2 layer FPC loading connector with only 0.16mm pitch

Last week,we made the FPC--Flex Printed Circuit Boards. The PCB is here.

It is 2 layer, min trace/space 0.1/0.1mm,stiffener at top side with 0.8mm.

The connector pitch is so small which it is only 0.16mm,the pad width is only 0.23mm.

The big problem is customer missed to add fidicual mask on the board ,and the FPC is single unit. There is no aligement position.  And due to the fine pitch ,it is so easy to get short circuits. We made twice stencils,the first time,made as usual with 0.1mm thickness. TOO thick and too paste aplied on PCB . so we have to change the cuts ,make them smaller ,and change the stencil thickness to 0.08mm.  We aligned with the silkscreen texts dot,as no fiducial marks . After several PCB aplied, all goes well . they are very good. 

We have to adjust each boards when applying paste and loading too. In the future, there must be fiducial marks on boards.

Luckily, there are only 20 units to load,we apply paste and loaded components by auto machine ,and inspected all boards. all is good. 

Although this job cost us much more time than we expected,but we are happy and proud that we can help customers for such prototypes which others are unable to do .