A color-coded light-induced heating technology for Pb-free solder joints of advanced multi-semiconductor packaging

초록

The complexity of semiconductor packaging is increasing due to artificial intelligence, heterogeneous integration, and chiplet technology, necessitating precise thermal control in multi-component soldering. Conventional reflow soldering requires multiple heating cycles to accommodate different solder alloys, leading to process inefficiencies, excessive thermal exposure, and mechanical degradation. This study introduces a color-coded intense pulsed light (IPL) reflow process, leveraging differential light absorption for localized thermal modulation, enabling simultaneous soldering of multiple alloys in a single reflow cycle. The results show that IPL-soldered joints exhibit superior or comparable mechanical integrity to conventional reflow, with thinner, more stable intermetallic compound (IMC) layers, refined Ag3Sn precipitates, and reduced void formation, enhancing reliability. The rapid, transient heating of IPL suppresses excessive IMC growth while optimizing microstructural evolution. Substrate color engineering offers a scalable method for selective thermal regulation, positioning color-coded IPL as a high-efficiency, energy-conscious alternative for next-generation semiconductor packaging.

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