A MEMS sensor includes a silicon substrate that has a first surface and a second surface on a side opposite to the first surface and that has a cavity in the first surface, a silicon diaphragm that has a first surface and a second surface on aside opposite to the first surface and in which the second surface is joined directly to the first surface of the silicon substrate, and a piezoresistance formed at the first surface of the silicon diaphragm, and, in the MEMS sensor, a plane orientation of the first surface of the silicon substrate and a plane orientation of the first surface of the silicon diaphragm differ from each other.

A method including fusion bonding a handle wafer to a first side of a device wafer. The method further includes depositing a hardmask on a second side of the device wafer, wherein the second side is planar. An etch stop layer is deposited over the hardmask and an exposed portion of the second side of the device wafer. A dielectric layer is formed over the etch stop layer. A via is formed within the dielectric layer. The via is filled with conductive material. A eutectic bond layer is formed over the conductive material. Portions of the dielectric layer uncovered by the eutectic bond layer is etched to expose the etch stop layer. The exposed portions of the etch stop layer is etched. A micro-electro-mechanical system (MEMS) device pattern is etched into the device wafer.

A semiconductor layer having an opening and a MEMS resonator formed in the opening is disposed between first and second substrates to encapsulate the MEMS resonator. An electrical contact that extends from the opening to an exterior of the MEMS device is formed at least in part within the semiconductor layer and at least in part within the first substrate.

Provided is a synthetic quartz glass substrate for use in a microfluidic device to which bonding by optical contact can be applied in manufacturing a microfluidic device, and which has high adhesion in a bonded interface and does not cause defects such as non-bonding and breakage of the substrate and a defect in which air bubbles are sandwiched at the bonded interface.

A synthetic quartz glass substrate for use in a microfluidic device, wherein a maximum value of a cyclic average power spectral density at a spatial frequency of 0.4 mm.sup.−1 or more and 100 mm.sup.−1 or less is 5.0×10.sup.15 nm.sup.4 or less, the maximum value being obtained by measuring any given region of 6.0 mm×6.0 mm on a surface of the synthetic quartz glass substrate with a white interferometer.

Structures and formation methods of a semiconductor device structure are provided. A semiconductor device structure includes a semiconductor substrate including a cavity and a movable feature in the cavity. The semiconductor device structure also includes a cap substrate bonded to the semiconductor substrate to seal the cavity. There is an interface between the cap substrate and the semiconductor substrate. The semiconductor device structure further includes a sealing feature embedded in the semiconductor substrate and surrounding the cavity. The sealing feature extends across the interface and penetrates through the cap substrate.

The present disclosure provides one embodiment of an integrated microphone structure. The integrated microphone structure includes a first silicon substrate patterned as a first plate. A silicon oxide layer formed on one side of the first silicon substrate. A second silicon substrate bonded to the first substrate through the silicon oxide layer such that the silicon oxide layer is sandwiched between the first and second silicon substrates. A diaphragm secured on the silicon oxide layer and disposed between the first and second silicon substrates such that the first plate and the diaphragm are configured to form a capacitive microphone.

A package structure includes a device chip, a MEMS die, a cap structure, and an eutectic bonding layer. The MEMS die is over the device chip and includes a substrate having a plurality of cavities and a conductive layer covering a bottom surface and sidewalls of each of the cavities. The cap structure is coupled to the MEMS die, and the cap structure includes a base substrate having at least one seal ring located in the cavities and a bonding layer covering a first surface and at least part of sidewalls of the seal ring. The first surface of the seal ring faces the MEMS die. The eutectic bonding layer is located between the conductive layer and the bonding layer in the cavities. In addition, a method of manufacturing the package structure is provided.

A method of fabricating a semiconductor substrate includes the following steps. A first wafer is provided and a first surface of the first wafer is etched to form a plurality of cavities. A second wafer is formed on the first surface, where forming the second wafer includes the following steps: providing a core substrate; forming a first insulating layer on the core substrate; and depositing a polysilicon layer on the first insulating layer and the core substrate. In addition, the polysilicon layer is bonded with the first wafer to cover the cavities, where the polysilicon layer is disposed between the first insulating layer and the first wafer. In addition, a semiconductor substrate and MEMS devices using the semiconductor substrate are also provided.

Microelectromechanical (MEMS) devices and associated methods are disclosed. Piezoelectric MEMS transducers (PMUTs) suitable for integration with complementary metal oxide semiconductor (CMOS) integrated circuit (IC), as well as PMUT arrays having high fill factor for fingerprint sensing, are described.

Micromachined ultrasonic transducers integrated with complementary metal oxide semiconductor (CMOS) substrates are described, as well as methods of fabricating such devices. Fabrication may involve two separate wafer bonding steps. Wafer bonding may be used to fabricate sealed cavities in a substrate. Wafer bonding may also be used to bond the substrate to another substrate, such as a CMOS wafer. At least the second wafer bonding may be performed at a low temperature.