Workpiece Chuck Tilt Control for Grinding Stone Sharpness
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Solution Overview
Problem
In semiconductor manufacturing, fine grinding processes are interrupted for thickness measurements, leading to a deterioration in grinding stone sharpness, resulting in unstable workpiece shapes and potential surface burns due to insufficient dressing of the grinding stone.
Innovation Solution
A processing system that includes a tilting device for the workpiece chuck, a non-contact film thickness measurement device, and a control system to calculate and apply a tilt angle for reprocessing, ensuring pre-grinding and fine grinding are performed with the chuck tilted, maintaining grinding stone sharpness and achieving high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fine grinding is temporarily stopped to measure workpiece thickness, then measurement accuracy is improved, but grinding stone sharpness deteriorates
Solution Approach 1:
The system performs pre-grinding before fine grinding to preliminarily dress the grinding stone and prepare its surface. This preliminary action ensures the grinding stone is properly conditioned before the fine grinding operation, preventing sharpness deterioration even when measurement interruptions occur.
Solution Approach 2:
The system continuously dresses the grinding stone through the pre-grinding process that runs before and between fine grinding operations. This continuous dressing action maintains grinding stone sharpness throughout the manufacturing process, eliminating the harmful effect of sharpness deterioration during measurement interruptions.
2Productivity
If fine grinding is resumed after thickness measurement, then productivity is improved, but workpiece surface quality deteriorates
Solution Approach 1:
Pre-grinding is performed as a preliminary action before fine grinding to prepare the grinding stone surface. This preliminary dressing ensures the grinding stone is properly conditioned, allowing fine grinding to proceed efficiently without causing surface burns or quality deterioration.
Solution Approach 2:
The system changes the operational parameters by introducing a tilt angle adjustment to the chuck during pre-grinding. This parameter change optimizes the grinding conditions, ensuring proper dressing of the grinding stone while maintaining productivity and surface quality in subsequent fine grinding operations.
3Manufacturing precision
If grinding stone is fine-grained, then workpiece surface finish is improved, but grinding stone sharpness deteriorates
Solution Approach 1:
The system performs pre-grinding as a preliminary action that dresses the fine-grained surface of the grinding stone. This preliminary dressing restores and maintains the sharpness of the fine-grained surface, allowing the grinding stone to both achieve excellent surface finish and maintain reliable sharpness during operation.
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 configuration allows for efficient and accurate processing of workpieces by maintaining grinding stone sharpness and stabilizing workpiece shapes, reducing thickness variations and preventing surface burns.
Implementation Method 1
a measurement device that measures a film thickness of the workpiece after fine grinding in a non-contact manner
Data Source
AI summary
A processing system capable of processing a workpiece with high accuracy. A tilting device capable of tilting a rotation axis 3a of a chuck 3 holds a workpiece W. A film thickness measurement device 7 measures a film thickness of the workpiece W after fine grinding in a non-contact manner. A control device 8 operates a shape of the workpiece W after fine grinding on the basis of a measurement value of the film thickness measurement device 7, calculates a tilt angle of the tilting device such that a difference between a maximum thickness and a minimum thickness of the workpiece W after the fine grinding decreases, and tilts the chuck 3 by the tilt angle such that the workpiece W after the fine grinding is reprocessed by rough grinding, intermediate grinding, and fine grinding in this order with the chuck 3 tilted by the tilt angle.