The Business of Science® Early production testing of 450mm process modules Mike Cooke Oxford Instruments Plasma Technology © Oxford Instruments 2014 CONFIDENTIAL Page 1 The problem The Business of Science® Fabs not planned Don’t invest in 450mm tools Tools not ready for 450mm Don’t invest in Fabs © Oxford Instruments 2014 CONFIDENTIAL Page 2 The current solution – public money The Business of Science® Fabs not planned Don’t invest in 450mm tools Tools not ready for 450mm Don’t invest in Fabs © Oxford Instruments 2014 CONFIDENTIAL Page 3 Alternative? The Business of Science® Sell a 450mm compatible tool to another sector Fabs not planned Don’t invest in 450mm tools Tools not ready for 450mm Don’t invest in Fabs Qualify a 450mm tool in another sector © Oxford Instruments 2014 CONFIDENTIAL Page 4 Productivity: synergy with silicon The Business of Science® 500 450 Substrate diameter mm 400 350 300 Silicon HBLED 250 200 150 100 50 0 1960 1970 1980 1990 2000 2010 2020 Single wafer 450mm silicon tools are also large batch tools for HBLED © Oxford Instruments 2014 CONFIDENTIAL Page 5 Difference – batch tool uses carrier plates The Business of Science® Carrier plates also require development – patent applied for PCT/GB2014/050162 How to get good heat transfer and minimum edge exclusion in a batch carrier? © Oxford Instruments 2014 CONFIDENTIAL Page 6 Process flow - HBLEDs The Business of Science® Substrate Patterned sapphire, SiC, Si... Epitaxy MOCVD HVPE Front End Processing Patterning,Etch, Passivation, Contact metallisation Back End Processing Backside thinning, Laser lift off, Dicing ,Phosphor encapsulation Final packaging © Oxford Instruments 2014 CONFIDENTIAL Page 7 Patterned sapphire substrate (PSS) The Business of Science® Substrate Etching: - Improves light extraction - Assists epitaxial growth Process requirement: - Low pressure BCl3 etch - High ion flux - High ion energy PR GaN PSS Sapphire substrate with PR mask © Oxford Instruments 2014 Highly controlled dry etch CONFIDENTIAL GaN-on-PSS Page 8 High ion flux etcher design – pancake coil The Business of Science® Uniform plasma over >50% of the chamber bore Plasma density > 1E17 m-3 close to the wafer – for hard material etching Dielectric induction window >0.5m diameter, ~2 tonnes air pressure load High RF power delivery (~3kW) to a large etch table © Oxford Instruments 2014 CONFIDENTIAL Page 9 Batch tools need carrier plates The Business of Science® Sapphire Wafer to Selectivity to Within Batch Etch rate Wafer Repeatibility PR wafer unif (nm/min) unif 14 x 4” 105 0.6:1 +/-3% +/-3% 48 x 2” 115 0.75:1 +/-3% +/-3% © Oxford Instruments 2014 +/-3% Etch Rate (nm/min) Uniformity PSS 100 +/-3% GaN 150 +/-3% AlGaInP 400 +/-3% CONFIDENTIAL Page 10 48 x 2” PSS Etch Profile – Astrea etcher The Business of Science® Inner wafer Before etch Mid wafer After partial etch Outer wafer MF 1mm © Oxford Instruments 2014 MF 2mm MF 5mm Centre CONFIDENTIAL OMF 5mm OMF 2mm OMF 1mm Page 11 Design for service The Business of Science® • Rail access capability for fast cleaning © Oxford Instruments 2014 CONFIDENTIAL Page 12 Design for maintenance The Business of Science® • Access to upper chamber area © Oxford Instruments 2014 CONFIDENTIAL Page 13 The Business of Science® • Access to etch table © Oxford Instruments 2014 CONFIDENTIAL Page 14 Batch PECVD The Business of Science® Process module Cool down Station (PECVD) © Oxford Instruments 2014 CONFIDENTIAL Cassette load lock Page 15 PECVD chamber after 250 runs The Business of Science® • Successful scaling and process transfer from 300mm • Some materials issues identified and overcome © Oxford Instruments 2014 CONFIDENTIAL Page 16 Carrier plate temperature The Business of Science® 10mins preheat then 10mins pump, x 3 times 61x2" platen (60µm dished) 61x2" platen (60µm dished) 300 400 350 Temperature (deg C) Temperature (deg C) 250 200 150 Platen Centre Platen Edge 100 Table Centre wafer 50 300 250 200 Platen Centre 150 Platen Edge Table 100 Centre wafer 50 Edge wafer 0 Edge wafer 0 0 1000 2000 3000 Time (secs) 4000 5000 6000 0 1000 2000 3000 Time (secs) 4000 5000 6000 •Carrier plate heat up time must be considered for throughput •Wafer temperature tracks carrier plate temperature closely •Carrier and table flatness are critical © Oxford Instruments 2014 CONFIDENTIAL Page 17 Faster in situ plasma cleaning The Business of Science® PECVD cleaning process Average table etch rate (nm/min) Average wall etch rate (nm/min) Baseline Optimised 417 733 26 31 Task 5.6.2 PECVD module progress Turning up the power increased etch cleaning rate but hit plasma stability limits Automatic end point using OES © Oxford Instruments 2014 CONFIDENTIAL Page 18 Deposition Rate stability with plasma cleans The Business of Science® PlasmaPro 1000 SiO2 © Oxford Instruments 2014 CONFIDENTIAL Page 19 Summary The Business of Science® • Batch production can motivate process module development before a 450mm market exists • Batch production debugs the modules • But requires other developments, e.g. Carrier plates © Oxford Instruments 2014 CONFIDENTIAL Page 20
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