Dynamic Lot Measurement Using Equipment Reliability Index
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Solution Overview
Problem
In semiconductor manufacturing, existing measurement methods are not optimally controlled for quality monitoring, as they do not consider equipment reliability, and manual measurements are often performed only under specific circumstances, leading to suboptimal quality control.
Innovation Solution
A method and system for dynamically controlling lot measurement based on a risk score calculated using an equipment reliability index, which combines process stability and equipment stability to determine whether to measure semiconductor products, with the risk score adjusted in real-time according to the number of products processed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If measurement is performed at fixed periods, then measurement schedule is simple and easy to manage, but quality monitoring is not optimal and does not consider equipment reliability
Solution Approach 1:
The patent implements dynamic measurement scheduling by calculating equipment reliability indices in real-time and adjusting measurement frequency based on current equipment state. The system transitions from static fixed-period measurement to dynamic measurement intervals that adapt to equipment reliability changes, ensuring optimal quality monitoring while maintaining manageable complexity through automated calculations.
Solution Approach 2:
The system continuously monitors equipment parameters, calculates reliability indices, and uses this feedback to adjust measurement schedules. The feedback loop includes collecting process data, computing equipment reliability indices, determining risk scores, and automatically adjusting measurement frequency, creating a closed-loop system that improves quality monitoring effectiveness while maintaining operational simplicity.
2Reliability
If manual measurement is performed by engineers, then measurement can be performed under special circumstances, but measurement is performed only under limited conditions and not continuously optimized
Solution Approach 1:
The system enables self-service measurement control by automatically calculating equipment reliability indices, determining risk scores, and deciding measurement timing without engineer intervention. The automated system monitors equipment state continuously and triggers measurements based on calculated risk thresholds, eliminating the need for manual engineer judgment while maintaining flexible response to special circumstances.
Solution Approach 2:
The system changes the parameter of measurement frequency from fixed to variable based on equipment reliability indices. By calculating real-time reliability parameters and adjusting measurement intervals accordingly, the system achieves both flexible quality control for special circumstances and continuous optimization for normal operations, significantly improving measurement efficiency.
3Reliability
If all products are measured throughout the measurement period, then quality monitoring is comprehensive, but measurement resources are wasted on products with low risk
Solution Approach 1:
The patent applies local quality by differentiating measurement frequency based on specific equipment and process risk levels. Instead of uniform measurement of all products, the system calculates equipment-specific reliability indices and applies differential measurement strategies - high-risk equipment receives frequent measurement while low-risk equipment receives intermittent measurement, optimizing resource allocation while maintaining comprehensive quality monitoring coverage.
Solution Approach 2:
The system implements partial measurement action by measuring only the portion of products that require monitoring based on risk assessment. By calculating equipment reliability indices and risk scores, the system determines the minimum necessary measurement frequency for each equipment, avoiding excessive measurement of low-risk products while ensuring adequate monitoring of high-risk equipment, thus reducing measurement resource consumption.
4Reliability
If measurement frequency is increased to improve quality monitoring, then quality and yield improve, but measurement time and operational complexity increase
Solution Approach 1:
The system dynamically adjusts measurement frequency based on real-time equipment reliability indices rather than using fixed high-frequency schedules. By calculating equipment-specific risk scores and adapting measurement intervals accordingly, the system achieves high quality and yield monitoring for critical equipment while reducing unnecessary measurements for stable equipment, thereby optimizing measurement time utilization.
Solution Approach 2:
The feedback mechanism continuously monitors equipment state and adjusts measurement frequency to maintain optimal quality monitoring. The system calculates reliability indices, determines risk scores, and automatically adjusts measurement timing - increasing frequency when risk is high and decreasing when risk is low - thus achieving high quality monitoring efficiency without excessive measurement time consumption.
Data Source
AI summary
A method and a system for controlling a lot risk score based dynamic lot measurement on the basis of equipment reliability index are provided. The method for controlling a measurement, according to an embodiment of the present invention, calculates an equipment reliability index of specific equipment for a specific process in semiconductor manufacturing, calculates a risk score of the specific equipment for the specific process on the basis of an equipment reliability index, and determines, on the basis of the risk score, whether to measure a semiconductor product processed by the specific equipment for the specific process. Therefore, differential quality monitoring and management is possible according to the equipment reliability index, a measuring instrument can be efficiently used, quality and yield can be improved through timely measurement, and management convenience can be increased through automatic and dynamic lot measurement control.