DEFECT ESTIMATION DEVICE AND METHOD AND INSPECTION SYSTEM AND METHOD

• US 20110188734A1
• Filed: 01/31/2011
• Published: 08/04/2011
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Original Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Inventors: Abe, Takayuki, TSUCHIYA, Hideo
• Granted Patent: US 8,737,676 B2
• Time in Patent Office: Days
• US Class Current: 382/149
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation

Abstract

Acquired mask data of a defect portion is sent to a simulated repair circuit 300 to be simulated. The simulation of the acquired mask data 204 is returned to the mask inspection results 205 and thereafter sent to a wafer transfer simulator 400 along with a reference image at the corresponding portion. A wafer transfer image estimated by the wafer transfer simulator 400 is sent to a comparing circuit 301. When it is determined that there is a defect in the comparing circuit 301, the coordinates and the wafer transfer image which is a basis for the defect determination are stored as transfer image inspection results 206. The mask inspection results 205 and the transfer image inspection result 206 are then sent to the review device 500.

Claims

1. A defect estimation device comprising:

an estimation part which obtains an optical image of a pattern formed on a mask and a reference image and estimates, from these images, each pattern image of the patterns transferred to a substrate;

a comparison part which compares the pattern images with each other and when a difference exceeds at least one of the threshold values, determines that there is a defect;

a simulated repair part which simulates a repair to the optical image at a portion determined as defective by the comparison,

wherein, the simulated optical image is sent to the estimation part.

2. A defect estimation device comprising:

a first estimation part which obtains an optical image of a pattern formed on a mask and a reference image and estimates, from these images, each first pattern image of the patterns transferred to a substrate by a lithography process;

a first comparison part which compares the first pattern images with each other and when a difference exceeds at least one of the threshold values, determines that there is a defect;

a simulated repair part which simulates a repair to the optical image at a portion determined as defective by the comparison;

a second estimation part which estimates each second pattern image of the patterns, transferred onto the substrate, from the reference image and the simulated optical image,

wherein in the second pattern image, the lithography process is more advanced than that in the first pattern image.

3. A defect estimation method comprising:

obtaining an optical image of a pattern formed on a mask and a reference image, estimating, from these images, each first pattern image of the patterns transferred to a substrate and comparing the first pattern images with each other;

simulating the optical image at a portion determined as defective by the comparison and

estimating, after the simulated repair, each second pattern image from the reference image and the simulated optical image.

4. An inspection device, which irradiates light on to a mask formed with a pattern, forming an image of the mask on an image sensor through an optical system and determining the presence of a defect, characterized by comprising:

an optical image acquisition part which obtains an optical image of the mask from the image sensor;

an estimation part which estimates each pattern image of the patterns, transferred to a substrate, from a reference image as a reference of the determination and the optical image;

a comparison part which compares the pattern images with each other and when a difference exceeds at least one of the threshold values, determines that there is a defect;

a simulated repair part which simulates a repair to the optical image at a portion determined as defective by the comparison,

wherein the simulated optical image is sent to the estimation part.

5. An inspection device, which irradiates light to a mask formed with a pattern, forming an image of the mask on an image sensor through an optical system and determines the presence of a defect, comprising:

an optical image acquisition part which obtains an optical image of the mask from the image sensor;

a first estimation part which estimates, from a reference image as a reference of the determination and the optical image, each first pattern image of the patterns transferred to a substrate by a lithography process;

a first comparison part which compares the first pattern images with each other and when a difference exceeds at least one of the threshold values, determines that there is a defect;

a simulated repair part which simulates a repair to the optical image at a portion determined as defective by the comparison;

a second estimation part which estimates each second pattern image of the patterns, transferred onto the substrate, from the reference image and the simulated optical image, wherein in the second pattern image, the lithography process is more advanced than that in the first pattern image.

6. An inspection device, which irradiates light to a sample formed with a pattern, forming an image of the sample on an image sensor through an optical system, and determines the presence of a defect, comprising:

an optical image acquisition part which obtains an optical image of the sample from the image sensor;

a first comparison part which compares the optical image with a reference image as a reference of the determination and, when a difference exceeds at least one of the threshold values, determines that there is a defect;

a transfer image estimation part which estimates by simulation an optical image obtained when each pattern of an optical image on the sample and the reference image is transferred by a transfer device and

a second comparison part which compares each of the transfer images and when a difference exceeds at least one of the threshold values, determines that there is a defect.

7. The inspection device according to claim 6, characterized by further comprising an output part, which outputs information from the first and second comparison parts to a review device or to a review screen for reviewing the information from the first and second comparison parts.

8. The inspection device according to claim 7, characterized in that the information from the first comparison part contains an optical image determined as defective and a coordinate of the defect, and the information from the second comparison part contains a transfer image of the optical image determined as defective and the coordinates of the defect.

9. An inspection device, which irradiates light to a sample formed with a pattern, forming an image of the sample on an image sensor through an optical system and determines the presence of a defect, characterized by comprising:

an optical image acquisition part which obtains an optical image of the sample from the image sensor;

a first comparison part which compares the optical image with a reference image as a reference of the determination and when a difference exceeds at least one of the threshold values, determines that there is a defect;

a simulated repair part which obtains the optical image determined as defective by the first comparison part and simulates a repair to the defect;

a transfer image estimation part which estimates a transfer image of the optical image simulated by the simulated repair part and a transfer image of the reference image by simulation and

a second comparison part which compares each of the transfer images and when a difference exceeds at least one of the threshold values, determines that there is a defect.

10. The inspection device according to claim 9 characterized by further comprising an output part, which outputs information from the first and second comparison parts to a review device or to a review screen for reviewing the information from the first and second comparison parts.

11. The inspection device according to claim 10, characterized in that the information from the first comparison part includes an optical image determined as a defect and a coordinate of the defect and the information from the second comparison part includes a transfer image of the optical image determined as a defect and the coordinates of the defect.

12. An inspection method, which irradiates light to a sample formed with a pattern, forming an image of the sample on an image sensor through an optical system, and determines the presence of a defect, characterized by comprising:

obtaining an optical image of the sample from the image sensor;

comparing the optical image with a reference image as a reference of the determination and, when a difference exceeds at least one of the threshold values, determining that there is a defect;

estimating a transfer image of the optical image and a transfer image of the reference image by simulation;

comparing the transfer image of the optical image and the transfer image of the reference image and when a difference exceeds at least one of the threshold values, determining that there is a defect;

reviewing the optical image, the reference image and each of the transfer images and determining necessity of repair to be applied to the defect.

13. The inspection method according to claim 12, characterized by further comprising:

obtaining an optical image, which is determined as a defect by comparing the optical image and the reference image, and simulating repair of the defect,

wherein in the step of estimating the transfer image, a transfer image of the simulated optical image and a transfer image of the reference image are estimated.

14. The inspection method according to claim 13, characterized by further comprising, comparing each transfer image of the optical image and the simulated optical image and estimating a portion to be repaired when it is determined that the defect is required to be repaired.

15. The inspection method according to claim 12, characterized in that the transfer image of the optical image is estimated based on an optical image including all defects in a predetermined range.

16. An inspection method characterized by comprising:

illuminating light to a sample formed with a pattern, forming an image of the sample on an image sensor through an optical system, obtaining an optical image of the sample from the image sensor, and comparing the obtained optical image with a reference image and when a difference exceeds at least one of the threshold values, determining that there is a defect;

reviewing the optical image including the defect and the reference image corresponding to the optical image and determining necessity of repair applied to the defect;

determining whether or not each transfer image of the optical image and the reference image is required to be estimated;

when each of the transfer images is required to be estimated, estimating and comparing each of the transfer images, when a difference exceeds at least one of the threshold values, determining that there is a defect, reviewing each of the transfer images, and determining the necessity of the repair applied to the defect;

when each of the transfer images is not required to be estimated, reviewing an optical image including another defect and a reference image corresponding to the optical image, and determining the necessity of the repair applied to another defect.

17. The inspection method according to claim 16, characterized by further comprising:

comparing the optical image with the reference image, obtaining the optical image determined as a defect, and simulating repair to the defect,

wherein, when each of the transfer images is required to be estimated, a transfer image of the simulated optical image is estimated.