METHOD FOR TOMOGRAPHIC SAMPLE ANALYSIS IN SCANNING ELECTRON MICROSCOPE Russian patent published in 2012 - IPC H01J37/28 

FIELD: physics.

SUBSTANCE: invention relates to scanning electron microscopy and can be used for nondestructive layer-by-layer testing of samples, particularly micro- and nanoelectronic articles. The invention employs the ability of back scattered electrons to cause deposition of molecules of residual hydrocarbons adsorbed on the surface of a sample. When the sample is exposed to a focused electron beam, a carboatomic ring forms around the incidence point of the beam. The diameter of the ring depends on the composition, thickness and depth of layers crossed by the back scattered electrons. That dependency is the basis of tomographic analysis. The ring is an analogue of a spectral mark - a unique characteristic of the sample. The position of the mark on the surface of samples with a variable layer-by-layer structure is traced on a model. Layers at different depth are involved in the analysis when the accelerating voltage is changed. The electron track length in the sample is determined from measurements of carboatomic rings formed on the surface at different angles of inclination to the axis of the beam. The possibility of distinguishing solid substrates, including silicon and gallium arsenide, under a double-layer coating with depth resolution of not less than 10…100 nm is exhibited. Depending on the accelerating voltage, horizontal resolution varies from several micrometres to several hundreds of nanometres.

EFFECT: high reliability and accuracy of processing measurement results.

5 cl, 12 dwg