Optical Chip Package Assembly for Precise Waveguide Alignment
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Solution Overview
Problem
Existing methods of fabricating semiconductor devices with optical and electrical components suffer from misalignment due to relative motion during the fabrication process, leading to inefficiencies in light energy transfer.
Innovation Solution
A multi-step singulation process involving dry etching and sawing with a tapered or rounded cutting profile is used to singulate COUPE and laser dies, followed by dielectric-to-dielectric and metal-to-metal bonding with an interposer, and filling the gap with optical glue to align coupling waveguides, reducing vertical and horizontal misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods are used to assemble optical and electrical components, then the fabrication process is simple and fast, but misalignment occurs due to relative motion between components, leading to optical losses
Solution Approach 1:
The patent applies preliminary action by forming recesses in the optical die and electrical die before assembly, and pre-aligning coupling waveguides with these recesses. This preliminary preparation ensures that when the dies are bonded together, the components are already positioned for optimal alignment, preventing misalignment issues that would otherwise occur during the fabrication process.
Solution Approach 2:
The patent uses an interposer as an intermediary component between the optical die and electrical die. The interposer provides a stable platform with precisely positioned bonding pads and alignment features, mediating the connection between the two dies and maintaining their relative positions to prevent misalignment during subsequent fabrication steps.
2Ease of manufacture
If components are bonded together early in the fabrication process, then assembly is simplified, but relative motion during subsequent steps causes misalignment
Solution Approach 1:
The patent performs preliminary alignment actions by forming recesses and positioning coupling waveguides before the bonding step. This ensures that when components are bonded early in the process, they are already pre-aligned, and subsequent fabrication steps cannot cause misalignment because the components are mechanically constrained by the recesses and interposer structure.
Solution Approach 2:
The patent segments the fabrication process into distinct stages: first forming recesses and positioning waveguides on separate dies, then bonding the dies to an interposer, and finally completing the assembly. This segmentation allows alignment-critical steps to be performed on individual components before assembly, avoiding the misalignment problem that would occur if all components were assembled and then subjected to subsequent processing.
3Loss of energy
If tight alignment tolerances are specified for coupling waveguides, then optical transmission efficiency is maximized, but manufacturing becomes more difficult and costly
Solution Approach 1:
The patent applies preliminary action by forming recesses in the optical die and electrical die that precisely define the positions of coupling waveguides before bonding. This preliminary positioning ensures tight alignment tolerances are achieved without requiring difficult post-assembly adjustments, as the waveguides are already correctly positioned when the dies are bonded to the interposer.
Solution Approach 2:
The interposer serves as an intermediary that provides precisely positioned bonding pads and mechanical constraints that maintain the relative positions of optical and electrical components. This intermediary structure makes it easier to achieve tight alignment tolerances, as the interposer's rigid structure and precise features guide the positioning of coupling waveguides during assembly, reducing manufacturing difficulty.
Data Source
AI summary
A semiconductor device and method of manufacturing are disclosed. The semiconductor device includes an optical die, a laser die, and an interposer. The optical die has photonic integrated circuits (PICs), electronic integrated circuits (EICs), and one or more first coupling waveguides. The laser die has at least one laser diode and one or more second coupling waveguides. The optical die and the laser die are bonded to a first side of the interposer using a metal-to-metal bonding, where at least one of the one or more first coupling waveguides is optically aligned with at least one of the one or more second coupling waveguides. An optical glue fills a gap between the aligned at least one of the one or more first coupling waveguides and the at least one of the one or more second coupling waveguides.