We demonstrated enhancement of in-band conversion efficiency (CE) at 13.5nm of the extreme ultraviolet (EUV) emission from a tin (Sn) cavity target irradiated by a CO2 laser pulse. Whereas a planar Sn target produced an in-band CE of around 2%, the use of cavity targets significantly enhanced the EUV emission energy and the EUV CE. An EUV CE of 4% was observed for a Sn cavity target with a depth of 200μm which is one of the highest values ever reported.
We demonstrated a fivefold reduction in Sn debris deposited on small Mo∕Si multilayer mirrors from a Sn planar target by applying a static magnetic field of 1T. The debris reduction is attributed to the decrease of more than three orders in the number of ions that reach the sample mirror due to their interaction with the applied magnetic field that guides the ions away from the mirror. The remaining deposition is due to neutral Sn atoms that do not interact with the applied magnetic field.
The 1st generation Laser-Produced Plasma source system "ETS" device for EUV lithography is under development. We report latest status of the device which consists of the original concepts (1) CO2 laser driven Sn plasma, (2) Hybrid CO2 laser system that is combination of high speed (>100kHz) short pulse oscillator and industrial cw-CO2, (3) Magnetic mitigation, and (4) Double pulse EUV plasma creation. Maximum burst on time power is 69W (100kHz, 0.7 mJ EUV power @ intermediate focus), laser-EUV conversion efficiency is 2.3%, duty cycle is 20% at maximum. Continuous operation time is so far up to 3 hours. Debris is efficiently suppressed by pre-pulse plasma formation and magnetic field mitigation system. Long-term performance is now under investigation. Also future plan is updated
We reported 1st generation Laser-Produced Plasma source system "ETS" device for EUV lithography one year ago 1) . In this paper we update performance status of the 1st generation system. We have improved the system further, maximum burst power is 104W (100kHz, 1 mJ EUV power @ intermediate focus), laser-EUV conversion efficiency is 2.5%. Also continuous operation time is so far up to 8 hours with 5% duty cycle is achieved. We have investigated EUV plasma creation scheme by small experimental device which is facilitated 10Hz operation (maximum). We have proposed double pulse method to create LPP plasma efficiently. This moment we found out 3.3% conversion efficiency operation condition.Based on the engineering data of ETS and small experimental device, now we are developing 2 nd generation HVM source; GL200E. The device consists of the original concepts (1) CO 2 laser driven Sn plasma, (2) Hybrid CO 2 laser system that is combination of high speed (>100kHz) short pulse oscillator and industrial cw-CO 2 , (3) Magnetic mitigation, and (4) Double pulse EUV plasma creation. The preliminary data are introduced in this paper.
We develop a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography. The light source is based on a short pulse, high power, high repetition rate CO 2 master oscillator power amplifier (MOPA) laser system and a Tin droplet target. A maximum conversion efficiency of 4.5% was measured for a CO 2 laser driven Sn plasma having a narrow spectrum at 13.5 nm. In addition, low debris generation was observed. The CO 2 MOPA laser system is based on commercial high power cw CO 2 lasers. We achieve an average laser power of 6 kW at 100 kHz with a single laser beam that has very good beam quality. In a first step, a 50-W light source is developing. Based on a 10-kW CO 2 laser this light source is scalable to more than 100 W EUV in-band power.
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