A charged particle microscope and a method of operating a charged particle microscope are disclosed. The microscope employs a source for producing charged particles, and a source lens below the source to form a charged particle beam which is directed onto a specimen by a condenser system. A detector collects radiation emanating from the specimen in response to irradiation of the specimen by the beam. The source lens is a compound lens, focusing the beam within a vacuum enclosure using both a magnetic lens having permanent magnets outside the enclosure to produce a magnetic field at the beam, and a variable electrostatic lens within the enclosure.

A magnetic gun lens and an electrostatic gun lens can be used in an electron beam apparatus and can help provide high resolutions for all usable electron beam currents in scanning electron microscope, review, and/or inspection uses. An extracted beam can be directed at a wafer through a beam limiting aperture using the magnetic gun lens. The electron beam also can pass through an electrostatic gun lens after the electron beam passes through the beam limiting aperture.

A conventional method to process a tip fails to designate the dimension of the shape of the end of the tip, and so fails to obtain a tip having any desired diameter. Impurities may be attached to the tip. Based on a correlation between the voltage applied or the time during processing of the end of the tip and the diameter of the tip end, the applied voltage is controlled so as to obtain a desired diameter of the tip end for processing of the tip. This allows a sharpened tip made of a tungsten monocrystal thin wire to be manufactured to have any desired diameter in the range of 0.1 ?m or more and 2.0 ?m or less.

The present invention relates to an electron gun for facilitating position adjustment, and an electron microscope including the same, the electron gun improving a vacuum structure so as to easily move a filament block or an electron tip of an electron gun without having bellows for maintaining a vacuum when the center axis of the filament block or the electron tip of the electron gun is mechanically misaligned with the center axis of a anode and a focusing lens.

The emitter of the present invention includes a nanowire. The nanowire is formed from a hafnium carbide (HfC) single crystal, and at least an end portion of the hafnium carbide single crystal, from which electrons are to be emitted, is covered with hafnium oxide (HfO.sub.2). In the emitter, the thickness of the hafnium oxide may be 1 nm to 20 nm.

An emitter with a protective cap layer on an exterior surface of the emitter is disclosed. The emitter can have a diameter of 100 nm or less. The protective cap layer includes ruthenium. Ruthenium is resistant to oxidation and carbon growth. The protective cap layer also can have relatively low sputter yields to withstand erosion by ions. The emitter may be part of a system with an electron beam source. An electric field can be applied to the emitter and an electron beam can be generated from the emitter. The protective cap layer may be applied to the emitter by sputter deposition, atomic layer deposition (ALD), or ion sputtering.

There is provided an electron microscope capable of producing good images by reducing contrast nonuniformity. The electron microscope (1) includes: an electron beam source (11) for producing an electron beam; a noise cancelling aperture (12) and an amplifier (42) for detecting a part of the electron beam; an effective value computing circuit (44) and a low frequency cut-off circuit (46) for extracting a DC component of an effective value of a detection signal emanating from the amplifier (42); an image detector (15) for detecting a signal produced in response to impingement of the beam on a sample (A); a preamplifier circuit (20) and an amplifier circuit (30); a divider circuit (54) for performing a division of the output signal (X) from the amplifier circuit (30) by the output signal (Y) from the amplifier circuit (42) and producing a quotient signal indicative of the result of the decision (X/Y); and a multiplier circuit (58) for multiplying the quotient signal by a signal (Z) extracted by the low frequency cut-off circuit (46).

Provided is a charged particle beam device that can precisely manage a temperature at which a cold field emitter is heated. A charged particle beam device includes: a cold field emitter including a tip having a sharpened distal end, a filament connected to the tip, and an auxiliary electrode covering the filament and having an opening from which the tip protrudes; an extraction electrode to which an extraction voltage for extracting electrons from the cold field emitter is applied; and an acceleration electrode to which an acceleration voltage for accelerating the electrons extracted from the cold field emitter is applied. When the tip and the filament are heated, thermionic electrons emitted from the tip and the filament are collected by the auxiliary electrode to measure a current by applying a positive voltage with respect to the tip to the auxiliary electrode.

Extractors and extractor systems minimize the generation of secondary electrons which interact with and degrade the primary electron beam. This can improve the performance of an electron beam system, such as a scanning electron microscope. The extractor may include a frustoconical aperture that widens as distance from the source of the electron beam increases. The entrance into the frustoconical aperture also can include a curved edge.

The emitter of the present invention includes a nanowire. The nanowire is formed from a hafnium carbide (HfC) single crystal, and at least an end portion of the hafnium carbide single crystal, from which electrons are to be emitted, is covered with hafnium oxide (HfO.sub.2). In the emitter, the thickness of the hafnium oxide may be 1 nm to 20 nm.