Flat contacts instead of soldering will make smartphones thinner, — LG Innotek development

Developers from LG Innotek have proposed to replace solder balls that connect chip substrates with motherboards in smartphones, on flat copper contacts, which will allow make gadgets even thinner. 

Instead of soldering, LG Innotek suggests using flat copper contacts. The new method involves placing copper columns on a substrate before applying solder balls on top instead of directly attaching them to the surface.

This structure reduces the distance between the balls by about 20% compared to traditional circuits, while maintaining the same electrical performance. LG Innotek claims that their method will allow smartphone developers to reduce the size of gadgets and increase space for elements such as batteries.

In addition, copper terminals provide a denser layout and integrate well with high-performance interfaces, which can improve the functionality and performance of smartphones. Due to the high melting point of copper, these columns will retain their shape during the production stages under high temperatures. This will enable tighter integration that would not have made sense before due to the risk of solder balls merging during the soldering process. 

Copper also conducts heat more than 7 times better than conventional solder materials. This will allow for faster removal of excess heat from semiconductor packages. In turn, this will ensure better performance and minimize problems such as signal degradation due to overheating.

LG Innotek started working on Copper Post technology in 2021, using 3D modeling based on digital clones to speed up development and improve accuracy. So far, the company has already received about 40 patents for Copper Post technology.

LG Innotek wants to apply Copper Post technology to RF-SiP substrates — modems, power amplifiers, FRMs, and filters in a single package. Copper Post is also integrated into FC-CSP — Flip Chip-Chip Scale Package substrates for application processors in smartphones and wearables

Source: TomsHardware