PMMA A4 4krpm

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About this Process
Process Details
Equipment PMMA A4 4krpm
Technology Electron beam lithography
Material PMMA
Chemicals Used MIBK
Date Created 5/16/2016
Authored By Kevin Owen

PMMA A4 4krpm is a standard process using PMMA A4 to produce a 200 nm thick mask with electron beam lithography.


Photoresist spin and soft bake

The photoresist spin and bake should be performed at the E-Beam Spinner/Hot-Plate Bench.

  1. Start the bench and let the hot plate heat to 180°C
  2. Mount the correct chuck, depending on sample size, onto the spinner
  3. Load the 4krpm 45sec recipe for 4" samples
  4. Load sample and check centering
  5. Dispense PMMA A4 using a pipette and click Start Process
  6. Once the spin is complete, transfer to hotplate at 180°C for 180 sec


Exposure is performed on the JEOL E-Beam. Exposure dosage will depend on the materials on the sample and feature size. The standard exposure on silicon is 650 μC/cm2. For an oxide film, this can be increased to 675 μC/cm2. For large or varied features, the tool supports proximity correction.

Feature Substrate material Recommended dose (μC/cm2) Minimum feature
Proximity corrected Silicon 650
Proximity corrected Silicon dioxide 675
Isolated lines Silicon
Isolated trenches Silicon
For assistance characterizing exposure dose, please create a helpdesk ticket.


PMMA is developed with MIBK in the E-Beam Solvent Bench.

  1. Develop sample in a 1:3 mixture of MIBK:IPA for 60 sec
  2. Rinse sample in IPA for 30 sec
  3. Blow the sample dry with a N2 gun


Describe what this recipe can be used for (e.g. feature size limits).


Add thickness map for 4" wafer