Shanghai Huitian New Material Co., Ltd ultimo caso della società circa Huitian 6631H Underfill Adhesive: Solving CSP/BGA Solder Joint Fatigue in Mass-Produced Wearable Devices

Solution: Huitian 6631H Single-Component Underfill Epoxy

After evaluating six underfill candidates from both international and domestic suppliers, the engineering team selected Huitian 6631H, a single-component, heat-curing epoxy underfill specifically formulated for CSP/BGA protection and FPC (Flexible Printed Circuit) reinforcement. The decision was driven by four key performance attributes:

Process Integration

6631H was deployed across three production lines, targeting:

• Main Processor BGA (0.35mm pitch): Underfill dispensed along two adjacent edges post-reflow; complete capillary fill verified by X-ray inspection
• PMIC CSP (0.3mm pitch): Single-edge dispensing with automated vision-guided needle positioning
• FPC Connector Reinforcement: Applied to flex-to-board interconnects subjected to repeated assembly/disassembly during battery testing

The curing step was integrated into the existing inline oven profile at 130°C for 10 minutes, requiring zero additional floor space or cycle-time adjustment.

Results

The OEM's VP of Manufacturing Engineering noted: "6631H solved the fundamental contradiction between reliability and manufacturability that we struggled with for two product generations. The fast flow and cure profile meant we could add underfill protection without slowing the line, and the reworkability eliminated the fear of scrapping expensive assembled boards."