Gold savings can pay back equipment cost within a year?
ClassOne Technology, manufacturer of budget-friendly wet processing equipment, is reporting significant savings in the plating of gold in ≤200 mm applications using its Solstice systems. The savings come from elimination of gold waste, faster and simpler processing, and Solstice-enabled techniques that can substantially reduce gold usage.
"Many users have been spending millions of dollars on gold each year," said Byron Exarcos, President of ClassOne Group. "It's a major issue, especially in emerging markets such as lasers, LEDs, RF and MEMS which often require gold layers as thick as 3 to 35 microns. "That's why they're becoming keenly interested in Solstice to cut their gold spending."
"One fundamental advantage of Solstice electroplating is its elimination of gold waste," explained Kevin Witt, President of ClassOne Technology. "Previously used CVD and PVD methods deposited gold not just on the wafer but also on the entire chamber interior. That "˜oversprayed' gold was difficult to remove and inefficient to reclaim "” which led to a considerable net loss of gold. By contrast, Solstice deposits only on the wafer, so there's no gold waste, and no need for cleaning or gold reclamation efforts."
Witt pointed out that Solstice economies also come from its higher gold deposition speed. Plating at 150 to 300 nm/min, it is roughly ten times faster than CVD and PVD methods. In addition, Solstice starts processing immediately, not requiring an hour or more for pump-down as vacuum-based tools do. All of this translates to additional savings, from higher throughput and more cost-efficient production.
The 8-chamber design of the Solstice S8 enables it to replace a solid gold layer with a multi-metal stack "” and reduce gold usage substantially the company says.
For example, a feature that previously required a 5µm layer of solid gold can now be replaced with a "sandwich" of 0.25 µm Au,1 µm Ni, 2.5 µm Cu, another 1 µm Ni, topped with 0.25 µm Au "” to achieve equivalent functionality while reducing gold usage by a factor of ten! And Solstice's multi-chamber design enables it to deposit all five layers in a single cycle; so no additional process steps or time are required to gain very significant cost savings.
ClassOne say that over a year, total gold savings can be significant. For example, in the case cited above, if the solid gold 5 µm layer covers 50 percent of a 150 mm wafer area, and if the fab is running 1500 wafers per week through a metal lift-off process and gold costs $1200 per troy ounce "” even if all oversprayed gold were recovered, the user's annual gold expenditure would be roughly $2,150,000. However, if the special Solstice multi-metal layering technique were used, the total metal cost (for Au, Ni and Cu combined) would be reduced to approximately $108,000. This would yield an annual savings of over $2,042,000, which would more than pay back the cost of a Solstice.
The Solstice S8 provides eight modular chamber positions that can be used for plating a wide range of metals as well as performing additional processes. Solstice tools are available in three different models for production and development, and they serve many cost-sensitive emerging markets that use 200 mm and smaller wafers.
