Lead Frame Laser Chip Attachment for Photonics Alignment and Cooling
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Solution Overview
Problem
The alignment and attachment of semiconductor lasers to photonics chips are challenging due to variations in laser chip thickness and the inability to control operating temperature effectively, limiting precision and heat management.
Innovation Solution
A structure comprising a photonics chip with a cavity-mounted laser chip and a lead frame that supports the laser chip, allowing for precise alignment and improved heat dissipation through the lead frame's mechanical and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bump connections with redistribution layers and solder reflow are used to attach the laser chip to the photonics chip, then mechanical and electrical connections are established, but manufacturing precision is reduced due to difficulties in controlling solder flow and patterning variations
Solution Approach 1:
The patent introduces a lead frame as an intermediary component between the laser chip and the photonics chip. The lead frame includes a first portion that attaches to the laser chip and a second portion that attaches to the photonics chip, serving as a mediator that simplifies the attachment process while maintaining connection reliability and improving alignment precision through its rigid structure and pre-defined geometry
Solution Approach 2:
The attachment system is segmented into three distinct components: the laser chip, the lead frame, and the photonics chip. This segmentation allows each component to be optimized independently, with the lead frame serving as a dedicated attachment interface that separates the complex solder reflow process from the alignment-critical laser chip positioning
2Ease of manufacture
If the semiconductor laser is unpowered during the alignment process, then safety and simplicity are improved, but alignment precision deteriorates due to inability to use active feedback
Solution Approach 1:
The lead frame is pre-configured with specific geometric features and attachment geometries that establish precise alignment relationships before the laser chip is powered or activated. The rigid structure of the lead frame maintains predetermined alignment during the unpowered alignment process, eliminating the need for active feedback while preserving alignment precision through pre-established mechanical constraints
3Reliability
If bump connections are used as the primary heat conduction paths, then electrical connections are established, but heat sinking capability is limited due to the inherent thermal resistance of solder joints
Solution Approach 1:
The lead frame is designed to perform multiple functions simultaneously: it provides mechanical support for the laser chip, establishes electrical connections through its conductive structure, and serves as an enhanced heat sinking pathway with superior thermal conductivity compared to solder joints alone. This multi-functionality allows the same component to address electrical, mechanical, and thermal requirements
4Adaptability or versatility
If variations in laser chip thickness are present, then manufacturing flexibility is improved, but alignment precision deteriorates due to introduced dimensional variability
Solution Approach 1:
The lead frame features locally optimized attachment geometries at its first portion that contact the laser chip, with specific pad configurations and mechanical features designed to compensate for thickness variations. These localized structural adaptations ensure precise alignment and stable positioning despite variations in laser chip thickness, while maintaining manufacturing flexibility
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the precision of laser alignment and heat management, enabling efficient light transfer and thermal control, thus improving the performance of photonics chip assemblies.
Implementation Method 1
The bump connections provide the primary conduction paths to sink heat generated during the operation of the laser chip
Implementation Method 2
The laser chip may be attached inside a cavity that is formed in a substrate of the photonics chip
Data Source
AI summary
Structures including a photonics chip and a cavity-mounted laser chip, and methods of forming and using such structures. The structure comprises a photonics chip including a substrate and a cavity in the substrate. The structure further comprises a laser chip inside the cavity, and a lead frame comprising a first section attached to a portion of the laser chip and a second section attached to a portion of the photonics chip.