Wire Saw Ingot Slicing Feed Control
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Solution Overview
Problem
The existing wire saw technology results in significant thickness unevenness between wafers sliced from the first ingot and subsequent ingots after wire replacement due to differences in wire diameter, leading to inefficiencies in post-processing and reduced productivity.
Innovation Solution
A method and apparatus where the wire new line feed ratio at the slicing start portion to the central portion is controlled to be ½ or less for the first ingot compared to subsequent ingots, using spirally wound wire rows and precise ingot feeding with a working fluid, to minimize thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wire diameter is reduced at the slicing start portion by abrasing the wire, then thickness unevenness is decreased, but additional processing time and complexity are required
Solution Approach 1:
The patent applies dynamics by making the wire new line feed amount variable rather than constant. The feed amount is dynamically adjusted based on the slicing position along the ingot length, with smaller feed amounts at the start portion and larger feed amounts at the central portion. This dynamic control is achieved through a programmable wire feed mechanism that automatically adjusts parameters during slicing, reducing the need for complex manual intervention while maintaining precision.
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 reduces thickness unevenness between wafers from the first and subsequent ingots to a comparable level, allowing for uniform processing conditions and improved productivity in post-processing steps like lapping.
Implementation Method 1
a wire (a high tensile steel wire) to travel at high speed, presses a workpiece (there is, e.g., a silicon ingot) against the wire while apply slurry to the wire, and slices the workpiece
Implementation Method 2
supplying a working fluid to a contact portion of the ingot and the wire
Data Source
AI summary
A method is disclosed for slicing an ingot by which wire rows are formed by using a wire that is spirally wound between a plurality of wire guides and travels in an axial direction. An ingot is pressed against the wire rows while supplying a working fluid to a contact portion of the ingot and the wire, thereby slicing the ingot into wafers, and a ratio of a wire new line feed amount per unit time in slicing of a slicing start portion of a first ingot to that in slicing of a centration portion of the same at the time of slicing the ingot after replacement of the wire is controlled to be ½ or less of the ratio at the time of slicing second and subsequent ingots after the replacement of the wire.