Methods of forming metal layers using multi-layer lift-off patterns
View Patent ↗Methods of forming interconnections for an electronic device including a substrate may be provided. For example, first and second patterned layers may be formed on the substrate wherein an opening in the first and second patterned layers exposes portions of the substrate, wherein the first and second patterned layers have different compositions, and wherein the first patterned layer is between the second patterned layer and the substrate. A metal layer may be formed on the second patterned layer and on portions of the substrate exposed through the opening in the first and second patterned layers. The second patterned layer and portions of the metal layer thereon may be removed while maintaining portions of the metal layer on the portions of the substrate exposed through the opening. After removing the second mask layer, solder may be provided on the metal layer.
1. A method of forming an interconnection for an electronic device including a substrate, the method comprising:
forming first and second patterned layers on the substrate wherein an opening in the first and second patterned layers exposes portions of the substrate, wherein the first and second patterned layers have different compositions, and wherein the first patterned layer is between the second patterned layer and the substrate;
forming a metal layer on the second patterned layer and on portions of the substrate exposed through the opening in the first and second patterned layers;
removing the second patterned layer and portions of the metal layer thereon while maintaining portions of the metal layer on the portions of the substrate exposed through the opening; and
after removing the second patterned layer, providing solder on the metal layer.
2. A method according to claim 1 wherein providing the solder on the metal layer comprises providing a preformed solder mass on the metal layer while maintaining the first patterned layer after removing the second patterned layer, and after providing the preformed solder mass, bonding the preformed solder mass to the metal layer.
3. A method according to claim 1 wherein the metal layer comprises a first metal layer, the method further comprising:
after removing the second patterned layer and before providing the solder, selectively forming a second metal layer on the first metal layer so that the second metal layer is between the solder and the first metal layer.
4. A method according to claim 3 wherein selectively forming the second metal layer comprises plating the second metal layer.
5. A method according to claim 1 wherein forming the metal layer comprises sputtering the metal layer.
6. A method according to claim 1 wherein providing solder on the metal layer comprises providing solder on the metal layer while maintaining the first patterned layer.
7. A method according to claim 6 wherein the first patterned layer comprises a photo-imageable epoxy.
8. A method according to claim 1 wherein forming the first and second patterned layers comprises,
forming first and second photo-sensitive layers on the substrate,
selectively exposing the first and second photo-sensitive layers to radiation using a photo-mask, and
after forming the first and second photo-sensitive layers and after selectively exposing the first and second photo-sensitive layer, developing the first and second photo-sensitive layers.
9. A method according to claim 8 wherein forming the first and second photo-sensitive layers comprises coating the first and second photo-sensitive layers using different solvents for the first and second photo-sensitive layers.
10. A method according to claim 8 wherein the first photo-sensitive layer has a first photo-sensitivity, wherein the second photo-sensitive layer has a second photo-sensitivity, and wherein the first and second photo-sensitivities are different.
11. A method according to claim 1 wherein forming the first and second patterned layers comprises providing the first and second patterned layers as a pre-laminated dry film, and then applying the pre-laminated dry film to the substrate.
12. A method of forming an interconnection for an electronic device including a substrate, the method comprising:
forming first and second patterned layers on the substrate wherein an opening in the first and second patterned layers exposes portions of the substrate, wherein the first and second patterned layers have different compositions, and wherein the first patterned layer is between the second patterned layer and the substrate;
forming a metal layer on the second patterned layer and on portions of the substrate exposed through the opening in the first and second patterned layers; and
removing the second patterned layer and portions of the metal layer thereon while maintaining the first patterned layer and portions of the metal layer on the portions of the substrate exposed through the opening wherein the metal layer is spaced apart from the first patterned layer.
13. A method according to claim 12 wherein the metal layer comprises a first metal layer, the method further comprising:
after removing the second patterned layer, selectively forming a second metal layer on the first metal layer.
14. A method according to claim 13 wherein selectively forming the second metal layer comprises selectively forming the second metal layer while maintaining the first patterned layer.
15. A method according to claim 14 wherein the first patterned layer comprises a photo-imageable epoxy.
16. A method according to claim 13 further comprising:
after selectively forming the second metal layer, providing solder on the second metal layer.
17. A method according to claim 16 wherein providing solder comprises providing a preformed solder mass on the second metal layer while maintaining the first patterned layer, and after providing the preformed solder mass, bonding the preformed solder mass to the second metal layer.
18. A method according to claim 13 wherein selectively forming the second metal layer comprises plating the second metal layer.
19. A method according to claim 12 wherein forming the metal layer comprises sputtering the first metal layer.
20. A method according to claim 12 wherein forming the first and second patterned layers comprises,
forming first and second photo-sensitive layers on the substrate,
selectively exposing the first and second photo-sensitive layers to radiation using a photo-mask, and
after forming the first and second photo-sensitive layers and after selectively exposing the first and second photo-sensitive layer, developing the first and second photo-sensitive layers.
21. A method according to claim 20 wherein forming the first and second photo-sensitive layers comprises coating the first and second photo-sensitive layers using different solvents for the first and second photo-sensitive layers.
22. A method according to claim 20 wherein the first photo-sensitive layer has a first photo-sensitivity, wherein the second photo-sensitive layer has a second photo-sensitivity, and wherein the first and second photo-sensitivities are different.
23. A method according to claim 12 wherein forming the first and second patterned layers comprises providing the first and second patterned layers as a pre-laminated dry film, and then applying the pre-laminated dry film to the substrate.
24. A method according to claim 12 wherein portions of the substrate are exposed between the metal layer and the first patterned layer.
25. A method according to claim 1 wherein the metal layer is spaced apart from the first patterned layer.
26. A method according to claim 25 wherein portions of the substrate are exposed between the metal layer and the first patterned layer.
27. A method according to claim 1 further comprising:
after providing the solder on the metal layer, reflowing the solder.
28. A method according to claim 16 further comprising:
after providing the solder on the second metal layer, reflowing the solder.
29. A method according to claim 1 wherein portions of the first patterned layer adjacent the opening are undercut relative to the second patterned layer.
30. A method according to claim 12 wherein portions of the first patterned layer adjacent the opening are undercut relative to the second patterned layer.