PIC Attach Cavity Wiring Between Z-Stop Supports for Electromigration
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Solution Overview
Problem
High electrical current requirements for external optical devices in photonic integrated circuits (PICs) lead to increased risks of electromigration failures in power delivery connections, especially at higher temperatures and power levels.
Innovation Solution
A PIC structure with electrical connections between z-stop supports on the sides of an attach cavity for an optical device, featuring a substrate with a cavity including shoulders and z-stop supports, and wires extending over the sides of the cavity between z-stop supports to provide larger electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high electrical current is delivered through single input and output wires at the end of the cavity, then power delivery to external optical devices is achieved, but electromigration failures increase especially at higher temperature and power requirements
Solution Approach 1:
The patent divides the power delivery function into multiple parallel current paths by adding intermediate connection points along the cavity sides. Instead of relying on a single wire at the end, the current is segmented and distributed through multiple wires connected to intermediate connection points, reducing the current density in each individual wire and mitigating electromigration effects.
Solution Approach 2:
The patent transitions from a one-dimensional power delivery approach (single wire at the end) to a two-dimensional distribution network by placing intermediate connection points along the sides of the cavity and connecting multiple wires between these points. This spatial redistribution creates additional current paths that reduce stress on any single conductor.
2Device complexity
If wire connections are made at the end of the cavity only, then device complexity is minimized, but thermal dissipation is insufficient for high power applications
Solution Approach 1:
The thermal management function is segmented by distributing heat sinks and intermediate connection points along the cavity sides rather than concentrating them at the end. This segmentation allows heat to be dissipated at multiple locations along the current path, reducing hot spots and improving overall thermal management without requiring a completely restructured connection system.
3Ease of manufacture
If single wire connections are used at the cavity end, then manufacturing is simplified, but electrical I/O capabilities are limited
Solution Approach 1:
The intermediate connection points along the cavity sides serve multiple functions: they provide intermediate electrical connections for power delivery, act as thermal management points, and enable additional I/O capabilities. This multi-functionality increases system versatility without proportionally increasing manufacturing complexity, as the same structural elements serve multiple purposes.
Data Source
AI summary
A photonic integrated circuit (PIC) structure includes a substrate, and a cavity defined in the substrate, the cavity including a shoulder at a side of the cavity. A plurality of z-stop supports for an optical device are also included. Each z-stop support of the plurality of z-stop supports is on a support portion of the shoulder. A wire extends over the side of the cavity and between at least two z-stop supports of the plurality of z-stop supports. An optical device is positioned on the plurality of z-stop supports in the cavity and electrically coupled to the wire. Electrical connections between z-stop supports allows larger sized electrical connections to the optical device to mitigate electromigration issues, and increased options for electrical connections.