EUV sources for EUV lithography in alpha-, beta-, and high volume chip manufacturing: an update on GDPP and LPP technology

Abstract

In the paper we report about the progress made at XTREME technologies in the development of EUV sources based on gas discharge produced plasma (GDPP) technologies and laser produced plasma (LPP) technologies.First prototype xenon GDPP sources of the type XTS 13-35 based on the Z-pinch principle with 35 W power in 2π sr have been integrated into micro-exposure tools from Exitech, UK. Specifications of the EUV sources and experience of integration as well as data about component and optics lifetime are presented.In the source development program for Beta exposure tools and high volume manufacturing exposure tools both tin and xenon have been investigated as fuel for the EUV sources. Development progress in porous metal cooling technology as well as pulsed power circuit design has led to GDPP sources with xenon fuel continuous operating with an output power of 200 W in 2π sr at 4500 Hz repetition rate. With tin fuel an output power of 400 W in 2π sr was obtained leaving all other conditions unaltered with respect to the xenon based source. The performance of the xenon fueled sources is sufficiently good to fulfill all requirements up to the beta tool level.For both the xenon and the tin GDPP sources detailed data about source performance are reported, including component lifetime and optics lifetime. The status of the integration of the sources with grazing incidence collector optics is discussed. Theoretical estimations of collection efficiencies are compared with experimental data to determine the loss mechanisms in the beam path. Specifically contamination issues related to tin as target material as well as debris mitigation in tin sources is addressed.As driver lasers for the LPP source research diode-pumped Nd:YAG lasers have been used to generate EUV emitting plasma. As target material xenon has been employed. Conversion efficiencies have been measured and currently the maximum conversion efficiency amounts to 1 %. The laser driver power of 1.2 kW is currently achieved with a masteroscillator power-amplifier industrial Nd:YAG laser configuration. With this laser, xenon based EUV sources have achieved 10 W EUV power at 13.5 nm emitted into 2π sr solid angle.For the xenon LPP sources detailed data about the achieved source performance including component lifetime and optics lifetime are reported. The status of the integration of the sources with normal incidence collector optics is shown.The potentials and limits of Z-pinch GDPP and LPP EUV source technologies to achieve high volume manufacturing specifications are discussed in this paper.

EUV generation using a droplet of a suspension including tin as a target of a high-efficiency LPP source for high volume production

“…In spite of our pushing a Sn LPP for many years, regrettably, there was no progress in LPP power after a report of 22 W into 2π sr by CEO in 2,003 [5]. However, this stagnation of LPP power was what we anticipated at that time because we did not hear new proposals of target delivery.…”

“…As seen in the above discussion, the plasma is required to have the opacity τ opa larger than 0.5 for the power P IF larger than 100 W. There is a report [14] that calculated transition cross section of radiation of a Sn plasma at the peak emission is σ(ν)=2E-17cm 2 for Sn at13-14nm ---- (5).…”

“…Presently, however, all suppliers have switched to Sn from Xe. They report EUV power from a Sn fuel more than two times that available by a Xe fuel [5]. Now, 5 years after our first pushing Sn, no person would argue against our claim on the necessity of a Sn fuel.…”

Next-generation lithography for 22 and 16 nm technology nodes and beyond

“…This corresponds to an IF power of 2.3 W and CE of 1% [22]. In following year, 1.2 kW laser power LPP with xenon target produced 10 W EUV power at 2% bandwidth, and 3.3 W IF power with a CE of 1% [39].…”

“…In 2005, a DPP EUV source produced 200 W of EUV radiation at a 2π sr solid angle with an IF power of 25.7 W (CE = 1.0%) using xenon, and a 400 W EUV 2π sr (CE = 2.0%) with 51.4 IF power using tin [39]. In the following year, 800 W in 2π sr from a tin DPP EUV source in burst operation, corresponding to 70-120 W IF power was reported, but the required electrode lifetimes could not meet [40].…”