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C.JeynesC.Jeynes11, A.J.Smith, A.J.Smith11, N.Peng, N.Peng11, M.Zier, M.Zier 2 2, A. Morel, A. Morel 3 3, Q.Zhao, Q.Zhao 3 3, K.Temst, K.Temst 3 3, ,
W.VandervorstW.Vandervorst 3,4 3,4, A.Vantomme, A.Vantomme 3 3, A.Cassimi, A.Cassimi 5 5, I.Monnet, I.Monnet 5 5, E.Balanzat, E.Balanzat 5 5, R.Elliman, R.Elliman 6 6 1 University of Surrey Ion Beam Centre, Guildford, England*2 Forschungszentrum Dresden, Rossendorf, Saxony, Germany*3 Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven, Belgium*4 IMEC Kapeldreef 75, Leuven, Belgium*5 Commissariat à L’Energie Atomique, Caen, France*6 Australian National University, Canberra, Australia * SPIRIT partner providing Trans-National Access
Fluence Control in several European Ion Implanters
Ion Beam Centre
Fluence ControlFluence Control
Ion Implantation is one of the basic Ion Implantation is one of the basic enabling technologies for our huge enabling technologies for our huge semiconductor processing industry, semiconductor processing industry, because in principle we can because in principle we can ““count the count the ions inions in””. This project is designed to . This project is designed to demonstrate that the SPIRIT partners demonstrate that the SPIRIT partners (and others) can indeed supply their (and others) can indeed supply their users with a specified implanted fluence.users with a specified implanted fluence.
Surrey : Surrey : 2 implanters, 2 MV, 2 implanters, 2 MV, 200 kV (2 beam lines)200 kV (2 beam lines)
Rossendorf : Rossendorf : 4 implanters, 40 kV, 500 kV, 4 implanters, 40 kV, 500 kV, 200 kV, 3 MV Tandem200 kV, 3 MV Tandem
Leuven : Leuven : 2 implanters, 90 kV, 200 kV2 implanters, 90 kV, 200 kVCaen : Caen : 1 MeV/amu cyclotron1 MeV/amu cyclotronANU : ANU : 2 implanters, 150 kV, 2 implanters, 150 kV,
1.7 MV Tandem1.7 MV Tandem
Fluence Control and SPIRITSPIRITSPIRIT
SPIRIT (“SPIRIT (“Support of Public and Industrial Support of Public and Industrial Research Using Ion Beam TechnologyResearch Using Ion Beam Technology”) is ”) is supported by the European Community as an supported by the European Community as an Integrating Activity under EC contract 227012. Integrating Activity under EC contract 227012.
SPIRIT integrates 11 leading ion beam facilities SPIRIT integrates 11 leading ion beam facilities from 6 European Member States and 2 from 6 European Member States and 2 Associated States. 7 partners provide Associated States. 7 partners provide Trans-Trans-National Access National Access to their facilities, offering to their facilities, offering highly complementary equipment and areas of highly complementary equipment and areas of specialization to European scientists. Ions are specialization to European scientists. Ions are supplied in an energy range from below 10 keV supplied in an energy range from below 10 keV to more than 100 MeV for modification and to more than 100 MeV for modification and analysis of solid surfaces, interfaces, thin films, analysis of solid surfaces, interfaces, thin films, and soft matter. SPIRIT will increase the and soft matter. SPIRIT will increase the quality of research by sharing best practice, quality of research by sharing best practice, harmonizing procedures and establishing harmonizing procedures and establishing rigorous quality control measures.rigorous quality control measures.
Accurate Analysis(Right) Analysis Protocol based (Right) Analysis Protocol based on accurate stopping powerson accurate stopping powersWe have demonstrated previously that a-Si We have demonstrated previously that a-Si stopping powers are given correctly by SRIM03 stopping powers are given correctly by SRIM03 for 1.5 MeV He, by comparison with a for 1.5 MeV He, by comparison with a CRMCRM (certified reference material).(certified reference material).
Therefore the a-Si yield determines the Therefore the a-Si yield determines the charge.solid-anglecharge.solid-angle product for each spectrum at product for each spectrum at 0.6%, far better than the ~2% common in charge 0.6%, far better than the ~2% common in charge integration equipment.integration equipment.
Detector Detector electronicelectronic gaingain is critical to accuracy. It is critical to accuracy. It is astonishingly easy to make large errors (much is astonishingly easy to make large errors (much larger than expected) in the determination of this larger than expected) in the determination of this parameter.parameter.
A A double-detectordouble-detector configuration is always used configuration is always used specifically to validate the detector gain specifically to validate the detector gain calibration. calibration.
It also is a double check on It also is a double check on internal consistency internal consistency of the measurements, essential for analyses like of the measurements, essential for analyses like these.these.
Surrey will carry out the measurements Surrey will carry out the measurements for the whole project using (mostly) a for the whole project using (mostly) a published protocol. published protocol.
High energy implants require protocol variation.High energy implants require protocol variation.
C. Jeynes et al, Quality assurance in an implantation laboratory by high accuracy RBS,
Nucl. Instrum. Meth. B, 249 (2006) 482–485
(Below) Uncertainty Budget(Below) Uncertainty BudgetTraceably accurate analysis must be Traceably accurate analysis must be accompanied by a systematic analysis of all the accompanied by a systematic analysis of all the contributions to the uncertainty. In most contributions to the uncertainty. In most analyses this is dominated by uncertainty in analyses this is dominated by uncertainty in either collected charge or stopping power.either collected charge or stopping power.
Symbols: data; Lines: fitSymbols: data; Lines: fit
Samples and AnalysesSurreySurrey
• 100 mm wafers used in systematic QA 100 mm wafers used in systematic QA programme, fluence measurements programme, fluence measurements
for each beam line every quarterfor each beam line every quarter• Faraday cup validation requiredFaraday cup validation required• Measurements of three wafers (one Measurements of three wafers (one cycle) is completedcycle) is completed• Analysis of data almost completeAnalysis of data almost complete• Target is 2% accuracy and 2% Target is 2% accuracy and 2% uniformityuniformity
RossendorfRossendorf
• 100 mm wafers used.100 mm wafers used.• Faraday cup validation required for Faraday cup validation required for three implanters and current three implanters and current measurement assembly for the 4thmeasurement assembly for the 4th• Measurements of four wafers is Measurements of four wafers is completedcompleted• Target is 2% accuracy and 2% Target is 2% accuracy and 2% uniformity for 2 implanters (FCs), 5% uniformity for 2 implanters (FCs), 5% & 5% (FC on 3 MV), 10% and 10% on & 5% (FC on 3 MV), 10% and 10% on 200 kV 200 kV
LeuvenLeuven
• Machine problems have precluded Machine problems have precluded preparation of test samples so far.preparation of test samples so far.
CaenCaen
• Small targets (10 mm) Al foil samplesSmall targets (10 mm) Al foil samples• Charge collection validation requiredCharge collection validation required• Samples are prepared : 40 MeV Samples are prepared : 40 MeV 10101414Xe/cmXe/cm2 2 • Analysis of sample is complex : using Analysis of sample is complex : using
PIXE calibrated against low energy Xe PIXE calibrated against low energy Xe standard implants by Surrey, validated standard implants by Surrey, validated as standards by RBS under this as standards by RBS under this
programmeprogramme• Target is 10% accuracy and 5% Target is 10% accuracy and 5% uniformityuniformity
ANUANU
• Four 20 x 20 mm samples used.Four 20 x 20 mm samples used.• Current collection validation required Current collection validation required for for two implanters at both low and high two implanters at both low and high energies for eachenergies for each• Measurement of four samples is Measurement of four samples is completedcompleted• Target is 5% accuracy and 5% Target is 5% accuracy and 5% uniformityuniformity
One Example of Measurements
ConclusionsConclusions
• 0.980(5).100.980(5).101515As/cmAs/cm22
• No significant uniformity (better No significant uniformity (better than 2%)than 2%)• Absolute measurement accuracy Absolute measurement accuracy of mean value is 0.9%of mean value is 0.9%• Detectors agree within expected Detectors agree within expected uncertaintyuncertainty• 2% (12% (1) fluence accuracy achieved) fluence accuracy achieved
Table 4 : As signal, 2 detectors Corrected Weighted DetA DetB Average Average A/B Samples TFU TFU TFU TFU
1 0.95 0.96 0.96 0.96 0.9864 2 0.99 1.00 1.00 1.00 0.9903 3 1.03 0.99 1.01 1.00 1.0455 4 1.02 0.97 0.99 0.98 1.0510 5 0.96 0.97 0.96 0.97 0.9864 6 1.06 0.99 1.02 1.01 1.0672 7 1.03 0.94 0.98 0.97 1.1042 8 1.01 0.97 0.99 0.98 1.0442 9 0.95 0.96 0.95 0.95 0.9929 10 0.99 0.96 0.98 0.97 1.0283 11 0.98 0.98 0.98 0.98 0.9972 12 0.95 0.98 0.97 0.97 0.9711 13 1.03 0.96 1.00 0.99 1.0651
Average 0.996 0.972 0.984 0.980 1.0254 ActualSD 3.7% 1.8% 2.1% 1.8% 4.0% ExpectedSD 4.1% 1.7% 1.6% 1.6% 4.4%
Real Variation: 0.5% 1.5% 0.9% 0.0%
Err in Average 0.44% 0.44% 1.23% # measurements 13
TFU = “thin film units” = 10TFU = “thin film units” = 101515atoms/cmatoms/cm22
140 keV 10140 keV 101515As/cmAs/cm22 (Surrey) (Surrey)
• Line 1, DF (Danfysik) 200 kV implanterLine 1, DF (Danfysik) 200 kV implanter• Wafer QA59P#25 (measured March 2010)Wafer QA59P#25 (measured March 2010)• 13 spots over 100 mm wafer measured at 2%13 spots over 100 mm wafer measured at 2%• 2 detectors (1,5.3) msr, 40 uC per spot2 detectors (1,5.3) msr, 40 uC per spot• Channelled on substrateChannelled on substrate• Charge.solid-angle product determined per Charge.solid-angle product determined per detector from the a-Si height in the implanted detector from the a-Si height in the implanted regionregion• Weighted average of detectors used due to Weighted average of detectors used due to
poor counting statistics on the small detector Apoor counting statistics on the small detector A
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