Particle beam apparatus and method for operating a particle beam apparatus

A method for operating a particle beam apparatus having a column that includes a particle-beam optical system adapted to expose a desired pattern in a vacuum sample chamber during an exposure operation, comprising:

• during a cleaning operation for cleaning the column and/or the vacuum sample chamber, feeding a regulable gas stream, having a photodissociatable gas, via a gas-feed system to the column and/or the vacuum sample chamber;
• during the cleaning operation, photodissociating the gas with the aid of a plurality of light sources distributed spatially in the column and/or in the vacuum sample chamber, by selectively switching individual light sources on and off selectively with respect to time via a control unit connected to the light sources;
• generating, by an ozone generator from an oxygen reservoir, ozone as the photodissociatable gas, the ozone generator and the oxygen reservoir being located outside of the column, and feeding the ozone to the column via the gas-feed system, to form, by interaction between radiation emitted by the light sources and the ozone, oxygen radicals as photodissociation products that react with contaminants to form degradation products that are able to be pumped off;
• and
• selectively switching on and off at least one light source with respect to time during the cleaning operation independently of selectively switching on and off at least one other light source with respect to time during the cleaning operation.

A particle beam apparatus, comprising:

• a column including a particle-beam optical system adapted to generate a particle beam to expose a desired pattern in a vacuum sample chamber during an exposure operation;
• a gas-feed system adapted to feed a regulable gas stream having a photodissociatable gas to the column and/or the vacuum sample chamber during a cleaning operation;
• a plurality of light sources distributed spatially in the column and/or in the vacuum sample chamber and adapted to photodissociate the gas during the cleaning operation;
• a control unit connected to the light sources and adapted to selectively switch on and off individual light sources with respect to time during the cleaning operation;
• and
• outside of the column, an oxygen reservoir and an ozone generator adapted to generate ozone from the oxygen reservoir as the photodissociatable gas and to feed the ozone to the column via the gas-feed system;
• wherein, by interaction between radiation emitted by the light sources and the ozone, oxygen radicals result as photodissociation products that react with contaminants to form degradation products that are able to be pumped off;
• wherein the control unit is adapted to selectively switch on and off at least one light source with respect to time during the cleaning operation independently of selectively switching on and off at least one other light source with respect to time during the cleaning operation;
• and
• wherein the particle beam apparatus is adapted to perform a method that includes:
• during the cleaning operation for cleaning the column and/or the vacuum sample chamber, feeding the regulable gas stream, having the photodissociatable gas, via the gas-feed system to the column and/or the vacuum sample chamber;
• and
• during the cleaning operation, photodissociating the gas with the aid of the plurality of light sources distributed spatially in the column and/or in the vacuum sample chamber, by selectively switching individual light sources on and off selectively with respect to time via the control unit connected to the light sources.