Optical inspection tools featuring parallel post-inspection analysis
View Patent ↗An optical inspection tool can automatically perform analysis/operations after the tool has generated data identifying defects (e.g. a defect list) from an inspection run of an object such as a semiconductor wafer. The tool can decouple post-inspection tasks from performing inspection runs so that one or more post-inspection tasks are performed on defect data from a previous inspection run while another inspection run is in progress. This can significantly improve the throughput of the tool when multiple inspections are performed, since the inspection run time effectively is shortened to include only the time the tool is actually used to acquire defect data. One or more post-inspection tasks can be performed, including, but not limited to, merging inspection runs, removing duplicate defects, removing straight-line false alarms, and characterizing defects.
1. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises attempting to identify duplicated defects from the data and removing identified duplicated defects from the data.
2. The method set forth in claim 1 , wherein the at least one post-inspection processing task further comprises performing an automatic defect classification operation on at least one of the defects identified in the data.
3. The method set forth in claim 1 , wherein during a first of the inspection runs, a first one of the wafers is inspected, and during a second of the inspection runs, a second one of the wafers different from the first wafer is inspected.
4. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises merging a plurality of inspection runs corresponding to one of the wafers.
5. The method set forth in claim 4 , wherein two of the inspection runs corresponding to one of the wafers are merged.
6. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises attempting to identify at least one cluster of defects from the data.
7. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises performing a defect signature analysis on at least one of the defects identified in the data.
8. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises removing an indication of a straight-line false alarm.
9. The method set forth in claim 8 , wherein removing an indication of a straight-line false alarm comprises:
projecting indicated defects from a plurality of dies into a defect list identifying each of the indicated defects by its location in a single representative die;
in the representative die, identifying a plurality of narrow regions extending between any two opposite edges of the representative die; and
for each of the narrow regions, testing whether a number of indicated defects in the narrow region exceeds a predetermined threshold, and if so, deleting all indications of defects in the narrow region from the defect list.
10. A method, comprising:
(a) performing a plurality of inspection runs to inspect semiconductor wafers, each of the inspection runs comprising:
(i) illuminating one of the wafers via at least one illumination source,
(ii) forming an image of at least a portion of the illuminated wafer, and
(iii) analyzing the image to produce data identifying a plurality of defects; and
(b) during at least one of the inspection runs, performing at least one post-inspection processing task on a portion of the data, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises calculating a defect density for a plurality of areas on one of the wafers.
11. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object; and
a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises attempting to identify duplicated defects from the data identifying the defects and remove said duplicated defects from the data identifying the defects.
12. The system set forth in claim 11 , wherein the at least one post-inspection processing task comprises performing an automatic defect classification operation on at least one of the identified defects.
13. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object; and
a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises merging a plurality of inspection runs of corresponding the object.
14. The inspection system set forth in claim 13 , wherein two of the inspection runs corresponding to the object are merged.
15. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object and a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during gin an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises attempting to identify at least one cluster of defects within the identified defects.
16. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object and a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises performing a defect signature analysis on at least one of the identified defects.
17. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object; and
a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises removing a straight-line false alarm.
18. The system set forth in claim 17 , wherein removing a straight-line false alarm comprises:
projecting indicated defects from a plurality of dies into a defect list identifying each of the indicated defects by its location in a single representative die;
in the representative die, identifying a plurality of narrow regions extending between any two opposite edges of the representative die; and
for each of the narrow regions, testing whether the a number of indicated defects in the narrow region exceeds a predetermined threshold, and if so, deleting all indications of defects in the narrow region from the defect list.
19. A system, comprising:
at least one illumination source;
an imaging system configured to form an image of at least a portion of an object at a focal plane;
a transporter configured to impart relative motion between the object and the focal plane so that the portion of the object that is in view of the focal plane can be varied;
at least one detector configured to receive light comprising the image of the object and provide data representing the image of the object; and
a control system configured to:
(i) control the illumination source, the transporter, and the at least one detector during a plurality of inspection runs,
(ii) analyze the data from the at least one detector representing the image of the object and produce data identifying a plurality of defects, and
(iii) during at least one of the inspection runs, perform at least one post-inspection processing task on a portion of the data identifying the defects, the portion produced during an inspection run performed prior to the at least one of the inspection runs, wherein the at least one post-inspection processing task comprises calculating a defect density for a plurality of areas on the object wafer.