Infrared vertically-illuminated photodiode for chip alignment feedback

TL;DR

This paper presents vertically-illuminated photodiodes fabricated in a 45nm SOI process, capable of chip-to-chip alignment feedback at 1180 nm, with integrated processing for improved optical interconnects.

Contribution

It introduces a novel photodiode design and packaging for chip alignment feedback, integrating on-chip processing in a standard CMOS process.

Findings

Photodiodes responsive at 1180 nm suitable for chip communication

Wide field-of-view enables effective chip-to-board alignment

Monolithic integration allows on-chip processing of positional data

Abstract

We report on vertically-illuminated photodiodes fabricated in the GlobalFoundries 45nm 12SOI node and on a packaging concept for optically-interconnected chips. The photodiodes are responsive at 1180 nm, a wavelength currently used in chip-to-chip communications. They have further a wide field-of-view which enables chip-to-board positional feedback in chip-board assemblies. Monolithic integration enables on-chip processing of the positional data.