Maximizing efficiency in complex laser systems by integrating machine learning and optimizing exchange parts. Challenges include reducing maintenance time, improving module lifetime, and implementing proactive maintenance through data analysis. Specific developments include hardware improvements, skill enhancements for service engineers, extending module lifetime, and data analysis for lifetime prediction.
In excimer laser operation, the maintenance choices by the field service engineer are critical to maximize laser performance while minimizing laser downtime, part replacement expenses, and overall touches to the instrument. To optimize maintenance choices, the engineer must estimate future internal performance of the laser, the impact of each consumable part and their interactions, the impact of operational settings and their interactions, and the optimal timing for each maintenance event. To aid engineers’ decision-making, a deep learning-based laser simulator was developed. The simulator forecasts and plots laser performance under one or multiple maintenance scenarios where each scenario may each have different maintenance timing and multiple maintenance operations such as parts replacement and other operational choices. The simulator is based on a deep recurrent neural network (RNN) with a seq2seq encoder-decoder architecture. Through the encoder, this architecture leverages model inputs that include historical laser performance and configuration data in a temporal dependence structure. Through the decoder, the architecture also captures temporally specific information about future laser operation. By adjusting the decoder inputs, the model forecasts can be altered to reflect future laser maintenance scenarios under consideration. The RNN is deployed in a software plugin for Fabscape® which provides a graphical user interface with interactive elements for field service engineers to forecast, compare maintenance operations, and compare maintenance timing on future laser performance. Ultimately, by simulating the impact of maintenance through the deep learning model and GUI, field service engineers can gain insights to enhance proactive maintenance and plan upcoming service events.
Multiple patterning ArF immersion lithography has been expected as the promising technology to meet tighter leading edge device requirements. To enhance the resolution and productivity for multiple-patterning application, key light source performances are spectral bandwidth stability and wavelength stability. The increased spectral bandwidth stability contributes to more precise critical dimension (CD) control and improves device yield. The increased wavelength stability can realize accurate focus and improve overlay accuracy. Our new spectral bandwidth control module improves E95 spectral bandwidth stability. The spectral bandwidth has deviations by thermal history with light source operations. It should be always controlled tightly even after a quiescent interval, such as wafer loading. In our laser system, a spectral bandwidth is controlled by adjusting the wavefront of a laser beam using a two-lens optical system within a resonator. A high speed actuator equipped the movable lens enables E95 spectral bandwidth stability to be less variation. New designs of drive mechanism suppress the lens vibration and spectral bandwidth error. This technology enables 3-sigma of E95 spectral bandwidth field average to be under 5 fm. This large shrinkage for E95 spectral bandwidth stability is the key to improve larger focus budgets for a leading edge processes. A new designed line narrowing module (LNM) improves wavelength stability. The wavelength is controlled by changing the rotation of a beam expander prism using actuator. Wavelength stability is improved further by the anti-vibration structure of the actuated prism in the LNM. The new design prism holding mechanisms reduce the mass of actuator load. This increases the stiffness of the system and suppresses the vibration of the prism rotation. New LNM reduce wavelength stability about 20%. The improvement in wavelength stability contributes to accurate focus and overlay. In addition, the lifetime of LNM is extending to reduce the Cost of Operation (CoO) and the light source downtime. A new ArF excimer laser, GT66A, maximizes device yield, process productivity and minimizes the operational costs for chipmakers.
Multi-patterning techniques with ArF immersion lithography is expected to continue as main solution for manufacturing IC chips. The reduction of laser downtime has great impact on the productivity of chipmakers. The laser downtime is closely related to the lifetime of consumable parts of the laser. Gigaphoton has developed longer life excimer laser chamber which contains a new technology “New-type G-electrode”. This new type excimer laser chamber demonstrated 1.3 times longer lifetime than conventional excimer laser chamber. Gigaphoton has also introduced new design of LNM (Line Narrowing Module) last year. Through combines timing of maintenance of new type excimer laser chamber and new type LNM, it’s expected that the downtime of the laser is significantly reduced than ever. This leads to the improvement of the throughput on ArFi lithography.
KEYWORDS: Solid state lasers, Excimer lasers, Laser systems engineering, Deep ultraviolet, Optical amplifiers, Amplifiers, Crystals, High power lasers, Semiconducting wafers, Fiber amplifiers
We have been developing a hybrid 193 nm ArF laser system that consists of a solid state seeding laser and an ArF excimer laser amplifier for power-boosting. The solid state laser consists of an Yb-fiber-solid hybrid laser system and an Er-fiber laser system as fundamentals, and one LBO and three CLBO crystals for frequency conversion. In an ArF power amplifier, the seed laser passes through the ArF gain media three times, and an average power of 110 W is obtained. As a demonstration of the potential applications of the laser, an interference exposure test is performed.
Since 2002, we have been developing a CO2-Sn-laser plasma produced (LPP) extreme-ultraviolet (EUV) light source, the most promising solution as the 13.5-nm high-power (>200 W) light source for high-volume manufacturing (HVM) EUV lithography. Because of its high efficiency, power scalability, and spatial freedom around plasma, we believe that the CO2-Sn-LPP scheme is the most feasible candidate as the light source for EUVL. By now, our group has proposed several unique original technologies, such as CO2 laser-driven Sn plasma generation, double-laser pulse shooting for higher Sn ionization rate and higher CE, Sn debris mitigation with a magnetic field, and a hybrid CO2 laser system that is a combination of a short-pulse oscillator and commercial cw-CO2 amplifiers. The theoretical and experimental data have clearly demonstrated the advantage of combining a laser beam at a wavelength of the CO2 laser system with Sn plasma to achieve high CE from driver laser pulse energy to EUV in-band energy. We have the engineering data from our test tools, which include 20-W average clean power, CE = 2.5%, and 7 h of operating time; the maximum of 3.8% CE with a 20-μm droplet, 93% Sn ionization rate, and 98% Sn debris mitigation by a magnetic field. Based on these data, we are developing our first light source for HVM: "GL200E." The latest data and the overview of EUV light source for the HVM EUVL are reviewed in this paper.
193nm ArF immersion microlithography has been used widely in high-volume manufacturing, and it is considered to be
the main solution below 32 nm node until extreme ultraviolet (EUV) lithography becomes ready. Laser systems are now
enlarging its function and capability to meet various applications. In this paper we report a newly developed solution for
focus drilling technique applied to increase the depth of focus (DoF) for patterning contacts, vias and trenches. The laser
light is stabilized at any E95 in the range from 0.3 pm to 2.5 pm, where E95 is defined as the width of the spectral range
that contains 95% of the integrated spectral intensity. The high-range bandwidth is realized by introducing a newly
developed line narrowing module (LNM) in the oscillator resonator. The bandwidth is measured with the on-board
Fabry-Perot etalon and well controlled. This technique is easy upgradable to Gigaphoton latest GT62A-1SxE with the
flexible output power (60W - 90W) and stabilized spectrum (E95=0.3pm). In comparison to another focus drilling
technique where the large DoF is achieved by tilting a wafer stage during scan, the increase of the bandwidth of light
source has much smaller impact on the required performance of the scanner such as productivity, overlay and critical
dimension uniformity (CDU). In the paper we present the data that indicate the increases in DoF with broadening of the
laser spectrum as well as imaging and overlay results obtained at high bandwidth.
ArF immersion technology has been used widely in volume production for 45nm node. For 32nm node and beyond,
double patterning technology with ArF immersion lithography is considered to be the main stream solution until EUV is
ready.
Our target is to reduce CoO(Cost of ownership) and we aim to develop for ecology and high durability laser. We will
introduce the latest performance data of the laser built for ArF immersion lithography under the EcoPhoton concept.
Eco-photon concept:
-CoC (Cost of Consumable)
-CoD (Cost of Downtime)
-CoE(Cost of Energy & Environment)
We have developed flexible and high power injection-lock ArF excimer laser for double patterning, GT62A-1SxE
(Max90W/6000Hz/Flexible power with 10-15mJ/0.30pm (E95)) based on the GigaTwin platform5). A number of
innovative and unique technologies are implemented on GT62A-1SxE. In addition, GT62A-1SxE is the laser matching
the enhancement technology of advanced illumination systems. For example, in order to provide illumination power
optimum for resist sensitivity, it has extendable power from 60W to 90W.
We have confirmed durability under these concept with the regulated operation condition with flexible power 60-90W.
We show the high durability data of GT62A-1SxE with Eco-Photon concept. In addition to the results the field reliability
and availability of our Giga Twin series (GT6XA). We also show technologies which made these performances and its
actual data. A number of innovative and unique technologies are implemented on GT62A.
ArF immersion technology is spotlighted as the enabling technology for the 45nm node and beyond. Recently, double
exposure technology is also considered as a possible candidate for the 32nm node and beyond. We have already released
an injection lock ArF excimer laser, the GT61A (60W/6kHz/10mJ/0.30pm) with ultra line-narrowed spectrum and
stabilized spectrum performance for immersion lithography tools with N.A.>1.3, and we have been monitoring the field
reliability data of our lasers used in the ArF immersion segment since Q4 2006.
In this report we show field reliability data of our GigaTwin series - twin chamber ArF laser products. GigaTwin series
have high reliability. The availability that exceeds 99.5% proves the reliability of the GigaTwin series.
We have developed tunable and high power injection-lock ArF excimer laser for double patterning, GT62A
(Max90W/6000Hz/Tunable power with 10-15mJ/0.30pm (E95)) based on the GigaTwin platform. A number of
innovative and unique technologies are implemented on GT62A.
- Support the latest illumination optical system
- Support E95 stability and adjustability
- Reduce total cost (Cost of Consumables, Cost of Downtime and Cost of Energy & Environment)
In advanced lithography processes, immersion lithography technology is beginning to be used in volume production at
the 45-nm technology node. Beyond that, double-patterning immersion lithography is considered to be one of the
promising technologies -meeting the requirements of the next-generation 32-nm technology node. Light source
requirements for double patterning lithography tool are high power and high uptime to enhance economic efficiency, as
well as extremely stable optical performances for high resolution capabilities.
In this paper, the GT62A, Argon Fluoride (ArF) excimer laser light source which meets these requirements is introduced.
The GT62A has an emission wavelength of 193-nm, a power output of 90 W and a repetition rate of 6,000 Hz. The dose
uniformity of the GT62A was improved for reduction of Critical Dimension (CD) variation and better Critical
Dimension Uniformity (CDU). A stable wavelength and a spectrum bandwidth of the GT62A satisfy the requirements of
the high resolution lithography tools which need the steady focus stability. In addition, we verified by simulation that the
spectrum bandwidth control in the GT62A contributes to Depth of Focus (DOF) enhancement. The new technology for
the light source and detailed optical performance data are presented.
ArF immersion technology is spotlighted as the enabling technology for the 45nm node and beyond. Recently, double
exposure technology is also considered as a possible candidate for the 32nm node and beyond. We have already released
an injection lock ArF excimer laser, the GT61A (60W/6kHz/10mJ/0.35pm) with ultra line-narrowed spectrum and
stabilized spectrum performance for immersion lithography tools with N.A.>1.3, and we have been monitoring the field
reliability data of our lasers used in the ArF immersion segment since Q4 2006. We show GT series reliability data in the
field. GT series have high reliability performance. The availability that exceeds 99.5% proves the reliability of the GT
series. We have developed high power injection lock ArF excimer laser for double patterning, the GT62A
(90W/6000Hz/15mJ/0.35pm(E95)) based on the GigaTwin (GT) platform. Number of innovative and unique
technologies are implemented on GT62A in order to reduce running cost of laser. We have introduced unique technology
to enable 40 billion pulse lifetime of laser chambers to drastically reduce running cost. In addition, we have improved
lifetime of Line Narrowing Module significantly by changing optical path. Furthermore, the extension of gas refill
intervals was achieved by introducing new gas supply module and sophisticated gas control algorithm. We achieved the
reduction of operation cost and down time by introducing these three technologies.
ArF immersion technology is spotlighted as the enabling technology for below 45nm node. Recently, double exposure
technology is also considered for below 32nm node. We have already released an injection lock ArF excimer laser with
ultra-line narrowed and stabilized spectrum performance: GT61A (60W/6kHz/ 10mJ/0.35pm) to ArF immersion market
in Q4 2006. The requirements are: i) higher power ii) lower cost of downtime for higher throughput iii) greater
wavelength stability for improved overlay and iv) increased lifetimes for lower operation costs.
We have developed high power and high energy stability injection lock ArF excimer laser for double patterning: GT62A
(90W/6000Hz/15mJ/0.35pm) based on the technology of GT61A and the reliability of GigaTwin (GT) platform. A high
power operation of 90W is realized by development of high durability optical elements. Durability of the new optics is at
least 3 times as long as that of the conventional optics used in the GT61A. The energy stability is improved more than
1.5 times of performance in the GT61A by optimizing laser operational conditions of the power oscillator. This
improvement is accomplished by extracting potential efficiency of injection lock characteristic. The lifetime of power
oscillator, which is one of the major parts in cost of ownership, is maintained by using higher output of the power supply.
The Argon Fluoride (ArF) immersion lithography is now shifting to mass production phase for below 45nm node. For a
laser light source in this node, narrower and more stable spectrum performance is required. We have introduced GT61A
ArF laser light source (60W/6kHz/10mJ/0.35pm) with spectrum E95 stabilization system which meets these
requirements. The narrow and stabilized spectrum performance was achieved by developing an ultra line narrowing
module and Bandwidth Control Module (BCM). It contributes to the reduction of differences of the spectrum during
exposure over a wafer, wafer to wafer, during machine lifetime and machine to machine for every light source. Stable
laser performance is obtained for mass production. The GT61A integrated on a common and already reliability-proven
GigaTwin (GT) platform, and its inherited reliability is proved with the availability over 99.5% in the field.
KEYWORDS: Molybdenum, High power lasers, Laser systems engineering, Laser applications, Light sources, Systems modeling, Semiconductors, Lithography, Electrodes, Pulsed laser operation
Reliable high power 193nm ArF light source is desired for the successive growth of ArF-immersion technology for 45nm node generation. In 2006, Gigaphoton released GT60A, high power injection locked 6kHz/60W/0.5pm (E95) laser system, to meet the demands of semiconductor markets. In this paper, we report key technologies for reliable mass production GT laser systems and GT60A high durability performance test results up to 20 billion pulses.
The GT61A ArF laser light source with ultra line narrowed spectrum, which meets the demand of hyper NA (NA > 1.3)
immersion tool, is introduced. The GT61A aims at improving spectrum performance from value E95 0.5pm of GT60A.
The spectrum performance 0.3pm or less was achieved by developing an ultra line narrowing module newly.
Moreover, in 45nm node, since it indispensably requires OPC (optical proximity correction) and a narrower process
window, improved stabilization of spectrum performances was performed by bandwidth control technology. Newly
designed Bandwidth Control Module (BCM) includes high accuracy measurement module which support the narrower
bandwidth range and active bandwidth control module. It also contributes to the reduction of the tool-to-tool differences
of the spectrum for every light source.
Last year Gigaphoton introduced a 45-W ArF excimer laser, model GT40A, to semiconductor markets as a light source for 65 nm lithography generation. The GT40A is based on injection lock technology with G-electrode, magnetic bearing and high resolution technologies for high reliability and long lifetime. As a result, GT40A showed the stable performance during the chamber maintenance interval of over 15 billion pulses. In this paper we will report the longterm stability of GT40A.
High-repetition-rate ArF excimer lasers are needed to enable high throughput and energy-dose stability in 193-nm scanner systems. Last year we described a 4-kHz ArF excimer laser with long pulse duration, which can narrow the spectral bandwidth by increasing the number of round trips and reduce optical damage from low-peak power. The design of the 4-kHz ArF excimer laser has been improved for mass production. Operating rates exceeding 4 kHz are needed to optimize lasers for next-generation technologies that can enable high NA and the development of high-throughput scanners. We have analyzed the possibilities of achieving repetition rates higher than 4 kHz. The discharge width was reduced by about 25 % with a variation of the electric field at the discharge section, and the gas flow and gas-mixture conditions were improved. As a result, we obtained the following performance characteristics: 42-W average power, 3.5 % pulse-to-pulse energy stability of sigma, and a 44-ns integral-square pulse width at 6 kHz with a bandwidth of below 0.45 pm in FWHM. We concluded that developing 6-kHz ArF excimer lasers for next-generation 193-nm lithography is feasible.
KrF excimer laser lithography has applications for the less-than-130-nm-design rule by improving the exposure technology, i.e., super-resolution technology. We therefore developed a 4-kHz KrF excimer laser which corresponds to the next generation's high throughput and high number of aperture (NA) scanner requirements, and achieved low cost of operation (CoO) for this light source for mass production uses. We estimated the basic performance requirements of our device, and developed the necessary high repetition rate operation technology that corresponds to a high throughput scanner, and achieved 4-kHz/30-W laser output. We also developed pulse stretching technology for ultra line narrowing, which can accommodate the high NA lens, and achieved more than 30 ns pulse width (Tis). We can thus expect less than 0.45-pm spectral bandwidth (FWHM). Moreover, the relation of the repetition rate operation and main module life was evaluated, and the optimal repetition frequency, which considers CoO, was adopted.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.