Prony Series Viscoelastic Modeling for Sensor Packaging Stress Relaxation Analysis
Prony series modeling converts polymer relaxation data into actionable sensor zero-drift predictions, isolating packaging strain from true physical signals.
Liquid Encapsulant
Component Insulation
Polymeric potting compounds provide a protective barrier for electronic assemblies against environmental and mechanical hazards. A common choice is the liquid encapsulant, which is dispensed in a fluid state to fill the gaps around delicate wires and silicon dies. Hardening of this material prevents moisture ingress or electrical leakage.
It is a standard solution for automotive sensors or aerospace circuitry.
Flow Property
Viscosity and surface tension govern how effectively a fluid fills a confined space. When applying a liquid encapsulant, the material must flow under every wire bond without creating air pockets or voids. Vacuum degassing often precedes the dispensing process to remove dissolved gases that could cause bubbles during the heating phase.
If the flow is too fast, it may spill over the intended boundaries of the circuit board. Precise control of the dispensing needle height ensures a uniform coating thickness.
Thermal Protection
Expansion coefficients of the protective layer must align with the underlying substrate to prevent cracking. The liquid encapsulant acts as a heat sink or a thermal buffer depending on its chemical composition and filler content. During temperature cycles, the stress at the interface between the silicon and the resin can lead to delamination.
Fillers such as silica or alumina are added to the resin to adjust the thermal expansion rate.
Curing Requirement
Chemical crosslinking transforms the fluid into a solid matrix through the application of heat or ultraviolet light. The performance of the liquid encapsulant depends on the completeness of this cure cycle. If the material remains partially liquid, it will not provide the necessary mechanical support or chemical resistance.
Lab tests verify the hardness and the glass transition temperature of the cured resin.