Method of manufacturing brake pedal coil printed circuit board for vehicle

A method of manufacturing a brake pedal coil printed circuit board for vehicles, comprising:

• preparing a first epoxy layer having first copper foil laminated on both surfaces thereof;
• laminating each of second epoxy layer m the first copper foil, and laminating second copper foil on each of the second epoxy layers;
• forming a through hole passing through upper and lower surfaces of lamination of the first epoxy layer, the first copper foils, the second epoxy layers and the second copper foils, performing electroless copper plating on an inside surface of the through hole and the second copper foil, and forming an electrolytic copper-plated layer on each of the electroless copper-plated layer of the through hole and the electroless copper-plated layer formed on the second copper foil;
• forming circuits having a predetermined pattern on both of the electrolytic copper-plated layer and the electroless copper-plated layer and forming a gap between the circuits to have the same size as the circuits;
• applying a photo solder resist (PSR) ink onto both of the electrolytic copper-plated layer excluding the through hole and a hole land, wherein the hole land is a portion of a conductive material partially exposed near both of upper and lower peripheral ends of the through hole, the conductive material being a material electrically connecting the both of the upper and lower peripheral ends of the through hole;
• applying a marking ink onto the PSR ink;
• forming a nickel (Ni)-plated layer around the through hole and the hole land;
• and
• forming a gold (Au)-plated layer on the Ni-plated layer, wherein, in S300, the electroless copper-plated layer is formed to have a thickness of 1.3 μm to 1.7 μm by performing the electroless copper plating at a temperature of 40° C. (±2° C.) for 28 minutes in a plating solution which includes 82 g/L of copper sulfate, 155 g/L of ethylenediamine tetraacetic acid (EDTA), 32 mL/L of formaldehyde (HCHO), 42 g/L of sodium hydroxide (NaOH), 0.12 g/L of polyethylene glycol (PEG), and 83 mg/L of bipyridyl.