Device and method for suppressing space charge induced aberrations in charged-particle projection lithography systems

An electron gun for an electron beam illumination system, comprising:

• a cathode having an electron emission surface;
• an anode disposed proximate said cathode, said anode and cathode adapted to be connected to an acceleration-voltage power supply to provide an electric field between said cathode and said anode to accelerate electrons emitted from said cathode toward said anode;
• and
• a current-density-profile control grid disposed between said anode and said cathode and adapted to be connected to a control grid power supply, said current-density-profile control grid adapted to act in cooperation with said cathode and said anode to produce an electron beam having a non-uniform current density profile.

A charged-particle beam illumination system, comprising:

• a source of charged particles;
• a pair of electrodes adapted to be connected to an acceleration-voltage power source, said pair of electrodes being constructed and arranged to receive charged particles therebetween from said source of charged particles;
• and
• a current-density-profile control grid disposed between said pair of electrodes, said current-density-profile control grid constructed and arranged to act in cooperation with said pair of electrodes to produce a charged-particle beam having a non-uniform current density profile.

An electron beam illumination system, comprising:

• an electron gun providing a beam of electrons;
• a mask stage adapted to receive a mask and disposed in a path of said beam of electrons;
• and
• a workpiece stage adapted to receive a workpiece and disposed in a path of electrons that have passed through said mask,
• wherein said electron gun comprises:
• a cathode having an electron emission surface,
• an anode disposed proximate said cathode, said anode being adapted to be connected to an acceleration-voltage power supply capable of generating an electric field between said cathode and said anode to accelerate electrons emitted from said cathode toward said anode, and
• beam-density-profile control means for controlling the production of an electron beam having a non-uniform electron current density profile prior to reaching said mask stage.

A method of producing a micro-device, comprising:

• generating a beam of charged particles having a smaller charged-particle current density at a central region of said beam than along an outer region of said beam;
• illuminating a mask with said beam of charged particles, said mask having a pattern defined by regions which scatter charged particles more strongly than other regions of said mask;
• and
• exposing a workpiece with charged particles from said beam of charged particles.

A method of producing a micro-device, comprising:

• generating a beam of charged particles having a non-uniform charged-particle current density;
• illuminating a mask with said beam of charged particles, said mask having a pattern defined by regions which scatter charged particles more strongly than other regions of said mask;
• and
• exposing a workpiece with charged particles from said beam of charged particles,
• wherein said non-uniform charged-particle current density becomes substantially uniform during said illuminating said mask.