Using a new photoimageable dielectric for PWB sequential build-up technology

Abstract

Shipley has been developing products to meet the demands of sequential build-up (SBU) technology for about five years. Shipley has worked closely with customers in evaluating these technologies, and are also involved in a US government initiative for low cost PWBs produced using a sequential manufacturing process. Our initial photodielectric, Multiposit(R) 9500, exhibited excellent plated metal adhesion, good imaging, aqueous developability, and outstanding material properties. As part of the ongoing effort, a new material, Multiposit(R) XP-96700, is under development. This new material exhibits the same material properties, including plated metal adhesion and good electrical properties, as Multiposit(R) 9500, but also exhibits improved processing, via shape, and photospeed. This new material is the centrepiece of a total process solution under development which uses the concept of a "factory within a factory" to allow the coating and imaging of this material in a clean environment within the normal PWB manufacturing shop floor. This paper presents preliminary information on a new photodielectric material, including data on via resolution and plating, plated metal adhesion, and physical and electrical properties of the cured material. We discuss and analyse some of the challenges facing SBU technology with regard to cost, reliability, planarization, PTH processing, and yield. Our goal is to explore the use and characterization of this new dielectric material using an integrated approach of imaging and metallization through to final board finish and testing.