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SECS II E5-1101 Wafer Map Format

July 20, 2018
Steve DiBartolomeo
Artwork Conversion Software, Inc.

The SECS II binary wafer format (from the SEMI E5-1101 specification) is used to define the location and bin quality of die arrayed on a wafer. This format is used by certain large semiconductor companies (NXP, for example) and is also read/written by the Electroglas family of wafer probers.


The basic structure consists of a byte defining a command followed by a byte containing a parameter. Very often the parameter indicates the number of data bytes to follow. Some parameters are followed by a stream of data bytes; others are not; this depends on the particular command.

Commands and Parameters for the map file header

01 number of items to follow List
41 characters to follow Wafer ID String of Characters
21 bytes to follow ID Type
A9 02 bytes to follow Wafer Flat (2 bytes) 0,90,180,270
21 01 1 byte to follow ORLOC 1:UL 2:UR 3:LL 4:LR
A5 01 Reference Point Select; always set to 01 as this is not used. Only one reference point.
71 08 - 8 bytes follow Reference Point 4 bytes X, 4 bytes Y
41 09 - 9 bytes follow
07 - 7 bytes follow
Die Units - "10^-1*mil"
Die Units - "10^-6*m"
B1 04 - 4 bytes follow Die Size in X coord (first B1)
B1 04 - 4 bytes follow Die Size in Y coord (second B1)
A9 02 - 2 bytes follow Row Count (1st A9)
A9 02 - 2 bytes follow Column Count (2nd A9)
A5 00 Null bin code. Here used to indicate that bin codes are max 1 byte in size.
B1 04 4 bytes follow Process Die Count. tested die plus ugly die.
21 01 1 byte follows Process Axis 01 indicates wafer was probed in quadrant 1.

Commands and Parameters for the Wafer Map

69 06 6 bytes follow RSINF - row start coordinate x,y (4 bytes) and die count (2 bytes). The sign of the die count indicates the direction of travel - negative indicates travel to the left.
A5 04 4 bytes follow BINLT - 4 bytes follow with 1 bin code per byte. A max of 255. If wafer has more than 255 then use A6.
A6 xx xx BINLT - 2 bytes used to indicate number of bytes to follow for wafers with more than 255 devices per row. Both A5 and A6 can be used in the same wafer map file.
69/A5 or A6 RSINF and BINLT repeat until all all rows accounted for.

Bin Codes

The expected bin codes used for die are as follows:

Bin Name    Description
3D Edge Die Geometrically incomplete die along wafer periphery
3C Ugly Die Geometrically complete but bad or with no pattern
3E Skip Die Skipped at probing (within the probing area)
32 Ref Die Reference Die used for alignment
00 Bad Die failed at test/probe
01 Good Die passed at test/probe/inspection

Example of a ROW FORMAT map

SECS II supports three different methods used to enumerate the die position and bin code: ROW, ARRAY and COORDINATE. As all our test files come from EG probers, and because EG only produces ROW format, we are documenting the ROW format.