Structured Wire Guide Grooves for Uniform Disc Slicing

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Solution Overview

Problem

Existing wire saw technologies are unsuitable for using structured wires, leading to frequent wire breaks, uneven cutting, and poor flatness/thickness uniformity of discs, which are not suitable for high-demand applications like semiconductor substrates.

Innovation Solution

The method involves using structured wires with specific groove designs and radii of curvature that adjust to the changing effective diameter of the wire, ensuring optimal guidance and minimizing wear, while maintaining tension and torsion to prevent wire breaks and ensure consistent disc quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional wire saw technologies are used with structured wires, then wire breaks occur frequently, but using structured wires with specific groove designs prevents wire breaks and maintains consistent disc quality

Engineering Contradiction:
Improvewire break preventionVSAvoidgroove design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wire guide roller is designed with grooves that have different radii of curvature at different locations. Specifically, the groove has a first radius of curvature at the entrance and a second, larger radius of curvature at the exit. This local variation in groove geometry optimizes wire guidance and reduces stress concentrations that cause wire breaks, while maintaining overall system simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove design adapts to the changing effective diameter of the wire as it wears during operation. By incorporating varying radii of curvature along the groove path, the system dynamically accommodates wire diameter reduction, maintaining optimal wire guidance and tension throughout the wire's service life, thereby preventing wire breaks.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If conventional groove designs are used, then disc thickness and flatness are uneven, but optimized groove designs achieve consistent disc quality

Engineering Contradiction:
Improvedisc thickness and flatness uniformityVSAvoidgroove geometry complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The groove geometry is optimized with specific radii of curvature at different locations to achieve uniform disc thickness and flatness. The first radius of curvature at the groove entrance and the second, larger radius at the groove exit create optimal wire contact conditions throughout the cutting process, ensuring consistent material removal and disc quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove design incorporates specific geometric parameters (radii of curvature) that are optimized for structured wires. By carefully selecting and varying these geometric parameters along the groove path, the system achieves precise control over wire contact and material removal, resulting in uniform disc thickness and flatness.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If standard wire guide rollers are used, then wear on rollers is high, but optimized groove designs reduce wear on wire guide rollers

Engineering Contradiction:
Improvewire guide roller service lifeVSAvoidgroove design complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The groove design distributes wire contact forces more evenly by incorporating varying radii of curvature. This local optimization of groove geometry reduces stress concentrations and minimizes wear at critical locations, extending the service life of the wire guide roller while maintaining relatively simple overall structure.

Inventive Principle:
Principle #3Local quality

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 prevents wire breaks, achieves consistent disc thickness and flatness, and reduces wear on wire guide rollers, resulting in high-quality, uniform discs suitable for demanding applications like semiconductor substrates.

Implementation Method 1

By advancing the bar perpendicularly to the gate, the wire sections come into contact with the bar and exert a force on the bar as the bar continues to be advanced. Hard materials, force and relative movement cause material to be removed from the rod

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3582920B1Wire saw and method for simultaneously separating a plurality of discs from a rod
Publication Date: 2022.08.10 SILTRONIC AG
  • EP3582920B1 patent drawingFigure 1(A)~1(D)
  • EP3582920B1 patent drawingFigure 2~3
  • EP3582920B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for simultaneously separating a plurality of discs from a rod using a structured saw wire (2). The structured saw wire (2) is guided by grooves (9, 10) of two wire guide rollers (14), and the base of each groove (9, 10) on which the structured wire (2) rests has a curved groove base (16) with a curvature radius which, in the case of each groove (9, 10), is equal to or up to 1.5 times larger than the radius of the structured wire (2) envelope that the structured wire (2) has in each groove (9, 10). The invention additionally relates to a wire guide roller (14) and to a wire saw.