| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a thick film circuit board provided with a copper conductor thick film circuit having high shape accuracy, a low resistance, and a sufficiently high adhesive strength to the circuit board. SOLUTION: After conductive paste containing a conductive component composed of copper powder, glass frit, and a cellulose resin as main ingredients and an organic vehicle is applied to the circuit board, the board is baked. At the time of baking the board, (a) the oxygen concentration is adjusted to 200-500 ppm in the temperature region until the temperature reaches 350 deg.C at temperature rising time, and (b) the baking atmosphere is adjusted to substantially contain no oxygen (for example, a nitrogen atmosphere) in the temperature region of >350 deg.C. Consequently, the cellulose resin can be removed surely and the circuit board can be baked sufficiently while the oxidation of the copper powder is prevented.
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