Metrology system of fine pattern for process control by charged particle beam
The present invention provides a pattern inspection technique that enables measurement and inspection of a fine pattern by a charged particle beam to be performed with high throughput. A metrology system of fine pattern according to the pattern inspection technique has: a the column that includes a charged particle source, an electron optics for scanning a desired observation area on a sample with a charged particle beam emitted from the charged particle source, and a detector for detecting charged particles generated secondarily from the sample scanned by the charged particle beam; information processing means for measuring information about geometry of a pattern formed on the sample based on information on the intensity of the charged particles obtained by the detector; and a sample introduction unit for introducing the sample into the inside of the column; wherein a charge neutralizer unit for generating ions and charge neutralizing the sample with the ions and surface potential measuring means for measuring a surface potential of the sample surface are provided on a path that is inside the sample introduction unit and transports the sample to the column.
1. A metrology system of fine pattern for process control by charged particle beam, comprising:
a column that includes a charged particle source, an electron optics for scanning a desired observation area on a sample with a charged particle beam emitted from the charged particle source, and a detector for detecting the charged particles generated secondarily from the sample scanned by the charged particle beam;
information processing means for measuring information about geometry of a pattern formed on the sample based on information on the intensity of the charged particles obtained by the detector; and
a sample introduction unit for introducing the sample into the inside of the column,
wherein a charge neutralizer unit for generating ions and charge neutralizing the sample with the ions and surface potential measuring means for measuring a surface potential of the sample surface are provided on a path that is inside the sample introduction unit and transports the sample to the column, and
wherein the metrology system is configured to correct focusing by feeding back to a retarding voltage a value of the surface potential of the sample measured by the surface potential measuring means before transportation of the sample to the column.
2. The metrology system of fine pattern for process control by charged particle beam according to claim 1 ,
wherein the charge neutralizer unit has a charge neutralizer for generating ions by corona discharge and a rotation stage allowing the sample to be placed and held thereon and capable of rotation with the sample, and
the charge neutralizer is installed to place above the rotation stage.
3. The metrology system of fine pattern for process control by charged particle beam according to claim 1 ,
wherein mechanical arm means for wafer transportation that is inside the sample introduction unit and transports the sample to the rotation stage and the surface potential measuring means are provided.
4. The metrology system of fine pattern for process control by charged particle beam according to claim 2 ,
wherein the charge neutralizer unit is installed at a position whose distance to the sample mount plane of the rotation stage is not more than one half times the radius of the wafer.