Increasingly fine pitch component patterns on PCBs, and ever-smaller passive components such as 03015’s continue to narrow the process window for PCB assemblers. The drive toward ever-finer pitches is driven by a number of factors, particularly miniaturization in mobile devices such as Smartphones, where consumers are demanding greater functionality in compact, hand-held devices. As a result, material handling and component placement becomes more difficult, and solder paste printing is especially impacted.

Thinner stencils, smaller particle size solder paste, and smaller apertures, whereby even aperture shape becomes a factor in volume fill, test the limits of the successful printing process. Achieving sufficient or acceptable paste volume fill of fine-feature apertures has become an issue. Printing machine technology continues to advance to meet the finepitch challenge, with greater precision and motion control, closed-loop feedback systems, enclosed media printing, enhanced software tools and machine vision assists, and many other developments and innovations designed to enable successful and repeatable fine pitch solder paste printing for high-density SMT assemblies.

This paper details those developments, and illustrates how they are contributing to process improvement through comparative test results.