Die Attach Membrane for Pressure Sensor Packaging
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Solution Overview
Problem
Current pressure sensor packaging isolates the sensing element from the ambient environment, leading to reduced accuracy and potential failure in corrosive conditions due to material incompatibility.
Innovation Solution
A circuit element package with a substrate, die pad, and access hole, using a die attach membrane to expose the circuit element die to the environment while protecting it from damage, utilizing a porous membrane layer made of PTFE or similar materials to allow signal transmission while blocking destructive agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensing element is isolated from the ambient environment using conventional packaging, then the sensing element is protected from environmental damage, but the measurement accuracy is reduced
Solution Approach 1:
The patent uses a thin film substrate that is permeable to the measurand (pressure, temperature, or other environmental parameters) while providing mechanical support and protection. This thin film allows the sensing element to effectively interact with the ambient environment through the substrate, resolving the contradiction between protection and measurement accuracy.
Solution Approach 2:
The substrate acts as an intermediary between the sensing element and the ambient environment. It is designed to be transparent or permeable to the specific measurand while providing physical support and environmental filtering, allowing accurate measurement without direct exposure of the sensing element to harmful environmental factors.
2Measurement precision
If the sensing element is exposed to the ambient environment for accurate sensing, then the measurement accuracy is improved, but the sensing element is vulnerable to environmental damage
Solution Approach 1:
The thin film substrate provides a protective barrier that is simultaneously permeable to the measurand. This allows the sensing element to be protected from environmental damage while maintaining accurate sensing capability through the film structure.
Solution Approach 2:
The substrate is constructed from composite materials or multi-layer structures that provide both mechanical protection and permeability to the specific measurand. The composite structure allows selective transmission of environmental parameters while blocking harmful substances.
3Strength
If conventional packaging materials are used to protect the sensing element, then the structural integrity is maintained, but the material may not be resistant to corrosive environments
Solution Approach 1:
The substrate uses composite material structures that combine mechanical strength with chemical resistance. The composite construction provides both structural integrity for mounting the sensing element and resistance to corrosive environmental conditions.
Solution Approach 2:
The substrate material properties are specifically selected and engineered to change or adjust parameters such as permeability, chemical resistance, and mechanical strength to match the specific measurement requirements and environmental conditions.
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
Enables accurate sensing by exposing the circuit element die to the ambient environment while protecting it from environmental damage, ensuring reliable operation in corrosive conditions.
Implementation Method 1
The die attach membrane 22 is comprised of a porous membrane layer 24. The porous membrane layer 24 has several hundred million micro pores per square centimeter.
Implementation Method 2
The porous membrane layer 24 allows the transmission of pressure signals into the sensor port 20, while retarding or eliminating the transmission of destructive environmental agents.
Implementation Method 3
In accordance with one embodiment of the present invention, the porous membrane layer 24 is made from Poly-Tetra-Fluoro-Ethylene commonly referred to as PTFE, or other similar material from this fluoroplastic family.
Data Source
AI summary
A circuit element package has a substrate having a plurality of electrically conductive patterns, a die pad, and an access hole formed through the die pad and substrate. A plurality of leads is coupled to the substrate. A circuit element die is attached to the die pad wherein a first sensor port is positioned over the access hole. A die attach membrane is provided for attaching the circuit element die to the die pad. The die attach membrane allows the circuit element die to sense ambient while protecting the circuit element die from environmental damage. An encapsulant is used for covering portions of the circuit element die.