Oerlikon PVD production solution for in-situ large scale deposition - PowerPoint PPT Presentation

Oerlikon PVD production solution for in-situ large scale deposition of PZT 2nd International Workshop on Piezoelectric MEMS Materials - Processes - Tools - Devices Lausanne, 06./07.09.2011 M. . Kr Kratzer er , L. Castaldi and B. Heinz Oerlikon Systems R&D, Liechtenstein D. Kaden, H.J. Quenzer Fraunhofer ISIT, Germany A. Mazzalai, S. Harada, P. Muralt EPFL, Switzerland

Agenda § piezoVo oVolume pro roject t § Sputter e er equipment nt § Key hardware are fac actors ors § Results s of in-situ PZT T deposition process cess § Summ mmar ary and nd out utlook ok 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

EU projec ect “pi piezoVolume” e” Sputt tter coo ooperation and go goals ls Devel elopment of a aut utomated high h volume vo e sp sputt tter system em F. Tyholdt - 14:00 M. Kratzer, L. Castaldi and B. Heinz FP7 piezoVolume Pro roce cess ss devel elopment nt Pro roce cess ss devel elopment nt A. Mazzalai, S. Harada and P. Muralt D. Kaden and H.J. Quenzer Overvi Ov view ew Goal of this cooperation is to develop in-situ tu PZT processes on a Oerlikon sputter system which meet commercial production requirements Pro roject ect High quality PZT films on 8” substrates § Dielectric constant ~ 1200 and dielectric loss tan δ < 0.03 goals go ls § Piezoelectric coefficients d 33,f > 100pm/V and - e 31,f > 14 C/m2 § Thickness uniformity < ± 5% at max. thickness 4 - 5 µm § Throughput > 3.6 wafer/hr·µm (= 1nm/s) 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Equip ipment for PZT in-s -situ sputt ttering ng RF magnetron sputt ttering from single ce ceramic target et CLN20 200 sputte ter tool ool RF sputte ter mod module e e equipp pped with h 8” Very Hot t Chuck ck Robot handling D C A Support stations Aligner (A) Loadlocks Degasser (D) Cooler (C) 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Key hardware facto tors rs Overview ew Anode & Shi hieldings gs PZT sputter equipment RF ca cath thode de Hea eated chu huck ck RF B Bias & & mast ster oscill illator or Ma Magnet arr rray & Targ rget et 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Key hardware facto tors rs Very Hot ot Chu huck ck Heated substrate holder for 6” and 8” wafer enable deposition process in the temperature range needed for in-situ sputtered PZT films 6” Very Hot t Chuck ck Temperature sense wafer vs. Heater set point (6" and 8" Very Hot Chuck) 650 6" wafer 600 8" wafer Temperature_sense wafer [°C] 550 8” Very Hot t Chuck ck 500 450 Operational 400 range 350 450 500 550 600 650 700 750 800 850 Heater set point [°C] 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Key hardware facto tors rs Temperature un uniformity 8” Very Hot ot Chu huck ck Optimization of process settings to achieve highest wafer temperatures and excellent temperature uniformity by § Back gas flow § ID / OD heating (Alpha factor) 100 Measurement Statistics Uniformity 458.0-460.0 Temperature (Temperatur) Uniformity 2.44% 456.0-458.0 uniformity 80 454.0-456.0 Mean 430.76 [°C] 60 452.0-454.0 Range 10.50 [°C] 450.0-452.0 Max 434.70 [°C] 40 448.0-450.0 Min 424.20 [°C] 446.0-448.0 20 y [mm] 444.0-446.0 0 442.0-444.0 440.0-442.0 -20 8” Very Hot t Chuck ck 438.0-440.0 436.0-438.0 -40 434.0-436.0 -60 432.0-434.0 430.0-432.0 -80 428.0-430.0 -100 426.0-428.0 Chuck temperature: 600°C -100 -80 -60 -40 -20 0 20 40 60 80 100 424.0-426.0 Backside gas: 4 sccm x [mm] 422.0-424.0 420.0-422.0 Wafer temperature: 430 °C 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Key hardware facto tors rs RF target self bi bias voltage ge 1. RF F power er 0 Target self bias voltage influenced by 1 kW 2 kW -50 3 kW Target self bias voltage [V] § Process pressure -100 § RF power -150 § Anode area B -200 A -250 d B RF C d A Plasma -300 0 10 20 30 40 50 60 70 80 90 100 110 C S U B U A Ar flow [sccm] U SB 2. Anode a e area ea 0 Higher anode area U Plasma -50 Cathode area ~ Anode area ea Target self bias voltage [V] Lower anode area -100 U B Cathode area < Anode area ea -150 U A U SB -200 U SB SB = U U A - U - U B -250 U B = U U Plasma ma -300 ea A ) n U A / U U B = ( (Area ea B / Area 0 10 20 30 40 50 60 70 80 90 100 110 Ar flow [sccm] 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

Key hardware facto tors rs Magnetron design gn Thickne ness un uniform Thickness uniformity of PZT films on Pt substrates ormity ty 1.15 PZT thickness and composition uniformity 1.10 influenced by Normalized thickness 1.05 § Erosion profile Uniformity § Emission characteristic of sputtered 1.00 atoms 0.95 § Scattering (~ pressure · distance) § Standard setup Standard 0.90 § Improved setup Improved § Substrate temperature 0.85 0 10 20 30 40 50 60 70 80 90 100 Radius [mm] Actual sputter performance Composition un uniformity y 1.03 § Deposition rate > 40 nm/min 1.02 § Estimated target life time ~ 1600 µm Composition (normalized) ID OD film thickness for 4mm target 1.01 1.00 0.99 0.98 0.97 620°C, ID 620°C, OD 1.000 1.004 Pb/(Zr+Ti) 1.000 0.989 Zr/(Zr+Ti) 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

In In-s -situ PZT deposition proce cess ss General trends ds Variation of substrate t e temp mperatu ature re 1.40 Relative Pb content can be influenced 1.20 Composition (normalized) § Pb decrease with temperature increase 1.00 0.80 § Pb decrease with Ar flow increase 0.60 § Pb increase with RF power increase Pb/(Zr+Ti) i) 0.40 Zr/(Zr+Ti) i) 0.20 0.00 500° C 550° C 600° C 650° C 700° C 750° C Variation of RF po power er Variation of Ar flow ow 2.00 1.40 1.80 1.20 1.60 Composition (normalized) Composition (normalized) 1.00 1.40 Pb/(Zr+Ti) i) 1.20 0.80 Zr/ r/(Zr+Ti) i) 1.00 0.60 0.80 Pb/(Zr+Ti) i) 0.60 0.40 Zr/ r/(Zr+Ti) i) 0.40 0.20 0.20 0.00 0.00 50 sccm 100 sccm 250 sccm 350 sccm 1.5 kW 2.0 kW 2.5 kW 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

In-s -situ PZT deposition proce cess ss 6” PZT w with PTO seed layer er § Best PZT films achieved with a Perfor ormanc ance of fil ilms depo posited at at 2 kW kW PTO seed layer to promote the nucleation of the PZT perovskite structure § For films sputtered at 1 kW § ε ~ 1500 § tan δ = 3.2% § d 33,f = 100pm/V § -e 31,f = 7.5 C/m 2 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com

In-s -situ PZT deposition proce cess ss 8” PZT w with TiO iO 2 see eed layer er § Best piezoelectric data 50 40.02, Pt (111) 69.132, Si (400) T h = 600°C 40 § ε ~ 1200 30 2 ] § tan δ = 3% Polarisation [µC/cm 20 Intensity [a.u] 10 § d 33,f = 120 pm/V 0 85.71, Pt (222) 38.25, PZT (111) 44.88, PZT (200) -10 55.47, PZT (211) § -e 31,f = 12.6 C/m 2 -20 E c (avg) = 49.6 kV/cm P rem (avg) = 23.5 µC/cm 2 -30 P max (avg) = 42.5 µC/cm 2 § Similar performance for films -40 -50 without TiO 2 seed layer -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 25 30 35 40 45 50 55 60 65 70 75 80 85 90 Field [kV/cm] 2 Theta Di Displac acement ent vs. . voltage ge Polarisat ation vs. displacement nt 4.0 0.05 T h = 600°C T h = 600°C 0.04 3.5 0.03 3.0 Polarisation [µC/cm2] Displacement [nm] 0.02 2.5 0.01 2.0 0.00 1.5 -0.01 1.0 -0.02 0.5 => d 33,f = 120 pm/V => d 33,f = 120 pm/V => e 31,f = 12.6 C/m 2 -0.03 => -e 31,f = 12.6 C/m 2 0.0 -0.04 -0.05 -0.5 -2000 -1500 -1000 -500 0 500 1000 1500 2000 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 Voltage [V] Displacement [nm] 2nd International Workshop on Piezoelectric MEMS - Lausanne, 06./07.09.2011 M. Kratzer, Oerlikon Systems R&D, e-mail: martin.kratzer@oerlikon.com