Wafer Blade Vibration Sensing for Precise Chipping Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional processing apparatuses face challenges in accurately detecting chipping during wafer processing due to difficulties in real-time detection and insufficient accuracy in determining the position of the rotatable blade's contact point, primarily caused by variations in blade wear and positional relations between the wafer and the processing table.
Innovation Solution
A processing apparatus equipped with a first sensor and a second sensor, where the second sensor differs in detection method, installation position, or measurement frequency, is used to extract start and stop point information, enabling precise determination of the characteristic vibration position on the workpiece, with the second sensor typically being an AE sensor and the first sensor an acceleration sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sensor is used to detect vibrations during processing, then the detection system is simple, but the accuracy of position determination for chipping detection is insufficient
Solution Approach 1:
The vibration detection system is segmented into multiple sensors with different functions: a first sensor (acceleration sensor) mounted on the blade driving shaft for detecting characteristic vibrations during processing, and a second sensor (AE sensor) mounted on the table for detecting contact start/stop points. This segmentation allows each sensor to be optimized for its specific detection task, thereby improving overall position determination accuracy without requiring a single complex sensor system.
2Reliability
If cutting water is sprayed onto the wafer during processing, then cooling and lubrication are provided, but real-time detection of chipping becomes difficult
Solution Approach 1:
The patent replaces optical detection methods (which are blocked by cutting water) with vibration-based acoustic emission detection. The AE sensor detects high-frequency elastic waves generated by chipping events, allowing real-time detection that penetrates through the cutting water medium. This substitution of detection mechanism eliminates the interference problem caused by cutting water spray.
3Measurement precision
If conventional vibration detection is used, then chipping can be detected, but the position of the rotatable blade contact point cannot be precisely determined due to blade wear and positional variations
Solution Approach 1:
The patent introduces the table-mounted AE sensor as an intermediary reference point that is independent of blade wear and wafer positioning variations. By detecting contact start/stop points at the table level rather than at the blade-wafer interface, the system obtains a stable reference frame for determining contact positions, eliminating the influence of blade wear and positional variations.
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 allows for accurate detection and removal of chipping defects, enhancing production efficiency and nondefective rates by precisely determining the position of processing defects on the workpiece.
Implementation Method 1
a first sensor for detecting a vibration generated by driving the rotatable blade
Implementation Method 2
a second sensor for detecting a vibration generated by driving the rotatable blade, the second sensor being different from the first sensor in at least one of detection method, installation position, and measurement frequency
Data Source
AI summary
A processing apparatus includes a rotatable blade, a blade driving shaft, a table, a position driving mechanism, a first sensor, a second sensor, a start/stop point information extraction section, a characteristic-vibration-information extraction section, and a characteristic-vibration-information extraction section. The shaft drives the blade. The table places a workpiece to be processed. The mechanism changes a relative position between the blade and the workpiece. The first sensor detects a vibration generated by driving the blade. The second sensor detects a vibration generated by driving the blade. The start/stop point information extraction section extracts at least one of a start point information regarding a contact start point and a stop point information regarding a contact stop point based on a detection result of the second sensor. The characteristic-vibration-information extraction section extracts a characteristic vibration information regarding a predetermined characteristic vibration and determines a position of the characteristic vibration.