Fluorescent microthermography
Encyclopedia
Fluorescent microthermography (FMT) is a microscopy
technique for infrared imaging of temperature distribution in small scale; the achievable spatial resolution is half micrometer and temperature resolution of 0.005 K
. Time-dependent measurements are possible, as the fluorescence lifetime is only about 200 microseconds.
A thin film of a phosphor
, europium thenoyl-trifluoroacetonate, is applied on the surface (e.g. an integrated circuit
die
) and illuminated by ultraviolet
light at 340-380 nm, stimulating fluorescence
at mainly 612 nm line. The quantum efficiency
of fluorescence decreases exponentially with temperature, differences in emitted light intensity can be therefore used to assess differences on surface temperature, with hot areas showing as darker.
Microscopy
Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...
technique for infrared imaging of temperature distribution in small scale; the achievable spatial resolution is half micrometer and temperature resolution of 0.005 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
. Time-dependent measurements are possible, as the fluorescence lifetime is only about 200 microseconds.
A thin film of a phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...
, europium thenoyl-trifluoroacetonate, is applied on the surface (e.g. an integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
die
Die (integrated circuit)
A die in the context of integrated circuits is a small block of semiconducting material, on which a given functional circuit is fabricated.Typically, integrated circuits are produced in large batches on a single wafer of electronic-grade silicon or other semiconductor through processes such as...
) and illuminated by ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light at 340-380 nm, stimulating fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
at mainly 612 nm line. The quantum efficiency
Quantum efficiency
Quantum efficiency is a quantity defined for a photosensitive device such as photographic film or a charge-coupled device as the percentage of photons hitting the photoreactive surface that will produce an electron–hole pair. It is an accurate measurement of the device's electrical sensitivity to...
of fluorescence decreases exponentially with temperature, differences in emitted light intensity can be therefore used to assess differences on surface temperature, with hot areas showing as darker.