To meet cleanliness specifications, the first thought is frequently “Build it in a Cleanroom.” However, not every critical component need be processed in a large, tightly specified cleanroom by gowned personnel.
Sometimes mini-environments provide a superior and cost-effective option. We are expanding the concept of the mini-environment from that often used in microelectronics to encompass any small, atmosphere-controlled enclosure that allows processing without contaminating the product or the external environment.
While most processing is done in large air and humidity-controlled cleanrooms, critical processing of wafers is frequently performed in smaller self-contained enclosures that contain the wafers and robotically-operated processing tools. The super-critical cleanliness environments required for processing or transport are confined to small volumes, providing cleanliness levels unachievable even with head-to-foot gowning of personnel.
A mini-environment approach to cleaning critical components can be employed even when required cleanliness levels are not so severe as for semiconductor wafer processing. Frequently, by using a mini-environment, a process can be performed in an area built to a lower cleanliness standard. This saves costs of building, facility maintenance, and gowning. Another use for mini-environments is for multiple applications within the same workspace.
Therefore, when faced with cleaning specifications for a new product line, sometimes think small instead of big. A mini-environment may provide lower cost, higher performance, and better protection for both the product and the worker. Consider whether or not mini-environments have a place in your process flow, in and out of the cleanroom.
From: “Controlled Mini-Environments”