Methods of manufacturing printed circuit boards with stacked micro vias
View Patent ↗Methods of manufacturing printed circuit boards having circuit layers laminated with stacked (or staggered) micro via(s). Aspects of embodiments of the present invention are directed to a method of manufacturing a printed circuit board with Z-axis interconnect(s) or micro via(s) that can eliminate a need for plating micro vias and/or eliminate a need for planarizing plated bumps of a surface, that can be fabricated with one or two lamination cycles, and/or that can have carrier-to-carrier (or substrate-to-substrate) attachments with conductive vias, each filled with a conductive material (e.g., with a conductive paste) in the Z-axis. In one embodiment, a printed circuit board having a plurality of circuit layers with at least one z-axis interconnect can be fabricated using a single lamination cycle.
1. A method of manufacturing a printed circuit board having a plurality of circuit layers with at least one z-axis interconnect using a single lamination cycle, the method comprising:
attaching a plurality of one-metal layer carriers with each other after parallel processing each of the plurality of one-metal layer carriers, wherein the parallel processing of at least one of the plurality of one-metal layer carriers comprises:
imaging at least one photo resist onto a substrate having at least one copper foil formed on at least one side of the substrate;
etching off the at least one copper foil from the substrate with exception of at least one part of the at least one copper foil covered by the at least one photo resist;
stripping off the at least one photo resist to expose the at least one part of the at least one copper foil to form at least one copper foil pad for one of the plurality of circuit layers;
applying a lamination adhesive on the substrate;
applying a protective film on the lamination adhesive;
forming at least one micro via into the substrate to expose the at least one copper foil pad at a side of the substrate opposite to the at least one side of the substrate;
filling at least one conductive paste into the at least one micro via formed in the substrate; and
removing the protective film to expose the lamination adhesive on the substrate for attachment.
2. The method of claim 1 , wherein the attaching of the plurality of one-metal layer carriers comprises:
aligning the plurality of one-metal layer carriers adjacent to each other; and
curing the lamination adhesive on the substrate of each the plurality of one-metal layer carriers to laminate the plurality of one-metal layer carriers with each other.
3. The method of claim 2 , wherein the laminated one-metal layer carriers comprise a first side on which the one of the plurality of circuit layers is disposed, and a second side opposite to the first side.
4. The method of claim 3 , further comprising:
disposing a second one of the plurality of circuit layers on the second side of the laminated one-metal layer carriers to complete a formation of the printed circuit board.
5. The method of claim 4 , wherein a third one of the plurality of circuit layers is disposed between the one of the plurality of circuit layers and the second one of the plurality of circuit layers.
6. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit board manufactured using the single lamination cycle comprises at least four circuit layers.
7. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit board manufactured using the single lamination cycle comprises at least five circuit layers.
8. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit board manufactured using the single lamination cycle comprises at least six circuit layers.
9. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit board manufactured using the single lamination cycle comprises at least seven circuit layers.
10. The method of claim 9 , wherein the polyester film is Mylar.
11. The method of claim 1 , wherein the substrate comprises a core material selected from the group consisting of metal, ceramic, FR4, GPY, and combinations thereof.
12. The method of claim 1 , wherein the protective film comprises a material selected from the group consisting of polyester, oriented polypropylene, polyvinylfluoride, polyethylene, high density polyethylene, polyethylene napthalate, pacothane, polymethylpentene, and combinations thereof.
13. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit board manufactured using the single lamination cycle comprises at least eight circuit layers.
14. The method of claim 1 , wherein the at least one micro via is formed by laser drilling.
15. The method of claim 1 , wherein the at least one micro via is formed by mechanical drilling.
16. The method of claim 1 , wherein the at least one photo resist is imaged by laser-direct-imaging.
17. The method of claim 1 , wherein the at least one photo resist is imaged by photo imaging, silkscreen imaging, offset imaging, and/or inkjet imaging.
18. The method of claim 1 , wherein the parallel processing of at least another one of the plurality of one-metal layer carriers comprises:
imaging at least one photo resist onto a metal plate having at least one copper flash formed on at least one side of the metal plate to develop at least one cavity;
plating copper into the at least one cavity;
stripping off the at least one photo resist to form at least one copper foil pad for one of the plurality of circuit layers;
applying prepreg on the at least one copper foil pad to laminate the prepreg with the metal plate;
curing the prepreg laminated with the metal plate with the at least one copper foil pad and the at least one copper flash therebetween;
peeling the at least one copper foil pad and the at least one copper flash with the cured prepreg from the metal plate; and
etching off the at least one copper flash to expose the at least one copper foil pad on the cured prepreg.
19. The method of claim 18 , wherein the parallel processing of the at least another one of the plurality of one-metal layer carriers further comprises:
forming at least one micro via into the cured prepreg to expose the at least one copper foil pad at opposite sides of the cured prepreg; and
filling at least one conductive paste into the at least one micro via formed in the cured prepreg.
20. The method of claim 1 , wherein the plurality of circuit layers of the printed circuit comprises an odd number of circuit layers.
21. A method of manufacturing a printed circuit board having a plurality of circuit layers with at least one z-axis interconnect using a single lamination cycle, the method comprising:
attaching a plurality of one-metal layer carriers with each other after parallel processing each of the plurality of one-metal layer carriers, wherein the parallel processing of at least one of the plurality of one-metal layer carriers comprises:
imaging at least one photo resist onto a metal plate having at least one copper flash formed on at least one side of the metal plate to develop at least one cavity;
plating copper into the at least one cavity;
stripping off the at least one photo resist to form at least one copper foil pad for one of the plurality of circuit layers;
applying a first side of a prepreg on the at least one copper foil pad to laminate the prepreg with the metal plate;
curing the prepreg laminated with the metal plate with the at least one copper foil pad and the at least one copper flash therebetween;
peeling the at least one copper foil pad and the at least one copper flash with the cured prepreg from the metal plate;
etching off the at least one copper flash to expose the at least one copper foil pad on the cured prepreg;
applying a lamination adhesive on the cured prepreg;
applying a protective film on the lamination adhesive;
forming at least one micro via into the cured prepreg to expose the at least one copper foil pad at a second side of the cured prepreg opposite to the first side of the cured prepreg;
filling at least one conductive paste into the at least one micro via formed in the cured prepreg; and
removing the protective film to expose the lamination adhesive on the cured prepreg for attachment.