Ngk Spark Plug Company, Limited

Chie Honda

Hiroyuki Takahashi

Tatsuya Kato

Shigeru Taga

Tomohide Yamada

An electrical testing substrate unit includes a multi-layer ceramic substrate formed of mullite and a borosilicate glass as predominant ceramic components. In the multi-layer ceramic substrate, the borosilicate glass contains an alkali metal oxide in an amount of 0.5 to 1.5 mass %. The multi-layer ceramic substrate has a mean coefficient of linear thermal expansion having a value of 3.0 to 4.0 ppm/&#xb0; C. between &#x2212;50&#xb0; C. and 150&#xb0; C. A thermal expansion coefficient, &#x3b1;1, of the multi-layer ceramic substrate as determined at a particular temperature and a thermal expansion coefficient, &#x3b1;2, of a to-be-tested silicon wafer as determined at the same temperature silicon satisfy a relation: 0 ppm/&#xb0; C.&#x3c;&#x3b1;1&#x2212;&#x3b1;2&#x2266;2.5 ppm/&#xb0; C. through the temperature range of &#x2212;50&#xb0; C. to 150&#xb0; C. Electrodes are formed on a surface of the multi-layer ceramic substrate.

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Kurashiki, Japan

Chie Honda