Maskless Aligner (Heidelberg MLA150)
Work In Progress
This article is still under construction. It may contain factual errors. Content is subject to change.
The MLA150 allows for arbitrary direct patterning of I-Line photoresists, directly from an uploaded CAD drawing/file (GDS, DXF, CIF etc.). The system uses a digital micromirror device ("DMD", an array of MEMS mirrors) for patterning the exposure light-field, to programmatically expose digitized patterns directly onto the sample - no glass photomasks/reticles are required.
The system has a continuous, automatic autofocus, using either a pneumatic or optical detection. This enables lithography on non-planar or curved substrates. We also have the high-aspect ratio (variable/long focal length) option installed for very thick (~70µm) photoresists.
Depending on the exposure options and write area, the MLA is able to expose a 100mm wafer in about 30min, and achieves minimum features sizes around 0.5µm, with overlay/alignment accuracy better than 200nm. Arbitrary drawings can be exposed onto any feature located on the microscope.
Greyscale lithography is capable of producing repeatable slanted or tapered structures in photoresist or photo-active dielectrics like SU-8.
- Wafer size:
- Wafer / substrate thickness: Max. 9mm.
- Thicker is possible, contact supervisor.
- Exposure optics:
- Digital micromirror device (DMD)
- Laser #1: 375nm
- Laser #2: 405nm
- Alignment Accuracy: ≤ 200nm
- Additional manufacturer options:
- High-resolution option (Write Mode 1)
- Extended Focus Range
- Variable Focal Depth
- Optical (laser) Autofocus in addition to Pneumatic Autofocus
- Part 1: Overview and basic usage
- Part 2: Focus Exposure Matrix (FEM)/Series
- Part 3: Local "Field" Alignment
- Recipes > Lithography > Maskless Aligner MLA150
- Starting recipes for various I-Line photoresists