Electrodeless copper deposits are typically applied before conventional electroplating in order to provide a conductive base on plastics or other nonconductors. Major markets for electrodeless copper include automotive parts, appliance components, printed wiring boards, molded interconnect devices, plastic composite connectors, multichip modules and EMI/RFI shielding of electronic devices.

Components of the electrodeless bath include an aqueous solution of copper ions, reducing agents, complexing agents and bath stabilizers operating in a specific ion concentration, temperature and pH range. The typical reducing agent used is formaldehyde and the typical complexing agent is Rochelle Salt.

Control Strategy

The consumption of critical components in the bath occurs in direct proportion to the consumption of copper. Complexing agents and stabilizer levels occasionally need independent control, although on-line analysis of dissolved copper is sufficient for most applications.

Apparatus