Digital defect tracking in sapphire processing: Case study on the micro-LED chain

Scientific Visual is proud to present a case study on the impact of sapphire material defects on LED wafering.

An automated crystal scanner recorded defects in sapphire boules as they passed through consecutive production steps: raw crystals (boules) ➜ cores ➜ EPI-ready wafers.

In parallel, the defectiveness was assessed by experts using manual methods.

The experiment design allowed individual defects to be traced backwards through all processing steps.

By tracing the defects from start to end, the authors were able to

a) correlate defects critically impacting polished wafers with those identified by the TotalScan™ scanner in raw sapphire crystals

b) compare the results of automated and manual quality control in sapphire

c) demonstrate the increase in yield through “smart wafering” – optimal positioning of sapphire cores in a wafering system.

The paper has been published in IEEE Xplore as a proceedings of the China Semiconductor Technology International Conference 2022 (CSTIC – Semicon).

Download the paper