Choice of Materials and Usage of Panels
This chapter relates the best practices for choosing materials to manufacture multilayer PCBs that achieve two critical requirements: (1) limit manufacturing problems (e.g., bowing or twisting, as well as mis-registering; and (2) coming up to the standards of performance.
The most important material for PCB manufacturing is raw laminate. It also represents the largest cost of all other materials needed to produce a multilayer PCB. Raw laminate has a critical impact for the prices and the delivery time of PCBs. Therefore, it is important to consider how its construction can be optimized by using regular raw materials, as well as maximizing the usable region of the PCB relative to regular panel dimensions.
The next element to consider is the dielectric thickness, which must be specified for impedance requirements. The dielectric thickness should be chosen from PCB manufacturers that have base laminates or prepreg thicknesses available. Multilayer materials range from 0.125mm to 1mm in thickness. Thin laminates (i.e. 0.1mm or less) are necessary for some low-power applications as well as the continued densification of multilayer circuit PCBs. Thin laminates (which sometimes are referred to as ultrathin) can be purchased with a single ply of glass fabric only.
The specification of different materials should not disappoint PCB engineers from asking for price quotes. Many times, different and low-cost alternatives are available due to the continuing engineering projects.
Engineers should incorporate Environmentally-Conscious Manufacturing (ECM) into their designs because clients will then use designs and procedures that do not create a lot of excess waste materials. For example, if an engineer uses the lightest copper weight (0.5 oz) available, he will see the lowest amount of chemical use, as well as the creation of wasteful by-products. The selection of solder impacts the amount, toxicity and emission of solvents. The selection of anti-tarnish in lieu of hot air solder leveling (HASL) will decrease the amount of lead used and its emission from the fusing oil and the flux.
Welcome to Shenzhen Grande Electronic Co., Ltd.!
