Workpiece Processing Apparatus with Real-Time Mark Inspection
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Solution Overview
Problem
The existing processing methods for workpieces, such as semiconductor wafers, result in a significant number of unacceptable products due to process marks, leading to low yield and unnecessary discarding of device chips.
Innovation Solution
A processing apparatus and method that includes a chuck table, processing unit, movement units, an inspection unit to detect process marks, and a dressing unit to re-dress the grinding or polishing tools when marks exceed a threshold, allowing for continuous processing without discarding workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all workpieces with process marks are discarded as unacceptable products, then the quality of finished products is maintained, but the yield of device chips cannot be raised sufficiently
Solution Approach 1:
The inspection unit performs real-time detection of process marks during the grinding or polishing process. When a process mark is detected, the system stops processing and dresses the grinding whetstone or polishing pad before continuing. This preliminary action prevents process marks from developing into defects that would require discarding the workpiece, thereby maintaining product quality while improving yield.
Solution Approach 2:
The system implements a feedback mechanism where the inspection unit continuously monitors the workpiece surface during processing. When a process mark is detected, this information is fed back to the control unit, which then triggers the dressing unit to dress the grinding or polishing tool. This closed-loop feedback system ensures that process marks are addressed immediately, preventing them from becoming unacceptable defects and allowing the workpiece to be saved.
2Manufacturing precision
If the grinding whetstone or polishing pad is dressed frequently to prevent process marks, then the quality of workpiece surface is improved, but the processing time increases
Solution Approach 1:
The inspection unit provides real-time feedback on the condition of the workpiece surface during processing. Instead of dressing the grinding whetstone or polishing pad at fixed intervals, the system dresses only when a process mark is detected. This feedback-based approach maintains high surface quality while minimizing unnecessary dressing operations, thereby reducing total processing time.
Solution Approach 2:
The system employs self-service dressing, where the dressing unit automatically dresses the grinding whetstone or polishing pad in response to detected process marks without requiring manual intervention. The dressing is performed in-situ during the processing cycle, eliminating the need for separate dressing operations and reducing overall processing time while maintaining surface quality.
3Productivity
If real-time inspection and dressing operations are implemented, then the yield of workpieces is improved, but the device complexity increases
Solution Approach 1:
The inspection unit, dressing unit, and processing unit are merged into a single integrated system. The inspection unit is positioned to monitor the workpiece during processing, and the dressing unit is integrated with the grinding or polishing mechanism. This merging of functions reduces the need for separate standalone devices and simplifies the overall system architecture while enabling real-time inspection and dressing to improve yield.
Solution Approach 2:
The dressing unit is designed to be universal, capable of dressing both grinding whetstones and polishing pads using the same basic mechanism. The inspection unit also serves multiple purposes by detecting both process marks and the condition of the grinding or polishing tool. This multi-functionality reduces the number of specialized components needed, thereby reducing system complexity while maintaining high yield through real-time monitoring and dressing.
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 minimizes the number of workpieces discarded as unacceptable products by detecting and addressing process marks in real-time, thereby enhancing the yield of device chips.
Implementation Method 1
an inspection unit configured to inspect a process mark of the workpiece during processing by the processing unit
Implementation Method 2
a dressing unit configured to dress the grinding whetstone or the polishing pad of the processing unit
Data Source
AI summary
A processing apparatus includes a chuck table that holds a workpiece by a holding face, a processing unit that processes the workpiece with a grinding whetstone or a polishing pad, a movement unit for moving the chuck table and the processing unit parallel to the holding face, a processing feeding unit for moving the chuck table and the processing unit in a direction orthogonal to the holding face, an inspection unit to inspect a process mark of the workpiece during processing, a dressing unit to dress the grinding whetstone or the polishing pad of the processing unit, and a control unit. When a process mark of a size exceeding a threshold value is detected on the process face of the workpiece, the control unit stops processing of the workpiece, and after the grinding whetstone or the polishing pad is dressed, restarts processing.