| 摘要 |
In a wheeled carrier for transporting wafers of semiconductor material during processing, the wheels are non-rotatably mounted on axles and each pair of wheels has either central recesses on their outer faces accepting sub shafts in allignment with the axle, or central stub shafts projecting into recesses in a support structure, for rotation of the wheel/axle assemblies about opposing pairs of stub shafts. The stub shafts, and optionally the inner surfaces of the recesses, are highly polished and shaped to minimize resistance to motion caused by friction between the contact surfaces of the recess and stub shafts since the carrier is made of refractory material such as quartz having a high coefficient of resistance. To minimize accumulation of contaminating particles in the recesses in the wheels, passages are provided through the wheels between the recess and the inner face of each wheel for easier access to the bottom of the recesses.
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