Thermal and mechanical characterization of ViaLux(TM) 81: a novelepoxy photo-dielectric dry film (PDDF) for microvia applications

摘要

Multilayered high density interconnect (HDI) processing on organicsubstrates typically introduces warpage and residual stresses. Themagnitude of the warpage and the residual stresses depends on, amongother factors, the processing temperatures and the thermomechanicalproperties of the dielectric and substrate materials. In this work, aprospective epoxy-based dielectric material for such sequentially builtup (SBU) high density-interconnect printed wiring boards (HDI-PWB) isconsidered. The polymer is a photo-dielectric dry film (PDDF) materialcalled ViaLux^TM 81, which exhibits a complicated curingbehavior due to the long lifetime of the cationic photoinitiatorsgenerated by ultraviolet (UV) exposure. The objectives of this work are:(i) to conduct differential scanning calorimetry (DSC) experiments anddevelop a cure kinetics model; (ii) to develop a cure shrinkage modelbased on thermal and chemical shrinkage experiments; and (iii) todetermine the thermomechanical properties of partially and fully curedVialux^TM 81 dry film. All of these experimentalcharacterizations are necessary to select suitable process parametersand to obtain a consistent product with the desired physical andmechanical properties