Specific Process Knowledge/Lithography/CSAR: Difference between revisions

Revision as of 12:13, 8 January 2015

Resist	Polarity	Manufacturer	Comments	Technical reports	Spinner	Developer	Rinse	Remover	Process flows (in docx-format)
CSAR	Positive	AllResist	Standard positive resist, very similar to ZEP520.	Allresist_CSAR62_English.pdf‎,, CSAR_62_Abstract_Allresist.pdf‎	Manual Spinner 1 (Laurell), Spin Coater Labspin	XAR-600-546, XAR-600-548, N50, MIBK:IPA	IPA	AR-600-71, 1165 Remover	Process_Flow_CSAR.docx‎

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 Tine Greibe at tigre@danchip.dtu.dk.

Process Flow

Test of Chemically Semi-Amplified Resist (CSAR); a positive e-beam resist from AllResist (AR-P 6200-2).

Equipment	Process Parameters	Comments
Pretreatment
4" Si wafers	No Pretreatment
Spin Coat
Spin Coater Manual, LabSpin, A-5	AR-P 6200/2 AllResist E-beam resist 60 sec at various spin speed. Acceleration 4000 s-2, softbake 1 - 5 min at 150 deg Celcius	Disposal pipette used; clean by N2-gun before use. Use approximately 1.5 ml per 4" wafer, never use a pipette twice. Softbake is not a crucial step, see e-mail correspondence with AllResist here.
Characterization
Ellipsometer VASE B-1	9 points measured on 100 mm wafer	ZEP program used; measured at 70 deg only
E-beam Exposure
JEOL 9500 E-beam writer, E-1	Dosepattern 15nm - 100nm, dose 120-350 muC/cm2	Virtual chip mark height detection (CHIPAL V1) used in corner of every dose array
Development
Fumehood, D-3	60 sec in X AR 600-546, 60 sec rinse in IPA, N2 Blow dry	Gentle agitation while developing. After developing, wafer is immersed in beaker with IPA, subsequently blow dried with N2 gun.
Characterization
Zeiss SEM Supra 60VP, D-3	2-3 kV, shortest working distance possible, chip mounted with Al tape	For dosepattern SEM inspection: the wafers are diced into smaller pieces and sputter coated with Pt at DTU CEN before SEM inspection; please contact Ramona Valentina Mateiu for further information.

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.

Dosepattern has been e-beam exposured and SEM inspected on those wafers marked by silver gray.

AllResist AR-P 6200 (> 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]	St Dev
2000	4000	225.98	0.97
3000	4000	194.00	0.6
4000	4000	169.57	0.32
5000	4000	151.47	0.26
6000	4000	142.38	0.41
7000	4000	126.59	0.36

AllResist CSAR (< 2ml per 4" wafer) on Spin Coater: Manual LabSpin A-5, TIGRE, 16-06-2014. Softbake 2 min @ 150 degC.
Spin Speed [rpm]	Acceleration [1/s2]	Thickness [nm]	St Dev
3000	4000	201.61	1.20
4000	4000	173.89	0.64
5000	4000	155.91	0.65

AllResist CSAR 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]	St Dev
2000	4000	83.48	0.49
3000	4000	67.12	0.41
4000	4000	58.64	0.44
5000	4000	53.13	0.39
6000	4000	48.76	0.38

Contrast Curves

100 nm lines in ~145 nm thick CSAR has been developed with AR-600-546 (standard CSAR developer) with and without agitation at room temperature and at 5 degrees Celsius. Furthermore, same pattern ahs been developed with N50 (standard developer for ZEP520A).

wafer 9.19 Contrast Curve, Processed by TIGRE, Dec-Jan 2014-2015
Resist	Spin Coat	E-beam exposure	Development	Characterisation
CSAR AR-P6200 AllResist	19-12-2014, LabSpin A-1, 4000 rpm, 60s, softbaked 60s @ 150degC	19-12-2014, JBX9500 E-2, 2nA aperture 5, doses 60-600 µC/cm2, 100 nm lines with 300 nm spaces	22-12-2014, 05-01-2015, Fumehood D-2, misc developers, rinsed in IPA 60s. The cold development was performed with developer stored in refrigerator (Cx1), exact temperature was not measured.	23-12-2014, 05-01-2015, Zeiss Supra 60VP, 10kV, Inlens detector, stage at - 4-5 degrees. Samples not coated before inspection.

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:

Process	Equipment	Parameters
Process	Equipment	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	Cressington 208HR, DTU CEN, please contact Ramona Valentina Mateiu for information	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 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
240 [muC/cm2]					ACHK NOT READY
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
230 [muC/cm2]
242 [muC/cm2]
253 [muC/cm2]

SEM inspection of wafer 4.09, 15 nm exposed pattern, shot pitch 5 nm
253 [muC/cm2]
276 [muC/cm2]

SEM inspection of wafer 3.05, 50 nm exposed pattern, shot pitch 5 nm
207 [muC/cm2]			NO ACHK READY
219 [muC/cm2]
230 [muC/cm2]
242 [muC/cm2]

SEM inspection of wafer 3.05, 30 nm exposed pattern, shot pitch 5 nm
207 [muC/cm2]			NO ACHK READY
219 [muC/cm2]
230 [muC/cm2]
242 [muC/cm2]

SEM inspection of wafer 3.05, 20 nm exposed pattern, shot pitch 5 nm
207 [muC/cm2]			NO ACHK READY
230 [muC/cm2]
242 [muC/cm2]
253 [muC/cm2]

Etch Tests

The tests presented here are prelimenary results and this page will be updated regularly. I post this as the interest in etch resistance of CSAR is increasing; if you have wafers or chips 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**
Sample	Etch rate nm/min
Sample	CSAR (Ellipsometer)
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
Etch rates	CSAR	~55 nm/min

**Recipe processC on Deep Reactive Ion Etch PEGASUS A-1**
Recipe	Gasses	C₄F₈ sccm, SF₆ sccm	Profiles of lines exposed at 300 µC/cm2, etched 60s with recipe 'ProcessC'
	Pressure	mTorr, Strike: secs @ mTorr
	Power	W Coil Power, 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: ~300 nm/min 102 nm lines: ~250 nm/min
Etch rates	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	500 nm lines: nm/min 190 nm lines: nm/min 102 nm lines: nm/min 61 nm lines: nm/min
Etch rates	CSAR	nm/min

@@ Line 819: / Line 819: @@
 |Duration
 |2.5 s
-|rowspan="16" width="20%" | Profiles of lines exposed at 300 µC/cm2, etched 2:30 minutes (150s) with recipe 'nano1.42'
+|rowspan="16" width="20%" | Profiles of lines exposed at 300 µC/cm2, etched 6:00 minutes with recipe 'NBoost01'
-  [[File:617817 HD-4_11.png|200px]] [[File:617817 HD-4_18.png|200px]]
+  [[File:tigre 6.17 -15% 3a_ 11.png|400px]] [[File:tigre 6.17 3a_ 08.png|400px]]
-  [[File:617817 HD-4_16.png|200px]] [[File:617817 HD-4_14.png|200px]]
+  [[File:tigre 6.17 3a_ 20.png|400px]] [[File:tigre 6.17 3a_ 21.png|400px]]
+ [[File:tigre 6.17 3a_ 22.png|400px]]
 |-
 | width ="30"| Gasses