Defect Height in Thin Glas Laminates

Challenge

OLED productions trend is to manufacture thin glas laminates from roll to roll. AOI for defect inspection is challenged by resolution requirements <10µm and the width of the substrate of min 300 mm. Most challenge is to determine the vertical position of the defect in the laminated stack, where the thickness of one layer is in the range of 30µm!

Feasibility

aSpect evaluated the vertical resolution to measure defects in thin glas laminates. The defects are sensed using dark field illumination. The vertical resolution is measured by stereoscopic view, which is projected with mirrors to one camera.

Result

The vertical position is measured in the lab by moving the thin glas with a scratch in vertical direction. Positioning stage has accuracy of 0.5 µm. Measured vertical position vs. stage position is depicted below.

Next Steps

Results look very promising! Setup for 300 mm tape with resolution <10 µm is a battle in invest for hardware (camera, illumination, processing). We are looking forward to your request .