Charged particle beam device, defect observation device, and management server
View Patent ↗Provided is a charged particle beam device that prevents the increase in processing trouble caused by deterioration in the reviewing performance (e.g., overlooking of defects) by detecting an operation abnormality affecting the performance of the device or a possibility of such an abnormality in the middle of a processing sequence of a sample and giving a feedback in real time. In each processing step of the charged particle beam device, monitoring items representing the operating status of the device (control status of the electron beam, an offset amount at the time of wafer positioning, a defect coordinate error offset amount, etc.) are monitored during the processing sequence of a sample and stored as history information. In the middle of the processing sequence, a comparative judgment between the value of each monitoring item and the past history information corresponding to the monitoring item is made according to preset judgment criteria. When the width of fluctuation from the past history information deviates from a reference range, an alert is issued.
1. A charged particle beam device which executes a sequence of automatically acquiring images of multiple parts of a sample mounted on a sample table by irradiating the multiple parts with a primary charged particle beam, comprising:
imaging means which acquires the images; and
control means which controls the imaging means,
wherein the control means compares a value of a monitoring item of the imaging means set or calculated at the time of the execution of the sequence with history information on the monitoring item and thereby detects an occurrence of a detection error of a defect coordinate or an oversight of a defect by obtaining fluctuation of the monitoring item with respect to the history information.
2. The charged particle beam device according to claim 1 , comprising display means which displays temporal transition of the fluctuation.
3. The charged particle beam device according to claim 2 , wherein an alert is issued on the display means when the width of the fluctuation exceeds a prescribed threshold value.
4. The charged particle beam device according to claim 3 , wherein a setting screen to be used for setting the method of the comparison with the threshold value or the history information is displayed on the display means.
5. The charged particle beam device according to claim 1 , comprising a sample stage which moves the sample table,
wherein a control parameter related to alignment of the irradiating position of the primary charged particle beam is used as the monitoring item.
6. The charged particle beam device according to claim 5 , wherein the amount of offset or rotation with respect to a reference position of the primary charged particle beam irradiating position is used as the monitoring item.
7. The charged particle beam device according to claim 1 , wherein:
the imaging means executes two-step imaging for the acquisition of the image, in which an image is captured at a first magnification ratio and then the visual field center for imaging at a second magnification ratio higher than the first magnification ratio is determined by using the image captured at the first magnification ratio, and
a control parameter related to the imaging at the first magnification ratio or the second magnification ratio is used as the monitoring item.
8. The charged particle beam device according to claim 7 , wherein automatic focusing accuracy in the imaging or a success rate of the imaging at the second magnification ratio is used as the monitoring item.
9. A defect observation device which executes a sequence of automatically acquiring an image of a defect position of a prescribed sample by irradiating the defect position with a primary charged particle beam by using defect position information on the sample acquired by an external inspection device, comprising:
imaging means which acquires the image; and
control means which controls the imaging means,
wherein the control means compares a value of a monitoring item of the imaging means set or calculated at the time of the execution of the sequence with history information on the monitoring item and thereby detects an occurrence of a detection error of a defect coordinate or an oversight of a defect by obtaining fluctuation of the monitoring item with respect to the history information.
10. The defect observation device according to claim 9 , comprising storage means which stores recipe information to be used for controlling the execution of the sequence,
wherein the control means executes the calculation of the fluctuation after setting values of monitoring items based on the recipe information.
11. The defect observation device according to claim 9 , comprising sample storage means which stores a plurality of samples,
wherein the calculation of the fluctuation is executed after the sequence for one sample stored in the sample storage means is finished.
12. A management server which is capable of being connected via a communication line to a charged particle beam device that executes a sequence of automatically acquiring images of multiple parts of a sample conveyed from sample storage means storing a plurality of samples by irradiating the multiple parts with a primary charged particle beam, comprising:
storage means which stores history information on a monitoring item of the charged particle beam device set or calculated at the time of the execution of the sequence; and
calculation means which compares a value of the monitoring item set or calculated for the sample with the history information and thereby detects an occurrence of a detection error of a defect coordinate or an oversight of a defect by obtaining fluctuation of the monitoring item with respect to the history information.