Low Sintering Temperature Nano-Silver Pastes with High Bonding Strength by Adding Silver 2-Ethylhexanoate

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Developing low-temperature bonding materials is crucial for flexible electronics and semiconductor packaging.
• Traditional conductive pastes often require high sintering temperatures, limiting substrate compatibility.
• Nano-silver pastes offer potential for lower processing temperatures and improved conductivity.

Purpose of the Study:

• To synthesize and characterize a novel low sintering temperature nano-silver paste (PM03).
• To optimize the formulation and processing conditions for enhanced bonding performance.
• To investigate the structure-property relationships in the nano-silver paste.

Main Methods:

• Synthesis of silver 2-ethylhexanoate precursor and silver nanoparticles.
• Formulation of nano-silver paste (PM03) with varying silver precursor content.
• Optimization of thermal compression parameters (temperature, pressure, time) for copper-to-copper bonding.
• Microstructural analysis (e.g., porosity) and property evaluation (resistivity, shear strength).

Main Results:

• The addition of silver 2-ethylhexanoate significantly reduced paste porosity.
• Optimized paste (PM03) achieved a resistivity of (3.50 ± 0.02) × 10^-7 Ω∙m.
• Optimal bonding conditions (250 °C, 10 MPa, 30 min) yielded a shear strength of 57.48 MPa.
• Reduced porosity correlated with lower electrical resistivity and higher shear strength.

Conclusions:

• The developed nano-silver paste (PM03) enables effective low-temperature copper-to-copper bonding.
• Silver 2-ethylhexanoate plays a key role in enhancing the paste's microstructure and bonding properties.
• The optimized paste demonstrates potential for applications requiring high conductivity and mechanical integrity at reduced processing temperatures.