Wafer Alignment Photosensors for High-Speed Handling Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed wafer handling in semiconductor manufacturing leads to deviations, causing uniformity issues and potential damage, and existing solutions like digital sampling and encoder pulse counting are costly and inefficient.
Innovation Solution
A semiconductor manufacturing apparatus with photosensors positioned forward and on the side of the wafer handling device, using a peak hold circuit to detect and correct deviations without reducing handling speed or increasing data sampling frequency, eliminating the need for a dedicated built-in detection part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital sampling at 100ms frequency is used to detect wafer deviation, then the system can detect wafer position errors, but the sampling rate is too slow to track high-speed arm operation
Solution Approach 1:
The patent replaces the mechanical encoder pulse counting system with an optical sensing system using photosensors. The photosensors optically detect wafer position by measuring light blockage, eliminating the need for high-speed mechanical encoders and enabling accurate position detection at high speeds without mechanical limitations
Solution Approach 2:
The patent introduces photosensors as an intermediary detection mechanism between the wafer and the control system. Instead of directly measuring encoder pulses or mechanical position, the system uses light interaction (blockage detection) as an intermediary to infer wafer position, enabling indirect but accurate high-speed position measurement
2Measurement precision
If sampling frequency is increased to track high-speed arm operation, then detection accuracy improves, but data storage requirements and system cost increase
Solution Approach 1:
The patent extracts only the essential position information needed for correction by using photosensors to detect wafer position at critical points. Instead of continuously sampling and storing all motion data at high frequency, the system extracts position data only when needed for deviation detection and correction, minimizing data storage requirements while maintaining accuracy
Solution Approach 2:
The patent performs preliminary position detection using photosensors before the wafer is fully loaded, allowing the system to detect and correct deviations in advance. This preliminary detection approach eliminates the need for continuous high-speed sampling during the entire operation, reducing overall data processing and storage requirements
3Measurement precision
If a dedicated built-in wafer deviation detection part is added to the handling device controller, then deviation detection accuracy improves, but system cost increases
Solution Approach 1:
The patent makes the photosensor system multi-functional by using it for both primary position detection and deviation detection. The same photosensors that track wafer position during loading also detect deviations, eliminating the need for separate dedicated detection hardware and reducing overall system complexity and cost
Solution Approach 2:
The patent merges the deviation detection function with the existing position detection system. Instead of adding a separate built-in deviation detection part, the system combines deviation detection capabilities into the photosensor-based position monitoring system, reducing controller complexity while maintaining detection accuracy
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 accurate and cost-effective detection and correction of wafer deviations, maintaining high throughput without the need for high-speed sampling or additional hardware, effectively addressing the challenges of high-speed wafer handling.
Implementation Method 1
photosensors positioned forward of and on a side of the wafer placed on the wafer handling device, where the output signal from the forward photosensor is detected while the wafer handling device is stationary, and the output signal from the side photosensor is detected at the time the wafer passes the sensor
Data Source
AI summary
A semiconductor-processing apparatus includes: a wafer handling chamber; a wafer processing chamber; a wafer handling device; a first photosensor disposed in the wafer handling chamber in front of the wafer processing chamber at a position where the wafer partially blocks light received by the first photosensor at a ready-to-load position and substantially entirely blocks light received by the first photosensor when the wafer moves from the ready-to-load position toward the wafer processing chamber in the x-axis direction; and a second photosensor disposed in the wafer handling chamber in front of the wafer processing chamber at a position where the wafer does not block light received by the second photosensor at the ready-to-load position and partially blocks light received by the second photosensor when the wafer moves from the ready-to-load position toward the wafer processing chamber in the x-axis direction.