Fabrication of Functionally Graded Diamond/Al Composites by Liquid-Solid Separation Technology

Area of Science:

• Materials Science
• Mechanical Engineering
• Electronics Packaging

Background:

• Traditional electronic packaging shells lack position-specific material properties required for optimal performance.
• Mechanical processing of uniform blocks results in shells with uniform properties, failing to meet diverse functional demands.
• Hermetic packaging of large microelectronic devices necessitates advanced materials for shells.

Purpose of the Study:

• To develop a method for fabricating electronic packaging shells with graded material properties.
• To address the challenge of meeting varied performance requirements at different shell locations.
• To improve the thermal stability and reliability of microelectronic packaging components.

Main Methods:

• Application of an independently developed liquid-solid separation technology.
• Fabrication of diamond/aluminum (Al) composites with a gradient distribution of diamond particles.
• Characterization of interfacial properties and material performance metrics (thermal conductivity, coefficient of thermal expansion, bending strength).

Main Results:

• Achieved a graded distribution of diamond particles in diamond/Al composites, decreasing from 48 vol.% at the bottom to 15 vol.% at the top.
• The bottom of the shell exhibits high thermal conductivity (169 W/mK) and lower bending strength (88 MPa), suitable for chip housing.
• The top of the shell shows lower thermal conductivity (108 W/mK) but higher bending strength (175 MPa), ideal for cover plate welding.

Conclusions:

• The developed liquid-solid separation technology enables near-net shape forming of packaging shells with tailored, graded properties.
• The graded diamond/Al composites effectively meet the special requirements of different shell sections, enhancing thermal stability.
• This approach offers a promising solution for advanced electronic packaging material fabrication.