| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure for embedding conductive paste in blind hole of circuit board that can improve the embedded reliability of conductive paste at low cost. SOLUTION: A circuit board 1, constituted by respectively forming conductor layers 3a and 3b on both surfaces of a resin substrate 2, is prepared, and a prescribed circuit pattern and an opening 4 are formed in the conductor layer 3a, formed on the blind hole 10 forming-side surface of the substrate 2 through etching. At the same time, a plurality of very small openings 5, having prescribed opened diameters, is made through the conductor layer 3b at the position corresponding to the opening 4 of the conductor layer 3a. In addition, a blind hole 10, having the same diameter as the opening 4 has, is made through the substrate 2. A screen 20 is placed on the board 1 from the conductor layer 3a side and conductive paste 11 is applied from the upside of the screen 20. Then printing is performed by scratching the applied paste 11, in the direction shown by the arrow in the figure by means of a squeegee 12. Since air escapes through the very small openings 5, formed through the conductor layer 3b as the paste 11 enters the blind hole 10, no bubble is generated, and accordingly, hollow section will not be formed in the hole 10. |
