The Preparation of High-Volume Fraction SiC/Al Composites with High Thermal Conductivity by Vacuum Pressure Infiltration

Mengqin Chen,Zhifeng Zhang,Yuelong Bai,Haidong Zhao

doi:10.3390/cryst11050515

Abstract

The high-volume fraction SiC/Al composite is the new type of electronic packaging material, which plays an important role in the field of high-power integrated circuits. In this study, SiC/Al composites with high-volume fraction of SiC particles were prepared by vacuum pressure infiltration. The influence of SiC particle size and NH4HCO3 on the pores in the preform was explored, aiming to accurately adjust the volume fraction of SiC to meet the thermal performance requirements in different fields. In addition, the preform was infiltrated with different Al alloys, and the relationship between the porosity and thermal conductivity of SiC/Al was studied. For the SiC preform, the volume fraction of SiC can be adjusted regularly when 12 μm and 100 μm SiC particles are mixed in different proportions, and the volume fraction reaches the maximum when the proportion of coarse particles is about 77%. NH4HCO3 is conducive to the connectivity of pores in the preform, and about 40 vol.% of NH4HCO3 can effectively increase the porosity of the preform. Thermal conductivity is sensitive to the porosity of composites, especially in the range of 2.5–4.5%. A simple application of the Hasselman–Johnson model and a new thermal conductivity model, λd, established in this article, offer a good agreement with the experimental results.

Highlights

With the rapid development of electronic science and technology, the high integration of chips and the miniaturization of packaging put forward higher requirements for electronic packaging materials [1]
It is considered that the apparent volume of the preform after sintering is the volume formed by SiC particles and pores, that is, SiC
The volume fraction of SiC can be adjusted from 56% to 68% when SiC particles with bimodal size are mixed in different proportions

Summary

Introduction

With the rapid development of electronic science and technology, the high integration of chips and the miniaturization of packaging put forward higher requirements for electronic packaging materials [1]. High-volume fraction SiC/Al composites (the volume fraction of SiC is more than 50 vol.%) have attracted much attention in the field of aerospace, rail transit, automobile, and other high-power integrated circuits, which need fast heat dissipation and matching expansion coefficient, due to their excellent thermal conductivity, low expansion coefficient, low density, and designability [2,3]. Many previous works have focused on the preparation of SiC/Al composites with low volume fraction, and the preparation of high-volume fraction composites containing more than 50 vol.% SiC particles have not been fully studied. It is necessary to explore a near net forming technology for the composites [4,5]. Compared with powder metallurgy and the stirring casting method [6,7], the vacuum pressure infiltration method has characteristics including short infiltration time, near net shape, and

Methods

Results

Conclusion