ANGLE LAPPING OF MULTILAYER STRUCTURES FOR THICKNESS MEASUREMENTS USING FOCUSED ION-BEAM MICROMACHINING

Focused ion beam (FIB) micromachining has been carried out to angle-la p multilayer structures for layer thickness measurements. A Ga+ FIB or iginating from a liquid metal ion source (LMIS), operated at 10 kV, wa s employed throughout. The FIB was digitally rastered, pixel by pixel, in a serpentine fashion over the area of interest, and the pixel dwel l time was incremented line by line. The multilayers used were Al/SiO2 /Si and Al/TiW/SiO2/Si. For the conditions set up for the FIB scan rou tine, control in micromachining the angle of the lapped surface is of the order of 1arcsec per scan of the ion beam over the area of interes t. Use of absorbed current for the purpose of end-point detection and monitoring of the angle lapping fabrication progress is demonstrated.