May 21, 2001 7AF Dual Fine Grind and Dual Coarse Grind
STRASBAUGH CONFIDENTIAL INFORMATION
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right grind wheel. When the bridge is at the right, the left chuck will be unloaded, conditioned, and reloaded.
Nothing will ever be done with the unused right chuck or with the left grind wheel.
If only the right chuck is being used, the situation is symmetrical.
Note that each wafer that is ground will be ground by only one wheel, never by both.
Editing Recipes, Dress Recipes, and Dress Cycle
It is expected that a grinding recipe will have both halves the same if it is being used in the new modes. That will
allow the same wafer grinding process to run on both chucks. This is not required, however.
Whether you are in Dual Fine or Dual Coarse, you will still have the ability to edit the recipes for coarse wheel
dress/true and fine wheel dress/true. But when you run a dress/true cycle, you will only be able to dress or true
the kind of wheel that fits the mode you have selected. As an example, if you are in Dual Fine mode, you may
select either the left wheel or the right wheel for dress or true, but the dress or true that actually runs will be a
fine wheel dress or true. To dress a coarse wheel you must change mode to either Dual Coarse or Traditional.
You must mount a coarse wheel occasionally to dress/true the work chucks, as is allowed in all three modes.
Another change in the new modes affects the number in the dress recipe that says, “Dress Wheel After Every x
Wafers.” If you use both chucks and you request a reminder after, say, 600 wafers, the reminder will appear as
soon as each wheel has ground 300 wafers. In the Traditional 7AF, placing 600 into the fine wheel dress recipe
will produce the reminder after the right wheel has ground 600 wafers, not 300 wafers.
Other Changes in the New Modes
The filenames are now changed for the grind data in all three modes. Previously, the current data files were
called coarsdat.txt and finedat.txt, which were renamed to names like C38.dat and F38.dat. Now the current
data files will be called leftdat.txt and rightdat.txt and these will renamed to L38.dat and R38.dat. Note that left
and right refer to left wheel and right wheel, not left chuck and right chuck.
In-situ dress of the left grind wheel is not available in the new modes. If requested, it will be ignored.
In the Traditional 7AF, the Bounce Option and the Approach Option apply to the coarse grind if you run a Dual
Grind or a Coarse Grind Only, and they apply to the fine grind if you run a Fine Grind Only. In the new modes,
only one grind wheel ever touches a wafer, so these options apply to each grind on each wheel.
GEM Changes
There is a new variable in the data update, TwoFine, with VID 157, having format U1. This has the value of
machine variable 48 which selects the three modes. VID 27, Grind Type, is changed to match the way this same
information has been changed on the Grind Cycle screen. Its values are:
0 None Traditional 7AF – No grind type chosen yet.
1 Coarse Traditional 7AF – Coarse Grind Only.
2 Fine Traditional 7AF – Fine Grind Only.
3 Both Traditional 7AF – Dual Grind.
4 None Dual Coarse or Dual Fine – No wheel or chuck chosen yet.
5 Left Dual Coarse or Dual Fine – Left Wheel on Right Chuck.
6 Right Dual Coarse or Dual Fine – Right Wheel on Left Chuck.
7 Both Dual Coarse or Dual Fine – Both Wheels on Both Chucks.
In the two new modes, a remote Host command to set the Grind Type will be rejected with an acknowledge
code of 65, meaning, “This command is not supported in the selected grind mode configuration.”
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