UPDATES:
1. Substrate Clean – solvent clean, acetone, IPA
2. PECVD oxide – GSI 200nm
3. AS200/620-7i lithography module/ASML-DUVa). HMDS vapor prime
b). BARC apply, bake
c). 620-7i/deep UV resist apply
d). soft bake, hotplate
e). exposure
f). develop – Hamatech4. BARC etch – Oxford 82
5. Oxide RIE – Oxford 80, CHF3/O2
6. Photoresist removal – Oxford 80
7. Silicon RIE – PT770 or PT720 Cl2 chemistry timed etch
8. Profilometry/interferometry
9. Oxide removal – Buffered oxide etch
10. Anti-stiction application – FOTS – MVD tool
1. Substrate clean – Hot Piranha Hamatech Wafer Clean (Prog 1)
2. Sputter deposit 20nm chrome – CVC sputter system, use rotating chucks for improved uniformity
3. Lithographya. either ASML (for features down to 300nm)i. HMDS vapor prime – YES oven
ii. apply BARC – AR3-0.6, 4500rpm, 45sec, bake at 205ºC 90sec
iii. apply resist – UV210-0.6, 4500rpm, 45sec, bake at 135ºC 60sec
iv. expose – 25mJcm-2, bake at 115ºC 60sec
v. develop – Hamatech Prog 1 (MIF726, 60sec)
vi. ARC etch – Oxford 80, “AR3 ARC etch” recipe, 70secb. or AS-200 (for features down to 800nm)
4. Cr etch – Trion
a. Clean - 10min O2 with sapphire wafer in
b. Clean - 10min N2/Cl2 with sapphire wafer in
c. Season - 10min using “Standard Cr etch” recipe with CR target in
d. Etch template - 3min Cr etch using “Standard Cr etch” recipe (check mask has cleared)
e. Immediately after etch: DI H2O rinse, N2 dry (to prevent damage by Cl from etch)5. Inspection – optical microscopy or SEM
6. Photoresist removal – Oxford 80, 2min O2 clean
7. Quartz etch – Oxford 82,a. Clean – 10min O2
b. Clean – 10min N2/Cl2
c. Season – CHF4, 10min
d. Template etch – CF4, 3min (→ about 80nm depth)8. Profilometry measurement
9. Inspection – optical microscopy or SEM
10. Cr strip – wet etch (use 10min Cr stripper in chem hood, Hamatech does not work)
11. FOTS (anti-stiction) application – MVD 100, 2min preclean, 10min reaction time, 10 purge cycles.
1. Oxford 81, 3min O2 clean with 5sccm CF4, both sides
2. Hamatech Hot Piranha – Prog 1 (Wafer clean) or Prog 2 (Mask clean – more thorough)
3. Reapply FOTS as necessary – check with contact angle measurement
Note that after coating a template with FOTS, the template should be good for ~100 imprints. You can safely use acetone, DI water, and the N2 gun on an FOTS-coated template for clearing away larger particles. The first imprint of a given run will almost always be a throwaway, as it cleans out any smaller particles still on the template. For this reason, it's a good idea to use a thicker resist layer for the first imprint.
- Imprint substrate clean – Hamatech
- Apply NXR-1025 thermoplastic resist – 1500rpm, 60sec, 250nm (thickness should exceed maximum protrusion height of the template)
- Bake at 150C for 1 min. on hotplate
- Imprint – NX-2500, 200psi, 120C
- Mold removal
- Pattern transfer – RIE of residual layer- Oxford 80, O2 chemistry
- Substrate etch – TBD
- SEM/AFM inspection/measurement of CDs, bias, etc.
Note that the first imprint of any run will almost always be a throwaway, as its resist cleans out any small particles from the template. For this reason, it's a good idea to use a thicker resist layer on the first imprint.
Preparation:
Recipe for thicker resist for template cleaning (1st imprint):
Recipe for standard imprints:
Imprint:
Pattern transfer into substrate:
(A) Spinner bowl in the e-beam resist room, lined with beta wipes. Note the lights are off for the resist spin. (B) Hot plate in the e-beam resists room, used for primer bake. (C) Putting the plastic film back in place after IPA cleaning. The magnets hold it in place, but be sure it’s flat. (D) Ready for imprint. The stack from the bottom is: small plastic sheet, face-up wafer with resist, face-down template, larger plastic sheet.