193nm ArF eximer lasers are expected to continue to be the main solution in photolithography, since advanced
lithography tecnologies such as Multiple patterning and Self-aligned double patterning (SADP) are being developed. In
order to appliy these tecnologies to high-volume semiconductor manufactureing, the key is to contain chip
manufactureing costs. Therefore, improvement on Reliability, Availability and Maintainability of ArF excimer lasers is
important.[1] We works on improving productivity and reducing downtime of ArF exmer lasers, which leads to
Reliability, Availability and Maintainability improvemnet. First in this paper, our focus drilling tecnique, which
increases depth of focus (DoF) by spectral bandwidth tuning is introdueced. This focus drilling enables to increase DoF
for isolated contact holes. and it not degrades the wafer stage speed.[2] Second, a technique which eables to reduce gas
refill time to zero is introduced. This technique reduces downtime so Availavility is expected to improve. In this paper,
we report these tecniques by using simulation resutls and partially experimental resutls provided by a semiconductor
manufacturer.
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.
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.
Mass production in 193 nm lithography is now starting and its target node is moving from 90 nm to 65 nm. The main performance requirement of ArF excimer laser in this situation is high power with ultra narrow spectrum for higher throughput. The other hand, higher reliability and lower cost of ownership (CoO) are strongly hoped in mass production because CoO of ArF excimer laser is still higher than that of KrF excimer laser. We have already reported the 4 kHz ArF excimer laser for mass production, model G42A, which has an 20 W of average power, spectral bandwidth less than 0.3 pm (FWHM) and a spectral purity less than 0.75 pm (E95). We applied some technologies to G42A for achieving the high reliability and long lifetime. As a result, G42A showed the stable performance during the lifetime of over 10 billion pulses. In this paper, we report the long-term stability of G42A. And also, we introduce the reliability data of G40A series, which is the previous 4 kHz ArF excimer laser model.
193-nm lithography is going to move from pre-production phase to mass production phase and its target node become narrowing from 90 nm to 65 nm. In these situations, the laser manufacture needs to provide the high durable ArF excimer laser, which has superior spectrum performance. Gigaphoton has already introduced 4 kHz ArF laser (model G41A) to 193-nm lithography market, which produce 20 W and spectrum bandwidth of 0.35 pm (FWHM). G41A has showed high reliability and long lifetime over 5 billion pulses. In this paper, we report on the 4 kHz ArF excimer laser for mass production, model G42A, which has 20 W, spectral bandwidth less than 0.3 pm (FWHM) and a spectral purity less than 0.75 pm (E95).
We have developed a 4-kHz ArF excimer laser with ultra-narrow bandwidth, which is applicable to high-NA scanners for sub-0.13-micrometers microlithography. In this paper, we describe a 4-kHz ArF excimer laser for mass production: the model G40A, which has an output power of 20 W and energy dose stability of less than +/- 0.3% (20-ms window) at 4 kHz. This dose stability is comparable to the performance of an existing 2-kHz ArF excimer laser, the model G20A. The new laser also has the following specifications: a long pulse duration of over 40 ns, spectral bandwidth of less than 0.35 pm (FWHM), and spectral purity of less than 1.0 pm (95%). These characteristics are better than those of the G20A. A lifetime test of over 7 billion pulses has been conducted at 4-kHz operation. The new laser has maintained an energy dose stability of less than +/- 0.3% (20-ms windows) and demonstrated performance suitable for mass production even after over 7 billion pulses.
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