Abstract: A micromachined structure for handling fluids with an applied high voltage, i.e. for electrophoresis, includes a glass or other highly insulative substrate on which are formed very small diameter capillary channels of e.g. silicon nitride. Due to the absence of a silicon substrate, this structure is highly electrically insulative. The silicon nitride channels are formed by a micro-machining and etch process, so that they are initially defined in an etched sacrificial silicon wafer by conformal coating of etched features in the silicon wafer with a silicon nitride layer, which is then patterned to define the desired channels. The silicon wafer is bonded to the glass substrate and the bulk of the silicon wafer is sacrificially etched away, leaving the desired silicon nitride channels with supporting silicon mesas. The remaining silicon nitride "shell" is bonded to the glass substrate and substantially duplicates the etched features in the original silicon wafer.

Abstract: Micro-machined accelerometer chips have a sensitive axis perpendicular to the principle surface of the device. In an application where the desired sensing direction is in the plane of a supporting printed circuit board, the accelerometer cannot be mounted directly on the printed circuit board and instead is mounted on a wall perpendicular to the printed circuit board. This requirement to wall-mount the sensor is eliminated by using an accelerometer chip packaged with a signal conditioning circuit in a multi layer ceramic chip carrier. Electrical connections are contained within the layers of the ceramic and terminate at a side surface of the chip carrier. Thus the accelerometer chip sits perpendicular to the printed circuit board and the ceramic chip carrier is attached directly thereto.

Abstract: A precise fluid flow meter fabricated by micromachining techniques measures a wide range of fluid flow rates. Two serial portions of an enclosed channel have different cross-sectional areas, and therefore different flow velocities. The fluid carries the thermal pulse through the flow channel to two sensor elements spaced apart along the channel downstream from the heating element. The transit time of the thermal pulse between the two sensor elements measures the fluid flow velocity.

Abstract: Micro-machined accelerometer chips have a sensitive axis perpendicular to the principle surface of the device. In an application where the desired sensing direction is in the plane of a supporting printed circuit board, the accelerometer cannot be mounted directly on the printed circuit board and instead is mounted on a wall perpendicular to the printed circuit board. This requirement to wall-mount the sensor is eliminated by using an accelerometer chip packaged with a signal conditioning circuit in a multi layer ceramic chip carrier. Electrical connections are contained within the layers of the ceramic and terminate at a side surface of the chip carrier. Thus the accelerometer chip sits perpendicular to the printed circuit board and the ceramic chip carrier is attached directly thereto.

Abstract: 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.

Abstract: A process for forming a three-dimensional structure etched in a substrate with perfect convex corners includes partitioning the structure into two features such that the exterior corners are formed by the intersection of the two features; etching the first feature; forming an etch mask on the surface and on the substrate of the etched first feature; opening a window in the etch mask on the substrate to define the second feature; and etching the second feature, thereby obtaining the desired structure.

Abstract: A method for making a groove of a precise width in a substrate material. The groove may have any cross-sectional shape. The groove is formed by initially etching the substrate material. The groove width is then measured. The measured groove width is compared to the desired groove width. Oxide is grown on the substrate in the region of the groove to adjust the width of the groove. The oxide may or may not be grown with the original etchant mask left on the substrate. Depending on whether it is desired to increase or decrease the groove width, the oxide is or is not removed. The process for increasing or decreasing groove width may be repeated any number of times as necessary to achieve a proper groove width. A number of grooves may be formed using these processes. For many applications, the groove will be covered with a plate or other type of cap to define a channel as used in flow restrictors.

Abstract: A microactuator of a silicon substrate having a frame with a central circular flexible diaphragm suspended from the substrate by a hinge. The hinge is a layer of silicon dioxide of uniform thickness which is formed by etching a groove in the silicon substrate and then conformally forming a silicon dioxide layer of uniform thickness in the groove. The substrate backside is then etched to the desired diaphragm thickness, exposing the bottom portion of the silicon dioxide layer which thereby becomes the hinge. Further a split hinge structure includes two such hinges which are parallel in part and so overlap in length, with a silicon bridge portion of the diaphragm lying therebetween. The electrical traces which extend from the frame to the central portion of the diaphragm are deposited on the silicon bridge, minimizing the mechanical stress on the traces due to hinge flexing.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: 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.

Abstract: A semiconductor microactuator has a silicon semiconductor substrate having suspension means connected thereto. The suspension means has a first layer of material having a first thermal expansion coefficient and a second layer of material having a second thermal expansion different than the first thermal expansion coefficient and may be a part of a diaphragm or a pair of connecting members. A movable element, which may be a second part of the diaphragm or a boss, is connected to the suspension to be displaced thereby as the temperature of the first and second layers of material is varied. The displacement is solely irrotational with respect to the semiconductor substrate.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corregations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.