SOI grating definition
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Contents
Past Processes[edit]
Sweeper Vertical Grating Coupler Process - (ZEP:Anisol(2:1) Soft mask, limited to shallow ~150-200nm Si gratings, used in SWEEPER for gratings <100nm)[edit]
NOTE: YOUR CHIP MUST FIT INTO AN EBL HOLDER. PLEASE CONSULT THE EBL HANDBOOK FOR HOLDER SIZES. SOME CHIP SIZES DON'T FIT IN ANY HOLDER!
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-520A:Anisol("A Thinner") (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 ALTERNATE to Au: Conductive Polymer (This is recommended if you have Si electrical processing or regrowth after this module) Spin on Conductive Polymer (Aquasave) (3000rpm, 30sec) Pre-Exposure Bake (90C, 1min) Cover hotplate top to prevent additional particulate 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 (If thermal Au is used) Remove Au in wet Au etchant 10s DI Rinse 1min (required to rinse Au etchant AND remove conductive polymer) N2 Dry (be gentle on the gratings) 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 etch depth calibration recommended 30min chamber clean in manual mode with cleaning wafer - 30mT, O2/Ar flow-rate=20/10sccm, bias/ICP powers=0/825W (especially after a prior users long Bosch etch) Single Step Bosch Etch Process - BOV_J_01 (19mT, 18/850W, C4F8/Ar/Ar flow-rate=56/24/20sccm) Rough Rates: ~170nm/min w/o Sanovac 5 ~141nm/min w/ Sanovac 5 Strip ZEP (2:1) 1165 Soak at 80C - 10min PEII - O2 Descum (100W, 300mTorr, 60-120sec)
Sweeper DBR Grating Process - (100% ZEP Soft mask, Designed for deeper Si Gratings ~200-700nm, used in SWEEPER for SGDBR gratings ~275nm)[edit]
NOTE: YOUR CHIP MUST FIT INTO AN EBL HOLDER. PLEASE CONSULT THE EBL HANDBOOK FOR HOLDER SIZES. SOME CHIP SIZES DON'T FIT IN ANY HOLDER!
Pre-clean: Remove native oxide and/or dielectric hardmask HF dip Ebeam PR spin coat (%100 ZEP) ACE,ISO,DI PEII - O2 Descum (100W, 300mTorr, 60sec) Dehydration Bake (150C, 5min) N2 Gun (1min) Cools and cleans wafer Spin 100% ZEP-520A (2000rpm, 40sec) - Recipe 3 Use a filtered syringe Pre-Exposure Bake (180C, 4min) Cover hotplate top to prevent additional particulate Thermal Au Evaporation Evaporate 11nm Au ALTERNATE to Au: Conductive Polymer (This is recommended if you have Si electrical processing or regrowth after this module) Spin on Conductive Polymer (Aquasave) (3000rpm, 30sec) Pre-Exposure Bake (90C, 1min) Cover hotplate top to prevent additional particulate Ebeam Writing Conditions 4th Lens Dose 500uC/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 (If thermal Au is used) Remove Au in wet Au etchant 10s DI Rinse 1min (required to rinse Au etchant AND remove conductive polymer) N2 Dry (be gentle on the gratings) 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 etch depth calibration recommended 30min chamber clean in manual mode with cleaning wafer - 30mT, O2/Ar flow-rate=20/10sccm, bias/ICP powers=0/825W (especially after a prior users long Bosch etch) Single Step Bosch Etch Process - BOV_J_01 (19mT, 18/850W, C4F8/Ar/Ar flow-rate=56/24/20sccm) Rough Rates: ~170nm/min w/o Sanovac 5 ~141nm/min w/ Sanovac 5 Strip ZEP (2:1) 1165 Soak at 80C - 10min PEII - O2 Descum (100W, 300mTorr, 60-120sec)
Standard Hybrid Si Process[edit]
link to .xls
Process Development Summary[edit]
Dose/Duty Cycle Analysis with Proximity Effect Observations[edit]
media:2010-03-01_Grating_Update.pptx
media:2010-12-07_Grating_Update.pptx
media:2012-05-04_-_Deep_Grating_Etch_Process_shortloop_JTB.pptx
Alternate Processes[edit]
Sweeper One Pattern, Two Etch Depth Grating Process with ZEP(2:1)/Oxide/Cr/Oxide Mask[edit]
(Long process whose only benefit seems to be that one can Dektak or AFM the patterns while the Cr mask is still on and re-etch if necessary given the near infinite selectivity of Cr to the Si etch)
Oxide Hardmask Deposition - PlasmaTherm PECVD 50+50nm SiO2 Add Si watch sample VASE Si Watch Sample - Note Oxide Height Cr Deposition - Ebeam #1 100nm - This is a value that has been calibrated, but there would be value in using 25nm to decrease the undercut Add a watch sample with orange vacuum tape in the middle Dektak the watch sample after removing tape Oxide Hardmask Deposition - PlasmaTherm PECVD 50nm SiO2 Add Si watch sample VASE Si Watch Sample - Note Oxide Height Ebeam Resist spin coat (2:1 ZEP) ACE,ISO,DI PEII - O2 Descum (100W, 300mTorr, 30sec) Dehydration Bake (150C, 5min) N2 Gun (1min) Cools and cleans wafer HMDS 5000rpm 30s - Let sit on chip for 30s before spinning Spin 2:1 ZEP:Anisol (3000 rpm, 30sec) - Recipe 5 ~225nm, Use a filtered syringe Pre-Exposure Bake (180C, 4min) Cover hotplate top to prevent additional particulate Conductive polymer spin coat Aquasave (3000 rpm, 30sec) - Recipe 5 Pre-Exposure bake (90C, 30sec) Ebeam Writing Conditions 4th Lens - 2nA Dose 500uC/cm2 (Please be aware this is pitch dependent, but has shown good results over a range of pitches with a ~45nm undercut in the 100nm of Cr) EBL Development DI Rinse - 60s Removes Aquasave N2 Dry - Be gentle the resist can move under high pressure 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 - Be gentle the resist can move under high pressure Microscope Inspection - AFM Pattern Acknowledgement - Hardmask Etch - ICP#2 O2 Clean - 10min 2min season - ICP#2 recipe #104 - CF4/CHF3/02 - 5/35/10sccm - 500Wicp, 50Wccp, 0.5Pa Oxide Nano Etch - ~80nm/min - over etch 25% (50s for 50nm) ICP#2 recipe #104 - CF4/CHF3/02 - 5/35/10sccm - 500Wicp, 50Wccp, 0.5Pa Strip ZEP:Anisol (2:1) 1165 Soak at 80C - 10min PEII - O2 Descum (100W, 300mTorr, 60sec) AFM Pattern Acknowledgement - Save grating cross-sections confirm height with oxide thickness measured earlier Cr Etch - ~35nm/min - over etch 25% (3m45s for 100nm) ICP#2 recipe #145 - Cl2/02 - ?/?sccm - ?Wicp, ?Wccp, ?Pa AFM Pattern Acknowledgement - Save grating cross-sections confirm height with Cr and top oxide thickness measured earlier Oxide Nano Etch - ~80nm/min - over etch 25% (100s for 100nm) ICP#2 recipe #104 - CF4/CHF3/02 - 5/35/10sccm - 500Wicp, 50Wccp, 0.5Pa AFM Pattern Acknowledgement - Save grating cross-sections confirm height with Cr and lower oxide thickness measured earlier top oxide should be gone. Grating Shallow Etch - Si Deep RIE Etcher (50nm) Chamber Prep (no sample): O2 Clean - 30min - Click standby, then enter manual mode. (the electrode temp must be with in bounds to enter standby mode) Load Clean wafer. Parameters 10C,30mTorr,He=10,Ar=10,O2=30,Power RF2=800 2min season - BOV_J_01 - C4F8/SF6/Ar = 56/24/20sccm @ ICP/CCP = 850/18W Single step Bosch etch process - BOV_J_01 - C4F8/SF6/Ar = 56/24/20sccm @ ICP/CCP = 850/18W Rates: ZEP ~ 35-40nm/min, ~63-141nm/min w/ Sanovac 5 AFM Pattern Acknowledgement - Save grating cross-sections Cr mask will show a negligible etch so the Si depth should be clear. Add GRAT1 layer (Protects Sweeper gratings) Spin AZ4210 (4000rpm, 30sec) Pre-Exposure Bake (95C, 1min) Lithography - Pattern a window in the deep etch region Litho Tool: GCA Stepper / Autostepper Exposure: 3sec / 1sec Focus Offset: 0 NO POST-EXPOSURE BAKE Develop (AZ400K 1:4 diluted, 2min(way over-developed) DI Rinse PEII - O2 Descum (100W, 300mTorr, 30sec) - Do not repeat this because this oxidizes the Cr and will enlarge the grating pattern Microscope Inspection - Grating Finish Deep Etch - Etch the difference in depths (deep target (275nm) - shallow target (50nm) = 225nm) AFM etch depth calibration recommended Chamber Prep (no sample): O2 Clean - 30min - Click standby, then enter manual mode. (the electrode temp must be with in bounds to enter standby mode) Load Clean wafer. Parameters 10C,30mTorr,He=10,Ar=10,O2=30,Power RF2=800 2min season - BOV_J_01 - C4F8/SF6/Ar = 56/24/20sccm @ ICP/CCP = 850/18W Single step Bosch etch process - BOV_J_01 - C4F8/SF6/Ar = 56/24/20sccm @ ICP/CCP = 850/18W Rates: ZEP ~ 35-40nm/min, Si ~170nm/min w/o Sanovac 5, ~63-141nm/min w/ Sanovac 5 Strip PR 1165 Soak at 80C - 10min PEII - O2 Descum (100W, 300mTorr, 60-120sec) AFM Pattern Acknowledgement - Save grating cross-sections from AFM test structure shallow and deep Cr Etch - ~35nm/min - over etch 25% (3m45s for 100nm) ICP#2 recipe #145 - Cl2/02 - ?/?sccm - ?Wicp, ?Wccp, ?Pa AFM Pattern Acknowledgement - Save grating cross-sections from AFM test structure shallow and deep BHF Dip AFM Pattern Acknowledgement - Save grating cross-sections from AFM test structure shallow and deep SEM - Save top down SEMs for different locations and different grating types.