| 摘要 |
PROBLEM TO BE SOLVED: To obtain a pattern width precision that can be used fully even if the pattern width precision is millimeter wave band and at the same time achieve a low-loss circuit. SOLUTION: Holes 8a and 8b for via holes are drilled to alumina substrates 2-1 and 2-2 individually one by one at the stage of a green sheet, a required machining such as filling of such conductive material as tungsten is made to the holes, and then the alumina substrates are baked simultaneously at a baking temperature exceeding 1,300 deg.C. Thin-film strip lines 5 and 6 are formed on the conductor surfaces of the baked alumina substrates 2-1 and 2-2 by the thin- film conductor forming technology. A non-baked low-temperature baking glass substrate 3 that is subjected to the machining of the via hole for connecting the thin-film strip lines 5 and 6 is pinched between the alumina substrates 2-1 and 2-2, thus performing low-temperature baking. |
