Influence of Manufacturing Mechanical and Thermal Histories on Dimensional Stabilities of FR4 Laminate and FR4/Cu-Plated Holes

Abstract

Irreversible dimension changes of an FR4 laminate board in the z-direction and FR4 laminate/Cu plated holes that depend on their manufacturing histories have been studied by thermal mechanical analysis in the temperature range from room temperature to 240 °C. It is found that the compression residual stresses generated in both materials due to manufacturing pressing are released during heating, leading to an elongation in the specified direction. This increase depends on the composition of the studied composite and number of pressing cycles. The second reason for the observed dimensional changes is insufficient curing during manufacture that causes post-curing after the first heating cycle and related board shrinkage in the z-direction. The temperature regions of these two processes are not the same. The post-curing process occurs in the transition temperature range (near the glass transition temperature), whereas the release of the compression residual stress is observed at higher temperatures. Both these processes are temperature-dependent and do not proceed to completion during one heating cycle. Moreover, the compression residual stress strongly influences the post-curing process.

Investigation of Impacts on Printed Circuit Board Laminated Composites Caused by Surface Finish Application

“…The gradual curing process and stress release of the laminate were detected by the following measurements of the same sample. This observation is in accordance with the findings in the literature conducted by Rudajevová and Dušek [ 41 ]. A new outcome can be found for the impact that causes the application of an HASL surface finish from a thermomechanical point of view.…”

Recovery of Metals from Heat-Treated Printed Circuit Boards via an Enhanced Gravity Concentrator and High-Gradient Magnetic Separator

“…Epoxy resin is the adhesive of PCB, and its glass transition and thermal decomposition occur at a high temperature [ 26 , 27 ].The waste PCBs was subjected to heat treatment for the better metal liberation, but thermal decomposition should be avoided due to the potential release of noxious gases [ 28 , 29 , 30 ]. Keeping the heat temperature between the glass transition and thermal decomposition ones is the ideal condition to achieve an improved liberation.…”

Study on Effects of Nonlinear Behavior Characteristics of Prepreg Dielectric on Warpage of Substrate under Laminating Process

“…However, in thermal processes, the nonlinear behavior characteristics of insulating materials in the substrate have greater effects than the stiffness of the substrate, making it very difficult to predict the warpage [ 14 , 15 ]. In the semiconductor packaging field, studies on the nonlinear behavior characteristics of materials have been actively conducted, which mainly target the underfill film or molding encapsulant [ 16 , 17 , 18 , 19 ]. Recently, however, many studies on nonlinear behavior characteristics of insulating materials in the substrate have been conducted.…”