Optimization of Novolak Resin Materials and Processes

A detailed explanation of the old yet new "Novolak resin," which is still widely used.

Semiconductors and liquid crystal devices are manufactured by repeating the lithography process multiple times. During these dozens of repetitions, the need for cutting-edge fine patterns is limited to a few processes, such as the gate process, while the majority uses thicker line width patterns. Novolak resist is used for these thick patterns. Of course, depending on the device, chemical amplification resist for KrF (248 nm) may also be used here. Therefore, in semiconductor devices, while not all processes use thick line widths, novolak resist is still used, and in considerable amounts. Additionally, in emerging countries like China, semiconductor device manufacturing involves producing older generation devices, where novolak resist is naturally used. Furthermore, in liquid crystal manufacturing, novolak resist is used in all processes (5 processes). There seem to be device manufacturers that use 4 processes due to the use of halftone masks. The introduction of chemical amplification resist, which is high sensitivity and high resolution, is also being considered, but practical application has not been achieved due to the significantly larger substrate sizes compared to semiconductors and the difficulty in controlling the usage environment.

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