Circuit substrate and manufacturing method thereof

The invention relates to a circuit substrate and a manufacturing method thereof. The manufacturing method is to manufacture the circuit substrate with high heat conducting insulativity. The manufacturing method comprises: firstly, a substrate layer with a configurating surface and a radiating surface is prepared, and the configurating surface and the radiating surface are subjected to anodic treatment respectively so as to form a first anodic treatment layer and a second anodic treatment layer respectively; and secondly, a heat conducting insulation layer is formed on the second anodic treatment layer, and a diamond-like layer is formed on the heat conducting insulation layer. The thermal expansion coefficient of the substrate layer is larger than the thermal expansion coefficient of the second anodic treatment layer; the thermal expansion coefficient of the second anodic treatment layer is larger than the thermal expansion coefficient of the heat conducting insulation layer; and the thermal expansion coeffic