Patent ID: 11927549
Assignee: KLA CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 0:
1. An inspection system comprising:
an array of electron beam columns, each comprising an electron source configured to emit electrons toward a stage;
a first permanent magnet array configured to condense the electrons from each electron source into an array of electron beams, wherein the first permanent magnet array is arranged at a first end of the array of electron beam columns; and
a plurality of shielding plates extending across the array of electron beam columns downstream of the first permanent magnet array in a direction of electron emission;
wherein the plurality of shielding plates each comprise a plurality of apertures and have a thickness between 1 μm and 1 mm, and the array of electron beams pass through the plurality of apertures; and
whereby the plurality of shielding plates reduce stray magnetic field in a radial direction of the array of electron beams.