Multilayer HDI PCB with Micro BGA Assembled

This PCBA is for a high-tech innovation product smart boots. PCB is 6 layer HDI PCB with blind holes,very small size and irregular shape. There are total 9 BGA on this board, all of them are mini BGA. The minimum distance between ball centre  is 0.4mm,minimum distance between ball edge is 0.15mm. There are two BGA with 4 balls,which needs rich experience and sophisticated SMT equipment to do this assembly work. 

To ensure the assembly quality , X-RAY test is necessary. And the result is very good, all of those BGA are asembled perfectly .