Description of base material performance parameters for PCB
CCL: COPPER CLAD LAMINATE，raw material for PCB
a) Tg: Glass Transition Temperature, it is the temperature of the transition which between the glass state and the high elastic state (usually said softening). In the PCB industry, this glass-state substance is generally referred to as a dielectric layer consisting of resins or resins and fiberglass fabrics. Our common TG requirements are greater than 135 ℃.Middle TG requirement is greater than 150 ℃.High TG requirement is greater than 170 ℃ The higher the TG value, Usually its heat resistance and dimensional stability is betterb) CTI: Comparative Tracking lndex. The surface of the material can withstand 50 drops of electrolyte 0.1% Ammonium chloride aqueous solution the highest voltage Without any traces of leakage.
c) CTE: Coefficient of thermal expansion, the performance of the PCB board is usually measured by linear expansion coefficient. Defined as the ratio of the increase in length to the original length When the unit temperature changes. Such as Z-CTE. The lower the CTE value, the better the dimensional stability, conversely the worse
d) TD: thermal decomposition temperature, it refers to the temperature of the substrate resin when it is weightless 5%, is the signal of delamination and performance degradation caused by PCB base material heating.
e) CAF: Resistance to ion transfer performance, refers to after applying the voltage on the printed circuit board which is close and parallel to each other. Under the action of electric field, the state of a dendritic metal separating between conductors. Or the transfer of metal ions along the glass fiber surface of the base material（CAF）.Thus reducing the insulation between the wires,
f) T288: is a technical index reflecting the soldering condition of PCB substrate, refers to the maximum time when the substrate of a printed board is subjected to soldering heat without foaming, delamination, etc. under 288 ℃ conditions. The longer the time, the more favorable the soldering.
g) DK: dielectric constant
h) DF: dissipation factor, is the ratio of the energy in the wire that has been lost in the insulating material to the energy in the existing line.
i) OZ: Oz is the abbreviation for symbolic ounce. 1OZ means the thickness of the copper evenly tiled in the area of 1 square feet (FT2) with a weight of 1OZ. It uses the weight per unit area to indicate the average thickness of the copper foil. 1OZ=28.35g/FT2.
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