The automated metrology capabilities of a STEM using a commercially available 22nm microprocessor were evaluated. Artifact-free TEM samples with a thickness of 10-15nm were prepared from inverter structures at various locations within an SRAM array. Static and dynamic precision measurements made on fin and gate stack features show sub-nm precision, suggesting that fully automated STEM metrology on finFET devices is capable of supporting finFET production. This paper also discusses sample preparation, automated data acquisition and data analysis, as well as the throughput benefits that arise from hardware connectivity between the sample prep and data acquisition tools. Simultaneous STEM imaging and compositional analysis is also briefly discussed.
We report recent advances in tool and process hardening of a first of its kind 300 mm wafer-to-wafer (WtW) preprocessing, aligning, and bonding integrated tool. We have demonstrated sub-500 nm post-bond alignment accuracies for 300 mm WtW face-to-face (FtF) Cu-Cu thermocompression bonds, WtW FtF Si-Si fusion bonds, and WtW FtF oxideoxide fusion bonds. All process of record (POR) recipes that were developed had undetectable voids based on scanning acoustic microscope (C-SAM) measurements on representative bonded Cu, oxide, and Si blanket wafers. Optimized bonded patterned wafer splits in the Cu-Cu WtW thermocompression bonding step have shown alignment accuracies down to ∼190 nm, the highest accuracy to date. Using an infrared-enabled, high speed focused ion beam (FIB) system (with XeF 2 ) with a CAD overlay function to assist in selective sample preparation, we have verified that the bonding interfaces at the via chain structures with 1–5 μm diameter vias show no interfacial voids. Also, there is evidence of Cu interdiffusion, as supported by transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD) data.
Recent developments in aberration-corrected transmission electron microscopy have drawn much attention from the semiconductor characterization community. Two new developments in transmission electron microscopy, image aberration correctors and probe aberration correctors, are discussed in term of their applications in characterizing gate oxide dielectrics for the IC industry.
