What is Lay-up
Lay-up is the process of stacking layers of materials, such as laminate and pre-preg, in a specific order to create a multilayer PCB. This technique is a step in the manufacturing process of multilayer PCBs.
Various materials, including inner cores, prepregs, and copper foils, during the lay-up process, are carefully arranged and aligned on a stack. The height and position of the stack are determined by tooling pins and caul plates, respectively. This meticulous arrangement aims to ensure that the layers will be bonded together effectively during the subsequent lamination process.
Lamination, also known as multilayer lamination, involves subjecting the stack of materials to high temperature and pressure. This pressing operation results in the layers being firmly bonded together, forming the desired multilayer PCB structure.
A controlled environment is necessary to ensure the lay-up process’s success. This includes maintaining positive air pressure, using filtered air with a particle size of 5 microns, and daily cleaning of the lay-up room to minimize contaminants. Operators must wear clean protective gloves, lint-free lab coats, and caps to prevent any contamination from their clothing or body. Additionally, the temperature and humidity in the lay-up environment should be controlled within specific ranges, typically around 20 degrees Celsius with a relative humidity of 50%. Proper cleaning of lamination fixtures and accessories is also essential.