Charged particle beam devices

摘要

In a charged particle beam device, such as an electron microscope, a beam generating apparatus generates a focussed charged particle beam e− that is incident on a specimen in a specimen chamber which holds the specimen in a gaseous environment. A pressure limiting aperture provides partial gaseous isolation of the specimen chamber from the beam generating means, and is located in a lens of the latter. The device includes a conduit, such as an intermediate chamber in the lens, through which, in use, gas is supplied to set up a flow of gas from the region of the lens towards the specimen, thereby to prevent material released from the specimen from impinging on the pressure limiting aperture, to prevent contamination of the latter. The device can be used in a method of scanning a specimen with a charged particle beam, for example in a method of electron microscopy.

主权项

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.