BPC7

BPC7Edit

jeudi 11/02

desox HF:ODI, 1:20, 1'
rinse ODI 1'

lundi 15/02

• Litho BPC7 1st step

bake wafer > 10' @ 110°C (solvent evaporation)
spin S1813 60" @ 4krpm
bake 2' @ 110°C
Expo 150mJ/cm2 @ 365nm, Vacuum contact -> 15" @ 10mW (fluctuates 10.2-10.5)
Dev MF319 55" @ 19.4°C, rinse ODI 60" beaker + 30" water tap
(decide to increase dev time because last time there were resist residues on some resonators)
/!\ Note rinsing is critical also, because developper contains resist residues, 
and few nm resist can block subsequent etching

Globally patterns are nice.
Resist on the bobin seems thinned (see below on the left)
From place to place the Al layer seems already etched, but mostly not (see below on the right)

• Al-Etch . Peremption 2002 (!!)

in tall beaker with magnetic agitator 
+ manual movement (slow, repetitive, from back to front) 

after 2' the whole wafer seems to be etched
leave 4' to insure etching of small patterns, rinse ODI in beaker + 1' water tap

Same time as wafer BPC5 (january) -> OK for reproducibility
In fact, after etching, I realize that it was resist residues that I took for Al etched (below, same chip as above)
It seems the wafer was not clean enough after development. Now we can see stripes of Al not etched + residues in between arms of the bobin.
 left: after the 4' Al-etch                                                     right: after adding ozone 2' + Al-etch 2'

I should have done (adjust next time)
-> rinse in fresh developper for 5"
-> rinse in ODI + water tap for at least 1'
-> clean ozone for 2'
-> hard bake

For now I leave it like that because some patterns are beginning to be a little overetched

mardi 16/02

• Resist strip

remover PG 20'

giovedi 18/02

• Baking BCB

bake BPC7 at 200°C for 1h

Litho step 1b

bake wafer 5' @ 110°C (solvent evaporation)
spin AZ5214E (new bottle, per. ) 60" @ 4krpm
bake 1' @ 110°C
Align+Expo Layer 1B 47.5mJ/cm2 @ 365nm, Vacuum contact+Alignment check -> 5" @ 9.5mW
bake 3' @ 120°C
Flood expo 45"
Dev AZ developper:HDI 1:2 1min50sec +rinse ODI 60" beaker + 30" water tap

Etch Ar 500v 130mA 1min40sec
Evap Ti 20nm @ 0.1nm/s
Evap Au 10nm @ 0.1nm/s  
Lift-off Remover PG @70deg overnight + ultrasound 8min +rinse ODI 60" beaker + 30" water tap

Litho 3rd step

• LOR20B+AZ5214 Mask

bake the wafer @ 110°C for water removal
spin TI prime @4krpm, bake 1min @110deg
tape the wafer on blue clean room tape, cut to a ~3" size
dispense 1-1.5mL resist slowly from a pipette (well centered on wafer)
2" @ 300rpm acc 250rpm/s
3" @ 800rpm acc 500rpm/s
60" @ 1500rpm acc 500rpm/s
Cut the edges of the spun resist on all sides of the wafer before untaping
bake 5' @ 170 °C
spin AZ5214 60" @ 4000rpm
bake 1min @110deg
Align+expo Layer3 dose 5" (47.5 mJ/cm2) +Vacuum contact +Alignment check.
bake 3min @120deg
flood expo 45"
develop in AZ Developer 1:2 HDI 2min + rinse water + water tab
develop in MF726 for 1min15sec (tabulated 1min18")

Result

Plasma O2 0.2mbar 100W 2min

• Evap bridge

Etch Ar 500v 65mA 10sec
Evap Ti 5nm @ 0.2nm/s
Evap Al 250nm @ 1nm/s  
Lift-off Remover PG @70deg overnight +rinse ODI 60" beaker + 30" water tap

Result

Litho 4th step

• spin MAA / PMMA bilayer

  jeudi 31/03

- spin MAA8.5 EL10 (batch 14020103, exp. 01/2015) @ 2000rpm for 60" + 2" @ 8000rpm acc 4k
- bake hot plate setpoint 180°C, 5'
- spin PMMA A4 (batch 12060427, exp. 7/1/2013) @ 4000rpm for 60"
- bake hot plate setpoint 180°C, 15'
- spin UV III (Vivien bottle) @ 4000rpm 60"
- bake hot plate 140°C, 90"

ellipso:
MAA = 545 +/- 5nm
PMMA = 185 +/- 10nm

• dice

Cut wafer in 2, and take 1/4

-