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The modification of the i-line resist structure after spiking with various amount of poly(4-vmylphenol) polymer is characterized by the spectra of ultraviolet visible (UV-VIS) and gel permeation chromatography (GPC). The chemical structure of photoactive compound is found to be unchanged after modification, while slight change in the polymer chain is obserbed. The resist layer coated onto the wafer is characterized by various methods including n&k analyzer, Nanospec, Fourier transform infrared red (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to fully evaluate the film properties in terms of porosity, thickness, vibrational spectrum, and thermal stability. Our thermal analysis results show that the resists are mainly decomposed in three stages. The photoactive compound (PAC) is found to decompose during the first stage, while the polymer decomposes during the latter stages. The resist exposure parameters, namely, A, B and C at 365 nm are determined by the absorbance measurement. The extracted parameters are further used in the resist profile simulation by PROLITHI2. It is shown that the spiking of poly(4-vinylphenol) polymer into the resist can improve the resolution and linearity for dense lines. In addition, the swing effects can be reduced by up to 35 and 3 1 % for dense and isolated lines after resist modification, respectively.

The UV/VIS spectrometric and gravimetric methods were successfully implemented to evaluate the openfocused microwave digestion ef®ciency for a photoresist sample after modi®cation with poly(4-hydroxystyrene) polymer. The polymer modi®cation can slightly degrade the digestion ef®ciency 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 21 and sub-ng ml 21 levels. Except for calcium, the spike recoveries of the metals were in the range 88±128% for the modi®ed sample. The analytical results were found to be in reasonably good agreement with the literature values. The mass losses of the modi®ed photoresists appeared at three major decomposition temperatures (138±142, 344±357 and 471± 509 ³C), irrespective of the amounts of modi®cation. The modi®cation 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 modi®cation.