Packaging for microLEDs for chip to chip communication
A microLED based optical chip-to-chip interconnect may optically couple chips in a variety of ways. The microLEDs may be positioned within a waveguide, and the interconnects may be arranged as direct connections, in bus topologies, or as repeaters.
1 . Chip-to-chip optical interconnect including a microLED, comprising:
a first semiconductor chip electrically coupled to an interposer;
a second semiconductor chip electrically coupled to the interposer;
the interposer including electrical signal paths electrically coupling the first semiconductor chip and the second semiconductor chip;
a first microLED having a pillar structure with an intrinsic region between an N-type layer and a P-type layer, the N-type layer contacting an n-metal contact and the P-type layer contacting a p-metal contact;
first circuitry, electrically coupled to the first semiconductor chip, for driving the first microLED based on data from the first semiconductor chip;
a first encapsulant substantially encapsulating the first microLED;
a first photodetector;
first amplification circuitry for amplifying signals from the first photodetector, the first amplification circuitry electrically coupled to provide electrical signals to the second semiconductor chip; and
a first waveguide optically coupling the first microLED and the first photodetector, the encapsulated first microLED within material of the first waveguide;
wherein the pillar structure of the first microLED includes a rear surface facing away from a path in the optical waveguide towards the first photodetector, and the first microLED includes metallization on the rear surface so as to reflect light towards the first photodetector; and
further comprising:
a second microLED;
second circuitry, electrically coupled to the first amplification circuitry, for driving the second microLED based on data from the first photodetector; and
a second optical waveguide optically coupling the second microLED and a third photodetector.
2 . The chip-to-chip optical interconnect of claim 1 , wherein the first waveguide is on a surface of the interposer.
3 . The chip-to-chip optical interconnect of claim 2 , wherein the first waveguide comprises a polymer waveguide.
4 . The chip-to-chip optical interconnect of claim 1 , wherein the encapsulated first microLED is in a hole in the first waveguide.
5 . The chip-to-chip optical interconnect of claim 1 , wherein the first semiconductor chip includes a processor and the second semiconductor chip is a memory chip.
6 . The chip-to-chip optical interconnect of claim 1 , wherein the N-type layer is a N-type GaN layer and the P-type layer is a P-type GaN layer.
7 . The chip-to-chip optical interconnect of claim 1 , wherein the N-type layer is on the n-metal contact and the P-type layer is under the p-metal contact.
8 . The chip-to-chip optical interconnect of claim 6 , wherein the intrinsic region is an intrinsic GaN region with a plurality of InGaN quantum wells.
9 . The chip-to-chip optical interconnect of claim 1 , wherein a first metal trace electrically connects the first microLED to the first circuitry and a second metal trace electrically connects the first photodetector to the first amplification circuitry.
10 . The chip-to-chip optical interconnect of claim 1 , wherein the first photodetector is butt-coupled to one end of the first waveguide opposite to the first microLED.
11 . The chip-to-chip optical interconnect of claim 1 , wherein the first photodetector is placed under one end of the first waveguide opposite to the first microLED.
12 . The chip-to-chip optical interconnect of claim 1 , wherein the encapsulated first microLED is on a silicon layer, the silicon layer being a lower cladding of the first waveguide.