Study On Diamond/Cu Composites Fabricated By Pressureless Infiltration Method

With the development of microelectronic technology,thermal management of electronic devices play a important role.However,the traditional packaging materials can not meet the requirements for development of microelectronic devices.It is therefore necessary to search a new type of material for heat sink with high thermal conductivity,as well as matching the linear expansion coefficient of the base material.This study focused on the Diamond/Cu composites materials,including the following aspects.The research results of salt-bath plating tungsten are listed as follow:Plating temperature of 1150?and plating time of 30min,The morphology of the diamond coating are shown to be composed of continuous particles.The phase of coating contain W₂C.Diamond/Cu composites are prepared by pressureless infiltration method,using the coated diamond as a filler,its thermal conductivity up to 461 W×m^-1×K^-1,a fine tightness(7.3?10^-10Pa×m³×s^-1).After diamond surface was modified by different sputtering with the value of coating thickness 300nm,the composition and structure of the coating are investigated using scanning electron microscopy?SEM?,x-ray diffraction.and the following heat-treatment is implemented to improve the surface morphology of W coating.The results indicated that W coating be deposited on the surface of diamond particles by direct current magnetron sputtering method,the coating thickness was about 300nm.After 800?and 700?heat-treatment for 2h,the phase of coating is W.after 980?heat-treatment for 2h,the phase of tungsten coating is W-W₂C-WC,respectively,which is according to tungsten content reduced to form layer from outside to inside.with the heat-treatment temperature rose from 980^oC to1 050^oC,the phase of coating is WC.It is found by XPS,After diamond surface was modified by sputtering with time of 9h,that the W⁶⁺inos and W co-exist in the coatings,but also O ions are detected in the coatings.After 700??800?and 1050?heat-treatment for 2h,W simple substance increased and W⁶⁺ions decreased.at 1050?the coatings present as metal state,WC and a small quantity of W⁶⁺ions.Copper matrix composites reinforced diamond composites were successfully fabricated bypressureless infiltration method.The composition and structure of the composites are investigated using scanning electron microscopy?SEM?,x-ray CT.The results indicate that the composition of the coatings is WC.The microstructure and properties of Diamond/Cu composites were investigated.The results show that the Diamond/Cu composites were compact and WC transition layers onto diamond can greatly promote the compatibility between diamond and Cu.Further investigation reveals that the Diamond/Cu composites possess low density?5.39g/cm³?,excellent thermal management function as a result of high thermal conductivity up to 761W×m^-1×K^-1 and a fine tightness(2.5?10^-10 Pa×m³×s^-1).In order to improve the solder ability,a special sample was produced.The interface thermal resistance is calculated by related therory model.