Projection mask storage and carrier system
AssigneeThe Perkin-Elmer Corporation
InventorTheodore Watkin
Life of this patent
Estimating the term…
Abstract
There is disclosed a system for storing a projection mask of the type used for printing integrated circuit patterns on silicon wafers. A special cassette package permits the mask to be stored in a clean sealed environment. A delivery system transports the sealed cassette into an optical projection instrument wherein the cassette is opened and the mask advanced to the projection stage. After projection, the mask is returned and automatically sealed into the cassette. The cassette may be evacuated or, alternatively, filled with a clean gas. The mask sealed in the cassette can then be stored until its use is again required.
Claims22
A system for protecting a projection mask used in a projection machine which comprises:
- a mask carrier in the form of a hollow frame and means for selectively securing a mask therein;
- first and second covers engageable with opposite sides of said carrier frame, thereby forming a cassette enclosing said mask therein;
- means in said projection machine for receiving said cassette;
- means associated with said receiving means for engaging said first and second covers and removing them from, and replacing them into, engagement with said carrier frame;
- and
- means for advancing said carrier and its contained mask to a projection location and returning them to said receiving means, whereby said cover engaging means may replace said covers on said carrier in preparation for removal from said machine.
A system for protecting a projection mask used in a projection machine which comprises:
- a mask carrier in the form of a hollow frame and means for selectively securing a mask therein;
- first and second covers engageable with opposite sides of said carrier frame in substantially gas-tight relationship thereto, thereby forming a cassette enclosing said mask therein;
- a gas passage defined by at least one of said covers for transferring gas between the exterior and interior of said cassette;
- a normally closed valve in said gas passage;
- means in said projection machine for receiving said cassette and opening said valve;
- means for flowing gas through the opened valve;
- means associated with said receiving means for engaging said first and second covers and removing them from, and replacing them into, engagement with said carrier frame;
- and
- means for advancing said carrier and its contained mask to a projection location and returning them to said receiving means, whereby said cover engaging means may replace said covers on said carrier in preparation for removal from said machine.
A cassette for protecting a projection mask which comprises:
- a mask carrier in the form of a hollow frame and means for selectively securing a mask therein;
- first and second covers engageable with opposite sides of said carrier frame in substantially gas-tight relationship thereto to enclose said mask therebetween;
- a gas passage defined by at least one of said covers for transferring gas between the exterior and interior of said cassette;
- and
- a normally closed valve in said gas passage.
The method of protecting a projection mask and automatically positioning said mask within a projection machine which comprises:
- providing a mask carrier in the form of a hollow frame;
- securing said mask within said carrier;
- applying first and second covers to said carrier on opposite sides of said mask;
- evacuating the interior of the covered carrier to secure said covers and provide a protective atmosphere for said mask;
- placing the evacuated covered carrier in a receiving area within said machine;
- releasing the vacuum within said covered carrier;
- separating said first and second covers from said carrier;
- advancing said carrier and mask to an exposure location within said machine;
- retracing said carrier and mask to said receiving area;
- replacing said first and second covers on said carrier;
- reevacuating the interior of the covered carrier;
- and
- removing the evacuated covered carrier from said receiving area.
Dependencies are inferred from the claim text.