In Situ Study on Cu-to-Cu Thermal Compression Bonding
Author:
Niu Tongjun1, Xu Ke2, Shen Chao2, Sun Tianyi2, Oberst Justin3, Handwerker Carol A.2, Subbarayan Ganesh4ORCID, Wang Haiyan25ORCID, Zhang Xinghang2
Affiliation:
1. Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA 2. School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA 3. Lam Research Corporation, Tualatin, OR 97062, USA 4. School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA 5. School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA
Abstract
Cu-to-Cu thermal compression bonding (TCB) has emerged as a promising solution for ultrafine pitch packaging in 3D integrated circuit technologies. Despite the progress made by conventional Cu-to-Cu TCB methods in achieving good mechanical strength of the Cu bonds, the bonding processes generally require high temperature and high pressure, which may degrade the performance and reliability of the device. Therefore, it is imperative to investigate the processing parameters to understand the bonding mechanism and achieve effective TCB at a low temperature and low pressure. Here, we developed an in situ TCB technique inside a scanning electron microscope. The in situ TCB method enables a real-time observation of bonding development, which provides critical insights into how the texture and microstructure of Cu bumps may influence the creep and surface diffusion during the bonding process. This work features a strategy to advance our understanding of the bonding mechanisms and provides insight into tailoring the microstructure of Cu for bonding at a low temperature and low pressure.
Funder
Semiconductor Research Corporation Center for Heterogeneous Integration Research in Packaging
Subject
Inorganic Chemistry,Condensed Matter Physics,General Materials Science,General Chemical Engineering
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