Underfill Epoxy
CAS Number: 25068-38-6
Underfill epoxy is a capillary or no-flow epoxy encapsulant dispensed beneath flip-chip, BGA, and CSP packages to redistribute thermal and mechanical stress across solder joints, dramatically improving fatigue life. It fills the gap between the chip and the substrate by capillary action and cures to a rigid, hermetically sealed structure. Critical for high-reliability mobile, server, and automotive applications.
Technical Specifications
| Tg | 120–160°C |
| CTE | 20–35 ppm/°C |
| filler | Silica filler, 60–70 wt% |
| viscosity | 3,000–20,000 cP at 25°C |
| appearance | Black or clear liquid |
| cureCondition | 150°C / 30 min (typical) |
Applications
- Flip-chip BGA underfilling
- CSP and wafer-level package reinforcement
- Automotive-grade IC reliability enhancement
- Server and HPC package stabilization
- Fine-pitch solder joint fatigue life improvement
Key Features
- Dramatically extends flip-chip solder joint fatigue life
- Low viscosity for fast capillary flow
- Low CTE matched to PCB substrate
- Meets AEC-Q100 automotive reliability standards