High Quality Mask Storage in an advanced Logic -Waferfab

Transcription

1 High Quality Mask Storage in an advanced Logic -Waferfab Carmen Jähnert, Silvio Fritsche Infineon Technologies Dresden GmbH Lithography

2 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

3 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

4 Introduction Mask is one key factor in Lithography Thousands of masks to be managed in Logic fabs at very long lifetimes & thousands of exposures Mask clean, defect-free and well in of use Mask degradation and damage must be avoided Fast access to required masks for exposure High Quality Mask Storage and Logistics is essential Haze prevention by XCDA Automated mask handling Efficient mask logistics by RFID

5 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

6 Fab Requirements with respect to Masks Stable mask quality over whole lifetime, no mask degradation Prevention of haze, contamination, pellicle damage, ESD damage safe and clean mask storage safe and clean mask handling and cleaning ESD protection in all mask handling areas well controled environment for all mask related areas Fast availability of each in multi-tool-landscape fast access, short transportation times, low operator effort correct mask for the given lot correct box and orientation related to exposure tool secure mask logistics Transparency of status and location-tracking for each mask

7 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

8 Mask Storage under XCDA Purge System: DMS M Prototype Capacity 3038 masks Storage of haze critical masks semi-bare under XCDA temperature and very low humidity

9 Advanced Mask DMS M Semi Bare Storage System / Prototype Capacity: 3038 masks in semi-bares, triple carousel Buffer for full and empty boxes, multiple loadports XCDA Purge in whole storage, handling and buffer area huge volume ~25m 3 Humidity <5%, temperature 23+/-0,5 C Full air circulation, two redundant drying systems Controlled air mask surface <1m/s ESD, particle & AMC protection, ISO class 2 Full automated mask and box handling in storage and buffer area by 2 different robots Front-View Buffer Loadports for Nikon-Boxes / SMIF-Pod

10 Advanced Mask DMS M Kuka-Robot Nikon-Port Opener ESD-Protection by Quad-Ionbars SMIF-Port Opener Handling-Area BC-Reading & Rotation Station Semi-Bare Station

11 Advanced Mask DMS M Storage Carousel with Semi-Bares Nikon-Buffer Kuka-Robot Handling and Storage Area

12 Monitoring concept AMC 3 Outlet Air Stocker AMC Test-Points Particle Test-Points Stocker Inlet Air AMC 4 Inlet Air Semibare Station Cleanroom AMC 2 Carousel Stocker Nikon Loadport AMC 1 Inlet Air Stocker-Up Stocker Outlet Air AMC and Particle-monitoring within the mask storage system

13 Airflow scheme with monitoring points Darts illustrating airflow Upwards Downwards Handling Area Storage Carousel Buffer and Loadports

14 XCDA Purge conditions Relative Humidity in % XCDA purge of whole inside space (carousel, buffer, handling-area, loadports) complete air circulation with 10% fresh air generated by 2 redundant drying systems FFUs, AMC inlet 24, , , ,5 21 Minimum Average Maximum Max Limit Temperature in C Temperature and Humidity monitoring data ( 4 weeks ) Overpressure : Storage area vs. fab Buffer vs. fab 3 Pa 0,5 Pa Relative humidity <5% Temperature 23 +/-0,5 C Air surface <1m/s (~ 0,6m/s) Stable Airflow, Temperature and Humidity in whole system in process

15 AMC and Particle-Monitoring Particle-monitoring, stocker Particle excursion due to damaged fan unit Amine and Sulfate-monitoring AMC2 carousel-stocker, AMC3 outlet-air stocker Internal IFD Spec: SO2 < 0,5ppb ; NH3 < 1ppb Particle-monitoring, stocker Stable performance after fan-unit exchange

16 Lessons learned System Optimizations Airflow and differential-pressure concept was re-adjusted Sealing of drying system in basement and storage system was significantly improved (pipes, doors, walls ) Installation of 3 additional cooling units in circulating air to obtain required temperature of 23 C Exchange of materials and installation of additional Quad-Ion Bars for ESD-safety Limitation of air velocity in whole area to max.1m/s to avoid ESD on mask surface at very low humidity Fine adjustment of Kuka robot speed to maintain Optimized air routing in service area and buffer to reach ISO2 spec Clean-up and conditioning of whole system after installation to reach ISO2 spec

17 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

18 Advanced Mask DMS M New Logistic Features High complexity due to fab-requirements different box-types, barcodes, pellicles, mask orientations Equipment integration via icada-rsm Workflows RSM Remote controlled, Web-based interface Automated box selection and mask orientation dedicated to order-tool Event-based single slot control and mask location tracking, authorized & secure access, different counters, storage groups definable Parallel workflows & parallel handling of robots Mask Insert, Unload, Reservation in parallel with Mask order from exposure tool to buffer short unload times <20sec RFID identifikation Mask identification via barcode (3 different types / positions: Nikon/Canon/ASML) Box identification via RFID -> write-in into box-rfid Box identification by and exposure tools -> fast and clean Multi-use of boxes, labelfree clean, cost efficient

19 Nikonbox with RFID RFID Stepper Nikonbox marker and RFID Mask Barcode & serial number is written into unload from stocker RFID Reader exposure tool low operator effort, safe, clean

20 Content Introduction Fab Requirements with respect to Masks Mask Storage under Purge Efficient Mask Logistics Conclusions / Benefits Outlook

21 Conclusions / Benefits Storage of haze-critical masks under XCDA purge ensures high mask quality and avoids mask degradation and haze Airflow, humidity and temperature are well controled and stable over long usage times even under high-frequent mask exchanges No issues with ESD or particle contamination after 3 years of usage No longterm degradation effects of pellicle, adhesive, backglas and materials induced by dry air purge RFID logistics with stocker and icada RSM well implemented; mask IDs, RFID-content, box-type and orientation always correct Workflows and hardware modules performing stable and reliable even under high load and permanent usage (~2000 masks, ~350 moves per day) Extended mask lifetimes, less mask degradation and damages Less line stops due to repells or replacement masks less costs No mask repeaters and mask driven defect issues stable Yield Efficient logistics, less mismatch improved Litho cycle times

22 Acknowledgement The authors gratefully thank Mr. Udo Widmann from DMS Dynamic Micro Systems and Dr. Michael Rüb, Mr. Peter Stark from MCRT GmbH for installation, evaluation and optimisation of the new system until production release. Many thanks to the very committed and constructive work from the icada counterparts Mr. Tobias Ferber, Mr. Alexander Zschach and Mr. Peter Schnebel for implementing efficient workflows and software features. Another big thank to Mr. Thomas Sebald from Estion GmbH for the high experienced ESD consulting and assessment. Last, we warmly thank our colleagues from Infineon Cleanroom Service Mr. Christoph Hocke and Mrs. Tina-Maria Kaden for supporting us during tool acceptance and implementation of the monitoring system as well as our Infineon litho experts Mr. Rainer Husse and Mr. Steffen Habel for their excellent support for system hook-up, installation and service support.

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