One Die Reaching the Market as Component Module and Probe
Selecting die packaging forms requires matching land pattern mechanical stress, bus wiring distance, and calibration stability against landed unit economics.
Epoxy Shrinkage
Volumetric Reduction
Polymeric curing processes generate a decrease in volume as liquid resins transition into solid crosslinked networks. This behavior, known as epoxy shrinkage, occurs because the covalent bonds formed during polymerization are shorter than the intermolecular distances between unreacted monomers. The reduction in volume usually ranges from one to five percent depending on the formulation.
In precision sensor assemblies, this change can pull components out of alignment and create permanent mechanical offsets that damage delicate electrical connections.
Stress Development
Constrained materials cannot contract freely during the curing phase. In these situations, epoxy shrinkage generates internal stresses that can cause microcracks or adhesive failure at the interface between the sensor element and the housing. These mechanical stresses are exacerbated when the curing temperature is high, as the material also undergoes thermal contraction during cooling.
Sensing Distortion
Precision measurement devices are highly sensitive to external mechanical loads. When epoxy shrinkage occurs directly on a silicon strain gauge or a MEMS die, it applies an unintended bias that appears as a zero point drift or calibration error. This mechanical shift remains permanent unless the material is fully stabilized or recalibrated.
Mitigation Technique
Filler materials such as silica or alumina are mixed into the resin to reduce the proportion of active polymer. By lowering the resin fraction, epoxy shrinkage is reduced and the thermal conductivity of the compound is improved. The addition of these inorganic particles helps maintain the geometry of the sensor package throughout its operating life.