Glass substrate, laminated substrate, laminate, and method for producing semiconductor package

A glass substrate comprising, as a glass matrix composition as represented by mole percentage based on oxides,

• from 55% to 75% of SiO2,
• from 2% to 15% of Al2O3,
• from 0% to 10% of MgO,
• from 0% to 10% of CaO,
• from 0.5% to 10% of SrO,
• from 0% to 15% of BaO,
• from 0% to 5% of ZrO2,
• from 0% to 20% of Na2O,
• from 5% to 30% of K2O, and
• from 0% to 5% of Li2O,
• wherein:
• a total content of alkali metal oxides (R2O), as represented by mole percentage based on oxides, is from 10% to 23%;
• a total content of MgO, CaO, SrO, and BaO is from 4% to 20%;
• a value obtained by dividing a total content of alkali metal oxides by the content of SiO2 of 0.50 or smaller;
• a value obtained by dividing the content of Na2O by a value obtained by subtracting the content of Al2O3 from a total content of Na2O and K2O of 0.90 or smaller;
• and
• an average coefficient of thermal expansion α1 at 50° C. to 350° C. of from 11 ppm/° C. to 16 ppm/° C., and
• wherein the glass substrate contains substantially no ZnO.