Difference between revisions of "SOI grating definition"

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(→‎Sweeper Two Etch Depth Grating Process (UNTESTED))
(→‎Sweeper DBR Grating Process - (100% ZEP Soft mask, Designed for deeper Si Gratings ~200-700nm, used in SWEEPER for SGDBR gratings ~275nm))
 
(30 intermediate revisions by 7 users not shown)
Line 1: Line 1:
 
Back to [[Process_Hybrid_Silicon]].
 
Back to [[Process_Hybrid_Silicon]].
 
==Past Processes==
 
==Past Processes==
−
===Sweeper Vertical Grating Coupler Process===  
+
===Sweeper Vertical Grating Coupler Process - (ZEP:Anisol(2:1) Soft mask, limited to shallow ~150-200nm Si gratings, used in SWEEPER for gratings <100nm)===  
 +
 
 +
    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
 
     Pre-clean: Remove native oxide and/or dielectric hardmask
 
         HF dip
 
         HF dip
Line 9: Line 13:
 
         Dehydration Bake (150C, 5min)   
 
         Dehydration Bake (150C, 5min)   
 
         N2 Gun (1min)    Cools and cleans wafer
 
         N2 Gun (1min)    Cools and cleans wafer
−
         Spin 2:1 ZEP (3000rpm, 30sec) - Recipe 5    ~225nm, Use a filtered syringe
+
         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
 
         Pre-Exposure Bake (180C, 4min)    Cover hotplate top to prevent additional particulate
 
     Thermal Au Evaporation       
 
     Thermal Au Evaporation       
 
         Evaporate 11nm Au
 
         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       
 
     Ebeam Writing Conditions       
 
         4th Lens   
 
         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)
 
         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      
+
     Development
−
         Remove Au in wet Au etchant    10s
+
         (If thermal Au is used) Remove Au in wet Au etchant    10s
−
         DI Rinse  
+
         DI Rinse 1min (required to rinse Au etchant AND remove conductive polymer)
−
         N2 Dry  
+
         N2 Dry (be gentle on the gratings)
 
         1:1 MIBK:ISO Development - 60s    Use a fresh batch
 
         1:1 MIBK:ISO Development - 60s    Use a fresh batch
 
         9:1 MIBK:ISO Rinse - 15s    DO NOT RINSE WITH DI
 
         9:1 MIBK:ISO Rinse - 15s    DO NOT RINSE WITH DI
Line 25: Line 32:
 
     Grating Etch       
 
     Grating Etch       
 
         AFM etch depth calibration recommended   
 
         AFM etch depth calibration recommended   
−
         Single Step Bosch Etch Process - JTB_GR
+
        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)
−
         Rates:
+
         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
 
         ~170nm/min w/o Sanovac 5
 
         ~141nm/min w/ Sanovac 5
 
         ~141nm/min w/ Sanovac 5
 
     Strip ZEP (2:1)
 
     Strip ZEP (2:1)
 
         1165 Soak at 80C - 10min
 
         1165 Soak at 80C - 10min
−
         PEII - O2 Descum (100W, 300mTorr, 60sec)
+
        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)===
 +
 
 +
    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==
 
==Standard Hybrid Si Process==
Line 37: Line 85:
 
==Process Development Summary==
 
==Process Development Summary==
 
===Dose/Duty Cycle Analysis with Proximity Effect Observations===
 
===Dose/Duty Cycle Analysis with Proximity Effect Observations===
−
[[file:2010-03-01_Grating_Update.pptx]]
+
[[media:2010-03-01_Grating_Update.pptx]]
  
−
[[file:2010-12-07_Grating_Update.pptx]]
+
[[media:2010-12-07_Grating_Update.pptx]]
  
−
==Future Untested Processes==
+
[[media:2012-05-04_-_Deep_Grating_Etch_Process_shortloop_JTB.pptx]]
−
===Sweeper Two Etch Depth Grating Process (UNTESTED)===
+
 
−
     Oxide Hardmask Deposition - Advanced Vacuum PECVD  
+
==Alternate Processes==
−
         44nm Oxide
+
===Sweeper One Pattern, Two Etch Depth Grating Process with ZEP(2:1)/Oxide/Cr/Oxide Mask===
−
     Ebeam PR spin coat (2:1 ZEP)
+
(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   
 
         ACE,ISO,DI   
 
         PEII - O2 Descum (100W, 300mTorr, 30sec)   
 
         PEII - O2 Descum (100W, 300mTorr, 30sec)   
 
         Dehydration Bake (150C, 5min)   
 
         Dehydration Bake (150C, 5min)   
 
         N2 Gun (1min)    Cools and cleans wafer
 
         N2 Gun (1min)    Cools and cleans wafer
−
         HMDS 5000rpm 30s
+
         HMDS 5000rpm 30s - Let sit on chip for 30s before spinning
−
         Spin 2:1 ZEP (3000rpm, 30sec) - Recipe 5    ~225nm, Use a filtered syringe
+
         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
 
         Pre-Exposure Bake (180C, 4min)    Cover hotplate top to prevent additional particulate
 
     Conductive polymer spin coat
 
     Conductive polymer spin coat
Line 57: Line 118:
 
         Pre-Exposure bake (90C, 30sec)
 
         Pre-Exposure bake (90C, 30sec)
 
     Ebeam Writing Conditions       
 
     Ebeam Writing Conditions       
−
         4th Lens  
+
         4th Lens - 2nA 
−
         Dose 400uC/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)
+
         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)
−
     Development       
+
     EBL Development       
 
         DI Rinse - 60s Removes Aquasave   
 
         DI Rinse - 60s Removes Aquasave   
−
         N2 Dry  
+
         N2 Dry - Be gentle the resist can move under high pressure
 
         1:1 MIBK:ISO Development - 60s    Use a fresh batch
 
         1:1 MIBK:ISO Development - 60s    Use a fresh batch
 
         9:1 MIBK:ISO Rinse - 15s    DO NOT RINSE WITH DI
 
         9:1 MIBK:ISO Rinse - 15s    DO NOT RINSE WITH DI
−
         N2 Dry    DO NOT RINSE WITH DI
+
         N2 Dry    DO NOT RINSE WITH DI - Be gentle the resist can move under high pressure
−
     AFM Pattern Acknowledgement - Save grating cross-sections for sweeper and DBR types 
+
    Microscope Inspection -
 +
     AFM Pattern Acknowledgement -
 
     Hardmask Etch - ICP#2
 
     Hardmask Etch - ICP#2
 
         O2 Clean - 10min
 
         O2 Clean - 10min
−
         2min season ''(CHEMS AND FLOWS NEEDED)''
+
         2min season - ICP#2 recipe #104 - CF4/CHF3/02 - 5/35/10sccm  - 500Wicp, 50Wccp, 0.5Pa
−
         Oxide Nano Etch - 110nm/min ''(CHEMS AND FLOWS NEEDED)''
+
        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)         
 
     Grating Shallow Etch - Si Deep RIE Etcher (50nm)         
−
         O2 Clean - 30min
+
         Chamber Prep (no sample):
−
        2min season ''(CHEMS AND FLOWS NEEDED)''
+
          O2 Clean - 30min - Click standby, then enter manual mode.
−
         Single step Bosch etch process - BOV_J_01 ''(CHEMS AND FLOWS NEEDED)''
+
            (the electrode temp must be with in bounds to enter standby mode)
−
        Rates: ~170nm/min w/o Sanovac 5, ~141nm/min w/ Sanovac 5
+
            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)
 
     Add GRAT1 layer (Protects Sweeper gratings)
 
         Spin AZ4210 (4000rpm, 30sec)
 
         Spin AZ4210 (4000rpm, 30sec)
Line 83: Line 160:
 
             Focus Offset: 0
 
             Focus Offset: 0
 
             NO POST-EXPOSURE BAKE
 
             NO POST-EXPOSURE BAKE
−
             Develop (AZ400K 1:4 diluted, 2min)
+
             Develop (AZ400K 1:4 diluted, 2min(way over-developed)
 
             DI Rinse
 
             DI Rinse
−
    AFM Pattern Acknowledgement - Save grating cross-sections for sweeper and DBR types HOLD IF BOTTOMS ARE DIRTY 
+
        PEII - O2 Descum (100W, 300mTorr, 30sec) - Do not repeat this because this oxidizes the Cr and will enlarge the grating pattern
−
     Grating Finish Deep Etch - Etch the difference in depths (deep target - shallow target)       
+
    Microscope Inspection -
−
            AFM etch depth calibration recommended   
+
     Grating Finish Deep Etch - Etch the difference in depths (deep target (275nm) - shallow target (50nm) = 225nm)       
−
            O2 Clean - 30min
+
        AFM etch depth calibration recommended   
−
             2min season ''(CHEMS AND FLOWS NEEDED)''
+
        Chamber Prep (no sample):
−
            Single step Bosch etch process - JTB_GR
+
          O2 Clean - 30min - Click standby, then enter manual mode.
−
             Rates: ~170nm/min w/o Sanovac 5, ~141nm/min w/ Sanovac 5
+
             (the electrode temp must be with in bounds to enter standby mode)
−
    AFM Pattern Acknowledgement - Save grating cross-sections for sweeper and DBR types 
+
            Load Clean wafer. Parameters 10C,30mTorr,He=10,Ar=10,O2=30,Power RF2=800
−
     Strip PR & ZEP (2:1)
+
          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
 
         1165 Soak at 80C - 10min
−
         PEII - O2 Descum (100W, 300mTorr, 60sec)
+
         PEII - O2 Descum (100W, 300mTorr, 60-120sec)
−
     AFM Pattern Acknowledgement - Save grating cross-sections for sweeper and DBR types  
+
     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.
 
     SEM - Save top down SEMs for different locations and different grating types.

Latest revision as of 22:05, 23 January 2014

Back to Process_Hybrid_Silicon.

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.
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