High resolution scanning probe microscopy techniques combined with infrared (IR) light sources offer unique solutions to combined chemical/mechanical/electrical characterization of defects in nanoscale dimensions. Previously, atomic force microscopy combined with infrared (AFM-IR) technology has demonstrated its capability to characterize nano-patterned metal/low-k dielectrics, nanoscale organic contaminants, and directed self-assembly of block co-polymers used for advanced micro/nanofabrications. In this paper, two complementary nanoscale chemical analysis techniques, photothermal AFM-IR and scattering type scanning near-field optical microscopy, are implemented to isolate and characterize microelectronic device cross-sections. It is observed that both techniques are able to detect patterned features with a half-pitch less than 15 nm.

Atomic force microscopy infrared (AFM-IR) technology combines the best of both worlds of AFM and IR spectro-microscopy offering high spatial resolution chemical characterization. Recent developments in the AFM-IR technique, such as tapping AFM-IR pushes the spatial resolution limit below 10 nm, making it ideal for chemically characterizing directed self assembly (DSA) components and defects for failure analysis. This paper demonstrates the chemical characterization of DSA nanopatterns using tapping AFM-IR technology with spatial resolution beyond 10 nm. Tapping AFM-IR experiments is performed on different block copolymers routinely used to fabricate directed self-assemblies on Si wafers. Along with chemical mapping, mechanical properties, such as relative stiffness and damping yielding complete chemical and mechanical property information in nanoscale to achieve material contrast, can be simultaneously probed.

Continuous development in the semiconductor process technology has led to the fabrication of devices with nanometer scale feature resolution. Resonance enhanced atomic force microscopy infrared (AFM-IR) is a novel technique with potential to overcome some limitations of existing tools. This manuscript illustrates chemical characterization of the nanoscale skin and polyester contaminant on silicon wafer using resonance enhanced AFM-IR spectroscopy. Resonance enhanced AFM-IR offers superior sensitivity for nanoscale organic contaminants. To demonstrate this capability, AFM-IR spectra were obtained from contaminants on silicon wafers, and the spectra correlated with a high confidence to a standard transmission FTIR spectral database. In addition, a newly developed high speed spectral acquisition scheme, which augments the reliability of nanoscale defect characterization by reducing the overall data acquisition time and enabling users to perform repeated measurements for statistical analysis, is established.

Low yield was reported for a non-volatile embedded memory array. In one case, the n-channel transistor was observed to exhibit single bit OFF leakage in a 32K array. In another case, there was general leakage observed between drain junctions of neighboring transistors, even though these were isolated by field oxide. The objective of the failure analysis described in this article was to characterize the electrical behavior of the leakage and determine the exact location and cause of the leakage. Focused Ion Beam was used to make electrical contact to drain regions, which lacked a contact for microprobing. Once the electrical parameters were obtained, photoemission analysis was performed with modified probes for higher spatial resolution to pinpoint the leakage path. Finally, scanning capacitance microscopy methods were used to prove the presence of the n-type depletion path. Very clear and positive confirmation of the presence of the parasitic n-type dopant was confirmed.