Wire Guide Roller Groove Spacing for Uniform Disc Thickness

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Solution Overview

Problem

Existing wire sawing methods struggle to achieve a narrow distribution of disc thickness, which is crucial for subsequent processing steps like lapping, grinding, and polishing, as the thickness of slices cut from semiconductor wafers often deviates significantly, leading to uneven material removal and processing inefficiencies.

Innovation Solution

A method involving wire guide rollers with a non-linear distance function that adjusts groove spacing based on previous cutting processes' thickness parameters, ensuring a target thickness characteristic is maintained by calculating the distance function dTAR(WP) as dINI(WP) + TTAR(WP) - TINI(WP), where dINI(WP) accounts for initial groove distances, TTAR(WP) sets target thickness, and TINI(WP) measures previous cutting process thickness, thereby optimizing groove spacing for consistent slice thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If uniform groove spacing is used in wire guide rollers, then the device structure is simple, but the slice thickness distribution is wide and non-uniform

Engineering Contradiction:
Improveslice thickness uniformityVSAvoidgroove spacing configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The wire guide rollers are configured with non-uniform groove spacing where different sections of the roller have different groove pitch values. Specifically, the groove spacing varies along the axial direction of the roller, with closer spacing in regions that produce thinner slices and wider spacing in regions that produce thicker slices. This local variation in groove quality directly compensates for the natural thickness variation in slices, achieving uniform thickness distribution without complex additional devices.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If wire guide rollers with adjusted groove spacing are used, then slice thickness uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improveslice thickness distributionVSAvoidwire guide roller configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the geometric parameter of groove spacing in the wire guide rollers from a uniform value to a non-uniform distribution. By adjusting the groove pitch parameter along the axial direction of the rollers, the system compensates for thickness variations in slices. This parameter change is implemented directly in the roller design without adding complex control systems or multiple adjustable components, thus improving precision while limiting complexity increase.

Inventive Principle:
Principle #35Parameter changes

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 results in a more uniform distribution of slice thickness, reducing variance and improving the economic efficiency of subsequent processing by ensuring disks meet the required flatness and plane parallelism standards, minimizing material waste and processing issues.

Implementation Method 1

Relative movement in the presence of an abrasive material causes material to be removed from the workpiece upon contact with the wire saw

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

Rotating the wire guide rollers generates a relative movement between the wire segments and the workpiece

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3943265A1Method and device for simultaneously separating a plurality of plates from a workpiece
Publication Date: 2022.01.26 SILTRONIC AG
  • EP3943265A1 patent drawingFigure 1
  • EP3943265A1 patent drawingFigure 2
  • EP3943265A1 patent drawingFigure 3

AI summary

Method and wire saw for simultaneously cutting off a large number of discs from a workpiece during a cutting process.The method is characterized in that a non-linear distance function dTAR(WP) is selected depending on a target thickness parameter function TTAR(WP), a distance function dINI(WP), and a thickness parameter function TINI(WP), wherein dTAR(WP) assigns a distance to adjacent grooves in the surface of the wire guide rollers at a position WP during the cutting process, wherein TINI(WP) assigns a thickness parameter measured on the discs to discs obtained at position WP during several previous cutting processes using the wire saw, wherein dINI(WP) assigns a distance to adjacent grooves in the surface of the wire guide rollers at position WP during the previous cutting processes, wherein TTAR(WP) assigns a target thickness parameter to discs cut off at position WP during the cutting process, and wherein WP is the axial position of the adjacent grooves with respect to the axes of the Wire guide rollers are referred to.