XR-1541.006 (FOx-12) Recipe

Application

tone

negative 

special

Superior edge roughness

reference

J. Vac. Sci. Technol. B. 16 (1998) 69 - 76

spincoat

202 - 128 nm @ 1000 - 6000 rpm  thinner layers can be obtained at Karl Suss spinner WITH lid closed:
 61 - 44 nm @ 1000 - 2000 rpm or by diluting with MIBK (see spincurve below)

prebake

2 minutes on hotplate @ 150 °C  

2 minutes on hotplate @ 220 °C

 

or

 

30 minutes in vacuum at room termperature

exposure

about 500 µC/cm2 @ 100 kV

development

1 min. in MF322  

15 s in MF322 : demi-water = 1 : 9  

15 s in demi-water 

Results: Spincurves

Work done in FOx-12

15 nm single pass line in 44nm thick FOx-12, exposed with spot 21nm_740pa_400um_100kv and dose 5460 µC/cm2 @ 100kV

20nm dense lines and spaces (single pass lines) in 50nm thick FOx-12, exposed with spot 21nm_740pa_400um_100kv and dose 6970 µC/cm2 @ 100kV

Etchrates of FOx-12 resist in different plasmas in comparison with HPR504

GAS 1: SF6/He plasma on Leybold Z401:

 SF6

 12.5 sccm

 He

 10 sscm

 Pressure

 10 µbar

 P

 40 W

 Biaspotential

 -60 V

 

GAS 2: CHF3/O2 plasma on Leybold Z401S

 CHF3

 50 sccm

 O2

 2.5 sccm

 Pressure

 7 µbar

 P

 50 W

 Biaspotential

 -350 V

 

GAS 3: O2 plasma on Leybold Z401S

 O2

 20 sccm

 Pressure

 3 µbar

 P

 20 W

 Biaspotential

 -200 V

 

Etch rates (nm/min):

Gas 1

 Gas 2

 Gas 3

 HPR504

 51

 16

 29

 FOx-12

 29

 36

 0.6

FOx-12/HPR bilayer resist combination

HSQ can also be used in a bilayer combination with hard baked HPR for high aspect ratio nanoscale e-beam lithography.

For this reason a few steps should be added to the processing flowchart:

  • After spincoating and baking HMDS and before following the FOx-12 flowchart HPR504 should be spincoated (5000rpm 937nm) and baked on a hotplate at successive 100, 200 and 250 0C, each temperature for 2 minutes.
  • After development of the FOx-12 resist the HPR is etched in above mentioned O2 plasma (gas 3).

A few examples of work done in a bilayer resist of FOx-12 and HPR

80nm multi pass lines (10 passes) written in 44nm thick FOx-12 on top of 937nm thick HPR, exposed with spot 21nm_740pa_400um_100kv and dose 290 µC/cm2 @ 100kV

80nm multi pass lines (10 passes) written in 44nm thick FOx-12 on top of 635nm thick HPR, exposed with spot 21nm_740pa_400um_100kv and dose 990 µC/cm2 @ 100kV

26nm semi-dense lines written in 30nm thick FOx-12 on top of 155nm thick HPR, exposed with spot 21nm_740pa_400um_100kv and dose 815 µC/cm2 @ 100kV

40nm dense lines and spaces (1:1) written in 30nm thick FOx-12 on top of 129nm thick HPR, exposed with spot 21nm_740pa_400um_100kv and dose 1646 µC/cm2 @ 100kV

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