SMT007 Magazine


Issue link:

Contents of this Issue


Page 75 of 105

76 SMT Magazine • November 2017 by Stephen Las Marias I-CONNECT007 American Computer Development Inc. (ACDi) started approximately 30 years ago as a PCB design and layout service bureau. Today, the company does about 350 to 400 unique PCB layouts per year for a variety of customers across different industries, including medical and in- dustrial fields. Around 15 years ago, ACDi acquired a lo- cal manufacturing plant, enabling it to ramp up into design, layout, and prototype assembly. Five years ago, the company purchased another facility in North Carolina for production-type runs. Garret Maxson is the manager of engineer- ing services at ACDi. He currently oversees 11 direct reports, and most of them are PCB layout designers, AutoCAD drafters, and component librarians. In this interview Maxson discuss- es the PCB assembly challenges when dealing with high-density interconnect (HDI) boards, parameters to consider, and strategies to help facilitate a smooth assembly process when using HDI boards. Stephen Las Marias: What are the challenges in PCB assembly when it comes to dealing with HDI boards? Garret Maxson: As the boards get denser and denser, obviously we get into high-density in- terconnect boards. There are a variety of via structures due to the pitches of the parts, and how small the IC manufacturers are making them. What that often leads to is new via tech- nologies, whether they're buried vias or blind vias, or microvias—a lot of companies will start putting them in the pad, which can lead to is- sues if the assembly is not done properly. When you put a via in a pad that is going to get sol- dered, you typically want to fill that via, with either a non-conductive or conductive epoxy, and use some sort of plating over the barrel of the via so that you get a smooth pad that you are assembling the part to without a whole lot of surface deviation. The flatter the pad, the eas- ier it is to print solder on the board, and to as- semble the part. As it pertains to assembly, the via-in-pad is one of the larger concerns of the HDI. Other than that, you are mostly concerned with the FEATURE INTERVIEW

Articles in this issue

Archives of this issue

view archives of SMT007 Magazine - SMT-Nov2017