Chuck Table Height Mapping for Precise Cutting Depth Control
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Solution Overview
Problem
The accuracy of cutting depth in processing apparatuses is compromised due to variations in the height and inclination of chuck table holding surfaces, leading to potential decreases in processing quality when the chuck table is replaced.
Innovation Solution
A processing apparatus with a chuck table that includes a height measuring unit, a reading unit for identifying information, and a control unit to record and utilize height data for precise control of processing units, ensuring consistent cutting depth accuracy across the entire surface, even when the chuck table is replaced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If one origin position is applied to the entire holding surface, then the setup process is simplified, but cutting depth accuracy deteriorates due to height variations and inclination
Solution Approach 1:
The holding surface is divided into multiple measurement regions with multiple origin positions registered across the surface. Each region has its own height measurements and origin position, allowing local compensation for height variations and inclination rather than using a single origin for the entire surface.
Solution Approach 2:
Height measurements are taken at multiple coordinates across the holding surface and stored in association with coordinate information. This feedback data is used to compensate for height variations and inclination, enabling accurate cutting depth control by referencing the measured height map rather than assuming a uniform surface.
2Manufacturing precision
If origin positions are registered on the entire surface of the chuck table, then cutting depth accuracy is improved, but the system complexity increases
Solution Approach 1:
An information medium (storage device) is introduced to store the height measurement data and coordinate associations. This intermediary allows the system to maintain complex height maps without increasing the physical complexity of the measurement and control system, as data is stored and retrieved rather than processed in real-time through complex hardware.
Solution Approach 2:
The height information and origin position data are copied into an information medium for storage and retrieval. Instead of maintaining complex real-time measurement systems, the patent uses stored copies of height data that can be quickly accessed during processing operations.
3Adaptability or versatility
If the chuck table is replaced for processing different wafers or periodic inspection, then processing versatility is improved, but cutting depth accuracy deteriorates
Solution Approach 1:
Each chuck table is equipped with an information medium that stores its own height measurement data and identifying information. When a chuck table is installed, the reading unit automatically reads its identifying information and retrieves or measures its height data, allowing the table to self-configure without requiring manual setup or calibration by the operator.
Solution Approach 2:
The patent replaces manual setup and mechanical calibration processes with an automated information-based system. The reading unit automatically reads identifying information from the chuck table's information medium, and the control unit automatically retrieves or measures height data and applies corrections, eliminating the need for manual origin positioning and calibration.
Data Source
AI summary
A processing apparatus includes a chuck table, a processing unit configured to process a workpiece held on the chuck table, a height measuring unit fitted to the processing unit, the height measuring unit measuring, as height data, heights at a plurality of coordinates of the holding surface measured while a moving unit is moved, a reading unit capable of reading an information medium, and a control unit. The chuck table includes an information medium on which identifying information distinguishing the chuck table is recorded. The control unit includes a height data recording section configured to record the height data and the identifying information in association with each other, and a processing control section configured to control a height of the processing unit during processing on the basis of the height data associated with the identifying information read by the reading unit.