LED WITH STRESS-BUFFER LAYER UNDER METALLIZATION LAYER

摘要

Semiconductor LED layers are epitaxially gown on a patterned surface of a sapphire substrate (10). The patterned surface improves light extraction. The LED layers include a p-type layer and an n-type layer. The LED layers are etched to expose the n-type layer. One or more first metal layers are patterned to electrically contact the p-type layer and the n-type layer to form a p-metal contact (32) and an n-metal contact (33). A dielectric polymer stress-buffer layer (36) is spin-coated over the first metal layers to form a substantially planar surface over the first metal layers. The stress-buffer layer has openings exposing the p-metal contact and the n-metal contact. Metal solder pads (44, 45) are formed over the stress-buffer layer and electrically contact the p-metal contact and the n-metal contact through the openings in the stress-buffer layer. The stress-buffer layer acts as a buffer to accommodate differences in CTEs of the solder pads and underlying layers.

主权项

1. A light emitting device comprising:
a substantially transparent growth substrate; light emitting diode (LED) layers disposed on the substrate, the LED layers including a p-type layer and an n-type layer, wherein the LED layers are etched to expose one of the p-type layer and n-type layer for electrically connecting to a p-metal contact or an n-metal contact, wherein the etch also creates a trench surrounding the device; one or more metal contact layers electrically contacting the p-type layer and the n-type layer to form the p-metal contact and the n-metal contact; a dielectric polymer stress-buffer layer disposed over the p-metal contact and the n-metal contact, the stress-buffer layer forming a substantially planar surface over the p-metal contact and the n-metal contact, the stress-buffer layer having two or more openings exposing a portion of the p-metal contact and a portion of the n-metal contact, wherein the stress-buffer layer at least partially fills the trench; and metal solder pads disposed over the stress-buffer layer, wherein the metal solder pads are electrically connected to the p-metal contact and the n-metal contact through the openings in the stress-buffer layer.