Difference between revisions of "Optical Lithography Resources"

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! Resist !! Wafer Prep !! Spin !! Thickness !! Prebake !! Exposure !! Postbake !! Development  !! Hardbake !! Lamp !! Notes  
! Resist !! Wafer Prep !! Spin !! Thickness !! Prebake !! Exposure !! Postbake !! Development  !! Hardbake !! Lamp !! Notes  
|-
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| 2002 || Dehydrate on hot plate || 3000rpm || 50μm || 65C 3min 95C 9min || X || 65C 2min 95C 7min || SU-8 Developer X seconds || Optional || Suss1 Ch1 || -
| 2002 || Dehydrate on hot plate || 3000rpm || 1.6μm || 65C 1min 95C 1min || 30s || 65C 1min 95C 1min || SU-8 Developer 60 seconds || Optional || Suss1 Ch1 || -
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|-
| 2025 || Dehydrate on hot plate || 3000rpm || 50μm || 65C 3min 95C 9min || X || 65C 2min 95C 7min || SU-8 Developer X seconds || Optional || Suss1 Ch1 || -
| 2005 || Dehydrate on hot plate || 3000rpm || 5.2μm || 65C 1min 95C 2min || 40s || 65C 1min 95C 2min || SU-8 Developer 60 seconds || Optional || Suss1 Ch1 || -
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| 2100 || Dehydrate on hot plate || 3000rpm || 50μm || 65C 3min 95C 9min || X || 65C 2min 95C 7min || SU-8 Developer X seconds || Optional || Suss1 Ch1 || -
| 2015 || Dehydrate on hot plate || 3000rpm || 17μm || 65C 2min 95C 4min || 120s || 65C 1min 95C 3min || SU-8 Developer 180 seconds || Optional || Suss1 Ch1 || -
|}
|}



Revision as of 12:53, 15 March 2020

Trove of lithography application notes from MicroChemicals covering troubleshooting, procedures, techniques, theory

KNI Photoresists

Photoresists provided by KNI:

  • S1805, 1813, 1818: field standard positive, may be used for liftoff and withstands some acid etching. Designed with lower toxicity materials. (Manufacturer Spec Sheet) Shipley 1800 series 0.5-1.9μm range available. 0.5-3.2μm available from manufacturer. Suitable for multiple applications but not niche optimized as latter resists.
  • AZ 5214: exposable as positive and image reversal negative. Optimized for liftoff processes with negative sidewall profile. Structure is stable to 130°C after postbake. 1-2μm thickness (Manufacturer Spec Sheet)
  • AZ 9245, 9260: Intended for thick positive structures 4-20μm. Lower optical absorption and sensitivity permits tall structures but development is slow. (Product Page)
  • AZ nLof 2020, 2035, 2070: Also optimized for liftoff processes but thicker than 5214 at 2-7μm spinnable. Structures can be made stable to 250°C. High chemical stability, e-beam exposable, but more difficult to remove. (Product Page)
  • AZ 3330-F: medium resolution resist, high thermal stability, optimized for metal RIE etch or plating process environments. 1.0-5.0µm spinnable (Product Page)
  • AZ 4620: improved surface adhesion for etching and plating applications, photosensitivity is broad and low, spinnable to 6 - 20 µm.(Product Page)

SU8 Photoresists are no longer provided by KNI (SU8 Developer IS provided by KNI):


Reminder of lamp intensities:

Suss 1 Exposure Settings

  • Channel 1 is 365nm wavelength at 15 mW/cm2.
  • Channel 2 is 405nm wavelength at 25 mW/cm2.

Suss 2 Exposure Settings

  • Channel 1 is 365nm wavelength at 10 mW/cm2.
  • Channel 2 is 405nm wavelength at 15 mW/cm2.

Reminder of room conditioning:

  • Temperature is specified to 68±1° F in the photolithography and surrounding rooms.
  • Humidity is typically 50% in the photolithography room, KNI is specified to 40-70%. Remember that moving resist coated samples to dryer rooms, they will need to rehydrate over some time period.

Positive Photoresist Recipes

See recipe notes for additional information on wafer cleaning and prep, edge bead removal, and spin curves.

Resist Wafer Prep Spin Thickness Prebake Exposure Postbake Flood Development Hardbake Lamp Notes
S1813 Dehydrate on hot plate 3000rpm 1.6μm 115°C 1min 8-10s - - MF 319 45-60s - Suss1 Ch2 Measured 11/19
Dehydrate on hot plate 5000rpm 1.1μm 115°C 1min 8-10s - - MF 319 45-60s - Suss1 Ch2 Measured 11/19
AZ 5214 Dehydrate on hot plate 3500rpm 1.4μm 100°C 1min 25s - - MF319 60s - Suss1 Ch1 Measured 10/19
AZ 9260 Dehydrate on hot plate 3000rpm 7μm 110°C 145s 60s - - AZ 400K 1:4 3min - Suss1 Ch1 Measured 1/20

Negative Photoresist Recipes

See recipe notes for additional information on wafer cleaning and prep, edge bead removal, and spin curves.

Resist Wafer Prep Spin Thickness Prebake Exposure Postbake Flood Development Hardbake Lamp Notes
AZ5214 Dehydrate on hot plate 2000rpm 1.8μm 100°C 1min 12s 110°C 45-60s 40s MF319 60s - Suss1 Ch1 Measured 10/19
Dehydrate on hot plate 3500rpm 1.4μm 100°C 1min 9s 110°C 45-60s 30s MF319 60s - Suss1 Ch1 Measured 10/19
nLoF 2070 Dehydrate on hot plate 2500rpm 7um 110C 90s 12s 110C 90s - AZ 726 2min - Suss1 Ch1 Measured 12/19

Other Photoresists

  • SU-8 2002, 2025, 2075, 2100, 3025, 3050: epoxy-based negative resist. Optimal for tall high-aspect ratio permanent structures. (Manufacturer Spec Sheet ). Difficult to remove. Spinnable to 1.5-200μm thickness.

Non-KNI Photoresist Recipes

Resist Wafer Prep Spin Thickness Prebake Exposure Postbake Flood Development Hardbake Lamp Notes
SPR 220-7.0 - - - - - - - - - - -

SU-8 Recipes

SU-8 is available in thicknesses ranging from 500nm to 500microns. Remember to use Laurel Spinner 1 and develop in the Wet Chemistry room on the Solvent Bench.

BYU SU-8 Guide

Resist Wafer Prep Spin Thickness Prebake Exposure Postbake Development Hardbake Lamp Notes
2002 Dehydrate on hot plate 3000rpm 1.6μm 65C 1min 95C 1min 30s 65C 1min 95C 1min SU-8 Developer 60 seconds Optional Suss1 Ch1 -
2005 Dehydrate on hot plate 3000rpm 5.2μm 65C 1min 95C 2min 40s 65C 1min 95C 2min SU-8 Developer 60 seconds Optional Suss1 Ch1 -
2015 Dehydrate on hot plate 3000rpm 17μm 65C 2min 95C 4min 120s 65C 1min 95C 3min SU-8 Developer 180 seconds Optional Suss1 Ch1 -

KNI Developers

These developers can be used on the Develop Bench in the Optical Lithography room or on the BASE Bench in the Wet Chemistry room:

  • AZ 726 MIF: 2.38% TMAH-based, pre-diluted (ready-to-use) and slightly further diluted only when the application requires it. Contains surfactants to improve development uniformity, so avoid stirring. MIF identifies the developer as 'Metal Ion Free' as it does not contain potassium as in KOH-based developers, it is based on TMAH, an ammonium salt, which prevents metal contamination of semiconductors. 726 is a recommended developer for almost all AZ resists MicroChemicals Development Application Note
  • Microposit MF 319: (Metal-Free) TMAH: 2.45%, Polyalkylene glycol <1%, pH: 13. Paired to Shipley/Microposit 1800 series resists, S1805,S1813,S1818 MSDS
  • Microposit CD-26: TMAH <5.0 % , pH 13, Also 1800 series targeted, no additional surfactants.
  • AZ 400K: KOH-based. "The recommended dilutions for the AZ® 400 K or AZ® 351 B for most of the processes are developer concentrate : Water = 1: . For very thick resist films, up to a 1:3 ratio can be applied [with lower contrast], with a very fine (sub-µm) structures, a 1:5 or 1:6 ratio can support a high resolution using thin resist films." Ref: MicroChemicals Development Application Note Users can adjust dilution for accuracy and length of time they will tolerate.
    • Critical note on KOH use: "Incompatibilities between MIC and MIF Developers Even small traces of TMAH-based metal ion-free developers such as the AZ® 326 MIF, 726 MIF or 826 MIF) can significantly reduce the development rate of metal ion-containing developers (such as the AZ® 400K or 351B). If both types of developers are used, extremely clean work is to be ensured to prevent mutual contamination even in the ppm range, such as in the dispensing system or developer containers." Ref: MicroChemicals Development Application Note
  • Microposit 2401: Legacy developer


SU-8 developer can ONLY be used on the SOLVENT Bench in the Wet Chemistry room:

  • SU-8 Developer: (Organic Solvent Solution) 1-Methoxy-2-propanol acetate, >99.5%, Synonym propylene glycol monomethyl ether acetate 2-Methoxy-1-propanol acetate, <0.5%. MSDS Paired to SU8 series resists.


Surfactants

Surfactants were developed and added in the 1980s to photoresist developers to combat photoresists' hydrophobic surfaces which cause "hot spots" of fast development. They reduce the surface tension and improve wetting (giving homogeneous development). The common drawback of their inclusion is foaming and an oily nature which makes them incompatible with some agitated processes. Surfactacts also change development speed since they coat photoresist surfaces and inhibit the dissolution reaction. As such exposure-development times must be adjusted and while contrast is improved, resolution may be lost. See here for more in depth discussion: The Lithography Tutor: Photoresist Development

Addtional Photolithography Resources