Semiconductor Strain Sensor Packaging for Accurate Strain Transfer
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Solution Overview
Problem
Thicker strain gauges are less responsive, suffer from inaccurate measurements due to gaps or uneven contact, and have higher mass and inertia, leading to slower response times and measurement drift.
Innovation Solution
Semiconductor-based strain gauges with flexible and thin packaging materials, featuring a carrier layer and enclosure made of low Young's modulus materials like polyimide or silicone, and metal interconnects that allow stretching and compressing, along with mechanical decoupling to enhance sensitivity and response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thicker packaging materials are used, then protection and structural stability are improved, but sensitivity and response time deteriorate
Solution Approach 1:
The patent employs flexible packaging materials with low Young's modulus values (10 kPa to 3 GPa) that are significantly thinner than traditional packaging. These thin-film materials provide adequate protection while maintaining flexibility to accurately transmit strain to the semiconductor die, eliminating the trade-off between protection and sensitivity.
Solution Approach 2:
The patent changes the mechanical parameters of the packaging material by selecting materials with specific Young's modulus ranges (10 kPa to 3 GPa) that match the stiffness of the semiconductor die. This parameter matching ensures optimal strain transmission while maintaining structural integrity.
2Strength
If thicker strain gauges are used, then mechanical strength is improved, but response time and sensitivity deteriorate
Solution Approach 1:
The patent uses thin-film packaging materials that are much thinner than traditional strain gauge packaging. This reduced thickness minimizes the mass and inertia of the packaging structure, enabling faster response to strain changes while maintaining sufficient mechanical strength through the low-but-sufficient Young's modulus materials.
Solution Approach 2:
The patent employs composite material structures combining the semiconductor die with flexible packaging materials having specific mechanical properties. This composite approach optimizes both strength and response time by selecting materials that work synergistically.
3Strength
If rigid packaging materials are used, then protection is improved, but strain transmission accuracy deteriorates
Solution Approach 1:
The patent replaces rigid packaging materials with flexible thin-film materials that have low Young's modulus values. These flexible materials provide adequate protection while maintaining the ability to accurately transmit strain to the semiconductor die without the gaps or uneven contact that occur with rigid materials.
Solution Approach 2:
The patent changes the stiffness parameter of the packaging material by selecting materials with Young's modulus values between 10 kPa to 3 GPa, which are much softer than traditional rigid packaging. This parameter change enables accurate strain transmission while maintaining protective functionality.
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 solution provides high sensitivity, accurate strain measurements with reduced hysteresis and faster response times by using flexible packaging materials and mechanical decoupling, improving the strain gauge's performance.
Implementation Method 1
A strain gauge may operate based on the principle that electrical resistance of a material within the strain gauge changes as the material is stretched or compressed
Data Source
AI summary
A packaged integrated circuit includes a first layer having opposing first and second surfaces, first pads on the first surface, second pads on the second surface, and metal interconnects electrically coupled between the first and second pads. A semiconductor die has opposing first and second sides. The first side of the semiconductor die is mounted on the second surface of the first layer. The first side of the semiconductor die has metal interconnects coupled to the second pads. An enclosure is on the second surface of the first layer. The enclosure wraps around at least part of the semiconductor die. The enclosure has an opening through which at least part of the second side of the semiconductor die is exposed.