All-Prepreg Laminated over Via-Post

ACCESS fabricates IC substrates by laminating dielectric materials over both metal feature layers and over via post layers. The dielectric material is provided as prepreg consisting of glass fibers in a polymer matrix. the ACCESS coreless process have better planarity, better flexural strength and better warp control, than drill & fill vias, partly in consequence of the permanent, Low coefficient of thermal expansion CTE, High Young's modulus prepreg laid over the generated Via Post and metal features. This material combination allows better support to the chip mounted on the substrate and increases the package reliability for a given form factor and layer count.