Diamond Wire Wear Inspection
The Resonance Vibrations (RV) method was developed for non-destructive real-time inspection of Diamond Wire (DW) quality (pending patent). Theoretical model of RV in moving strings was developed. The in-line RV-DW sensor induces small vibrations in elastic DW segments during the wire motion in a wafer cutting tool and measures its resonance characteristics to assess wire quality and DW wearing stage. Core elements of the RV-DW sensor include a non-contact actuator and probe. The RV data acquisition and analyses are performed within tens of milliseconds, matching the speed of the modern wafering process. The sensor is computer controlled with Windows based software and convenient Graphical User Interface.
RV vs. Optical
Wafer producers are exploring a high resolution optical imaging to assess DW quality by detecting loss of material and tracking the DW wearing stage.
Optical method disadvantages:
- Only surface diagnostics of the wire components, while the DW wearing is also affected by degraded sub-surface layers (Ni, Cu.)
- Algorithm for real-time DW optical inspection generates high uncertainties caused by irregularities in the diamond particles.
- Wafering process creates chemical residues that requires frequent maintenance of the optical hardware.
- Ensures inspection of the DW bulk and surface properties (both diamond particle loss and sub-surface metallization) during wafering.
- Reduces scrap material by eliminating DW breakage which leads to yield reduction and product cost increase.
RV Sensor Specifications
- Minimum diamond wire diameter - 120 microns
- Maximum DW speed - 20 meters per second
- Maximum temperature – 60C
- Accuracy of diamond wire wear – 10%