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30 The PCB Design Magazine • August 2014 to a cascading effect downwards into other mar- ket sectors, and it also shows leadership in qual- ity ideals. While OEMs are often presented as the main barriers to material change, the bottleneck is more likely to be the PCB fabricator. The com- plex nature of manufacturing materials and processes—chemistry, etching, plating, mate- rial preparation, etc.—requires standards and specifications to control the output. This has many levels, from single process steps to corpo- rate specifications and regulatory requirements. Compliance with a standard indicates that you, as an organisation, have taken the time to un- derstand the supply chain. Remember that laminates follow the same basic process manufacturing steps as a PCB. Glass, resin and copper are processed to create laminates, and process steps similar to that of PCBs can introduce faults and lead to material failures. The selection of materials is usually left to the manufacturer, who usually receives a print with very open options regarding material type and composition. Typically, the Tg is given as the basic infor- mation on material type. As circuit speeds rise, a more critical selection of material takes place, with Dk and Df also selected as material guid- ance criteria. Thermal reliability, along with electrical performance, becomes more of a driv- er for specific materials or a particular group of materials, but this is, in the main, left to the PCB fabricator. The fabricator supplies that in- formation to the OEM design department, who then place it on the drawing. Selecting high- speed materials, for example, is something that the OEM design departments are being drawn into, and it is perhaps here that the selection processes become important to the OEM. Hav- ing made the basic selections to fulfil design functionality, choosing a material supplier is often more difficult. Manufacturability is key. How easy is the material to process? This is where the fab shop steps in and tells the OEM which "approved" materials are available for the design. This is based on many things: cost, a strong supply chain, or even spe- cific accreditations. If your material selection process includes suppliers that have regulatory approval or accreditation, then you can usual- ly be assured of quality and reliability. Having your laminate supplier and fabricator accred- ited is vital to demonstrating that your supply chain pipeline is controlled. The OEM typically owns the quality culture for the product. Why not request the same from all of its suppliers? You cannot test faults out of a laminate, be- cause a fault causes a failure. It is this failure feature PCB LAMINATES AND AS9100C continues Figure 1: Chart showing how As9100C covers the entire supply chain.