Throttling Element Particle Detector for Semiconductor Wafer Monitoring
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Solution Overview
Problem
In situ particle detection in semiconductor manufacturing is hindered by poor correlation with wafer surface contamination, limited detection volume, optical and electrical noise, and lack of suitable ports for sensor installation, leading to inefficient monitoring and increased downtime.
Innovation Solution
A particle detector system incorporating a throttling element with an aerodynamic aperture, where a low-divergence light source illuminates the aperture, and a detector receives scattered light from particles traversing the aperture, optimizing particle detection efficiency and compatibility with existing semiconductor tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ISPM sensors are installed in pump-line configuration, then continuous monitoring is provided, but detection volume is limited and correlation with wafer surface contamination is poor
Solution Approach 1:
The patent transitions from pump-line installation to a configuration where the sensor is positioned close to the wafer processing location. This spatial repositioning changes the detection geometry, allowing the sensor to monitor particles in the vicinity of the wafer surface where contamination actually occurs, thereby improving both detection volume relevance and correlation with actual contamination.
2Reliability
If physical maintenance is performed frequently, then particle contamination is reduced, but downtime increases and productivity decreases
Solution Approach 1:
The patent implements real-time particle monitoring that provides continuous feedback on contamination levels. This feedback mechanism allows the system to detect particle accumulation trends and trigger maintenance only when necessary, replacing fixed-schedule maintenance with condition-based maintenance. Consequently, wafer yield is maintained through timely detection while unnecessary downtime is eliminated.
3Reliability
If chamber clean is performed frequently, then particle contamination is eliminated, but process time increases and manufacturing efficiency decreases
Solution Approach 1:
The patent enables early detection of particle formation through continuous monitoring, allowing preventive action to be taken before extensive particle contamination occurs. By detecting particles in their early stages, the system can trigger targeted cleaning or process adjustments before a full chamber clean is necessary, thereby maintaining wafer yield while minimizing time loss.
4Measurement precision
If ex situ metrology is used between process steps, then particle detection is provided, but detection is not continuous and particles may be moved during handling
Solution Approach 1:
The patent replaces mechanical particle handling and transfer operations with an in-situ optical detection system. By using light scattering detection, the system measures particles without physical contact or mechanical manipulation, eliminating the risk of particle movement during handling while providing continuous automated monitoring throughout the process.
5Reliability
If sensor ports are added to existing tools, then in-situ detection is enabled, but device complexity increases and retrofit difficulty increases
Solution Approach 1:
The patent designs the sensor system to utilize existing structural elements and access points in the tool, making the detection apparatus multi-functional with existing components. By adapting to rather than adding to the existing tool architecture, the system enables in-situ monitoring while minimizing increases in device complexity and retrofit difficulty.
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
The solution enhances particle detection efficiency, reduces downtime, and improves correlation with wafer surface contamination, enabling real-time monitoring and maintaining desirable manufacturing yields by matching the light source with the aerodynamic aperture and using a throttling element to focus and shape the light beam effectively.
Implementation Method 1
A detector is configured to receive a light scattered from one or more particles which traverse the aerodynamic aperture
Data Source
AI summary
A particle detector includes at least one throttling element which defines an aerodynamic aperture. A light source illuminates a region of the aerodynamic aperture at about a focal point of an aerodynamic lens. A detector is configured to receive a light scattered from one or more particles which traverse the aerodynamic aperture. A method for detecting and measuring particles previously deposited on a surface of a semiconductor manufacturing chamber is also described.