1. Product Overview
LOCTITE® ECCOBOND UF 9000AE is a high-performance epoxy underfill encapsulant specifically formulated for large die flip chip BGA and Cu pillar package applications. It offers low coefficient of thermal expansion (CTE), optimized viscosity, low resin bleed-out, and strong self-filleting behavior. Once cured, it provides a rigid, protective seal that enhances solder joint durability, thereby improving electrical, thermal, and moisture reliability.
2. Applications
This product is used as a semiconductor underfill and electronic encapsulant. Its main applications include flip chip BGA and Cu pillar packaging, where it ensures fast capillary flow, reliable sealing, and effective stress dissipation in demanding Pb-free, low-k reflow conditions.
3. Typical Properties
| Property |
Uncured |
Cured |
| Appearance |
Black liquid |
Rigid solid (self-filleting) |
| Viscosity (25°C, 5 rpm), mPa·s |
9,082 |
— |
| Thixotropic index (0.5/5 rpm) |
0.85 |
— |
| Specific gravity @ 25°C |
1.71 |
— |
| Pot life @ 25°C |
24 hours |
— |
| Shelf life @ -40°C |
365 days |
— |
| Cure schedule |
15 min ramp to 100°C, hold 90 min; ramp to 165°C, hold 2h |
Fully cured |
| Glass transition temperature (Tg), °C |
— |
111–112 |
| CTE, ppm/°C |
— |
23 (below Tg), 85 (above Tg) |
| Storage modulus, N/mm² |
— |
13,500 @25°C; 136 @250°C |
This balance of low CTE, high modulus, and robust reflow stability makes UF 9000AE highly suited for advanced electronic packaging reliability.