Glass substrate and method for manufacturing glass substrate

A glass substrate for manufacturing a semiconductor device, wherein, in a case in which one surface is directed downward in a vertical direction and a first position, a second position, and a third position on the one surface on an outer side in a radial direction with respect to a center point of the glass substrate are supported by supporting members, a lowest point as a position where a height in the vertical direction is the lowest on other surface is positioned in a circular central region on an inner side in the radial direction with respect to the first position, the second position, and the third position when viewed from the vertical direction, a center of the central region is a center point of the glass substrate, and a diameter of the central region has a length of ⅓ of a diameter of the glass substrate, wherein,

• assuming that a larger value of maximum deflection amounts is Tmax, the maximum deflection amounts including a maximum deflection amount in a case in which the one surface is directed downward in the vertical direction and the first position, the second position, and the third position on the one surface are supported by the supporting members and a maximum deflection amount in a case in which the other surface is directed downward in the vertical direction and the first position, the second position, and the third position on the other surface are supported by the supporting members, a thickness of the glass substrate is D, and a Young's modulus of the glass substrate is E, Tmax·D3·E/1000≤20 is satisfied.