Wire Saw Self-Dressing for Uniform Wafer Thickness
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Solution Overview
Problem
Fixed abrasive grain type wire saws face issues with initial wafer thickness unevenness due to abrasive grain wear and vibration, requiring costly and complex dressing methods to maintain sharpness and reduce thickness variation.
Innovation Solution
Incorporating an abrasive-grain abrading step where the fixed abrasive grain wire rubs against itself within the wire reels for 30 minutes or more before slicing, with a winding tension of 15 N or more, to dress the wire and suppress wafer thickness unevenness without the need for new equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed abrasive grain wire is used for slicing a workpiece, then the workpiece can be sliced efficiently, but the abrasive grains wear out quickly at the start of slicing, causing wafer thickness unevenness
Solution Approach 1:
The patent applies preliminary action by dressing the abrasive grains on the fixed abrasive grain wire before the slicing operation begins. This pre-dressing sharpens the abrasive grains in advance, ensuring they maintain sufficient sharpness during the initial slicing phase, thereby preventing wafer thickness unevenness while preserving slicing efficiency throughout the process
2Manufacturing precision
If the abrasive grains are dressed before slicing to maintain sharpness, then wafer quality improves, but the dressing process requires new equipment or remodeling, increasing cost and complexity
Solution Approach 1:
The patent employs self-service by enabling the fixed abrasive grain wire to dress its own abrasive grains through friction against a dressing surface during the slicing process. This self-dressing mechanism eliminates the need for separate dressing equipment or system remodeling, maintaining wafer quality while avoiding increased device complexity and cost
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 method effectively dresses the fixed abrasive grain wire, reducing wafer thickness unevenness and allowing for cost-effective, easy implementation, as demonstrated by improved thickness uniformity in sliced wafers.
Implementation Method 1
the fixed abrasive grain wire is allowed to travel without slicing the workpiece, thereby allowing the fixed abrasive grain wire to rub against itself within the wire reels, and dressing the surface of the fixed abrasive grain wire
Data Source
AI summary
A method for slicing a workpiece with a wire saw which includes a wire row formed by winding a fixed abrasive grain wire having abrasive grains secured to a surface thereof around a plurality of grooved rollers, the wire being fed from one of a pair of wire reels and taken up by another, the method including feeding a workpiece to the row for slicing while allowing the wire to reciprocate and travel in an axial direction, thereby slicing the workpiece at a plurality of positions aligned in an axial direction of the workpiece simultaneously. Prior to slicing, an abrasive-grain abrading step wherein the wire is allowed to travel without slicing the workpiece, allowing the wire to rub against itself within the reels, and dressing its surface for 30 minutes or more. The method can dress a fixed abrasive grain wire at low cost and suppress thickness unevenness of wafers.