Issue link: https://iconnect007.uberflip.com/i/1207026
58 SMT007 MAGAZINE I FEBRUARY 2020 Feature Interview by the I-Connect007 Editorial Team Taiyo's Yuya Suzuki, marketing manager for IC packaging materials, talks with Nolan Johnson and Dan Feinberg about the chal- lenges with soldering due to shrinking com- ponents and how Taiyo's R&D work around smaller filler sizes and increased planarity has been preparing them for the future of solder mask. Nolan Johnson: Shrinking components and smaller feature sizes are creating a need for increased precision in all aspects of the com- ponent attachment processes. For Taiyo and its products, what research and development work are you doing to meet these tighter toler- ances that are increasingly showing up in sten- cils and solder paste application? Yuya Suzuki: Screen printing is the major pro- cess for coating or caulking the photoresist. But as the thickness control and tolerance are going to be smaller, some people—especially in the IC packaging area, where they already had a similar issue 10 years ago—lean toward spray coating or other methods. At that point, the viscosity of the photoresist was still com- patible with new coating processes. Another way Taiyo needed to tailor our solder resist ink was by changing the filler size. The thick- ness of the solder resist that can be coatable on top of a circuit board is defined by the filler size, so we are moving toward the smaller filler size, usually tens of micrometers. That is the first step we have taken to accommodate such requirements. Johnson: What effect do these changes pro- duce that can improve yield? Suzuki: By changing the filler size, we can guar- antee that we can accommodate the inner coat- ing capability. It allows the customer to have better thickness tolerance and better reliability for assembly. Johnson: Is the trend toward thinner coatings? Suzuki: Yes. Johnson: Because it's thinner and going to be more planar. Evolving Solder Capabilities for Shrinking Components Yuya Suzuki