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Latest ArF immersion lithography has been positioned as the promising technology to meet tighter process control requirements with providing highly efficient productivity, simultaneously. The most important features for the next generation lightsources are the improvement of chip yield and tool availability in manufacturing. One of the key requirements for lightsource is E95% bandwidth, which has become more critical parameter for enhancing process margin and improving optical characteristic. Lower E95% bandwidth enables to increase imaging contrast which demonstrates better OPE characteristic with better resolution as well as improved E95% bandwidth stability that providing CD uniformity on wafer.
A newly designed line narrowing module (LNM) enables to lower E95% bandwidth from the standard 300fm to 200fm. The large shrinkage for E95% bandwidth is achieved by the sophisticated design in LNM which enables to lower thermal wave front aberration reducing heat effect at optical elements and mechanical components during lasing the lights. Lower E95% bandwidth reduces a focus blur in the formulated image that is generated from the chromatic aberration with projection lenses in ArF immersion lithography system.
In the other hand, it is essential to improve the productivity by means of reducing downtime, the lifetime of consumable modules such as a chamber and a line narrowing module (LNM) is needed to be extended. New electrodes as called “RAIKIRI” electrode with chamber enable lifetime extension from 60 billion pulses (Bpls) to 80 Bpls. Furthermore, new optical design in LNM enables the lifetime to extend from 60 Bpls to 110 Bpls. Hence, the GT65A, maximizes device yield, process productivity therefore provides optimum in the operational costs for chipmakers.
In the presentation, the latest development status and performances on GT65A will be discussed.
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