Adhesion promotion in printed circuit boards
View Patent ↗An adhesion promotion process and composition for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board. The composition contains a corrosion inhibitor, an inorganic acid, and an alcohol which is effective to increase copper-loading in the composition.
1. A process for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board, the process comprising:
exposing the copper conducting layer to an adhesion promotion composition comprising a corrosion inhibitor, an inorganic acid, an oxidizing agent, and an alcohol or derivative thereof which is effective to increase copper-loading in the composition, wherein the adhesion promotion composition is initially substantially free of transition metals having a tendency to destabilize the oxidizing agent, to thereby yield a microroughened copper surface;
wherein the concentration of the alcohol or derivative thereof is at least about 0.01 wt % and no greater than about 20 wt %.
2. The process of claim 1 wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %.
3. The process of claim 1 wherein the adhesion promotion composition has a chloride ion in a concentration between 20 ppm and 100 ppm.
4. The process of claim 1 wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition.
5. The process of claim 1 wherein the adhesion promotion composition further comprises dodecylbenzene sulfonic acid (DDBSA) as an anionic surfactant.
6. The process of claim 1 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid.
7. The process of claim 1 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid, wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition, and wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %.
8. The process of claim 1 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid, wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition, wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %, and wherein the adhesion promotion composition has a chloride ion in a concentration between 20 ppm and 100 ppm.
9. An adhesion promotion composition for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board, the adhesion promotion composition comprising a corrosion inhibitor, an inorganic acid, an oxidizing agent, and an oligomeric alcohol or oligomeric alcohol derivative which is effective to increase copper-loading in the composition, wherein the adhesion promotion composition is initially substantially free of transition metals having a tendency to destabilize the oxidizing agent;
wherein the alcohol or alcohol derivative is present in a concentration of at least about 0.01 wt % and no greater than about 20 wt %.
10. The adhesion promotion composition of claim 9 wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %.
11. The adhesion promotion composition of claim 9 wherein the adhesion promotion composition has a chloride ion in a concentration between 20 ppm and 100 ppm.
12. The adhesion promotion composition of claim 9 wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition.
13. The adhesion promotion composition of claim 9 wherein the adhesion promotion composition further comprises dodecylbenzene sulfonic acid (DDBSA) as an anionic surfactant.
14. The adhesion promotion composition of claim 9 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid.
15. The adhesion promotion composition of claim 9 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid, wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition, and wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %.
16. The adhesion promotion composition of claim 9 wherein the inorganic acid is a mixture of sulfuric acid and nitric acid, wherein the corrosion inhibitor is selected from the group consisting of triazoles, tetrazoles, imidazoles and combinations thereof and constitutes between about 0.1 wt % and about 20 wt % of the adhesion promotion composition, wherein the concentration of the alcohol or derivative thereof is at least about 0.5 wt % and no greater than about 10 wt %, and wherein the adhesion promotion composition has a chloride ion in a concentration between 20 ppm and 100 ppm.