Specific Process Knowledge/Etch/ICP Metal Etcher/Chromium/Cr etch data from AS

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Test data on Cr etch development by Anders Simonsen @NBI.KU

Final recipe/result for Cr etch and etching down in the nitride in the AOE

The SEM images where done some after the Cr etch and some after both the Cr etch and the silicon nitride etch in the AOE using the recipe "SiN_AS". The important thing was to see how well the Cr works for masking the nitride given vertical and smooth sidewalls in the nitride.

Recipe	Pressure [mTorr]	Coil power [W]	Platen power [W]	Total Flow Cl2+O2 [sccm]	O2%	Temp		Time [s]	CSAR etch rate [nm/min]	CSAR rate w bond		Etch rate [nm/min]	Selectivity		coil load	coil tune	plat load	plat tune	Comment
test13/laqs	10	300	15	30	23.33	20		28	100.71			42.86	0.43						This recipe was chosen over no. 12 because it did not need a large over etch of the Cr (no foot).

• After Cr etch with recipe 13 with descum
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• After Cr etch 75s with recipe 13 and nitride etch in the AOE 20s
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• After Cr etch 75s with recipe 13 and nitride etch in the AOE 40s
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• After Cr etch 85s with recipe 13 and nitride etch in the AOE 20s
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• After Cr etch 90s with recipe 13 and nitride etch in the AOE 20s
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DOE experiments and results made on pattern free samples and samples patterned with UV lithography (SEM images)

Name	Pressure [mTorr]	Coil power [W]	Platen power [W]	Total Flow (Cl2+O2) [sccm]	O2 %	Selectivity	Etch-rate [nm/min]	Side-angle	Corner	Resist-damage	Etch time [s]	Etch depth [nm]		Angle1	Radius1	Angle2
t5	5	300	25	40	25	0.21	49.03	25.5	319.5	1	175	57		28	331	23
t7	15	300	15	40	15	0.61	52.15	12	154.5	1	130	87		14	159	10
t8	5	500	15	40	25	0.4	49.50	39.5	228.5	1	120	101		42	169	37
t4	15	500	25	40	15	0.39	70.80	19.5	201	1	100	82		21	158	18
t2	5	300	25	80	15	0.21	40.54	40.5	262.5	3	185	75		42	274	39
t10	15	300	15	80	25	0.68	58.00	11.5	87	2	120	84		14	70	9
t6	5	500	15	80	15	0.43	49.24	29.5	300	5	145	81		29	362	30
t9	15	500	25	80	25	0.41	80.67	18.5	134.5	2	90	79		20	155	17
t1	10	400	20	60	20	0.35	63.13	17.5	288	2	115	79		20	292	15
t1R	10	400	20	60	20	0.4	57.14	20	186	2	105	100		24	232	16

Sem images of the DOE

• Sample t5
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• Sample t7
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• Sample t8
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• Sample t4
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• Sample t2
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• Sample t10
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• Sample t9
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• Sample t1
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• Sample t1R
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Tests made after DOE with e-beam patterned samples

Recipe	Pressure [mTorr]	Coil power [W]	Platen power [W]	Total Flow Cl2+O2 [sccm]	O2%	Temp		Time [s]	CSAR etch rate [nm/min]	CSAR rate w bond		Etch rate [nm/min]	Selectivity		coil load	coil tune	plat load	plat tune	Comment
test11	15	300	15	40	25.00	20		23	80.87	73		52.17	0.65
test12	20	300	15	30	23.33	20		21	65.71	56		57.14	0.87						There seems to been a foot on the Cr after the Cr etch, therefor it was repeated for 2 min Cr etch to remove the foot
test13/laqs	10	300	15	30	23.33	20		28	100.71			42.86	0.43						This recipe was chosen over no. 12 because it did not need a large over etch of the Cr (no foot).
test14	10	300	15	40	25.00	20		30	88.00			40.00	0.45
nano	5	500	15	60	0.17	10		33	99.00			36.36	0.37		41	52	31	50	With strike pressure
langman	10	500	25	40	0.20	8		21	168.39			57.14	0.34		42	52	35	53	With strike pressure

SEM images of the tests after the DOE

These SEM images where done after both the Cr etch and the silicon nitride etch in the ICP metal using the recipe "Slow etch with carrier". The important thing was to see how well the Cr work for masking the nitride given vertical and smooth sidewalls.

• Sample test11
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• Sample test12 1 min etch in Cr
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• Sample test12 2 min etch in Cr
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• Sample test13
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• Sample testnano
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• Sample elangman
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