Over 50 EUV scanners are installed at customer factories and being used in high volume manufacturing (HVM) of leading semiconductor devices. The latest generation of EUV sources are operating at 250W while meeting all other requirements. Future EUV scanners are projected to require more stable EUV and higher powers >600W to meet throughput requirements.
In this paper, we provide an overview of a the latest advances in the laboratory for tin laser-produced-plasma (LPP) extreme-ultraviolet (EUV) sources at 13.5nm enabling HVM at the N5 node and beyond, highlighting crucial EUV source technology developments needed to meet future requirements for EUV power and stability. This includes the performance of subsystems such as the Collector and the Droplet Generator.
In this paper, we provide an overview of state-of-the-art technologies for incoherent laser-produced tin plasma extreme-ultraviolet (EUV) sources at 13.5nm with performance enabling high volume semiconductor manufacturing (HVM). The key elements to development of a stable and reliable source that also meet HVM throughput requirements and the technical challenges for further scaling EUV power to increase productivity are described. Improvements in availability of droplet generation and the performance of critical subsystems that contribute to EUV collection optics lifetime toward the one tera-pulse level, are shown. We describe current research activities and provide a perspective for EUV sources towards the future ASML Scanners.
We provide an overview of laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source performance to enable high volume manufacturing and improvements in various technologies for scaling output power of the source. Several companies have multiple systems and are ramping toward production, we will show current output and availability of sources and describe their readiness for HVM. We will show improvements to source architecture that facilitated the increase of EUV power to 250W, and the technical challenges for power scaling of key source parameters and subsystems. The performance of critical subsystems such as the Droplet Generator and Collector protection will be shown, with emphasis on stability and lifetime. Finally, we will describe current research activities and provide a perspective for LPP EUV sources towards 500W.
In this paper, we provide an overview of various technologies for scaling tin laser-produced-plasma (LPP) extremeultraviolet (EUV) source performance to enable high volume manufacturing (HVM). We will show improvements to source architecture that facilitated the increase of EUV power from 100W to 250W, and the technical challenges for power scaling of key source parameters and subsystems. The performance of critical subsystems such as the Droplet Generator and Collector protection will be shown, with emphasis on stability and lifetime. Finally, we will describe current research activities and provide a perspective for LPP EUV sources towards 500W.
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.
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.
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.
Demand for increased semiconductor device performance at low cost continues to drive the requirements for shrinking the geometry of features printed on silicon wafers. Argon fluoride (ArF) excimer laser systems operating at 193 nm and producing high output power played a key role in patterning of the most advanced features for high volume deep ultraviolet (DUV) lithography over the last decade. Lithographic patterning has progressed from ArF dry to ArF immersion (ArFi) to double and multiple patterning applications, with increasingly tight requirements for the quality of light at 193 nm and improved system reliability. This drove the transition from single chamber laser systems to dual chamber systems with ring cavity amplifier architectures. We are presenting a flexible 90-120W ArFi excimer laser system, developed for high volume multiple patterning manufacturing as well as 450mm wafer applications. Light source design is based on dual-chamber architecture with ring cavity power amplifier.
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.
High performance lithography is increasingly demanding light sources to deliver laser light over a much larger range of
stabilized bandwidths. The applications range from improved optical proximity correction (OPC) to the high-speed
printing of vias and contact holes, through a process called focus drilling. Several advances in light source technology
must integrate to provide the improved bandwidth performance required by the industry.
This paper will outline three of the core technologies developed by Cymer and integrated into its most advanced XLATM
and XLRTM series light sources to meet this need. Novel improvements in line narrowing offer the actuation necessary
to tune the bandwidth over the large range. Advanced bandwidth metrology yields accurate measurements of the
bandwidth over the wide range. And new controls and feedback algorithms provide the integration to stabilize the
bandwidth to the desired target. The result provides laser light bandwidths that can be tuned to and accurately stabilized
at any spectral E95 target from 0.3 pm to 1.6 pm, while maintaining all other laser performance parameters. The feature
is called focus drilling. Focus drilling extends the utility of Cymer XLA and XLR lasers by adding more flexibility to
the light source, allowing the end-user chipmaker to select the exact properties of the laser light necessary for a wider
range of process steps.
The article will discuss the above technologies and emphasize their important aspects. It will also highlight some of the
key performance aspects using data from Cymer's testing. Some of the design features and trade-offs will be provided,
and a few of the relevant metrics will be presented and justified. Finally, potential future improvements to the
technology will be presented.
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 OPE signature of a lithographic stepper or scanner has become a very important characteristic of the tool, as it determines the OPC correction to be applied to reticles exposed on that tool. The signature depends on a variety of detailed information about the scanner lens and illuminator, which in turn depend on the characteristics of the illumination light from the laser. Specifically, changes in the laser bandwidth should impact OPE as the lens exhibits some chromatic aberration. Tool-to-tool differences and time fluctuation of the laser bandwidth could cause variations in OPE tool matching and stability. To assess this, a detailed study of laser bandwidth effects on OPE was performed. A sensitive spectrometer was connected to a litho laser, allowing careful measurements of both the FWHM and E95 parameters of the laser spectral profile. Lithographic modeling using the chromatic response of the lens was run in order to predict effects. Exposures of CD through pitch were made to test the modeling. Finally, the bandwidth data was correlated with litho sensitivity to create a "bandwidth effect", put in context with the other common scanner parameters affecting OPE.
The variation of CD with pitch, or Optical Proximity Effect (OPE), in an imaging system shows a behavior that is characteristic of the imaging and process conditions and is sensitive to variations in those conditions. Maintaining stable process conditions can improve the effectiveness of mask Optical Proximity Correction (OPC). One of the factors which affects the OPE is the spectral bandwidth of the light source. To date, passive bandwidth stabilization techniques have been effective in meeting OPE control requirements. However, future tighter OPE specifications will require advanced bandwidth control techniques. This paper describes developments in active stabilization of bandwidth in Cymer XLA and 7010 lasers. State of the art on board metrology, used to accurately measure E95 bandwidth, has enabled a new array of active control solutions to be deployed. Advanced spectral engineering techniques, including sophisticated control algorithms, are used to stabilize and regulate the bandwidth of the light source while maintaining other key performance specifications.
The first generation MOPA-based ArF laser XLA-100 was introduced in January 2003 in response to the needs of the high NA ArF scanners for higher power and narrower spectral bandwidth. The second generation product XLA-105 was introduced in early 2004. This paper presents our third generation MOPA-based ArF laser product XLA-200 that is designed and engineered to meet the light source requirements of the ArF immersion lithography. It is expected to be used for 65-nm and 45-nm volume production of semiconductor devices. The XLA-200 is capable of producing a 60W of ultra-line-narrowed 193nm light with the FWHM bandwidth of less than 0.15pm and the E95% integral bandwidth of less than 0.35pm. It features state-of-the-art on-board bandwidth metrology tool that measures E95% bandwidth as well as FWHM. Real-time accurate bandwidth information can be utilized for lithography exposure tool feedback control. The improved dual-chamber laser gas control ensures excellent bandwidth stability, which enables tighter CD control. Together with a lower cost of ooperation, the XLA-200 sets a new performance level for the dual chamber 193nm light source for microlithography.
Etalon spectrometers often provide the practical means for providing pulse-resolved spectral metrology of line-narrowed excimer laser lithographic light sources because of their relative simplicity and physical robustness. A typical application uses the full-width at half-maximum intensity (FWHM) of an etalon fringe to infer the FWHM bandwidth of an unknown input spectrum. These devices are often used in a regime where the ratio of the width of the spectrometer impulse-response to the bandwidth of the source spectrum is close to (or greater than) unity. In this regime, the fringe width may have non-negligible sensitivity to details of the source spectral shape other than its FWHM, including asymmetry and spectral purity. This paper details this sensitivity and provides suggestions for techniques that can either suppress the effect or apply it to some advantage such as estimation of a spectral purity metric, e.g., the 95%-enclosed energy width (E95%) of the source spectrum.
Since the announcement in March 2002 of plans to develop an advanced light source to meet the future spectral power and cost requirements of photolithography, we have made significant progress in the development and productization of the core technology for an ultra line-narrowed, excimer light source based on a master oscillator-power amplifier (MOPA) approach. In this paper, we will focus on the architecture and performance of the first generation of production-ready, MOPA-based ArF light sources developed at Cymer, Inc. This first generation of MOPA-based ArF light sources is referred to as the XLA 100 product series.
Using a laser that is frequency-locked to a Fabry-Perot etalon of high finesse and stability, we probed the 5d106s 2S1/2(F equals O, mF equals O) $ARLR 5d96s22D5/2 (F equals 2, mF equals O) electric-quadrupole transition of a single laser-cooled 199Hg+ ion stored in a cryogenic radio-frequency ion trap. We observed Fourier-transform limited linewidths as narrow as 6.7 Hz at 282 nm (1.06 X 1015 Hz). The functional form and estimated values of some of the frequency shifts of the 2S1/2 $ARLR 2D5/2 clock transition (including the quadrupole shift), which have been calculated using a combination of measured atomic parameters and ab initio calculations, are given.
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