LED having vertical contacts redistruted for flip chip mounting
View Patent ↗A light emitting diode (LED) structure has semiconductor layers, including a p-type layer, an active layer, and an n-Type layer. The p-type layer has a bottom surface, and the n-type layer has a top surface though which light is emitted. A copper layer has a first portion electrically connected to and opposing the bottom surface of the p-type layer. A dielectric wall extends through the copper layer to isolate a second portion of the copper layer from the first portion. A metal shunt electrically connects the second portion of the copper layer to the top surface of the n-type layer. P-metal electrodes electrically connect to the first portion, and n-metal electrodes electrically connect to the second portion, wherein the LED structure forms a flip chip. Other embodiments of the methods and structures are also described.
1. A light emitting diode (LED) structure comprising:
a plurality of semiconductor layers, including a first conductivity layer of a first type of semiconductor, an active layer, and a second conductivity layer of a second type of semiconductor, the first conductivity layer having an interior surface adjacent to the active layer and an exterior surface, and the second conductivity layer having an interior surface adjacent to the active layer and an exterior surface though which light is emitted;
a first metal portion and a second metal portion deposited over the exterior surface of the first conductivity layer, the first metal portion being electrically connected to the exterior surface of the first conductivity layer, the second metal portion being electrically insulated from the first conductivity layer and the first metal portion;
a first metal shunt portion formed integral with the LED structure and overlying a top portion of the exterior surface of the second conductivity layer;
a second metal shunt portion formed integral with the LED structure and comprising a deposited metal layer proximate at least one edge of the LED structure, the second metal shunt portion electrically connecting the second metal portion to the first metal shunt portion such that the second metal portion is electrically connected to the exterior surface of the second conductivity layer;
one or more first electrodes electrically connected to the first metal portion; and
one or more second electrodes electrically connected to the second metal portion such that the LED structure forms a flip chip, wherein at least some of the one or more second electrodes underlie the plurality of semiconductor layers.
2. The structure of claim 1 further comprising a first dielectric portion that electrically isolates the first metal portion from the second metal portion, and a second dielectric portion electrically isolating the second metal shunt portion from other than the exterior surface of the second conductivity layer.
3. The structure of claim 2 further comprising:
a third dielectric portion running along a section of the first metal portion; and
the one or more of the second electrodes being formed over the third dielectric and in electrical contact with the second metal portion.
4. The structure of claim 1 wherein the first metal portion is a first plated copper layer.
5. The structure of claim 4 wherein the second metal shunt portion is a second plated copper layer.
6. The structure of claim 1 further comprising a second dielectric portion formed along at least one edge of the second conductivity layer and isolating the first metal shunt portion from other than the exterior surface of the second conductivity layer.
7. The structure of claim 6 wherein the first metal shunt portion overlies the second dielectric portion and electrically contacts the exterior surface of the second conductivity layer, wherein the first metal shunt portion is formed around a periphery of the exterior surface of the second conductivity layer.
8. The structure of claim 1 wherein the first conductivity layer is a p-type layer and the second conductivity layer is an n-type layer.
9. The structure of claim 8 wherein the LED structure is a GaN based LED structure.