Development of Sn-fueled high-power DPP EUV source for enabling HVM

Teramoto, Y.; Narihiro, Z.; Yamatani, Daiki; Yokoyama, Tsugio; Bessho, Kazunori; Joshima, Yuki; Shirai, Takahiro; Mouri, S.; Inoue, Takahiro; Mizokoshi, Hiroshi; Niimi, Gohta; Hosokai, Tomonao; Yabuta, Hironobu; Paul, K.C.; Takemura, T.; Yokota, Toshio; Kabuki, Kiyoyuki; Miyauchi, Koji; Hotta, Kazuaki; Sato, Hiroto

doi:10.1117/12.728711

Cited by 15 publications

(2 citation statements)

References 9 publications

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“…Several debris mitigation techniques are being developed to slow down the contamination process. With debris mitigation technique (DMT), engineers in USHIO reported the Sn debris build up rate as 3.2 x 10 -6 nm/pulse whereas without DMT, 3.9 x 10 -4 nm/pulse [1]. Therefore, without any cleaning process, debris mitigation technique alone can not solve Sn contamination issue.…”

Section: Introductionmentioning

confidence: 97%

Plasma Sn cleaning integrated in EUV source system

2008

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Extreme ultraviolet lithography (EUVL) is a potential candidate for the next generation lithography techniques, which will use Xe or Sn as a main fuel to produce EUV light. However, the industry has favored to use Sn as main fuel in EUVL systems because of its high conversion efficiency over Xe. Sn has an advantage of producing more light, but on the other hand its condensable nature is a real threat to the reflective mirrors which are used to collect the EUV light at intermediate focus. Center for Plasma Material Interactions (CPMI) at the University of Illinois has studied plasma etching as a potential method of Sn removal from collector optics. RF-driven chlorine plasma is used to etch Sn from mirror samples. Previously we reported high selectivity of Sn over several EUV compatible mirror materials. The increased confidence in this technology had led us to perform cleaning experiments on real Sn contaminated samples exposed in an EUV source and the results obtained have been very encouraging. Small mock up shells (same as in the grazing incidence collector optics system) were constructed at CPMI and chlorine etching was performed at different samples placed at different locations on multi-shell collector mock up in ICP-RIE chamber. Post cleaning material characterization results of samples shows that chlorine can potentially clean Sn off of collector optics (Ru was used in this study as a mirror sample). Realizing this as a viable cleaning solution, we have stepped further and performed a full size cleaning test in the Xtreme's XTS 13-35 EUV source. Large mock up with appropriate dimension was placed in the EUV source chamber and the cleaning system was installed to etch Sn away from Ru surface. This study compares the cleaning results in a real system scale with the previous simulated system. The comparison shows how to improve the Sn cleaning system in the EUV source chamber. Results are encouraging and may enable source suppliers to integrate this technology in their respective sources. Cleaning rate was measured as >100nm/min using ion sputtered Sn samples.

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Section: Introductionmentioning

confidence: 97%

Plasma Sn cleaning integrated in EUV source system

2008

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“…Therefore, costly replacing or/and time-consuming cleaning is needed for high volume manufacturing. Considerable portion of debris from Sn source can be suppressed by various debris mitigation techniques [3,4]. However, debris mitigation technique can only slow down the contamination process but will not be sufficient alone with HVM level of light production.…”

Section: Introductionmentioning

confidence: 99%

Remote plasma cleaning of Sn from an EUV collector mirror

Shin

Raju

Ruzic

2009

Alternative Lithographic Technologies

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Despite a higher conversion efficiency of Sn for extreme ultra violet (EUV) light generation at 13.5 nm, Sn contamination on collector optics in EUV source systems must be overcome before adopting Sn as EUV fuel. Considerable portion of debris from Sn source can be suppressed by various debris mitigation techniques. However, debris mitigation technique alone will not be sufficient for high volume manufacturing (HVM) scale light production. Sn contamination affects not only the light output but also cost of ownership because of costly and time-consuming cleaning or replacing. In order to solve this contamination issue, Center for Plasma Material Interactions (CPMI) at University of Illinois at Urbana-Champaign(UIUC) had been working on cleaning Sn from EUV collector mirror surface using inductively coupled plasma-reactive ion etching (ICP-RIE) method. Previously, our group showed the fast cleaning rate of >100±10 nm/min and the dependence of cleaning on plasma-source location. Atomic force microscopy (AFM) surface roughness scan after cleaning showed almost 95% recovery in root-mean-square roughness compared to beforecleaning. Sn debris contamination can also be cleaned by halogen gas at high pressure (several hundreds mTorr). However, cleaning rate is much slower so that longer cleaning time is needed and other components in the system can be harmed by high pressure of corrosive gas. In this study, a remote plasma cleaning method is newly investigated. We designed and fabricated a remote plasma cleaning system which operates with 13.56MHz RF. A residual gas analyzer is used to quantify the chlorine radicals generated in a remote plasma system. A comparative study on the chlorine radicals generated in ICP and remote plasma is carried out. The initial result with gas temperature control shows that more chlorine radicals generate by remote plasma than ICP. It is also reported that high power can produce more chlorine radicals as expected.

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