Sumitomo Metal (Smi) Electronics Devices, Inc.

Chiaki Higuchi

Masashi Fukaya

Yoshinobu Watanabe

Koji Shibata

Tomoko Matsuo

A thick-film resistor contains RuO and an SiO &mdash;B O &mdash;K O glass having a composition of 60 wt %&lE;SiO &lE;85 wt %, 15 wt %&lE;B O &lE;40 wt %, 0.1 wt %&lE;K O&lE;10 wt %, and impurity &lE;3 wt %. A ceramic circuit board includes a thick-film resistor printed on it, the thick-film resistor containing RuO and an SiO &mdash;B O &mdash;K O glass having the above composition.

Thick-film resistor and ceramic circuit board

A thick-film resistor paste consists of a first glass powder, a second glass powder, a conductive material powder, and an organic vehicle. A quantity of the first glass powder mixed is larger than a quantity of the second glass powder mixed. The first glass powder contains, in total, 95 percentage by weight or above of CaO of 20 to 26 percentage by weight, SiO.sub.2 of 37 to 59 percentage by weight, Al.sub.2 O.sub.3 of 5 to 13 percentage by weight and B.sub.2 O.sub.3 of 8 to 28 percentage by weight. The second glass powder contains, in total, 85 percentage by weight or above of SiO.sub.2 of 53 to 72 percentage by weight, B.sub.2 O.sub.3 of 20 to 30 percentage by weight and Na.sub.2 O of 1 to 7 percentage by weight. The thermal expansion coefficient of the first glass powder is larger by 0.5.times.10.sup.-6 /deg or above than the thermal expansion coefficient of the second glass powder. A glass transition point of the first glass powder is higher by 30 degrees Celsius or above than a glass transition point of the second glass powder.

Growing community of inventors

Ebina, Japan

Chiaki Higuchi