| 摘要 |
PURPOSE: To obtain a conductor and metal coating of a hole of a microcircuit board surface by selecting a thickness of a conductive material layer on a circuit board surface independently of a thickness of the material layer in the hole. CONSTITUTION: After a hole 4 is formed on a board 1, before coating of the hole 4 with a conductive material 9, a surface of the board 1 is coated with solder-stopping mask 7, exposed and developed. In this process, a thickness of the material 3 layer on the surface of the board 1 can be selected independently of that of the material 3 layer on the surface of the board 1. In this case, the thickness of the material 3 layer on the surface of the board 1 is about 10 to 45 micron or preferably about 15 to 18 micron. The thickness of the material 9 layer in the hole 4 is about 5 to 30 micron or preferably about 23 to 28 micron. Thus, a conductor (metal foil) 3 of the surface of the board 1 and the conductive material (coating metal) 9 of the hole 4 can be obtained. |
