| 摘要 |
<p>PURPOSE:To form as many circuit elements as possible in an inner layer and enable higher-density packaging by making openings in the inner and outer layer substrates, setting the firing temperature of conductor paste used in an after-process low enough not to decrease the electric characteristics, and filling up the openings with an organic insulating material. CONSTITUTION:Openings 6 to form circuit element 7 therein are made in a plurality of green sheets forming the inner and outer layer substrate 1 and 2 of a multilayer circuit substrate, high-temperature type conductor paste to form a film component 7a and inner layer wiring patterns 3 is applied to the openings 6, and the green sheets are laminated, applied by heating, and fired. Outer layer wiring patterns 4 are formed on the outer layer substrates 2 by firing with low-temperature firing type conductor paste of a firing temperature low enough not to decrease the characteristic of a film component 7a formed in the first process. Connection in the openings 6 is performed with the circuit elements 7 or conductor 8 and the openings 6 are filled up with an organic insulating material 9. Short circuit wiring 10 to connect the outer layer wiring patterns 4 to each other is formed on the surface of the organic insulating material 9 with organic polymer type conductor paste of a still lower temperature.</p> |
