PURPOSE: To enable defect in the level of assembling IC chips to be determined visually with easiness and to improve workabilities, by displaying characters, numerals, symbols, marks, or the combination thereof on the reverse of a wafer.

CONSTITUTION: In the region 13 corresponding to each IC chip on the reverse 11 of the wafer whose pattern has been formed, a name 14, lot number 15, and one pin mark 16 of each IC chip are displayed. These displays are performed, by writing the name, lot number and one pin mark, etc., in the reverse position corresponding to each IC chip through a laser marking method, etc., at such a time point of giving no effect to other processes as the one before a dicing process. A line width is about 50-100μm, and a character size is about 0. 5-1 mm in four sides, and further, the size capable of nearly confirming the character by the naked eye is desirable. But, if circumstances require, the line width may be about 10-50μm, and the character size may be about 0.1-0.5mm in four sides, so that they can be confirmed easily by an optical microscope. Thereby, a defect in the simple level of assembling the IC chips can be determined visually with easiness, and the workabilities in experiments and evaluations can be improved too.