Mike Creeden has been in the PCB design industry for more than 40 years now. In June 2003, he founded San Diego PCB Inc., a design bureau serving a variety of industries, including industrial, automotive electronics, medical diagnostics, internet of things (IoT), defense, aerospace, and communications markets.
The company was acquired by EMS firm Milwaukee Electronics in December of last year. Currently, Creeden is the vice president of layout services for San Diego PCB, which has about 18 designers and supports four CAD platforms. He is also a master instructor at EPTAC, where he works on CID+ certification across the country.
San Diego PCB had the opportunity to be involved on designs requiring HDI. So, for this month’s issue of our magazines, we interviewed Creeden to get his insights on the challenges when it comes to HDI, and how designers and manufacturers can address those issues.
“HDI, along with almost any perspective from PCB design and layout, in my opinion, should consider three perspectives for success: there is a layout solvability, whereby oftentimes there’s a complex packaging challenge involving dense BGAs or fine-pitched BGAs; the electrical integrity—including all those signal integrity and polar integrity considerations; and manufacturability,” explains Creeden. “A designer must approach HDI and any portion of PCB design layout with all three of those perspectives in mind. The solvability is a skillset that a designer would have to essentially understand what it takes to truly satisfy the connectivity of the board. HDI exists in many different forms. For example, via in pad. It would require half the geometry to pin-escape a board if you can put the via right in the pad. Therefore, you must consider the manufacturability of that because now, you have potentially a via filling and a planarization and a plating aspect.
“From an electrical integrity standpoint, when doing via in pad, you essentially are reducing some of the parasitics, by having an extra piece of metal there to perhaps impede or affect the circuitry. Via in pad is a form of HDI. We’re seeing them routinely now in the 1,500 to 2,000 range; there are some BGAs that are way beyond that, but the norm is still somewhere between that neighborhood. With the dense pin-count of the BGA, it becomes difficult to route that out. It really becomes a geometric solve whereby you are going to utilize—even if the pin pitch is normal—an HDI to basically pin-escape in the dense board without adding extra layers.”
To read this entire interview, which appeared in the November 2017 issue of The PCB Design Magazine, click here.