Second Harmonic Generation Defect Detection on Semiconductor Substrates
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Solution Overview
Problem
Highly integrated semiconductor devices are prone to errors due to smaller defect sizes that conventional detection methods cannot accurately or rapidly identify, necessitating a method for detecting nano-sized defects on substrates.
Innovation Solution
A method and apparatus utilizing a second harmonic generation (SHG) beam to detect defects on substrates, where an incident light beam is radiated to generate reflected beams, and the SHG beam, specifically generated by defects, is isolated and detected using a filter and detector system, allowing for accurate and rapid identification of nano-sized defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods are used, then the detection process is simple, but nano-sized defects cannot be accurately detected
Solution Approach 1:
The patent extracts the SHG beam signal from the complex reflected light by using a dichroic mirror that selectively transmits only the SHG frequency component (2ω) while blocking the fundamental frequency (ω) and other components. This extraction enables precise detection of nano-sized defects through the unique SHG signal generated only by defective regions, resolving the contradiction between detection accuracy and system complexity.
Solution Approach 2:
The patent changes the frequency parameter of the detected signal from the fundamental frequency ω to the second harmonic frequency 2ω. By detecting the SHG beam at a different frequency band than the incident light, the system achieves high precision detection of nano-defects while maintaining manageable system complexity through frequency-based separation.
2Productivity
If conventional detection methods are used, then the equipment is simple, but detection speed is insufficient for mass production
Solution Approach 1:
The patent enables continuous defect detection by maintaining a steady SHG signal generation process. The SHG beam is continuously generated by the incident laser beam interacting with the substrate, and the detection system continuously monitors the SHG signal. This continuous action allows for rapid scanning and detection of nano-sized defects across the entire substrate surface, achieving both high productivity and precision.
Solution Approach 2:
The patent replaces conventional mechanical or optical detection systems with a frequency-selective optical detection system based on SHG. By substituting the detection mechanism with a frequency-based optical filtering approach (using dichroic mirrors and bandpass filters), the system achieves both rapid detection speed suitable for mass production and the precision required for nano-sized defect identification.
3Measurement precision
If all reflected beams are detected, then the detection process is simple, but signal interference from substrate surface reduces detection accuracy
Solution Approach 1:
The patent segments the reflected light into different frequency components using a dichroic mirror. The SHG beam at frequency 2ω is separated from the fundamental frequency ω and other reflected components. This segmentation allows the detection system to focus exclusively on the SHG signal generated by defects, eliminating interference from the substrate surface and other non-defect regions, thereby achieving high measurement precision.
Solution Approach 2:
The patent introduces frequency-selective optical elements (dichroic mirror and bandpass filter) as intermediaries between the reflected light and the detector. These intermediaries selectively transmit the SHG frequency component while blocking other frequencies, acting as a mediator that isolates the defect signal from interfering substrate surface reflections, thus improving detection accuracy without requiring complex signal processing.
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 precise and swift detection of nano-sized defects on substrates, enhancing the manufacturing of semiconductor devices by identifying defects that could cause errors in highly integrated circuits.
Implementation Method 1
A second harmonic generation (SHG) beam among the reflected light beams may be detected. The SHG beam may be generated by a defect on the substrate.
Data Source
AI summary
In a method of detecting a defect on a substrate, an incident beam may be radiated to a surface of the substrate to generate reflected light beams. A second harmonic generation (SHG) beam among the reflected light beams may be detected. The SHG beam may be generated by a defect on the substrate. A nano size defect may be detected by examining the SHG beam.