The continuous technique is used in combination with automated analytical devices such as chemical sensors. They are capable of continuously recognizing concentrations of chemical constituents in liquids or gases and converting this information in real-time to an electrical or optical signal. The focus of this project is to design and test suitable chemical sensors that will help in the processing of chemical signals obtained from circuit card manufacturing. These sensors must be capable of being integrated into other devices that can exercise real-time feedback required in the electroless plating bath technologies used in the fabrication of circuit boards and cards found in electronic devices. In the fabrication of most circuit cards and boards, electrolytic or electroless methodologies are used for both the bulk circuitization and surface finishing.
Electrolytic processes utilize an external current source for metal ion reduction.
On the other hand, electroless methods involve the use of chemical reducing agents to drive the heterogeneous reduction of metal ions or complexes. Compared to electrolytic plating technique, electroless-plating principle is highly attractive because of its simplicity of operation, which requires no external source of current or elaborate equipment. The use of electroless deposition takes care of the problems associated with dendrite formation and uneven deposits associated with electrolytic deposition in which non-uniform current densities occur. IBM, a leading computer manufacturer, currently employs a proprietary electroless Au-plating process for these applications and for ceramic modules. Electroless gold deposition process requires frequent and accurate monitoring of numerous chemical parameters, including gold, reducer and stabilizer concentrations.