Wire Saw Resumption via Dummy Workpiece Diameter Matching
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Solution Overview
Problem
Wire breaks during semiconductor ingot slicing with a wire saw lead to increased production of inferior wafers due to diameter differences between the broken wire and the new line, causing groove formation that subsequent processes often cannot remove.
Innovation Solution
A method to resume wire saw operation by matching the diameter of the repaired wire to the diameter of the wire just before the break, using a dummy workpiece to wear the wire to the correct diameter without detaching the original workpiece, thus preventing groove formation in sliced wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wire is repaired by connecting broken portions and pulling to a new position, then the wire saw operation can be resumed, but the diameter of the repaired wire differs from the original wire causing groove formation in wafers
Solution Approach 1:
The patent applies preliminary action by introducing a dummy workpiece before resuming actual wafer slicing. The wire is worn on the dummy workpiece to restore its diameter to the original specification before cutting real wafers. This preliminary wearing action prevents groove formation in actual wafers while enabling operation resumption, thus resolving the contradiction between productivity and manufacturing precision.
2Loss of time
If the wire diameter is not matched after repair, then operation can be resumed quickly, but grooves are formed in wafers that subsequent processes cannot remove
Solution Approach 1:
The dummy workpiece serves as an intermediary object between the repaired wire and the actual wafers. By wearing the wire on the dummy workpiece first, the system transfers the diameter correction function to this intermediate medium, preventing direct transmission of diameter errors to actual wafers. This allows quick operation resumption while maintaining wafer quality.
3Strength
If a new wire line is supplied after break, then wire strength is restored, but the diameter difference between new and worn wire causes slicing inconsistency
Solution Approach 1:
The patent applies parameter changes by intentionally altering the wire diameter parameter through controlled wearing on a dummy workpiece. The new wire line is worn down to match the original diameter specification, transforming it from a state of excessive diameter to the correct operating parameter. This ensures slicing uniformity while maintaining the restored strength of the new wire.
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 eliminates diameter differences, inhibiting groove formation and improving wafer flatness, reducing the production of low-quality wafers by ensuring consistent wire diameter during resumption of slicing.
Implementation Method 1
slicing the dummy workpiece by supplying and using the new line of the wire with a length larger than the measured wire length
Data Source
AI summary
A method of resuming operation of a wire saw in which slicing of a workpiece is suspended due to a wire break, including processes of: imparting axial reciprocating motion to a wire while supplying a new line of the wire; and slicing the workpiece into wafers by moving the workpiece downwardly to press the workpiece against the reciprocating wire while supplying a slicing slurry to the wire, the method includes: repairing the broken wire after suspending the slicing of the workpiece before resuming the slicing of the workpiece; and preparing for the slicing in that a diameter of the repaired wire at a position at which the workpiece is to be sliced is matched to the diameter of the wire just before occurrence of the wire break. The method can inhibit the formation of grooves in wafers sliced after the resumption and reduce low-quality production wafers.