Fresnel phase plate lenses for through-wafer optical interconnections

Area of Science:

• Optoelectronics
• Materials Science
• Integrated Circuit Design

Background:

• The trade-off between optical and electrical interconnects for 3-D architectures remains unclear.
• 3-D interconnection structures require clarification on vertical link performance.
• Hybrid wafer-scale integration (WSI) needs experimental data for optical interconnects.

Purpose of the Study:

• To clarify the optical vs. electrical interconnect trade-off for 3-D architectures.
• To obtain experimental data on optical interconnect performance in hybrid-WSI.
• To design and fabricate lens arrays for through-wafer optical interconnects.

Main Methods:

• Design and fabrication of silicon dioxide (SiO(2)) Fresnel phase plate lens arrays.
• Development of 1.3-micrometer wavelength through-wafer optical interconnects.
• Utilizing VLSI-compatible processes with submicron minimum linewidths and 0.8 numerical aperture (N.A.) lenses.

Main Results:

• Demonstrated fabrication of SiO(2) Fresnel phase plate lens arrays.
• Achieved 0.8 N.A. lenses with submicron linewidths compatible with VLSI processes.
• Preliminary results show obtainable optical interconnect densities comparable to on-chip bonding pads (approx. 250-micrometer pitch).

Conclusions:

• The fabricated lens arrays are suitable for through-wafer optical interconnects.
• High-density vertical optical interconnects are achievable in 3-D architectures.
• Experimental data will help define the optical vs. electrical interconnect trade-off for hybrid-WSI.