| 摘要 |
A system uses a portable carrier for transporting multiple semiconductor wafers in a substantially particle free environment. A cassette freely received within the carrier for supporting the wafers in spaced generally stacked relationship is delivered to an environmentally clean load lock. A mini-environment defines an interior region adjacent the load lock for the engageable reception of the carrier and sealingly isolates the load lock chamber and the interior of the carrier from the surrounding atmosphere. Transfer mechanisms serve to retrieve the cassette from the carrier and move the carrier into the load lock chamber while maintaining it in a particle free environment. A first transport mechanism within the mini-environment retrieves the cassette from the carrier and moves it into its interior region and a second transport mechanism within the load lock retrieves the cassette from the interior region and moves it into the load lock chamber. To aid in moving the cassette into the interior region, a hood of the mini-environment is movable between lowered and raised positions while maintaining a capillary seal with its upstanding walls. Sensors inform whether a cassette is present in the SMIF box, whether wafers are properly positioned in the cassette, and whether the cassette is properly gripped as it is being moved into the interior region. Laminar flow air is continually directed through the interior region of the mini-environment and filtered to remove foreign particles from the wafers being supported in the cassette. |
