MTL Fabrication

Hockey Pucks - Standard Operating Procedure

CORAL Name: --
Model Number: --
Location: --
What it does: --
Introduction: This is an SOP for fabrication of 6"-wafer carriers to be able to use the Endura metal deposition system on 4" wafers.

All labware is TRL "green-dot" contamination level.

Users must be trained in TRL photo and acid-hood, and ICL TMAH-KOH hood.





  1. Get 6" wafers, single polish, and grow about 1/2u thermal oxide.
  2. HMDS then coat with AZ4620 thick resist, spin 60 sec at 4K rpm.
  3. Softbake 20 min @ 90C.
  4. Backside coat w/ same resist/spin parameters as #2 (no HMDS).
  5. Softbake 45 min @ 90C.
  6. Expose in EV1 for 25 sec. you will need to load the mask with the > 5" chuck, maskholder and loadframe, but once the mask is loaded, > switch to a 6" chuck to load and expose the wafer.
  7. Develop, maybe 3-5 min, in AZ440, mildly agitating the solution. Rinse.
  8. Softbake 10 min to dehydrate surfaces.
  9. Re-coat the back side of the wafer with AZ422, final spin 30s @ 4K rpm.
  10. Softbake 10 min.
  11. Re-coat the front of the wafer, on the outer 3/4" only. Do NOT let any resist splash or get into the "open" area in the center of the wafer.
  12. Softbake 30 min.


  1. Put wafer into BOE for twice the time it takes to remove that oxide > thickness, ie if .5 u normally is removed in 6 minutes, use 12 min.
  2. Inspect for defects in the open areas. if necessary, put back in BOE > to remove small oxide remenants in the open area.
  3. Piranha strip the wafers of resist.


  1. Use 6" 25 wafer teflon cassette, green-dot, load wafers pattern "up" at the H-bar end of the cassette.
    Put 7.5" quartz TMAH bath on wire shelf in water bath, fill to level. to cover wafers with TMAH, then cover with poly-pro lid.
    Fill water bath with DI, at least 1/2 full, turn power on, set at 80C. wait 1 hr.
  2. put wafers in boat into TMAH. etch rate at 80C, 20 - 23u/hr. etch > about 1/2 way thru a typical 610u thick 6" wafer, perhaps 13 - 14 hrs.
  3. Measure depth in TRL photo-room microscope. use clean fabwipes to > seperate your wafer, which isn't yet post-TMAH cleaned, from the > microscope stage. etch further if required, otherwise:


  1. Piranha clean etched wafers in same TRL 6" green-dot cassette the TMAH-etch was done in.
    Process completed.
Author: K. Broderick, P. Zamora. 4/00