A multiple-tip ultra-high vacuum (UHV) scanning tunneling microscope (MT-STM) with a scanning electron microscope (SEM) for imaging and molecular-beam epitaxy growth capabilities has been developed. This instrument (nanoworkbench) is used to perform four-point probe conductivity measurements at µm spatial dimension.The system is composed of four chambers, the multiple-tip STM/SEM chamber, a surface analysis and preparation chamber, a molecular-beam epitaxy chamber and a load-lock chamber for fast transfer of samples and probes. The four chambers are interconnected by a unique transfer system based on a sample box with integrated heating and temperaturemeasuring capabilities. We demonstrate the operation and the performance of the nanoworkbench with STM imaging on graphite and with four-point-probe conductivity measurements on a silicon-on-insulator (SOI) crystal. The creation of a local FET, whose dimension and localization are respectively determined by the spacing between the probes and their position on the SOI surface, is demonstrated.3

An electrochemical procedure in KOH electrolyte has been developed to reproducibly produce ∼5 nm radius tungsten probe tips. It has been found that a spurious electrochemical etching process, driven by the natural potential difference between an Ir electrode and the W tip, causes rapid tip blunting at the end of the electrochemical etching period. By electrically reversing this potential difference within 500 ns following tip separation, the blunting process is eliminated yielding sharp tips with varying cone angles.

A dismantling process for separating electric and electronic components (EECs) from printed circuit board (PCB) was developed by using hydrochloric acid (HCl) leaching with stannic ions (Sn 4+ ). The use of HCl solution with Sn 4+ ions dissolves tin (Sn)-alloy solder that holds EECs on bare board, which allows the EECs to be detached from PCB. The feasibility of the new dismantling process was investigated by examining the effects of temperature, initial Sn 4+ concentration and agitation speed on the dismantling of PCB. The effect of agitation speed was negligible and the dismantling-completion time was reduced rapidly with increasing temperature and initial Sn 4+ concentration. The dismantling of PCB was completed within 30 min under the leaching conditions; HCl concentration, 1 mol/L; initial Sn 4+ concentration, 13,000 mg/L; temperature, 90 C; and agitation speed, 300 rpm. Each metal was enriched after dismantling process; e.g. the content of Ag increased from 0.016% in PCB to 3.118% in registor. It was expected that ef cient PCB recycling process could be designed to recover metals from EECs with higher concentrated metals.

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