07/11 PSS Sapphire Wafer - Wet vs. Dry Etching


The U.S. Department of Energy is expected to release a report stating that in order to compete effectively with the fluorescent lighting market, solid-state lighting manufacturers need to cut the cost per lumen (currently at $18/klm) by 8x to $2.20/klm by 2015

Gaining efficiencies during the manufacturing process is a key method to drive down costs. Larger-diameter sapphire wafers hold the promise of making the manufacturing process significantly more efficient, but they also present challenges to fabricators.

Patterned Sapphire Substrates (PSS) serve a dual-purpose role in the LED industry. On the wafer supplier side, they are money-makers. PSS wafers represent higher gross margins than traditionally polished sapphire wafers. On the product development side, PSS-based LEDs are more efficient, more effective light sources.

Dry etching is currently the most common method for producing PSS wafers. At this point, the techniques and technology for dry etching, including the inductively coupled plasma (ICP) variant of dry etching are commonplace. Though dry etching is slow and maintains limited throughput.  

In comparison, the high-temperature wet etching process provides the dual advantages of being extremely fast and comparatively much cheaper than dry etching. Read More...