Latest Advancements in nanoscale IR Spectroscopy for Failure Analysis of Electronic Devices
Latest Advancements in nanoscale IR Spectroscopy for Failure Analysis of Electronic Devices
Tuesday, November 7, 2017: 1:20 PM
Ballroom A (Pasadena Convention Center)
Summary:
Latest Advancements in nanoscale IR Spectroscopy for Failure Analysis of Electronic Devices Anirban Roy, Eoghan Dillon, Qichi Hu, Kevin Kjoller, Roshan Shetty and Craig Prater Anasys Instruments Inc., Santa Barbara, CA 93101, USA For the last few decades continuous development in the semiconductor process technology has led to systematic shrinking of the device features with sub-m resolution (cf. Moore’s Law).1 These advancements demand high resolution analytical tools for system characterization and failure analysis complementary to existing techniques. Nanoscale IR spectroscopy is an emerging technique that combines high spatial resolution of an AFM with reliable chemical analysis capability of IR spectro/microscopy (AFM-IR).2 Previously, nano-patterned metal/low-k dielectrics and nanoscale organic contaminations were successfully characterized exploiting the AFM-IR technique.3,4 We extended the capability of AFM-IR technology to facilitate higher sensitivity, spatial resolution and robust statistical analysis to broaden the range of applications in failure analysis of electronic devices. Figure 1. (a) Tapping mode height image of a Si wafer with organic residues. (b) AFM-IR spectra on (red) and off (blue) the contaminant. (c) Comparison of the measured AFM-IR spectra (Red) of the organic residue against library FTIR spectra of polyester (PET, Blue). (d) AFM and AFM-IR images of a test microelectronic structure; IR laser radiation was tuned to 2960 cm-1 to highlight the interlayer dielectrics (ILD). Process development for semiconductor devices involves a variety of chemical agents in hundreds of steps, therefore, contaminants are often multicomponent even within sub-μm residues and show mixed IR absorption features. In order to identify multiple components from a mixture, it is instrumental to push the spatial resolution limit of the AFM-IR technique. Recent innovations such as Tapping IR imaging augments the spatial resolution to 10 nm or better. In this modality the IR image at a specific absorption band is acquired simultaneously with standard tapping mode AFM images yielding high resolution chemical maps along with topography (height) and visco-elastic properties (phase). Tapping AFM-IR mode operation also offers superior applicability to wider range of samples ranging from particulates to thin films due to its non-invasive nature compared to contact mode AFM-IR imaging. Identifying a multicomponent residue in failure analysis often requires numerous measurements followed by rigorous statistical analysis. Our new Hyperspectral AFM-IR technology offers high speed spectral acquisition (50-100x times faster than previous generation) to acquire high quality spectral data over the whole imaging area. Subsequent statistical analysis yields spectra of individual components and generates chemical composition map to successfully identify contaminants and their spatial distribution. Figure 2. AFM topography (a) and chemical image at 1650 cm-1 (b) of a biological residue on Si wafer in Tapping AFM-IR imaging mode. Residue thickness is 5-6 nm.
Latest Advancements in nanoscale IR Spectroscopy for Failure Analysis of Electronic Devices Anirban Roy, Eoghan Dillon, Qichi Hu, Kevin Kjoller, Roshan Shetty and Craig Prater Anasys Instruments Inc., Santa Barbara, CA 93101, USA For the last few decades continuous development in the semiconductor process technology has led to systematic shrinking of the device features with sub-m resolution (cf. Moore’s Law).1 These advancements demand high resolution analytical tools for system characterization and failure analysis complementary to existing techniques. Nanoscale IR spectroscopy is an emerging technique that combines high spatial resolution of an AFM with reliable chemical analysis capability of IR spectro/microscopy (AFM-IR).2 Previously, nano-patterned metal/low-k dielectrics and nanoscale organic contaminations were successfully characterized exploiting the AFM-IR technique.3,4 We extended the capability of AFM-IR technology to facilitate higher sensitivity, spatial resolution and robust statistical analysis to broaden the range of applications in failure analysis of electronic devices. Figure 1. (a) Tapping mode height image of a Si wafer with organic residues. (b) AFM-IR spectra on (red) and off (blue) the contaminant. (c) Comparison of the measured AFM-IR spectra (Red) of the organic residue against library FTIR spectra of polyester (PET, Blue). (d) AFM and AFM-IR images of a test microelectronic structure; IR laser radiation was tuned to 2960 cm-1 to highlight the interlayer dielectrics (ILD). Process development for semiconductor devices involves a variety of chemical agents in hundreds of steps, therefore, contaminants are often multicomponent even within sub-μm residues and show mixed IR absorption features. In order to identify multiple components from a mixture, it is instrumental to push the spatial resolution limit of the AFM-IR technique. Recent innovations such as Tapping IR imaging augments the spatial resolution to 10 nm or better. In this modality the IR image at a specific absorption band is acquired simultaneously with standard tapping mode AFM images yielding high resolution chemical maps along with topography (height) and visco-elastic properties (phase). Tapping AFM-IR mode operation also offers superior applicability to wider range of samples ranging from particulates to thin films due to its non-invasive nature compared to contact mode AFM-IR imaging. Identifying a multicomponent residue in failure analysis often requires numerous measurements followed by rigorous statistical analysis. Our new Hyperspectral AFM-IR technology offers high speed spectral acquisition (50-100x times faster than previous generation) to acquire high quality spectral data over the whole imaging area. Subsequent statistical analysis yields spectra of individual components and generates chemical composition map to successfully identify contaminants and their spatial distribution. Figure 2. AFM topography (a) and chemical image at 1650 cm-1 (b) of a biological residue on Si wafer in Tapping AFM-IR imaging mode. Residue thickness is 5-6 nm.