Defect estimation device and method and inspection system and method

• US 8,737,676 B2
• Filed: 01/31/2011
• Issued: 05/27/2014
• 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): Rahmjoo, Mike
• Application Number:
  US13/017,641
• Publication Number:
  US 20110188734A1
• Time in Patent Office: 1,212 Days
• Field of Search: 382/100, 382/149, 382/144, 382/145, 382/154, 382/248, 382/283, 356/237.5, 356/237.4
• US Class Current: 382/100
• 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 acquiring part which obtains a reference image and an optical image of a pattern formed on a mask;

a simulator which utilizes the images obtained in the acquiring part, and estimates first images of the patterns obtained by transferring their images onto a substrate by a lithography process;

a comparing unit which compares the first images with each other and when a difference exceeds at least one of threshold values, determines that there is a defect in the optical image of the pattern formed on the mask;

a simulation repair circuit which simulates a repair to the optical image at a portion determined as defective by the comparing unit and, utilizing the reference image and the image obtained in the simulation repair circuit, estimates second images of the patterns obtained by transferring the images onto a substrate by the lithography process; and

wherein, the second images are compared with each other to confirm whether the defect is eliminated by simulation repair.

2. 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 acquiring part which obtains an optical image of a pattern formed on the mask from the image sensor and a reference optical image of the pattern formed on the mask;

a simulator which utilizes the images obtained in the acquiring part, and estimates first images of the patterns obtained by transferring the images onto a substrate by a lithography process;

a comparing unit which compares the first images with each other and when a difference exceeds at least one of threshold values, determines that there is a defect in the optical image of the pattern formed on the mask;

a simulation repair circuit which simulates a repair to the optical image at a portion determined as defective by the comparing unit and, utilizing the reference image and the image obtained in the simulation repair circuit, estimates second images of the patterns obtained by transferring the images onto a substrate by the lithography process; and

wherein the second images are compared with each other to confirm whether the defect is eliminated by the simulation repair.