Mask Order

I-Line Stepper Masks (GCA Stepper and GCA Autostepper)

Some things you might need to know

• UCSB standard stepper frame
  • Important! Read the instructions before you start.
  • This Ledit file includes frames for 1, 2 and 4 fields on a single plate. You do not need to place each layer in this file, but it will be a good visual display for each layer when you try to put in coordinates for each layer.
• Mask vendor: Photronics. Please contact Grace Law (glaw@photronics.com) for mask order.
• File:QUOTE UCSB25940-BH-05R (02-20-13).xls.

ALTERNATE ON CAMPUS VENDOR (24-48 HOUR TURN AROUND)

NCF Mask Service Media:NCF_mask_writing.pdf.

• Fill out online form: http://maskwriting.cnsi.ucsb.edu/form.php
• Email mask file to: Peter Duda duda@cnsi.ucsb.edu

Necessary files for mask order

• GDS file for each layer
• Instructions for the placement and coordinates for each layer on the mask plate (example)
  • You can specify spec. of the mask, position of each layer, and polarity here.
    • A note on polarity: If a layer is specified as "negative," what you have digitized is clear on the mask. If the layer is "positive," what you have digitized would be dark on the mask.
• Mask order form (example)

DUV Stepper Masks

Please start by going through these slides

The DUV Stepper alignment mark may be something you put on i-line stepper masks if you plan to do pieces. The alignment is frequently ~30nm so I have a new Vernier that you can try. I have tried it myself yet. 12.5nm Vernier

TOPPAN is our vendor for DUV Stepper masks. Use this order form based on this quote's "product code" (do not share this quote with other vendors). Here's a PO template.

The usable ares is 22x27.4mm(X,Y) and you can not rotate the mask only the wafer. High resolution (high NA) items should be inside the 21x21 for best performance. You don't have to add all of the ASML patterns and frame, they will put the frame on. However, to get an idea here's a copy of the frame marks (Nanofab setup mask also includes these marks and barcode location, etc.). For more information reference this manual.

If you put multiple layers on one DUV plate (or if you have multiple layers across multiple mask plates), make sure that the individual layers do NOT have to be rotated in order to be aligned. The mask plates in the DUV stepper cannot be rotated, and the DUV alignment markers are not rotationally symmetric so if the wafer is rotated by 90 or 180 degrees, the alignment markers will not be detected.

Define alignment markers by etching your top Si layer (or InP). DO NOT DEFINE ALIGNMENT MARKERS BY LIFTING OFF METAL! Wafers that have used metal alignment markers (Ti/Au, liftoff) have consistently shown optical losses ~8 dB/mm (80 dB/cm). Devices fabricated using etched Si alignment markers have shown much lower losses of 8 dB/cm for a 500 nm wide, 300 nm tall waveguide with a rib etch of 200 nm. If you must use metal alignment markers talk to Geza (so he can talk some sense into you).