Preparation And Properties Study Of Antioxidant Copper Electronic Pastes

Because of the rapid development of the electronics industry,electronic pastes play a more and more important role in the key electronics materials.High performance and low cost products not only have greater competitive advantage,but also become the development trend of electronic pastes.Using the precious metals as the conductive filler,the electronic pastes show good performance.But in recent years,because of the rising prices of precious metals,the cost of electronic pastes are higher and higher,so the application of electronic pastes has been limited.The copper receives extensive attention of people due to the excellent electrical conductivity and low prices.But the copper paste presents the poor stability because of the oxidation of copper,the key technology of copper electronic pastes is anti-oxidation.In this paper,the effects of conductive filler particle size and shape,conductive filler content,reductant and dispersant content,coupling agent addition,the configuration of the organic carrier,curing temperature and curing time on the low temperature curing copper electronic pastes in the air as the research object have been studied systematicly.The phase of copper powders has been characterized by X-ray diffraction?XRD?,the morphology of copper powders and copper films are characterized by scanning electron microscope?SEM?,four point probe resistance tester measures the resistivity,the high temperature display viscometer measures the paste viscosity,and the thermogravimetric analyzer measures the thermal stability.Meanwhile,the oxidation resistance and reliability have been explored.The study shows:?1?The better performance of pastes has been reached using copper powder by ball milled as conductive filler and direct addition of the coupling agent.The best resistivity of curing copper film,3.946×10^-3?·cm,aftering curing has been reached using the ascorbic acid?Vc?as reducing agent,polyvinylpyrrolidone?PVP-K30?as dispersing agent,and W_?Cu?:W_?Vc?:W_?PVP?=63⁷1:20²5:9¹1,respectively.?2?The pastes show the better performance using polyamide resin as the curing agent and the content is 30%³5%of epoxy resin.The content of the organic carrier content is 30%,the copper film is insulated because the content of copper powder is below the percolation threshold.When the organic carrier content is 10%²5%,the resistivity decreases firstly and then increases.When the mass ratio of organic carrier and Cu_+Vc+PVP is15%:85%the smallest resistivity is 3.627×10^-3?·cm.The better printing,viscosity,and adhesion strength have been showed this moment.?3?Copper electronic pastes show the good thermal stability under 225?.The resistivity of copper film changes slowly and has good oxidation resistance at room temperature.But under the environment of 70?,the resistivity increases faster and the oxidation resistance becomes worse.The change of the resistivity of copper film under the natural environment and cured at 70?is 54.8%;the change of the resistivity of copper film cured at 55?is 67.5%in the first 80 days,that shows the better reliability of the copper film than the former.Under the thermal aging environment,copper film resistivity grows rapidly and shows poor reliability.