The invention provides a novel sulfonium salt having at least one acid labile group attached to a phenyl group in a molecule and a C.sub.2 -C.sub.20 alkylsulfonate or arylsulfonate anion whose alkyl or aryl has as a substituent an electron withdrawing group such as fluorine and nitro group. The novel sulfonium salt is effective for increasing the dissolution contrast between exposed and unexposed areas. Upon exposure, it generates a substituted alkyl or arylsulfonic acid which is a weak acid, minimizing the influence of side reaction and deactivation during PEB step. The sulfonium salt is useful in a chemically amplified positive resist composition which lends itself to fine patterning and features high resolution.
本发明提供了一种新型的磺鎵盐,其分子中至少有一个酸敏感基团连接到苯基上,以及一种C.sub.2-C.sub.20的烷基
磺酸盐或芳基
磺酸盐阴离子,其烷基或芳基具有电子吸引基团,例如
氟和硝基作为取代基。新型磺鎵盐对于增加暴露区域和未暴露区域之间的溶解度对比是有效的。在曝光后,它会产生一种取代的烷基或芳基
磺酸,这是一种弱酸,可以最小化PEB步骤中的副反应和失活的影响。该磺鎵盐在
化学增感正性光刻胶组成中非常有用,适用于精细图案和高分辨率。