Semiconductor light emitting device with thick metal layers
View Patent ↗A device according to embodiments of the invention includes a semiconductor structure including a light emitting layer sandwiched between an n-type region and a p-type region and first and second metal contacts, wherein the first metal contact is in direct contact with the n-type region and the second metal contact is in direct contact with the p-type region. First and second metal layers are disposed on the first and second metal contacts, respectively. The first and second metal layers are sufficiently thick to mechanically support the semiconductor structure. A portion of a sidewall the device adjacent to one of the first and second metal layers is reflective.
1. A method comprising:
providing a wafer of semiconductor devices, the wafer comprising:
a semiconductor structure comprising a light emitting layer sandwiched between an n-type region and a p-type region; and
first and second metal contacts for each semiconductor device, wherein each first metal contact is in direct contact with the n-type region and each second metal contact is in direct contact with the p-type region;
forming first and second metal layers on the first and second metal contacts of each semiconductor device on the wafer, respectively, wherein the first and second metal layers are sufficiently thick to support the semiconductor structure during later processing;
after forming first and second metal layers, forming an electrically insulating layer that fills spaces between the first and second metal layers; and
forming a reflective region disposed adjacent a sidewall of one of the first and second metal layers.
2. The method of claim 1 wherein forming first and second metal layers comprises plating first and second metal layers on the wafer.
3. The method of claim 1 wherein forming a reflective region comprises forming the electrically insulating layer with reflective material.
4. The method of claim 3 wherein the reflective material comprises TiO 2 mixed with one of silicone and epoxy.
5. The method of claim 1 wherein forming a reflective region comprises forming a reflective metal on a sidewall of one of the first and second metal layers.
6. The method of claim 5 further comprising:
attaching the wafer to handling foil; and
dicing the wafer into individual or groups of semiconductor devices while attached to the handling foil;
wherein forming a reflective metal on a sidewall of one of the first and second metal layers comprises depositing the reflective metal after dicing the wafer, while the wafer is still attached to the handling foil.
7. The method of claim 1 further comprising:
attaching the wafer to handling foil; and
dicing the wafer into individual or groups of semiconductor devices while attached to the handling foil;
wherein forming a reflective region disposed adjacent a sidewall of one of the first and second metal layers comprises disposing an electrically insulating reflective sheet adjacent to the sidewall in a region formed by dicing the wafer, while the wafer is still attached to the handling foil.