Semiconductor Defect Detection via Shadow Length Measurement
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Solution Overview
Problem
As integration of semiconductor devices increases, defects become significant operational issues, affecting the yield of semiconductor devices, and existing methods, such as electron microscopes, while effective, require improved defect detection and management techniques.
Innovation Solution
A defect detecting device and method that utilizes a scanning electron microscope (SEM) system, including a lamp with multiple light sources and a test device with memory and controller, to calculate the height of patterns on semiconductor samples by measuring shadow lengths and brightness, using reference data to determine defect patterns based on threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron microscopes are used to detect defects, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary measurement approach by using shadow length as a mediator parameter between the light source and pattern height. Instead of directly measuring pattern height with complex electron microscopy, the system uses shadow length measurement combined with reference data to calculate height, simplifying the detection system while maintaining precision.
Solution Approach 2:
The patent replaces complex mechanical/electronic measurement systems (electron microscopes) with a simpler optical measurement system based on shadow length measurement. The height calculation is performed through computational methods using reference data rather than direct physical measurement, reducing device complexity.
2Manufacturing precision
If pattern height is measured to detect defects, then manufacturing precision is improved, but measurement precision requirements increase
Solution Approach 1:
The patent applies preliminary action by creating reference data in advance that includes shadow length measurements and corresponding pattern heights for standard patterns. This pre-established reference data allows for simplified measurement during actual defect detection, as the system only needs to measure shadow lengths and compare against pre-calculated values rather than requiring high-precision direct height measurement.
Solution Approach 2:
The patent uses copying by creating a reference database that copies the relationship between shadow lengths and pattern heights for various standard patterns. During defect detection, the system measures shadow lengths and matches them against the copied reference data to determine pattern heights, reducing the precision requirements for actual measurement operations.
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 detection and management of defects on semiconductor wafers, enhancing the yield and quality of semiconductor devices by accurately identifying and correcting pattern defects.
Implementation Method 1
a lamp including a plurality of light sources and irradiating light onto a semiconductor sample
Implementation Method 2
a scanning electron microscope (SEM) device configured to generate an image, the image including a pattern formed on the semiconductor sample by the light and a second shadow of the pattern formed on the semiconductor sample by the light
Data Source
AI summary
A test device includes a memory and a controller. The memory stores reference data including a reference image obtained by photographing a reference pattern on a first semiconductor sample, a first height of the reference pattern, a first shadow length of the reference pattern, and a reference value that represents a correlation between the first height and the first shadow length. The controller receives an image obtained by photographing a pattern on a second semiconductor sample, measures a second shadow length of the pattern from the image, and calculates a second height of the pattern from the second shadow length based on the reference data.