The TEL probers output a pair of binary files containing the wafer map data.
LOT.DAT
This is a small binary file that stores lot information, wafer parameters and other data. The map data is help in a separate file. This file is needed to convert a map file because of important information is present in the LOT.DAT file.
The items contained in the LOT.DAT file that we use when converting to another map file format include:
Wafer Name ASCII 12 Bytes Wafer Size ASCII 1 Byte Flat Orientation ASCII 3 Bytes Die Size X,Y ASCII 5*2 Bytes
W-NO-xx.DAT
This binary file stores the wafer map data based on the results of the probing. Each file has the map for a single wafer and up to 50 wafer files can be created for each LOT.DAT file.
Since the wafer.dat file is binary, it is not man-readable. A program must be written to extract the map data and convert it to some sort of ASCII/XML format.
Once you pass the header section, the balance of the file consists of map data. Each device or bin uses 2 Bytes.
Variations?
It is possible that there are some variations in the binary files output by different versions of this machine. We have seen two different documentation for the header part of the WAFER-XX.DAT file.