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.

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.

Laser produced plasma (LPP) systems have been developed as a viable approach for the EUV scanner light sources to support optical imaging of circuit features at sub-22nm 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. The status of first generation High Volume Manufacturing (HVM) sources in production and at a leading semiconductor device manufacturer is discussed. The EUV power at intermediate focus is discussed and the lastest data are presented. An electricity consumption model is described, and our current product roadmap is shown.

This paper describes the development of laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source architecture for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193nm immersion technology for sub-22nm critical layer patterning. In this paper we discuss the most recent results from high EUV power testing and debris mitigation testing on witness samples and normal incidence collectors. Subsystem performance will be shown including the CO2 drive laser, debris mitigation, normal incidence collector and coatings, droplet generation, laser-to-droplet targeting control, intermediate-focus (IF) metrology and system use and experience. In addition, a number of smaller lab-scale experimental systems have also been constructed and tested. This presentation reviews the experimental results obtained on systems with a focus on the topics most critical for an HVM source.

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.

Leading-edge scanners in fabs worldwide have particularly high system utilization and require peak levels of system throughput and availability. Laser gas exchanges typically occur daily on these systems (or every 100M pulses or less), with each exchange lasting up to 20 minutes. This downtime has a direct negative effect on availability, and if it is reduced, the productivity of the litho cell increases. This paper will outline the immediate success fabs have experienced after equipping scanners with Cymer's Gas Lifetime eXtension (GLXTM) technology, which increases scanner availability by extending the time between excimer laser gas exchanges by a factor of more than 10. To date, more than 100 leading-edge scanners feature Cymer's GLX technology, which has improved light source availability by more than 1.5 percent. Moreover, multiple chipmakers report more than 2 percent improvement in litho cell productivity due to GLX, corresponding to 2000 wafers/month increase for a 100,000 wafers/month fab. The increase in measured productivity is the leveraged benefit of reducing process interruptions around the refill cycle GLX technology extends the shot-based interval between gas refills to 1 billion pulses for Cymer's XLA light sources, and provides excellent stability in key optical performance parameters, such as bandwidth and dose stability over the entire gas life. This paper will provide extensive performance data during extended light source operation on litho cells equipped with GLX technology, and multiple use scenarios will be examined, including usage at memory and logic fabs. The paper will also discuss the performance of GLX2TM technology which further extends the maximum time between light source gas exchanges from 1B pulses to 2B pulses, and reduces downtime associated with gas refills by a factor of 20. The stability and productivity benefits of this new technology can be realized under all light source utilization scenarios. With GLX2, the refill interval at high utilization chipmakers is 3 weeks, and 4-8 weeks at lower utilization customers. Metrics illustrating the success of each of these capabilities will be presented. The second-generation of GLX technology was launched in July 2008 after chipmakers responded favorably to GLX performance metrics.

Increasing productivity demands on leading-edge scanners require greatly improved light source availability. This translates directly to minimizing downtime and maximizing productive time, as defined in the SEMI E10 standard. Focused efforts to achieve these goals are ongoing and Cymer has demonstrated significant improvements on production light sources. This paper describes significant availability improvements of Cymer light sources enabled by a new advanced gas management scheme called Gas Lifetime eXtensioTM (GLTM) control system. Using GLX, we have demonstrated the capability of extending the pulse-based interval between full gas replenishments to 1 billion pulses on our XLA light sources, as well as significant extension in the time-based interval between refills. This represents a factor of 10X increase in the maximum interval between full gas replenishments, which equates to potential gain of up to 2% in productive time over a year for systems operating at high utilization. In this paper, we provide performance data on extended (1 billion pulse) laser operation without full gas replenishment under multiple actual practical production environments demonstrating the ability to achieve long gas lives with very stable optical performance from the laser system. In particular, we have demonstrated that GLX can provide excellent stability in key optical performance parameters, such as bandwidth, over extended gas lives. Further, these stability benefits can be realized under both high and low pulse accumulation scenarios. In addition, we briefly discuss the potential for future gas management enhancements that will provide even longer term system performance stability and corresponding reductions in tool downtime.

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.

Increasing throughput demands on leading edge scanners are requiring greatly improved light source availability. This translates directly to minimizing downtime and maximizing productive time, as defined in the SEMI E 10 standard. One positive contributor to improving productive time is the minimization of the light source stoppage for entire Halogen gas replenishment. This paper describes availability improvements of Cymer XLA and 7000 series light sources by using advanced gas management schemes to minimize entire gas replenishment impact to productive time. Recent augmented gas control algorithms have demonstrated multiple times extension of gas life through advanced gas replenishment methods and higher performance estimators. Along with these improvements to gas management, major efforts in light source fault reduction, module lifetime extension and optimization of module replacement, will provide significantly increased combined light source\scanner availability.

Improved optical proximity correction is needed to meet the tighter CD control budgets for advanced lithography processes. Laser bandwidth variation is one of the factors that contributes to the optical proximity effect (OPE). Advanced active control technologies for bandwidth stabilization and improved optical proximity correction (OPC) models incorporating laser spectral characteristics can be used to reduce this contribution to OPE error.