Charged particle assessment tool, inspection method
AssigneeASML Netherlands B.V.
InventorMarco Jan-Jaco Wieland
Life of this patent
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Abstract
A multi-beam electron-optical system for a charged-particle assessment tool, the system comprising: a plurality of control lenses, a plurality of objective lenses and a controller. The plurality of control lenses are configured to control a parameter of a respective sub-beam. The plurality of objective lenses are configured to project one of the plurality of charged-particle beams onto a sample. The controller controls the control lenses and the objective lenses so that the charged particles are incident on the sample with a desired landing energy, demagnification and/or beam opening angle.
Claims20
A multi-beam electron-optical system for a charged-particle assessment tool, the system comprising:
- a plurality of control lenses, each configured to control a parameter of a respective sub-beam of a plurality of sub-beams;
- a plurality of objective lenses, each configured to project a respective one of the plurality of sub-beams onto a sample;
- a detector configured to detect charged-particles emitted from the sample, the detector comprising a plurality of detector elements associated with respective sub-beams and the detector being spaced away from the sample by a distance away from the sample;
- and
- a controller configured to control the plurality of control lenses and the plurality of objective lenses so that the charged particles are incident on the sample with a desired landing energy and/or demagnification;
- wherein the controller is configured to control the plurality of control lenses to control the parameter of a pre-focus of the respective sub-beams so that a combined action on the respective sub-beams by the respective objective lenses and the respective control lenses determines a focus position of the respective sub-beams on the sample.
A method of projecting a plurality of sub-beams onto a sample surface by use of an objective lens array assembly comprising an array of control lenses, each control lens for controlling a parameter of a respective sub-beam;
- and an array of objective lenses, each objective lens for projecting the respective sub-beam onto a sample;
- a controller for controlling the array of control lenses and the array of objective lenses;
- and a detector for detecting charged-particles emitted from the sample, the detector comprising a plurality of detector elements associated with respective sub-beams and the detector being spaced away from the sample by a distance away from the sample;
- the method comprising:
- a) projecting the plurality of sub-beams onto a surface of a sample, the projecting using the array of objective lenses;
- b) controlling a landing energy of the plurality of sub-beams so that the plurality of sub-beams are incident on the sample with a desired landing energy and/or optimizing a demagnification of said plurality of sub-beams;
- c) controlling the array of control lenses to control the parameter comprises pre-focusing the respective sub-beams so that a combined action on the respective sub-beams by the respective objective lenses and the respective control lenses is on the sample;
- and
- d) detecting charged-particles emitted from the sample,
- wherein the controlling of the control lenses and the objective lenses is done by the controller and the detecting is done by the detector.
A replaceable module configured to be replaceable in a charged particle-optical column of a charged particle inspection tool, the replaceable module comprising:
- an objective lens array assembly comprising:
- a plurality of control lenses configured to control a parameter of a respective sub-beam of a multi-beam, the parameters comprising demagnification and/or landing energy of the multi-beam, and
- a plurality of objective lenses configured to project a respective sub-beam of the multi-beam onto a sample;
- and
- a detector configured to detect charged-particles emitted from the sample, the detector comprising a plurality of detector elements associated with respective sub-beams of the multi-beam and the detector being configured on placement of the replaceable module in an electron-optical column to be spaced away from the sample by a distance away from the sample,
- wherein the plurality of control lenses and the plurality of objective lenses are configured to be controlled so that the charged particles are incident on the sample with a desired landing energy and/or demagnification, and the plurality of control lenses are configured, on placement of the replaceable module in an electron-optical column, to be controlled to control the parameter of a pre-focus of the respective sub-beams so that a combined action on the respective sub-beams by the respective objective lenses and the respective control lenses determines a focus position of the respective sub-beams on the sample.
Dependencies are inferred from the claim text.