Gigaphoton, a provider of lithography light sources, has declared its new extreme ultraviolet (EUV) conversion efficiency (CE) results.
According to the data, Gigaphoton has achieved 5.2% conversion efficiency with an average value of 4.7%, while generating EUV energy using tin plasma. The industry target set for the first generation, production EUV scanner is 5% CE. As per the company, it has achieved unprecedented CE results for a second time using its proprietary pre-pulse laser technique, representing a significant progress in developing a high-power light source that runs at a low cost for mass production.
Gigaphoton's proprietary design enables the laser-produced plasma (LPP) light source to emit maximum EUV energy from the tin plasma. At first, a short-wavelength, solid state laser is used as a pre-pulse to irradiate a tin droplet and then the main-pulse CO2 laser is used to irradiate the enlarged droplet. The optimum 5.2% CE was a result of the use of 150 mJ CO2 laser energy, which may be equal to a EUV output of 175 W at a CO2 laser frequency of 100 kHz.
Since 2002, Gigaphoton has been advancing LPP light sources for use in EUV lithography with novel technologies to achieve better CoO and higher output. The company has recommended several innovative solutions, which include on-demand supply of below 20-µm-diameter tin target droplets, an optimal combination of the main CO2 laser pulse and short-wavelength solid state laser pre-pulse, and protection of collector mirror by mitigating and removing debris utilizing magnetic fields. The record production-level CE is a key milestone towards the first delivery of a mass production model.