Beam blanker for interrupting a beam of charged particles

Beam blanker for interrupting a beam of charged particles, the beam blanker having an axis along which charged particles propagate before entering the beam blanker, the beam blanker comprising means for generating an electric field perpendicular to said axis, the electric field for deflecting the charged particles, and an aperture in a diaphragm, the aperture transmitting the beam when the beam is not interrupted and the diaphragm stopping the beam when the beam is interrupted, characterized in that the electric field is generated by a resonant structure with a resonant frequency f, the resonant structure equipped to generate an electric field that sweeps the beam over the aperture, the resonant structure excited by a signal supplied by an electrical circuit comprising a photoreceptor, as a result of which the beam is transmitted through the aperture twice per period of the frequency f.

Beam blanker for interrupting a beam of charged particles, the beam blanker having an axis along which charged particles propagate before entering the beam blanker, the beam blanker comprising means for generating an electric field perpendicular to said axis, the electric field for deflecting the charged particles, and an aperture in a diaphragm, the aperture transmitting the beam when the beam is not interrupted and the diaphragm stopping the beam when the beam is interrupted, characterized in that the electric field is generated by a resonant structure with a resonant frequency f, the resonant structure equipped to generate an electric field that sweeps the beam over the aperture, the aperture comprising a slit or a hole with a dimension in the direction in which the beam is deflected of less than 10 μm, as a result of which the beam is transmitted through the aperture twice per period of the frequency f.

Beam blanker for interrupting a beam of charged particles, the beam blanker having an axis along which charged particles propagate before entering the beam blanker, the beam blanker comprising means for generating an electric field perpendicular to said axis, the electric field for deflecting the charged particles, and an aperture in a diaphragm, the aperture transmitting the beam when the beam is not interrupted and the diaphragm stopping the beam when the beam is interrupted, characterized in that the electric field is generated by a resonant structure with a resonant frequency f, the resonant structure equipped to generate an electric field that sweeps the beam over the aperture, the resonant structure comprising a negative resistance element, as a result of which the beam is transmitted through the aperture twice per period of the frequency f.

Particle-optical apparatus comprising a particle source for producing charged particles, one or more charged particle lenses, and a sample position of mounting a sample, the particle-optical apparatus equipped with:

• a beam blanker for interrupting a beam of charged particles, the beam blanker having an axis along which charged particles propagate before entering the beam blanker, the beam blanker comprising means for generating an electric field perpendicular to said axis, the electric field for deflecting the charged particles, and an aperture in a diaphragm, the aperture transmitting the beam when the beam is not interrupted and the diaphragm stopping the beam when the beam is interrupted, characterized in that the electric field is generated by a resonant structure with a resonant frequency f, the resonant structure equipped to generate an electric field that sweeps the beam over the aperture, the aperture comprising a slit or a hole with a dimension in the direction in which the beam is deflected of less than 10 μm, as a result of which the beam is transmitted through the aperture twice per period of the frequency f,
• the beam blanker positioned such that the beam enters the beam blanker with an energy lower than the energy with which the beam impinges on the sample.

A method of rapidly blanking a beam in a particle optical apparatus having a beam blanker including a deflector and an aperture, the beam blanker positioned along a system optical axis, comprising:

• providing a charged particle beam along the optical axis;
• providing a deflection signal from a resonator at its resonant frequency to generate an electric field perpendicular to the optical axis, the resonant structure comprising a resonant transmission line and a grounded conductor, the electric field generated between the two resonant transmission line and the grounded conductor, the resonator having a resonant frequency f and generating an electric field that sweeps the beam across a line that is in the plane of an aperture, that intersects the aperture, and that is perpendicular to the direction of deflection, and as a result, the beam crosses the line twice per period of the frequency f, the beam periodically crossing the aperture and being transmitted to a sample;
• periodically impinging the beam onto a work piece.