siepicfab-ebeam-zep 0.1.6

SiEPICfab_EBeam_ZEP_PDK: process design kit (PDK) for fabrication using electron beam lithography, and a library silicon photonics components.

SiEPICfab-EBeam-ZEP-PDK

SiEPIC Program EBeam PDK for the ZEP process

Technical summary:

• SOI wafer, 220 nm silicon
• Baseline process:
  • Single full etch, using a positive resist (ZEP)
  • No cladding
• Optional process modules:
  • Shuksan laser integration (deep trench, laser attach, photonic wire bonds)
  • Metals
  • Oxide release etch for NEMS devices
• ZEP 520A - 550 nm thick Process documentation, including process bias for Thick Zep
• Zep 520A-7 -300 nm thick State of the Art Component Information

Wafer details:

• 200mm
• Top Silicon:
  • CZ grown P type Boron doped
  • 30-60 ohm cm. (approx 5e14 cm^-3, see https://www.pvlighthouse.com.au/resistivity)
  • 110 orientation
  • Notched within 1 degree
  • 220 nm thick+-12.5nm, all measured points, 5mm edge exclusion
• BOX:
  • 3500 nm+-150nm all points, 5mm edge exclusion
• Handle:
  • CZ, P type Boron doped
  • 500-1000 ohm cm
  • 100 orientation
  • 725 um thick +-15 um
  • Backside etched with oxide
  • Max 50 um warp

Layer table

Name	Layer/datatype	Description
Si_core	1/0	Layer to draw silicon waveguides; will be XORed with Si_clad.
Si_clad	1/2	Layer to draw the extent of the Si etch, including cladding and core.
Si_etch_highres	100/0	High Resolution Layer to draw fully etched trenches, but use SLS/Shape PEC. (trench)
Si_etch_highres_nobias	101/0	High Resolution Layer with no bias: Small features are resolved true to GDS sizing
M1	11/0	Layer to draw metal routing, heaters, etc
DeepTrench	201/0	Layer to define deep trench etch regions. For edge couplers
Floorplan	99/0	Marks the layout design area.
text	10/0	Text labels for automated measurements.
DevRec	68/0	Device recognition layer for DRC.
PinRec	1/10	Port/pins recognition layer for snapping and connectivity checks.
Waveguide	1/99	Virtual layer, guiding shape for waveguide, used for length calculation
SEM	200/0	Requests for SEM images. Rectangles in a 4:3 aspect.
EBL-Regions	8100/0	EBL Litho Manual Write Field Regions
NbTiN	12/0	Superconducting Niobium Titanium Nitride
TiAu	13/0	Titanium Gold for NbTiN (Check with the fabricator if you should use TiAu or M1)

EBL Write Field Regions

• layer “EBL-Regions”: Designer draws a rectangle to designate a write field. Maximum size of 1x1 mm. Everything inside is written in one EBL field.
• Designer chooses their own fields to avoid field stitching boundaries, or to choose where the boundaries are placed
• Can have adjacent fields touching. Exported in order so that they are written as a group, which reduces stitching errors due to machine drift
• Run DRC check to make sure the EBL regions are defined correctly
• SiEPIC > "Export EBL Write Field Regions" - Script that exports EBL regions. Beamer will import and use for manual field placement.

People

UBC FAB Team

• Davin Birdie
• Matthias Kroug
• Matthew Mitchell
• Sheri Jahan Chowdhury

UBC Designers

• Ben Cohen (polymer modulators, biosensor)
• Iman Taghavi (polymer modulators)
• Mohammed Al-Qadasi (biosensor)
• Mustafa Hammood (PCM)
• Sheri Jahan Chowdhury (laser integration to biosensor)
• Wangning Cai (inverse design)
• Mateo Branion-Calles (Quantum Integration)

Run schedule

• SiEPICfab process development runs, typically monthly
• Contact Serge Khorev for scheduling

PDK installation instructions:

Software - KLayout, SiEPIC-Tools

• Install KLayout version 0.27 or greater (latest version): http://www.klayout.de/build.html
• Install SiEPIC-Tools versus 0.3.71 or higher (latest version), using the Package Manager (instructions)

PDK Installation via GitHub Desktop (easiest way to receive updates):

• Install GitHub Desktop, https://desktop.github.com (works on Windows, Mac, Ubuntu)

• Clone this repostory using GitHub Desktop. Do this by clicking on the green "Code" button, then "Open with GitHub Desktop"

  • Example below assumes it is installed in your Documents folder.

• There are different branches, "main" and "experimental". Choose the branch in GitHub Desktop via the "Default Branch" button

• Start KLayout:

  • Menu Tools > Manage Technologies
  • In the window on the left (Technologies), right click, then Import Technology
  • Navigate to your Documents / GitHub folder and select GitHub / SiEPICfab-EBeam-ZEP-PDK, and find the .lyt file, then OK.
  • Create a new layout, menu File > New Layout, Technology = SiEPICfab-EBeam-ZEP
    • you should see the layer table (corresponding to the table detaileda above), and the SiEPIC menu

• If that doesn't work, close KLayout, and try this:

  • Create a symbolic link from the repo PDK folder into your KLayout tech folder. If the tech folder does not exist, create it, ensuring the name of the folder is "tech".

  • On Mac:

       $ mkdir ~/.klayout/tech
       $ ln -s ~/Documents/GitHub/SiEPICfab-EBeam-ZEP-PDK/SiEPICfab_EBeam_ZEP ~/.klayout/tech
    

  • On Windows:

       $ cd C:\Users\<username>\KLayout\tech
       $ mklink /J SiEPICfab_EBeam_ZEP "C:\Users\<username>\Documents\GitHub\SiEPICfab-EBeam-ZEP-PDK\SiEPICfab_EBeam_ZEP"
    

• Start KLayout, and create a new layout choosing Technology = SiEPICfab_EBeam_ZEP

  • you should see the layer table, and the SiEPIC menu

PDK Updates:

• subscribe to commits and release updates using the "Watch" button, https://github.com/SiEPIC/SiEPICfab-EBeam-ZEP-PDK
• use GitHub Desktop to refresh the PDK ("Fetch origin"), then restart KLayout

PDK Support:

• If you encounter problems, notice errors or omissions, or have suggestions, please post them here: new Issue. You may copy and paste a screenshot into the Issue.

Waveguides:

• Draw a Path on the layer "Waveguide"
• menu SiEPIC > Waveguides > Path to Waveguides ("W"), choose one of the waveguide types

Library:

• The SiEPICfab_EBeam_ZEP library contains true geometry fixed cells including a 50/50 splitter (ebeam_bdc_te1550), y-branch (ebeam_y_1550), and terminator.
• The SiEPICfab_EBeam_ZEP library contains hidden geometry (black box) fixed cells: GC_1550_220_Blackbox; these will be replaced prior to fabrication
• The SiEPICfab_EBeam_ZEP library contains parameterized cells including Waveguide and taper

Submission

• Design Rule check: please check using both:
  • KLayout SiEPIC > Verification > Design Rule Check (DRC) - SiEPICfab-ZEP
  • KLayout SiEPIC > Verification > Functional Layout Check
  • All the design rules should be considered as "warnings", and you do not need to obtain Waivers for violations
• File format: GDS or OASIS. Use the KLayout SiEPIC > Export for SiEPICfab-ZEP fabrication
  • this script performs the required layer boolean operations and basic clean-up

For SiEPICfab members:

• Please fill in the form here: https://docs.google.com/forms/d/e/1FAIpQLSeFrlBozNWQ5TLEB5X2LdBlOMgfqfcz9K8cZBww6_-Xg-Zsag/viewform
  • choose "Process Development"
• Designs should be uploaded to the UBC Nextcloud server (links provided in the Google form)

Contributions to the PDK

• Please make contributions, preferably using a Pull request.