| 摘要 |
PURPOSE:To supervise a wafer at a low cost and at high speed by a method wherein an identification mark which can be read out with a TV camera is added to a wafer cassette capable of housing two or more wafers. CONSTITUTION:A wafer cassette 3 is constituted by mutually faced parallel side walls 1 and end walls 2 which unite the side walls 1 at both ends. Two or more partition plates 4 are installed at equal intervals at the inside of the side walls 1; one end of the partition plates 4 is bent inward; and a wafer comes into contact with a bent part and is supported by this part. A positioning mark 5 is attached on the end walls 2. The mark 5 is formed by using, e.g., a plastic material whose color is different from the cassette 3. An identification mark 6 which indicates a wafer cassette number or the like is added to, e.g., the end walls 2 of the cassette 3; and the mark 6 is indicated by using a binary code. The mark 6 is identified by making use of a TV camera, for positioning- mark identification use, which is used when the mark 5 is identified; it is possible to supervise the wafers at a low cost and at high speed. |
