Continental Automotive Systems Corporation

Motorola Corporation

Temic Automotive of North America, Inc.

Xiaoyi Ding

Jeffrey J Frye

John Patrick Schuster

James Nowicki

Gregory A Miller

Jen-Huang Albert Chiou

Shiuh-Hui Steven Chen

Walter S Czarnocki

Carl A Ross

James Norwicki

A pressure sensor device which uses appropriate passivation materials/patterns to make the device more robust and resistant to a hot and humid environment. The pressure sensor device uses moisture resistant passivation material(s) covering exposed glass areas, including sidewalls, and bonding interfaces to avoid the glass and bonding interfaces absorbing and reacting with moisture, thus maintaining the integrity of the device output after exposure in a humid/hot environment. These passivation materials/patterns used for the MEMS devices described may be applied to any MEMS based sensors and actuators using glass as one type of material for fabrication. The pressure sensor devices may be front side absolute pressure sensors, differential pressure sensors, or back side absolute pressure sensors.

Humidity resistant sensors and methods of making same

A sensor device is constructed to maintain a high glass strength to avoid the glass failure at low burst pressure, resulting from the sawing defects located in the critical high stress area of the glass pedestal as one of the materials used for construction of the sensor. This is achieved by forming polished recess structures in the critical high stress areas of the sawing street area. The sensor device is also constructed to have a robust bonding with the die attach material by creating a plurality of micro-posts on the mounting surface of the glass pedestal.

Embedded structures for high glass strength and robust packaging

A pressure sensor includes a top cap with a recess formed in an end of the top cap and a cavity formed in the end of the top cap to communicate with the recess. The cavity extends further axially into the top cap than the recess thereby having depth greater than a depth of the recess. Outer edges of the recess extend laterally outward beyond outer edges of the cavity thereby defining a bonding boundary. A silicon substrate has a sensing circuit on a top side thereof. The top cap is bonded to the top side of the silicon substrate in a range from the outer edges of the top cap to the bonding boundary. The recess and the cavity of the top cap face the top side of the silicon substrate and form a reference vacuum cavity. When pressure is exerted on a backside of the substrate, a portion of the substrate is constructed and arranged to deflect.

Absolute pressure sensor with improved cap bonding boundary

In a MEMS PRT having a diaphragm that is located offset from the center of the die, thermally-induced thermal noise in the output of a Wheatstone bridge circuit is reduced by locating the Wheatstone bridge circuit away from the largest area of the die and supporting pedestal.

Piezoresistive transducer with low thermal noise

A pressure sensor includes a pressure sensing element having a diaphragm, a cavity, and bridge circuitry connected to the diaphragm. A top surface is formed as part of the pressure sensing element such that at least a portion of the top surface is part of the diaphragm, and the plurality of piezoresistors are located on the top surface. A cap is bonded to the top surface through the use of a plurality of layers. One of the layers is a silicon dioxide layer, another layer is a silicon nitride layer, another layer is an oxide layer, and another of the layers is a polysilicon layer. The plurality of layers provides proper bonding between the cap and the top surface of the pressure sensing element.

Cap side bonding structure for backside absolute pressure sensors

Ultra-thin semiconductor devices, including piezoresistive sensing elements can be formed in a wafer stack that facilitates handling many thin device dice at a wafer level. Three embodiments are provided to form the thin dice in a wafer stack using three different fabrication techniques that include anodic bonding, adhesive bonding and fusion bonding. A trench is etched around each thin die to separate the thin die from others in the wafer stack. A tether layer, also known as a tether, is used to hold thin dice or dice in a wafer stack. Such as wafer stack holds many thin dice together at a wafer level for handling and enables easier die picking in packaging processes.

Thin semiconductor device having embedded die support and methods of making the same

Ultra-thin semiconductor devices, including piezo-resistive sensing elements can be formed a wafer stack that facilitates handling many thin device dice at a wafer level. Three embodiments are provided to form the thin dice in a wafer stack using three different fabrication techniques that include anodic bonding, adhesive bonding and fusion bonding. A trench is etched around each thin die to separate the thin die from others in the wafer stack. A tether layer, also known as a tether, is used to hold thin dice or dice in a wafer stack. Such as wafer stack holds many thin dice together at a wafer level for handling and enables easier die picking in packaging processes.

A semiconductor die is attached to a substrate by a glass frit layer. Gas that might be trapped between the die and the glass frit layer during firing of the glass frit can escape through passages that are formed against the bottom surface of the die by topographies that extend away from and which are substantially orthogonal to the bottom of the die.

Thin semiconductor die package

MEMS pressure sensing elements, the fabrication methods of the sensing elements, and the packaging methods using the new sensing elements are introduced to provide a way for a harsh media absolute pressure sensing and eliminating the negative effects caused by the gel used in the prior art. The invention uses vertical conductive vias to electrically connect the enclosed circuit to the outside, and uses a fusion bond method to attach a cap with the embedded conductive vias over a device die having a circuit for example a piezoresistive Wheatstone bridge to sense pressure. New packaging methods comprise a) a two-pocket housing structure and using a surface mounting method to attach a new sensing element into one pocket by a ball grid array (BGA), and b) a single pocket structure and using conventional die attach and wire bonding. Both methods can be used for harsh media pressure sensing but without the negative effects caused by the gel in prior art.

Pressure sensor for harsh media sensing and flexible packaging

A microdevice () having a hermetically sealed cavity () to house a microstructure (). The microdevice () comprises a substrate (), a cap (), an isolation layer (), at least one conductive island (), and an isolation trench (). The substrate () has a top side () with a plurality of conductive traces () formed thereon. The conductive traces () provide electrical connection to the microstructure (). The cap () has a base portion () and a sidewall (). The sidewall () extends outwardly from the base portion () to define a recess () in the cap (). The isolation layer () is attached between the sidewall () of the cap () and the plurality of conductive traces (). The conductive island () is attached to at least one of the plurality of conductive traces (). The isolation trench () is positioned between the cap () and the conductive island () and may be unfilled or at least partially filled with an electrically isolating material. There is also a method of making the same microdevice.

Wafer-level sealed microdevice having trench isolation and methods for making the same

A microdevice that comprises a device microstructure () and vent channel () in a wafer () that is sandwiched between a substrate () and a cap (). The cap () and substrate () have recesses () around the microstructure () to define a cavity. A vent () is connected to the vent channel () and subsequently to the cavity. The vent () is used to evacuate and seal the microstructure () in the cavity. A getter layer () can be used to maintain the cavity vacuum. An electrical connection can be provided through the vent (), vent channel () and cavity to the getter () to electrically ground the getter layer ().

Hermetically sealed microdevice with getter shield

A microdevice () having a hermetically sealed cavity () to house a microstructure (). The microdevice () comprises a substrate (), a cap (), an isolation layer (), at least one conductive island (), and an isolation trench (). The substrate () has a top side () with a plurality of conductive traces () formed thereon. The conductive traces () provide electrical connection to the microstructure (). The cap () has a base portion () and a sidewall (). The sidewall () extends outwardly from the base portion () to define a recess () in the cap (). The isolation layer () is attached between the sidewall () of the cap () and the plurality of conductive traces (). The conductive island () is attached to at least one of the plurality of conductive traces (). The isolation trench () is positioned between the cap () and the conductive island () and may be unfilled or at least partially filled with an electrically isolating material. There is also a method of making the same microdevice. sidewall () extends outwardly from the base portion () to define a recess () in the cap (). The isolation layer () is attached between the sidewall () of the cap () and the plurality of conductive traces (). The conductive island () is attached to at least one of the plurality of conductive traces (). The isolation trench () is positioned between the cap () and the conductive island () and may be unfilled or at least partially filled with an electrically isolating material. There is also a method of making the same microdevice.

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Xiaoyi Ding