As one of the most efficient ways to keep up with Moore’s Law, the electronics and semiconductor industry is increasingly developing new techniques for heterogeneous integration and advanced packaging. Nowadays, hundreds of different components can be combined into more and more complex packages.
A key enablement for realizing these assemblies are improvements of the package interconnects to increase performance, reduce the footprint, and lower power consumption. This includes smaller solder-based bump bonds (microbumps), smaller through silicon vias (TSVs), and solder-free hybrid Copper bonding. The ongoing miniaturization and stacking of components are driving the need for better metrology to speed up and improve inspection, quality assurance, and failure analysis. X-ray methods are promising since they have the potential to be non-destructive and probe large sample volumes. However, until recently, resolution of 2D and 3D X-ray has been a main limiting factor.
By utilizing state-of-the-art nano-focus X-ray sources, high-resolution inspection and failure analysis with voxel sixes below 100 nm and true JIMA resolution at 150 nm can be achieved. Here, measurements were acquired using a custom-built nano-CT and laminography system, equipped with the NanoTube N3 X-ray source. To illustrate the performance of the system, two different samples were measured: (i) a HBM memory stack from an Nvidia GV100 containing 8 layers of DRAM with 20um micro-bumps and (ii) an AMD Ryzen 7 5800X3D processor using hybrid bonding to connect the 3D V-Cache to the CPU cores. We demonstrate how to achieve sub-micron resolution in 3D using X-ray nano-CT and laminography.
From the resulting reconstructed slices, it is possible to detect and visualize voids and cracks in the 20um micro-bumps of the HBM memory. In the second example, the individual 1.5um hybrid copper bonds connectors with a pitch of 9um can also be clearly visualized.
Following ongoing developments with heterogeneous integration and advanced packaging, such as hybrid copper bonds and backside power delivery, high-resolution X-ray methods will become an increasingly important technique to support development, ramp up, and production of more complex electronic components and assemblies.
Speaker
Julius Hållstedt is the head of segment for semiconductor and electronics at Excillum, with the main focus on addressing the metrology challenge the industry is facing due to the increased complexity with smaller dimensions, increased dense packing and 3-dimensional structures causing many existing measurement techniques to run out of steam.
This talk was held during the IEEE Hybrid Bonding Symposium in 2025.
To view the webinar, please follow this link: Metrology for hybrid bonds, microbumps and TSVs in advanced packaging