Specific Process Knowledge/Thin film deposition/Deposition of polysilicon/Deposition of polysilicon using LPCVD/Standard recipes, QC limits and results for the 4" polysilicon furnace

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Standard recipe on the 4" polysilicon furnace (this recipe is being watched in the in the quality assurance program):

Quality Controle (QC) for the 4" polysilicon furnace

The QC procedure for the 4" LPCVD polysilicon furnace The newest QC data for the 4" polysilicon furnace QC Recipe "POLY620" Standard polysilicon Wafer size and number of wafers 4" wafers 30 wafers in a run Deposition time 30 min SiH4 (silane) flow 80 sccm Pressure 200 mTorr Temperature (zone 1, 2, 3) 625oC, 618oC, 625oC QC limits 4" wafers Polysilicon deposition rate and non-uniformity over one wafer 9.34 - 10,18 nm/min < 2.0 % Polysilicon deposition rate and non-uniformity over the boat nm/min < 5.0 %

Expected results when using the standard recipe on the 4" polysilicon furnace:

	QC Recipe	Polysilicon deposition rate [nm/min]	Uniformity of the polysilicon deposition rate [%]	Refractive index	Uniformity of the refractive index [%]
Over one wafer 4" wafers Average values, Jun. 2011. - Sep. 2013	"POLY620"	10.60	0.91	3.93	0.36
Over the boat 4" wafers Average values, Jun. 2011. - Sep. 2013	"POLY620"	10.34	3.08	3.89	2.84
Over one wafer 4" wafers Average values, Mart 2015 (After changing process temperature)	"POLY620"	9.77	1.57	3.9578	0.63
Over the boat 4" wafers Average values, Mart 2015 (After changing process temperature)	"POLY620"	9.60	1.65	3.960	0.66

Process parameters for the standard recipes on the 4" LPCVD polySi furnace:

Recipe name	Wafer size and number of wafers	PolySi thickness [nm]	Temperature [oC]	Pressure [mTorr]	SiH4 gas flow [sccm]	B2H6 gas flow [sccm]	PH3 gas flow [sccm]	Comments
"POLY620"	4" wafers 1-30 wafers	0 - 2000	620	200	80	0	0
"POLYBOR"	4" wafers 1-30 wafers	0 - 2000	620	200	80	7	0	New recipe name September 2012 (before "POLY620PX").
"POLYPHOS"	4" wafers 1-30 wafers	0 - 1000	620	200	80	0	7	New recipe name September 2012 (before "TH3POLY").
"AMORF580"	4" wafers 1-30 wafers	0 - 2000	580	250	80	0	0
"AMORF560"	4" wafers 1-30 wafers	0 - 2000	560	250	80	0	0
"AMORBOR"	4" wafers 1-30 wafers	0 - 2000	580	250	80	7	0
"AMORPH3"	4" wafers 1-30 wafers	0 - 2000	580	250	80	0	7

Expected results when using the standard recipes on the 4" LPCVD polySi furnace:

These are typical values

Recipe name	Deposition rate [nm/min]	Refractive index@630nm	Thickness variation on center wafer	Thickness variation along the boat	Surface roughness [nm] or SEM images	Boron concentation [boron atoms/cm3]	Comments
"POLY620"	~ 10-12	~ 3.9	< 2%	< 5%			See quality control data for latest measurements
"POLYBOR"	~ 10-12					~ 1018 boron atoms/cm2. Azeem Zulfigar, DTU Nanotech, Feb. 2013. Boron concentration measured by SIMS through a ~50 nm boron doped polySi layer. The high boron concentration at the polySi-oxide interface is caused by a 5 min. B2H6 flow before the SiH4 flow starts.
"POLYPHOS"	~ 2
"AMORF580"	~ 4
"AMORF560"	< 4				Measured by AFM for 234 nm amorphours polySi: Rq: 0.417 nm Ra: 0.331 nm AFM image for surface roughness measurement. 234 nm polySi deposited using the "AMORF560" recipe. Anders Simonsen, KU, May 2016
"AMORBOR"	~ 5
"AMORPH3"	~ 1
"AMOR540" (requires a special permission)	~ 1.4				Cross section image by SEM: SEM image for thickness measurement. 2 um amorphous polySi deposited using the "AMOR540" recipe and 24 hours deposition time. Lars Kildebro, NILT, June 2020

The deposition rate changes a little over time, but generally it is fairly good from run to run. The last measured values of the polySi thicknesses can be found on the POLY page in the Furnace logbook and in the quality control data (only standard polySi).