| 摘要 |
PURPOSE:To enable remarkable reduction in the metal content of a resist or a smoothing agent prepared from novolak resin, by dissolving a novolak resin in a specified solvent and carrying out a liquid-liquid extraction using water from the obtd. soln. CONSTITUTION:A novolak resin is dissolved in a solvent whose solubility in water is 100 or less at 20 deg.C and liquid-liquid extraction from the obtd. soln. is carried out by using water. As the above-described solvent, acetates, ketones, alcohols, glycol ether acetates, halogenated hydrocarbons, etc., can be used. It is desirable that the concn. of the novolak soln. is about 3-50%, when dissolved in the solvent. |
