Solder Mask: You’ve Come a Long Way, Baby!

Estimated reading time: 2 minutes

For this issue, our editing team met with Electra Polymers’ Shaun Tibbals and Antony Earl to discuss what’s new with solder mask, including direct imaging and inkjet printing of solder mask, and what PCB manufacturers and OEMs need to know.

Patty Goldman: Welcome, gentlemen. We’re interested in finding out what our readers need to know with regard to solder masks, including the challenges and problems, especially the rapid changes our industry is experiencing. Please introduce yourselves and tell us about Electra Polymers.

Shaun Tibbals: Electra Polymers was founded in 1984 specifically to manufacture coatings for printed circuit boards. In 1984, the main products were screen-defined two-pack epoxy solder mask and UV solder mask, and then we went on to formulate photoimageable materials in the mid to late ‘80s. We’ve continued to make solder masks for the printed circuit board industry, but as the years have gone by, we’ve also diversified into other markets— still within the electronics business, but more focused on the semiconductor end. We now manufacture and supply wafer-level packaging resists to the semiconductor business. There’s quite a crossover in terms of technologies and close to 30% of our business is now in that sector.  I am the sales and marketing director for Electra Polymers. I’ve held several positions within the company ranging from technical and quality positions to sales positions.

Antony Earl: I’m the technical support and quality manager. Like Shaun, I’ve been here for quite a long while and held a variety of positions, from quality control testing to field and internal technical support and formulations. Currently, I look after the technical support activities and the ISO quality and environmental systems for the company.

Goldman: Thanks, so let’s get into some details. What do you see coming up that’s new in the area of solder masks? What are the challenges facing circuit board manufacturers?

Tibbals: I would say the two main challenges are 1) smaller features, and 2) final properties of the boards and therefore solder mask. Circuit boards are getting smaller, and the features are getting tighter. So, what does that mean for a solder mask? Well, it really means two main things. Via holes are getting smaller and more densely packed and overall registration is getting tighter. So, from a solder mask perspective, you need to be able to resolve small features, but you also need to be able to remove the solder mask from very small holes. Those two things really pull in opposite directions, because the more you try to clear small holes, the more potential problems you face with undercut of small features on the board surface due to the prolonged developing stage.

To read the full version of this article which appeared in the July 2018 issue of PCB007 Magazine, click here.