Reactive wafer bonding with nanoscale Ag/Cu multilayers. (15th July 2020)

• Record Type: Journal Article
• Authors: Liu, Yu-chen; Lin, Shih-kang; Zhang, Hao; Nagao, Shijo; Chen, Chuantong; Suganuma, Katsuaki
• Is Part Of: Scripta materialia. Number 184(2020)
• Page Start: 1
• Page End: 5
• Publication Date: 2020-07-15
• Subjects: Reactive bonding -- Ag-Cu-O -- Wafer bonding -- CALPHAD; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2020.03.043
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Reactive bonding using nanoscale multilayers based on the high specific surface/interface energy is a promising low-temperature and low-pressure wafer-bonding process. Herein, Si wafers were bonded using nanoscale Ag/Cu multilayers in N2 or the ambient atmosphere. A flawless joint composed of Ag-rich and Cu-rich face-centered cubic (fcc) phases was achieved in N2 with 22.2 MPa shear strength. However, a peculiar "fcc-(Ag)+voids/Cu2 O/fcc-(Ag)+voids" three-layer sandwich structure with 11.1 MPa shear strength was formed due to significant out segregation of Cu toward the bonding-interface in the ambient atmosphere. The bonding mechanism and the role of oxygen were unveiled based on CALPHAD (CALculation-of-PHAse-Diagram) thermodynamic modeling. Graphical abstract: Image, graphical abstract