Specific Process Knowledge/Thermal Process/Resist Pyrolysis furnace/Acceptance test

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Multipurpose Anneal furnace acceptance test

The acceptance for the Multipurpose Anneal furnace was performed in January 2015 by ATV Technologie and DTU Nanolab.

At the acceptance test a dry oxide layer was grown on a boat of 150 mm wafers. The oxide growth was repeated three times.

For each run the oxide thickness and refractive index were measured on three of the wafers, and the standard deviation and non-uniformity were calculated for each wafer, over the boat and from run to run. The results can be found below.

In November 2024 the furnace was repaired by ATV Technologie. At the repair, the whole furnace body was changed, and all heaters were replaced. Also, the process exhaust flow was decreased by changing a valve in the exhaust line.

After the repair, the oxidation process from the acceptance test was repeated and optimized. The positions of the control thermocouples (TCs) and the process exhaust were adjusted to minimize the non-uniformity of the grown oxide layer. The final optimized result can be found below.

Oxidation parameters

Recipe: "vr_dryOx_1050C_80min_150_5Wafer_D1_mit_Inliner_oPurgering.ATV" or ""vr_dryOx_1050C_80min_3Wafer_June2020.ATV" (same recipe parameters)

Oxidation time: 80 min

Temperature: 1050 ^oC (all temperature zones)

O₂ flow: 1 slm

The oxidation has been done with 150 mm wafers. The number of wafers in the boat was 30.

Wafer 4 (towards the door), wafer 16 (center wafer) and wafer 28 (towards the service area) were measured in 13 points using the M-2000V ellipsometer.

Results - Acceptance test 2014

Oxide thickness

	Date	Wafer 4			Wafer 16			Wafer 28			Center point only
		Average oxide thickness [nm]	St. deviation	Non-uniformity [%]	Average oxide thickness [nm]	St. deviation	Non-uniformity [%]	Average oxide thickness [nm]	St. deviation	Non-uniformity [%]	Average oxide thickness [nm]	St. deviation	Non-uniformity [%]
Run 1	28-01-2015	109.7	1.0	1.7	107.7	0.9	1.1	106.5	0.8	1.2	107.0	2.1	1.9
Run 2	28-01-2015	107.3	1.7	2.4	105.0	1.4	1.7	107.3	0.7	0.9	105.7	1.0	0.9
Run 3	30-01-2015	103.6	0.8	1.1	102.6	0.6	1.2	102.2	0.6	1.1	102.9	1.0	1.0
Average		106.9	1.2	1.7	105.1	1.0	1.3	105.3	0.7	1.1	105.2	1.4	1.3

Run-to-run
Average oxide thickness [nm]	St. deviation	Non-uniformity [%]
105.2	2.1	2.0

Refractive index

	Date	Wafer 4			Wafer 16			Wafer 28			Center point only
		Average refractive index	St. deviation	Non-uniformity [%]	Average refractive index	St. deviation	Non-uniformity [%]	Average refractive index	St. deviation	Non-uniformity [%]	Average refractive index	St. deviation	Non-uniformity [%]
Run 1	28-01-2015	1.46	0.00	0.04	1.46	0.00	0.07	1.46	0.00	0.06	1.4609	0.0004	0.0230
Run 2	28-01-2015	1.46	0.00	0.09	1.46	0.00	0.17	1.44	0.01	0.69	1.4561	0.0094	05873
Run 3	30-01-2015	1.46	0.00	0.06	1.46	0.00	0.05	1.46	0.00	0.07	1.4602	0.0004	0.0291
Average		1.46	0.00	0.06	1.46	0.00	0.10	1.46	0.00	0.27	1.46	0.00	0.21

Run-to-run
Average refractive index	St. deviation	Non-uniformity [%]
1.4591	0.0026	0.1637

Results - Furnace repair 2024

Oxide thickness

	Date	Wafer 4		Wafer 16		Wafer 28		Over the boat (all points)		Center point only
		Average oxide thickness [nm]	Non-uniformity [%]	Average oxide thickness [nm]	Non-uniformity [%]	Average oxide thickness [nm]	Non-uniformity [%]	Average oxide thickness [nm]	Non-uniformity [%]	Average oxide thickness [nm]	Non-uniformity [%]
Test	07-05-2024	108.1	0.96	108.7	0.95	109.8	0.98	108.9	0.76	108.2	1.22

Thermo couple (TC) position - Distance from the bell jar: 12 cm, 21.5 cm, 36 m