Method and apparatus for examining a beam of charged particles

An apparatus for examining a beam of charged particles, comprising:

• a. means for producing persistent interactions of the beam with a sample at a plurality of positions of the sample relative to the beam, in which the persistent interactions comprise beam-induced deposition of material from vapor phase onto a part of the surface of the sample, the deposited material being obtained from at least one precursor material;
• and
• b. means for deriving at least one property of the beam by analyzing the spatial distribution of the persistent interactions at the plurality of positions,
• wherein at least some of the plurality of positions of the sample are arranged at different points in the direction of propagation of the beam by adjusting the position of the sample while keeping beam optics parameters constant;
• wherein producing the persistent interactions further comprises varying one or more parameters of the beam-induced deposition of material to cause the deposition of material to become saturated with respect to a beam intensity in a core region of the beam of charged particles by performing at least one of:
• (i) increasing the intensity of the beam of charged particles;
• (ii) changing an interaction duration of the beam with the sample;
• (iii) reducing an amount of the at least one precursor material provided to the part of the surface of the sample to reduce the concentration of the at least one precursor material at the part of the surface of the sample;
• or
• (iv) depleting the precursor material in the core region of the beam.

An apparatus for examining a beam of charged particles, comprising:

• a. at least one beam optical unit, which is embodied to direct the beam onto a sample at a plurality of positions;
• b. at least one material, which is embodied to produce persistent interactions of the beam with the sample, in which the persistent interactions comprise beam-induced deposition of material from vapor phase onto a part of the surface of the sample, the deposited material being obtained from at least one precursor material;
• and
• c. at least one analyzer, which is embodied to derive at least one property of the beam by analyzing the spatial distribution of the persistent interactions at the plurality of positions,
• wherein at least some of the plurality of positions of the sample are arranged at different points in the direction of propagation of the beam by adjusting the position of the sample while keeping beam optics parameters constant;
• wherein the apparatus is configured to produce the persistent interactions by varying one or more parameters of the beam-induced deposition of material to cause the deposition of material to become saturated with respect to a beam intensity in a core region of the beam of charged particles in a way that includes at least one of:
• (i) increase the intensity of the beam of charged particles;
• (ii) change an interaction duration of the beam with the sample;
• (iii) reduce an amount of the at least one precursor material provided to the part of the surface of the sample to reduce the concentration of the at least one precursor material at the part of the surface of the sample;
• or
• (iv) deplete the precursor material in the core region of the beam.

A method for examining a beam of charged particles, the method comprising:

• producing persistent interactions of the beam with a sample at a plurality of positions of the sample relative to the beam, wherein the persistent interactions comprise beam-induced etching of a part of the surface of the sample using at least one etching gas, and varying one or more parameters of the beam-induced etching to cause the beam-induced etching of the part of the surface of the sample to become saturated with respect to a beam intensity in a core region of the beam of charged particles;
• and
• deriving at least one property of the beam by analyzing the spatial distribution of the persistent interactions at the plurality of positions;
• wherein at least some of the plurality of positions of the sample are arranged at different points in the direction of propagation of the beam by adjusting the position of the sample while keeping beam optics parameters constant.

A method for examining a beam of charged particles, the method comprising:

• producing persistent interactions of the beam with a sample at a plurality of positions of the sample relative to the beam, in which the persistent interactions comprise at least one of (i) direct modification of a part of the surface of the sample to cause persistent changes at the part of the surface of the sample, (ii) beam-induced deposition of material from vapor phase onto a part of the surface of the sample, or (iii) etching of a part of the surface of the sample using at least one etching gas;
• wherein producing the persistent interactions comprises varying one or more parameters of the persistent interactions to cause the persistent interactions of the beam with the sample to become saturated with respect to a beam intensity in a core region of the beam of charged particles;
• and
• deriving at least one property of the beam by analyzing the spatial distribution of the persistent interactions at the plurality of positions;
• wherein at least some of the plurality of positions of the sample are arranged at different points in the direction of propagation of the beam by adjusting the position of the sample while keeping beam optics parameters constant.