The surface printed circuit board is a product developed mainly in the United States with the emergence of transistors in the early 1950s. At that time, the main production method was the direct etching method of copper foil. From 1953 to 1955, Japan used imported copper foil to make paper phenolic copper foil substrate for the first time, and it was widely used in radios. In 1956, after the emergence of a Japanese professional circuit board manufacturer, the manufacturing technology of single-sided panels developed rapidly. In terms of materials, paper-based phenolic copper foil substrates were mainly used in the early days. However, due to factors such as low electrical insulation, poor soldering heat resistance, and distortion of phenolic materials, paper-based atmospheric resins, glass fiber epoxy resins, etc. Developed, the single-sided boards required by current consumer electronic machines almost use paper phenolic substrate boards….