GT Advanced Technologies releases case study on impact of sapphire material quality on LED wafering process

MERRIMACK, USA: GT Advanced Technologies Inc. announced the release of a case study “Yields Matter: The Impact of Sapphire Material Quality on the LED Wafering Process.”

The paper details the findings of a blind material study on the effects of sapphire material quality on the epi-ready wafer manufacturing process for High Brightness (HB) LEDs. The study demonstrates that sapphire material quality has a direct impact on LED wafer yields and that, of the materials from four suppliers that were tested, GT Advanced Sapphire Furnace (ASFTM) grown sapphire material delivers the highest wafer yields.

“GT has been supplying sapphire to the LED industry for over 12 years. We initiated this evaluation project in order to validate the positive observations that we have heard from materials customers on the superior quality of ASF grown sapphire material and its favorable impact on wafer yields,” said Cheryl Diuguid, VP and GM Sapphire Material and Equipment. “Wafer yields are especially critical to wafer manufacturers as they directly impact their economics. The data illustrates that there are differences in wafer yields for various sapphire material sources and that GT’s ASF material performed the best.”

The study evaluated 25 core samples from GT ASF and three other sapphire suppliers. To obtain unbiased data, GT worked through an independent, leading wafer manufacturer and provided blind, unmarked material sources. Data was collected on key wafering parameters that drive yield and cost including wafer geometry (surface roughness or Ra, total thickness variation or TTV, warp and bow) and the rate of wafer rejections.

This wafering analysis is part of a larger comprehensive material characterization project initiated by GT to study the effects of sapphire material properties on the entire manufacturing processes in the High Brightness (HB) LED value chain.