焊球植球凸块工艺的可靠性研究

Reliability Research of Solder Ball Placement Bumping Process

焊球植球是一种最具潜力的低成本倒装芯片凸块制作工艺。采用焊球植球工艺制作的晶圆级芯片尺寸封装芯片的凸块与芯片表面连接的可靠性问题是此类封装技术研究的重点。为此,参考JEDEC关于电子封装相关标准,建立了检验由焊球植球工艺生产的晶圆级芯片尺寸封装芯片凸块与芯片连接及凸块本身是否可靠的可靠性测试方法与判断标准。由焊球植球工艺生产的晶圆级芯片尺寸封装芯片,分别采用高温存储、热循环和多次回流进行试验,然后利用扫描电子显微镜检查芯片上凸块剖面的凸块下金属层分布和测试凸块推力大小来验证凸块的可靠性。试验数据表明焊球植球工艺生产的晶圆级芯片尺寸封装芯片具有高的封装连接可靠性。

The solder balls placement technology is the most potential low cost flip chip bumping method for bumps manufacture.The connection reliability of the bumps to the chip is the most important research aspect of the package technology.According to the reference of the relevant JEDEC standards for electronic assembly,the reliability test method and judgment criteria for the bumps were built up,which can detect the bumps and the connection between the chip and the bumps made by solder balls placement technology for the wafer level chip scale package.For the wafers made by solder balls placement technology,the high temperature storage,thermal circling and multi reflow test were used.The metallurgy distribution of the bump underlayer at the bump cross-section on the chip was checked by SEM and the bump process reliability was verified by measuring the shear force to the bumps.The test results show that the wafer level chip scale package chips made by solder balls placement technology have a high connection reliability.