KAIST Researchers Develop Anisotropic Conductive Film That Improves Ultra-Fine Pitch Assemblies In High-Res Display

KAIST Anisotropic Conductive Film for High Resolution Display
Proto-type production of APL ACFs. (Photo credit: KAIST)

Higher resolution display electronic devices increasingly needs ultra-fine pitch assemblies. On that account, display driver interconnection technology has become a major challenge for upscaling display electronics.

Read more Plastic Logic’s New Flexible Color Display Set To Revolutionize Wearables

Researchers have moved one step closer to realizing ultra-fine resolution for displays with a novel thermoplastic anchoring polymer layer (APL) structure. This new structure can significantly improve the ultra-fine pitch interconnection by effectively suppressing the movement of conductive particles. This film is expected to be applied to various mobile devices, large-sized OLED panels, and VR, among others, reports KAIST.

A research team under Professor Kyung-Wook Paik in the Department of Materials developed an anchoring polymer layer structure that can effectively suppress the movement of conductive particles during the bonding process of the anisotropic conductive films (ACFs). The new structure will significantly improve the conductive particle capture rate, addressing electrical short problems in the ultra-fine pitch assembly process.

During the ultra-fine pitch bonding process, the conductive particles of conventional ACFs agglomerate between bumps and cause electrical short circuits. To overcome the electrical shortage problem caused by the free movement of conductive particles, higher tensile strength anchoring polymer layers incorporated with conductive particles were introduced into the ACFs to effectively prevent conductive particle movement.

Two researchers
Professor Paik (right) and PhD Candidate Yoon (Photo credit: KAIST)

The team used nylon to produce a single layer film with well-distributed and incorporated conductive particles. The higher tensile strength of nylon completely suppressed the movement of conductive particles, raising the capture rate of conductive particles from 33% of the conventional ACFs to 90%. The nylon films showed no short circuit problem during the Chip on Glass assembly. Even more, they obtained excellent electrical conductivity, high reliability, and low cost ACFs during the ultra-fine pitch applications.

Read more TCL Readies Its Wearable Display, Will Be Available Later This Year

Professor Paik believes this new type of ACFs can further be applied not only to VR, 4K and 8K UHD display products, but also to large-size OLED panels and mobile devices.

His team completed a prototype of the film supported by the ‘H&S High-Tech,’ a domestic company and the ‘Innopolis Foundation.’ The study, whose first author is PhD candidate Dal-Jin Yoon, is described in the October issue of IEEE TCPMT.

Previous articleDesigning Flexible and Rigid Medical Wearables To Withstand Everyday Wear-and-Tear
Next articleSamsung’s LPDDR5 UFS-Based Multichip Package Delivers Highest Performance To Make 5G Accessible To Smartphone Users
Sam Draper () is Online Editor at WT | Wearable Technologies specialized in the field of sports and fitness but also passionated about any new lifestyle gadget on the market. Sam can be contacted at press(at)wearable-technologies.com.