Wire Slicing Tension Adjustment for Semiconductor Wafer Reuse
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Solution Overview
Problem
Reducing the new wire supply amount for slicing semiconductor wafers increases wire abrasion and reduces wire diameter, leading to degraded wafer quality, increased warp, and higher breakage rates, which lowers production efficiency and increases costs.
Innovation Solution
A workpiece slicing method that reuses a wire by adjusting wire tension to 87-95% of the previous value and increasing the new wire supply amount to 125% or more, while maintaining appropriate workpiece feed rates, to minimize wire breakage and warp degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the new wire supply amount is reduced to increase the number of workpieces sliced per wire reel bobbin, then wire cost decreases, but wire abrasion increases and wire diameter becomes small leading to degraded wafer quality
Solution Approach 1:
The patent applies parameter changes by adjusting wire tension to 87-95% of the previous value and increasing the new wire supply amount to 125% or more when reusing wire. This resolves the contradiction by modifying operational parameters to maintain wire diameter and quality while enabling extended wire usage for slicing more workpieces.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting wire tension and wire supply amount based on wire reuse status. The system transitions from fixed parameter operation to adaptive parameter control, allowing the wire slicing system to maintain optimal performance throughout extended wire usage cycles.
2Quantity of substance
If the new wire supply amount is reduced, then wire cost decreases, but wire breakage rate increases due to increased abrasion and reduced wire diameter
Solution Approach 1:
The patent changes operational parameters by reducing wire tension to 87-95% of the original value and increasing wire supply to 125% or more during wire reuse. This resolves the contradiction by creating operational conditions that reduce stress on abraded wire while maintaining slicing effectiveness, thereby preventing breakage.
Solution Approach 2:
The patent applies beforehand cushioning by pre-adjusting wire tension downward before reuse and increasing wire supply in advance. This preparatory parameter adjustment cushions the wire against excessive stress and abrasion that would otherwise lead to breakage during extended usage.
3Quantity of substance
If the new wire supply amount is reduced, then wire cost decreases, but wafer warp increases due to reduced slurry carrying-in amount
Solution Approach 1:
The patent applies parameter changes by increasing the new wire supply amount to 125% or more when reusing wire. This ensures sufficient slurry carrying-in amount is maintained despite wire diameter reduction, thereby preventing increased wafer warp while enabling extended wire usage.
4Productivity
If wire tension is maintained at previous levels during wire reuse, then slicing efficiency is maintained, but wire breakage occurs due to increased abrasion
Solution Approach 1:
The patent changes wire tension parameter to 87-95% of the previous value during wire reuse. This parameter adjustment resolves the contradiction by reducing tension to compensate for increased abrasion and reduced wire diameter, preventing breakage while maintaining acceptable slicing efficiency through the combined effect of adjusted tension and increased wire supply.
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 method significantly increases the number of wafers that can be sliced per wire reel bobbin, reduces wire breakage and wafer warp, and maintains wafer quality, thereby lowering wire costs and improving production efficiency.
Implementation Method 1
presses a workpiece (e.g., a silicon ingot) against the wire to be sliced while applying slurry to the wire so that many wafers are simultaneously sliced out
Data Source
AI summary
A method for slicing workpiece reusing a wire used for previous slicing of a workpiece to slice a subsequent workpiece by which the workpiece is pressed against a wire row and sliced, the wire row being formed of the wire spirally wound between a plurality of wire guides and travels in an axial-direction, where wire tension at the time of slicing the workpiece is set to a value in the range of 87 to 95% of wire tension in the previous slicing of the workpiece, a new wire supply amount at the time of slicing the workpiece is set to a value in the range of 125% or more of a new wire supply amount in the previous slicing of the workpiece, and the wire is reused to slice the subsequent workpiece.