Circuitized substrate and method of making same
View Patent ↗A method of making a circuitized substrate such as a laminate chip carrier in which a polymer, e.g., Teflon, is used as a dielectric layer and a promotion adhesion layer of a polymer is used to securely adhere a conductive layer thereto which is deposited by plating. The resulting product is thus able to provide extremely narrow conductive circuitry for subsequent connections, e.g., to a semiconductor chip. Electroless plating is the preferred plating method with the dielectric immersed in a solution of conductive monomers, e.g., pyrrole monomer, the solution also possibly containing a seed material such as palladium-tin.
1. A method of making a circuitized substrate, said method comprising:
providing a polytetrafluoroethylene dielectric layer;
immersing said polytetrafluoroethylene dielectric layer in a solution including a conductive monomer and a seed material for a predetermined time period;
removing said polytetrafluoroethylene dielectric layer from said solution including said conductive monomer and said seed material and thereafter rinsing and drying said polytetrafluoroethylene dielectric layer; and
thereafter electrolessly plating a plurality of copper circuit lines on said polytetrafluoroethylene dielectric layer, each of said copper circuit lines having a peel strength within the range of from about 2.3 to about 3.5 pounds per square inch.
2. The method of claim 1 wherein said solution including said conductive monomer and said seed material is at a temperature of from about 20 degrees Celsius to about 30 degrees Celsius during said immersing of said dielectric polymer layer therein.
3. The method of claim 1 further comprising making at least one additional circuitized substrate using the steps of claim 1 and thereafter bonding said at least one additional circuitized substrate to said circuitized substrate.
4. The invention of claim 1 wherein said method is performed without a sputtering operation.
5. The method of claim 1 wherein said seed material is palladium-tin, said monomer comprising from about 0.001 to about 0.100 percent of said solution.
6. The method of claim 5 wherein said monomer comprises about 0.05 percent of said solution.
7. The method of claim 1 wherein said conductive monomer in said solution is selected from the group of monomers consisting of pyrrole monomer, aniline monomer, thiophene monomer and combinations thereof.
8. The method of claim 7 wherein said solution further includes an oxidant.
9. The method of claim 8 wherein said oxidant is selected from the group consisting of sodium persulfate, ferric chloride, cupric chloride, permanganate salt and compositions thereof.
10. A method of making a circuitized substrate, said method comprising:
providing a polytetrafluoroethylene dielectric layer;
immersing said polytetrafluoroethylene dielectric layer in a solution including a pyrrole conductive monomer and a palladium-tin seed material for a predetermined time period;
removing said polytetrafluoroethylene dielectric layer from said solution including said pyrrole conductive monomer and said palladium-tin seed material and thereafter rinsing and drying said polytetrafluoroethylene dielectric layer; and
thereafter electrolessly plating a plurality of copper circuit lines on said polytetrafluoroethylene dielectric layer, each of said copper circuit lines having a thickness of about 0.001 inch and a peel strength within the range of from about 2.3 to about 3.5 pounds per square inch.
11. The method of claim 10 further comprising making at least one additional circuitized substrate using the steps of claim 1 and thereafter bonding said at least one additional circuitized substrate to said circuitized substrate.
12. The invention of claim 10 wherein said method is performed without a sputtering operation.