LG Innotek to slim down smartphones by replacing solder balls with copper posts

Manufacturers of smartphones are going to extreme lengths as they seek ways to make their devices more compact or install larger batteries. However, LG Innotek proposes something that looks beyond extreme: eliminating solder balls that attach chip substrates to motherboards, thereby making the innards of smartphones even thinner. Instead of solder balls, LG Innotek proposes using new Copper Posts. 

The new packaging method developed by LG Innotek places copper columns on the substrate before solder balls are applied on top, rather than bonding the balls directly to the surface. The resulting structure reduces the spacing between solder balls by approximately 20% compared to traditional layouts, while maintaining the same electrical performance. LG claims that the new method provides smartphone designers with greater flexibility in slimming down devices and increasing available space for features like batteries.

Beyond size reduction, Copper Posts potentially enable denser packaging and are a good fit for high-performance interfaces, which contributes to the features and performance of smartphones. 

The high melting point of copper ensures that the columns maintain their shape during high-temperature manufacturing steps, which enables tighter integration that was previously impractical due to the risk of solder balls merging during the soldering process. 

In addition, copper conducts heat more than seven times better than typical soldering materials, enabling excess heat from semiconductor packages to dissipate faster. This helps maintain stable performance and minimizes issues such as signal degradation caused by overheating. 

LG Innotek began working on the Copper Post technology in 2021, applying digital twin-based 3D simulation to accelerate development and improve design precision. By now, LG Innotek has secured approximately 40 patents related to its Copper Post technology. Now, the company plans to apply this technology to RF-SiP substrates (i.e., modems, power amplifiers, FRMs, filters combined into a single package) and FC-CSP (Flip Chip-Chip Scale Package for application processors) substrates for smartphones and wearables. 

"This technology is not simply about supplying components—it came from deep consideration of how to support our customers’ success," said Moon Hyuk-soo, chief executive of LG Innotek. "With this innovation, we will change the paradigm in the substrate industry and continue to create differentiated customer value."

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