Charged particle generating apparatus

A charged particle generating apparatus comprising:

• a first electrode operable to discharge charged particles;
• a second electrode operable to generate an electric field to attract said charged particles from said first electrode;
• a voltage source operable to generate an attraction voltage to generate said electric field between said first electrode and said second electrode;
• an electrode current measurement unit operable to measure electrode current flowing through said second electrode in accordance with an amount of said charged particles discharged from said first electrode to said second electrode;
• and
• a power supply shut-down circuit operable to terminate said generation of said attraction voltage when said electrode current measured by said electrode current measurement unit is detected to be less than a predetermined value.

A charged particle generating apparatus comprising:

• a first electrode operable to discharge charged particles;
• a current source operable to supply a current to said first electrode for heating said first electrode;
• a heat current measurement unit operable to measure said current for heating said first electrode;
• a second electrode operable to generate an electric field to attract said charged particles from said first electrode;
• a voltage source operable to generate an attraction voltage for generation of said electric field between said first electrode and said second electrode;
• an electrode current measurement unit operable to generate electrode current flowing through said second electrode in accordance with an amount of said charged particles discharged from said first electrode to said second electrode;
• and a power supply shut-down circuit operable to terminate at least one of said supply of said current for heating said first electrode and said generation of said attraction voltage based on at least one of a first determination that said current measured by said heat current measurement unit is less than a first predetermined value and a second determination that said electrode current measured by said electrode current measurement unit is less than a second predetermined value.

An apparatus for irradiating charged particles on a sample to measure a condition of said sample by detecting reflection of secondary electrons radiated from said sample after said charged particles are irradiated on said sample, said apparatus, comprising:

• a charged particle generating apparatus operable to irradiate said charged particles on said sample;
• a focussing unit operable to focus said charged particles irradiated from said charged particle generating apparatus onto said sample;
• a signal generator operable to receive said secondary electrons radiated from said sample and outputting a secondary electron detecting signal corresponding to an amount of said secondary electrons;
• and
• a measurement unit operable to measure said condition of said sample based on said secondary electron detecting signal;
• wherein said charged particle generating apparatus comprises:
• a first electrode operable to discharge charged particles;
• a current source supplying a current to said first electrode for heating said first electrode;
• a heat current measurement unit operable to measure said current for heating said first electrode;
• a second electrode operable to generate an electric field to attract said charged particles from said first electrode;
• a voltage source operable to generate an attraction voltage for generation of said electric field between said first electrode and said second electrode;
• an electrode current measurement unit operable to measure electrode current flowing through said second electrode in accordance with an amount of said charged particles discharged from said first electrode to said second electrode;
• and
• a power supply shut-down circuit operable to terminate at least one of said supply of said current for heating said first electrode and said generation of said attraction voltage based on at least one of a first determination that said current measured by said heat current measurement unit is less than a first predetermined value and a second determination that said electrode current measured by said electrode current measurement unit is less than a second predetermined value.

A charged particle generating apparatus comprising:

• a first electrode operable to discharge charged particles;
• a current source operable to supply a current to said first electrode for heating said first electrode;
• a heat current measurement unit operable to measure said current for heating said first electrode;
• a second electrode operable to generate an electric field to attract said charged particles from said first electrode;
• a voltage source operable to generate an attraction voltage to generate said electric field between said first electrode and said second electrode;
• an electrode current measurement unit operable to measure electrode current flowing through said second electrode in accordance with an amount of said charged particles discharged from said first electrode to said second electrode;
• and
• a power supply shut-down circuit operable to terminate at least one of said supply of said current for heating said first electrode and said generation of said attraction voltage when said power supply shut-down circuit determines at least one of a first connection between said first electrode and said current source is one of a broken connection and an incomplete connection based on said current measured by said heat current measurement unit, and a second connection between said second electrode and said voltage source is one of a broken connection and an incomplete connection based on said electrode current measured by said electrode current measurement unit.