Effect of Continuous and Discontinuous Fabrication and Reflow Processes on PWB Warpage

PWB also known as Printed Circuit Board (PCB) provides the physical structure for mounting and holding the electronic components and electrically connecting it. They are foundation of virtually all of the electronic devices. Typically they are multilayer structures consisting of organic/composites (e.g. FR4) and circuit layers, laminated together. Such multi-layered structures exhibit ‘board warpage’ during manufacturing process. It is a result of residual thermo-mechanical stresses along with any asymmetries (if present) during the curing process. This effect further increases when the board undergoes thermal cycling during component mounting and reflow process. Effect of different parameters such as board size, board thickness, and pressure (at the time of developing) on PWB warpage is studied.