Four New Application Areas for Electronic Grade PI Materials

Polyimide film is the world's leading film insulation material, known in the industry as the "golden film". Today, PI films are used in a wide range of applications, including flexible displays, FPC, 5G cell phones, semiconductor packaging, and more. As the market demand for electronic-grade PI film continues to grow, it has also given rise to new application areas.

1. Flexible substrate

• Along with OLED to replace LCD is along the surface → foldable → curly direction, organic light-emitting materials and film is OLED to achieve the key point of flexibility, with excellent high-temperature characteristics, mechanical properties and chemical stability of polyimide PI substrate, is the current best choice of flexible substrate materials. Benefit from the continuous growth of OLED production capacity, PI substrate materials have a strong market demand, and there is a lot of room for growth in the future.

2. Cover Material

• In order to fully realize flexible display, the display cover part should be repeatedly bendable, transparent, ultra-thin, and sufficiently hard. Folding screens have higher requirements for cover materials, which need to meet their flexibility, light transmittance and good surface scratch resistance. The current folding screen cover materials include CPI, PI, PC, acrylic and PET, among which, CPI cover is the most feasible. The colorless and transparent CPI cover has a higher light transmittance than the common light yellow PI cover material. Benefiting from the development of folding screen cell phones, CPI cover materials will usher in a period of rapid development.

3. COF Materials

• COF solutions mainly use polyimide (PI film) mixture materials, the thickness of only 50-100um, line width line spacing below 20um.COF package is produced using automated roll-to-roll equipment, the production process will be continuously heated to 400 degrees Celsius. Since the COF roll-to-roll production process requires heating, and the coefficient of thermal expansion of the PI film is 16um/m/C, compared to the chip's 2.49um/m/C, the thermal stability is poor, so the equipment precision and process requirements are very high.

4. FPC: Substrate and cover layer materials

• The use of FPC is generally made of copper foil laminated with PI film material to make a flexible copper-clad substrate (FCCL), cover film (Coverlayer), reinforcing boards and anti-static layer and other materials made into a flexible board. The thickness of PI film can be distinguished as 0.5mil, 1mil, 2mil, 3mil and thick film (even more than 10mil, etc.), advanced or high-level flexible boards require a thinner thickness (0.3mil), dimensional stability and more stable PI film. The general covering film mainly uses PI film with a thickness of 0.5 mil, while the thicker PI film is mainly used for reinforcing boards and other applications.