| 摘要 |
PURPOSE:To obtain a printed wiring board having a connection structure, wherein a circuit of upper layer and a circuit of lower layer can be connected to each other sufficiently and strongly and no disconnection is generated, by a method wherein an insulating layer is formed at a sufficient interval from a conductive layer of lower layer. CONSTITUTION:A sufficient interval (d) exists between an end part 7a of an undercoat 7, which is provided under a conductive circuit 4 of a copper paste, and a connection land 2 of a conductive circuit of lower layer. That is, the end part 7a of the undercoat 7 results in existing at a position, where is not affected by a step 8 of a solder resist layer 6, by this interval (d). Accordingly, as the interval 9 between the step 8 of the layer 6 and the end part 7a of the undercoat 7 is increased, the copper paste is evenly applied within this interval 9 and the generation of disconnection is eliminated. Moreover, the undercoat 7 is printed sufficiently apart from the land 2, the bleeding of the land 2 to a contact area 5 is not generated and the connection between the upper and lower circuits 4 and 2 becomes possible with a good connection resistance and a good strength. |
