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ATT Wafer Map Description

This format is unusual in that it does not have any carriage return or line feeds (CR/LF). Instead it is a continuous stream of ASCII characters (including spaces ...)

00          24757-12-D7-A8524353          1903201381081691190210002600      P009875GRD1

A precise number of characters are assigned to each parameter; the parser must keep track of file position and read the number of characters allocated to each parameter.

PositionParameter
1-2File Revision
13-22Lot Number
23-32Wafer Number
43-48Probe Date
49-51Nx (Array)
52-54Ny (Array)
55-57Reference X
58-60Reference Y
61-65Dx (microns)
66-70Dy (microns)

Many of the parameters are optional in which case the parser will find blank spaces for that section of the stream.

After the header section is complete the bin codes appear:

..................................................#PPPPPPPPPPPPPPP#PPPPPPPPPPPPPPPPPPPP.................

The parser must know the length of the row (Nx) in order to properly convert the stream of bin codes into an rectangular array.

The first character of the map data is considered the character for no die (NULL) .

A maximum of 25 grades (for good die) is allowed.

the array dimensions range from 1 to 500 in both X and Y

The array origin is at upper left: 0,0