Grind Data Maintenance and Archival
In the past, a single grind data file was maintained for coarse wafers, COARSDAT.TXT, and for fine
wafers, FINEDAT.TXT. If this file exceeded the size that could be sent to a floppy disk, about 1 MB, it was
deleted and restarted. This also meant that if a single floppy disk was used to transfer data, old data would be
overwritten. Grind data files are now archived and stored on floppy disk as C0.DAT, C1.DAT, C2.DAT,
etc. for coarse data and F0.DAT, F1.DAT, etc. for fine data. Files are archived until 20 MB of disk space
remains, then the oldest files are deleted. File names will wrap at 65535. The current working data files are
still COARSDAT.TXT and FINEDAT.TXT. All files are retained in the C:\7AF\EXECODE directory.
This should allow the archival of data for essentially all wafers ever ground on the machine.
Also, there is now a progress indicator for long duration saves to the floppy disk. When storing large data
files to floppy disk, the “Save” button label changes from “Save” to a percentage complete indicator. For
example, on saving data, the button might change from “Save” to 10%, 20% ... 90%, then back to “Save” on
completion.
Fault (Alarm) Logging
Faults (Alarms) are now logged and can be viewed on the Grind Data Screen. A history of up to 100 faults is
retained over power cycling and restarts. The fault list is maintained as an ASCII text file, FLT_DESC.TXT,
with the names of up to 100 of the last faults, most recent first. This feature allows checking for any transient
faults that were cleared in an effort to continue productive operation. The history should be periodically
reviewed to catch any adjustments or facilities that may be getting marginal. It can also be effectively used as
a troubleshooting aid. Note that while troubleshooting, this feature is just as valuable to show what is not
faulting as it is to show the actual faults that do occur.
Wheel Wear Monitoring
Wheel wear is now accurately monitored on the Grind Data Screen. It is calculated when the wheels are
referenced at the right chuck. Therefore, if the wheel is not referenced, the wheel wear indication will be
“Not Available.” Calculations use the right probe to compensate for any variation in chuck height. If wheel
wear exceeds a set number (Machine Variable #25 for coarse and #35 for fine), a notice will be presented to
the operator on entering the Auto Grind Screen. The notice is a request to notify maintenance, but to
continue operation.
Auto Grind Cycle Changes
In previous versions, if a new grind cycle was to be started after completing a previous batch, the operator
had to exit to the Main Screen, then reenter the Auto Grind Screen. Another Auto Grind Cycle can now be
restarted from the Auto Grind Screen without leaving. If an attempt is made to start a grind cycle when
wafers were left from a previous cycle, the request will be refused. The following message will be raised to
please check items that could prevent a Start: “Can not Start! Not Ready: Sel Grind, Reference, Home,
Running or Clear Wafers.”
WARNING! Upon Quitting to the Main Screen, the operator MUST clear any wafers from the machine
as they will not be detected on reentering the Auto Grind Screen!
Following is a list of items changed in the Auto Grind Screen that do not require an extensive discussion
here. The “Halt” button has been changed to “Pause.” If an attempt is made to start a grind cycle without
wafers available, an alarm will be set requesting a new send cassette. For GEM, if remote operation is
enabled, a warning is left on the Auto Grind Screen that the machine can start at any time. Also for GEM, if
the host attempts to change a recipe, the turrets will be locked as to not accept any more material and an
instruction will be given to the operator that this has been done. The turret will be unlocked on starting a new
grind cycle or reentering the Auto Grind Screen. A bug was fixed that would allow a batch of two wafers to
sometimes be ground only on the right chuck. Now, a batch of two wafers will be reliably ground one on the
right chuck and one on the left chuck.
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