Researchers realize rapid synthesis of gold microsphere array for advanced packaging

A collaborated team led by researchers from the Institute of Solid State Physics, the Hefei Institutes of Physical Science of the Chinese Acadamy of Sciences, enables the efficient construction of gold microsphere array-based anisotropic conductive adhesives film (ACF) for advanced packaging. 

The research findings were published in Nature Communications.

As electronic devices get smaller, it's becoming harder to achieve high-quality connections that are both reliable and safe from short circuits. In 2014, a Japanese company developed the array-ACF using metal-coated polymer microsphere arrays to make these connections, but the bond between the metal and polymer could crack under pressure, affecting performance.

In this study, researchers developed a new approach to fabricate pure gold microsphere arrays within 1 minute through a positioned self-assembly and laser-irradiated ripening strategy. This technique relies on a rapid layer-by-layer laser-induced melting and fusion process, effectively avoiding the anisotropic growth principle. The fundamental advantage of this strategy lies on the formed size of gold microsphere determined by the initial templating microholes and precisely positioned within them. This feature not only facilitates precise control but also ensures compatibility with lithography techniques in the industry.

The technique is also flexible and can be used to create different kinds of microspheres, including alloy microspheres made from gold and other metals. When these microspheres are treated with laser, they fuse together smoothly, creating stable and durable materials.

Compared to commercial gold-plated microspheres, the pure gold microspheres are much more flexible and resistant to electrical problems under pressure. These gold microsphere arrays could help improve the bonding of micro-displays, like those used in μLED chips, which are key to creating high-resolution displays. 

This breakthrough could have a big impact on the future of electronics and display technologies.

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