2004 年 7 巻 1 号 p. 62-66
The influence of powder size in solder paste on the solder volume applied by paste printing has been examined. The applied solder volume increased with decreasing the average diameter of solder powder which are contained in the solder paste. The solder paste with fine solder powder easily caused a solder bridging failure between the electrodes for a fine pitch QFP after reflow soldering. The measurement value of the applied solder volume was good accordance with the approximate half of the calculated volume using the close-packed model in which the powder with the average diameter is close-packed in the opening space of the stencil.