Patent ID: 8860227

Claim:
A semiconductor substrate having a plurality of dot marks each formed of a recess portion having an inverted frustum shape, wherein the plurality of dot marks constitutes a two-dimensional code disposed in a rectangular region of 0.25 mm 2 to 9 mm 2 , a diameter W of the recess portion on a surface of the semiconductor substrate is 20 μm to 200 μm, is larger than a diameter w of a bottom surface of the recess portion, and is smaller than a thickness of the semiconductor substrate, a depth of the recess portion of the dot marks is smaller than the thickness of the semiconductor substrate, a side surface of the recess portion has four or more trapezoidal flat taper surfaces, and a taper angle of the taper surface is in a range of 44° to 65° with respect to the surface of the semiconductor substrate, wherein information codes are or character information is written in the semiconductor substrate using the plurality of dot marks.