MEMS Sensor Package Isolation Structure for Thermal and Vibration Stability
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Solution Overview
Problem
Existing MEMS sensor packaging technologies are costly and unreliable, failing to adequately protect microstructure sense elements from environmental stresses that degrade motion measurement accuracy.
Innovation Solution
A microelectronics package design featuring an isolation structure with an elastomer pad, connector assembly, and hermetically-sealed cavity to minimize errors from temperature, shock, and vibration, using standard IC packaging techniques with flexible cables and thermal conductive materials for improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging schemes are used to protect MEMS sense elements, then protection from environmental influences is achieved, but cost increases and reliability is not ensured
Solution Approach 1:
The packaging structure is divided into distinct functional segments: a rigid base providing structural support and electrical connections, a flexible intermediate layer providing vibration isolation and stress relief, and a hermetic seal providing environmental protection. This segmentation allows each component to be optimized for its specific function while simplifying the overall assembly process.
Solution Approach 2:
The packaging employs composite construction combining rigid materials (metal or ceramic base) with flexible materials (elastomeric intermediate layer) to create a structure that simultaneously provides mechanical strength, vibration isolation, and hermetic sealing. This composite approach achieves high reliability without requiring complex single-material solutions.
2Reliability
If high-force hermetic sealing is applied to protect MEMS packages, then sealing reliability is improved, but stress on internal components increases
Solution Approach 1:
The elastomeric intermediate layer is positioned between the rigid base and the hermetic seal to provide beforehand cushioning. This flexible layer absorbs and distributes the high forces applied during hermetic sealing, preventing these forces from being transmitted directly to the sensitive MEMS components while still achieving reliable sealing.
Solution Approach 2:
The elastomeric intermediate layer serves as an intermediary element between the hermetic sealing force and the internal components. It mediates the interaction by providing a compliant interface that allows the seal to be applied with high force while isolating the internal components from that stress.
3Strength
If rigid packaging structures are used to protect from vibration, then mechanical strength is improved, but vibration isolation performance deteriorates
Solution Approach 1:
Different parts of the packaging structure have different mechanical properties optimized for their local function: the base and seal provide rigid structural strength, while the intermediate layer provides flexible vibration isolation. This local differentiation of mechanical properties allows the overall structure to simultaneously achieve high strength and good vibration isolation.
Solution Approach 2:
The elastomeric intermediate layer functions as a flexible element within the packaging structure, providing vibration isolation through its compliance while being sandwiched between rigid components that provide overall structural strength. This flexible-rigid-flexible arrangement achieves both mechanical strength and vibration protection.
4Temperature
If thermal conduction is enhanced to improve heat dissipation, then temperature stability is improved, but thermal stress on components increases
Solution Approach 1:
The elastomeric intermediate layer serves as a thermal mediator between the rigid base and the internal components. It provides a controlled thermal interface that allows heat dissipation while accommodating thermal expansion differences, thereby reducing thermal stress on the components.
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
The design enhances performance by isolating internal components from external forces, providing thermal and vibration stability, and simplifying assembly while maintaining electrical connectivity.
Implementation Method 1
an elastomer pad for vibration damping
Implementation Method 2
An elastomer pad is on the first portion and a sub-assembly is on the elastomer pad
Implementation Method 3
The attached lid forms a hermetically-sealed cavity defined by an upper surface of the first portion, the connector assembly, and an inner surface of the lid
Data Source
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AI summary
A semiconductor package with design features, including an isolation structure for internal components and a flexible electrical connection, that minimizes errors due to environmental temperature, shock, and vibration effects. The semiconductor package may include a base having a first portion surrounded by a second portion. A connector assembly may be attached to the first portion. The connector assembly may extend through an opening in the base. A lid attached may be attached to, at least, the second portion. The attached lid may form a hermetically-sealed cavity defined by an upper surface of the first portion, the connector assembly, and an inner surface of the lid. An elastomer pad may be on the first portion and a sub-assembly may be on the elastomer pad. A flexible electrical connection may be formed between the connector assembly and the sub-assembly.