The drilled panel now requires its surface tracks defining and the barrels of the via holes plated to form a connection to the buried inner layers and the tracks on the other outer surface.
The drilled panels have their surfaces cleaned and are then passed through a process to remove any smeared resin from the drilled holes which could prevent inner layer connections from being satisfactorily made. The non-conductive hole walls must then be metalised. We use a well established and thoroughly reliable automatically controlled electroless copper plating process. This coats hole walls and the whole panel surface with a thin layer of conductive copper. Back light tests and rate panels are used to check the coverage and thickness of copper. It is essential that this foundation plating layer has the highest integrity for it is upon this layer that the whole of the circuit interconnect relies.
The metalised panels are then returned to the clean room where they are laminated with photo polymer film on an auto laminating machine dedicated to outer layers,. Using precision photo tools mounted in glass to glass printing frames the cores are exposed with the appropriate image.
The exposed panels are then automatically loaded to a dedicated conveyorised developing line. After processing they are transferred to the plating department.
The Electrolytic plating line deposits copper utilising reverse pulse plate rectification for closely controlled thickness distribution and the plating of high aspect ratio holes. The last stage of the plating process is to deposit a thin layer of tin over the plated surfaces. This tin layer protects the plated copper during the etching process. The final step is to remove this protective tin layer. The end product is a working circuit with its copper surface unprotected from atmospheric contamination.
+44 (0)1606 861155
Wharton Ind Estate, Nat Lane, Winsford, Cheshire, CW7 3BS
