Wire Guide Roller Jacket Thermal Expansion Compensation

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Solution Overview

Problem

The production of semiconductor wafers requires precise cutting with minimal thermal expansion of wire guide rollers to maintain flatness, as existing methods fail to effectively control thermal expansion of both the core and jacket materials, leading to alignment errors and impaired wafer geometry.

Innovation Solution

A method involving wire guide rollers with a core and jacket of different materials, where the jacket's length is thermally altered using temperature-regulating cavities to compensate for thermally induced changes in the workpiece, maintaining precise alignment and geometry of the cut wafers by synchronizing the expansion of the jacket with the workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If wire guide rollers are used during the sawing process, then the wire web is properly guided and wafers are produced, but thermal expansion of the roller jacket causes alignment errors and wafer geometry impairment

Engineering Contradiction:

Improvewafer geometry and flatnessVSAvoidthermal expansion of jacket

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent changes the physical state of the jacket material by transforming it from a rigid structure to a flexible membrane that can be inflated or deflated. This parameter change allows the jacket to adapt its dimensions dynamically, compensating for thermal expansion and maintaining alignment precision during the sawing process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic adjustability to the wire guide roller jacket by using an inflatable membrane structure. The jacket can be inflated or deflated during operation to compensate for thermal expansion, transforming a static component into a dynamic one that adapts to changing conditions and maintains manufacturing precision.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If the wire guide roller jacket is rigid to maintain structural stability, then the roller provides consistent guidance, but thermal expansion causes alignment errors and wafer curvature

Engineering Contradiction:

Improvestructural stability of wire guide rollerVSAvoidalignment precision and wafer flatness

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent replaces the rigid jacket with a flexible membrane structure that can be inflated or deflated. This flexible shell maintains structural stability when inflated while allowing dimensional adjustment to compensate for thermal expansion, thereby preserving both stability and alignment precision during operation.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

3Temperature

If cooling measures are applied to reduce thermal expansion, then temperature increase is limited, but alignment precision is still insufficient due to residual expansion

Engineering Contradiction:

Improvetemperature control of wire guide rollerVSAvoidalignment precision

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent replaces the thermal management approach (cooling measures) with a mechanical compensation approach (inflatable membrane). Instead of trying to prevent thermal expansion through cooling, the system mechanically compensates for the expansion by inflating the membrane to maintain proper alignment, achieving superior precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies preliminary anti-action by pre-inflating the membrane or adjusting its pressure before thermal expansion occurs. This proactive compensation counteracts the expected thermal expansion, maintaining alignment precision throughout the sawing process rather than reacting after expansion has occurred.

Inventive Principle:

Principle #9Preliminary anti-action

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 improves the geometry and waviness of the wafers by continuously adapting the jacket's length to match the workpiece's thermal expansion, resulting in significantly better surface profiles and reduced curvature along the wafer diameter.

Implementation Method 1

compensating for thermally induced change in length of a workpiece by means of a likewise thermally induced change in length of the wire guide rollers spanning the wire web, in particular of the jacket enclosing the lateral surface of the core

Methodology Applied

Scientific EffectThermal expansion compensation: Thermal Expansion

Data Source

PatentUS9662804B2Method for slicing wafers from a workpiece by means of a wire saw

Publication Date: 2017.05.30 SILTRONIC AG

AI summary

A method for sawing a multiplicity of wafers from a workpiece by means of a wire web of a wire saw includes providing a wire web consisting of a plurality of parallel wire sections. The wire web is spanned by at least two wire guide rollers where each wire guide rollers comprises a core having two side surfaces and a lateral surface. The core is composed of a first material. Each core is rotatably mounted along its longitudinal axis and comprises at least two separate cavities. The lateral surface of each core is enclosed by a jacket composed of a second material. Parallel groves are cut into the jacket for guiding the wire sections of the web. The length of the jacket is altered thermally by means of at least one cavity being filled with a temperature regulating medium.