Substrate Processing Apparatus Adaptive Detection Thresholds
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in efficiently detecting substrate abnormalities, such as cracks, and in effectively reusing dummy wafers due to fixed allowed values that do not account for different substrate types, leading to reduced operation rates and premature dummy wafer replacement.
Innovation Solution
A configuration that includes a substrate retaining mechanism, a detecting unit, a first determination unit for comparing detection data with master data, a confirmation unit to identify substrate type, and a second determination unit to adjust allowed values based on substrate type, allowing for differential abnormality detection and extended reuse of dummy substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed allowed value is used for substrate abnormality detection, then the detection criterion is simple and consistent, but the operation rate decreases and dummy substrate replacement cycle shortens due to premature detection of acceptable deformations
Solution Approach 1:
The patent applies dynamics by making the allowed value adjustable rather than fixed. The control unit dynamically changes the allowed value based on substrate type identification, enabling the system to adapt detection criteria to different substrate characteristics and usage scenarios
Solution Approach 2:
The patent changes the parameter of allowed value based on substrate type. By identifying whether the substrate is a product substrate or dummy substrate and adjusting the allowed value accordingly, the system optimizes detection sensitivity for each case, preventing premature rejection of acceptable dummy substrates while maintaining strict control for product substrates
2Reliability
If a ring-shaped retaining member is mounted on the boat, then process performance is improved, but the wafer crack detection mechanism cannot be used because the retaining member affects the optical waveform
Solution Approach 1:
The patent changes the detection parameter from optical waveform analysis to direct physical state detection. By using a detection unit that measures substrate placement state directly rather than through optical waveforms affected by the retaining member, the system enables crack detection while maintaining the retaining member for process performance
Solution Approach 2:
The patent replaces the optical detection system with a mechanical or electrical detection system. The detection unit directly senses substrate placement state without relying on optical waveforms that are disrupted by the ring-shaped retaining member, thus eliminating the interference problem
3Measurement precision
If strict determination of distortion is applied to product wafers, then detection precision is high, but dummy wafers must be replaced frequently even with minor distortion, reducing operation rate
Solution Approach 1:
The patent applies local quality by setting different allowed values for different substrate types. Product substrates receive strict determination with low allowed values for high precision, while dummy substrates receive lenient determination with high allowed values to accommodate normal deformation and extend usage life
Solution Approach 2:
The system dynamically adjusts the allowed value based on substrate type identification. The control unit switches between strict and lenient determination criteria, enabling high measurement precision for product substrates while maintaining high dummy wafer utilization through adaptive threshold adjustment
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 precise abnormality detection tailored to specific substrate types, improving operation rates and extending the usage and replacement cycles of dummy substrates, while preventing apparatus downtime and reducing costs.
Implementation Method 1
a photoelectric sensor arranged in a horizontal direction at a position at which a wafer end face is detected is moved at a constant speed in a vertical direction
Data Source
AI summary
A substrate processing apparatus includes a substrate retaining mechanism; a detecting unit detecting a placed state of the substrate retained by the substrate retaining mechanism; a first determination unit comparing detection data of the substrate obtained by the detecting unit with master data that is a reference to determine if the detection data is within a first allowed value; a confirmation unit confirming substrate type; a second determination unit comparing the detection data of the substrate with the master data to determine if the detection data is within a second allowed value; and a transfer control unit controlling the substrate retaining mechanism depending on a determination result of the second determination unit when substrate type is confirmed as a predetermined type by the confirmation unit when it is determined that the detection data is not within the first allowed value as determined by the first determination unit.