Effect of polymer modification on microwave digestion efficiency, thermal stability and plasma etching resistance for the photoresist

The UV/VIS spectrometric and gravimetric methods were successfully implemented to evaluate the open-focused microwave digestion efficiency for a photoresist sample after modification with poly(4-hydroxystyrene) polymer. The polymer modification can slightly degrade the digestion efficiency for the photoresist. By following the established microwave digestion method and inductively coupled plasma mass spectrometry determination, the detection limits obtained for multi-elements were in the ng ml^-1 and sub-ng ml^-1 levels. Except for calcium, the spike recoveries of the metals were in the range 88-128% for the modified sample. The analytical results were found to be in reasonably good agreement with the literature values. The mass losses of the modified photoresists appeared at three major decomposition temperatures (138-142, 344-357 and 471-509°C), irrespective of the amounts of modification. The modification can enhance the thermal stability, viscosity and plasma etching resistance for the photoresist. Our results demonstrated that the polymer structure of the photoresist is still similar regardless of the modification.