An improved method for high resolution thermal mapping is discussed. This method utilizes nematic liquid crystals and has been primarily applied to inspect microcircuits. By making use of two nematic liquid crystals in conjunction with reflected light polarizing microscopy a thermal resolution of about 0.05 K has been achieved. Resolution limits are considered in detail for heat generation occurring at some depth from the surface of the sample. In addition, a comparison is made between the commonly used cholesteric method and the present work. To demonstrate the capability of the method the thermal mapping of an LED is shown.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry