Defect estimation device and method and inspection system and method

• US 8,781,212 B2
• Filed: 12/05/2012
• Issued: 07/15/2014
• Est. Priority Date: 02/01/2010
• Status: Expired due to Fees

• 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:
  US13/705,618
• Publication Number:
  US 20130094752A1
• Time in Patent Office: 587 Days
• Field of Search: 382/149, 382/145, 382/144, 382/154, 382/248, 382/283
• 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:

a first acquiring part which obtains a reference image and an optical image of a pattern formed on a mask;

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

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

a simulation repair part which simulates a repair to the optical image of the pattern at a portion determined as defective by the first comparison part;

a second estimation part which utilizes the reference image and the image obtained in the simulation repair part, and estimates second images of second transfer patterns obtained by transferring the images onto a substrate by a second lithography process,

wherein the second lithography process is the same or more advanced than the first lithography process; and

a second comparison part which compares the second images with each other and confirms whether or not the defect is eliminated by the simulation repair.

2. A defect estimation method for estimating a defect on a mask used in a defect estimation device, the defect estimation method comprising:

obtaining an optical image of a pattern formed on a mask and a reference image of said pattern using an optical image acquisition part;

simulating first pattern images respectively corresponding to transferring the optical and reference images of the pattern to a substrate using a simulation part;

comparing the first pattern image simulated from the optical image and the first pattern image simulated from the reference image with each other using a first comparison part;

detecting defects in the first pattern image simulated from the optical image when a difference exceeds at least one of a plurality of threshold values;

simulating repair of the optical image of the pattern at a portion determined as defective by the defect detection using a simulation repair part;

simulating second pattern images respectively from a repaired optical image and the reference image;

comparing the second pattern images and the reference image with each other using a second comparison part; and

making confirmation whether or not the defect is eliminated.

3. 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:

a first acquiring part which obtains a reference image and an optical image of a pattern formed on a mask;

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

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

a simulation repair part which simulates a repair to the optical image of the pattern at a portion determined as defective by the first comparison part; and

a second estimation part which utilizes the reference image and the image obtained in the simulation repair part, and estimates second images of second transfer patterns obtained by transferring the reference image and the image obtained in the simulation repair part onto a substrate by a second lithography process, wherein the second lithography process is the same as or more advanced than the first lithographic process; and

a second comparison part which compares the second images with each other and confirms whether or not the defect is eliminated by the simulation repair.