Interconnection Mechanism And Reliability Study Of Low Temperature Pressure Copper Sintering

Power electronic devices are developing in the direction of miniaturization,high power and high integration,driving the need for updated semiconductor materials.Silicon based materials are difficult to meet the demand of high temperature applications,so the third-generation semiconductors,such as silicon carbide(Si C)and gallium nitride(Ga N),are emerging as rapidly developing alternatives.These materials possess high power density and switching frequency and other characteristics,leading to higher chip junction temperature that pose stringent challenges for packing materials.arious techniques for joining semiconductor materials exist,including high-temperature brazing materials,transient liquid-phase joining techniques,and sintered silver techniques all have their own drawbacks.Among the available options,metallic copper particles are considered ideal for wide-band semiconductor connections due to their low price,excellent thermoelectric properties,and better resistance to electromigration.Nonetheless,the easy oxidation of copper and the high sintering temperature limit the application of sintered copper technology.A method for producing sintered joints with high shear strength is described in this paper,which involves the use of metal organic decomposition(MOD)inks and ascorbic acid(AA)in a paste.The reaction of AA generates reduction prodects that not only participate in but promote the decomposition of MOD ink.As a result,the decomposition process consumes the reduction products,leading to a positive cycle.To determine the optimal ratio of MOD ink and AA,the paste component content was adjusted.The resulting sintered joints prepared at 250°C exhibited a remarkable shear strength of 102.22 MPa,which is significantly higher than the shear strength achieved when only MOD or AA was added to the paste(less than 5 MPa).This paper presents a systematic investigation into the effe cts of temperature,pressure and time on the shear strength,fracture morphology and densities of sintered joints.The study that the sintering temperature has the most significant impact on shear strength,followed by sintering pressure and sintering time.The method of extreme difference analysis and analysis of variance were used to determine the law of sintering factors affecting shear strength.The paste has excellent low-temperature sintering performance at 210°C with a shear strength of 43.02 MPa.High temperature aging and temperature cycling experiments were performed on the sintered joints.The results showed that the shear strength did not exhibit a decreasing trend after aging at 250°C for 1000 hours.Additionally,after 600 cycles at temperatures ranging from-40°C to125°C,the shear strength remained stable at 104.82 MPa.These findings indicates that the sintered joints prepared with this paste have excellent reliability.