Wire Saw Slicing Thermal Flatness Control
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Solution Overview
Problem
Existing wire slicing lapping methods for semiconductor wafers and other materials face issues with thermal-induced flatness deviations and parallelism problems due to non-uniform heat input and abrasive depletion during the cutting process, leading to unsuitable slices for demanding applications, especially with larger workpieces.
Innovation Solution
A method and apparatus that alternates the direction of wire rotation and uses strategically positioned nozzles to spray coolant and abrasive, ensuring uniform temperature regulation and abrasive distribution across the cutting gap, thereby compensating for rapid temperature fluctuations and maintaining consistent slice thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wire slicing lapping is used to slice semiconductor wafers, then slices can be produced efficiently, but thermal-induced flatness deviations and parallelism problems occur due to non-uniform heat input
Solution Approach 1:
The wire is segmented into multiple parallel wire sections that run through the workpiece simultaneously, allowing distributed cutting action that reduces localized heat concentration and improves uniformity of temperature distribution across the slicing zone
Solution Approach 2:
The wire rotation direction is periodically reversed during the slicing process, which alternates the direction of heat input and prevents thermal accumulation on one side, thereby reducing thermal-induced flatness deviations and parallelism errors
Solution Approach 3:
The method changes the operational parameters by alternating wire rotation direction and adjusting slicing speed, which modifies the heat input pattern to achieve more uniform temperature distribution and improve slice flatness and parallelism
2Ease of manufacture
If conventional wire slicing lapping is used, then slicing can be performed, but abrasive depletion occurs during the cutting process leading to inconsistent slice thickness
Solution Approach 1:
Multiple wire sections operate simultaneously and continuously through the workpiece, ensuring continuous abrasive action throughout the cutting zone and preventing abrasive depletion that would otherwise occur with single-wire methods, thereby maintaining consistent slice thickness
Solution Approach 2:
The cutting action is segmented across multiple parallel wire sections, distributing the abrasive consumption across all sections and ensuring continuous fresh abrasive contact with the workpiece, which prevents thickness variation caused by abrasive depletion
3Productivity
If single-wire multiple slicing lapping is used, then a multiplicity of slices can be sliced simultaneously, but rapid temperature fluctuations occur causing thermal-induced undulations
Solution Approach 1:
The wire rotation direction is periodically reversed during slicing, which alternates the heat input pattern and compensates for rapid temperature fluctuations, thereby reducing thermal-induced undulations while maintaining the ability to slice multiple slices simultaneously
Solution Approach 2:
The system dynamically changes the wire rotation direction during the slicing process, adapting the cutting action to compensate for thermal effects and maintain flatness precision even when producing multiple slices per cut
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 significantly reduces thermal-induced undulations and improves the flatness and parallelism of sliced materials, making them suitable for larger workpieces by maintaining uniform temperature and abrasive distribution across the cutting zone.
Implementation Method 1
The wire sections are guided by rotation of the wire guide rolls with continual change in direction of rotation from an entry side to an exit side through the workpiece
Implementation Method 2
supplying a slurry of hard substances in a carrier liquid as abrasive to the wire sections
Implementation Method 3
chip removal or chipping is understood to mean, according to DIN 8580, mechanical machining methods in which material is brought to the desired form by removing excess material in the form of chips
Implementation Method 4
spraying a coolant from the side and from below into slicing gaps that arise during the relative movement of the workpiece through the web
Implementation Method 5
ensuring uniform temperature regulation and abrasive distribution across the cutting gap
Data Source
AI summary
A method and apparatus are used to simultaneously slice a multiplicity of slices from a workpiece. The workpiece is held with a feed device so as to position an axis of the workpiece parallel to axes of wire guide rolls of a wire saw and is moved from above through a web of the wire saw. A slurry is supplied as abrasive to wire sections of the web while the wire sections are moved relative to the workpiece. The relative movement guides the wire sections from an entry side to an exit side through the workpiece. A coolant is sprayed from the side and below through nozzles into slicing gaps in the workpiece. The nozzles are arranged below the web parallel to the axes of the wire guide rolls. The coolant is sprayed into the slicing gaps through a nozzle situated opposite the entry side of the respective wire section.