Silicon Microstructures, Inc.

Ic Sensors Inc.

Transensory Devices, Inc.

Tactile Perceptions, Inc.

Smi Corporation

Hybond, Inc.

Wystron, Inc.

Transensory Device, Inc.

Henry V Allen

Stephen C Terry

James W Knutti

Kurt Edward Petersen

Diederik W De Bruin

Carl Raymond Kowalski

Abhijeet Sathe

John H Jerman

Lloyd D Ingle

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.

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. One embodiment provides for a diaphragm having a boss manufactured using a two step process that results in a boss thickness that is independent of the thickness of the starting material. Another provides for various shapes to the backside cavity that reduces the likelihood of crystalline fractures while focusing stress on piezoresistive sensing elements. Another provides for a sensitivity adjustment by thinning the insulating and silicon layers that form the sensor diaphragm. A pressure sensor according to the present invention may incorporate one or more of these, or may incorporate other elements discussed herein.

Extremely low cost pressure sensor realized using deep reactive ion etching

Glass with metal deposited on it in a pattern which is slightly larger than the cavity area of the corresponding silicon wafer. The metal layer has a thickness such that the glass can deform sufficiently to allow bonding of the glass to the silicon. The metal is then compressively bonded to the silicon in a rim area around the edge of the cavity. The metal provides a barrier to helium which can leak through the glass, but is stopped by the metal barrier.

Anodically bonded, gas impervious cavity structures fabricated in silicon

A monolithic, integrated circuit sensor combining both a differential pressure sensor and a flow sensor on the same silicon chip. The integrated circuit has a diaphragm with a number of piezo-resistive elements placed on it in the normal manner for a pressure sensor. In addition, a channel is provided between the spaces on the two sides of the diaphragm. The channel has a cross-section which is a fraction of the size of the diaphragm. In one embodiment, the channel is a hole in the diaphragm. In another embodiment, the channel is an etched groove in the frame supporting the diaphragm.

Monolithic flow sensor and pressure sensor

An improved method for forming a metal contact for a silicon sensor. First, platinum is deposited over a contact area. Then the platinum is sintered to form platinum silicide. Subsequently, titanium/tungsten (TiW) is deposited over the platinum silicide. Finally, gold is deposited over the TiW.

Silicon sensor contact with platinum silicide, titanium/tungsten and gold

A unique backside mask for the backside of a silicon wafer which is to be diced in a rectangular shape to form a silicon pressure sensor. The backside mask is shaped to extend farther towards the center from portions adjacent to corners of the rectangular shape. In one embodiment, the mask has a cross-shape. The silicon is etched to form a diaphragm, with the corners etching more due to the silicon crystalline structure. This leaves corner regions which are less sloped compared to the sides of the cavity, being substantially vertical or even recessed. A glass substrate with a hole in it is then bonded to the backside to form the sensor.

Method for forming a bonded silicon-glass pressure sensor with

An apparatus and method of operation for a self-testable accelerometer having a housing, a diaphragm for detecting movement in response to an applied force, a mass on the diaphragm, at least one capacitive plate attached to the housing and disposed such that a potential difference between the capacitive plate and the mass causes a movement of the mass, means for producing a potential difference between the mass and the capacitive plate, and at least one piezoresistive element attached to the housing and the diaphragm for sensing movement of the mass. The accelerometer's housing comprises a frame, a base and a cap with air gaps providing squeeze film damping and mechanical stops for inhibiting movements of the mass. The combination of the capability to electrostatically produce a movement of the mass and the piezoresistive sensing of that movement allows testing and calibration of the accelerometer at any stage in its manufacture or deployment without the need for external equipment such as shakers.

Self-testable micro-accelerometer and method

An apparatus and method of operation for a self-testable accelerometer having a housing, a diaphragm for detecting movement in response to an applied force, a mass on the diaphragm, at least one capacitive plate attached to the housing and disposed such that a potential difference between the capacitive plate and the mass causes a movement of the mass, electrodes for applying a potential difference between the mass and the capacitive plate, and at least one piezoresistive element attached to the housing and the diaphragm for sensing movement of the mass. The accelerometer's housing comprises a frame, a base and a cap with air gaps providing squeeze film damping and mechanical stops for inhibiting movements of the mass. The combination of the capability to electrostatically produce a movement of the mass and the piezoresistive sensing of that movement allows testing and calibration of the accelerometer at any stage in its manufacture or deployment without the need for external equipment such as shakers.

Self-testable micro-accelerometer

A dynamic force measurement system for taking a series of force measurements of a force applied against a sensor device whereby to determine, record, display and store the sequence of force measurements. The sensor device is adapted to respond to said force and provide an electronic force signal which is representative thereof. The dynamic force measurement system includes a central processing unit for operating a computer program, having data and program instruction storage means, graphic display and user interface means. A sensor interface device provides for the connecting of the sensor device to the central processing unit. The sensor interface device includes means for monitoring the force signal generated by the sensor device, converting the signal to a numerical binary format for recording in intermediate storage means within the sensor interface device for ultimate transfer to the central processing unit for display, statistical analysis and storage.

Dynamic force measurement system

A semiconductor transducer (10) including a substrate having a well (18) formed in one surface thereof and a semiconductor layer (14) having a first surface (26) bonded to the substrate about the periphery of the well to form a diaphragm (30) and a second surface (28) which is substantially parallel to the first surface and has a pedestal (16) projecting therefrom which is disposed above the well. The side walls (32) of the pedestal are substantially orthogonal to the second surface of the semiconductor layer and are formed by sawing edge portions of said semiconductor layer. The substrate includes structures (38) which extend upward from the bottom of the well to limit the deflection of the diaphragm.

Method of making a semiconductor transducer

A trimmable microminiature force-sensitive switching device for detecting the state of external conditions, such as pressure, acceleration and temperature, is disclosed. The device includes a silicon substrate having a reduced-thickness, deflectable member adapted to change its deflection in response to changes in the external condition to be detected. Increasing deflection of the member establishes electrical contact between a common contact and first one, then progressively more, spaced electrical contacts of a plurality of switches. Each of the spaced electrical contacts is connected to a common terminal. Trimming of the switching device is accomplished by application of a preselected external force, such as pressure, that causes the deflection of the deflectable member and the closing of one or more of the switches. Electrical energy is then applied to the external terminal of the common contact and the external terminal of the common terminal of the fusible links, such that current flows through the switches that have closed and through their associated fusible links, causing those fusible links to open circuit, thereby precluding the subsequent detection of external conditions whose level is at or below the preselected level applied during trimming of the device.

Trimmable microminiature force-sensitive switch

A semiconductor transducer (10) including a substrate having a well (18) formed in one surface thereof and a semiconductor layer (14) having a first surface (26) bonded to the substrate about the periphery of the well to form a diaphragm (30) and a second surface (28) which is substantially coplanar to the first surface and has a pedestal (16) projecting therefrom which is disposed above the well. The side walls (32) of the pedestal are substantially orthogonal to the second surface of the semiconductor layer. Means (34) are provided for sensing the deflection of the diaphragm as a function of force applied to the pedestal. The substrate includes protrusions (38) which extend upward from the bottom of the well to limit the deflection of the diaphragm.

Semiconductor transducer

An integrated circuit capacitive transducer measures at least one parameter of a medium to which it is exposed. A variable capacitor has a capacitance which varies as a function of the measured parameter and is charged by source of reference potential. The charge on the variable capacitor is then transferred to a second capacitor having a fixed reference capacitance. The voltage developed across the second capacitor by the charge transferred thereto is then a function of the capacitance of the first capacitor. Therefore, the voltage is also a function of the parameter being measured. The capacitance transducer may also include a further variable capacitor for measuring the difference of parameters between two mediums.

Capacitive transducer and method

A system for monitoring vehicle tire pressure, or the like. The system includes a transmitter and a receiver mounted on the vehicle body, and magnetically coupled inductor and enhancer circuits carried on the vehicle wheel. The inductor circuit contains an open/closed condition switch which is responsive to tire pressure. The transmitter signal, acting through the inductor and enhancer circuits, produces a response voltage in the receiver which varies at a selected transmitter frequency according to the condition of the switch. In one embodiment of the invention, the inductor and enhancer circuits are tuned to enhance the response voltage in the receiver, at a selected transmitter frequency and at one inductor circuit switch condition. In a second embodiment, the inductor and enhancer circuits are tuned to produce receiver signals which have one signal-to-noise ratio peak at one transmitter frequency and with the pressure switch in one condition, and a second signal-to-noise ratio peak, at a second transmitter frequency and with the switch in its other condition.

Growing community of inventors

Fremont, CA, United States of America

Henry V Allen