Application of statistical tools and methods for high density substrate process development [printed circuit board fabrication]

Statistical tools and methodologies were used in a process development application to develop the alignment process for high density substrate fabrication. Improved. capability of the alignment process was realized by reducing variation of the scale alignment mode. First, the data range of interest was determined for scale alignment mode. Then, over the determined data range of interest, the measurement capabilities of the measurement systems used in the work were determined by MSA (measurement system analysis). By use of a DOE (design of experiment), the measurement systems were determined to give significantly different measurements, indicating algorithms were necessary to translate available data from one measurement system to the reference measurement system for reducing scaling variation in the alignment process. The available data was found to highly correlate to the reference measurement system. Subsequently, using regression modeling techniques, algorithms were developed that translated available data to scale factors for compensation of the placement of through-vias and outermetal in relation to the microvias, the identified limiting factor to alignment capability.