Imaging Ellipsometry Inspection for Wafer Precision and Throughput
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Solution Overview
Problem
Current inspection technologies face challenges in achieving precise, high-speed, and large-area measurements of measurement keys on wafers, leading to reduced measurement consistency and throughput due to limitations in spot size and resolution.
Innovation Solution
The implementation of an imaging ellipsometry-based inspection method using a dual-mode inspection device with a high-resolution vertical optical system and a large-area tilted optical system, allowing for simultaneous measurement of patterns across multiple cells within the field of view, and the extraction of intensity data at various wavelengths to determine wafer normalcy and facilitate semiconductor processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional inspection device with limited spot size is used, then measurement precision is improved, but productivity deteriorates due to reduced measurement area and speed
Solution Approach 1:
The inspection device is divided into two distinct optical systems: a vertical optical system for high-precision measurement of individual measurement keys, and a tilted optical system for large-area simultaneous measurement of multiple measurement keys. This segmentation allows each system to be optimized for its specific function, resolving the contradiction between precision and productivity.
Solution Approach 2:
The patent introduces a tilted optical system that operates at an angle relative to the wafer surface, providing a different measurement dimension compared to the conventional vertical system. This dimensional change enables simultaneous measurement of multiple measurement keys across a large area while maintaining measurement capability, thereby improving productivity without sacrificing precision.
2Device complexity
If a single optical system is used, then device complexity is reduced, but measurement consistency deteriorates due to inability to maintain precision across large areas
Solution Approach 1:
The inspection device is divided into two distinct optical systems: a vertical optical system for high-precision measurement of individual measurement keys, and a tilted optical system for large-area simultaneous measurement of multiple measurement keys. This segmentation allows each system to be optimized for its specific function, resolving the contradiction between precision and productivity.
Solution Approach 2:
The patent combines two different optical systems (vertical and tilted) into a single integrated inspection device that can switch between or simultaneously use both systems. This merging allows the device to maintain high measurement consistency across the entire wafer surface by selecting the appropriate system based on the measurement requirements, thereby improving reliability without excessive complexity.
3Productivity
If measurement area is increased, then productivity is improved, but measurement precision deteriorates due to signal distortion and noise
Solution Approach 1:
The inspection device is divided into two distinct optical systems: a vertical optical system for high-precision measurement of individual measurement keys, and a tilted optical system for large-area simultaneous measurement of multiple measurement keys. This segmentation allows each system to be optimized for its specific function, resolving the contradiction between precision and productivity.
Solution Approach 2:
The patent applies different measurement approaches to different regions: the vertical optical system provides high-precision local measurement for individual measurement keys, while the tilted optical system provides broader coverage for multiple keys. This local quality differentiation ensures that precision is maintained where needed while achieving large-area productivity.
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, high-speed, and large-area measurement of measurement keys, improving measurement consistency and throughput while reducing signal distortion and noise, thereby enhancing the accuracy of semiconductor process control.
Implementation Method 1
Ellipsometry is an optical technique for studying dielectric properties of wafers. Ellipsometry allows the calculation of information about specimens by analyzing polarization changes of reflected light that is reflected by the specimens
Implementation Method 2
imaging ellipsometry (IE) and spectroscopic imaging ellipsometry (SIE) are types of ellipsometry using a broadband light source
Data Source
AI summary
Provided is an imaging ellipsometry (IE)-based inspection method including selecting a mode from among a first mode of an IE-based inspection device having a first field of view (FOV) and a second mode of an IE-based inspection device having a second FOV, measuring an inspection target by the IE-based inspection device based on the selected mode, and determining whether the inspection target is normal based on a result of the measuring, wherein the measuring of the inspection target comprises simultaneously measuring patterns included in a plurality of cells provided in a region of the inspection target, the region corresponding to an FOV of the selected mode.