Appeal No. 2004-1123
Application No. 09/933,503
Like the examiner, we view the patents to Baseman, Roberson,
Parikh and Brooks applied in the rejection before us on appeal as
also addressing contamination problems, similar to those noted by
appellants, in SMIF pods and other wafer storage containers. In
that regard, Brooks (col. 1) mentions the need for removing
contaminants such as "moisture, oxygen, ion contaminants and the
like" from a wafer storage container interior and maintaining the
interior contaminant free for an extended period of time. Brooks
expressly notes that, due to the ever increasing sensitivity of
semiconductor wafers, the presence of even infinitesimal amounts
of contaminants is a drawback to quality production and the
elimination of rejects. In Brooks, column 1, lines 42-49, it is
indicated that one known form of protection is to use a
desiccant, such as Silica Gel, prepackaged in a vapor
transmission type material which is placed within the plastic
wafer storage container prior to sealing thereof. The desiccant
is said to act to absorb atmospheric contaminants such as
moisture vapor and oxygen during packaging and storage of wafers.
However, Brooks further notes that desiccants have a relatively
limited shelf-life and therefore may eventually require time
consuming and expensive repackaging and replacement. Thus,
Brooks proposes an alternative purging method and apparatus which
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