Abstract: A micromachined fluid sensing device and a method for its fabrication. The sensing device incorporates a bypass passage, preferably an integral bypass passage within the device, that enables a volume of fluid to be delivered to the device, with a limited portion of the fluid passing through a passage within the device in which one or more properties of the fluid are sensed, such as but not limited to density, specific gravity, and chemical concentrations. The device is suitable for monitoring the fuel concentration in a fuel mixture for a fuel cell.

Abstract: A method and device for assessing the viscosity of a fluid. The method and device utilize a tube with a vibrating freestanding portion into which the fluid is introduced, and relies on sensing the influence that the fluid has on the vibrational movement of the tube to assess the viscosity of the fluid. For this purpose, the freestanding portion is preferably driven at or near a resonant frequency, movement of the freestanding portion is sensed, and the viscosity of a fluid within the tube is assessed by ascertaining the damping effect the fluid has on movement of the freestanding portion at or near the resonant frequency.

Abstract: A method and device for performing lysing on a cell-containing fluid, in which the fluid flows through a vibrating micromachined tube to physically rupture the cell walls (mechanical lysis), and/or to mix, agitate or homogenize the fluid during chemical lysis, and/or to mix, agitate or homogenize the lysate for analysis or other processing after lysing. The tube includes a freestanding portion spaced apart from a surface of a substrate on which the tube is formed. The device further includes means for vibrating the freestanding portion of the tube at a level sufficient to rupture the walls of cells in a fluid flowing through the freestanding portion (for mechanical lysing) or to mix the fluid and a chemical lysing additive within the freestanding portion (for chemical lysing).

Abstract: A fluid delivery system capable of delivering a precise amount of fluid and monitor certain properties of the fluid so that the correct fluid is safely delivered to its intended destination. The system makes use of a flow sensor comprising a freestanding tube portion vibrated at a resonant frequency, wherein the resonant frequency corresponds to the density of the fluid flowing through the tube portion and the tube portion exhibits a degree of twist that varies with the mass flow rate of the fluid flowing therethrough. Movement of the tube portion is then sensed to produce a first output signal corresponding to the fluid density and a second output signal corresponding to the mass flow rate. The system is also equipped to measure elapsed time and to stop fluid flow in response to either of the first and second output signals.

Abstract: A method for preventing contamination, oxidation and gas absorption of reactive materials, and articles formed thereby. The method generally entails depositing a first layer of a reactive material and a second layer of a substantially nonreactive material so that the second layer protects the first layer from a surrounding atmosphere. For example, the first and second layers may be deposited to form a film on a surface within a chamber that is desired to be maintained in a vacuum during use of the article. The second layer is sufficiently thin such that appropriately heating the first and second layers causes the reactive material of the first layer to become interdiffused with the nonreactive material of the second layer, to the extent that at least a portion of the reactive material is able to react and getter gases from the surrounding atmosphere.

Abstract: A microneedle and a process of forming the microneedle of single-crystal silicon-based material without the need for deposited films. The microneedle comprises a piercing end, an oppositely-disposed second end, and an internal passage having an opening adjacent the piercing end. The cross-section of the microneedle, and therefore the passage within the microneedle, is defined by first and second walls formed of doped single-crystal silicon-based material and separated by the passage, and first and second sidewalls separated by the passage, sandwiched between the first and second walls, and formed of single-crystal silicon-based material that is more lightly doped than the first and second walls.

Abstract: A method and device for assessing the viscosity of a fluid. The method and device utilize a tube with a vibrating freestanding portion into which the fluid is introduced, and relies on sensing the influence that the fluid has on the vibrational movement of the tube to assess the viscosity of the fluid. For this purpose, the freestanding portion is preferably driven at or near a resonant frequency, movement of the freestanding portion is sensed, and the viscosity of a fluid within the tube is assessed by ascertaining the damping effect the fluid has on movement of the freestanding portion at or near the resonant frequency.

Abstract: A semiconductor device and method by which a device chip with a micromachine is directly surface mounted to a circuit board. A capping chip is bonded to the device chip and encloses the micromachine. The capping chip has a first surface facing the device chip, an oppositely-disposed second surface, and electrical interconnects through the capping chip between the first and second surfaces. The electrical interconnects electrically communicate with runners on the device chip that are electrically connected to the micromachine, thereby providing a signal path from the micromachine to the exterior of the device. The capping chip further includes bond pads for electrical communication with the electrical interconnects. With the bond pads, the capping chip can be surface mounted to a circuit board by reflowing solder bumps formed on the bond pads.

Abstract: A sensing device that comprises a micromachined tube on a substrate for resonant sensing of mass flow and density of a fluid flowing through the tube. The sensing device further incorporates on the same substrate at least a second micromachined tube configured for sensing another property of the fluid, such as pressure, viscosity and/or temperature.

Abstract: A method and device for performing fluid analysis by separating cells and/or particles from a fluid, such as a biological, vehicular or industrial fluid. The device is a micromachined filtering device comprising a substrate with through-thickness vias having approximately equal diameters that prevent passage through the substrate of a first material while permitting passage through the substrate of other materials having diametrical dimensions less than the diameter of the vias. Electrodes are located on a surface of the substrate between vias so that as the first material collects at the surface of the substrate, the electrodes become electrically connected to produce an output signal in some proportion to the amount of the first material collected. The device can incorporate multiple micromachined substrates, yielding an analysis system that produces an electrical output for each of a number of properties or parameters.

Abstract: A fluid delivery system capable of delivering a precise amount of fluid and monitor certain properties of the fluid so that the correct fluid is safely delivered to its intended destination. The system makes use of a flow sensor comprising a freestanding tube portion vibrated at a resonant frequency, wherein the resonant frequency corresponds to the density of the fluid flowing through the tube portion and the tube portion exhibits a degree of twist that varies with the mass flow rate of the fluid flowing therethrough. Movement of the tube portion is then sensed to produce a first output signal corresponding to the fluid density and a second output signal corresponding to the mass flow rate. The system is also equipped to measure elapsed time and to stop fluid flow in response to either of the first and second output signals.

Abstract: A method for preventing contamination, oxidation and gas absorption of reactive materials, and articles formed thereby. The method generally entails depositing a first layer of a reactive material and a second layer of a substantially nonreactive material so that the second layer protects the first layer from a surrounding atmosphere. For example, the first and second layers may be deposited to form a film on a surface within a chamber that is desired to be maintained in a vacuum during use of the article. The second layer is sufficiently thin such that appropriately heating the first and second layers causes the reactive material of the first layer to become interdiffused with the nonreactive material of the second layer, to the extent that at least a portion of the reactive material is able to react and getter gases from the surrounding atmosphere.

Abstract: A method and device for performing fluid analysis by separating cells and/or particles from a fluid, such as a biological, vehicular or industrial fluid. The device is a micromachined filtering device comprising a substrate with through-thickness vias having approximately equal diameters that prevent passage through the substrate of a first material while permitting passage through the substrate of other materials having diametrical dimensions less than the diameter of the vias. Electrodes are located on a surface of the substrate between vias so that as the first material collects at the surface of the substrate, the electrodes become electrically connected to produce an output signal in some proportion to the amount of the first material collected. The device can incorporate multiple micromachined substrates, yielding an analysis system that produces an electrical output for each of a number of properties or parameters.

Abstract: A sensing device that comprises a micromachined tube on a substrate for resonant sensing of mass flow and density of a fluid flowing through the tube. The sensing device further incorporates on the same substrate at least a second micromachined tube configured for sensing another property of the fluid, such as pressure, viscosity and/or temperature.

Abstract: A microneedle and a process of forming the microneedle of single-crystal silicon-based material without the need for deposited films. The microneedle comprises a piercing end, an oppositely-disposed second end, and an internal passage having an opening adjacent the piercing end. The cross-section of the microneedle, and therefore the passage within the microneedle, is defined by first and second walls formed of doped single-crystal silicon-based material and separated by the passage, and first and second sidewalls separated by the passage, sandwiched between the first and second walls, and formed of single-crystal silicon-based material that is more lightly doped than the first and second walls.

Abstract: A method and device for performing lysing on a cell-containing fluid, in which the fluid flows through a vibrating micromachined tube to physically rupture the cell walls (mechanical lysis), and/or to mix, agitate or homogenize the fluid during chemical lysis, and/or to mix, agitate or homogenize the lysate for analysis or other processing after lysing. The tube includes a freestanding portion spaced apart from a surface of a substrate on which the tube is formed. The device further includes means for vibrating the freestanding portion of the tube at a level sufficient to rupture the walls of cells in a fluid flowing through the freestanding portion (for mechanical lysing) or to mix the fluid and a chemical lysing additive within the freestanding portion (for chemical lysing).

Abstract: A multi-sensor module (10) includes a housing (12) with a plurality of vehicle operating condition sensors (S1-SN) mounted therein and a signal processing circuit (20, 26, 30) also mounted therein which receives sensor signals provided by the plurality of sensors (S1-SN). The signal processing circuit (20, 26, 30) is operable to produce at an output thereof (38) a time-division multiplexed signal representative of the various sensor signals according to a vehicle data bus communications protocol. The signal processing circuit output is connected to an electrical connector (36) adapted for connection to an existing vehicle data bus (18) which is further connected to a vehicle control computer (16). The signal processing circuit (20, 26, 30) is accordingly operable to broadcast on the vehicle data bus (18) sensor information provided by each of the sensors (S1-SN) mounted within the module (10).

Abstract: A method by which semiconductor wafers (10, 12) can be solder bonded to form a semiconductor device, such as a sensor with a micromachined structure (14). The method entails forming a solderable ring (18) on the mating surface of a device wafer (10), such that the solderable ring (18) circumscribes the micromachine (14) on the wafer (10). A solderable layer (20, 26, 28) is formed on a capping wafer (12), such that at least the mating surface (24) of the capping wafer (12) is entirely covered by the solderable layer (20, 26, 28). The solderable layer (20, 26, 28) can be formed by etching the mating surface (24) of the capping wafer (12) to form a recess (16) circumscribed by the mating surface (24), and then forming the solderable layer (26) to cover the mating surface (24) and the recess (16) of the capping wafer (12).

Abstract: A sensor (10) having polysilicon strain-sensing elements (20) on a metal diaphragm (16). A thick-film insulating layer (18) covers the metal diaphragm (16), and thin-film polysilicon resistive elements (20) are formed on the thick-film insulating layer (18). Thick-film conductors (22) are formed on the thick-film insulating layer (18) and contact the thin-film polysilicon resistive elements (20) to form electrical interconnects to the resistive elements (20). The thick-film conductors (22) preferably contain silicon in order to reduce diffusion of silicon from the polysilicon resistive elements (20). The thick-film insulating layer (18) may be made up of a number of individual thick-film layers, the uppermost of which is stable and nonreactive with the thin-film polysilicon resistive elements (20) and the thick-film conductors (22) at temperatures of at least 600.degree. C. A passivation layer (24) overlies the thin-film polysilicon resistive elements (20) and the thick-film conductors (22).

Abstract: An all-silicon monolithic capacitive absolute pressure-sensing device and method for making the same. The device employs a single-crystal silicon diaphragm that serves at a flexible capacitor plate of a variable capacitor. The diaphragm is bonded to a single-crystal silicon wafer to overlie a cavity etched into the wafer. A fixed capacitor plate of the variable capacitor is formed by a heavily-doped region at the bottom of the cavity. A thin dielectric layer is grown on the fixed capacitor plate to complete the capacitor. The cavity has a minimal depth such that the fixed capacitor plate provides overpressure protection for the diaphragm. At least a portion of the operating range of the pressure sensor occurs while the diaphragm is contacting the doped region. As a result, the capacitive output signal of the pressure sensor is produced by changes in contact area between the diaphragm and a thin dielectric situated on the doped region in response to pressure applied to the diaphragm.