TY  - JOUR
AB  - Purpose The purpose of this study/paper is regarding analysis of electrical discontinuity in penultimate layer of a few batches ofMultilayer Boards (MLB) fabricated and supplied by a vendor. The ever-increasing demand of miniaturization in launch vehicle and spacecraft electronics systems has led to the usage of multilayer printed circuit boards (PCBs) for realizing high-performance electronics circuitry. Multilayer boards (MLBs) fabricated by qualified agencies based on the customer requirement are being used in the critical launch vehicle/spacecraft systems after evaluating the preliminary test results supplied by the vendor. However, a few batches of MLBs fabricated and supplied by a particular vendor (“A”) showed a discontinuity problem in a few PCB tracks connected by soldering pads. As these MLBs are part of Flight critical systems of both launch vehicle and spacecraft, a malfunction in the board may lead to fatal errors during fight or on-orbit, thereby jeopardizing the mission.Design/methodology/approach A systematic approach was followed to have a thorough understanding of the problem, and major tests such as inspection, continuity measurement, microsection of the plated through hole (PTH) and Scanning Electron Microscopy–Energy Dispersive X-ray Analysis tests were conducted on identified test boards based on Ishikawa model. Emphasis was given for horizontal microsection, as it has got a clear edge in detecting defects at any point of PTH barrel to inner-layer copper interface.Findings Systematic testing and evaluation on specimen revealed the presence of unwanted material at the bonding area of inner-layer copper and PTH copper due to inadequate fabrication process. The un-cleaned epoxy materials present at the bonding area creates a weak bond between barrel and inner-layer copper. Electrical strength of the MLB is the strength of this link. This weaker interconnection leads to electrical discontinuity of inner-layer tracks.Originality/value MLBs are part of Flight critical systems of both Launch Vehicle and Spacecraft; a malfunction in the board may lead to fatal errors during fight or on-orbit, thereby jeopardizing the mission. Case study of an original failure observed in MLBs helped to achieve normal functioning of systems and avoided failures at later stage of mission.
VL  - 42
IS  - 4
SN  - 0305-6120
DO  - 10.1108/CW-08-2016-0036
UR  - https://doi.org/10.1108/CW-08-2016-0036
AU  - Jayaprasad G.
AU  - Dhanlakshmi P.P.
AU  - Hemachandran S.
PY  - 2016
Y1  - 2016/01/01
TI  - Analysis of electrical discontinuity problem in MLB using Ishikawa model
T2  - Circuit World
PB  - Emerald Group Publishing Limited
SP  - 201
EP  - 206
Y2  - 2024/05/04
ER  -