Integration of OE devices with ICs
Optical interconnects for IC chips may include optical sources and receivers integrated with the IC chips. MicroLEDs may be mounted on an interconnect layer of the IC chip, and embedded within a waveguide. Photodetectors to receive light from the waveguide may be fabricated in a top surface of a semiconductor substrate, below a level of the interconnect layer, but with a passageway for light through the interconnect layer.
1. An integrated circuit (IC) chip with optical components for an optical interconnect, comprising:
a semiconductor substrate containing transistors;
a stack of interconnect layers on top of the semiconductor substrate, the interconnect layers including alternating metal and dielectric layers;
a microLED on a pad on the stack of interconnect layers, with at least one electrical connection coupling the pad and at least one transistor of the semiconductor substrate; and
a photodetector integrated in the semiconductor substrate, with a light passageway to the photodetector through the stack of interconnect layers.
2. The IC chip with optical components of claim 1 , wherein the light passageway is provided by the stack of interconnect layers not having metal layers in a region over the photodetector.
3. The IC chip with optical components of claim 1 , wherein the light passageway is provided by a gap through the stack of interconnect layers in a region over the photodetector.
4. The IC chip with optical components of claim 3 , further comprising reflectors on edges of the gap.
5. The IC chip with optical components of claim 1 , further comprising a first waveguide on the stack of interconnect layers, the first waveguide extending over the light passageway to the photodetector through the stack of interconnect layers.
6. The IC chip with optical components of claim 5 , further comprising an angled reflector at an end of the first waveguide, the angled reflector positioned to reflect light from the waveguide to the photodetector through the stack of interconnect layers.
7. The IC chip with optical components of claim 1 , further comprising a second waveguide on the stack of interconnect layers, the microLED embedded in the second waveguide.
8. The IC chip with optical components of claim 1 , further comprising:
a further substrate, the further substrate positioned over the microLED; and
a waveguide on the further substrate, the waveguide positioned to receive light from the microLED.
9. The IC chip with optical components of claim 8 , further comprising a reflector, the reflector positioned to direct light from the microLED through the waveguide.
10. An optical interconnect for integrated circuit (IC) chips, comprising:
a first semiconductor substrate containing transistors;
a first stack of interconnect layers on top of the first semiconductor substrate, the interconnect layers including alternating metal and dielectric layers;
a microLED on a pad on the first stack of interconnect layers, with at least one electrical connection coupling the pad and at least one transistor of the semiconductor substrate;
a second semiconductor substrate containing transistors;
a second stack of interconnect layers on top of the second semiconductor substrate, the interconnect layers including alternating metal and dielectric layers;
a photodetector integrated in the second semiconductor substrate, with a light passageway to the photodetector through the second stack of interconnect layers; and
a waveguide configured to couple light from the microLED to the light passageway to the photodetector through the second stack of interconnect layers.
11. The optical interconnect of claim 10 , wherein the light passageway is provided by the second stack of interconnect layers not having metal layers in a region over the photodetector.
12. The optical interconnect of claim 10 , wherein the light passageway is provided by a gap through the stack of interconnect layers in a region over the photodetector.
13. The optical interconnect of claim 12 , further comprising reflectors on edges of the gap.
14. The optical interconnect of claim 10 , further comprising:
a further substrate, the further substrate positioned over the microLED;
with the waveguide on the further substrate, the waveguide positioned to receive light from the microLED.