Patent ID: 8530837

Claim:
A charged particle beam device for inspecting a specimen, comprising a charged particle beam source adapted to generate a primary charged particle beam; an objective lens device adapted to direct the primary charged particle beam onto the specimen; a retarding field device adapted to accelerate secondary charged particles starting from the specimen, wherein a first group of the secondary charged particles comprises secondary charged particles starting from the specimen with high starting angles, and a second group of the secondary charged particles comprises secondary charged particles starting from the specimen with low starting angles; a first detector device, comprising at least two detector segments for detecting secondary particles, wherein the first detector device is configured to detect the second group of secondary charged particles, and wherein the first detector device has an opening for letting pass the first group of secondary charged particles or an opening configured for having at least one second detector device provided in the opening; wherein the objective lens device is adapted such that particles with different starting angles from the specimen exhibit crossovers at substantially the same distance from the specimen, forming a common crossover, and a first aperture located between the objective lens and the detector, having an opening with a diameter equal to or smaller than the central opening in the detector device, and which is provided in a position which fulfills at least one of the following properties: (i) it is in the vicinity of the common crossover, (ii) it is at a position where stray particles exhibit a maximum spread.