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SEMI T1-95 standard specifies the bar code marking on the back surface of silicon wafers.
The character set of BC-412 contains ten digits and all uppercase letters except 'O'. Each BC-412 code also has a start character, a check character, and a stop character.
Every data character has 12 modules. Four of them are fixed-width bars. other modules are spaces. That is how the name BC-412 comes from.
A BC-412 code symbol has a leading quiet zone, a start character, data characters, a modulo 35 check character, a stop character, and a trailing quite zone. Its width ranges between 13.2 mm and 29.04mm including quiet zones.
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