Polyisoimide as well as preparation method and application thereof

The invention discloses polyisoimide and a preparation method and application thereof.The structural formula of the polyisoimide is shown in the formula I, the dissolved solid content of the polyisoimide in a polar high-boiling-point solvent is higher than 60%, negative photosensitive polyimide compositions with different viscosities can be prepared according to different solid contents, the coating thickness range of the polyisoimide after spin coating ranges from 0.5 m to 100 m, and the thickness range of the polyisoimide after spin coating ranges from 0.5 m to 100 m. After the coating is developed and thermally cured, a negative pattern with the depth-to-width ratio larger than 2.5 and the minimum line width of 10-20 m can be realized, and the film retention rate is higher than 85%. 本发明公开了一种聚异酰亚胺及其制备方法和应用，本发明的聚异酰亚胺，其结构式如式I所示其在极性高沸点溶剂中溶解固含量高于60%，根据不同的固含量可制备不同黏度的负性光敏聚酰亚胺组合物，其旋涂后涂层厚度范围在0.5µm~100µm，涂层在经显影、热固化过程步骤后，可实现深宽比大于2.5，最小线宽为10µm~20µm的负性图案，其留膜率高于85%。