LCP Substrate Hermetic Sealing via Electrical Trace Joule Heating
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Solution Overview
Problem
Electronic devices, such as biosensors and biostimulators, are susceptible to damage from contaminants like bodily fluids, and existing packaging methods fail to provide a reliable hermetic seal, especially in environments like the human body where contamination risk is high.
Innovation Solution
The method involves creating a hermetic seal around electronic components using a liquid crystal polymer (LCP) substrate, where an electrical trace is used as a microheater to melt and fuse the LCP substrate to the substrate, eliminating the need for additional bonding agents and minimizing exposure to high temperatures that could damage the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packaging methods are used to seal electronic devices, then manufacturing simplicity is maintained, but hermetic seal reliability is insufficient especially in high contamination environments
Solution Approach 1:
The patent combines the sealing function and cutting function into a single electrical trace structure. The same trace that creates the hermetic seal by melting the LCP substrate also serves as the cutting element to separate individual devices during singulation, eliminating the need for separate packaging and singulation processes
Solution Approach 2:
The patent utilizes phase change of the LCP substrate material by controlling temperature parameters. The electrical trace heats the LCP substrate to its melting point to create the hermetic seal, then continues heating to cut through the substrate for device singulation. This parameter-based approach transforms the material state to achieve multiple functions
2Reliability
If high temperature is applied to create hermetic seal, then seal quality improves, but electronic components may be damaged by excessive heat
Solution Approach 1:
The electrical trace provides localized heating only at specific positions where the hermetic seal is needed, rather than heating the entire device uniformly. This allows the LCP substrate to melt and fuse at the trace locations creating reliable seals while the rest of the electronic components remain at safe temperatures
Solution Approach 2:
The LCP substrate acts as an intermediary material between the electrical trace and the electronic components. The trace melts and fuses the LCP substrate to create the seal, and the LCP substrate itself provides the hermetic barrier, preventing direct heat transfer from the trace to the sensitive electronic components
3Reliability
If additional bonding agents are used to seal devices, then sealing capability is enhanced, but manufacturing steps and cost increase
Solution Approach 1:
The electrical trace itself performs the sealing function by melting and fusing the LCP substrate through resistive heating. The trace serves as both the heating element and the structural component that creates the hermetic seal, eliminating the need for separate bonding agents or additional sealing steps in the manufacturing process
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
This technique provides a high-quality hermetic seal that protects electronic devices from contaminants while avoiding damage from excessive heat, and also allows for the singulation of individual devices from a common substrate using the same microheater approach, reducing debris and manufacturing costs.
Implementation Method 1
electrically coupling an electrical power source to the electrical trace to generate a current in the electrical trace; melting the second substrate using heat generated by the current through the electrical trace
Implementation Method 2
electrically coupling an electrical power source to the electrical trace to generate a current in the electrical trace; melting the first substrate using heat generated by the current through the electrical trace to singulate each electronic device
Data Source
AI summary
One disclosed method includes defining an electrical trace on a first substrate; physically coupling an electronic component to the first substrate, wherein a portion of the electrical trace completely encircles the electronic component; overlaying a second substrate onto the first substrate, the overlaying causing the second substrate to completely cover the portion of the electrical trace and the electronic component; electrically coupling an electrical power source to the electrical trace to generate a current in the electrical trace; melting the second substrate using heat generated by the current through the electrical trace; and fusing the second substrate to the first substrate to generate a hermetic seal around the electronic component.