Why Sensitive MEMS Chips Are Better Protected by Low-Stress Fluorosilicone Gel
Packaging materials for MEMS pressure sensors must satisfy multiple requirements simultaneously: low stress, moisture resistance, electrical insulation, protection for gold wires and solder joints, and medium resistance in practical environments. Since MEMS operates relying on tiny mechanical structures, excessive material modulus, curing shrinkage and thermal expansion stress may cause zero drift or signal variation. ELAPLUS FSGEL 3200C is a one-component thixotropic fluorosilicone gel, which is suitable for flexible, low-stress and medium-resistant protection of MEMS chips, gold wires and sensitive electronic areas. It is NOT designed for primary structural bonding of magnetic steel, housings and other load-bearing structures. When packaging sensitive chips such as MEMS pressure sensors and micro-pressure sensors, the core principle for material selection is not “the harder and firmer, the better”. Instead, materials shall provide moisture-proof, anti-corrosion, oil/gas and chemical medium resistance, gold wire and solder joint protection, while minimizing mechanical stress exerted on chips by packaging materials. That is why for certain MEMS sensor protection scenarios, soft, low-stress fluorosilicone gel is preferable compared with traditional high-modulus rigid potting materials. Take ELAPLUS FSGEL 3200C one-component thixotropic fluorosilicone gel as an example. Its main function in application is not to fix the housing structure, but to form a flexible protective layer over MEMS chips, gold wires, solder joints and sensitive electronic regions. In short: The real challenge of MEMS packaging is not merely “covering the chip”, but protecting it without interfering with its sensing function. I. Why Are MEMS Sensors More “Vulnerable to Adhesives” Than Ordinary PCBs? For ordinary PCB potting, we usually expect materials to fix components, resist moisture and water, provide insulation and resist vibration. However, MEMS devices have one special requirement: They work based on micro-deformation. MEMS stands for Micro-Electro-Mechanical Systems. Take MEMS pressure sensors as an example. Pressure acts on the internal sensitive structure of…
