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Most Common AIF Errors

July 6, 2001

When designers initially start creating AIF files for input into Artwork's tools such as Wirebond, Bondgen and FA4ST they often make mistakes that prevent the programs from using the data.


Since these "problem" files make it to our offices, I've compiled a list of the most common errors that we run across.

Missing Section Header

The designer forgets to use one of the required section headers. The one we have seen missing the most is the [netlist] section.



dp50=SQUARE 50

[NETLIST]                                   <--- sometimes forgotten
clock5    1   dp50 xxxxx   yyyyyy   A5

Pad Stack Definition doesn't match

The padstack name in the [PADS] section must match the name used in the [NETLIST] section. This is case sensitive!

dp50=SQUARE 50

clock5    1   DP50 xxxxx   yyyyyy   A5   <--wrong case!

Spaces in Net Names

Net Names may not have spaces in them. If your original net names have spaces use the underscore ( _ ) character to replace them. When the AIF reader sees the space it thinks it is reading the next field.

clock skew 55    1   dp50 xxxxx   yyyyyy   A5   <--Wrong

clock_skew_55    1   dp50 xxxxx   yyyyyy   A5   <--OK

Net Names Run Into Die Pad Number

Sometimes the net name "runs" into the die pad number. This occurs when you have not set your net name column wide enough in Excel. We have also seen this occur for coordinates that run into the next field.

clock_skew_551   dp50 xxxxx   yyyyyy   A5   <-- Wrong

clock_skew_55 1   dp50 xxxxx   yyyyyy   A5   <-- OK

Ambiguous Use of Signal Names

Die pads which are electrically connected together (for example, that are all bonded to the same ring) should have identical net names.

Some designers feel the need to give these enumerated net names such as VDD1, VDD2, VDD3 when in fact they should all be VDD.

vdd#1  2   dp50  xxxxx yyyyyy    -   <-- Wrong
vdd#2  12  dp50  xxxxx yyyyyy    -
vdd#3  22  dp50  xxxxx yyyyyy    -

vdd    2   dp50  xxxxx yyyyyy    -   <-- Right
vdd    12  dp50  xxxxx yyyyyy    -
vdd    22  dp50  xxxxx yyyyyy    -

While using the numbered VDD's will not crash the AIF reader it will cause you problems later when using these files to create netlists in the package design tool and will also mess up routines that enumerate for you the number of power and ground nets.

What's in a AIF File
Describes the basic sections of the AIF file and their syntax.
  Creating an AIF file with Excel
Describes how to create an AIF file using MS Excel.
  Creating an AIF from GDSII
Describes the program, SmartDie, used to read, scan and convert a pad ring layer into AIF.
Sample AIF Files
Shows simple and complex AIF files and their associated layout.
  Common Errors
Describes the most common errors made when creating an AIF File.
  Multi Die AIF
A special version of AIF II designed to contain multiple die (MCM)
Amkor Adopts AIF Format
Amkor Technology, the world's largest contract assembler has adopted AIF as its preferred format for exchanging die data ...
  Read AIF into Cadence APD
You can read an AIF file directly into Cadence APD with this SKILL program. All intelligence is transferred.
  Wire Attach Offset
describes how to support a wire attach point offset in AIF without breaking a proper AIF reader ...
Importance of Net Names!
An explantion of the value of adding net names to your die pad list ...
  How to Extend AIF
Writing your own AIF tools? How to add your own extensions so that you won't break other's AIF parsers.
AIF Viewer web page..

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