Investigations On The Preparation And Characterization Of Inner Electrode Conductive Copper Paste For LTCC Applications

With the progress of the time,and the vigorous development of the microelectronics industry,in recent years,with the rapid development of microelectronic products,military,communication and other consumer electronic products gradually advance towards miniturazation,light,portable and high reliability.The traditional electronic pastes using precious metals are gradually unable to meet the requirements of modern electronic products.Therefore,the novel electronic paste using base metals stands out and gradually replaces the traditional electronic pastes,becoming the compatible products of electronic devices in the new era.In this thesis,the inner electrode copper conductive paste used for LTCC applications was chosen as the objective.It was investigated the impact of chemical treatment on the dispersing and reducing properties of copper powder,and the influence of organic solvent on the viscosity of paste.And also the experiments were pursued to reveal the differences in the product performance caused by the different glass powders,which indicated how to select the glass powder.Moreover,some experiments were carried out to illustrate how the sintering process can impact the properties of the paste.With all the parameters set well,the inner electrode copper conductive paste was fabricated,which is suitable for LTCC applications.The grain size,thickness and surface morphology of copper film were observed and analyzed using the cold field emission scanning electron microscope.The square resistance was measured by a four probe tester,the slurry viscosity was examined by an Antonpa mcr302 equipment,and the adhesion force was evaluated by the tension meter.The main results are summarized as follows,(1)The copper powder was pretreated with oleic acid to prevent it from being oxidized when it was dried at 80?,and the copper paste prepared had a good electrical conductivity.(2)Li₂O-B₂O₃-Zn O system glass powder was prepared,the mass ratio was 20:40:40,the prepared slurry was sintered at 950?,and the melting temperature of obtained glass was 830?.The electrode copper film was dense,and the square resistance was 5.7 m?/?.(3)Different dispersants were used to prepare the organic vehicle which can adjust the viscosity of the slurry.Finally,polyvinylpyrrolidone was used as the dispersant to prepare the slurry with the viscosity of 200 Pa·s.The rheological property and screen printing performance of the slurry were good.(4)The sintering performance of copper paste in atmosphere was studied,and a copper electrode with good conductivity was obtained.The minimum square resistance can reach2.9 m?/?.Finally,the copper paste with adjustable performance and suitable for low oxygen partial pressure atmosphere was obtained.