Preparation And Microstructure Evolution Mechanism Of Bondlines Fabricated By Infiltrating Porous Cu With In

In response to the trend toward the increasingly miniaturization of electronic devices,the integration of devices has also increased.Due to the large increase in current density and power density,the chip generates a large amount of heat during operation,and the chip needs to have sufficient high temperature resistance.Third-generation semiconductor materials such as SiC have excellent performance,especially high temperature resistance,which can meet the development requires of electronic devices.However,the key issue is the lack of high-temperature chip mount materials.In order to solve these problems,this paper proposes two kinds of bondlines structures,a novel TLP bondlines,a Cu-Cu interconnected bondlines,which aim to achieve ‘low temperature connect quickly and high temperature service'.The precursor Cu-Zn alloy was prepared by electroplating,and it was found that the alloy structures prepared by different main salt ion concentration plating solutions were different.Then the porous Cu structures obtained after the subsequent de-alloying treatment were different.According to the characteristics of the two structures of porous Cu,they were applied to the preparation of bondlines of different structures.The properties of the bondlines of the two structures and the mechanical properties after aging were tested.For the novel TLP bondlines,the low melting point solder In was completely consumed in the conditions of 165 °C for 10 min under the pressure of 0.75 MPa.The bondlines were composed of densified porous Cu and ? phase,Cu₁₁In₉ phase.At weld temperature of 310 °C,the bondlines that had a melting point of more than 600 °C were composed of a densified porous Cu and ? phase and ? phase.Through the observation of the microstructure of the bondlines,it was found that the number and size of the holes at the edge of the joints increased with the extension of the welding time and the temperature.Analysis showed that this phenomenon was caused by volume change during phase change and Kirkendall effect.The resistivity prepared at 165 °C for 10 min was 5.53 ??·cm,and the thermal conductivity was 131.49 W·m^-1·K^-1.The room temperature shear strength was 19.09 MPa.After aging,the shear strength reduced because of the increase of pores.For the Cu-Cu interconnected bondlines,effective connections can be achieved under low temperature and low pressure conditions of 150 °C and 3 MPa for 10 min.The bonding lines were sintered to realize the connection,and the porous Cu on both sides were thermally roughened.After the bondlines etched by the Cu etching solution,it was found that the degree of densification at the bonding lines was better than that of both sides.As the bonding temperature and the pressure was increased,the density of the bondlines were significantly improved.The resistivity prepared under this condition was 4.12 ??·cm,and the thermal conductivity is 176.49 W·m^-1·K^-1.The room temperature shear strength was 18.78 MPa.After aging,the shear strength was increased due to the increase of the degree of bondlines densification.