Wafer storage box and method for preventing attachment of dust caused by static electricity on a wafer storage box
AssigneeNEC Corporation
InventorHirotaka Hatada
Life of this patent
Estimating the term…
Abstract
A carrier 2 that holds a wafer 3 is shut off from the outside environment by causing a box 1 and a box plate 4 to come into intimate physical contact by means of a box plate joiner 7. When this is done, a switch 9 of a electricity charger/discharger 5 is set to a first position so as to charge electricity to the box 1 via power supply circuit 10, causing dust within the box 1 to be attached to the inner walls 1a of the box 1 by electrostatic attraction. Thereafter, even if the box plate 4 that was joined to the box 1 is removed from the electricity charger/discharger 5, because the electricity of the box 1 remains, the electrostatic attraction effect persists. Thus, once dust is attracted, it remains attached to the inner walls 1a of the box 1.
Claims6
A box for storing semiconductor wafers in a wafer carrier, the box comprising:
- a cover enclosing a space for receiving a wafer carrier and having an opening at one side for passage of a wafer carrier, an interior wall of said cover being electrically conductive and storing an electrical charge;
- a box plate removably attached to said cover closing said opening;
- and
- a charger/discharger comprising a source of electrical power selectively connected to said interior wall of said cover charging a predetermined voltage to said interior wall when connected and a ground circuit selectively connected to said interior wall discharging an electrical charge stored in said interior wall when connected.
A method of preventing accumulation of dust on semiconductor wafers in a wafer carrier that is in a box for storing the carrier, the method comprising the steps of:
- enclosing a carrier carrying semiconductor wafers with a cover that encloses a space for the carrier, an interior wall of the cover being electrically conductive and storing an electrical charge;
- removably attaching a box plate to the cover to close the opening;
- and
- selectively connecting a source of electrical power to the interior wall of the cover and charging a predetermined voltage to the interior wall, the interior wall storing an electrical charge and electrostatically attracting dust thereto when charged;
- and
- maintaining the electrical charge in the interior wall until a ground circuit is selectively connected to the interior wall discharging the electrical charge stored in the interior wall.
Dependencies are inferred from the claim text.