Patent ID: 8859992
Filing Date: 2014-10-14
Classification: H01J

Abstract:
1. A charged particle beam device comprising: beam generating apparatus for generating a focussed charged particle beam; a specimen chamber for containing a specimen to interact with the beam in a gaseous environment; a pressure limiting aperture for providing partial gaseous isolation of the specimen chamber from the beam generating apparatus, the beam generating apparatus having a lens for focussing the beam which lens includes an intermediate chamber, wherein the device further includes a gas inlet for enabling gas to be supplied to the intermediate chamber to set up a flow of gas from the lens towards the specimen, thereby to prevent material released from the specimen from impinging on the pressure limiting aperture; and wherein the device further comprises a valve for allowing gas to enter the specimen chamber and a system control for adjusting said valve, the system control being configured to adjust the valve to maintain in the specimen chamber an average gas pressure in a range of 1 Pa to 400 Pa.