Cleanliness Specification and Post Processes

Although cleanliness parameters are not common in post processes, the following general measures, based on the total residual contamination in mg/m2, may be used.

  • Cleaning   < 500 mg total soil/m2
  • Precision cleaning  < 50 mg total soil/m2
  • Critical cleaning  < 5mg total soil/m2

The cleaning criteria are often based on the performance requirements in the post process period, such as the adherence of paint coatings or use in the electronics industry. More recently, the automobile industry set specific requirements for cleaned surfaces with special emphasis on particles (VDA 19).