Glass substrate, laminated substrate, and laminate
A glass substrate contains, as a glass matrix composition as represented by mole percentage based on oxides, SiO 2 : 58-75%, Al 2 O 3 : 4.5-16%, B 2 O 3 : 0-6%, MgO: 0-6%, CaO: 0-6%, SrO: 5-20%, BaO: 5-20%, and MgO+CaO+SrO+BaO: 15-40%. The glass substrate has an alkali metal oxide content of 0-0.1% as represented by mole percentage based on oxides. The glass substrate has an average coefficient of thermal expansion α of 56-90 (×10 −7 /° C.) at 50° C.-350° C.
1. A glass substrate comprising, as a glass matrix composition as represented by mole percentage based on oxides,
from 58% to 75% of SiO 2 ,
from 4.5% to 7% of Al 2 O 3 ,
from 0% to 6% of MgO,
from 0% to 6% of CaO,
from 5% to 20% of SrO,
from 9% to 20% of BaO, and
from 15% to 40% of MgO+CaO+SrO+BaO,
having an alkali metal oxide content of from 0% to 0.1% as represented by mole percentage based on oxides, and
having an average coefficient of thermal expansion α of from 56×10 −7 /° C. to 90×10 −7 /° C. at a temperature of form 50° C. to 350° C.,
wherein the glass matrix composition does not contain B 2 O 3 and CeO 2 , and
wherein a thickness of the glass substrate is less than 2 mm.
2. The glass substrate according to claim 1 , wherein a value determined by the following expression (1) that represents a relationship between rates of each of the oxides as represented by mole percentage based on oxides, is from 56 to 90:
0.174×(content of SiO 2 )−0.012×(content of Al 2 O 3 )+0.317×(content of B 2 O 3 )+0.988×(content of MgO)+1.715×(content of CaO)+2.011×(content of SrO)+2.251×(content of BaO)+0.076 (1).
3. The glass substrate according to claim 1 , comprising a total content of SiO 2 and Al 2 O 3 of 65% or more as represented by mole percentage based on oxides.
4. The glass substrate according to claim 1 , which has a weight loss per unit area of 0.3 mg/cm 2 or less, through 20-hour immersion in an HCl solution having a temperature of 90° C. and a concentration of 0.1 N.
5. The glass substrate according to claim 1 , which has a weight loss per unit area of 13 mg/cm 2 or less, through 20-minute immersion in an HF solution having a temperature of 25° C. and a concentration of 5%.
6. The glass substrate according to claim 1 , which has a haze of 50% or less with a thickness of 1 mm after 20-hour immersion in an HCl solution having a temperature of 90° C. and a concentration of 0.1 N.
7. The glass substrate according to claim 1 , which has a haze of 50% or less after 20-minute immersion in an HF solution having a temperature of 25° C. and a concentration of 5%.
8. The glass substrate according to claim 1 , which has a devitrification temperature of 1250° C. or lower.
9. The glass substrate according to claim 1 , which has a content of Fe 2 O 3 of 200 ppm or less as represented by mass parts per million based on oxides.
10. The glass substrate according to claim 1 , which has a Young's modulus of 65 GPa or more.
11. The glass substrate according to claim 1 , which has an area of from 70 to 2500 cm 2 .
12. The glass substrate according to claim 1 , which has a circular shape.
13. The glass substrate according to claim 1 , which has a β-OH of from 0.05 to 0.65 mm −1 .
14. A laminated substrate comprising the glass substrate of claim 1 and a light-shielding film disposed on at least one main surface of the glass substrate.
15. A laminated substrate comprising the glass substrate of claim 1 and a silicon substrate laminated on the glass substrate.
16. A laminate comprising the laminated substrate of claim 15 and another glass substrate stuck to the glass substrate that is a component of the laminated substrate.
17. The glass substrate according to claim 1 , wherein the thickness of the glass substrate is 1.5 mm or less.