Sensor Package Shielding Member Thermal Expansion
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Solution Overview
Problem
Conventional sensor package structures with large sensor dies suffer from warpage and stress issues due to temperature changes, leading to poor reliability.
Innovation Solution
A sensor package structure incorporating a substrate, a sensing member, a shielding member with a low coefficient of thermal expansion, and an encapsulating compound, which forms an enclosed accommodating space around the sensing zone to reduce thermal stress and enhance structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor die size is increased to improve sensing performance, then the sensing quality is improved, but the warpage and stress increase due to temperature changes
Solution Approach 1:
The patent changes the physical parameters of the package structure by introducing a shielding member with specific geometric features (ring-shaped supporting portion) and material properties (low coefficient of thermal expansion). This modifies the thermal and mechanical parameters of the overall structure to reduce warpage and stress while maintaining large sensor die size for high sensing quality.
Solution Approach 2:
The patent employs a composite structure combining the sensor die, substrate, encapsulating compound, and shielding member with low coefficient of thermal expansion. This composite approach allows the structure to withstand thermal stresses better, maintaining reliability while supporting large sensor dies for improved sensing performance.
2Measurement precision
If the sensor die size is increased to improve sensing performance, then the sensing quality is improved, but the structural strength decreases due to larger package size
Solution Approach 1:
The shielding member is segmented into a ring-shaped supporting portion that distributes mechanical loads across multiple contact points with the substrate. This segmentation approach strengthens the overall structure without requiring a complete redesign of the entire package, allowing large sensor dies to be supported with improved structural integrity.
Solution Approach 2:
The patent adds a vertical dimension to structural support by positioning the ring-shaped supporting portion at a specific height above the substrate. This three-dimensional arrangement provides additional structural reinforcement without increasing the horizontal footprint, maintaining compact packaging while improving strength.
3Measurement precision
If a conventional sensor package structure is used with large sensor die, then the sensing performance is improved, but the warpage increases due to temperature changes
Solution Approach 1:
The patent directly addresses thermal expansion effects by selecting a shielding member material with low coefficient of thermal expansion. This material choice compensates for thermal expansion mismatches between different components (sensor die, substrate, encapsulant), significantly reducing warpage caused by temperature variations while maintaining large sensor die for high performance.
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 proposed structure effectively mitigates warpage and stress, thereby improving the reliability of the sensor package by providing better structural strength and thermal stability.
Implementation Method 1
The supporting portion having a coefficient of thermal expansion less than 10 ppm/° C. is fixed on the carrying zone of the sensing member
Data Source
AI summary
A sensor package structure includes a substrate, a sensing member, a shielding member, a metallic wire, and an encapsulating compound. The substrate includes a die bonding zone and a wiring zone. The sensing member is mounted on the die bonding zone and includes a sensing zone, a carrying zone arranged around the sensing zone, and a connecting zone arranged outside of the carrying zone. The shielding member includes a translucent covering portion and a supporting portion connected to a peripheral portion of the covering portion. The supporting portion having a coefficient of thermal expansion less than 10 ppm/° C. is fixed on the carrying zone. The metallic wire connects the wiring zone and the connecting zone. The encapsulating compound is disposed on the wiring zone and covers a peripheral side of the sensing member, the connecting zone, and a peripheral side of the shielding member.