27 September 2011

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

GT Advanced Technologies Inc of Merrimack, NH, USA (a provider of polysilicon production technology as well as sapphire and silicon crystalline growth systems and materials for the solar, LED and other specialty markets) has released a case study ‘Yields Matter: The Impact of Sapphire Material Quality on the LED Wafering Process’ that 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’s Advanced Sapphire Furnace (ASF) grown sapphire material delivers the highest wafer yields, the firm claims.

“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,” says Cheryl Diuguid, VP & general manager Sapphire Material and Equipment. “Wafer yields are especially critical to wafer manufacturers as they directly impact their economics,” she adds. “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. GT says that, to obtain unbiased data, it worked through an independent 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.

The 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 HB-LED value chain.

The firm is presenting the findings of the study in booth M-78 at the LED Japan Conference & Expo/Strategies in Light trade show in Yokohama (28-30 September). The paper will also be available on the company’s web site.

Tags: GT Advanced Technologies Sapphire crystallization furnaces

Visit: www.gtat.com