Masters Abstracts (1993)

LEE, TAE-HAN
(December 1993), Northeastern University, Boston, MA

Email: tae@coe.neu.edu

Process Study in Ultrafine Pitch Hot Bar Reflow Soldering

Surface mount components trends in the last decade indicate that component densities and lead counts have increased while the component lead pitch has decreased. New soldering techniques are being identified and used in order to overcome the complications encountered in the soldering of ultrafine pitch components. One such new reflow soldering method is hot bar bonding. The introduction of Tape Automated Bonding (TAB) devices has enhanced the need for the hot bar reflow techniques in Printed Circuit Board (PCB) assembly.

The objective of this research was to study the influence of process related factors on solder joint formation when hot bar reflow soldering is used. The factors considered included the component types and lead configuration, flux types, flux application methods, different substrate material thickness with different pad width, solder pad plating thickness, aging, thermode temperature profile, component lead plating material, and thermode and spindle force.

Prior to actual experimentation, the UIC 4682B fine pitch bonder was characterized. The objective of the characterization was to identify the performance attributes of the machine variables for subsequent experimentation in hot bar bonding. The machine related factors characterized in this research included the thermode force, force of the component pick- up/placement spindle, and the compliance characteristics of the thermode suspension system. The thermal performance of various thermodes was also studied.