Steppers

• Alignment strategies for the steppers

• Autostep Operation Manual and Software Manual and Training Notes

• Official resist exposure time suggestions for the Autostep

• Autostep Alignment Mark GDS File

RECIPE: Electrodes for graphene on an optically transparent substrate
SUBSTRATE: 170-um double-side-polished fused silica
SOURCE: Melina Blees (McEuen Group)
ADDED: 2/17/13

Rinse wafers with acetone and IPA. Drop P20 on the surface, let it sit for 30s, and spin off. Spin SPR700 1.2 at 4000 RPM for 45s. 115C bake for 90s.
Expose on the auto step for 0.2 s, no focus offset, using the 170um wafer chuck. It will probably give you a focus error; just hit enter and it will try again. Usually it will work on the second or third try, but keep trying.
Develop in MIF726/300 (they're same thing) for 90s. Ideally you should spin dry them, as 170um fused silica really wants to break.

RECIPE: Electrodes for nanotubes on an optically transparent substrate
SUBSTRATE: 170-um double-side-polished fused silica
SOURCE: Chris Martin (McEuen Group)
ADDED: 2/20/13

Scribe wafer identification in lower left corner of wafer flat. N2 Clean 170um Fused Silica Wafer. Apply P20, wait 30 seconds, spin off at 3000/1000/30. Spin SPR-3.0 at 2000/1000/30 (2.9um). Bake at 115C for 90s. Expose 0.55s, and develop in MIF-726 90s. DI stop bath, DI rinse, N2 Dry.

RECIPE: Standard patterns for baseline etches
SUBSTRATE: Standard 500um single-side-polished 4“ Si wafers
SOURCE: Basline etch wafer recipe from AFS:Fellows
ADDED: 2/22/13

Spin P20 at 2000 rpm for 30s, acceleration 2000 rpm/s. Spin OiR 620-7i resist at 2000 rpm for 60s, acceleration 2000 rpm/s. Softbake at 90 C, 60 seconds.

Expose on Autostep i-line stepper. For Si test substrates, exposure time is 0.26s; for SiO2 test substrates, exposure time is 0.5s; for Cr test substrates, exposure time is 0.4s.

Post-Exposure Bake at 115 C, 60s.

Develop in Hamatech. For Si and and SiO2 test substrates, process “300 MIF 60s DP” was used; for Cr test substrates, “726 MIF 60s DP” was used.

• 5x Stepper

• Official resist exposure time suggestions for the 5x

• Alignment Mark GDS File
• Fiducial Mark GDS File

RECIPE: Catalyst lines for carbon nanotube growth
SUBSTRATE: 500-um singe-side-polished y-cut quartz
SOURCE: Zhaohui Zhong (McEuen Group)
ADDED: 2/19/13

Vapor prime with the YES oven (takes ~35 minutes). The resist will NOT stick to quartz using P20 primer. Apply 1813 photoresist spinning for 30s at 4000 rpm, with a 1000 rpm ramp. 
The 5x g-line stepper should be set to “transparent” (switch below the computer). We use a 0.7s exposure time, with an offset of +110. Develop in 300 MIF for 90s.

PROCESS: ASML DUV Stepper Handling of Thin Wafers
SOURCE: Devin Wakefield (Baird Group)
ADDED: 1/8/15

A standard thick silicon wafer can be used as a support for loading thin wafers into the ASML. Important: The silicon support wafer should be thoroughly cleaned and free of particulates and residue on both sides. (Use Piranha or Nanostrip and/or SRD tool.) Using a pipet, place a small amount of water (~quarter sized) on the silicon support wafer. The thin glass wafer can be placed gently on the support wafer, ensuring that the water spreads out evenly between the two wafers. Note: this sealing technique should be practiced in advance before using the ASML tool. Careful sliding of the two wafers across each other helps to remove any bubbles and excess water. Repeat this motion until the wafers are ~difficult to slide, with some resistance. Use nitrogen gas to ensure that the backside of the support wafer is dry before loading into the ASML. You can now run your process. CNF staff (e.g. Dan or Garry) should be present when trying this for the first time as some troubleshooting may be required.

RECIPE: Electrodes for carbon nanotubes
SUBSTRATE: Standard 500um single-side-polished 4” Si wafers
SOURCE: Melina Blees (McEuen Group)
ADDED: 2/17/13

AR3+UV210-0.6, energy 15.5, focus 0.33
Develop in MIF 726 for 60s