Sensor Package Interposer Layout for Stress-Decoupled ASIC Mounting
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Solution Overview
Problem
Integrated sensor devices, particularly pressure sensors, are susceptible to stress and environmental influences, which can degrade their performance and damage the fragile structures, especially since they require direct access to the environment.
Innovation Solution
A sensor package design featuring a carrier with electric conductors, an ASIC device, and a dummy die or interposer with an adhesive layer, where the dummy die provides mechanical decoupling by having smaller lateral dimensions and a coefficient of thermal expansion matched to the ASIC device, enhancing stress and thermal protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ASIC device is directly mounted on the carrier, then the device complexity is reduced, but the sensor element becomes susceptible to stress and environmental influences
Solution Approach 1:
A dummy die is introduced as an intermediary component between the ASIC device and the carrier. This dummy die serves as a stress-absorbing intermediate layer that protects the sensor element from mechanical stress and environmental influences while maintaining the functional integrity of the package structure.
Solution Approach 2:
The package structure is segmented into distinct functional layers: the carrier, the dummy die, and the ASIC device. This segmentation allows each component to perform its specific function - the carrier provides structural support, the dummy die provides stress protection, and the ASIC device performs sensing - thereby resolving the contradiction between reliability and complexity.
2Reliability
If a thick adhesive layer is used between the dummy die and ASIC device, then the stress protection is improved, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
The adhesive layer thickness is specified as a parameter range (at least 80 μm) rather than a fixed value. This parameter change allows for sufficient stress decoupling while accommodating variations in manufacturing processes. The minimum thickness ensures adequate stress protection, while the flexibility in the range maintains manufacturability.
3Reliability
If the ASIC device laterally overhangs the dummy die by at least 100 μm, then the stress resistance is improved, but the device complexity increases
Solution Approach 1:
The ASIC device is designed with asymmetric lateral dimensions relative to the dummy die, specifically overhanging by at least 100 μm on at least one side. This asymmetric configuration provides enhanced stress resistance and mechanical stability while maintaining a relatively simple overall package structure, resolving the contradiction between reliability and complexity.
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 effectively decouples the ASIC device from the carrier, reducing the impact of external forces and thermal stress on the sensor element, thereby enhancing the mechanical and thermal stability of the sensor package and improving its performance.
Implementation Method 1
an adhesive layer comprising silicone is arranged between the dummy die or interposer and the ASIC device
Implementation Method 2
a coefficient of thermal expansion matched to the ASIC device, enhancing stress resistance and thermal stability
Data Source
AI summary
A sensor package and a method for producing a sensor package are disclosed. In an embodiment a method for producing a sensor package includes providing a carrier including electric conductors, fastening a dummy die or interposer to the carrier, providing an ASIC device including an integrated sensor element and fastening the ASIC device to the dummy die or interposer.