|
Self-assembled molecules (SAM) are used as an inhibitor in conjunction with atomic layer deposition (ALD) for selective area deposition. Given the extremely thin film and the pattern density involved in this type of process, currently available analytical tools have difficulty in analyzing the quality and selectivity of each processing step. For example, while FTIR may provide evidence of SAM coverage, it cannot assure the quality of coverage, especially on a scale relevant to current processing requirements. Similarly, electron microscopes that can provide excellent spatial resolution and elemental analysis cannot determine the quality of the ultrathin thin organic and selective inorganic deposition layers. In this paper, a relatively new technique called photo-induced force microscopy (PiFM), which combines atomic force microscopy (AFM) and infrared (IR) spectroscopy with sub-10nm spatial resolution, is used to analyze the deposition of SAM layer and subsequent alumina deposition on metal/SiO2 test patterns (80nm being the smallest pitch). PiFM spectra can unambiguously identify the different chemical species (SAM, SiO2, and alumina) via their IR signatures. PiFM images at fixed wavenumbers associated with the different chemical species provide chemical mapping in real space with sub-10nm spatial resolution, clearly illuminating how selective different processing steps are. The paper will show how the nanoscale hyperspectral PiFM data can provide unambiguous and speedy feedback to process engineers engaged in selective deposition.
|
