Optical Package Contact Routing to Prevent Noble Metal Contamination
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Solution Overview
Problem
Existing technologies face challenges in integrating optical and electrical components effectively, particularly due to contamination issues from noble metals used in electrical contacts, which can cause process defects during semiconductor fabrication.
Innovation Solution
The use of noble metals for electrical contacts in laser dies is combined with more compatible metals for overlying electrical routing, and the laser dies are bonded to an optical interposer, ensuring contamination is avoided while maintaining the benefits of noble metals, using processes like epitaxial growth and photolithographic masking to form laser diodes with recessed contacts and compatible routing layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metals are used for electrical contacts in laser dies, then contact quality is improved, but contamination issues occur during semiconductor fabrication
Solution Approach 1:
The electrical contact structure is segmented into multiple functional layers: a noble metal layer (gold or platinum) for high-quality electrical contact, and a separate compatible metal layer (aluminum or copper) for routing that does not cause contamination. This segmentation allows each layer to perform its specific function without causing harmful effects to the fabrication process.
Solution Approach 2:
A compatible metal layer acts as an intermediary between the noble metal contact layer and the semiconductor fabrication process. This intermediate layer prevents direct interaction between noble metals and subsequent fabrication processes, thereby eliminating contamination while preserving the electrical contact quality provided by the noble metal.
2Reliability
If noble metals are used throughout the electrical routing, then contact quality is maintained, but fabrication process compatibility is reduced
Solution Approach 1:
Different regions of the electrical structure have different material compositions optimized for their specific functions: noble metals are used locally where high electrical contact quality is critical (contact regions), while compatible metals are used locally in routing regions where fabrication process compatibility is the priority. This local differentiation resolves the contradiction between contact quality and manufacturability.
3Adaptability or versatility
If electrical and optical components are integrated in the same package, then functionality is enhanced, but contamination risks increase
Solution Approach 1:
The integrated package is segmented into distinct electrical and optical sub-systems with separate material compositions. The electrical components use compatible metals for routing, while optical components can utilize noble metals where needed. This segmentation prevents cross-contamination between the two subsystems during fabrication while maintaining the benefits of integration.
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
This approach allows for improved contact quality, reduced contamination, and enhanced physical isolation, facilitating efficient integration of optical and electrical components in semiconductor packages.
Implementation Method 1
using processes like epitaxial growth and photolithographic masking to form laser diodes
Implementation Method 2
using processes like epitaxial growth and photolithographic masking to form laser diodes
Data Source
AI summary
A method includes forming a laser diode structure including an active layer sandwiched between an n-type contact layer and a p-type contact layer; forming an n-type contact on the n-type contact layer, wherein the n-type contact includes a first noble metal; forming a p-type contact on the p-type contact layer, wherein the p-type contact includes a second noble metal; forming a conductive routing layer on the n-type contact and on the p-type contact, wherein the conductive routing layer is free of noble metals, wherein the conductive routing layer fully covers the n-type contact and the p-type contact; and forming a passivation layer over the conductive routing layer.