Charged particle detection system and multi-beamlet inspection system
First Claim
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1. A charged particle detection system, comprising:
- a first detector having an array of plural detection elements for detecting charged particles;
a first aperture plate having a first array of plural apertures to be traversed by charged particles and disposed at a first distance from the first detector;
a second aperture plate having a second array of plural apertures to be traversed by charged particles and disposed at a second distance from the first detector, the second distance being greater than the first distance; and
a voltage supply configured to supply a first electric potential to the first detector, to supply a second electric potential to the first aperture plate, and to supply a third electric potential to the second aperture plate;
wherein the apertures of the first aperture plate, the apertures of the second aperture plate and the detection elements of the first detector are substantially aligned relative to each other such that plural beamlets of charged particles can each traverse an aperture of the first aperture plate and an aperture of the second aperture plate to be incident on a detection element of the first detector; and
wherein the first electric potential, the second electric potential and the third electric potential are selected so that charged particles of the beamlets having a kinetic energy below a threshold energy cannot traverse the first array of plural apertures of the first aperture plate and are prevented from being incident on the detection elements.
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Abstract
A charged particle detection system comprises plural detection elements and a multi-aperture plate in proximity of the detection elements. Charged particle beamlets can traverse the apertures of the multi-aperture plate to be incident on the detection elements. More than one multi-aperture plate can be provided to form a stack of multi-aperture plates in proximity of the detector. A suitable electric potential supplied to the multi-aperture plate can have an energy filtering property for the plural charged particle beamlets traversing the apertures of the plate.
19 Citations
15 Claims
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1. A charged particle detection system, comprising:
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a first detector having an array of plural detection elements for detecting charged particles; a first aperture plate having a first array of plural apertures to be traversed by charged particles and disposed at a first distance from the first detector; a second aperture plate having a second array of plural apertures to be traversed by charged particles and disposed at a second distance from the first detector, the second distance being greater than the first distance; and a voltage supply configured to supply a first electric potential to the first detector, to supply a second electric potential to the first aperture plate, and to supply a third electric potential to the second aperture plate; wherein the apertures of the first aperture plate, the apertures of the second aperture plate and the detection elements of the first detector are substantially aligned relative to each other such that plural beamlets of charged particles can each traverse an aperture of the first aperture plate and an aperture of the second aperture plate to be incident on a detection element of the first detector; and wherein the first electric potential, the second electric potential and the third electric potential are selected so that charged particles of the beamlets having a kinetic energy below a threshold energy cannot traverse the first array of plural apertures of the first aperture plate and are prevented from being incident on the detection elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A multi-beamlet inspection system for inspecting a substrate, comprising:
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a charged particle detection system; a charged particle source for generating a first array of charged particle beamlets; first beam shaping optics for directing the array of charged particle beamlets onto the substrate to form an array of spots illuminated with charged particles on the substrate; and second beam shaping optics for receiving charged particles emanating from the substrate and directing the received charged particles as a second array of charged particle beamlets towards the charged particle detection system; wherein the charged particle detection system comprises; a first detector having an array of plural detection elements for detecting charged particles; a first aperture plate having a first array of plural apertures to be traversed by charged particles and disposed at a first distance from the first detector; a second aperture plate having a second array of plural apertures to be traversed by charged particles and disposed at a second distance from the first detector, the second distance being greater than the first distance; and a voltage supply configured to supply a first electric potential to the first detector, to supply a second electric potential to the first aperture plate, and to supply a third electric potential to the second aperture plate; wherein the apertures of the first aperture plate, the apertures of the second aperture plate and the detection elements of the first detector are substantially aligned relative to each other such that plural beamlets of charged particles can each traverse an aperture of the first aperture plate and an aperture of the second aperture plate to be incident on a detection element of the first detector; and wherein the first electric potential, the second electric potential and the third electric potential are selected so that charged particles of the beamlets having a kinetic energy below a threshold energy cannot traverse the first array of plural apertures of the first aperture plate and are prevented from being incident on the detection elements.
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Specification