SEMI's HB-LED Standards Committee has approved its first standard, specifying sapphire wafers used in making high-brightness light-emitting diode (HB-LED) devices.
Sapphire wafers are used in producing HB-LED devices for multiple applications: LCD backlights, signage and solid-state lighting. Development of industry standards, in collaboration with the global LED manufacturing supply chain, will help eliminate costs and better enable equipment and process innovation.
Five categories of single-crystal, single-side polished c-axis sapphire wafers are covered by the new HB1 standard:
Flatted 100mm diameter, 650μm thick,
Flatted 150mm diameter, 1,000μm thick,
Flatted 150mm diameter, 1,300μm thick,
Notched 150mm diameter, 1,000μm thick, and
Notched 150mm diameter, 1,300μm thick
SEMI's HB-LED Standards Committee was formed in late 2010, comprised of companies involved in HB-LED devices, sapphire wafers, MOCVD wafer processing, and equipment and materials suppliers. Among its various individual efforts:
-- The HB-LED Wafer Task Force already is seeking refinements to the HB1 standard, including specs for patterned sapphire substrates, double-sided polished wafers, impurities and defects (wafer and bulk), laser marking and identification, and bow and warp measurements. This group also is beginning a second round of experiments with wafer marking to characterize mark survivability, width, and depth; a first round conducted this year "showed promising results" on 100mm and 150mm wafers with front and back-surface marks (i.e., data matrix and OCR) were subjected to various surface modifications (e.g., slicing, grinding, polishing, GaN Ep). For 2013, the group plans to explore core and wafer defect inspection on ultrasonic technology, and conduct surveys on patterned sapphire substrates and double-side polishing.
-- The HB-LED Equipment Automation Task Force plans to reballot a SEMI Draft Document on cassettes for 150mm sapphire substrates, seeking revisions to allow interoperability with existing equipment, taking into account cassette pocket size and spacing. This also will help standardization of load ports and transport systems.
-- Meanwhile, a Software Working Group continues to develop a spec for an automation communication interface between process, automation, and metrology equipment. Another new standard, submitted and approved last October at the SEMI NA Standards Fall 2012 meetings, builds on that automation spec to address materials management and job management.
SEMI also plans to begin experiments and test methods based on a survey deployed last summer about defect vs. inspection techniques, aiming to identify sapphire wafer defects and inspection techniques catering to HB-LED manufacturing.
The wafer, automation, and impurities/defects task forces will be meeting at the Strategies in Light conference Feb. 12-14 in Santa Clara, CA. The NA HB-LEB committee and task forces will meet at the NA Standards Spring 2013 meetings April 1-4 in San Jose.
