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Metrology of the properties of materials is a growing concern in semiconductor manufacturing and as a result, new and existing technologies are being adapted to address gaps in established capabilities. We introduce here Scanning Microwave Impedance Microscopy (sMIM), a technology that can measure critical material properties such as dielectric constant (k-value), capacitance, resistivity and permittivity at the nanoscale. In this technique, an AFM cantilever is used as a microwave source to measure the electrical properties of materials at nanometer scale. sMIM is sensitive to the local capacitive and conductivity changes in a material making it an excellent method to apply on a wide range of materials such as insulators, semiconductors, ferroelectrics and other. An sMIM measurement provides the permittivity and conductivity of films. From this measurement you can derive properties such as dopant concentration, resistivity and identify certain defects. Since microwaves can penetrate deep into the sample, we can measure sub-surface layers as well. The resolution of the sMIM ScanWave system for capacitance measurements has been calculated to be better than 0.3 aF and the repeatability is well below 1% RSD 1σ making suitable for very sensitive process control of dielectric films and dopant concentration. Types of measurements presented here include nano C-V for dielectric film quality, dielectric film k value and dopant concentration. Additional applications are envisioned in emerging memory materials.
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