Innovative partnership offers benefits for all

Transcription

1 2007 Spring Edition ASML s customer magazine Innovative partnership offers benefits for all Smart Service enables best-in-class support Paving the way to sub 40-nm imaging and double patterning

2 Editor s note images Colofon 4 ASML in the News 6 EUV development progressing well with first 32-nm images 8 TWINSCAN XT:1900i: paving the way to sub 40-nm imaging and double patterning 10 Immersion An approach to defect reduction 12 Smart Service enables best-in-class support 14 XT:1400 shipments top Innovative partnership offers benefits for all Editorial Board Don Crabtree, Peter Jenkins, Angelique Paulussen-Hoogakker Publisher Ryan Young Managing Editor Saskia Boeije Editor Emma English Contributing Writers Stuart Cherry, Richard Droste, Jos de Klerk, Rard de Leeuw, Jos Maas, Hans Meiling, MiPlaza, Robert O Neill, Rian Rubingh, Richard Visser, Christian Wagner, Jan-Evert van de Wetering, Ryan Young, Stuart Young, Fränk Zwaans 2007, ASML. ASML, ASM Lithography, TWINSCAN, PAS 5500, PAS 5000, SA 5200, ATHENA, QUASAR, HydroLith, IRIS, FOCAL, CPL, DDL, Micralign, Micrascan, 3DAlign, 2DStitching, 3DMetrology, MaskTools, LithoGuide, MaskRigger, MaskWeaver, LithoCruiser, LumenShaper, Ultra-k 1, DoseMapper, SAMOS, ILIAS, PerfectWave, AGILE, LS match2, ModelTuner, CLASS and the ASML logo are trademarks of ASML Holding N.V. or of affiliate companies. The trademarks may be used either alone or in combination with a further product designation. StarLith, AERIAL, AERIAL II, AERIAL E and AIMS are trademarks of Carl Zeiss. Nothing in this publication is intended to make representations with regard to whether any trademark is registered or to suggest that any sign other than those mentioned should not be considered to be a trademark of ASML or of any third party. 18 Reticle availability increasing good-wafers per day Circulation Michelle Herrick, Saskia Boeije, Emily Leung 20 An introduction to photolithography - Imaging For more information, please see:

3 ASML Images, Spring Edition 2007 Editor s note Immersion lithography now used in volume production by Ryan Young In December 2003, ASML announced that TSMC had placed the industry s first order for an immersion lithography system, a TWINSCAN XT:1250i. That system and others to follow over the next three years were used for early learning and process development. Fast forward to April 2007: ASML has now shipped more than 40 immersion systems to customers. These include TWINSCAN XT:1700Fi systems which are now being used in volume production by leading Flash manufacturers. In mid-2007 we will ship the first TWINSCAN XT:1900Gi with the industry s largest numerical aperture of This system is designed for 40-nm production. At SPIE Advanced Lithography we presented 36.5-nm images from this system. In addition, ASML and several of our customers have demonstrated defectivity data within production specifications. You can get the details in the feature article. Moving on to EUV, which was of course a big topic during SPIE, ASML showed 32-nm dense lines and 32-nm contact holes from our EUV alpha demo tools (ADT). Two EUV ADTs were shipped to customers in August With the integration of the two ADTs and the first resist images, EUV is on track for process development for the 32-nm half-pitch node in 2009, and for volume production in An update of the status and outstanding challenges is presented in this edition. To maximize the value customers can extract from our lithography systems, ASML has developed a smart service program that reduces system downtime and accelerates repair response time through Global Remote Competency Centers. Read more about it on page 12. Wafer stage speed is always the top of any productivity discussion, but reticle availability is a contributor as well. ASML s ongoing system improvement programs are engaged in getting the right reticle, cleaned and in place faster, increasing overall system performance and providing support for ultra-high throughput. ASML works hard to develop strong relationships with customers. We are pleased when we can contribute to customer success stories, and appreciate Philips MiPlaza and Cytocentrics for sharing one such story in this issue. You know you ve done something right when you pass a milestone such as 100 system shipments for a particular model. The XT:1400 has proven itself worthy of the title of industry workhorse across multiple applications. Building on this success, we have equally high expectations of the XT:1450 to deliver uncompromising value to customers. Lastly, in this issue we continue the Intro to Photolithography series we began last fall. This issue s article presents and explains the first of three key litho performance competencies: imaging. As always, I hope you find Images informative and of value. You re always welcome to provide direct feedback so that we can continuously improve the magazine. Please send your feedback to ryan.young@asml.com 3

4 ASML in the News Hynix Adopts ASML s LithoCruiser for Advanced Process Development November 30, 2006 ASML announced that Hynix Semiconductor Inc., one of the world s leading memory manufacturers, has standardized on ASML s LithoCruiser software for the company s process development activity. Hynix has purchased multiple licenses of LithoCruiser to perform lithography simulation and optimization for critical layers in all sub-60-nanometer DRAM and flash memory devices. ASML Extends ArF Leadership and Enables Double Patterning Development with New TWINSCAN XT:1450 December 5, 2006 ASML introduced its newest TWINSCAN system, an advanced 193-nanometer (nm) exposure system which features imaging, overlay and throughput improvements. The TWINSCAN XT:1450 is targeted for high volume manufacturing, an extension of dry ArF to sub-60-nm. It can also used by customers to support development of 32-nm node processes using double patterning techniques. The XT:1450 is the most advanced system for dry ArF volume production. It improves value of ownership for IC manufacturers, with an increased throughput of 143 wafers-per-hour under volume manufacturing conditions. The new AERIAL-P illuminator supports high efficiency polarization which, together with increased lens aberration control and enhanced overlay performance, enables the XT:1450 to extend the limits of dry ArF to a specified resolution of 57-nm. 4

5 ASML Images, Spring Edition 2007 For complete information regarding these press announcements, please refer to the press section of ASML Sets Two New Lithography Milestones at SPIE February 26, 2007 ASML announced that they will present record imaging results for immersion and extreme ultraviolet (EUV) technologies during SPIE Microlithography ASML will show two sets of breakthrough lithography results at the annual conference including 37-nm dense lines produced on the TWINSCAN XT:1900i, and both 32-nm dense lines and 32-nm dense contact holes from ASML full field EUV Alpha Demo Tools (ADT). ASML Completes Acquisition of Brion Technologies March 8, 2007 ASML announced that it has completed its acquisition of Brion Technologies, Inc., a leading provider of semiconductor design and wafer manufacturing optimization solutions for advanced lithography. We are pleased to welcome Brion into our company, said Eric Meurice, president and CEO of ASML. Brion s products and technology will complement and reinforce ASML s core lithography business, while ASML will help to accelerate Brion s growth into the growing market for Verification, Reticle Enhancement Technology (RET) and Optical Proximity Correction (OPC), by providing key lithography know-how. ASML to Establish Center of Excellence in Taiwan Our customers require new technologies to get them beyond the 45-nm node, said Martin van den Brink, executive vice president marketing and technology at ASML. The industry s first full-field EUV results from a customer site, coupled with the best resolution achieved to date for immersion demonstrate how our technologies continue to support our customers and their respective roadmaps. April 4, 2007 ASML announced that it has signed a contract with the Taiwanese Ministry of Economic Affairs (MOEA) to establish the ASML Center of Excellence (ACE) near Taipei. This follows the Letter of Intent ASML and MOEA signed late last year; ASML expects that ACE will be fully operational in Q after construction is scheduled to be completed. ASML is currently recruiting personnel for ACE and has secured a temporary facility. ACE will reinforce ASML s commitment to customers in the Asia-Pacific region by focusing on technology and applications development, equipment support, training, logistics, and refurbishment. ACE will also enable local sourcing of equipment modules, components and services.

6 EUV development progressing well with first 32-nm images By Hans Meiling Abstract Using a recently shipped 0.25-NA Alpha Demo Tool, we have produced the industry s first full-field EUV resist images, printing 32-nm half-pitch dense lines and spaces as well as 32-nm dense contact holes. While there are still many challenges to be solved, these images show that EUV lithography is well on its way for 32-nm half-pitch production. Some recent announcements to the press have cast doubt over when, or even if, EUV lithography will be ready for production. However, new results from ASML show that EUV is developing on schedule, and at a similar rate to previous wavelength technology introductions such as ArF. ADTs up and running As mentioned in the previous issue, we have already shipped two Alpha Demo Tools (ADTs): one to IMEC in Leuven, Belgium and one to the College of Nanoscale Science and Engineering of the University at Albany (CNSE) in the USA. These full-field (26 x 33 mm), step-and-scan tools will be used by these customers, their partners (more than ten semiconductor manufacturers) and ASML for process development and to establish the foundations for commercializing EUV lithography. The EUV ADTs are partly based on our proven TWINSCAN platform with key modules housed in vacuum chambers for EUV use. The ADTs optical train features a Projection Optics Box (POBox) developed in conjunction with Carl Zeiss. The POBox has a numerical aperture (NA) of 0.25 and offers good flare and aberration control. Tin-based electrical discharge sources are the most likely candidate for delivering sufficient in-band EUV power for production at an acceptable costs. Therefore both ADTs have been equipped with discharge-produced-plasma (DPP) tin-sources, enabling early experience in the design and optimization of these tin-based sources. Seeing is believing Using one of these EUV ADTs with a low-power xenon tooling source, we have taken the first resist images including 35-nm half-pitch lines with a DOF > 160 nm, 32-nm dense lines with a DOF > 80 nm and 32-nm dense contact holes. (See Fig. 1 & 2) The first resist images include 32-nm dense lines and contact holes Although impressive, these images are far from the limit of what is possible with EUV lithography. However, they do show that working EUV tools already exist and emphasize the feasibility of EUV for the 32-nm half-pitch node. Challenges ahead As with any lithography wavelength shift, delivering tools is only part of the story. In addition to further development of the source, there are still a number of associated infrastructure issues to be addressed before EUV lithography heads into production. The two main areas of investigation involve reticles and resists. Source developments The key issues around EUV sources are the power output and debris mitigation. Current power levels are significantly below those needed for volume production and EUV source suppliers are involved in ongoing projects to boost power levels. At the same time, ASML and source suppliers are investigating ways to mitigate the debris created by these sources. Improved debris mitigation will enable existing sources to be run at higher power without damaging the collector optics, and will be essential for production-level systems. 6

7 ASML Images, Spring Edition 2007 Reticle developments While the challenge of patterning reticles for 32-nm lithography is common to all technologies, EUV requires a shift to reflective reticles. ASML has been active in identifying the critical requirements for EUV mask blanks. Current champion data from suppliers show that today s EUV mask blanks meet almost all of these requirements, although more work is needed to reduce defect levels (See Fig. 3). -40nm NF +40nm 36 nm 34 nm 32 nm dense CH dense CH dense CH Figure 1: SEM pictures showing >80 nm depthof-focus for 32 nm hp lines/spaces. The focus step is 40 nm (MET-2D resist, dose ~24 mj/cm 2 ; NA = 0.25; σ = 0.5 conventional illumination, no OPC on mask). Figure 2: SEM pictures showing excellent dense contact hole printing capability down to 32 nm (MET-2D resist, dose ~40 mj/cm 2 ; NA = 0.25; σ = 0.5 conventional illumination, no OPC on mask). Resist developments The ITRS has specified technologyindependent resist requirements for 32-nm half-pitch patterning. These include sensitivity, resolution and line edge roughness. A number of EUV resists are already available, and while none yet meet all the ITRS requirements, current performance is encouraging given the timeline for the introduction of EUV (See Fig. 4). A bright future Clearly, there is still work to be done before EUV is ready for full production. However, following the introduction of the ADTs and with production tools in sight, development work on areas like masks and resists will accelerate as demand for these products increases as happened with earlier wavelength transitions. With the integration of the two ADTs and the first full-field resist images, EUV is on track for process development at the 32-nm half-pitch node in 2009 and volume production in 2011, putting its overall introduction timescale on par with the introduction of earlier technologies such as ArF. ASML is at the forefront of EUV development, and currently has orders f or three pre-production EUV systems to begin shipping in Supplier Normalized Requirements Resist Thickness (nm) Resolution (nm) Dose (mj/cm²) LWR (@Res) Goal MET2D PMMA Defects (final) Multilayer Defects Substrate Defects Reflectivity (uniformity) ML Wavelength Accuracy Supplier A Supplier B Requirements a b c a b a b a Flatness (back) Figure 3: Many mask blank parameters meet 32nm production requirements, but defect reduction remains the key challenge ML Bandwidth Reflectivity (actinic) CTE Uniformity Flatness (front) Surface Roughness (front) CTE Mean Surface Roughness (back) Merit Function Figure 4: EUV resists from four suppliers and results achieved over the last year showing sub 32nm resolution and dose sensitivity below 10mJ/cm 2 as feasible

8 TWINSCAN XT:1900i paving the way to sub 40nm imaging and double patterning by Christian Wagner, Richard Droste, Jos de Klerk Abstract The TWINSCAN XT:1900Gi will begin shipping in mid This system is a natural extension of the XT:1700Fi and supports the continued drive for device shrinks that the semiconductor industry requires by offering 40nm half-pitch resolution. This system features a projection lens based on the already proven in-line catadioptric lens concept but with an enhanced, industry leading NA of Overlay is improved to 6nm single machine, and using the system in chuck dedication mode down to well below 5nm, making it an enabler for double patterning applications for 32nm and below. Proven technology and design The XT:1900Gi is built on the established TWINSCAN platform. More than 500 TWINSCAN systems have shipped and the platform s mature technology reduces risks and improves reliability. What s more, the TWINSCAN platform s dual-stage architecture, together with the XT:1900Gi s increased scan speed of 600 mm/s, enables high-volume throughputs up to 131 wafers per hour. The XT:1900i uses the same HydroLith immersion technology as the XT:1700i and combines it with a new, very-high NA (1.35) projection system. (See Fig. 1) The Starlith 1900i projection lens is the fifth generation of 193 nm immersion lenses and the second catadioptric lens from Carl Zeiss. This lens provides a NA range of 0.85 to 1.35 and supports field sizes of 26x33 mm 2. The XT:1900i lens performance is shown in Figure 1. As can been seen, the Zernike RMS values are below 1nm (5 mλ) and the grouped Zernikes are below 0.5nm (2.5 mλ). (See Fig. 2) Complementing the Starlith 1900i lens is the AERIAL XP illuminator. This illuminator supports a wide range of continuously adjustable illumination settings in different polarization modes with improved pupil parameters such as ellipticity and telecentricity. For both polarized and un-polarized use, the system provides maximum efficiency for all supported illumination modes. With Diffractive Optical Elements (DOE) the partial coherence (σ) range for conventional illumination can be varied between 0.12 and 0.94, for annular illumination the minimum ring width is 0.12 with a maximum sigma value of 0.97, which relates to a geometrical sigma of 1.0. The HydroLith immersion technology of the XT:1900i is an evolution of the technology used in the XT:1700i. The fluid containment method is based on local containment under the lens using an immersion hood. In addition to water containment by the immersion hood, thermal control of the wafer is a key aspect of any immersion system. The two most important modules essential for good thermal control are the immersion hood and the wafer table. 8

9 ASML Images, Spring Edition 2007 XT:1700i XT:1900i NA Lens type Catadioptric Illuminator type Polarized Immersion liquid Water Scan speed (mm/s) wave front [nm] rms final adjustement lens model prediction every bar is one lens Z5-Z36 spherical coma astigmatism three-foil Aberration type Resolution (nm) CD Uniformity (3σ,nm) Figure 2: XT:1900i lens aberration performance. Dedicated Chuck overlay (99.7%, nm) 6 5 Single Machine Overlay (99.7%, nm) 7 6 Throughput (wafers/hour) Figure 1: System overview and main specifications. Overlay [nm, 99.7%] x y 1 In the immersion hood, the uniformity of the laminar water flow has been improved significantly and this results in improved refractive index homogeneity. The wafer table has been improved in two aspects: the spatial thermal control of the wafer and the stability over time. These design improvements yield excellent focus and overlay control. Another key indicator of immersion performance is defectivity. A separate article on page 10 cover this in detail. Imaging Resolution of 36.5 nm half pitch has been realized (See Fig. 5). This resolution corresponds to a k 1 value of that is very close to the theoretical limit of nm Day 1 Day 1 Day 1 Figure 3: Single Machine Overlay (including both wafer stages). Overlay [nm, 99.7%] x y A resolution of 36.5nm half pitch in resist is demonstrated with the NA=1.35 projection lens 0.0 nm Wafer Figure 4: Reversed Dedicated Chuck Overlay with a full lot performance of 2.6 and 2.7 nm in X and Y, respectively. Focus performance is measured by the leveling verification test (LVT). This test measures full wafer focus control. The uniform thermal wafer control results in full wafer focus control below 25nm. Another advantage of the stable thermal control is the insensitivity to different wafer exposure layouts, for example different field sizes. Overlay and defectivity Improved thermal control also leads to the impressive low-single-digit overlay performance as seen in Fig 3. Using the system in chuck dedication mode Overlay can be further improved to below 3nm. This performance makes the 1900i capable of double patterning, thus paving the way to resolutions of 32nm and below (See Fig. 4). demonstrating the capability of the 1.35NA lens. It also shows that the image contrast is very high and that contrast contributions like polarization, stray light and dynamics are well under control. With the illumination mode called C-quad, both orientations can be printed as is shown in the figure 6. The resulting overlapping depth of focus (DoF) is 300nm enabling a robust process window. With more than 40 immersion systems shipped, ASML continues to drive immersion lithography forward. Several customers are already using the TWINSCAN XT:1700i in production. Now, with the release of the first 36.5-nm dense line images, the XT:1900Gi provides the next step for 40-nm production. Figure 5: Resist picture of 36.5-nm 1:1 dense lines/spaces. 300nm -150nm -60nm +10nm +150nm Overlapping DoF Figure 6: Top down images of 38-nm horizontal and vertical lines and spaces. Exposed with C-quad illumination, NA= 1.35.

10 Immersion An approach to defect reduction By Jos Maas Abstract Over the last year, ASML has expanded its efforts to reduce defects in immersion lithography. We ve been working on both optimizing our systems and looking at real-life production processes to identify and solve the key issues. Thanks to these efforts, we are much better able to consistently deliver defect levels of < 10 per wafer at high scan speeds. In the Spring 2006 edition of Images, we told you about ASML s activities to reduce the defects in immersion lithography systems. At the time, we were focused on defects that arose from water droplets escaping from the immersion water within the scanner. Since then, we ve been looking at the immersion lithography process as a whole. Working with customers and track suppliers, we ve been investigating the types of defects that appear in actual immersion processes and developing ways to eliminate them. Types of defects There are two basic types of defect related to immersion processes those caused by droplets escaping the pool and those caused by particles. Of course, other defects not directly related to immersion lithography can also occur, for example bridges that are process-related defects also seen with dry systems. (See Fig. 1) Droplet-related defects include drying stains and water marks, while bubbles in the immersion water can lead to pattern attenuation. These defects have been extensively studied and are well understood. They can be controlled by design features within the scanner, such as the double fluid containment concept used in ASML s HydroLith immersion hood (IH). This unique IH design includes an air-gap actuator to maximize meniscus stability plus an air curtain that pushes any escaping droplets back into the main pool. Together, these features allow ASML immersion systems to operate at higher scan speeds. A particular problem Printed particles are by far the most common of the various classes of defects. In an immersion system, printed particles arise when the immersion pool washes debris from the edge of the wafer into the area to be processed. Extensive investigations into printed particles have been carried out, both at our own R&D facilities and jointly with customers. These investigations revealed that the debris is typically either flakes of material from the resist stack or contamination on the wafer edge that came from other process steps. Beyond the scanner If the resist or topcoat is not correctly bonded onto the stack, the impact of the immersion pool on the edge of the wafer can cause material to flake off. Specifically topcoats and resists tend not to bond well with silicon. Consequently, the edge bead removal (EBR) design of a resist stack is a vital factor in delivering consistently low defect levels. (See Fig. 2) Wafers with zero immersion-related defects have been readily achieved using an XT:1700i We have investigated a number of EBR strategies and an immersion optimized EBR design can significantly reduce the number of flakes. The best EBR strategies for immersion are those where both the resist and topcoat are on top of the backside anti-reflective coating (BARC). This gives the best adherence to the wafer. 10

11 ASML Images, Spring Edition 2007 Class Patern expansion Drying stains Inverted attenuation Pattern attenuation Printed particle Bridge Micro bridge Missing patern Examples Structure Size Circular or irregular μm Round deposists μm Circular shape narrower pitch μm Circular shape wider pitch μm Irregular; Particle affecting pattern μm Bridge between 2 lines < 0.5 μm Hair-like bridge between 2 lines < 0.2 μm Circular, resist is gone μm Root cause Droplet interaction with resist Droplet drying after resist leaching Partical or droplet swelling topcoat/ resist before exposure Bubble on topcoat/resist Particles exposed Resist process or small particle Incomplete develop rinse or small particle Solvent splash back in track Figure 1: Defects classes and root causes EBR-1 EBR-2 EBR-5 EBR-7 Immersion defects at 550 mm/s scan speed i BARC 0.5 mm BARC 0.5 mm BARC 0.5 mm BARC 0.5 mm 20 Topcoat 1.4 mm Topcoat 1.4 mm Topcoat 1.4 mm Resist 2,2 mm Resist 2,2 mm Resist 2,2 mm defects 50 defects 5000 defects 5000 defects Topcoat Edge peeling Resist HMDS Immersion defects [#] Mean Wafer XT:1700i, not linked to track BARC Wafer Figure 2: Patterned defect results for 4 different EBR strategies, wafer map represents result of 4 stacked wafers Figure 3: Through lot defect performance XT:1700i. Average < 3 defects per wafer. Keeping processes clean The other primary cause of printed particles is contamination on the edge of the wafer. Obviously, using clean wafers alleviates this problem, but in even the cleanest of cleanrooms, particles will occasionally be present on wafers as they reach the scanner. As well as potentially causing defects on that wafer, these particles can contaminate the immersion water leading to problems for subsequent wafers. In response, ASML has developed two mechanisms to reduce particle contamination. Our active bevel edge seal (BES), first introduced on the XT:1250i, removes particles from the bevel of the wafer, preventing them from contaminating the top side of the wafer. In addition, in-line Auto-Flush technology cleans the system during idle periods. Together, these mechanisms can reduce defect counts and the spread between wafers. Latest results Thanks to these investigations, ASML, our partners and our customers have developed a better understanding of immersion processes and immersion systems in production environments. Using this understanding, we ve been able to reduce the defect count and improve the consistency with which low defect counts are delivered (See Fig. 3). Average through lot defect performances of less than 3 per wafer, including wafers with zero immersion-related defects, have been readily achieved using an XT:1700i at our own facilities. In production set-ups, customers using the XT:1700i have realized average through lot defect performances of less than 5 total defects per wafer. These low defect levels are possible at scan speeds up to 550 mm/s, enabling maximum productivity and yield. 11

12 Smart Service enables best-in-class support by Fränk Zwaans Abstract Our Smart Service program is designed to maximize your profitability through efficient, proactive support. Through highly skilled 1 st line staff, remote diagnostic tools and three Global Support Centers, Smart Service offers a rapid response around the clock. You probably know ASML as the lithography technology leader. But we re about much more than just the machines. We aim to be a true partner to semiconductor manufacturers and deliver the best all-round value. That s why we re continually reviewing our system designs, parts quality and delivery methods. It s all part of our ongoing commitment to help you boost productivity through higher system availability. Global Support Centers Key to the reorganization are our new Global Support Centers (GSCs) in Linkou (Taiwan), Tempe (USA) and Veldhoven (Netherlands). These three GSCs house ASML s expert support staff, concentrating our expertise into convenient central locations. And through the follow the sun model you can always access this critical resource 24 hours a day, 7 days a week. Eliminate the downtime spent waiting for the required technical expertise to arrive at your site One aspect of that commitment is a dedication to high-quality customer support. Our new Smart Service program is the perfect example. It aims to improve support and maximize your productive time through efficient use of resources, 24/7 coverage and smart scheduling of maintenance. To make this pledge a reality, ASML is restructuring our support organization and furthering the use of remote diagnostic tools. These changes help us reduce the time it takes to diagnose problems and ensure the right skills and knowledge are always available to solve them as quickly as possible. The end result is faster service leading to more productive time for your lithography cluster. In addition to establishing the GSCs, we re also reviewing the skill set and knowledge base of our frontline support staff. By focusing their training on the incidents that cause most stoppages, we ensure that the majority of issues can be solved on site. Remote diagnosis Through remote diagnostics and support (RDaS) tools such as Prime Time, our experts can assess and solve issues with your machines from the GSC. This greatly reduces and could perhaps even eliminate travel time for technical support staff, enabling much faster customer service. We ve already carried out RDaS pilot schemes. The results were overwhelmingly positive more than 90% of incidents could be handled remotely. In some cases, the RDaS tools even allowed our experts to monitor the status of ageing components and arrange for 12

13 ASML Images, Spring Edition 2007 replacements to be carried out during the next scheduled maintenance, thereby preventing costly failures and unplanned downtime. Maximizing productivity RDaS tools and the reorganization of our support staff are designed to eliminate the downtime spent waiting for the required technical expertise to arrive at your site. Thanks to these tools and our targeted training programs, our on-site staff are now better prepared than ever to handle more incidents so fewer calls need to be escalated. And when more specialist knowledge is required, it is available remotely 24 hours a day, 7 days a week. 13

14 XT:1400 shipments top 100 by Rard de Leeuw and Stuart Young Abstract With over 120 systems shipped, the XT:1400 is the industry s highest-volume ArF tool. It has proven successful in all market segments thanks to its established technology and unrivalled blend of performance, productivity and flexibility. Due for release in the second half of this year, the next-generation XT:1450G extends the system s resolution capability down to 57 nm. In January this year, the 100 th TWINSCAN XT:1400 system was shipped. By the end of the first quarter, that number had risen above 120 making the XT:1400 by far the highest-volume ArF tool in the industry. Suited to all market segments, the system offers excellent imaging and overlay performance. What s more, the F version of the XT:1400 regularly achieves production averages above 3000 good-wafers per day, helping make it the ArF tool of choice for the vast majority of manufacturers. That maturity leads to very stable systems with potential issues like contamination and optics degradation already solved before the XT:1400 was released. In addition, it allows The extendibility to continue meeting new technology nodes Building on strong foundations The XT:1400 is ASML s 7 th generation ArF system. Building on the firm foundations of the six previous ArF generations, it leverages the mature and proven technology of the TWINSCAN platform. manufacturers to re-use any process enhancements previously developed for TWINSCAN KrF production tools. The modular TWINSCAN platform also offers customers a great deal of 14

15 ASML Images, Spring Edition 2007 XT:1400 SMO spec=6nm XT:1400 MMO spec=14nm -210nm 0nm +210nm XT:1400 SMO XT:1400 MMO XT:1400 MMO KrF Figure 1: 57nm lines 114nm pitch, NA/sigma 0.93/0.97/0.813, cquad20, XY polarised, 6% attpsm Figure 2: 44nm lines 88nm pitch, NA/sigma = 0.93/0.5. Figure 3: XT:1400 single machine overlay (SMO) performance, XT:1400 matched to XT:1400 (MMO) XT:1400 matched to XT:8x0 (MMO KrF) Expected XT:1450 distribution is also shown. flexibility. As well as enabling systems to be tailored to specific needs, it allows customers to select and purchase additional functionality and upgrade systems as their needs evolve. Moreover, when new systems are released, many of the enhancements and options can be fitted to existing systems in the field, providing customers with the extendibility to continue meeting new technology nodes with their current installed base. The next generation In the second half of 2007, we will release the next generation of our TWINSCAN ArF family. The XT:1450G will be available with a new option called the AERIAL-P high-transmission illuminator, which provides polarized light at production XT:1400F XT:1450G XT:1450G AERIAL-P NA Resolution 65 nm 65 nm 57 nm CDU@BF (L/S) 4 nm 4 nm 4 nm Laser power 45 W 45 W 45 W Double patterning overlay 4 nm 4 nm Single Machine Overlay (SMO) 8 nm 6 nm 6 nm Matched Machine Overlay (MMO) 14 nm 10 nm 10 nm Throughput 133 wph 143 wph 143 wph Specifications throughput levels. AERIAL-P can also be fitted to XT:1400F systems that were shipped from Q onwards. With the AERIAL-P illuminator fitted, the XT:1450G extends the resolution of the XT:1400 series down to 57 nm while increasing throughput and improving overlay. In addition, it supports double patterning development with < 4-nm overlay, enabling process research for 30-nm applications. 15

16 Innovative partnership offers benefits for all by Richard Visser Abstract ASML has established an innovative partnership with Philips MiPlaza. The agreement gives MiPlaza and its customers access to a PAS 5500/100D stepper an invaluable and unique development resource. Using the stepper, MiPlaza customer Cytocentrics recently developed a successful double-sided process, providing real-world verification of ASML s 3DAlign option for backside alignment. Good partnerships offer benefits to all the parties involved and beyond. That is the guiding principle behind the relationship between ASML and MiPlaza Philips open innovation center for industrial research into microsystems. The relationship dates back to October 2006, and developed from ASML s cooperation with the Holst Centre, an independent More-than-Moore research center created by the Belgian R&D institute IMEC and the Netherlands Organization for Applied Scientific Research (TNO). As part of the arrangement, ASML provided the MiPlaza Thin Film Facilities department with a fully equipped PAS 5500/100D i-line stepper. Applications group. For example, ASML may supply new technologies or system modules to address a customer s particular process need. If that need is sufficiently widespread, we can then offer the technology to other customers. Unique industrial research resource The PAS 5500/100D stepper is housed in MiPlaza s multi-purpose cleanroom for thin-film device fabrication at the High Tech Campus Eindhoven. It can be used by MiPlaza as a shared service to its customers as well as the Holst Centre for research, product development and pre-production. The agreement also gives ASML access to the tool and other MiPlaza facilities for testing and demonstration purposes. In addition to supplying the stepper, ASML also offers MiPlaza s customers expert support through our Special We operate in the world of open innovation, providing industrial research services for external companies as 16

17 ASML Images, Spring Edition 2007 worked first time. This combination also enables back-side alignment with ten times higher accuracy than the best alternative technique. Since that first success, Cytocentrics has gone on to achieve successful double-sided processing on thinned (400 µm and 300 µm) wafers. These thin well as Philips, explains Frank Dirne, wafers are used for so-called throughhole processes often found in MEMS head of the MiPlaza Thin Film Facilities department. With the addition of the manufacturing. PAS 5500 stepper, we can now offer our customers a complete range of For Cytocentrics, this application lithography solutions from a contact is just one of the benefits of having aligner through reduction lithography access to the MiPlaza stepper. We to e-beam. The stepper also lets our focus on smaller projects and start-up customers run at pre-production companies, so the scale is too small throughput levels for faster process to interest foundries but too large for tuning. That s invaluable for industrial universities, Peter adds. The MiPlaza research, and unique to MiPlaza. facilities and the ASML stepper provide Back-side alignment with ten times higher accuracy than the best alternative technique First-time back-side align success a production-like environment that helps One of the companies taking advantage us get to market faster. That gives us a of MiPlaza s unique facilities is competitive advantage and offers big Cytocentrics, who use the cleanroom benefits for our customers. facilities to develop and produce microsystem products for a number A win-win situation of external customers. A MiPlaza ASML s relationship with MiPlaza is a customer for 3 years, Cytocentrics winner for everyone. It gives MiPlaza recently became the first company cost-effective access to an advanced, to successfully integrate back-side production-level tool that is vital for the alignment using the PAS 5500/100D and center s industrial research. MiPlaza s ASML s 3DAlign option. customers gain access to this tool and to ASML support, allowing them to Double-sided processing is becoming deliver innovative new products faster. increasingly necessary in numerous applications, says Peter van Stiphout, For ASML, it offers the perfect Director of Cytocentrics BV. We opportunity to prove the value of needed to investigate it for a product innovations like 3DAlign in real-life we re developing for a customer. Using settings. And that allows us to offer new the 3DAlign option on the PAS 5500 options to our wider customer base stepper we created a process which earlier and with guaranteed reliability. MiPlaza enabling open innovation MiPlaza (Microsystems Plaza) offers world-class expertise, service and infrastructure, enabling you to carry out high-tech research in the most efficient way. In a world of increasing technological complexity, MiPlaza provides fast and cost-effective access to the advanced technology and know-how that will help you accelerate your pace of innovation. Located at the High Tech Campus Eindhoven, the Netherlands, MiPlaza operates in an Open Innovation environment, working with high-tech global companies, start-ups, research institutes and entrepreneurs in a networked ecosystem, forming a cradle of innovation and business creation. Cytocentrics the microsystems technology center Cytocentrics BV was founded in January 2005 as a full subsidiary of Cytocentrics AG. In addition to developing and producing key microsystem products for its parent company, Cytocentrics BV has evolved into a leading microsystems technology service provider offering smart solutions that combine consultancy and state-of-the-art technology with expertise and experience. The company specializes in translating customers ideas into tailor-made thinfilm designs with the focus on quality, feasibility and production costs. Its products are mainly used in the life sciences and pharmaceutical industry, where product miniaturization is required for drug discovery, diagnostics and therapeutics, but is also active in other market segments. 17

18 Reticle availability increasing good-wafers per day by Jan-Evert van de Wetering Abstract Semiconductor manufacturers are continually striving to increase yield through more good-wafers per day. ASML supports this drive through an ongoing program of solutions to boost reticle availability. With our latest options, 3000 plus good-wafers per day is well within reach. What s more our reticle availability roadmap supports even higher numbers of good-wafers per day in conjunction with ultra-high throughputs. Our latest G specification TWINSCAN systems offer throughputs up to 150 wafers per hour or more. At these high wafer processing rates, the time taken to set up for a new lot can significantly impact a cluster s overall output of good wafers per day. A major factor in the lot set up time is reticle availability. And with throughputs set to increase to extreme values, reticle availability will continue to grow in importance. Complementing our throughput and system availability roadmaps, ASML has an ongoing roadmap for reticle availability solutions. These solutions are designed to support the drive for more good-wafers per day while reducing automation costs and the number of operators required per tool. Thanks to the TWINSCAN platform s modular architecture, each new reticle availability enhancement can be fitted to existing systems maximizing your total Value of Ownership. Keeping things clean Our Integrated Reticle Inspection System (IRIS) is the industry s only solution for checking the condition of a reticle in situ. It allows you to schedule reticle cleaning only when it is needed rather than based on conservative estimates, thereby reducing downtime and costs without negatively impacting product quality. The latest version, the recently released IRIS-XT, is capable of detecting particles from 5 to 1000 µm. That enables it to spot everything from a human hair to reticle haze crystals a particular problem for ArF lithography. Extremely fast, IRIS-XT can scan both sides of a wafer in just 90 seconds. That means you can scan up to 12 reticles an hour without affecting productivity. Intelligent reticle handling While IRIS-XT improves productivity and yield by monitoring the condition of your reticles, our Reticle Streaming package aims to reduce the overhead time for each lot through intelligent reticle handling. By introducing smart parallel processing wherever possible, Reticle Streaming reduces the number of reticle handling tasks and schedules them in an efficient sequence. For example, it communicates with IRIS to arrange reticle scans for periods when the system is otherwise idle. It also offers a user-configurable 1 st wafer delay timer to compensate for delayed wafer delivery from the track. Through these and other features, Reticle Streaming can reduce the minimum theoretical wafer exchange time by 2 seconds, from today s current best of 13 seconds to 11 seconds and even better on some systems. In addition, it helps reduce the number of exceptional events where the time between lots is significantly longer than the minimum (See Fig. 1). 18

19 ASML Images, Spring Edition Reticle libraries and beating the haze Rising system throughput means the time taken to process each lot is falling. In fact, it is becoming increasingly difficult for operators to manually load reticles for each lot. Already reticle loading can impact good wafer per day outputs by around 2% on current installed base systems Lot number Figure 1: Opportunity to reduce lot overhead with Reticle Streaming Series 1 Wait for IRIS scanning, other exceptions 1st wafer from track delay Streaming NOK Theoretical minimum: reticle exchange time 13 seconds Streaming OK operators to pre-load a number of reticles at once. As each new lot reaches the tool, the appropriate inspected reticle can be quickly loaded from the library. and helps minimize the production time lost for reticle cleaning. An ongoing effort Altogether, this current generation of reticle availability solutions reduces lot overheads by up to 6%, enables 30% faster reticle inspections, decreases reticle exchange times by around 25% and extends ArF reticle cleaning periods by 50%. That places outputs of 3000 good-wafers per day within easy reach. However, manufacturers wafer-per-day roadmaps stretch to extreme numbers and outputs of 4000 good-wafers per day are already being mentioned for the near future. To support these roadmaps, we are continuing to investigate new reticle availability solutions such as in situ reticle top-side cleaning and larger Reticle Streaming can reduce the minimum theoretical wafer exchange time by 2 seconds This is leading to a move away from traditional reticle streaming through load ports. Instead, reticles are starting to be streamed from libraries internal reticle storage facilities within each lithography tool. The load ports are then only used to fill or update the library and for exception handling. A few years ago, ASML introduced the Integrated Reticle Library (IRL) for our TWINSCAN platform. It allows Due for release later this year, IRL-XP takes internal reticle storage one step further. The reticle library is XCDA (extra clean dry air) purged, to ensure the reticles stay clean and dry. Water and residual chemicals, along with 193-nm light, are key ingredients in the formation of reticle haze. By keeping the reticles dry, IRL-XP reduces the build up of this haze internal reticle libraries. The overall goal of this program is to enable our customers to maximize their wafer-per-day output without worrying about clean, available reticles. 19

20 An introduction to photolithography Imaging by Rian Rubingh Abstract In the second of our introduction to photolithography articles we take a look at imaging a lithography system s ability to consistently print the ever smaller features that keep the semiconductor industry moving forward. 20

21 ASML Images, Spring Edition 2007 The drive for more performance, functionality and cost efficiency in the semiconductor industry is intimately linked to the ability to print smaller and smaller IC features. That ability is governed by the imaging performance of the photolithography systems used. A lithography system s imaging performance is essentially determined by two key specifications: resolution (or critical dimension) and critical dimension uniformity (CDU). Resolution is the smallest feature size the system can print, while CDU is a measure of the spread in that smallest image size. System resolution (CD) is determined by the Rayleigh equation: CD= k 1 λ NA where λ is the wavelength of the light used, NA is the numerical aperture of the system s lens and k 1 is known as the resolution factor and accounts for all other process variables. Improving resolution then comes down to using shorter wavelengths of light, increasing the numerical aperture and / or reducing k 1. Shorter wavelengths As mentioned in the last issue, photolithography has progressed in a series of wavelength jumps. This has taken the industry from the violet 436-nm g-line of a mercury vapor lamp in the early eighties, through 365-nm i-line and 248- nm KrF (krypton-fluoride) to today s deep ultraviolet (DUV) 193-nm light from an ArF (argon-fluoride) laser. Each step has brought significant advances in resolution, with systems like the our XT:1400F (the ArF tool of choice for the vast majority of manufacturers) capable of resolving features of 65 nm. Looking towards the next wavelength jump, many customers have extreme ultraviolet (EUV) lithography on their production roadmaps. Research institutes are already involved in process R&D using 13.5-nm EUV systems and the most recent research data has shown the technology s capability with 32-nm features. (For more about recent EUV developments, see page 6). Lens technology Switching wavelengths presents numerous technical challenges that often require significant investment in time and engineering resources to resolve. For example, different wavelengths need new sources (e.g lasers), resists and optics. So relying solely on wavelength jumps to improve resolution would slow down development due to the costs and technical challenges involved. However, continuous improvement in lens technology helps keep the industry Our systems offer industry leading imaging performance moving forward by increasing the numerical aperture (NA). For example, in the mid 80s an NA of 0.4 was typical. Today, our XT:1400 systems offer a variable NA up to Refractive index and immersion lithographymathematically speaking, NA= n sin α where n is the refractive index of the medium surrounding the lens and / is the lens s acceptance angle. So for a lens in air, NA has a theoretical maximum of 1 although in practice this is limited to 0.93 a value achieved by our latest dry lithography systems. However, immersing the lens in a medium with a higher refractive index gives the possibility of NA > 1 and hence better resolution this is the basis of immersion lithography. Currently water (with a refractive index of 1.43) is used as the immersion fluid because it has the best transmission and chemical properties. However, researchers are also looking at potential immersion fluids with even higher refractive indices. Immersion ArF lithography is now being deployed in cutting-edge wafer production. With NA = 1.35, our XT:1900i immersion ArF system has the largest NA of any system currently available and offers resolutions of 40 nm and beyond. (See page 11 for the first images from the XT:1900Gi.) Lens quality and CDU While the lens s numerical aperture plays a key role in determining the system s resolution capabilities, lens quality plays a key role in determining the CDU performance of a system as do other factors such as illumination uniformity and reticle quality. Together with our partner Carl Zeiss, ASML is continually striving to improve the quality of both immersion and non-immersion (dry) lenses by driving down aberration levels. Thanks to these efforts, our systems offer best-in-class CDU performance. For example, the XT:1450G dry ArF tool has a CDU of 4 nm (at 65 nm resolution) and the XT:1900Gi has a CDU of 2 nm (at a resolution of 5 nm). Resolution factor The final part in Rayleigh s equation is the resolution factor k 1, which relates to the difficulty of the imaging process. It depends on several process variables such as the quality of the resist and the use of resolution enhancement techniques like off-axis illumination. The resolution factor k 1 has a theoretical minimum value of 0.25 *, however values below 0.3 are considered difficult or expensive to achieve. ASML works closely with our customers to reduce k 1 to extend the capabilities and usage of current lithography technologies and ASML systems. Our Ultra-k1 portfolio of hardware, software and mask solutions 21