Measurement of Shear Strengths of Cu Films Using Precise Chip Forming.

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Mechanical properties of thin films are crucial but difficult to measure using conventional methods.
• Existing techniques face challenges in precisely determining intrinsic shear strength and strain.
• Understanding thin film mechanics is vital for applications in microelectronics and advanced materials.

Purpose of the Study:

• To develop and demonstrate a precise nano-cutting technique for evaluating thin film mechanical properties.
• To determine the intrinsic shear strength and shear strain of electroplated and sputtered copper (Cu) films.
• To correlate mechanical test results with structural information obtained via X-ray diffraction.

Main Methods:

• Utilized a nano-cutting technique based on an orthogonal cutting model with precise control.
• Fabricated thin films of electroplated Cu (1.5 μm and 5 μm) and sputtered Cu (130 nm).
• Performed nano-cutting experiments to measure shear strength and strain, followed by X-ray diffraction analysis.

Main Results:

• Electroplated Cu films exhibited a shear strength of ~310 MPa and shear strain of 1.57.
• Sputtered Cu film showed a higher shear strength of 389 MPa and shear strain of 2.03.
• X-ray diffraction analysis was conducted to establish correlations between film structure and mechanical behavior.

Conclusions:

• The developed nano-cutting technique effectively measures intrinsic shear properties of thin films.
• Significant differences in mechanical strength and strain were observed between electroplated and sputtered Cu films.
• The study highlights the importance of fabrication methods and structural analysis in understanding thin film mechanical properties.