Synthesis Of Alkali-soluble Photosensitive Prepolymers And Application In Negative Photoresist

In microelectronics industry, photolithography is a common process used in semiconductor manufacturing of integrated circuit at present. Thus, developing certain photoresists which possess specific functions and can be applied to industrial production is crucial. However, conventional negative photoresists which contain heavy metals is gradually replaced by new types of photoresists due to the serious pollution to the environment.In this thesis, a series of ultraviolet (UV)-curable and alkali-soluble prepolymers were synthesized by esterification of OH groups of Hydroxyethyl acrylate(HEA) with different types of anhydrides. The esterification conditions were studied by titration of acid value and FT-IR. Anhydride was added in HEA with triphenylphosphine(TP) as catalyst and4-metoxyphenol(MEHQ) as inhibitor, and then heated to90℃and kept for3hours. The results showed that when the molar ratio of HEA to anhydride is1:0.75, the dosages TP and MEHQ are1wt%and0.1wt%respectively, and anhydrides were added in several steps in80℃, the optimal synthetic conditions were obtained. Therefore, the conversion of HEA esterified by hexahydrophthalic anhydride (HHPA) could reach86.13%with viscosity of3710CP.What’s more, various UV curing system were prepared by adding photoinitiators to these prepolymers, and then cured by UV-curing apparatus. The properties such as surface hardness, adhesive force, acid proof and membrane stripping performance in alkali aqueous solution were studied. Furthermore, the conversion of double bonds and thermal property of cured film were investigated by IR and TG-DSC respectively. Among them, UV curing conversion of prepolymer(HHPAHEA) prepared by HEA and HHPA can reach94.47%after exposure for24seconds, the weight loss of cured film is1.5%from room temperature to125℃.In terms of the synthesis and curing performance of prepolymers, HHPAHEA is selected as the main resin, then grinded with photoinitiators, packing, pigments and other additives in three-rollers machine, a new type of negative photoresist was prepared. By means of UV absorption spectra, laser particle size analyzer and optical microscopy, the properties of cured film and performances of curing and screen printing were studied. The results showed that Irgacure907/ITX or Darocue1173is suitable photoinitiator for this photoresist due to their good compatibility and high initiating efficiency in formulation; BaSO4with a dosage below50wt%can improve the surface hardness and adhesive force of cured film; In the presence of0.5wt%fumed silica, the surface hardness of cured film increases from3B to H, and adhesive force is improved from level5to level0, the screen printing performance become better as well. In addition, the oxygen inhibition during UV curing is investigated by ATR-FTIR, the results indicated that it is desirable to solve this problem by increasing the amount of photoinitiator Darocue1173to8wt%, and the conversion of double bonds can achieve96.02%in surface layer.