Segmented Ceramic Hermetic Package for High CTE Mismatch
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Solution Overview
Problem
Existing hermetic packages face challenges in handling high coefficient of thermal expansion (CTE) mismatch configurations, which can lead to ceramic cracking and compromised thermal performance, especially with the increased heat generation of high-performance semiconductor electronic components.
Innovation Solution
The hermetic package incorporates a metal base with a high CTE (>11 μm/m·K) surrounded by discrete ceramic wall segments with a lower CTE (<9 μm/m·K), where gaps between the ceramic segments are sealed with a connecting material, forming a ring wall that accommodates the CTE mismatch and enhances heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal materials with low CTE are selected to reduce CTE mismatch with ceramic materials, then ceramic cracking is reduced, but heat dissipation performance deteriorates
Solution Approach 1:
The ceramic wall is divided into multiple discrete ceramic wall segments separated by gaps, allowing each segment to independently accommodate thermal expansion differences with the metal base while maintaining overall structural integrity and hermetic sealing
Solution Approach 2:
The CTE of the metal base is intentionally selected to be higher than that of the ceramic wall segments, reversing the conventional approach. The metal base (CTE>11 μm/m·K) is surrounded by ceramic segments (CTE<9 μm/m·K), and the gaps between segments accommodate the expansion differential, enabling both high heat dissipation and ceramic cracking prevention
2Reliability
If discrete ceramic wall segments with gaps are used to accommodate CTE mismatch, then ceramic cracking is prevented, but package complexity increases
Solution Approach 1:
The ceramic wall is segmented into multiple discrete parts with gaps between them, positioned at corners of the ring wall where stress concentration occurs. This segmentation allows independent movement of each segment to accommodate CTE mismatch while the connecting material seals the gaps to maintain hermeticity
Solution Approach 2:
A connecting material is introduced as an intermediary substance to seal the gaps between adjacent ceramic wall segments. This connecting material accommodates the dimensional differences between segments while maintaining hermetic sealing, simplifying the overall structure compared to using a single continuous ceramic wall
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 configuration effectively manages high CTE mismatch without ceramic cracking, improving thermal performance and service reliability while allowing for cost-effective and customizable manufacturing.
Implementation Method 1
a hermetic package capable of handling a high coefficient of thermal expansion (CTE) mismatch configuration
Implementation Method 2
the metal base, which may have a much larger coefficient of thermal expansion (CTE) compared to the ceramic materials
Data Source
AI summary
The present disclosure relates to a hermetic package capable of handling a high coefficient of thermal expansion (CTE) mismatch configuration. The disclosed hermetic package includes a metal base and multiple segments that are discrete from each other. Herein, a gap exists between every two adjacent ceramic wall segments and is sealed with a connecting material. The ceramic wall segments with the connecting material form a ring wall, where the gap between every two adjacent ceramic wall segments is located at a corner of the ring wall. The metal base is either surrounded by the ring wall or underneath the ring wall.