AZ

AZEdit

1. Deposit:

primer: Microposit

spin 5” @ 1000rpm (rise time 10”)
spin ~30” @ 6000rpm (rise time 5”)     ~10 nm layer

resist: AZ52xx

dispense 3 mL for 3 inches wafer
Dispense at constant rate in the center of the wafer, and do not empty the container to avoid bubbles.

spin 1000 rpm 3” (rise time 10”) to spread the resist over the wafer
spin 60” for a uniform coat (rise time ~2”)

2. Soft bake (solvent evaporation):

Hot plate 45’’ - 1' @ 100 °C

Wafer must be cooled down before exposure. 
DNQ-based resists (= almost all AZ®positive and image reversal resist) require a certain water content during exposure in order to subsequently attain a high development rate. A high development rate is a requirement for a high contrast. The rehydration time to attain an equilibrium water concentration in the resist is diffusion-limited and increases quadratically with the film thickness: Thin (< 2 μm) resist films only need seconds for this process steps which makes an extra delay redundant.

3. I-line Exposure: (10mW/cm2 avec MJB4 - oct 2008)

standard parameters   50 mJ/cm2 (/1.5µm)
for fine resolution        30 mJ/cm2 (/1.5µm)

This should be integrated over the whole spectrum of the mask aligner, weighted by the resist sensitivity

Note the resist becomes transparent when exposed (right figure)
             

4. Post-exposure bake   (for reversal only):

standard parameters   2’ @120ºC (setpoint 125°C in SPEC / LPN cleanroom hotplates)

Check the hotplate temperature with a thermometer.

To be increased if lowering the first exposure dose.

5. I-line Flood Exposure  (for reversal only) :

> 200 mJ/cm 2/µm   (~ 20’’ au MJB4 )

6. Development:

developer: AZ531B or AZ 400K or MIF 726

Development at ambient temperature in diluted developer: ODI + AZ351B (4:1)
base de temps pour le MIF 726: 30’’

Procedure for first determination of development time: perform a flood exposure and develop. The film thins in the developper, which provokes visible interference patterns and irisations. When these patterns dissapear, this determines the development time.
Add 10% over-developping for positive process,
Add 30% for negative process in order to get a good undercut (as the undercut developps after the pattern is completely dissolved)

Rinse: ODI
to stop development, under water tap ~1’-2’