Advanced X-ray Imaging Technologies for Heterogeneous 3D IC Package Metrology and Inspection

#WLP #3D #inline #inspection #buried #layers #high #resolution #tomography #multi-chiplet #submicron #defects #heterogeneous #integration

The advent of 3D Heterogeneous Integration (3DHI) in advanced packaging and wafer-level IC packaging introduces significant challenges for inline defect inspection and offline failure analysis. The 3D stacking and wafer bonding processes create optically opaque structures, necessitating techniques like x-rays to penetrate multiple buried layers for defect detection. However, as device features in 3DHI continue to shrink (e.g., microbumps shrinking to <10 µm in diameter and TSV interconnects scaling to single-digit micrometers), existing non-destructive techniques face substantial technological barriers. Current 3D X-ray methods require higher resolutions to meet these evolving demands, and acquiring sub-micron imaging data using conventional x-ray tomography can take hours or be impractical for large 300 mm wafers. To bridge these metrology gaps, we have developed two innovative 3D x-ray inspection tools:
1. High Throughput (3D Data in Minutes): This tool is designed for the rapid inspection of 300 mm wafers during wafer-level packaging and bonding. It can automatically resolve various 3D defects down to 0.5 µm resolution within minutes. It is also capable of addressing high-resolution multi-chiplet inspections, large advanced packages or board-level failure analysis, such as for PCBs.
2. High Resolution (300 nm spatial Resolution): This complementary tool aims to surpass the resolution limits of current leading high-resolution 3D x-ray and x-ray microscopes (XRM) for the failure analysis of advanced heterogeneous packages. It delivers true 300 nm spatial resolution (<50 nm voxel) for characterizing submicron defects in microbumps, delamination, voids, interfacial cracks, and RDL that are beyond the capabilities of existing XRMs.