Apparatuses, systems, and methods for adjusting beam current using a feedback loop are provided. In some embodiments, a system may include a first anode aperture configured to measure a current of an emitted beam during inspection of a sample, wherein the first anode aperture is positioned in an environment that is configured to support a vacuum pressure of less than 3?10.sup.?10 torr and a controller including circuitry configured to cause the system to perform: generating a feedback signal when a difference between the measured current and a setpoint current exceeds a threshold value and adjusting a voltage of an extractor voltage supply based on the feedback signal during inspection of the sample such that a difference between an adjusted current of the emitted beam and the setpoint current is below the threshold value.

A method of operating a charged particle microscope comprising the following steps: Providing a specimen on a specimen holder; Using a source to produce a beam of charged particles that is subject to beam current fluctuations; Employing a beam current sensor, located between said source and specimen holder, to intercept a part of the beam and produce an intercept signal proportional to a current of the intercepted part of the beam, the beam current sensor comprising a hole arranged to pass a beam probe with an associated probe current; Scanning said probe over the specimen, thereby irradiating the specimen with a specimen current, with a dwell time associated with each scanned location on the specimen; Using a detector to detect radiation emanating from the specimen in response to irradiation by said probe, and producing an associated detector signal; Using said intercept signal as input to a compensator to suppress an effect of said current fluctuations in said detector signal,
wherein: The beam current sensor is configured as a semiconductor device with a sensing layer that is oriented toward the source, in which: Each charged particle of said intercepted part of the beam generates electron/hole pairs in said sensing layer; Generated electrons are drawn to an anode of the semiconductor device; Generated holes are drawn to a cathode of the semiconductor device, thereby producing said intercept signal.

A method for measuring an electron signal or an electron induced signal may be provided. The method may include providing a threshold number of events or a threshold event rate for a pixel on a detector. The method may include collecting from the detector the threshold number of events or determining that the threshold event rate is achieved, wherein a signal at the detector is an electron signal or an electron induced signal from a sample. The method may include modulating an intensity of an electron source directed to the sample in response.

An ion implantation apparatus includes: a multistage linear acceleration unit including a plurality of stages of high-frequency resonators and a plurality of stages of focusing lenses; a first beam measuring unit disposed in the middle of the multistage linear acceleration unit and configured to allow passage of a beam portion adjacent to a center of a beam trajectory and measure a current intensity of another beam portion blocked by an electrode body outside a vicinity of the center of the beam trajectory; a second beam measuring unit disposed downstream of the multistage linear acceleration unit and configured to measure a current intensity of an ion beam exiting from the multistage linear acceleration unit; and a control device configured to adjust a control parameter of the plurality of stages of focusing lenses based on measurement results of the first and second beam measuring units.

In one embodiment, a multi charged particle beam writing apparatus includes an aperture plate having a plurality of holes to form multiple beams, a blanking aperture array having a plurality of blankers which switch ON-OFF of corresponding respective beams among the multiple beams, a stage on which a writing target substrate is placed, an inspection aperture provided on the stage and that allows one beam among the multiple beams to pass therethrough, a deflector deflecting the multiple beams, a current detector detecting a beam current of each of the multiple beams that has passed through the inspection aperture in a case where the multiple beams are scanned on the inspection aperture, and a control computing machine that generates a beam image based on the detected beam current and detects a defect of the blanking aperture array or the aperture plate based on the beam image.

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).

A system and method for controlling an ion implantation system as a function of sampling ion beam current and uniformity thereof. The ion implantation system includes a plurality of ion beam optical elements configured to selectively steer and/or shape the ion beam as it is transported toward a workpiece, wherein the ion beam is sampled at a high frequency to provide a plurality of ion beam current samples, which are then analyzed to detect fluctuations and/or nonuniformities or unpredicted variations amongst the plurality of ion beam current samples. Beam current samples are compared against predetermined threshold levels, and/or predicted nonuniformity levels to generate a control signal when a detected nonuniformity in the plurality of ion beam current density samples exceeds a predetermined threshold. A control system can be configured to generate a control signal for interlocking the ion beam transport in the ion implantation system or for varying an input to at least one beam optical element to control variations in beam current.

An ion implantation apparatus includes a beam scanner that provides reciprocating beam scanning in a beam scanning direction, a beam measurer that measures a beam current intensity distribution in the beam scanning direction at a downstream of the beam scanner, and a controller. The controller includes a scanning waveform preparing unit that determines whether or not a measured beam current intensity distribution measured by the beam measurer with use of a given scanning waveform fits a target non-uniform dose amount distribution, and that, in a case of fitting, correlates the given scanning waveform with the target non-uniform dose amount distribution.

In one embodiment, an aperture for inspecting a multi-beam allows passage of one beam among multi-beams applied in a multi-beam writing apparatus. The aperture includes a scattering layer that is provided with a through-hole through which the one beam passes, and by which the other beams are scattered, and an absorbing layer that is provided with an opening having a diameter greater than the diameter of the through-hole and that absorbs at least some of the beams entering it.

A method for improving the productivity of a hybrid scan implanter by determining an optimum scan width is provided. A method of tuning a scanned ion beam is provided, where a desired beam current is determined to implant a workpiece with desired properties. The scanned beam is tuned utilizing a setup Faraday cup. A scan width is adjusted to obtain an optimal scan width using setup Faraday time signals. Optics are tuned for a desired flux value corresponding to a desired dosage. Uniformity of a flux distribution is controlled when the desired flux value is obtained. An angular distribution of the ion beam is further measured.