Due to the process issues,3D package structures with sidewall interconnect inevitably produce a copper oxide layer on the surface of the sidewall redistribution stubs,which results in higher contact resistance at the interconnect interface. The samples processed under different pre-treatment conditions were analyzed using the breakdown method. The interconnect interface of the samples after breakdown was characterized by X-ray spectroscopy,selected area electron diffraction,and high-resolution transmission microscopy. The results show that the breakdown method can achieve a resistance reduction effect of over 95％ for the samples prepared under different baking environments,baking time,and cleaning processes. Additionally,the contact resistance is reduced to below 1 Ω in all cases. The contact resistance of the sample,prepared by vacuum baking,baking for 10 hours,and plasma treatment,reaches a minimum of 0.26 Ω after the breakdown treatment. With the breakdown method,the contact resistance of the interconnect interface is reduced by applying an electric field to the copper oxide layer. As a result,the copper ions migrates along the direction of the electric field and is reduced to polycrystalline Cu and Cu2O,forming a low-resistance conductive path. It is shown that the breakdown method is suitable for reducing the contact resistance of the interconnect interface in the sidewall interconnect process.
关键词
3D封装/侧壁布线/互连界面/铜氧化膜/接触电阻/击穿
Key words
3D package/sidewall interconnect/interconnect interface/copper oxide film/contact resistance/breakdown
维普
万方数据