Ceramic carrier and build up carrier for light-emitting diode (LED) array
View Patent ↗Circuit boards, LED lighting systems and methods of manufacture are described. A circuit board includes a ceramic carrier and a body on the ceramic carrier. The body includes dielectric layers and slots formed completely through a thickness of the dielectric layers. The slots are filled with a dielectric material. A conductive pad is provided on a surface of each of the slots opposite the ceramic carrier.
1. A method of manufacturing a light-emitting diode (LED) lighting system, the method comprising:
adhering a first ceramic carrier to a second ceramic carrier;
forming a plurality of first metal pads on each of the first and second ceramic carriers with spaces between each of the plurality of first metal pads on each of the first and second ceramic carriers;
forming a layer of a dielectric material over the plurality of first metal pads and filling the spaces between each of the plurality of first metal pads;
forming a plurality of vias in the layer of the dielectric material with a respective one of the plurality of vias formed over each of the plurality of first metal pads;
filling the plurality of vias with a metal material; and
forming a second metal pad over each of the plurality of vias; and
separating the first ceramic carrier from the second ceramic carrier after the forming the plurality of first metal pads, the forming the layer of the dielectric material, the forming the plurality of vias, the filling the plurality of vias and the forming the second metal pad.
2. The method of claim 1 , wherein the forming the plurality of first metal pads comprises:
forming a metal layer over the first ceramic carrier and the second ceramic carrier;
forming a photoresist layer over the metal layer;
removing portions of the photoresist layer in regions corresponding to the first metal pads to form a plurality of cavities;
filling the plurality of cavities with the metal material; and
removing all remaining portions of the photoresist layer.
3. The method of claim 1 , wherein the forming the plurality of vias in the layer of the dielectric material comprises one of drilling and laser direct imaging to form a plurality of micro-vias or slots.
4. The method of claim 1 , further comprising soldering individual LED devices onto the second metals pads.
5. The method of claim 1 , further comprising soldering a monolithic LED array onto the second metal pads.
6. The method of claim 1 , wherein the first and second ceramic carriers are formed from Aluminum Nitride (AlN).
7. The method of claim 1 , wherein the forming the plurality of vias further comprises forming the plurality of vias in pairs such that adjacent pairs of the plurality of vias are spaced apart by spaces each having a width in a range of 20 μm to 200 μm.
8. The method of claim 7 , wherein a spacing between each of the vias in each pair is smaller than the spacing between the adjacent pairs.
9. The method of claim 1 , wherein each of the plurality of vias has a width in a range of 50 μm to 200 μm.
10. The method of claim 1 , wherein the metal material comprises one of copper, silver and nickel.
11. The method of claim 1 , wherein the forming the layer of the dielectric material further comprises forming a stack of dielectric layers.
12. The method of claim 1 , wherein the stack of dielectric layers comprises an organic dielectric material.
13. The method of claim 12 , wherein the stack of dielectric layers has a total thickness in a range of 20 μm to 50 μm.
14. The method of claim 12 , wherein the stack of dielectric layers comprises a plurality of dielectric layers stacked one on top of the other with no intervening metal between adjacent layers.
15. The method of claim 1 , wherein the forming the plurality of vias in the layer of the dielectric material comprises one of drilling and laser direct imaging to form a plurality of micro-vias or slots.
16. The method of claim 1 , further comprising soldering individual LED devices onto the second metals pads.