Another approach that solves the overlap problem:

++$seen{lc($_)} for split /\s+/, $zipFile;
if ($seen{this} && $seen{$that}) {
    ....
}
[download]

gives the same results as

if ($zipFile =~ /\bthis\b/i && $zipFile =~ /\bthat\b/i) {
    ....
}
[download]