| CPC C03C 3/087 (2013.01) [B32B 17/10119 (2013.01); B32B 17/10137 (2013.01); C03C 4/18 (2013.01); C03C 21/002 (2013.01); B32B 2315/08 (2013.01); B32B 2457/14 (2013.01); C03C 2204/00 (2013.01)] | 10 Claims |

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1. A supporting glass substrate comprising a compression stress layer on a surface thereof, the supporting glass substrate having:
an average thermal expansion coefficient at 50° C. to 200° C. that is 7 ppm/° C. to 15 ppm/° C.,
an internal tensile stress that is 5 MPa to 55 MPa, and
a depth of the compression stress layer that is 10 μm to 60 μm,
wherein the supporting glass substrate comprises the following compounds in mol % in terms of oxides:
SiO2: 62% to 64%,
Al2O3: 4% to 6%,
MgO: 7% to 8.5%,
CaO: 3% to 5%,
Na2O: 8% to 12%,
K2O: 8% to 12%, and
ZrO2: 0.5% to 2%, and
wherein the compression stress layer is formed by chemical strengthening treatment of the supporting glass substrate.
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