Dark-Field Defect Inspection Apparatus Feedback Control
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Solution Overview
Problem
Existing dark-field defect inspecting apparatuses in semiconductor and magnetic head manufacturing lines face challenges in maintaining consistent apparatus state and sensitivity across multiple machines, leading to instability and reduced detection accuracy due to variations in environmental conditions and apparatus configurations.
Innovation Solution
The implementation of a method that includes an illumination optical system and a detection system with monitoring and feedback control mechanisms to adjust the illumination light and detection system parameters based on real-time measurements of intensity distribution, polarization state, and environmental factors such as temperature and atmospheric pressure, ensuring that detection results align with ideal values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple dark-field defect inspecting apparatuses are arranged in a manufacturing line, then productivity is improved through increased inspection capacity, but sensitivity differences among apparatuses increase leading to inconsistent detection quality
Solution Approach 1:
The patent implements a feedback mechanism where the state of the illumination optical system is monitored and used to adjust the detection system. Specifically, the state information (including intensity distribution and polarization state) of the illumination light is fed back to control the detection optical system, ensuring that detection sensitivity remains consistent across multiple apparatuses even when environmental conditions vary.
Solution Approach 2:
The patent monitors and adjusts key parameters of the illumination optical system including intensity distribution and polarization state. By detecting changes in these parameters and相应地 adjusting the detection system parameters, the apparatus maintains consistent detection sensitivity across multiple units in the manufacturing line.
2Productivity
If environmental conditions such as temperature and atmospheric pressure vary, then apparatus operation continues without interruption, but apparatus state stability deteriorates leading to reduced detection accuracy
Solution Approach 1:
The patent incorporates environmental condition monitoring as part of the feedback loop. When environmental parameters such as temperature or atmospheric pressure change, the system detects the resulting changes in illumination light state and adjusts the detection system accordingly, maintaining stability despite continuous operation under varying environmental conditions.
Solution Approach 2:
The system proactively compensates for environmental variations by continuously monitoring the illumination state and pre-adjusting the detection system before significant drift occurs. This preliminary anti-action prevents deterioration of detection accuracy rather than reacting after problems arise.
3Measurement precision
If manual calibration and adjustment of each apparatus is performed, then individual apparatus sensitivity can be optimized, but time consumption and operational complexity increase significantly
Solution Approach 1:
The patent implements self-service calibration where the apparatus automatically monitors its own illumination state and adjusts its detection system without external intervention. The system measures the intensity distribution and polarization state of its own illumination light and autonomously optimizes detection parameters, eliminating the need for manual calibration of each apparatus.
Solution Approach 2:
The automatic feedback control system continuously monitors illumination parameters and adjusts detection settings in real-time, replacing manual calibration processes. This automated feedback loop maintains optimal sensitivity without requiring operator intervention, significantly reducing calibration time and operational complexity.
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 stabilizes apparatus performance, reduces sensitivity differences between machines, and enhances defect detection accuracy by maintaining consistent apparatus state and sensitivity, thereby improving operational efficiency.
Implementation Method 1
A dark-field defect inspecting method according to a typical embodiment of the present invention obtains a signal of scattered light occurring due to illumination light illuminating a surface of an inspection subject
Implementation Method 2
detecting light input to the detection system by a second sensor
Data Source
AI summary
By including an illumination system and a detection system, an information collecting function of monitoring an environment, such as temperature and atmospheric pressure, and an apparatus state managing function having a feedback function of comparing the monitoring result and a design value, a theoretical calculation value or an ideal value derived from simulation results and calibrating an apparatus so that the monitoring result is brought close to the ideal value, a unit for keeping the apparatus state and apparatus sensitivity constant is provided. A control unit 800 is configured to include a recording unit 801, a comparing unit 802, a sensitivity predicting unit 803, and a feedback control unit 804. In the comparing unit 802, the monitoring result transmitted from the recording unit 801 and an ideal value stored in a database 805 are compared with each other. When a difference between the ideal value and the monitoring result exceeds a predetermined threshold, the feedback control unit 804 corrects the illumination system and the detection system.