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industry  interview

Improved LED production with

integrated vacuum and abatement

Companies seek to constantly improve their production methods. HBLED manufacturers are faced with many challenges including vacuum and abatement. Mike Czerniak, Product Marketing Manager, Exhaust Gas Management at Edwards discusses the benefits of combustion based abatement technology.

T

he technology used to manufacture high brightness

LEDs (HBLEDs) made from gallium nitride (GaN) has developed rapidly over the last dozen years, and market growth has continued, despite the current economic slowdown. This is a combination of developments in LED technology, the size and contrast benefits LEDs offer in flat panel applications and adesire by both governments and individual consumers around the world to reduce energy consumption due to concerns about global warming.

Current market opportunities driving the expansion in LED production already include laptop computers, as well as liquid crystal displays (LCD) backlighting used in LED TVs and automotive applications. The LED consumer lighting market is also showing growth as LED efficiency has increased to over 100 lumens per watt. For LED technology to become truly competitive in mass- market applications, however, it must still achieve even greater reductions in the initial cost per lumen.

LED manufacturers hope to achieve this cost reduction through economy of scale that comes with high volume production. Increasing production is dependent upon demand. LED manufacturing strategies are focused on addressing the technical aspects of high-volume production, while also minimizing both the capital expenditures and operating costs of production equipment.

As manufacturing processes scale to higher volumes, the relative contribution of variable costs to cost- of-ownership (CoO) often grows as fixed costs are distributed over the increased volume of production. In addition, ramping LED volume production also increases the demands on both vacuum and abatement systems, which must handle higher volumes of production gases or manufacturing by-products, respectively.

The GaN compound semiconductor manufacturing processes used to produce LEDs require large flows of hydrogen and ammonia. Because of the small size of the hydrogen molecule, this gas is difficult to pump, especially in high volumes. At the same time, depending on the abatement technology in use, ammonia can produce solid by- products during the waste removal process that tend to clog the bath, recirculation pump and drain pipes in

36 www.compoundsemiconductor.net April/May 2010

conventional wet scrubbers, requiring them to be cleaned every month or two, during which time the production tools are idle, reducing productivity and increasing tool CoO.

This article discusses the pumping and abatement requirements needed to accommodate the use of hydrogen and ammonia in HBLED production, and highlights an abatement technology that can significantly reduce manufacturing cost of ownership. It also presents a new approach to implementing vacuum and abatement systems within a process tool that can help to further reduce system CoO.

Vacuum Pumping

Pumping hydrogen, regardless of the process involved, presents certain challenges because of the gas’s small molecular size and low viscosity, which is approximately half that of nitrogen. While these characteristics are not an issue when

Figure 1: HBLEDs are replacing

incandescent bulbs in

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