Research Of Diamond Composites For Electronic Packaging

Owing to the excellent performance,diamond composite is becoming one of the most potential materials in electronic packaging field.The purpose of this work is to prepare diamond composites with excellent comprehensive performance at low temperatures.In this article,the diamond composites were prepared by the combination of diamond and glass with low melting points.The effects of sintering temperature,additives and sintering process on the properties of glass and diamond composites were systematically studied.The results indicated that 780°C was the optimal sintering temperature of diamond/glass composites under pressureless sintering process.Among the six kinds of additives,CeO₂/Y₂O₃ and CeO₂/Y₂O₃/Ti had the most notable influence on the properties of glass and diamond composites,followed by CeO₂,CeO₂/Ti,Y₂O₃,and Ti.In general,with the increase of additives contents,the refractoriness of the glass decreased firstly and then increased,whereas the fluidity changed inversely.When the content of CeO₂/Y₂O₃?mass fraction ratio 1:1?was 4 wt.%,the composite had a maximum bending strength of 108.56 MPa.When adding 4 wt.%CeO₂/Y₂O₃ and 2wt.%Ti,the composite had the highest thermal conductivity of 4.78 W/?m·k?.In addition,the results showed that the dielectric constant of the diamond composites decreased with increasing additives contents.The dielectric constants of the diamond composites were between 7 and 14 at 1 KHz.While the test frequency was 1 MHz,the dielectric constants of diamond composites were between 3 and 7.It could be found that the additives contributed to the decrease of the coefficient of thermal expansion of composites.The thermal expansion coefficients of diamond composites were in the range of?3.7-4.1?×10^-6/?,which was in good agreement with the Si devices and met the requirements of electronic packaging.Among the four sintering methods?hot-pressed sintering,spark plasma sintering,atmosphere sintering and pressureless sintering?,the composites prepared by hot-pressed sintering had the most compact structures and highest thermal performance of 18.17 W/?m·k?,while they showed the highest dielectric constants.