Manz showcased its new equipment for wet-chemical processing of crystalline silicon solar cells at SNEC 2012 in Shanghai this May. The IPSG CEI 4800 is designed for chemical edge isolation (CEI) and phosphor silicate glass (PSG) post process removal. The tool is capable of handing 4800 wafers per hour and sold as a bundle with the Manz SpeedPicker for loading and unloading.
Problem
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Wet chemistry isolation is accomplished by the rear side and edges of the wafer being coated in an HF-based chemistry, while the surface emitter layer on the front side is not exposed to the etchant. Wafers are coated with a thin layer of silicon nitride which improves device reliability and serves as an anti-reflection layer. Combining wet chemical processes in short sequential phases provides greater process control and improved throughput for lower production costs.
Solution
The IPSG CEI 4800 is specifically designed to remove the highly doped layer from the backside and the edges of a wafer and thereby produce a chemical edge isolation (CEI). In a second process step the remaining phosphor silicate glass (PSG) layer on the front side of the wafer that was created during the previous diffusion process step, is removed. The newly developed soft sponge roller process concept enables faster inline transportation speeds and ensures higher process stability combined with gentle wafer handling.
Applications
Crystalline silicon wafer PSG removal process.
Platform
IPSG CEI 4800 employs a newly developed soft sponge roller process concept enables faster inline transportation speeds and ensures at the same time higher process stability combined with gentle wafer handling. As the name of the new tool implies, throughput will be high at up to 4800 w/h. The machine will be sold as a bundle with the Manz SpeedPicker for loading and unloading. Manz will produce the IPSG CEI 4800 in its new Suzhou fab in China.
Availability
May 2012 onwards.