Build-up printed wiring board substrate having a core layer that is part of a circuit
View Patent ↗Integrated circuits and processes for manufacturing integrated circuits are described that use printed wiring board substrates having a core layer that is part of the circuit of the printed wiring board. In a number of embodiments, the core layer is constructed from a carbon composite. In several embodiments, techniques are described for increasing the integrity of core layers in designs calling for high density clearance hole drilling. One embodiment of the invention includes a core layer that includes electrically conductive material and at least one build-up wiring portion formed on an outer surface of the core layer. In addition, the build-up portion comprises at least one micro wiring layer including a circuit that is electrically connected to the electrically conductive material in the core layer via a plated through hole.teh
1. A printed wiring board substrate, comprising:
a core layer that includes a layer of non-metallized carbon material;
layer of metal including an interior surface from which protrusions extend; and
at least one build-up wiring portion formed on the layer of metal;
wherein the layer of metal is clad by resin to one side of the non-metallized carbon material and a plurality of the protrusions contact the layer of non-metallized carbon material;
wherein the build-up portion includes a dielectric layer comprising non-reinforced dielectric formed on the layer of metal;
wherein the build-up portion further comprises at least one micro wiring layer including a circuit that is electrically connected to the core layer via a plated through hole;
wherein the build-up portion further comprises an electrical interconnect to which a semiconductor die can be direct mounted.
2. The printed wiring board substrate of claim 1 , wherein the coefficient of thermal expansion of the core layer is lower than the coefficient of thermal expansion of the at least one build-up portion.
3. The printed wiring board substrate of claim 1 , wherein the core layer is configured to act as a ground plane.
4. The printed wiring board substrate of claim 1 , wherein the core layer is configured to act as a power plane.
5. The printed wiring board substrate of claim 1 , wherein the core layer is configured to act as a split power and ground plane.
6. The printed wiring board substrate of claim 1 , wherein the core layer includes at least one ply of woven carbon fiber.
7. The printed wiring board substrate of claim 1 , wherein
the layer of metal includes an exterior surface that is planar.
8. The printed wiring board substrate of claim 1 , wherein:
the layer of non-metallized carbon material is clad on both sides with a layer of metal;
a second build-up wiring portion is formed on the other layer of metal;
a plated through hole connects a circuit on a micro wiring layer in the first build up wiring portion with a circuit on a micro wiring layer in the second build up wiring portion; and
the plated through hole is electrically isolated from the core layer by a resin filled clearance hole.
9. The printed wiring board substrate of claim 1 , wherein the core layer has a coefficient of thermal expansion of between 0 ppm/° C. and 12 ppm/° C. in the surface spreading direction.
10. The printed wiring board substrate of claim 9 , wherein the core layer has a coefficient of thermal expansion of between 0 ppm/° C. and 9 ppm/° C. in the surface spreading direction.
11. The printed wiring board substrate of claim 1 , wherein the core layer has a thermal conductivity of between 2 W/m.K and 500 W/m.K in the surface spreading direction.
12. The printed wiring board substrate of claim 1 , wherein the core layer has a thermal conductivity of between 50 W/m.K and 1000 W/m.K in the surface spreading direction.
13. The printed wiring board substrate of claim 1 , wherein the core layer has a tensile strength of between 5 msi and 35 msi.
14. The printed wiring board substrate of claim 1 , wherein the core layer has a tensile strength of between 10 msi and 40 msi.
15. The printed wiring board substrate of claim 1 , wherein the core layer has a dielectric constant that is greater than 6.0 at 1 MHz.
16. The printed wiring board of claim 1 , wherein the core layer has a thickness that is at least 30% of the thickness of the printed wiring board substrate.
17. A printed wiring board substrate, comprising:
a core layer that includes:
a layer of non-metallized carbon material;
a layer of metal including an interior surface from which protrusions extend;
wherein the layer of metal is bonded by resin to the layer of non-metallized carbon material and a plurality of the protrusions contact the layer of non-metallized carbon material; and
at least one build-up wiring portion formed on the layer of metal;
wherein the build-up portion further comprises at least one micro wiring layer including a circuit that is electrically connected to the core layer via a plated through hole;
wherein the build-up portion further comprises an electrical interconnect to which a semiconductor die can be direct mounted.
18. The printed wiring board substrate of claim 17 , wherein
the layer of metal includes an exterior surface that is planar.