Lithography

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We have several types of lithography available at the nanofabrication facility. 5 x projection lithography on our stepper is for critical dimensions down to 500 nm and for optical lithography needs where critical layer to layer alignments of better than 500 nm are needed. Pieces of 1 cm x 1 cm up to 4" wafers can be used. We can also make grating structures around 200 nm in period over a
1" x 1" area using laser interference lithography. Electron beam lithography can bring resolution down to below 30 nm and alignment accuracy down to 10 nm. Please click on the specific links below for detailed process information using each technique.

 

Contact Lithography

Contact lithography is used for critical dimensions down to 1-2 microns on pieces and exposure areas up to 6" wafers.

  • 3 Karl Suss MJB-3
    • 3" square exposure area
    • IR back-side alignment
  • 1 Karl-Suss MA-BA6
    • 6" square exposure alignment
    • substrate bonding alignment
  • Exposure wavelength for all three systems is broadband (g, h, and i lines).
  • Filtering can be used to eliminate the g and h lines.

Electron Beam Lithography

JEOL JBX-6300FS
Vector Scan Electron Beam Lithography System

  • “Hi-brightness” Thermal Field Emitter Source (ZnO/W) hi-resolution writing at nA’s
  • 25, 50, and 100 kV operation
  • Minimum Spotsize ~ 2nm @ 100kV
  • Maximum scan speed = 12 MHz (0.083us/pixel)
  • 150x150 mm writable area (but can load 200mm wafers)
  • Stage control to 0.6 nm accuracy (λ/1024)
  • Two deflector/objective lens system: 5th Lens (8nm) and 4th Lens modes (25-40nm)
  • Dynamic Focus and Stigmation Control
  • 10 mm/sec maximum stage speed
  • UNIX computer controlled

Projection (Stepper) Lithography

  • GCA 6300 and GCA Autostep 200 i-line systems
  • Pieces (1 cm x 1 cm) up to 6" wafers
  • ~400 nm R&D resolution
  • 15 mm x 15 mm die sizes
  • ~150 nm alignment tolerance

Laser Interference Lithography

  • 1-D lines and 2-D dot arrays

  • 325 nm HeCd laser

  • Lloyd Mirror configuration

  • Pitch control from 206 to 280nm

  • 1” x 1” exposure area

  • ARC and i-line resist process

  • ARC layer removal by O2 RIE etch

  • Uniform, 200nm tall features in resist

Nanoimprinting

  • Thermal imprinting pieces to 4" wafers
  • Master formation into silicon using ebeam lithography
  • UV cureable imprinting with underlayers

Lift-Off Techniques

Lithography Materials (Resists, etc.)

Below is a listing of the lithography materials that we supply for the laboratory.

Wafer Cleaning and Preparation

Preparation of samples for photolithography may require a simple solvent clean, residual organic removal, particulate removal, HMDS pre-coating, or any combination depending on the condition of your wafer. Photoresist removal also depends on the conditions that the resist was exposed to during the processing after lithography. Below are links to the various techniques used in our laboratory for lithography preparation and photoresist removal. These are general techniques with some general guidelines to assist you in developing the process that will suit your needs.

 

Technical and educational staff services are possible through the generosity of the National Science Foundation through support via the NNIN.