FR4 copper clad laminates

FR-4is the primary insulating backbone upon which the vast majority of rigid printed circuit boards (PCBs) are produced. A thin layer of copper foil is laminated to one or both sides of an FR-4 glass epoxy panel. These are commonly referred to as copper clad laminates. FR-4 copper-clad sheets are fabricated with circuitry interconnections etched into copper layers to produce printed circuit boards. More sophisticated and complex FR-4 printed circuit boards are produced in multiple layers, also known as multilayer circuitry. When ordering a copper clad laminate board, the FR-4 thickness and the copper foil thickness must be specified separately. FR-4 thickness is specified in thou or inches, and common thicknesses range from 10 thou (0.010 in, 254 µm) to 3 inches (76 mm). copper foil thickness is specified in units of ounces per square foot (oz/ft2), commonly referred to simply as ounce. Common thicknesses are 1 oz/ft2 (300 g/m2), 2 oz/ft2 (600 g/m2), and 3 oz/ft2 (900 g/m2). These work out to thicknesses of 34.1 µm (1.34 thou), 68.2 µm (2.68 thou), and 102.3 µm (4.02 thou), respectively. Some PCB manufacturers refer to 1 oz/ft2 copper foil as having a thickness of 35 µm (may also be referred to as 35 μ, 35 micron, or 35 mic). 1/0 - denotes 1 oz/ft2 copper one side, with no copper on the other side. 1/1 - denotes 1 oz/ft2 copper on both sides. H/0 or H/H - denotes 0.5 oz/ft2 copper on one or both sides, respectively. 2/0 or 2/2 - denotes 2 oz/ft2 copper on one or both sides, respectively. Key Features and Benefits: —High dielectric strength — Radiation resistant — High tensile strength — Low cold flow or creep — Chemically resistant — Dimensional stability — Low dissipation factor — High impact strength