Optical Microscope for Semiconductor Defect Position Correction
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Solution Overview
Problem
Current defect review methods in semiconductor manufacturing face challenges with low throughput due to large error components in defect position detection, leading to inefficient SEM analysis and increased apparatus size and cost.
Innovation Solution
A method and apparatus that utilize an optical microscope to correct defect position information, allowing defects to be precisely brought into the viewing field of an electron microscope, enhancing throughput and reducing apparatus size by adjusting focus and position using a movable stage and optical systems with light-field and dark-field illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam of large spot size is used to scan the semiconductor substrate for defect detection, then the throughput of inspection is increased, but the precision of the detect position includes large error components
Solution Approach 1:
The patent introduces an optical microscope as an intermediary device between the optical particle inspection system and the SEM. The optical microscope captures images of defects with higher position precision and provides corrected position information to the SEM, mediating the transition from low-precision detection to high-precision review without sacrificing throughput.
Solution Approach 2:
The patent replaces the mechanical scanning method with large spot size laser beam with an optical imaging approach using an optical microscope. Instead of mechanically scanning and calculating positions, the system uses optical imaging to directly capture defect positions with higher precision, substituting mechanical measurement with optical measurement.
2Manufacturing precision
If the viewing field of the SEM is moved to search for the defect while using higher magnification, then the defect can be reviewed in detail, but it takes much time and the throughput of the SEM reviewing declines
Solution Approach 1:
The patent performs preliminary action by having the optical microscope capture defect images and calculate precise position information before the SEM review. This preliminary positioning ensures that when the SEM views the defect, the viewing field is already correctly positioned, eliminating the need for time-consuming searching and focusing during the actual SEM review process.
Solution Approach 2:
The patent implements feedback by using the optical microscope to detect defect positions and provide corrected position information back to the SEM. The SEM receives feedback about the exact location of defects from the optical microscope, allowing it to directly position the viewing field without trial-and-error searching, thus maintaining high throughput while achieving detailed review.
3Measurement precision
If a stage is employed to move up and down the semiconductor substrate for focusing the optical microscope, then the focus can be adjusted, but the apparatus becomes expensive and massive
Solution Approach 1:
The patent extracts the focusing function from the mechanical stage and assigns it to the optical microscope system itself. By removing the requirement for vertical stage movement, the system eliminates the need for complex mechanical focusing mechanisms, reducing apparatus size and cost while maintaining focus adjustment capability through the optical system's own focusing mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise defect review by SEM, increasing throughput and making the apparatus more compact and cost-effective by correcting defect position information and focusing mechanisms.
Implementation Method 1
an optical visual inspection system or a SEM inspection system with a lamp light or a laser beam or an electron ray as its illumination light, which detects a light-field optical image of a semiconductor substrate
Implementation Method 2
an optical particle inspection system that implements dark-field illumination on the surface of a semiconductor substrate by a laser beam, detects scattering light from a defect
Implementation Method 3
reviewing is made by use of a SEM (Scanning Electron Microscope)
Data Source
AI summary
A method of inspecting defects of a sample on a movable table includes a first step for, on a basis of position information of the defects which is previously detected by an other inspection system, driving the table so that the defects come into a viewing field of an optical microscope having a focus which is adjusted, a second step for re-detecting the defects to obtain a first detection result, a third step for correcting the position information of defects on a basis of position information of the re-detected defects, and a fourth step for reviewing the defects whose position information is corrected to obtain a second detection result. At the second step, re-detecting is performed using reflection light or scattered light from the sample which passes an optical filter which includes a light shielding portion and a light transmitting portion.