A few tips for using alignment marks
1. Suppose you move to a mark (with mvsp perhaps) but you do not see the mark in the SEM window. In desperation you can look around in the vicinity with the command
spiral
which simply moves the stage around in a square spiral of increasing radius until you give up. Look at /home/pg/bin/spiral to see how it works.
2. You can measure the rotation of your wafer by using the alignment microscope, but you can measure rotation much more accurately using the ebpg itself. The command
test_rotation
or
testrot
will prompt you to find two alignment marks, presumably on the same axis. The rotation of your substrate will be calculated and displayed. You might find this handy if you have a very small substrate with marks that are too close together.
3. You can test the alignment process without writing a pattern, by including the option "--skip" on the job line of the wrapper script. For example
myjob.job 3 0 $ul $ur $lr $ll --skip 2>&1 | tee -a logfile.log
4. The most common mistake is getting the corners confused. If the exposure aborts due to a very large scaling or rotation error, check the mark positions with
echo $ul
echo $ur
etc
Also, make sure that the order of the marks on the 'job' line matches the order of the marks in cjob.