Plade Metal

Preliminary and fundamental remarks:

  • SAFETY OPERATOR MANUAL TO OPERATE ON CMi WETBENCHES  (HERE)

Contents

  1. Introduction
  2. Standards at CMi
  3. Modus operandi

I. Introduction

The baths of the Plade Metal in zone 2 are arranged as depicted in figure 1 and they target etching of Aluminum, Titanium, amorphous or Poly-Silicon and SiO2 selective over Aluminum.

Depending on the application, the bath may be fitted with a temperature adjusting system and with a circulating pumping system to activate etching.

FFR: Fast Fill Rinse (rough rinsing)
TT: Trickle Tank (fine rinsing)
Figure 1: Schematic of the Plade Metal bench
Bath N°4567
ContentsANP

Circulating bath, heating system.
Diluted HF

Static bath, room temperature.
Silox (Pad etch)

Circulating bath, heating system.

Bath filled on demand.  
Poly Etch

Static bath, heating system.

Bath filled on demand.  
ApplicationAluminumTitanium SiOetching
selective over Aluminum
aSi
PolySi

II. Standards at CMi

Important remarks linked to the Silox bath: SiO2 etching in Silox (Padetch) must absolutely be done with the circulating system switched on. If not, it’s mostly probable that etching stops during the process (creation of stopping layer due to the nature of the bath and the presence of the photoresist mask).

Also, it is highly recommended not to do multiple partial etchings in this bath at the risk of stopping the etching due to the creation of the layer previously mentioned. Therefore, etching is to be done in one single shot.

MaterialBath N°ChemicalsMaskEtch rates (nm/min)T (°C)
Al4ANP
H3PO4 85% + CH 3COOH 100% + HNO3 70%
83:5.5:5.5
PR30035
Ti5Diluted HF
HF(49%):H2O
1:50
PR>100020
SiO26 Silox (Pad etch)
NH4F(40%):CH3COOH(97.7%):H2O
4:4:2
PR 40 WetOx
240 LTO
20
aSi, PolySi7Poly Etch
HNO3(70%):HF(49%):H2O
50:3:20
PR73020

III. Modus Operandi

  1. Login on the Plade Metal using zone 2 computer
  2. If applicable, activate the circulating system and the heating system after having checked/changed the set point. If working at room temperature, there is no need to activate the heating system
  3. Adjust the timer according to the etch rate and the wanted result
  4. Load the wafers in one of the dedicated Teflon carrier and put the handle on
  5. Full protection is now required (apron, face shield, chemical gloves) before going further
  6. Once the wanted temperature is reached, open the lid of the bath and gently plunge the carrier into it
  7. Start the timer (with clean hand)
  8. Rinse the gloves and gently clean the bath’s surroundings with a moist paper (several cleanings/rinsings are necessary)
  9. Wait the end of the etching. Remove the individual protective equipment if waiting time is long. Please fill-in a chemical label to inform other users about your running process
  10. If needed, get ready with the individual protective equipment a few minutes before etching is supposed to finish
  11. A buzzer indicates the end; press once on the timer button to stop the buzzer
  12. Open the FFR lid and gently transfer the Teflon carrier from the etching bath to FFR
  13. Activate the FFR button
  14. If applicable, stop the heating system and the circulating system of etching bath
  15. During FFR, rinse the gloves and gently clean the etching bath’s surroundings with a moist paper (several cleanings/rinsings are necessary)
  16. When FFR is finished, switch the Teflon carrier to the Trickle Tank TT
  17. Once resistivity is reached (~12 Mohm.cm), put the carrier in the spin rinser and dryer SRD (the carrier’s handle must be removed)
  18. A recipe is already selected. Just press STOP and the START
  19. When the SRD is finished, get the wafers back and put the carrier where it belongs
  20. Carefully check the cleanliness of the wetbench before taking off the chemical protection (apron, face shield, chemical gloves)
  21. Perform wetbench logout on zone 2 computer

 

Any droplets of any kind MUST be removed from the wetbench before leaving it. Suspicious droplets must be cleared using a moist paper (2 to 3 cleanings/rinsings are necessary) and remaining water droplets must be removed with absorbent paper.