FPCWAY

Research progress on polyimide FPC_1_Introduction

Introduction

Since its invention by Strong and others at DuPont in the late 1950s, polyimide has been widely researched and applied in the fields of aerospace and electronics due to its excellent thermal resistance and mechanical properties. In the aerospace field, led by NASA (National Aeronautics and Space Administration), active research has been conducted on crosslinkable thermosetting polyimides as prepregs for structural components. In the field of electronic materials, it is primarily used as an electrical insulating thin film material.

The application of polyimide in the electrical industry mainly involves the coating material for enameled wires. Since the commercialization of liquid resin Pyre ML by DuPont in the late 1960s, its use has rapidly expanded. Additionally, as a film material and molding material, Kapton films and Vespel plastics were subsequently commercialized.

In the late 1970s, with the progress of semiconductor integration, the use of polyimide in the electrical industry encountered a significant turning point, completing the transition from electrical insulating materials to electronic materials. Now, with the development of various industrial fields, especially those dominated by the electronics sector, polyimide has been applied in practice across all fields due to its high insulation, heat and cold resistance, high strength, and other reliability factors.

The reason why polyimide film is the most widely used variety of polyimide materials is closely related to its manufacturing process. Polyimide films are generally formed by reacting tetracarboxylic dianhydrides with diamines in polar solvents at room temperature and pressure to produce a polyamic acid solution. This solution is then made into a film using methods such as spin coating, followed by dehydration and cyclization using thermal or chemical methods. This aspect is the greatest advantage for its use as an electronic material. In summary, there are several reasons: ① Easy synthesis, as a variety of monomers are readily available and new materials can be easily developed using simple experimental equipment. ② Almost all forms of materials used in the electronics industry are films. ③ The water generated during the imidization process evaporates quickly due to the thinness of the film, reducing the likelihood of voids forming. ④ The transformation from polyamic acid to polyimide results in a completely different material, which allows for greater operational flexibility in multilayering processes. ⑤ No need for curing crosslinkers, etc.

This article mainly introduces the latest research progress of polyimide as a film material applied in the electrical and electronic fields, particularly in the fastest-growing flexible printed circuit boards (FPC).