Substrate technologies are an increasingly critical aspect of the IC package. They continue to advance with each new requirement for cost reduction, space savings, higher speed electrical performance, finer pitch, die surface fragility, new reliability requirements, and new applications. Packaging engineers must fully understand these technologies to design and fabricate future high-performance packages with high yields at exceptional low-costs to give their company a critical competitive advantage. Substrate Technology is an 8-hour course that details the manufacturing; processes; and materials selection, tailoring, and development of substrates. Each fundamental substrate type will be discussed, including traditional FR-4 and CEM-3 materials, Polyimide, Benzocyclobutene (BCB), Bismalemide triazine (BT), Build-up films (e.g., ABF), and newer materials such as silicon and glass substrates. Additionally, future directions for packaging technology will be highlighted, along with challenges that must be surmounted to succeed.