PMGI SF 6

About this Process
Process Details
Equipment	PMGI SF 6
Technology	Lift-off

PGMI SF 6 is a lift-off resist polydimethylglutarimide (PMGI) that is desinged for lift-off process and sacrificial release layers. It is used in combination with conventional photo resist to create and undercut or step feature facilitating clean and easy liftoff minimizing, or eliminating stringers and edge roughness. PGMI dissolves in Remover PG. Acetone can be used to dissolve the PR layer and do the initial liftoff but Remover PG must be used to remove the SF 6. It is always recomened to do a double bath of Remover PG followed by IPA, and then water rinses.

Announcements

On 1/18/22 our contact aingers were re calibrated. This may increase the exposure time on those tools by up to 22%. This wiki page will be updated after we have verified the new exposure information.

Procedure

Notes

• These recipes are for 3500Å (2000rpm open lid and 1500rmp closed lid) of SF6, allowing you to lift off upto 2625Å of metal.
• These are all for Si. Other materials will have different reflections and this may impact the required exposures.
• You can spin thicker or thinner but you may need to adjust your develop/exposure time and this will affect your minimum distance between features.

Process

• Spin SF 6 on Spinner CEE Apogee
  • 2K for open lid for 3500Å
  • 1.5k for closed lid for 3500Å
• Bake for 5min at 190°C, lid down on hotplates in 1440C

Contact Aligners

These recipes are for 2um spacing between features.

SPR 220 3.0 process

• Spin SPR 220 3.0
  • 3K spin
  • 3um on TEL Mark Vz Coater
• Bake at 115°C for 90 seconds
• Expose for 7 seconds
• Bake a 115°C for 90 seconds
• Develop
  • 30 sec AZ 300 spray develop on the TEL
  • DP 25-25 726 puddle develop on the CEE developers

1813 Process

• Spin 1813 at 4K spin (recipe #4 on CEE spinners)
• Bake for @110°C for 4 min on hotplate
• Expose 4.0-4.5 seconds with 20 mJ/sec broad band light
• Develop
  • 30 sec AZ 300 spray develop on the TEL
  • DP 20-20 726 puddle develop on the CEE developers

Stepper

• Spin SPR 955
  • 0.97NV on TEL Mark Vz Coater
• Expose, 0.3 sec, -5F
• PEB 110°C 90 sec
• Develop
  • 25sec AZ 300 spray develop on the TEL
  • DP 15-15 726 puddle develop on the CEE developers

Characterization

Spin Curve

PMGI SF 6 spin curve on CEE 100.

Affects of develop time

1813/LOR System

Spray Develop

Puddle Develop

Exposure Matrix

Focus Matrix

Limitations

The metal should only be 75% of the thickness of the lift-off resist. For 3500Å of SF 6, your metal stack should be 2625Å or thinner.

Data Sheets

[Technical Data Sheet]