The major trend in the electronic industry today is to make products such as smartphones, tablets, wearables, internet of things, etc. more personal by making them smarter, lighter, smaller, thinner, shorter, and faster, while at the same time making them more friendly, functional, powerful, reliable, robust, innovative, creative, and less expensive. As the trend towards miniature and compact products continues, the introduction of cool products that are more user-friendly and contain a wider variety of functions will provide growth in the market. Some of the key technologies that are helping to make these cool product design goals possible are flip chip, WLCSP (wafer-level chip scale package), and FOWLP (fan-out wafer-level packaging). Their PCB (printed circuit board) assembly and solder joint reliability will be presented and discussed in this lecture. Since wafer bumping is the mother of flip chip and WLCSP technologies, it will be briefly mentioned first.