11. Fundamentals of Advanced Materials and Processes in Organic Substrate Technology

In the past several decades, Moore’s law has successfully predicted integrated circuit (IC) technology advancement. However, IC technology began hitting both technology and cost barriers. Conventional die shrinkage and advanced deep-submicron semiconductor technology is no longer able to meet the cost-to-performance ratio that the world desires in the near future. Three-dimensional (3D) packaging has caught broad attention and is poised to help continue the Moore’s law by vertically integrating multiple IC chips into same footprint. In order to enable highly integrated 3D packaging, both the substrate and the printed wiring board (PWB) receiving the 3D package need to meet the signal and power density requirements. Substrate material and fabrication technologies play critical role in succeeding the future needs of smaller size, lower cost, and higher performance.

In this chapter, an overview of the substrate technology evolution in the past several decades will be discussed. The overview covers the substrates used in large varieties of packages, such as dual-in-line packages (DIP), quad flat package (QFP), area array package, and embedded wafer level ball grid array (eWLB) packages. The materials used in substrates will be discussed with a concentration on organic substrate materials. The discussion will cover key consideration points in material selection and application. The substrate fabrication technology will be also discussed in detail. The process technologies on the fabrication of cores, build-up dielectric layers, metal layers and traces, plated through holes (PTH) and vias, contact pads, solder mask, in addition to surface finishes will be covered. The general recommendation in selecting and applying the appropriate process technologies will be recommended.