SOI grating definition
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Revision as of 22:05, 23 January 2014 by 128.111.239.162 (Talk)
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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.
