Multilayer pcb consists of multiple layers of electronic circuits sandwiched together, only a layer of substrate or substrate of the single-layer pcb is different, multilayer pcb has several layers of substrate, each layer has a thermal insulation layer bonded together. It is mainly used in complex electronic circuits that require high-speed circuits, EMI shielding, or a large number of connections. The main advantage is its high assembly density. Components can be deployed on both sides of the board, while additional circuit layers can be integrated internally. Saves space, improves overall performance by reducing the interconnect harness, and can also be dedicated to grounding, with another layer dedicated to the power supply. This creates a large power plane capacitor that helps reduce electromagnetic interference (EMI), thereby improving signal quality. They are found in a variety of applications, including computers, medical devices, automotive systems, GPS technology, and more.