Localized Induction Heating of Cu-Sn Layers for Rapid Solid-Liquid Interdiffusion Bonding Based on Miniaturized...

Area of Science:

• Materials Science and Engineering
• Microelectronics
• Nanotechnology

Background:

• Low-temperature bonding is crucial for 3D integration and microelectronic packaging.
• Conventional methods often lack the speed and precision required for chip-level applications.

Purpose of the Study:

• To develop and apply an innovative inductive heating system using micro coils for rapid chip-level Cu-Sn SLID bonding.
• To optimize micro coil design and analyze the heating process for efficient bonding.

Main Methods:

• Finite Element Method (FEM) for micro coil design and heating process analysis.
• Fabrication of micro coils using electroplating of copper onto an aluminum nitride (AlN) substrate.
• Implementation of inductive heating for Cu-Sn SLID bonding at the chip level.

Main Results:

• Achieved complete transformation to the stable ε-phase Cu₃Sn in 130 seconds with 3 MPa bond pressure.
• Obtained an average shear strength of 45.1 N/mm² for the Cu-Sn SLID bonds.
• Demonstrated high heating rates (~180 K/s), localized heating, and efficient cooling.

Conclusions:

• The developed inductive bonding system offers a rapid and effective solution for low-temperature chip-level interconnects.
• This technology holds significant potential for advancing wafer-level bonding in microelectronics and micromechanics.
• The approach overcomes limitations of conventional global heating methods by providing precise thermal control.