Wafer Edge Trimming Control Using Real-Time Thickness Feedback
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in accurately controlling the edge trimming depth of semiconductor wafers due to blade abrasion and varying thickness, leading to inconsistent trimming depths and potential chipping near semiconductor elements.
Innovation Solution
A semiconductor manufacturing apparatus equipped with a rotatable table, a sensor to measure the wafer thickness, and a control unit that adjusts the blade's movement and rotation based on real-time thickness measurements, ensuring precise edge trimming by monitoring and adjusting the thickness during machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a blade is used for edge trimming of semiconductor wafers, then the outer peripheral end part can be removed, but the trimming depth becomes inconsistent due to blade abrasion
Solution Approach 1:
A sensor detects the actual thickness of the semiconductor wafer during the edge trimming process, and this detection information is fed back to a control unit. The control unit adjusts the blade position or machining parameters in real-time based on the detected thickness, ensuring consistent trimming depth despite blade abrasion. This closed-loop feedback mechanism resolves the contradiction by dynamically compensating for blade wear.
Solution Approach 2:
The system performs preliminary measurement of the semiconductor wafer thickness before and during the edge trimming process using a sensor. Based on this preliminary detection, the control unit pre-adjusts the blade positioning or machining parameters to compensate for expected variations, ensuring consistent trimming depth from the outset rather than relying on post-processing adjustments.
2Productivity
If the blade machining depth is increased to remove more material, then edge trimming efficiency improves, but the risk of chipping near semiconductor elements increases
Solution Approach 1:
The system performs multiple passes of edge trimming with progressively deeper cuts rather than attempting to remove all material in a single deep cut. Each pass removes a portion of the outer peripheral end part, gradually achieving the target depth while keeping each individual cutting depth within safe limits that prevent chipping. This staged approach balances productivity with damage prevention.
Solution Approach 2:
The sensor continuously monitors the wafer thickness during machining, providing real-time feedback to the control unit. When the detected thickness approaches a safe threshold near semiconductor elements, the control unit automatically reduces the blade depth or stops the machining process, preventing chipping while maximizing material removal in earlier stages.
3Manufacturing precision
If real-time thickness measurement and adjustment systems are added, then trimming precision improves, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical measurement and adjustment mechanisms with a sensor-based detection system and automated control unit. Instead of using elaborate mechanical gauges and manual adjustment devices, the patent employs electronic sensors to detect thickness and an automated control system to adjust blade positioning, simplifying the overall device structure while maintaining high precision.
Solution Approach 2:
The control unit automatically adjusts the blade positioning and machining parameters based on sensor feedback without requiring manual intervention. The system serves itself by autonomously detecting thickness variations and making necessary adjustments, eliminating the need for complex manual adjustment mechanisms and reducing overall system complexity.
Data Source
AI summary
A semiconductor manufacturing apparatus according to the present embodiment includes a table, a shaft, a sensor, and a first control unit. The table has a first surface on which a processing target object is placed, and is rotatable about a rotational axis in a first direction substantially orthogonal to the first surface. The shaft rotatably and movably holds a blade that machines the processing target object. The sensor measures a thickness of processing target object in a region to be machined by the blade. The first control unit controls rotation and movement of the shaft. The first control unit controls movement of the blade in the first direction based on a result of the measurement by the sensor.