Abstract The latest IC modification requirement is to decrease the resistivity of Focused Ion Beam (FIB) deposits, especially deposits within a FIB machined hole. The resistivity of platinum conductor deposited by FIB within a hole is much greater (5000-50000 μΩ-cm) than that deposited on a surface (~200 μΩ-cm) (1). Auger analysis of surface deposited platinum conductor gives the composition ratios as ~ 50% platinum, ~34% carbon, ~15% gallium and ~1 % Oxygen. The escape solid angle of the organic carrier is much less from a hole than from a surface; therefore, we find more of the non-conductive organic material is trapped inside the hole which increases the fill resistivity. With its planarization and multiple metal levels, advanced IC process technology forces contact to lower level metal to be through high aspect ratio holes. To make a low resistance contact through such a hole, deposited material must have a high ratio of platinum to carbon and Oxygen. An improved technique is needed to remove the organic carrier molecules and deposit material containing this higher platinum percentage. The way to achieve such deposition is to adjust gas arrival rate and beam current to produce a deposition rate that allows sufficient time for the organic carrier molecules to escape. Using this method, we can to obtain fill resistivity of about 1000-2500 μΩ-cm within high aspect ratio holes. This paper discusses in detail the technique to achieve such low resistivity in high aspect ratio holes. On the surface where space is not so limited, a greater deposition rate yields shorter times to resistance as well as better step coverage, but within a hole a lower resistivity material is needed to result in good conductance to lower level metal.

Abstract It is becoming more important to observe structures and failed sites in LSIs. An atomic force microscope (AFM) can obtain atomic scale topographic images on sample surfaces. To analyze failures in LSIs, several treatments for the AFM observation, such as wet etching and mechanical polishing for a crosssectional imaging, have been proposed so far. A good correlation of AFM images using FIB anisotropic etch with those acquired by conventional technique such as SIM and TEM has been demonstrated A crystallographic information about Al thin film is obtained by AFM using this technique.

Abstract This paper describes how faulty thin-film transistors (TFTs) having fragile structures in themselves can be characterized by cross-sectional transmission electron microscopy (X-TEM) through the achievement of pinpoint accuracy in focused ion beam (FIB) etching. We demonstrate X-TEM analysis for faulty TFTs caused by mechanical damages, microvoid in their multilayers and long aluminum whiskers growing from the electrodes. X-TEM specimen were prepared by FIB etching without losing unique structures owing to fragile locations. Cross-sectional bright-field TEM micrographs clearly showed the details of cross sectional structure of fragile location. This pin-point X-TEM is quite helpful to identify faults and to reveal root causes of failures.

Abstract EBIC (Electron beam induced current) method has been applied to the evaluation of half micron MOSFET junctions. We have been able to clearly measure the junction depth profile and the impurities density, using FESEM/EBIC which provides the highest SEM resolution currently available. We have found that it is necessary to understand the relation of the acceleration voltage and the primary electron beam current, in order to take full advantage of the FESEM/EBIC technique for junction evaluation. We have been able to experimentally demonstrate the accurate measurement of junction position.