Defect estimation device and method and inspection system and method

• US 9,177,372 B2
• Filed: 01/21/2015
• Issued: 11/03/2015
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Original Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Inventors: Tsuchiya, Hideo, Abe, Takayuki
• Primary Examiner(s): GORADIA, SHEFALI DINESH
• Application Number:
  US14/601,846
• Publication Number:
  US 20150131892A1
• Time in Patent Office: 286 Days
• Field of Search: 382/144, 382/149, 382/154, 382/248, 382/283
• US Class Current: 1/1
• 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. 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, comparing the obtained optical image with a reference image and, when a difference exceeds at least one of a plurality of 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; and

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 including another defect, and determining the necessity of the repair applied to the another defect.

2. The inspection method according to claim 1, characterized by further comprising:

comparing the optical image with the reference image, obtaining 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.

3. A defect estimation device comprising:

an estimation part configured to utilize a reference image of a mask pattern and a corresponding optical image, and obtain an estimated reference pattern image and a first candidate pattern image of the mask pattern transferred to a substrate by a lithography process; and

a simulation repair part configured to simulate a repair to the optical image based on the reference pattern image and the first candidate pattern image,

wherein second candidate pattern images of the mask pattern transferred to the substrate by the lithography process are estimated using a simulation repair image of the optical image to which the repair is simulated by the simulation repair part, and

the reference pattern image and each of the second candidate pattern images are compared with each other to confirm whether a defect is eliminated.

4. A defect estimation device comprising:

a first estimation part configured to utilize a reference image of a mask pattern and a corresponding optical image, and estimate a first reference pattern image and a first candidate pattern image of the mask pattern transferred to a substrate by a first lithography process;

a simulation repair part configured to simulate a repair to the optical image based on the reference pattern image and the first candidate pattern image; and

a second estimation part configured to utilize the reference image and a simulation repair image of the optical image to which the repair is simulated by the simulation repair part, and estimate a second reference pattern image and a second candidate pattern image of the mask pattern transferred to the substrate by a second lithography process which is the same as or more advanced than the first lithography process,

wherein the second reference pattern image and the second candidate pattern image are compared with each other to confirm whether a defect is eliminated.