Hermetic Sensor Casing Structure for Low-Stress Implantable Packaging
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Solution Overview
Problem
Existing sensor devices, especially implantable ones, face challenges due to mechanical stress and humidity, which can damage the semiconductor platform and limit the device's lifetime.
Innovation Solution
A sensor device design featuring a rigid casing formed by a bottom and top casing element, where the top casing element contacts the semiconductor platform, and the stress is primarily transferred to the bottom casing element, maintaining hermetic sealing and minimizing mechanical stress on the semiconductor platform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top casing is bonded to the semiconductor platform to form a sealed cavity, then hermetic sealing is achieved, but mechanical stress is transferred to the semiconductor platform causing damage
Solution Approach 1:
The casing is divided into two separate elements: a rigid top casing element for hermetic sealing and a flexible bottom casing element for stress absorption. This segmentation allows each element to perform its specific function without compromising the other, resolving the contradiction between sealing integrity and stress resistance.
Solution Approach 2:
The flexible bottom casing element acts as an intermediary between the external environment and the semiconductor platform. It mediates mechanical stress by deforming itself to absorb stress while maintaining the hermetic seal, preventing stress transfer to the semiconductor platform.
2Strength
If a rigid casing is used to protect the semiconductor platform, then structural integrity is improved, but mechanical stress on the platform increases
Solution Approach 1:
Different parts of the casing have different mechanical properties: the top casing element is rigid for structural integrity and sealing, while the bottom casing element is flexible for stress absorption. This local differentiation of material properties resolves the contradiction between overall structural strength and local stress protection.
Solution Approach 2:
The casing combines two materials with different mechanical characteristics: a rigid material (e.g., glass or ceramic) for the top element and a flexible material (e.g., polymer or elastomer) for the bottom element. This composite structure provides both structural integrity and stress resistance.
3Volume of stationary object
If the cavity volume is increased to accommodate larger components, then device functionality is improved, but the structural integrity under mechanical stress deteriorates
Solution Approach 1:
The bottom casing element is designed to be dynamically flexible, allowing it to deform under mechanical stress to maintain structural integrity. This dynamic flexibility enables the cavity to maintain a larger volume while resisting stress-induced damage.
Data Source
AI summary
A sensor device includes a semiconductor platform with a sensor element, a top casing element and a bottom casing element. The top casing element contacts the bottom casing element to form a rigid casing defining a cavity, and the top casing element furthermore contacts the semiconductor platform so that the semiconductor platform is positioned in the cavity and so that a selected region of the semiconductor platform, including the sensor element is contactable by the environment. Furthermore, the top casing element, the bottom casing element, and the selected region of the semiconductor platform are arranged so that the cavity is hermetically sealed.