Abstract: A device package includes a die that includes a substrate having first and second surfaces. A sensor is formed at a sensor region of the first surface. A trench extends entirely through the substrate between the first and second surfaces, in which the trench at least partially surrounds the sensor region. An isolation material, formed at the first surface, may extend across the trench A ring structure is coupled to the first surface of the substrate to create a first cavity in which the sensor is contained, the ring structure being laterally displaced away from and surrounding the sensor region and the trench. A molded compound body may abut an outer wall of the ring structure. The molded compound body has a second cavity that is concentric with the first cavity to enable fluid communication between the sensor and an environment external to the device package.

Abstract: A cap wafer bonded to a device wafer by a metal polysilicon germanium material to form a sealed chamber around a semiconductor device is provided. On the cap wafer, a stack of silicon (Si), polycrystalline silicon germanium (SiGe), and polycrystalline germanium (Ge) is formed. This stack of material layers is formed to intentionally have a roughened germanium surface. A metal structure is formed on a second wafer, having an anti-stiction coating layer on the surface of the metal structure. A metal silicon germanium bonding material is formed by placing the metal structure and germanium structure in contact and applying heat and pressure. The roughened germanium layer penetrates the anti-stiction coating layer upon application of the pressure. The germanium that penetrates to the metal is free of interfacial anti-stiction coating and allows for eutectic bond formation upon application of heat.

Abstract: A method for selective etching using a dry film photoresist includes forming an opening through a substrate from a first surface to expose a stop layer at a second surface of the substrate. A material layer is formed over an inner surface of the opening and over the stop layer. The dry film photoresist is applied over the first surface of the substrate and over the opening. A second photoresist is applied on the dry film photoresist. First and second aligned holes are formed in the second photoresist and the dry film photoresist, respectively. The holes are approximately centered over the opening and are smaller in diameter than the opening so that a composite structure of the dry film photoresist and the second photoresist overhangs edges of the opening. The material layer is removed from the stop layer by etching via the first and second holes.