Inorganic molecular materials such as tin oxo cages are a promising generation of photoresists compatible with the demands of the recently developed Extreme UltraViolet (EUV) lithography technology. Therefore, a detailed understanding of the photon-induced reactions which occur in photoresists after exposure is important. We used XUV broadband laser pulses in the range of 25 -40 eV from a table-top high-harmonic source to expose thin films of the tin oxo cage resist to shed light on some of the photo-induced chemistry via XUV absorption spectroscopy. During the exposure, the transmitted spectra were recorded and a noticeable absorbance decrease was observed in the resist. Dill parameters were extracted to quantify the XUV induced conversion and compared to EUV exposure results at 92 eV. Based on the absorption changes, we estimate that approximately 60% of tin-carbon bonds are cleaved at the end of the exposure.

Solid-state high harmonic generation (SSHHG) is a relatively recent, [1][2][3][4] non-destructive technique that offers new insight into the dynamics of strong-field light-matter interaction. [1][2][3][5][6][7][8] At the same time, SSHHG holds promise for being a viable route to engineering innovative, flexible, compact sources with emission in the extremeultraviolet (XUV) spectral range. 9, 10 The technique has already been shown to yield XUV light, 3, 11-13 albeit with low conversion efficiencies, as compared to the more traditional gas-based high harmonic generation (HHG) sources. 3,11 In this work we demonstrate that a non-collinear, multicolor SSHHG arrangement leads to spectra in the XUV with a high degree of tunability, and a considerable enhancement of the output flux. The observed behaviour can be understood in terms of perturbative optical wave mixing over more than one order of magnitude of the drive intensity. In addition, a model based on the recently-introduced injection current 8 allows accurate predictions over the entire experimental range.

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