Acid generator and thin film composition containing the same

The present invention relates to the compounds generating strong acids (described hereafter as “acid generators”) decomposed by heat and the composition of thin film containing the same. Provided are the compounds represented by the structure of formula I and the composition containing the compounds. wherein X is alkyl or aryl group and R is hydrogen atom, hydroxy, alkoxy or alkyl group. The abovementioned acid generators of the present invention generate acid by heat at relatively low temperatures, preventing the change in the ratio of the composition due to evaporation of some components in the composition. Accordingly, it has the advantageous effect that the ratio of components in the composition is controlled and the preparation of the thin film with the wanted properties is simplified.