Substrate Inspection Laser Beam Splitter and Feedback Modulator
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Solution Overview
Problem
As semiconductor devices become highly integrated, internal defects can significantly affect their reliability and performance, necessitating advanced techniques for inspecting internal structures.
Innovation Solution
A substrate inspection apparatus that modulates laser beams in time and space, using a laser light source, optical splitter, delay stage, modulator, and feedback system to change the intensity, wavefront, and frequency of laser beams for detailed inspection of substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser inspection methods are used, then the inspection process is simple, but the inspection detail and internal structure detection capability are insufficient
Solution Approach 1:
The laser beam is divided into multiple sub-beams using a beam splitter, with each sub-beam directed to different inspection regions or depths within the substrate. This segmentation enables detailed inspection of internal structures by examining different layers simultaneously with specialized laser parameters.
Solution Approach 2:
The patent implements dynamic control of laser parameters including real-time adjustment of laser intensity, pulse width, and frequency modulation. The delay stage dynamically adjusts the time delay between laser pulses to optimize interaction with different substrate layers, enabling adaptive inspection of complex internal structures.
2Measurement precision
If laser intensity is increased to detect deeper internal defects, then detection capability improves, but damage to the substrate increases
Solution Approach 1:
The system uses periodic pulse laser illumination with variable pulse widths and intervals. By controlling the pulse duration and repetition rate, the system delivers sufficient energy for deep defect detection while allowing heat dissipation between pulses, preventing thermal damage to the substrate.
Solution Approach 2:
The patent dynamically adjusts multiple laser parameters including intensity, frequency, pulse width, and wavelength based on the inspection depth and substrate properties. This multi-parameter optimization enables deep penetration for defect detection while maintaining safe energy levels to avoid substrate damage.
3Adaptability or versatility
If multiple laser beams are used to inspect different layers, then inspection comprehensiveness improves, but system complexity increases
Solution Approach 1:
A single laser source generates multiple laser beams with different parameters (intensity, frequency, pulse width) that can inspect various substrate layers. The beam splitter and delay stage configuration allows one laser system to perform multiple inspection functions across different depths and regions, eliminating the need for separate laser systems for each layer.
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 detailed inspection of internal structures and desired layers within substrates, improving the detection of defects and enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
a laser light source configured to emit a laser beam
Implementation Method 2
an optical splitter configured to split the laser beam into a first laser beam and a second laser beam
Implementation Method 3
a modulator optically connected to the optical splitter and configured to change the first laser beam
Implementation Method 4
a feedback system configured to sense the second laser beam reflected from a substrate and configured to apply electrical feedback to the first modulator
Data Source
AI summary
A substrate inspection apparatus includes a laser light source configured to emit a laser beam, an optical splitter configured to split the laser beam into a first laser beam and a second laser beam, a delay stage configured to change a relative time delay of the second laser beam and optically connected to the optical splitter, a first modulator optically connected to the optical splitter and configured to change the first laser beam, and a feedback system configured to sense the second laser beam reflected from a substrate and configured to apply electrical feedback to the first modulator.