Circuitized substrates utilizing smooth-sided conductive layers as part thereof
View Patent ↗A circuitized substrate in which two conductive layers (e.g., electroplated copper foil) are bonded (e.g., laminated) to an interim dielectric layer. Each of the two foil surfaces which physically bond to the dielectric are smooth (e.g., preferably by chemical processing) and include a thin, organic layer thereon, while the outer surfaces of both foils are also smooth (e.g., preferably also using a chemical processing step). One of these resulting conductive layers may function as a ground or voltage plane while the other may function as a signal plane with a plurality of individual signal lines as part thereof. An electrical assembly and an information handling system utilizing such a circuitized substrate are also provided.
1. A circuitized substrate comprising:
at least one dielectric layer having first and second opposite sides;
first and second electrically conductive layers, each of said first and second electrically conductive layers having a first smooth side having an RMS surface roughness within the range of from about 0.1 to about 0.6 microns and further including a thin organic layer thereon and bonded to said first and second opposite sides of said at least one dielectric layer, respectively, and a second etched smooth side opposite said first smooth side and not including an organic layer thereon, said second etched smooth side for being bonded directly to a dielectric layer other than said at least one dielectric layer, both said first and second smooth sides of said first and second electrically conductive layers each having a surface roughness that substantially prevents electrical signal attenuation when electrical signals pass near the surfaces of said sides; and
a circuit pattern formed within at least one of said electrically conductive layers having said first smooth side and said second etched smooth side.
2. The circuitized substrate of claim 1 wherein said at least one dielectric layer is an organic dielectric material selected from the group of polymer materials consisting of fiberglass-reinforced epoxy resins, polytetrafluoroethylene, polyimides, polyamides, cyanate resins, polyphenylene ether resins, photoimageable materials, and combinations thereof.
3. The circuitized substrate of claim 1 wherein said first and second electrically conductive layers are comprised of copper or copper alloy material.
4. The circuitized substrate of claim 3 wherein said copper or copper alloy material is electrodeposited copper.
5. The circuitized substrate of claim 1 wherein said thin organic layer comprises benzotriazole and has a thickness of from about 50 Angstroms to about 500 Angstroms.
6. The circuitized substrate of claim 1 further including additional dielectric and electrically conductive layers on opposite sides of said circuitized substrate having said at least one dielectric layer and said first and second electrically conductive layers, and a circuit pattern within selected ones of said additional electrically conductive layers, at least two of said additional dielectric layers being bonded directly to said second smooth sides of said first and second electrically conductive layers not having said organic layer thereon, respectively.
7. The circuitized substrate of claim 6 wherein the total number of dielectric layers and electrically conductive layers within said circuitized substrate is greater than ten.
8. The invention of claim 1 further including at least one electrical component positioned on and electrically coupled to said circuitized substrate, said circuitized substrate and said at least one electrical component comprising an electrical assembly.
9. The invention of claim 8 wherein said at least one electrical component comprises a semiconductor chip.
10. The invention of claim 8 further including a housing, said electrical assembly being positioned within said housing, said housing and said electrical assembly comprising an information handling system.