Introduction

Electronic packaging is the art and science of creating a physical electronic product—the art being the development of new and unique electronic products whose concepts are born through human activities, and the science representing the sum of human knowledge in the various engineering disciplines employed in the creative process. Electronic packages provide the medium for electrical bridges or interconnections, as well as the mechanical support and protection of the delicate electronic circuitry. The extension of the metal lead frame in the chip carrier to the outside of the package serves to connect the chip circuitry to the second level of packaging. One of the chief mechanical concerns is the development of stresses in electronic packages. Satisfactory design of electronic systems depends on the acceptable performance of electrical functions at all levels of the packaging hierarchy. Increased demand for sophisticated electronics and the competitive pressure to meet market windows have placed a heavy burden on design engineers.