| abstract |
In the glass-ceramic composition, a weight ratio of a glass and a ceramic is 40 to 60:60 to 40. The glass is composed of 40 to 60 wt % of SiO2, 5 to 9 wt % of Al2O3, 1 to 10 wt % of B2O3, 3 to 5 wt % of Na2O+K2O, 3 to 15 wt % of CaO+MgO+ZnO, and 15 to 40 wt % of PbO, and does not contain Li2O. A softening point of the glass is 650 to 780° C. The circuit substrate includes a laminate substrate formed by laminating insulating substrates, and a conductor circuit formed on a surface of each insulating substrate. The insulating substrate is formed of the glass-ceramic composition. A wiring layer and a via hole conductor are provided inside the laminate substrate. |