Essentials of Electronic Packaging: A Multidisciplinary Approach
2 Substrate and Laminate Technologies
Substrates and laminates constitute the fundamental building blocks of any electronic appliance or product. The silicon devices with electronic functionalities have to be configured and packaged so that they can be assembled on to a carrier. These packages in turn have to be assembled onto the next level carrier so that it forms a subsystem sometimes referred to as second-level assembly, package, or circuit card assembly. Thus, the vital function of the substrates and laminates is enabling connectivity of the different elements. Hence, substrates and laminates constitute platforms onto which either single or multiple devices are packaged, or a number of packaged devices themselves are mounted. The nature of the platforms depends on the characteristics and complexity of the devices or packages being assembled. Electrical, thermal, and mechanical limitations imposed by the devices and packages have to be carefully considered in the design and fabrication of these carriers.
There are a number of carrier and laminate technologies that have been developed over the years to suit product designs and applications. Historically, the printed wiring board (PWB) technology development lagged behind the rapid growth of semiconductor technologies. Higher and higher I/O devices with higher functionalities, reduced footprints, and ever-finer feature sizes are being introduced. Concurrent developments in laminate technologies have become a necessity to meet the emerging technology trends and demands. A broad range of materials and processes are employed.
This chapter presents an overview of the basic substrate, laminate, and carrier technologies used for first- and second-level packaging. Also, the emerging trends in carrier technologies are discussed here.