In PCB boards, copper substrates are the most expensive type of metal substrates, with thermal conductivity many times better than aluminum and iron-based substrates. Generally, there are gold plated copper substrates, silver plated copper substrates, tin sprayed copper substrates, and oxidation resistant copper substrates. Suitable for the heat dissipation and building decoration industries of high-frequency circuits, regions with large changes in high and low temperatures, and precision communication equipment.