Structured Saw Wire Spool Rotation for Wafer Thickness Control
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Solution Overview
Problem
Structured saw wires used for cutting hard and brittle materials often experience preferential crimp direction issues, leading to increased total thickness variation and saw marks due to lack of circular symmetry, which affects the quality of cut wafers.
Innovation Solution
A spool with saw wire featuring two or more crimp deformations perpendicular to the longitudinal axis, combined with elastic and/or plastic rotations, to prevent preferential direction and enhance abrasive transport and swarf evacuation, resulting in improved wafer surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If structured saw wires with crimps in at least two different planes are used, then abrasive transport is improved and swarf evacuation is enhanced, but preferential crimp direction develops leading to increased total thickness variation and saw marks
Solution Approach 1:
The patent applies asymmetry by introducing elastic and plastic rotations to the structured saw wire, creating a non-symmetric configuration that prevents the wire from settling into a preferential crimp direction during sawing, thereby maintaining uniform material removal and reducing total thickness variation
Solution Approach 2:
The patent introduces dynamic characteristics by incorporating elastic rotations that allow the saw wire to flex and adapt during operation, preventing rigid preferential direction development while maintaining the structured configuration benefits for abrasive transport and swarf evacuation
2Productivity
If structured saw wires with crimps are used, then abrasive transport and swarf evacuation are improved, but wire complexity increases
Solution Approach 1:
The patent segments the wire structure into distinct crimps arranged in at least two different planes with different wavelengths, creating a modular structured configuration that improves abrasive transport and swarf evacuation while managing complexity through organized segmentation
Solution Approach 2:
The patent changes structural parameters by varying the wavelength of crimps in different planes and introducing elastic and plastic rotations, optimizing the balance between structural complexity and sawing performance
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
The solution ensures better wafer surface quality by preventing crimp direction dominance and improving abrasive transport, leading to reduced wear and increased throughput with less wire usage.
Implementation Method 1
The saw wire has at least two elastic rotations per unit length that are applied in the elastic rotation direction
Implementation Method 2
The saw wire has at least two plastic rotations per unit length that are applied in the plastic rotation direction
Implementation Method 3
The abrasive particles are dragged by the saw wire and abrade away the material of the work piece
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3a~3c
AI summary
A spool of saw wire is disclosed. The saw wire is wound on the core of the spool (718). The saw wire is made of steel wire (406) wherein two or more crimp deformations are implemented. Each of said two or more crimp deformations has a crimp direction that is perpendicular to the longitudinal axis. Each of the crimp directions is different from the other crimp directions. The saw wire on the spool comprises a number of elastic rotations per unit length applied in the elastic rotation direction. The spool with saw wire can give excellent processability in the sawing process.