US Patent 7487681 Pressure sensor adjustment using backside mask

Methods and apparatus for an absolute or gauge pressure sensor having a backside cavity with a substantially vertical interior sidewall. The backside cavity is formed using a DRIE etch or other MEMS micro-machining technique. The backside cavity has an opening that is cross shaped, where the dimensions of the cross may be varied to adjust pressure sensor sensitivity. The cross may have one or more rounded corners to reduce peak stress, for example, the interior corners may be rounded. A sensing conductor may be routed over one or more corners including the interior corners to detect breakage.