| 摘要 |
PURPOSE:To prevent unnecessary solder from sticking and prevent poor contact at a contact point section from occurring by covering a joint section of a solder layer and the contact point section and the contact point section itself with a protective film and making the solder layer of a homogeneous alloy by heating and melting. CONSTITUTION:A metallic layer 1 including a contact point section 3 is masked with a photoresist film 4 and solder-plated to form a solder layer 5 connected to the contact point section 3. The photoresist film 4 is then removed. Using the solder layer 5 and the contact point section 3 as a mask, the metallic layer 1 just below the mask is etched to form a circuit conductor 6. Then a protective film 8 for covering a joint section 7 between the contact point section 3 and the solder layer 5 and for covering the contact point section 3 is formed. After melting the solder in the solder layer 5 to make it homogeneous, the protective film 8 is peeled off to obtain a circuit board. This makes it possible to prevent unnecessary solder from sticking and to prevent poor contact at the contact point section from occurring.
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