Low-dielectric, nanoporous polyimide thin films prepared from block copolymer templating

Abstract

Abstract. In this paper, a new method to the preparation of low-dielectric nanoporous polyimide (PI) films was addressed, based on the self-assembly structures of PS-b-P4VP/poly(amic acid) (PAA, precursor of PI) blends. It is found the microphase-separation structure of PS-b-P4VP/PAA is a precondition of the formation of nanoporous structures, which could be achieved by solvent annealing. Nanoporous PI films with spherical pore size of ~11 nm were obtained by thermal imidization followed by the removal of the PS-b-P4VP block copolymer. The porosity of the nanoporous PI films could be controlled by the weight fraction of the PS-b-P4VP block copolymer. The dielectric properties of the nanoporous PI films were studied, and it was found that the introduction of nanopores could effectively reduce the dielectric constant from 3.60 of dense PI films to 2.41 of nanoporous PI films with a porosity of 26%, making it promising in microelectronic devices. The fabrication method described here could be extended to other polymer systems.

Insulating Property Improvement of Polyimide in Devices by Low‐Temperature Supercritical Fluids

“…This phenomenon indicates that the insulating properties of PI film have been improved after SCCO 2 treatment. To get more insight of this improvement, the main parameters including the dielectric constant of PI film and the film thickness which directly affect the leakage current were measured.…”

Fluorinated bismaleimide resin with good processability, high toughness, and outstanding dielectric properties

“…However, the thermal resistance or processing performance of BMIs is usually sacrificed with this method . The introduction of pores into a matrix material can effectively decrease ε, but it remains difficult to control the size, distribution, and content of the close pores . If too large amount of pores is introduced, the mechanical properties of the material may be remarkably decreased …”

Self-assembly of Crosslinked Polyimides Templated by Block Copolymers for Fabrication of Porous Films

“…Based on such background, the fabrication of ordered mesoporous polyimide films by the softtemplate method has been reported [19][20][21][22][23][24][25][26]. In this method, an amphiphilic block copolymer with a narrow polydispersity and a well-defined composition ratio is used as a template to form ordered microphase-separated structures.…”