light-sensitive layers are removed to form the image pattern comprising an area where the hardened, areas of the first, and second light-sensitive layers remain on the substrate, an area where the hardened area of the second light-sensitive layers remains on the substrate, and an area where the substrate is bared by removing the unhardened areas of the first and second light-sensitive layers.

38. The process as defined in claim 37 , wherein the light-sensitive laminate is exposed to light at the step of (1) by scanning the light-sensitive laminate with a laser beam.

39. The process as defined in claim 37 , wherein the light-sensitive laminate comprises the substrate, the second light-sensitive layer, the barrier layer, the first light-sensitive layer and a transparent support in order, and a step of removing the transparent support from the light-sensitive laminate is conducted between the steps (1) and (2).

40. The process as defined in claim 37 , wherein 10 sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer.

41. A process for forming a circuit pattern, which comprises the steps of:

(1) exposing a light-sensitive laminate comprising a substrate for a printed circuit board, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo: polymerization initiator, and wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer, to light corresponding to a circuit pattern from the first light-sensitive layer to harden the first and second light-sensitive layers within the area exposed to light; and then

(2) developing the light-sensitive laminate whereby the unhardened areas of the first and second light-sensitive layers are removed to form the circuit pattern comprising an area where the hardened areas of the first and second light-sensitive layers remain on the substrate, and an area where the substrate is bared by removing the unhardened areas of the first and second light-sensitive layers.

42. The process as defined in claim 41 , wherein the light-sensitive laminate is exposed to light at the step of (1) by scanning the light-sensitive laminate with a laser beam.

43. The process as defined in claim 41 , wherein the light-sensitive laminate comprises the substrate, the second light-sensitive layer, the barrier layer, the first light-sensitive layer and a transparent support in order, and a step of removing the transparent support from the light-sensitive laminate is conducted between the steps (1) and (2).

44. A process for forming a circuit pattern, which comprises the steps of:

(1) exposing a light-sensitive laminate comprising a substrate having holes for a printed circuit hoard, a second light-sensitive layer, a barrier layer and a first light-sensitive layer in order, wherein each of the first and second light sensitive layers independently contains a binder, a polymerizable compound and a photo-polymerization initiator, to light having at least two different light exposure energy levels from the first light-sensitive layer to harden the first and second light-sensitive layers within the area corresponding to the holes and neighborhoods thereof exposed to light having a higher light exposure energy level and to harden the second light-sensitive layer within the area corresponding to a wire pattern exposed to light having a lower light exposure energy level; and then

(2) developing the light-sensitive laminate whereby the unhardened areas of the first and second light-sensitive layers are removed to form the circuit pattern, comprising an area where the hardened areas of the first and second light-sensitive layers remain on the substrate, an area where the hardened area of the second light-sensitive layers remains on the substrate, and an area where the substrate is bared by removing the unhardened areas of the first and second light-sensitive layers.

45. The process as defined in claim 44 , wherein the light-sensitive laminate is exposed to light at the step of (1) by scanning the light-sensitive laminate with a laser beam.

46. The process as defined in claim 44 , wherein the light-sensitive laminate comprises the substrate, the second light-sensitive layer, the barrier layer, the first light-sensitive layer and a transparent support in order, and a step of removing the transparent support from the light-sensitive laminate is conducted between the steps (1) and (2).

47. The process as defined in claim 44 , wherein sensitivity of the first light-sensitive layer is lower than sensitivity of the second light-sensitive layer.