SOI grating definition

Current Processes

Sweeper Vertical Grating Coupler Process

   Pre-clean: Remove native oxide and/or dielectric hardmask
        HF dip
   Ebeam PR spin coat (2:1 ZEP)
       ACE,ISO,DI   
       PEII - O2 Descum (100W, 300mTorr, 60sec)   
       Dehydration Bake (150C, 5min)   
       N2 Gun (1min)    Cools and cleans wafer
       Spin 2:1 ZEP (3000rpm, 30sec) - Recipe 5    ~225nm, Use a filtered syringe
       Pre-Exposure Bake (180C, 4min)    Cover hotplate top to prevent additional particulate
   Thermal Au Evaporation       
       Evaporate 11nm Au
   Ebeam Writing Conditions       
       4th Lens   
       Dose 350uC/cm2 (Please be aware this is pitch dependent, but has shown good results over a range of pitches if the substrate is not highly doped)
   Development       
       Remove Au in wet Au etchant    10s
       DI Rinse   
       N2 Dry   
       1:1 MIBK:ISO Development - 60s    Use a fresh batch
       9:1 MIBK:ISO Rinse - 15s    DO NOT RINSE WITH DI
       N2 Dry    DO NOT RINSE WITH DI
   Grating Etch       
       AFM Calibration Recommended   
       Single Step Bosch Etch Process - JTB_GR    "Etch rate varies with temperature
       Rates:
       ~170nm/min w/o Sanovac 5
       ~141nm/min w/ Sanovac 5

Process Development Summary

Dose/Duty Cycle Analysis with Proximity Effect Observations

PPT

Future Untested Processes

Sweeper Two Etch Depth Grating Process (INCOMPLETE)

Standad EBL Spin,Bake, Exposure, Develop

   Spin AZ4210 (4000rpm, 30sec)
   Pre-Exposure Bake (95C, 1min)
  

Lithography 30 GCA Stepper / Autostepper

   Exposure: 3sec / 1sec (NEEDS CALIBRATION)
   Focus Offset: 0 (NEEDS CALIBRATION)
   NO POST-EXPOSURE BAKE
   Develop (AZ400K 1:4 diluted, 1min)
   DI Rinse

Partial deep grating etch

4210 strip in ISO

Shallow grating etch/Complete deep grating etch.

ZEP Strip (1165)