A Novel Horizontal Copper Pattern Plating System with High Throughput

Horizontal copper plating processes have been used in high volume production to produce PCB's for MLB, Flex-rigid, IC substrates and HDI applications. As the lines and spaces (L/S) requirements have become more and more challenging over the years, panel plating technology has hit the barrier in the range of L/S 35/35 μm in combination with a request for rectangular shape of the traces. Pattern plating mode and the use of (a)mSAP processes becomes a must to achieve L/S in the range of 20/20 μm. So far these kind of applications were difficult to be produced in standard horizontal equipment because of following aspects:1
^st
. The panel thickness for these applications is usually in the lower range less than 60 + 2 × 9 μm Copper clad and it was difficult to transport these thin panels in horizontal mode in all cases.2
^nd
. The solution flow arrangement is not sufficient for thin panel transportation and pattern plating.3
^rd
. The former horizontal copper electrolytes have not been designed for pattern plating.4
^th
. Dry film damages in pattern plating mode.