MLA150 - CAD Files and Templates

Alignment Marks

Any cross shape with a 10-50µm wide line will work for automatic alignment. By default, system expects this cross shape to cover/extend beyond the entire field of view of the chosen microscope, which are the following sizes:

Alignment mark sizes should be larger than the following

Camera	Field of View
Low Mag.	640 x 480 µm
High Mag.	190 x 140 µm

For the best alignment, the High-Mag camera is preferred, so a Cross of ~250µm x 200µm (50µm larger than the high-mag. FOV), with line width of 20µm would be acceptable.

The coordinates to the center of each mark should be known, with respect to the origin (0,0) of the CAD file to be exposed.

Crosses can be exposed by the MLA150 itself (good for full wafers with open areas on the edges), or can be included in your CAD file (good for cleaved pieces without much unused edge area).

Resolution and Calibration Patterns

Resolution test patterns and Alignment Verniers can be found on the local MLA150 computer in the .../Users-Nanofiles/a-Public Templates folder.

Has line-space resolutions from 65nm → 1.0µm. Isolated versus dense lines are shown via lines protruding further beyond the dense patterns. The text indicates the "period" - twice the line/space width.

You will find two such files on the tool:

• UCSB_MLA150_Calibration_pattern_v5_UnitCell.gds - a single unit cell of the pattern, used for focus-exposure matrix (series)
  • Image Size for the Unit-Cell: 500 x 650µm for stitching the alignment crosses of adjacent die.
• UCSB_MLA150_Calibration_pattern_v5_AcrossWafer.gds - covers a 100mm wafer, used for alignment vernier testing.

Other CAD File Templates

See the Calculators + Utilities > CAD Files & Templates page for other useful CAD files, such as overlay verniers, vented fonts etc.