Microstructural, Morphological and Electrical Studies of a Unique Dry Plasma Metal Deposition for Printed Circuit Boards (PCBs)EPA Grant Number: R826119
Title: Microstructural, Morphological and Electrical Studies of a Unique Dry Plasma Metal Deposition for Printed Circuit Boards (PCBs)
Investigators: Sampath, W. S. , Barth, Kurt
Institution: Colorado State University
EPA Project Officer: Richards, April
Project Period: September 1, 1997 through August 31, 2000 (Extended to September 30, 2000)
Project Amount: $200,001
RFA: Technology for a Sustainable Environment (1997) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
Description:We propose to conduct basic research for applying dry plasma metal film deposition to Printed Circuit Board (PCB)manufacturing, to reduce the pollution intensiveness of the industry through elimination of liquid waste treatment and reduction of solid waste. A unique research system incorporating continuous air to vacuum to air (AVA) transport of substrates and magnetron sputtering for film deposition will be used to gain an understanding of metal depositions for PCBs. The film thickness for copper is substantially larger than the film thicknesses typically deposited with magnetron sputtering. The effect of this thickness on film properties and residual stress will be studied. Most thin film studies with magnetron sputtering are done on non polymeric substrates. So, a fundamental understanding of large film thicknesses deposited on polymeric composite substrates need to be developed. This understanding is needed for applying the magnetron sputtering technology to the PCB industry.
In other applications, high substrate temperatures are used for improving adhesion and reducing porosity. The heat resistance of epoxy resins is less than 260 degrees C so the maximum allowable temperatures for PCB substrates must be kept relatively low. However, the presence of the plasma will increase the surface mobility of the deposited atoms and will densify the films; this effect needs to be characterized.
Completion of the effort outlined above will answer the basic research objectives and provide the basic insight needed to implement dry plasma metal deposition as a replacement for wet chemical processing in the PCB industry. This research could be the catalyst for industry to move forward and implement dry plating technology. The methodology of statistical design of experiments (SDE) will be used in this study. The properties (adhesion, porosity resistivity, and contact resistance) of films of copper, nickel and gold made by AVA dry plasma deposition will be understood.
Research will be completed to gain an understanding of the process conditions that lead to acceptable film properties for the PCB manufacturing.