PHP connect to hidden share network path

I’m trying to connect to a hidden network drive using ftp_connect, but I’m getting an error message when I try ftp_login.
Is this even possible with PHP?
Thank you!

$ftp_server = 'server02.abc.def.com/c$';
$ftp_user = 'abc/name.user';
$ftp_pass = 'userpwd123';

// set up a connection or die
$ftp = ftp_connect($ftp_server) or die("Couldn't connect to $ftp_server");

// try to login
if (@ftp_login($ftp, $ftp_user, $ftp_pass)) {
echo "Connected as $ftp_user@$ftp_servern";
} else {
 echo "Couldn't connect as $ftp_usern";
}

// close the connection
ftp_close($ftp);