1. Field of the Invention
The disclosure relates to a water-soluble, negative photoresist polymer including a salt-type repeating unit and a photoresist composition containing the same. More specifically, the disclosure relates to a negative photoresist polymer having a salt-type repeating unit, which is used with light sources such as KrF (248 nm), ArF (193 nm), and extreme ultraviolet (EUV) to form photoresist patterns, and a photoresist composition containing the photoresist polymer.
2. Description of the Related Technology
According to a conventional photolithography process for forming a photoresist pattern, a photoresist composition is applied to an underlying layer of a semiconductor substrate, and then baked to form a photoresist film. Next, the photoresist film is exposed to light and developed, and then rinsed to obtain a photoresist pattern.
The photoresist composition used in the conventional photolithography process has been oil soluble. In other words, since the photoresist polymer is oil soluble, an organic solvent, as a main solvent, has been used when a photoresist composition containing the photoresist polymer is fabricated, which results in a serious cause of environmental pollution. In addition, since a tetramethyl ammonium hydroxide (TMAH) aqueous solution or basic aqueous solution is used in the developing process, the photoresist film is required to be additionally cleaned with water in a subsequent process.