Charged particle beam application system
View Patent ↗During the writing operation, the wafer potential is dynamically detected and corrected. By doing so, the positional accuracy of the circuit patterns written on a wafer can be improved. After a contact resistance between a wafer and a earth pin is measured, the current flowing from the wafer to the ground potential via the earth pin is measured. Then, based on the measurement result, the potential difference is given between the wafer and the ground potential.
1. A charged particle beam application system, comprising: a sample stage for holding a sample; means for irradiating charged particle beam to the sample on the sample stage; and an electrostatic chuck mounted on said sample stage,
wherein the electrostatic chuck comprises:
a dielectric having a mounting surface on which the sample is mounted;
electrodes provided in the dielectric;
a contact terminal for setting said sample to ground potential;
a variable direct current power supply and a direct current power supply electrically connected to said electrodes;
control means for controlling a voltage applied to the variable direct current power supply; and
current measuring means arranged between said contact terminal and said ground potential, and
said control means calculates said voltage applied to the variable direct current power supply based on the measurement result of the current measuring means.
2. The charged particle beam application system according to claim 1 ,
wherein a plurality of said electrodes are provided,
said variable direct current power supply and direct current power supply are connected to either of said plurality of electrodes, and
said plurality of electrodes, the variable direct current power supply and the direct current power supply form a closed circuit.
3. The charged particle beam application system according to claim 1 ,
wherein a plurality of said electrodes are provided,
said variable direct current power supply and direct current power supply are connected between the plurality of electrodes and the ground potential, and
a feedback circuit arranged between the current measuring means and said variable direct current power supply is provided as said control means.
4. The charged particle beam application system according to claim 1 ,
wherein a plurality of said electrodes are provided,
a plurality of direct current power supplies corresponding to the number of the plurality of electrodes are provided, and
said variable direct current power supply is arranged between said current measuring means and said ground potential or between said contact terminal and said current measuring means.
5. The charged particle beam application system according to claim 1 ,
wherein a plurality of said electrodes are provided,
said direct current power supply is arranged between said electrode and said ground potential, and
said variable direct current power supply is arranged between said current measuring means and said ground potential or between said contact terminal and said current measuring means.
6. The charged particle beam application system according to claim 5 ,
wherein a plurality of said electrodes and a plurality of said current measuring means are provided.
7. The charged particle beam application system according to claim 4 ,
wherein three or more contact terminals are provided.
8. A charged particle beam application system, comprising: a sample stage for holding a sample; means for irradiating charged particle beam to the sample on the sample stage; and an electrostatic chuck mounted on said sample stage,
wherein the electrostatic chuck comprises:
a dielectric having a mounting surface on which the sample is mounted;
electrodes provided in the dielectric;
a contact terminal for setting said sample to ground potential;
a variable direct current power supply and a direct current power supply electrically connected to said electrodes;
control means for controlling a voltage applied to the variable direct current power supply;
potential measuring means for measuring the potential of said sample; and
adjusting means for adjusting response speed of the sample potential, and
said control means calculates said voltage applied to the variable direct current power supply based on the measurement result of the potential measuring means.
9. The charged particle beam application system according to claim 8 ,
wherein said adjusting means is electric resistance provided on a path between said contact terminal and said ground potential.
10. The charged particle beam application system according to claim 9 ,
wherein said adjusting means is a RC circuit arranged between said electrode and said ground potential.
11. The charged particle beam application system according to claim 10 ,
wherein a resistor and a capacitor of said RC circuit are arranged in parallel to said variable direct current power supply and said electrode.
12. A charged particle beam application system, comprising:
a charged particle gun;
a lens for focusing charged particles emitted from said charged particle gun on a sample;
a stage which can be moved during a process for the sample; and
an electrostatic chuck having a sample holding member made of a dielectric on said stage, a ground electrode in contact with the sample mounted on said holding member, and a chucking electrode which faces to said ground electrode with interposing said dielectric therebetween, said electrostatic chuck being for generating electrostatic force between said ground electrode and said chucking electrode to chuck said sample to said holding member by this electrostatic force,
wherein a mark for calibration adjacent to said sample, means for detecting a relative position of the irradiated charged particle beam to said sample or said mark for calibration, and a direct current power supply for adjusting potential of said sample between said ground electrode and the ground potential are provided.