3D integration |
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Bringing 3D to production requires thorough process control in order to insure technically and economically competitive manufacturing.
3D integration of electronic systems can be addressed in many different ways and a large variety of through-Si via (TSV) technologies is being proposed. These approaches can be categorized by the place of the 3D interconnects in the interconnect hierarchy. The TSV approaches roughly fall into two categories: TSVs addressing interconnects at the bond pad level (Via last) and interconnects at the level of on-chip electrical wiring (Via first or middle). The 3D integration process is pushing demand for ultra-thin semiconductor wafers. As wafer thickness decreases to 100µm and below, manufacturing challenges arise especially for 200 and 300 mm wafers. Ultra-thin wafers are less stable and more vulnerable to stresses, and die can be prone to breaking and warping - not only during grinding but also at subsequent processing steps. To address these challenges, temporary wafer carriers were developed to support the wafer during backgrinding and subsequent post-thinning processes. The thinning process requires thickness and TTV measurement of the stack substrate and of the silicon individual layer at the same time. |