Wafer Foreign Matter Inspection Using Multi-Wavelength Laser Reflectance
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Solution Overview
Problem
Current methods for inspecting wafers to determine whether foreign matters are metal or non-metallic take a long time, hindering rapid identification and affecting the manufacturing efficiency of electronic components.
Innovation Solution
A method and device using a laser beam with three or more distinct wavelengths to irradiate the wafer surface, detecting reflected light, and determining the nature of foreign matters based on reflectance differences across these wavelengths, allowing for quick identification of metals or non-metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods are used to determine whether foreign matter is metal or non-metal, then measurement precision is achieved, but inspection time becomes excessively long
Solution Approach 1:
The patent changes the parameter of light wavelength by using multiple distinct wavelengths (first, second, and third wavelengths) to irradiate the wafer surface. By measuring reflectance at these different wavelengths and analyzing the variations, the system can rapidly determine whether foreign matter is metallic or non-metallic without requiring time-consuming conventional analysis methods.
Solution Approach 2:
The patent replaces conventional mechanical or chemical analysis methods with an optical measurement system. By using light reflection characteristics at different wavelengths, the system substitutes complex physical/chemical identification processes with a faster optical detection mechanism, achieving both speed and accuracy in foreign matter classification.
2Productivity
If rapid inspection is implemented to improve productivity, then inspection time is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent uses multiple wavelength parameters simultaneously to maintain measurement precision while improving speed. By acquiring reflectance data at three distinct wavelengths and analyzing the pattern of variations, the system achieves rapid foreign matter identification without sacrificing accuracy, as the multi-parameter approach provides sufficient information for reliable classification.
Solution Approach 2:
The patent applies partial action by measuring only the essential reflectance characteristics at selected wavelengths rather than performing complete spectral analysis. This selective measurement approach provides enough information for accurate foreign matter classification while significantly reducing inspection time compared to comprehensive analysis methods.
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
Enables rapid and precise determination of foreign matter type, reducing the likelihood of defective electronic component production by distinguishing between metallic and non-metallic foreign matters, thereby improving manufacturing efficiency.
Implementation Method 1
detecting a reflected light from the surface of the wafer when the surface of the wafer is irradiated with the laser beam
Data Source
AI summary
A method for inspecting a surface of a wafer, includes steps of: irradiating a surface of the wafer with a laser beam having three or more distinct wavelengths; detecting a reflected light from the surface of the wafer when the surface of the wafer is irradiated with the laser beam; and determining whether a foreign matter exists on the surface of the wafer based on reflectances of the surface of the wafer with respect to the laser beam having the three or more distinct wavelengths, wherein the step of determining whether the foreign matter exists includes a step of determining whether the foreign matter is a metal or a non-metal.