Dissolution dynamics of partially protected poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solution

Abstract

A 0.26 M tetramethylammonium hydroxide (TMAH) aqueous solution has been used as a standard developer for manufacturing semiconductor devices. Alternative developers have recently attracted much attention because the 0.26 M TMAH developer may be approaching its performance limit. In this study, we measured the dissolution and swelling behavior of resist polymers in tetraalkylammonium hydroxide (TAAH) aqueous solutions using a quartz crystal microbalance method to clarify the effects of the alkyl chain length of TAAH. The resist polymer was poly(4-hydroxystyrene), whose hydroxyl groups were partially protected with t-butoxycarbonyl groups. When the alkyl chain length of TAAH was increased from two (ethyl) to three (propyl), the dissolution mode markedly changed. The dissolution mode did not depend on the polymer polarity. The change of the dissolution mode is probably caused by the size effect of TAAH, considering the independence of polymer polarity and the discrete change of the dissolution mode.

Sensitization of polymethacrylate resist with adding acid-generating promoters upon exposure to EUV light

“…In particular, the dissolution properties of polymers in developer solutions have been studied extensively. Thus far, the dissolution properties of KrF, 43,46) ArF, [46][47][48] EB resists, 49,50) and EUV resists and model polymers [51][52][53][54][55][56][57][58] during development have been studied with the advancement of lithographic technology. The resist sensitivity can be determined from whether the initial film elutes into the developer or remains undissolved in the development process when the exposure dose is changed.…”

Effects of photoacid generator decomposition on dissolution kinetics of poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

“…This is characteristic of the PHS matrix. 36) The dissolution rate of PHS films increased with UV irradiation for the TMAH and TEAH developers, whereas the dissolution time increased for the TBAH developer with UV irradiation. For the TProAH developer, the dissolution time of PHS films without PEB slightly decreased.…”

Classification of dissolution modes of partially protected poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

“…[13][14][15][16][17][18] In our previous research, we examined the dissolution and swelling behavior of partially protected PHS in tetraalkylammonium hydroxide (TAAH) aqueous solutions using the quartz crystal microbalance (QCM) method. 19) The dissolution mode changed as the alkyl chain length of TAAH increased from two to three. This dissolution mode change was attributed mainly to the effect of the size of TAAH molecules rather than the polarity of the polymer.…”

“…The materials used were the same as those used in our previous study 19) with the addition of PHS with the protection ratios of 25, 35, and 40 mol%. In this study, a polymer with a x mol% protection ratio is called PRx (e.g.…”