Detector objective for particle beam apparatus

US4831266A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Juergen Frosien · Ottobrunn, DE
• Hans-Peter Feuerbaum · Hersbruck, DE

Key dates

• Filing date: Dec 8, 1987
• Grant date: May 16, 1989
• Expiry date: Dec 8, 2007

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J2237/24507
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A detector objective forms a component of an electron-optical column of a scanning electron microscope, the detector objective being composed of an asymmetrical magnetic lens, an electrostatic immersion lens generating a substantially rotationally symmetrical field, and an annular detector disposed immediately above the magnetic lens body. An electrode of the electrostatic immersion lens is formed as a truncated cone and is arranged in insulated fashion in an upper pole piece of the magnetic lens. The lower pole piece forms the second electrode of the immersion lens. The first and second electrodes are charged with potentials that establish an electrical field for decelerating the primary electrons, the electrical field overlying the focusing magnetic field.