Scheme for Multi-Chiplet Integration With Low Thermal Budget by Asymmetric Cu-Cu Bonding With Au Passivation Bonding Structure
Zhong-Jie Hong, Ming-Wei Weng, Chih-Han Chen, Mu-Ping Hsu, Hanwen Hu, Tai‐Yu Lin, Ying-Chan Hung, Kuan‐Neng Chen
Abstract
This study proposed a multi-chiplet integration scheme using Cu–Cu bonding with a low thermal budget by utilizing an asymmetric passivation bonding structure. The single-sided passivation structure was achieved through one-sided heating thermal compression bonding at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150~^{\circ }\text{C}$ </tex-math></inline-formula> ; the bonding quality was enhanced by the passivation layer with small grain size. The bonding interface of the single-sided passivation structure was analyzed through transmission electron microscope, and the corresponding mechanism was inferred. Compared with original passivation structures, the single-sided passivation structure not only enhanced bonding quality but also provided higher bonding strength, and the contact resistance was lower than Cu-Cu direct bonding. Therefore, the single-sided passivation structure with low thermal budget, high bonding strength and high throughput can be applied to multi-chiplet integration.