OEM Group of Phoenix, AZ, USA (which supplies new and re-manufactured semiconductor capital equipment and upgrades focused on emerging markets) says that a leading LED maker has placed a repeat order for an AGHeatpulse RTP (rapid thermal process) system, to be used for annealing gallium nitride (GaN) films deposited on 150mm sapphire substrates. OEM Group says that the repeat order again validates the AGHeatpulse RTP system's demonstrated capabilities meeting the exacting thermal requirements of new LED manufacturing technologies, and supports the LED industry's move from batch processing of smaller-diameter sapphire substrates to single-wafer processing of 150mm sapphire substrates.
Currently, over 75% of all LEDs are manufactured using GaN-on-sapphire technology. The deposited GaN layer benefits from a thermal anneal process to improve the crystalline structure of the GaN layer. Traditionally, this has been performed in small furnaces or manual-load RTP systems.
"LED manufacturers have begun to leverage the cost efficiencies of large-diameter substrates," comments sapphire substrate maker Rubicon Technologies. "LED manufacturers have been making progress in migrating to 6-inch wafers," he adds. "During the production process, the use of, say, 2-inch wafers, means more wasted space between wafers and more edge loss. So 6-inch enables a more efficient production process, resulting in a lower LED cost."
However, lingering technology challenges have created some limitations for the mass adoption of large-diameter LED substrates.
OEM Group says that, with its emphasis on developing enabling technologies for new markets, it optimized the AGHeatpulse RTP system to meet LED fabrication device performance, reliability, and product yield requirements, and to meet LED manufacturing cost targets. For the GaN anneal process, the firm's development team ported the proven capabilities of automated RTP systems from silicon device applications to high-volume manufacturing of LEDs on 150mm sapphire substrates. The repeat order from a leading LED customer demonstrates the value of OEM Group's emphasis on development and continuous innovation, the firm adds.
Originally manufactured by AG Associates and now owned and manufactured by OEM Group, the AGHeatpulse RTP system has demonstrated proven ability to meet the technology requirements for the latest LED devices. Specific benefits of the Heatpulse system that are important for the manufacture of LEDs include:
control and repeatability of the thermal ramp-up and steady-state temperature; uniform temperature across the substrate with high run-to-run repeatability; fully automated substrate handling using a unique susceptor auto-loader; and advanced data-log reporting and host control capability.
