BOC aims to increase the brightness of LEDs

11/01/2001

Meg Villeneuve

Wilmington, MA—BOC Edwards has developed an ammonia gas production system that removes impurities for use in the manufacturing of light emitting diodes (LEDs).

High purity ammonia gas has applications in the semiconductor, LED, and flat panel display markets where low levels of metallic impurities and moisture are required for processing. "By removing the impurities, LED manufacturers will be able to improve the photo luminescence of LED, or make it brighter," says Rob Limouze of BOC.

The system uses a vapor phase transfer operation to remove metallic impurities and oil, which are common contaminants in raw anhydrous ammonia streams. Moisture is removed utilizing a chemical/mechanical dryer unit, according to BOC.

The system is external to the fab and can annually produce up to 150 tons of Grade 6.0+ liquid ammonia with a moisture content of less than 0.3 ppm.

BOC hopes to have its first unit in production in Asia by 1H02. The ultra-high purity ammonia gas production system is a redesign of an existing unit for BOC. "The design is an improvement on existing units that require frequent downtime for cleaning and regeneration due to unpredictable levels of impurities in the raw ammonia feed stream," the company says.