To enhance a filling rate of a substrate by increasing relatively simple production steps and to sustain a good workability of substrate arranging work.

A columnar silicon single crystal rod 11 is cut into a right quadrangular prism, and then the arcuate surface at four corners 12a of the right quadrangular prism 12 is subjected to flattening. A corner filling member 13 made of silicon single crystal is then bonded to the flattened four corners 12a through electric insulating adhesive and the right quadrangular prism 12 bonded with the corner filling member 13 is finished to become a right quadrangular prism. Furthermore, right angle ridgeline part 13a of the corner filling member 13 bonded to the right quadrangular prism 12 is bevelled with a width of 1-3 mm and then the right quadrangular prism 12 is sliced to produce a substrate 10. The corner filling members 13 are four arcuate members remaining after the right quadrangular prism is cut out.

COPYRIGHT: (C)2005,JPO&NCIPI