How is a PCB made ?
What determines impedance ?
www.polarinstruments.com
Version IIa
Manufacturing ProcessesManufacturing Processes for a Multi-layer PCBThe following presentationcovers the main processesduring the production ofa multi-layer PCB.The diagrams which followrepresent a section througha 6 layer PCB, as indicatedin red.2Tracks under solder maskVia holeSMD PadSection through PCBwww.polarinstruments.comTypical Layer Construction - 6 Layer PCBCopperLaminateLayer 1 (Outer)FOILPRE-PREGLayer 2 (Inner)Layer 3 (Inner)INNER LAYERPRE-PREGLayer 4 (Inner)Layer 5 (Inner)INNER LAYERPRE-PREGLayer 6 (Outer)FOIL3Manufacturing ProcessesImpedance Considerations?Layer build / stackup is one of the most important aspects of controlled impedance?Many combinations of material thickness and copper weights can be used. ?PCB Fabricators manufacturing techniques varywww.polarinstruments.comManufacturing Processes– Material SelectionInner Layer Processing Inner Layer Processing –CopperLaminate (Dielectric)Layer 2 (Inner)Layer 3 (Inner)4CoreImpedance Considerations?Selecting inner layer Core materials is very important when using embedded microstrip and offset stripline structures?Inner layer Core materialsare usually processed as “Layer pairs”www.polarinstruments.comLaminating and Imaging of Internal LayersUV sensitive film is laminated over top and bottomsurfaces of the CoreAreas of the Core where no copper is required are left exposedLayer 2 (Inner)CoreLayer 3 (Inner)5Manufacturing ProcessesImpedance Considerations?Does not effect impedancewww.polarinstruments.com
电路板阻抗介绍(Polar公司提供)
