Browse Prior Art Database

Semiconductor Photomask Inspection Contamination Reduction

IP.com Disclosure Number: IPCOM000061619D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Flanigan, PS: AUTHOR [+2]

Abstract

A technique is shown for reducing semiconductor photomask contamination throughout the entire load/unload and inspection process by causing clean air to flow over the exposed mask surface. During loading and unloading of photomask inspection systems, masks are exposed to submicron particle contamination. State-of-the-art inspection systems have been refined to the point where submicron contamination defects can be detected and true chrome and clear defects may be obscured by these particles and missed by an inspection system. Because inspection systems currently in use operate in a non-stop mode to achieve the required throughput, their power and memory capacity relative to their submicron detection capability is limited. This tends to cause these systems to miss some true defects.

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Semiconductor Photomask Inspection Contamination Reduction

A technique is shown for reducing semiconductor photomask contamination throughout the entire load/unload and inspection process by causing clean air to flow over the exposed mask surface. During loading and unloading of photomask inspection systems, masks are exposed to submicron particle contamination. State-of-the-art inspection systems have been refined to the point where submicron contamination defects can be detected and true chrome and clear defects may be obscured by these particles and missed by an inspection system. Because inspection systems currently in use operate in a non-stop mode to achieve the required throughput, their power and memory capacity relative to their submicron detection capability is limited. This tends to cause these systems to miss some true defects. Because present clean air hoods and glass-cleaning techniques are not able to reduce the submicron particle contamination significantly, an environmental chamber 10, as shown in the figures, may be attached to a photomask inspection system. A photomask case (not shown) can be introduced into the inspection system through a mask loading door 11 which remains open so that a clean air flow from entry point 12 will exit through the mask loading door 11 and purge the mask case of loose contamination. The operator places his gloved arms through holes 13 and 14 and allows the clean air flow to purge the gloves of loose contamination b...