Method for preparing high-resolution emitter tungsten tip and device thereof

Abstract

The invention discloses a method for preparing a high-resolution emitter tungsten tip and a device thereof, and relates to a liquid metal ion source with high-resolution secondary ion mass spectrometry (SIMS). The invention provides the method for rapidly and safely preparing the emitter tungsten tip with simpleness and high repeatability. The device is provided with an AC voltage signal generating circuit, a corrosion current monitoring circuit, a corrosion voltage monitoring circuit, an automatic corrosion control system, a spiral micro-regulator, a corrosion electrolytic cell and a constant temperature control system. Corrosion solution is placed in a cooler for low-temperature cooling before the manufacture and taken out till a certain temperature, then the cooler with the corrosion solution is horizontally fixed in the constant temperature controller, and the constant temperature control system is regulated for keeping the temperature of the corrosion solution at constant temperature. A clean tungsten wire is taken and annealed by hydrogen flame, one end of the tungsten wire is fixed on the spiral micro-device and used as a pole, and the other pole is a metal annular electrode placed in the NaOH corrosion solution; the metal annular electrode is horizontally placed at the middle and lower part at the bottom of the corrosion electrolytic cell; a central point of the metal annular electrode is taken by the tungsten wire and vertically inserted in the corrosion solution; the tungsten wire is inserted in the corrosion solution, and the insertion depth is kept; the corrosion current is monitored till the corrosion current achieves a threshold; pulse corrosion is continued, and roughening treatment is carried out on the tip, and the length to width ratio of the tip is controlled.

Description

technical field [0001] The invention relates to a liquid metal ion source for high-resolution secondary ion mass spectrometry (SIMS), in particular to a method and a device for conveniently and effectively preparing a high-resolution emitter W needle tip. Background technique [0002] The high-resolution secondary ion mass spectrometry (SIMS) liquid metal ion source has many applications in the fields of focused ion beam micromachining, microscopy, and mass spectrometry. The size, shape and liquid metal composition of the probe directly affect the resolution quality of the secondary ion mass spectrometer. The sharper the tip and the more symmetrical the shape, the higher the resolution and image quality. At present, there are mainly methods for preparing W needle tips, such as mechanical forming method and electrochemical corrosion method. The equipment is simple and easy to operate, and high-quality needle tips can be obtained. Electrochemical corrosion methods for W-tips...

AI Technical Summary

Problems solved by technology

It is difficult to prepare an emitter tip with ultra-high resolution and stable emission of liquid metal by conventional methods. If the aspect ratio of the tip is too large, the flow rate of liquid metal will be insufficient and in practical applications, there will be a gap between the emitter tip and the extraction electrode. Ignite and damage the emitter tip; if the aspect ratio of the needle tip is too small, it will increase the threshold voltage of the emitter, which will cause the withstand voltage problem between the electrodes

Conventional methods are not suitable for preparing high-resolution liquid metal ion source tips

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