Standard Operation Procedure for Alignment/ Exposure
Purpose: to align the mask to the layers of processing under the photoresist or to simply expose resist through a mask
Location: Pettit and Marcus Cleanrooms
Supplies Needed: mask, mask holder, correct size wafer chuck, tweezers, blue tape (if necessary)
Setup Procedures:
1. Choose the proper exposure wavelength on the mask aligner tool and the intensity measurement tool.
2. Place the sensor of the intensity measurement tool in the center of the mask aligner chuck
a. If possible, measure the intensity through the mask.
i. Place the mask on top of the sensor so that dark space does not cover the sensor
b. If not enough clearfield space, measure with the sensor alone
i. Start a lamp test and not the intensity reading
ii. Calculate the exposure time by taking the dosage found on the photoresist data sheet and dividing by the measured intensity.
c. Be sure to subtract 1.0 mW/cm2 from the measured intensity to account for loss from the mask if not able to measure through the mask
iii. Program the calculated time into the recipe on the mask aligner
Number of Substrates: 1
Process Procedures:
1. Load your mask onto the properly sized mask holder with the chrome side up, and then turn on the mask vacuum
2. Load the mask holder into the mask aligner. The chrome side should now be facing down.
3. Choose the mask aligner chuck so that you sample will not hang over the edges
4. Load the mask aligner chuck
5. Load your sample onto the chuck
a. If your sample does not cover the entire chuck, use blue tape to cover the rest
b. Cut a hole in the blue tape slightly smaller than your sample size
i. Cut the blue tape on a counter or table away from the mask aligner
ii. Do not cut on the chuck
iii. Do not cut the vacuum bladder for the vacuum chucks
6. Load your sample into the mask aligner
7. Align your sample as needed and expose
8. Unload your sample
9. Transfer you sample to the hotplate or oven for a post-exposure back, if needed.
10. Unload your mask