ZMNT is a university research cleanroom and allows a great variety of different materials to be processed including organic materials, III-V-semiconductor and Si-CMOS fabrication. Therefore, in spite of ZMNT’s flexibility, various processes require strict rules of sample handling in order to avoid cross-contamination. To this end, we have introduced three contamination categories, namely A, B, and C. Contamination category A stands for samples that are CMOS compatible, i.e. silicon/SiGe samples without any metal or organic contamination, B include all CMOS samples with CMOS compatible metals (aluminum, tungsten, TiN), and C stand for all other samples.
Handling samples is relatively easy: A sample can only be processed in a tool with a contamination category equal or worse than the sample. For instance, a B-sample can be processed in B- and C-tools but is not allowed to enter any A-tool. After the process the sample takes on the contamination category of the tool, i.e. a B-sample becomes C if processed in a C-tool.
All tools, lab-ware, beakers and tools are labelled with the appropriate contamination category according to the following color coding:
White labels represent contamination category A
Green labels represent contamination category B 
Red labels represent contamination category C