Secondary electron optics and detection device

A secondary charged particle detection system for a charged particle beam device, the detection system comprising:

• a beam splitter for separating a primary beam and a secondary beam formed upon impact on a specimen;
• a beam bender for deflecting the secondary beam;
• a focusing lens for focusing the secondary beam;
• a detection element for detecting the secondary beam particles;
• and
• three deflectors, wherein at least a first deflector of the three deflectors is provided between the beam bender and the focusing lens, at least a second deflector of the three deflectors is provided between the focusing lens and the detection element, at least a third deflector of the three deflectors is provided between the beam splitter and the detection element, and wherein at least the third deflector is provided between the beam bender and the focusing lens.

A charged particle beam device, comprising:

• a secondary charged particle detection system, the detection system comprising:
• a beam splitter for separating a primary beam and a secondary beam formed upon impact on a specimen;
• a beam bender for deflecting the secondary beam;
• a focusing lens for focusing the secondary beam;
• a detection element for detecting secondary beam particles;
• and
• three deflectors, wherein at least a first deflector of the three deflectors is provided between the beam bender and the focusing lens, at least a second deflector of the three deflectors is provided between the focusing lens and the detection element, at least a third deflector of the three deflectors is provided between the beam splitter and the detection element, and wherein at least the third deflector is provided between the beam splitter and the beam bender.

A method of detection of secondary charged particles in a charged particle beam device, the method comprising:

• separating a secondary beam from a primary beam by means of a beam separator;
• deflecting the separated secondary beam by means of a beam bender;
• and
• focusing the secondary beam on a detection element by means of a focusing lens, wherein the secondary beam is deflected by at least a first deflector provided between the beam bender and the focusing lens, at least a second deflector provided between the focusing lens and the detection element, and at least a third deflector provided between the beam splitter and the detection element.

A secondary charged particle detection system for a charged particle beam device, the detection system comprising:

• a beam splitter for separating a primary beam and a secondary beam formed upon impact on a specimen;
• a beam bender for deflecting the secondary beam;
• a focusing lens for focusing the secondary beam;
• a detection element for detecting the secondary beam particles;
• and
• three deflectors, wherein at least a first deflector of the three deflectors is provided between the beam bender and the focusing lens, at least a second deflector of the three deflectors is provided between the focusing lens and the detection element, at least a third deflector of the three deflectors is provided between the beam splitter and the detection element, and wherein either the second deflector is an octopole or wherein the first deflector and the second deflector are a quadrupole or higher order elements and are rotated with respect to each other by 45°.