Work holders – Relatively movable jaws – Specific means for wear – strain – protection – assembly
Reexamination Certificate
2002-04-04
2004-05-18
Bryant, David P. (Department: 3726)
Work holders
Relatively movable jaws
Specific means for wear, strain, protection, assembly
C269S216000, C269S006000, C029S559000, C029S281100, C206S316100
Reexamination Certificate
active
06736386
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to the field of photolithography and, more particularly, to a covered photomask assembly holder and method of using the same.
BACKGROUND OF THE INVENTION
Photomasks, also known as reticles or masks, are used to transfer a pattern representing integrated circuits (ICs) onto a semiconductor wafer. Typically, a photomask is formed from a photomask blank using a standard photolithographic process. Producing a photomask from a photomask blank typically requires a lengthy number of steps including, but not limited to, processing, testing, packaging, and labeling. As a result of this lengthy process, photomasks require frequent handling in a photomask shop, especially when being loaded into a manufacturing tool. Presently, photomasks are handled either by hand or by a mechanical grabbing mechanism commonly known in the industry as a “pick.” Conventional picks contain a handle and two grips that may be manually placed around the perimeter of a photomask.
At least two potential risks exist for damaging a photomask as the photomask is handled and moved around a photomask shop. First, a risk may exist if the photomask comes in contact with an object that scratches a surface of the photomask. While a scratch may be removed during a photomask repair process, each repair process adds time and cost to the manufacturing process. Second, another risk may exist if an uncovered photomask is moved around the photomask shop and small particles of foreign material settle on a surface of the photomask. These particles may damage the photomask or interfere with the production of ICs on a semiconductor wafer.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, disadvantages and problems associated with photomask holders have been substantially reduced or eliminated. In one particular embodiment, a covered photomask holder includes a gripping mechanism that may engage and retain a photomask component within the covered photomask holder. The holder may further include a handle coupled to the gripping mechanism operable to manipulate the gripping mechanism. A protective cover associated with the gripping mechanism may enclose the photomask component while the photomask component is engaged within the photomask holder.
In another embodiment of the present invention, a method for using a photomask holder with a photomask assembly includes placing the photomask holder around the photomask assembly. The method further includes positioning a transparent cover associated with the photomask holder over a surface of the photomask assembly.
Important technical advantages of certain embodiments of the present invention include a covered photomask holder that protects a photomask assembly or a photomask component from being damaged during a photomask or semiconductor manufacturing process. The photomask holder may include a gripping mechanism with a transparent protective cover. The cover may be placed over a patterned surface and possibly below an uncoated surface of a photomask assembly or component. Handling the photomask assembly or component with the protective covers over the photomask assembly or component may prevent scratches or other damage from contact with an object or contamination by any foreign particles during the transfer between manufacturing tools.
Another important technical advantage of the present invention includes a photomask holder that has a locking mechanism for a gripping mechanism that prevents accidental release of a photomask assembly or component from the gripping mechanism. Once the photomask assembly or component is retained within the photomask holder, the locking mechanism may be engaged to prevent the gripping mechanism on the holder from opening. Thus, the photomask assembly or component will be prevented from falling out of the holder due to an accidental release of the gripping mechanism.
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Baker & Botts L.L.P.
Bryant David P.
DuPont Photomasks, Inc.
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