Specific Process Knowledge/Lithography/CSAR

Simple e-beam pattern in this resist has been tested, the results showed on this page. If you have questions to the process or wish to use this e-beam resist, please contact lithography at DTU Danchip.

Spin Curves

The thickness is measured on VASE Ellipsometer using a simple Cauchy model for a transparent polymer on Si. The measurements are performed at one incidence angle (70 degrees) only. 9 points on each 4" wafer has been measured; the standard deviation thus representing the homogeinity of the film on the 4" wafers.

Please be aware that I have experienced a somewhat large thickness deviation (5-8 %) depending on the amount of resist applied to the wafer before spin coating.

AllResist AR-P 6200.09 (> 2ml per 4" wafer) spinning on Spin Coater: Manual LabSpin A-5, TIGRE, 09-04-2014. Softbake 5 min @ 150 degC.
Spin Speed [rpm]	Acceleration [1/s2]	Thickness [nm]
2000	4000	226
3000	4000	194
4000	4000	170
5000	4000	151
6000	4000	142
7000	4000	127

AllResist CSAR 6200.09 1:1 in anisole (< 2ml per 4" wafer), Spin Coater: Manual LabSpin A-5, TIGRE, 16-06-2014. Softbake 2 min @ 150 degC.
Spin Speed [rpm]	Acceleration [1/s2]	Thickness [nm]
2000	4000	84
3000	4000	67
4000	4000	59
5000	4000	53
6000	4000	49

AllResist CSAR 6200.18 (< 2ml per 4" wafer), Spin Coater: Manual Standard Resists, E-5, TIGRE, 15-06-2016. Softbake 2 min @ 180 degC.
Spin Speed [rpm]	Acceleration [1/s2]	Thickness [nm]
2000	2000	1003
3000	2000	809
4000	2000	721
5000	2000	639
6000	2000	586
7000	2000	549

Contrast Curves

CSAR 6200.09

100 nm lines in both ~70 nm and ~188 nm thick CSAR has been developed with AR-600-546 (standard CSAR developer) at room temperature.

CSAR Contrast Curve, Processed by TIGRE, FEB-MARCH 2016
Resist	Spin Coat	E-beam exposure	Development	Characterisation
CSAR AR-P6200.09 AllResist, CSAR AR-P6200.09 diluted 1:1 in Anisole	08-02-2016, LabSpin E-5, 4000 rpm, 60s, softbaked 60s @ 205 degC	09-02-2016, JBX9500 E-2, 2nA aperture 5, doses 40-600 µC/cm2, 100 nm lines and 300 nm spaces	11-02-2016, Fumehood D-2, AR-600-546, rinsed in IPA 60s.	02-03-2016 AFM Icon, F-2, ScanAsyst in Air

CSAR 6200.18

100 nm lines in ~900 nm thick CSAR has been developed with AR-600-546 (standard CSAR developer) at room temperature.

CSAR Contrast Curve, Processed by TIGRE, JUNE 2016
Resist	Spin Coat	E-beam exposure	Development	Characterisation
CSAR AR-P6200.18 AllResist	15-06-2016, LabSpin E-5, 2000 rpm, 60s, softbaked 60s @ 205 degC	15-06-2016, JBX9500 E-2, 2nA aperture 5, doses 40-600 µC/cm2, 100 nm lines and 300 nm spaces	16-06-2016, Fumehood E-4, AR-600-546, 30s/60s/90s, rinsed in IPA 60s.	JUNE/JULY 2016 SEM Supra 2, 10 keV

Dark Erosion

Dark erosion has been measured on a un-exposed 4" wafer spin coated with CSAR 6200.18 to a thickness of approximately 549 nm. The resist thickness has been measured by VASE Ellipsometer before development, and after 3 minutes, 13 minutes, and 30 minutes of development in AR 600 546.

The graphs shows the measured thicknesses; the errorbars represents the standard deviations from the ellipsometric measurements. The average etch rate of CSAR is ~0.1 nm/min.

Dosetests

So far (September 2014) three wafers with CSAR have been e-beam exposed with dosetests and inspected in SEM. Thickness of resist, e-beam dose and development time has been changed somewhat from wafer to wafer:

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Process	Equipment	Parameters
		6.13	4.09	3.05
Resist	Fumehood D-3	Resist: AR-P 6200/2 diluted 1:1 in anisole (Bottled opened 16-06-2014 TIGRE)	Resist: AR-P 6200/2 diluted 1:1 in anisole (Bottled opened 16-06-2014 TIGRE)	Resist: AR-P 6200/2
Spin Coat	Spin Coater LabSpin A-5	Spin: 1 min @ 6000 rpm, softbake: 1 min @ 150 degC, thickness: ~50nm (27-08-2014 TIGRE)	Spin: 1 min @ 5000 rpm, softbake: 2 min @ 150 degC, thickness: ~53nm (16-06-2014 TIGRE)	Spin: 1 min @ 6000 rpm, softbake: 5 min @ 150 degC, thickness: ~143nm (09-04-2014 TIGRE)
E-beam exposure	JEOL 9500 E-2	Condition file: 0.2nA_ap5, doses: 180-420 muC/cm2, Shot pitch: 7-27 nm, PEC: no (27-08-2014 TIGRE)	Condition file: 0.2nA_ap5, doses: 207-242 muC/cm2, Shot pitch: 5 nm, PEC: no (02-07-2014 TIGRE)	Condition file: 2nA_ap5, doses: 207-242 muC/cm2, Shot pitch: 5 nm, PEC: no (10-04-2014 TIGRE)
Develop	Fumehood D-3	Developer: SX-AR 600-54/6, time: 30 sec, Rinse: 30 sec in IPA (28-08-2014 TIGRE)	Developer: SX-AR 600-54/6, time: 60 sec, Rinse: 30 sec in IPA (08-07-2014 TIGRE)	Developer: SX-AR 600-54/6, time: 60 sec, Rinse: 60 sec in IPA (April/May-2014 TIGRE)
Sputter Coat (please contact Ramona Valentina Mateiu for information )	Cressington 208HR, DTU CEN	3-5 nm Pt, sputtering, (29-08-2014 TIGRE)	3-5 nm Pt, sputtering (09-07-2014 TIGRE)	3-5 nm Pt, sputtering (22-05-2014 TIGRE)
Characterization	Zeiss SEM Supra 60VP, D-3	Acc voltage: 3 kV, WD: < 4mm, conducting tape close to pattern (29-08-2014 TIGRE)	Acc voltage: 3 kV, WD: < 4mm, conducting tape close to pattern (09-07-2014 TIGRE)	Acc voltage: 2 kV, WD: < 4mm, conducting tape close to pattern (06-06-2014 TIGRE)

SEM inspection

	SEM inspection of wafer 6.13, 100 nm exposed pattern, shot pitch 7 nm
300 [muC/cm2]							ACHK NOT READY

	SEM inspection of wafer 6.13, 50 nm exposed pattern, shot pitch 7 nm
270 [muC/cm2]						ACHK NOT READY
300 [muC/cm2]						ACHK NOT READY

	SEM inspection of wafer 6.13, 30 nm exposed pattern, shot pitch 7 nm
270 [muC/cm2]					ACHK NOT READY
300 [muC/cm2]					ACHK NOT READY

	SEM inspection of wafer 6.13, 20 nm exposed pattern, shot pitch 7 nm
270 [muC/cm2]			ACHK NOT READY
300 [muC/cm2]			ACHK NOT READY

	SEM inspection of wafer 4.09, 50 nm exposed pattern, shot pitch 5 nm
230 [muC/cm2]

	SEM inspection of wafer 4.09, 30 nm exposed pattern, shot pitch 5 nm
219 [muC/cm2]
230 [muC/cm2]
242 [muC/cm2]

	SEM inspection of wafer 4.09, 20 nm exposed pattern, shot pitch 5 nm
242 [muC/cm2]
253 [muC/cm2]

	SEM inspection of wafer 3.05, 50 nm exposed pattern, shot pitch 5 nm
219 [muC/cm2]
230 [muC/cm2]
242 [muC/cm2]

	SEM inspection of wafer 3.05, 30 nm exposed pattern, shot pitch 5 nm
219 [muC/cm2]
230 [muC/cm2]
242 [muC/cm2]

	SEM inspection of wafer 3.05, 20 nm exposed pattern, shot pitch 5 nm
230 [muC/cm2]
242 [muC/cm2]
253 [muC/cm2]

Etch Tests

If you have wafers or chips with CSAR you would like to have tested, please send me an [email].

Chlorine versus flourine-based etches

We have experienced problems with removal of CSAR after chlorine-based dry etch, see the file File:DryEtchTestsCSAR.pdf. It seems the chlorine etch forms particles of chlorinated CSAR on the surface, and these particles remains on the surface after resist removal with AR-600-71. The C4F8/SF6 etch also forms particles on the surface, but much smaller than those formed in the chlorine etch. It seems these particles are removed after 3 minutes in AR-600-71.

How to mount chips in dry etch tools

All etch rates presented here are measured on chips (i.e. diced 4" wafers) crystal bonded to a carrier. The carrier is either a blank Si wafer, a Si wafer spin coated with resist or a Si wafer coated with ALD grown Al2O3.

Etch Tests of CSAR, recipe 'nano1.42', DRIE PEGASUS, A-1. CSAR thickness measured on Ellipsometer VASE at 70 degrees

Sample	CSAR Etch rate nm/min
Full 4" Si wafer with non-patterned ~180 nm CSAR	~56.5 (based on 2 runs)
Full 4" Si wafer with non-patterned ~240 nm CSAR, postbaked 60 sec @ 130 degC	~56.5 (based on 2 runs)
1/4 4" Si wafer with non-patterned ~125 nm CSAR, not crystal bonded to Si carrier	~83.3 (based on 3 runs)
1/4 4" Si wafer with non-patterned ~125 CSAR, crystal bonded to 4" Si carrier	~54 (based on 1 run)

Etch rates and profile inspection

Continous Etches

Recipe nano1.42 on Deep Reactive Ion Etch PEGASUS A-1

Recipe	Gasses	C4F8 75 sccm, SF6 38 sccm	Profiles of lines exposed at 300 µC/cm2, etched 2:30 minutes (150s) with recipe 'nano1.42'
	Pressure	4 mTorr, Strike: 3 secs @ 15 mTorr
	Power	800 W Coil Power, 40 W Platen Power
	Platen temperature	- 20°C
Conditions	Conditioning	Pre-clean: 10 min oxygen clean 5 min oxygen clean between runs
Etch rates	Si	500 nm lines: ~200 nm/min 190 nm lines: ~200 nm/min 102 nm lines: ~190 nm/min 61 nm lines: ~170 nm/min
	CSAR	~55 nm/min

Recipe processC on Deep Reactive Ion Etch PEGASUS A-1

Recipe	Gasses	C4F8 70 sccm, SF6 38 sccm	Profiles of lines exposed at 300 µC/cm2, etched 60s with recipe 'ProcessC'
	Pressure	4 mTorr, Strike: secs @ mTorr
	Power	450 W Coil Power, 100 W Platen Power
	Platen temperature	10°C
Conditions	Conditioning	Pre-clean: 10 min oxygen clean 5 min oxygen clean between runs
Etch rates	Si	500 nm lines: ~300 nm/min 102 nm lines: ~250 nm/min
	CSAR	158 nm/min

Bosch Etch

Recipe NBoost01 on Deep Reactive Ion Etch PEGASUS A-1

Recipe	Deposition step	Duration	2.5 s	Profiles of lines exposed at 300 µC/cm2, etched 6:00 minutes with recipe 'NBoost01'
		Gasses	C4F8 50 sccm, SF6 0 sccm
		Pressure	10 mTorr
		Powers	500 W Coil
	Etch step (boost)	Duration	1.5 s
		Gasses	C4F8 0 sccm, SF6 60 sccm
		Pressure	5 mTorr
		Powers	400 W Coil, 50 W Platen
	Etch step (main)	Duration	3.5 s
		Gasses	C4F8 40 sccm, SF6 60 sccm
		Pressure	15 mTorr
		Powers	400 W Coil, 20 W Platen
	Platen temperature	20 °C
Conditions	Conditioning	Pre-clean: 10 min oxygen clean 5 min oxygen clean between runs
Etch rates	Si	200 nm lines: ~700 nm/min 130 nm lines: ~580 nm/min
	CSAR	~18 nm/min