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Extreme ultraviolet (EUV) lithography is expected to succeed in 193-nm immersion multi-patterning technology for sub-10-nm critical layer patterning. In order to be successful, EUV lithography has to demonstrate that it can satisfy the industry requirements in the following critical areas: power, dose stability, etendue, spectral content, and lifetime. Currently, development of second-generation laser-produced plasma (LPP) light sources for the ASML’s NXE:3300B EUV scanner is complete, and first units are installed and operational at chipmaker customers. We describe different aspects and performance characteristics of the sources, dose stability results, power scaling, and availability data for EUV sources and also report new development results.

In this paper, we provide an overview of various challenges and their solutions for scaling laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source performance to enable high volume manufacturing. We will discuss improvements to source architecture that facilitated the increase of EUV power from 100W to >200W, and the technical challenges for power scaling of key source parameters and subsystems. Finally, we will describe current power-scaling research activities and provide a forward looking perspective for LPP EUV sources towards 500W.

We present highlights from plasma simulations performed in collaboration with Lawrence Livermore National Labs. This modeling is performed to advance the rate of learning about optimal EUV generation for laser produced plasmas and to provide insights where experimental results are not currently available. The goal is to identify key physical processes necessary for an accurate and predictive model capable of simulating a wide range of conditions. This modeling will help to drive source performance scaling in support of the EUV Lithography roadmap. The model simulates pre-pulse laser interaction with the tin droplet and follows the droplet expansion into the main pulse target zone. Next, the interaction of the expanded droplet with the main laser pulse is simulated. We demonstrate the predictive nature of the code and provide comparison with experimental results.

BACKGROUND: South Africa has the greatest burden of HIV-infection in the world with about 5.2 million HIV-infected adults. In 2003, the South African Government launched a comprehensive HIV and AIDS care treatment program supported by the United States in 2004 through the President's Emergency Plan for AIDS Relief (PEPFAR). METHODS: To describe the scale-up and continuation of antiretroviral therapy in South African Government and PEPFAR-supported sites in South Africa, we conducted a retrospective analysis of routinely collected program reporting data, 2005-2009. RESULTS: From 2005 through 2009, the average rate of persons initiated on antiretroviral therapy in PEPFAR-supported South African Government treatment programs increased nearly four-fold from 6,327 a month in 2005-2006 to 24,622 a month in 2008-2009 resulting in an increase from 33,543 patients on continued treatment in April-June 2005 to 631,985 patients in July-September 2009. Of those 631,985 patients receiving treatment, 65% were women. Men were more likely to be lost to follow-up (9.2% vs. 7.8%, PR 1.18, 95% CI 1.17-1.19) and more likely to die (5.6% vs. 4.1%, PR 1.36, 95% CI 1.35-1.37) than women. CONCLUSIONS: Scale-up and continuation of antiretroviral therapy in South Africa has been a remarkable medical accomplishment. Because more women receive and continue treatment, more efforts are needed to treat and retain men.

Moore's Law, which predicts thecontinued increase in device density onintegrated circuits, has been driven by advancesin lithography. Both resolutionand productivity of the exposure toolhave been enabled by the light sourcetechnology. The transition to shorterwavelength, first by introducing excimerlasers and more recently by developmentof EUV Laser Produced Plasma sources hasdriven resolution. In addition, the continuedcost effectiveness of lithography isdependent on the scaling of the power output for both types of source.

During the mid 18th century, the standard British Army issue weapon was the Brown Bess Musket. There are various accounts of the performance of this early form of firearm and its tactical deployment (e.g. Hanger 1816). Using a technical replica of the Brown Bess, range trials and computer modelling have been used to asses the weapon's capabilities and likely performance. The research found the Brown Bess musket to be a lethal weapon at the ranges at which enemy was commonly engaged, so long as it was accurate enough to hit the target. A single shot fired at 150 yards could penetrate at least two soldiers, even if bone were hit. The armour of the day (shields of wood, leather and sometimes steel, and the layers of woollen clothing) was easily pierced by the shot. The shot was found to readily deform on impact with metal targets. The maximum range could extend to around 1200m, with 202m reached when fired horizontally.

This paper describes the development and evolution of the critical architecture for a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing (HVM). In this paper we discuss the most recent results from high power sources in the field and testing on our laboratory based development systems, and describe the requirements and technical challenges related to successful implementation of those technologies on production sources. System performance is shown, focusing on pre-pulse operation with high conversion efficiency (CE) and with dose control to ensure high die yield. Finally, experimental results evaluating technologies for generating stable EUV power output for a high volume manufacturing (HVM) LPP source will be reviewed.

Multiple NXE:3300 are operational at customer sites. These systems, equipped with a Numerical Aperture (NA) of 0.33, are being used by semiconductor manufacturers to support device development. Full Wafer Critical Dimension Uniformity (CDU) of 1.0 nm for 16nm dense lines and 1.1 nm for 20nm isolated space and stable matched overlay performance with ArF immersion scanner of less than 4nm provide the required lithographic performance for these device development activities. Steady progresses in source power have been achieved in the last 12 months, with 100Watts (W) EUV power capability demonstrated on multiple machines. Power levels up to 90W have been achieved on a customer machine, while 110W capability has been demonstrated in the ASML factory. Most NXE:3300 installed at customers have demonstrated the capability to expose 500 wafers per day, and one field system upgraded to the 80W configuration has proven capable of exposing 1,000 wafers per day. Scanner defectivity keeps being reduced by a 10x factor each year, while the first exposures obtained with full size EUV pellicles show no appreciable difference in CDU when compared to exposures done without pellicle. The 4th generation EUV system, the NXE: 3350, is being qualified in the ASML factory.

Since their invention in 1966 copper vapour lasers (CVLs) have developed into a mature technology with applications including high-speed imaging, micro-machining, non-linear frequency conversion to the ultraviolet, and pumping of solid-state laser materials. However, the performance characteristics of conventional CVLs are fundamentally limited by kinetic processes at play within the gain medium and hence, these devices largely failed to keep pace with advances in visible solid state lasers during the late 1980s and early 1990s. In 1996 a new subclass of CVL, termed a kinetically enhanced or KE-CVL, was developed that used a ternary gas mixture (HCl–H2–Ne) to tailor the kinetic processes that limit laser performance. These devices offer dramatic improvements in power (both average and high beam quality) and repetition rate scalability. Indeed, 100 W of visible, high beam quality power is now readily available from relatively small copper laser systems. In this paper the underlying principles and performance characteristics of KE-CVLs will be reviewed.

This paper describes the development of a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193nm immersion double patterning technology for sub- 20nm critical layer patterning. In this paper we discuss the most recent results from high power testing on our development systems targeted at the 250W configuration, and describe the requirements and technical challenges related to successful implementation of these technologies. Subsystem performance will be shown including Conversion Efficiency (CE), dose control, collector protection and out-of-band (OOB) radiation measurements. This presentation reviews the experimental results obtained on systems with a focus on the topics most critical for a 250W HVM LPP source.

Laser produced plasma (LPP) light sources have been developed as the primary approach for EUV scanner imaging of circuit features in sub-20nm devices in high volume manufacturing (HVM). This paper provides a review of development progress and readiness status for the LPP extreme-ultra-violet (EUV) source. We present the latest performance results from second generation sources, including Prepulse operation for high power, collector protection for long lifetime and low cost of ownership, and dose stability for high yield. Increased EUV power is provided by a more powerful drive laser and the use of Prepulse operation for higher conversion efficiciency. Advanced automation and controls have been developed to provide the power and energy stability performance required during production fab operation. We will also discuss lifetesting of the collector in Prepulse mode and show the ability of the debris mitigation systems to keep the collector multi-layer coating free from damage and maintain high reflectivity.

We report the performance characteristics of a copper laser master-oscillator power-amplifier system incorporating kinetically enhanced active elements. The advantages provided by kinetic enhancement lead to record brightness levels.

We report dramatic improvements (up to four times) in the generation of high-beam-quality (HBQ) output power from copper vapor lasers (CVLs) by using tailored HCl-H/sub 2/-Ne buffer gas mixtures. Up to 60 W of HBQ power was obtained from a 38-mm bore-diameter CVL at a pulse repetition frequency of 12 kHz and 50 W at 22 kHz. This improvement in power capability is attributable to the modification of the spatio-temporal gain characteristics of the laser when using the new buffer gas mixture.

Etch rates (/spl mu/m/pulse) for glycol-modified polyethylene terephthalate (PETG) under pulsed UV (255 nm) laser processing are measured as a function of pulse repetition frequency in the range 0.7-15 kHz. Materials removal rates (/spl mu/m/s) scale approximately linearly with pulse repetition frequency at a fluence of 0.59 J/cm/sup 2/, and there appears to be no attenuation of the ablating laser beam by the ejected material plume for pulse rates up to 15 kHz. The instantaneous etch rate for pulses in a sequence increases markedly (/spl sim/40%) for long pulse sequences (>100 pulses) at high PRF (15 kHz), an effect which can be used to increase machining rates while operating at a moderate laser fluence.

We report on the operation of a 6 cm bore copper HyBrID laser which incorporates a high-magnification (M = 280) negative-branch confocal optical resonator and utilizes a magnetic pulse compression excitation circuit. 125 W total output was obtained at a pulse repetition frequency of 12.5 kHz, of which 101 W (i.e. 80% of the total) was high beam quality output. `Power in the bucket' measurements revealed that of the high beam quality output was within the diffraction limit (62 rad), and within the diffraction limit.

The output powers from 25 mm (volume 0.49 l) and 40 mm (volume 1.9 l) diameter copper vapour lasers (nominally 20 and 55 W devices) are approximately doubled to >50 and >100 W respectively by adding small partial pressures of both H2 and HCl to the neon buffer gas. Our studies show that this gas mixture performs better than a H2–HBr admix, a result we attribute to more efficient reassociation of HCl in the plasma region.

We have studied the factors limiting the performance of a barium vapour laser (BVL) as the pulse repetition frequency (PRF) is elevated. By measuring the population densities of key barium species, we have found that increasing the PRF leads to progressively larger depletion of the axial pre-pulse Ba ground-state density (up to 85% at 15 kHz PRF), due to the combined effects of ion pumping and gas heating. A direct consequence of this Ba density depletion is a proportional decrease in the peak upper laser-level density of the 1.50 μm and 1.13 μm laser transitions (i.e. Ba 1 P 1 ) during the excitation pulse. The results suggest that ground-state depletion is the dominant factor limiting laser output at high PRFs, and that the effects of the pre-pulse lower laser-level and electron densities play a secondary role. The implications to the PRF scaling of BVLs and other metal vapour lasers are discussed.

Observations of amplitude modulation in laser pulses emitted by a discharge-excited Sr + recombination laser are presented. The mechanism of mode-beating is proposed to account for such behaviour. Comparisons are made with previous reports of similar behaviour in a number of metal vapour laser systems, and suggestions that this phenomenon is the result of self mode-locking are examined.

We report an injection-seeded oscillator system based on Cu HyBrID laser active elements producing 120 W of output power with pulse-average divergence

We report on a detailed study of the effects of bromine and hydrogen bromide buffer-gas additive on the electrical and lasing characteristics of a conventional, high-temperature copper vapour laser. At standard buffer gas flow rates HBrNe mixtures produced relatively small improvements in output power, however, larger increases in output power were observed at elevated HBrNe flow rates. Added HBr also significantly modifies the spatio-temporal characteristics of laser output, increasing the pulse duration by a factor of 2 while also improving the radial intensity profile. This result has important implications for improving the extraction of high beam quality output from devices employing high magnification unstable resonators.

Background The prevalence of hypertension is rising worldwide with an estimated one billion people now affected globally and is of near epidemic proportions in many parts of South Asia. Recent turmoil has until recently precluded estimates in Afghanistan so we sought, therefore, to establish both prevalence predictors in our population. Methods We conducted a cross-sectional study of adults ≥40 years of age in Kabul from December 2011-March 2012 using a multistage sampling method. Additional data on socioeconomic and lifestyle factors were collected as well as an estimate of glycaemic control. Bivariate and multivariable analyses were undertaken to explore the association between hypertension and potential predictors. Results A total of 1183 adults (men 396, women 787) of ≥ 40years of age were assessed. The prevalence of hypertension was 46.2% (95% CI 43.5 – 49.3). Independent predictors of hypertension were found to be: age ≥50 (OR = 3.86, 95% CI: 2.86 – 5.21); illiteracy (OR = 1.90, 1.05 – 1.90); the consumption of rice >3 times per week (OR = 1.43, 1.07 – 1.91); family history of diabetes (OR = 2.20, 1.30 – 3.75); central obesity (OR = 1.67, 1.23 – 2.27); BMI ≥ 30 Kg/meter squared (OR = 2.08, 1.50 – 2.89). The consumption of chicken and fruit more than three times per week were protective with ORs respectively of 0.73 (0.55-0.97) and 0.64 (0.47 – 0.86). Conclusions Hypertension is a major public health problem in Afghan adults. We have identified a number of predictors which have potential for guiding interventions.

Laser produced plasma (LPP) systems have been developed as the primary approach for use in EUV scanner light sources for optical imaging of circuit features at 20nm nodes and beyond. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from ASML. We present the latest results on power generation and collector protection for sources in the field operating at 10W nominal power and in San Diego operating in MOPA (Master Oscillator Power Amplifier) Prepulse mode at higher powers. Semiconductor industry standards for reliability and source availability data are provided. In these proceedings we show results demonstrating validation of MOPA Prepulse operation at high dose-controlled power: 40 W average power with closed-loop active dose control meeting the requirement for dose stability, 55 W average power with closed-loop active dose control, and early collector protection tests to 4 billion pulses without loss of reflectivity.

This paper describes the development of a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193nm immersion double patterning technology for sub-20nm critical layer patterning. In this paper we discuss the most recent results from high power testing on our development systems in San Diego, and describe the requirements and technical challenges related to successful implementation of these technologies. Subsystem performance will be shown including the CO2 drive laser, droplet generation, laser-to-droplet targeting control, intermediate-focus (IF) metrology, out-of-band (OOB) radiation measurements and system use and experience. In addition, a multitude of smaller lab-scale experimental systems have also been constructed and tested..

Laser produced plasma (LPP) systems are the leading approach for extreme-ultra-violet (EUV) lithography of circuit features at sub-20nm nodes. This paper reviews technology and development progress for high-power sources optimized for EUV lithography. Article not available.

We present results of a detailed study comparing the effects of H/sub 2/ buffer gas additive on the output power and the spatio-temporal evolution of laser output produced by copper vapor lasers of varying aperture-size. We show that while the optimum H/sub 2/ concentration is relatively insensitive to the laser diameter, it is influenced by the type of resonator employed and the total neon buffer gas pressure.

We report results of a detailed study investigating the effects of hydrogen additive on the generation of high-beam quality output from a copper vapor laser. Increases up to 390% were observed for the power extracted in the high-beam quality component of laser output, however, the power of the low beam quality output remained relatively unchanged. We attribute these results to modification of the spatio-temporal characteristics of the laser gain with added H/sub 2/. >

We report significant improvements in ultraviolet (UV) power generation at elevated pulse-repetition frequencies (10/spl ges/kHz) from a frequency-doubled copper-vapor laser (CVL), employing a Ne-H/sub 2/ buffer gas. In particular, UV powers of 1.3 W and 0.6 W at 255 nm (SHG green) were generated at 10 kHz and 20 kHz, respectively, when using H/sub 2/ additive in a medium scale (nominally 20 W) CVL oscillator. These results represent improvements of 6.5/spl times/ and /spl sim/100/spl times/, respectively, over the UV powers obtained for pure neon-buffer gas. The enhanced UV powers are directly related to the improvement in high-beam quality extraction from the CVL due to the beneficial effects of the H/sub 2/ add-gas on CVL gain characteristics. >

Progress in high average power UV generation by nonlinear frequency conversion of the output of copper-vapor lasers (CVL's) is reviewed. The specific parameters controlling the efficiency of nonlinear frequency conversion using CVL's are highlighted, with CVL beam quality and matching the optical beam delivery system to the characteristics of the nonlinear crystal being identified as the most significant issues. Recent experimental studies of second harmonic generation (SHG) with single-CVL oscillators and CVL oscillator-amplifier systems show that by careful optimization of the CVL pump laser and beam delivery systems, it is now possible to generate multiwatt average powers in the UV with high optical conversion efficiency (up to 35%) and overall electrical efficiency (approaching 0.1%). >

Through a number of experimental studies carried out on various experimental test stands we are characterizing the scaling of EUV power and collector lifetime. The current performance of the first generation of EUV sources to support EUV lithography scanners is at 20 W power and 70% availability. CO2 drive laser power of up to 17 kW has been reached, while average EUV power of nearly 50 W was demonstrated on an HVM I source with a laser pre-pulse at our facilities. The burst EUV power on this source was in excess of 90 W at 10% to 20% duty cycle and closer to 60 W at 80% duty cycle since the full set of automated controls has not yet been implemented on this source. Once the automation of the laser-droplet position controls is implemented on our pre-pulse system, the average source power is expected to reach power levels on the order of 100 W. Further scaling of source power through operation at repetition rates higher than 50 kHz was also shown to be possible. Through improved gas management, better coatings and parallel testing of collector samples, we have significantly extended the useful life of the source collector mirrors.

Laser produced plasma (LPP) systems have been developed as the primary approach for the EUV scanner light source for optical imaging of circuit features at sub-22nm and beyond nodes on the ITRS roadmap. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from leading scanner manufacturers. We present the latest results on exposure power generation, collection, and clean transmission of EUV through the intermediate focus. Semiconductor industry standards for reliability and source availability data are provided. We report on measurements taken using a 5sr normal incidence collector on a production system. The lifetime of the collector mirror is a critical parameter in the development of extreme ultra-violet LPP lithography sources. Deposition of target material as well as sputtering or implantation of incident particles can reduce the reflectivity of the mirror coating during exposure. Debris mitigation techniques are used to inhibit damage from occuring, the protection results of these techniques will be shown over multi-100's of hours.

Background South Africa has an estimated 1.5 million persons in need of antiretroviral therapy (ART). In 2004, the South African government began collaborating with the United States President's Emergency Plan for AIDS Relief (PEPFAR) to increase access to ART. We determined how PEPFAR treatment support changed from 2005-2009. Methods In order to describe the change in number and type of PEPFAR-supported ART facilities, we analyzed routinely collected program-monitoring data from 2005-2009. The collected data included the number, type and province of facilities as well as the number of patients receiving ART at each facility. Results The number of PEPFAR-supported facilities providing ART increased from 184 facilities in 2005 to 1,469 facilities in 2009. From 2005-2009 the number of PEPFAR-supported government facilities increased 10.1 fold from 54 to 546 while the number of PEPFAR-supported NGO facilities (including general practitioner and NGO facilities) increased 6.2 fold from 114 to 708. In 2009 the total number of persons treated at PEPFAR-supported NGO facilities was 43,577 versus 501,089 persons at PEPFAR-supported government facilities. Overall, the median number of patients receiving ART per site increased from 81 in 2005 to 136 in 2009. Conclusions To mitigate the gap between those needing and those receiving ART, more facilities were supported. The proportion of government facilities supported and the median number of persons treated at these facilities increased. This shift could potentially be sustainable as government sites reach more individuals and receive government funding. These results demonstrate that PEPFAR was able to support a massive scale-up of ART services in a short period of time.

The variations in the output power of a copper vapour laser resulting from H2 additive to neon buffer gas are investigated for a wide range of pulse repetition frequencies (3.2 to 19.7 kHz). Small improvements in laser output power (9%) were observed for ∼2% H2-Ne admixture at low repetition frequency, these improvements becoming progressively larger (up to 250%) as the repetition rate increased. These observations are consistent with added H2 modifying the interpulse kinetics, thereby altering the spatiotemporal evolution of the output pulse. In particular, the observed average output power increases at elevated repetition rates owing to both increased laser pulse energy and increased optimum pulse repetition frequency.

We assessed the determinants of health care funding allocations among South Africa's provinces and their effects on health care from 1996 through 2007.We performed multivariate regression of funding allocation data against measures of disease burden and health system infrastructure by province.Disease burden was increasingly negatively correlated with funding allocations and explained less than one quarter of the variation in allocations among provinces. Nearly three quarters of the variation in allocations was explained by preexisting hospital infrastructure and health care workers. The density of private hospitals in the preceding year was associated with greater government allocations (b(private) = 0.12; 95% confidence interval [CI] = 0.08, 0.15), but public hospital density in the preceding year was not (b(public) = 0.05; 95% CI = -0.02, 0.11). Greater allocations were associated with a higher number of doctors (b = 0.54; 95% CI = 0.34, 0.75) but fewer nurses (b = -0.37; 95% CI = -0.72,-0.25) in the same year.Regions with a greater capacity to spend funds received more funding and created more infrastructure than those with greater health needs. Historical infrastructure inequalities may have created an infrastructure-inequality trap, in which the distribution of funds to those with greater "absorptive capacity" exacerbates inequalities.

Beam shaping technology can greatly improve laser process efficiency by enabling parallel processes and increasing precision, quality and process stability. This paper outlines a system design, optical code analysis and the bench testing of a patented [1,2] laser beam homogenization and imaging system using prism beam splitting to produce a three spot array. The system uses a beam integrator to produce a rectangular spot that is split into three beams by two prisms. A second set of prisms directs the two outer beams onto an imaging lens and sets the pitch of the virtual spots. These beams, with the central beam, are imaged to form three spots with the required pitch. A prototype system design was developed for two approaches based on the first principles. The prototype system parameters were adjusted to minimize the requirements of the elements such as the imaging lens and prisms. Since the two systems require a relatively fast imaging lens, and there are aberrations associated with the prisms, a detailed optical design was conducted to determine the performance of the two approaches and to assess the complexity of the imaging lens. This paper will present the various positive and negative attributes of the two beam shaper designs within an optical system and how the best design was selected for prototyping and bench testing. Various data will be presented at each stage of design evaluation to the final bench test.

Double patterning lithography places significant demands not only on the optical performance of the light source (higher power, improved parametric stability), but also on high uptime in order to meet the higher throughput requirements of the litho cell. In this paper, we will describe the challenges faced in delivering improved performance while achieving better reliability and resultant uptime as embodied in the XLR 600ix light source from Cymer, announced one year ago. Data from extended life testing at 90W operation will be shown to illustrate these improvements.

High productivity is a key requirement for today's advanced lithography exposure tools. Achieving targets for wafers per day output requires consistently high throughput and availability. One of the keys to high availability is minimizing unscheduled downtime of the litho cell, including the scanner, track and light source. From the earliest eximer laser light sources, Cymer has collected extensive performance data during operation of the source, and this data has been used to identify the root causes of downtime and failures on the system. Recently, new techniques have been developed for more extensive analysis of this data to characterize the onset of typical end-of-life behavior of components within the light source and allow greater predictive capability for identifying both the type of upcoming service that will be required and when it will be required. The new techniques described in this paper are based on two core elements of Cymer's light source data management architecture. The first is enhanced performance logging features added to newer-generation light source software that captures detailed performance data; and the second is Cymer OnLine (COL) which facilitates collection and transmission of light source data. Extensive analysis of the performance data collected using this architecture has demonstrated that many light source issues exhibit recognizable patterns in their symptoms. These patterns are amenable to automated identification using a Cymer-developed model-based fault detection system, thereby alleviating the need for detailed manual review of all light source performance information. Automated recognition of these patterns also augments our ability to predict the performance trending of light sources. Such automated analysis provides several efficiency improvements for light source troubleshooting by providing more content-rich standardized summaries of light source performance, along with reduced time-to-identification for previously classified faults. Automation provides the ability to generate metrics based on a single light source, or multiple light sources. However, perhaps the most significant advantage is that these recognized patterns are often correlated to known root cause, where known corrective actions can be implemented, and this can therefore minimize the time that the light source needs to be offline for maintenance. In this paper, we will show examples of how this new tool and methodology, through an increased level of automation in analysis, is able to reduce fault identification time, reduce time for root cause determination for previously experienced issues, and enhance our light source performance predictability.

The ability to extend deep ultraviolet (DUV) lithography into the 32 and sub-32nm domain has more recently relied on improvements in source-mask optimization (SMO), double patterning (DP) and complex, pixellated illumination patterns. Yet these techniques require a commensurate improvement in the light source that powers the latest generation scanners in order to enable high performance at high throughput. This paper will show detailed performance results of the latest-generation light source from Cymer that incorporates flexible power with dramatic improvements in dose, wavelength and bandwidth stability.

An energy conversion efficiency of 80% for second-harmonic generation of 532-nm radiation from 1064-nm radiation has been achieved with a single KTP crystal and a commerical injection-seeded Q-switched Nd:YAG laser. A second-harmonic output of 720 mJ was generated with 900 mJ of incident 1064-nm radiation at 10 Hz.

Deep ultraviolet (DUV) lithography improvements have been focused on two paths: further increases in the effective numerical aperture (NA) beyond 1.3, and double patterning (DP). High-index solutions for increasing the effective NA have not gained significant momentum due to several technical factors, and have been eclipsed by an aggressive push to make DP a high-volume manufacturing solution. The challenge is to develop a cost-effective solution using a process that effectively doubles the lithography steps required for critical layers, while achieving a higher degree of overlay performance. As a result, the light source requirements for DP fall into 3 main categories: (a) higher power to enable higher throughput on the scanner, (b) lower operating costs to offset the increased number of process steps, and (c) high stability of optical parameters to support more stringent process requirements. The XLR 600i (6kHz, 90W @15mJ) was introduced last year to enable DP by leveraging the higher performance and lower operating costs of the ring architecture XLR 500i (6kHz, 60W @10mJ) platform currently used for 45nm immersion lithography in production around the world. In February 2009, the XLR 600ix was introduced as a 60/90W switchable product to provide flexibility in the transition to higher power requirements as scanner capabilities are enhanced. The XLR 600ix includes improved optics materials to meet reliability requirements while operating at higher internal fluences. In this paper we will illustrate the performance characteristics during extended testing. Examples of performance include polarization stability, divergence and pointing stability, which enable consistent pupil fill under extreme illumination conditions, as well as overall thermal stability which maintains constant beam performance under large changes in laser operating modes. Furthermore, the unique beam uniformity characteristics that the ring architecture generates result in lower peak energy densities that are comparable to those of a typical 60W excimer laser. In combination with the XLR's long pulse duration, this allows for long life scanner optics while operating at 15mJ.

The mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), is activated in experimental models of chronic pain, and is also activated by oestrogen. We used an established model of inflammatory trigeminal pain, injection of Complete Freund's Adjuvant (CFA) into the masseter muscle, to determine whether ERK activation may play a role in hormone-related trigeminal pain disorders. We measured withdrawal responses to stimulation of the masseter (V3, primary allodynia) and whisker pad (V2, secondary allodynia) using graded monofilaments. Oestrogen treatment in the presence of inflammation increased withdrawal response to stimulation of both masseter and whisker pad compared with inflammation alone, indicating an additive effect of inflammation and oestrogen on both primary and secondary allodynia. We examined ERK activation in trigeminal ganglia from each treatment group using western blot and immunohistochemistry. Both masseter inflammation and oestrogen treatment increased ERK activation, and combined treatment had an additive effect. Both masseter inflammation and oestrogen increased the percentage of pERK immunoreactive neurons in divisions 1 and 2 (V1/2), and combined treatment increased pERK immunoreactivity in V1/2 compared with inflammation alone. We stereotactically administered ERK antagonist U0126, or inactive control U0124, to the trigeminal ganglion of CFA+E2-treated rats. U0126 decreased withdrawal responses to mechanical stimulation of the whisker pad compared with U0124-treated rats. Because the secondary allodynia in V2 after inflammation in V3 was reduced by antagonizing ERK activation in the periphery, these data suggest a peripheral component to secondary allodynia mediated through ERK activation.

The need for improved lithography resolution has driven the development of light sources with ever shorter wavelength. Excimer lasers have extended the exposure wavelength down to 193nm. Further resolution extension will require the introduction of Extreme UV (EUV) light source technology at 13.5nm. The traditional light source driver at each technology node has been higher power which enables increased productivity. More recently, improved light source stability, driven by tighter CD and overlay budgets for Double Patterning processes, has become more important and developments in this area will be described. The leading challenge for insertion of EUVL is source power and lifetime, which are both necessary to ensure cost effective operation. The first Laser Produced Plasma (LPP) production source using a high power CO2 laser and tin droplet targets is described. High conversion efficiency has enabled high EUV power performance. Continuous operation up to 18 hours, with stable power output, has been demonstrated. High collection efficiency is obtained using a large (5sr) multilayer mirror collector optic. The first integrated source will be delivered to support scanners for process development and insertion of EUVL at the 22nm node. A roadmap for future generations of LPP sources with scalable power will be outlined.

The characteristics of high repetition rate CVL devices incorporating passive external heating have been investigated. Pre-heating of the CVL plasma tube using external heating has been shown to significantly reduce CVL warm-up time, while supplementary heating of the CVL plasma tube using external heating allows efficient CVL operation with reduced discharge power input without any degradation in output power.

Double patterning (DP) lithography is expected to be deployed at the 32nm node to enable the extension of high NA (≥1.3) scanner systems currently used for 45nm technology. Increasing the light source power is one approach to address the intrinsically lower throughput that DP imposes. Improved energy stability also provides a means to improve throughput by enabling fewer pulses per exposure slit window, which in turn enables the use of higher scanner stage speeds. Current excimer laser light sources for deep UV immersion lithography are operating with powers as high as 60W at 6 kHz repetition rates. In this paper, we describe the introduction of the XLR 600i, a 6 kHz excimer laser that produces 90W power, based on a recirculating ring technology. Improved energy stability is inherent to the ring technology. Key to the successful acceptance of such a higher power, or higher energy laser is the ability to reduce operating costs. For this reason, the recirculating ring technology provides some unique advantages that cannot be realized with conventional excimer lasers today. Longer intrinsic pulse durations that develop in the multi-pass ring architecture reduce the peak power that the optics are subjected to, thereby improving lifetime. The ring architecture also improves beam uniformity that results in a significantly reduced peak energy density, another key factor in preserving optics lifetime within the laser as well as in the scanner. Furthermore, in a drive to reduce operating costs while providing advanced technical capability, the XLR 600i includes an advanced gas control management system that extends the time between gas refills by a factor of ten, offering a significant improvement in productive time. Finally, the XLR 600i provides a novel bandwidth stability control system that reduces variability to provide better CD control, which results in higher wafer yields.

We report on a pulse-stacking technique in which a Cr, Nd:GSGG laser pumped by a high-pulse-rate (25 kHz) source is Q switched at lower pulse rates (submultiples of the pump rate) to achieve higher-output pulse energies and shorter pulse durations. For six pump pulses stacked, the output peak power increased by a factor of 10 compared with gain-switched output.

The output power of a kinetically enhanced Cu-vapor laser is shown to increase linearly with pulse repetition frequency to an experimental limit of 22 kHz. Output power of >150 W has been produced by a medium-scale (38-mm diameter, 1.55-m long) device operating at 22 kHz.

We have generated 15 W of UV (255-nm) radiation with an optical conversion efficiency of 28% by frequency doubling the 510.6-nm output of a high-beam-quality, high-power copper laser system in cesium borate lithium (CLBO). We found that the superior performance of CLBO relative to beta-barium borate is attributable largely to the small UV absorption and wide temperature acceptance bandwidth of CLBO, which reduces thermal dephasing during high-power UV generation.

We report the case of a 14-month-old male with d-transposition of the great arteries, ventricular septal defect, and pulmonary hypertension successfully treated with long-term sildenafil following cardiac surgery. To our knowledge, this is the first published report of long-term sildenafil treatment in a child after corrective cardiac surgery.

Summary form only given. Investigations of the influence of halogens in the buffer gas of high temperature copper vapour lasers led to the recent development of kinetically enhanced devices using H/sub 2/-HCl-Ne buffer gas mixtures. Kinetically enhanced copper vapour lasers (or KE-CVLs) have performance characteristics that far exceed those of conventional CVLs.