Dependence of dose rate on the sensitivity of the resist under ultra-high flux extreme ultraviolet (EUV) pulse irradiation

Efforts are being focused on increasing the power of extreme ultraviolet (EUV) light sources used in semiconductor manufacturing to increase the throughput. As a result, the investigation of the effect of high power sources on resist materials is a critical issue. A chemically amplified resist (CAR) and a non-CAR were irradiated with 13.5 nm EUV high-flux pulses from a soft X-ray free-electron laser (FEL). In the non-CAR, the positive-tone resist (ZEP520A) exhibited lower sensitivity at high irradiation densities, while the negative-tone resist exhibited a higher sensitivity. In addition, the dose rate did not considerably affect the sensitivity of the CAR.