Eco-Snow Systems, an affiliate of The Linde Group, has developed automated cleaning technology for the Micro Electrical Mechanical Systems (MEMS) industry that utilises CO2 and helps reduce defect rates and increase device reliability.

Eco-Snow Systems is considered to be the leading supplier of automated, carbon dioxide (CO2)-based wafer cleaning tools and processes to the semiconductor industry.

Two major US MEMS manufacturers have installed the Eco-Snow VersaClean™ system for packaging component cleaning and the Eco-Snow WaferClean™ system for released device level cleaning prior to wafer dicing.

“Our customers have seen the effectiveness of the Eco-Snow automated CO2 snow cleaning technology in removing contaminants on MEMS wafer caps, released devices and packaging components,” said Joe Clark, General Manager of Eco-Snow Systems.

An essential process
Cleaning is an essential process for MEMS applications in order to prevent device failure due to foreign material. Small particles located on MEMS devices, or within their protective packaging, are significant causes of device rejection.

“The Eco-Snow tools are a particularly good fit for the MEMS accelerometer market, since we can perform gentle to aggressive cleaning on wafers or in packaging. The all-dry process has a unique ability to remove particles from the released cantilever beams of accelerometers without removing the anti-sticktion lubricant or corrupting the device,” Clark said.

Those in the industry would seem to agree with the view that such CO2-based cleaning techniques are fundamental for effective MEMS production processes.

Marc Papageorge, MEMS consultant and founder of Pleasanton, California-based Semiconductor Outsourcing Solutions, affirmed, “The Eco-Snow tools provide an excellent solution for backend-assembly MEMS providers to remove contaminants that otherwise would have ended up sealed in the package.”

As a dry solid, CO2 snow works by transferring momentum from the snow particle to the contaminant material. The Eco-Snow technology is easy to maintain, reliable, economical and simple to integrate into front or back end production lines.

Compared with traditional wet cleaning, the Eco-Snow process is cost effective and minimises environmental impact, as CO2 has a much lower global warming potential than the solvent cleaning alternatives.