Laser Exfoliation Removal of Conformal Coatings

Reliability Society

The IEEE Boston Reliability Chapter cordially invites you to attend a joint meeting and plant tour with SMTA Boston Chapter and iMAPs organizations on November 1, 2017 with Norman Armendariz, Ph.D., Raytheon Engineering Fellow.

Laser Exfoliation Removal of Conformal Coatings From CCA PCB Pad Surfaces and Design for Rinsability

Circuit Cards Assemblies-CCAs are manufactured to meet Class 3 military-grade requirements –they must work the first time, every time. Certain electronic components from recent production builds were detected with cleaning residue remaining, and it appears that the component housing design is a major factor that determines whether a component entrains & entraps residues. To ensure protection to moisture or extreme environments, the CCA undergoes a conformal coating process on CCA exposed surfaces. Prior to conformal coat, the surface of the CCA is semi aqueous chemically cleanedto provide a surface condition suitable for the coating to properly adhere. However, If the cleaning solutions get entrained / entrapped within the components, residual contamination may cause materials degradation of the components, which may limit the electrical performance of the device. As a result, a study was initiated to understand the susceptibility of entrainment / entrapment of cleaning residues on 28 different components, each with various component cover / attachment constructions and vent open areas.

CCAs-circuit card assemblies for military applications require a high level of performance and reliability, and typically undergo a CC-conformal coating process after SMT-surface mount technology assembly to protect the circuit card and attached electrical components from exposure to moisture and harsh environments. However, certain areas of the CCA or PCB-printed circuit board metallized surfaces are desired to be free of conformal coating and are required to be clean, solderable and electrically / thermally conductive. Current conformal coating de-masking processes are time consuming and labor intensive. A more cost effective and automated laser-aided exfoliation method was evaluated and successfully demonstrated to remove parylene C conformal coatings from ENIG-plated Cu pads. The parylene was removed within a precise pad area, and tested to be solderable to enable subsequent wire-soldering and consistent sealant coverage in a cost-effective manner. This paper will discuss the “physics” of laser ablation, laser exfoliation, materials interactions, test and characterization methods used to evaluate and validate the laser-aided removal processes on actual production CCA product.

Norman Armendiraz, Ph.D. of Raytheon Company

Biography: Dr. Armendariz is an Engineering Fellow at Raytheon responsible for materials engineering design, materials analysis, process equipment development, and production support associated with the manufacturing of CCA- circuit card assemblies used in missiles, smart munitions, ground based radars, and mobile sensors across multiple US and international sites. Norm has over 20 years of industrial experience, having worked for Lockheed/NASA, Motorola, TI and Intel, and as Director of Labs / Asst. Engr. Prof. at American University. He holds an interdisciplinary PhD in Chemical Engr. from New Mexico State University, MS in Materials Science Engr. from the University of Illinois at Urbana-Champaign, and BS Metallurgical Engr. from Colorado State University, with 9 US patents and 27 peer-reviewed publications.

Registration/Arrival Details: (US Citizens Only)
* Pre-registration is required, walk-ins will not be able to pass the guard at the gate.
* Raytheon is a secure facility – escort is required at all times while on the premises
* YOU MUST bring proof of US Citizenship to avoid any entry issues. this can be a valid driver’s license, passport, or government issued photo ID.
* You will need to provide first, middle and last name along with company affiliation during registration
* Head count limit is 60, first come first serve, please register early.
* You must register with online RSVP to get on the attendee list! or copy this url to your browser – https://events.vtools.ieee.org/m/47564

Cost:
* SMTA, iMAPS & IEEE Members who RSVP in advance: $20
* Non-Members: $25
* Cost includes: Dinner, tour, networking and presentations
* Payment will be accepted at the door. Cash, checks or credit cards accepted.

Agenda:
5:00 PM Attendee Registration
5:15 PM Raytheon Facility tours
6:00 PM Dinner in Raytheon, Andover Cafeteria
7:00 PM Boston Chapter Welcome — SMTA Chapter President Michael Jansen
7:10 PM Raytheon Welcome
7:25 PM Laser Exfoliation Removal of Conformal Coatings From CCA PCB Pad Surfaces, Norman Armendariz, Ph.D., Engineering Fellow
8:30 PM Q&A and Adjourn

Meeting Location: Raytheon Company, 350 Lowell Street, Andover, Massachusetts