Improved Resolution in Advanced Packaging Metrology Through Advanced Nano-Focus X-Ray Sources

In the pursuit of ‘More Moore’ and ‘More than Moore’, the interest in X-ray source technology has intensified since many of the traditional methods to measure and control semiconductor manufacturing such as optical or electron-based metrology methods are running out of steam. Heterogeneous integration and advanced packaging offer the possibility to optimize and increase the performance of devices while keeping costs down. As the dimensions of the electrical connects are continuously reduced in size and pitch this enables more connections and faster communication. At the same time, this puts increased demand on the resolution of the metrology tool as critical defect dimensions of the electrical interconnects such as micro-bumps and through silicon vias (TSV) are getting smaller down to sub-micrometer level. The proposed solutions involve acoustic, optical, electrical and X-ray imaging techniques. However, X-rays have a clear advantage as it can probe large 3D volumes and measure the internal structure of devices non-destructively. For advanced packaging and heterogenous integration, the resolution of the X-ray reconstruction topographies has previously been a key limitation. In this communication it is shown that detailed submicron analysis of HBM micro-bumps and TSVs is possible with X-ray tools.