Method and apparatus for positioning a focused beam on an integrated circuit

Apparatus for accurately positioning focused electromagnetic energy on a semiconductor surface comprising

• a beam source of electromagnetic energy,
• a movable first platform member,
• means for moving said first platform member in a first direction parallel to a movement plane,
• a movable second platform member supported by and movable on said first platform member,
• means for moving said second platform member in a second direction parallel to said movement plane,
• a rotatable mirror assembly supported by said second platform member,
• an optical system supported by said second platform member for focusing an energy beam incident thereon onto said semiconductor surface,
• a beam directing assembly for directing the beam source of electromagnetic energy onto said rotatable mirror assembly,
• said rotatable mirror assembly deflecting the energy beam incident thereon from a direction substantially parallel to the movement plane to a direction wherein said deflected beam passes through the optical system for focusing the beam onto said semiconductor surface, and
• a control processing means for controlling the position of the first and second platform members and of the rotatable mirror assembly for accurately positioning the beam source onto the semiconductor surface as a cell of focused energy.

Apparatus for accurately positioning focused energy on a semiconductor surface comprising

• a beam source of electromagnetic energy,
• a movable first platform member,
• means for moving said first platform member in a first direction parallel to a movement plane,
• a movable second platform member supported by and movable on said first platform member,
• means for moving said second platform member in a second direction parallel to said movement plane,
• a first and a second rotatable mirror means supported by said second platform member,
• an optical system supported by said second platform member for focusing an energy beam incident thereon on said semiconductor surface,
• means for directing said beam source of electromagnetic energy onto said first mirror means,
• said first and second mirror means having an operational interrelationship for deflecting said incident energy beam from a direction substantially parallel to said movement plane to a direction wherein said deflected beam passes through said optical system for focusing said beam on said semiconductor surface, and
• a control means for controlling the position of said first and second platform members and of said first and second mirror means for accurately positioning said beam source on said semiconductor surface as a cell of focused energy.

In an apparatus for accurately positioning a focused energy beam on a semiconductor surface, said apparatus comprising

• a beam source of electromagnetic energy,
• a platform assembly movable along first and second directions parallel to a movement plane,
• a rotatable mirror assembly supported by said platform assembly,
• an optical system supported by said platform assembly for focusing an energy beam incident thereon onto said semiconductor surface,
• means for directing said beam source of electromagnetic energy onto said mirror means,
• said rotatable mirror assembly deflecting said directed beam source to a direction wherein said mirror assembly deflected beam passes through said optical system and is focused onto said semiconductor surface, and
• a control means for controlling the position of the platform assembly and said mirror assembly for accurately positioning said beam source as a focused cell on said semiconductor surface,
• a method of accurately calibrating said rotatable mirror assembly comprising the steps of:
• positioning a measurement surface having defined features in the plane of focus of said optical system,
• measuring at least one feature of said measurement surface by moving said platform assembly while maintaining said rotatable mirror means in a fixed position relative to the optical system,
• measuring said at least one feature of the measurement surface by moving said rotatable mirror assembly while maintaining said platform assembly in a stationary condition, and
• comparing said platform assembly originated measurement with said rotatable mirror assembly originated measurement for determining the calibration of said rotatable mirror assembly.