Abstract: A flow sensor for detecting flow of fluid includes a thin film portion. The thin film portion has a heater and a detector for detecting temperature around the heater. The heater is made of semiconductor. This flow sensor has high sensor sensitivity with low energy consumption. Further, the sensor has high detection accuracy, and the thin film portion has high endurance. Furthermore, the flow sensor with a passivation film has appropriate thickness so as to improve strength of a thin film portion.

Abstract: A semiconductor device, which can prevent a current capability from deteriorating with time, is disclosed. A P-channel type LDMOS is formed in an N-type monocrystal silicon substrate. The P-channel type LDMOS includes: a P-type impurity diffusion layer formed in a well shape so as to reach a predetermined depth; a channel well layer formed by double-diffusing N-type impurities; a source diffusion layer; a potential fixing electrode; drain-contact electrode; a LOCOS oxide film; a gate electrode; a drain electrode; a source electrode; and so on. Especially, the gate electrode is formed so as to overlap onto the LOCOS oxide film, and its protrusion amount onto the LOCOS oxide film (gate overlap length O/L) is set to about 10 &mgr;m, which is substantially ½ of a width size of the LOCOS oxide film.

Abstract: A thin-film type flow sensor having a thin-film part in which a plurality of patterned resistor films are sandwiched between a pair of insulator films. The resistance ratios among the resistor films are minimized from one sensor to another made from the same wafer. The flow sensor has a lower insulator film, the resistor films, and an upper film laminated in succession on a substrate. The resistor films include a patterned fluid thermometer, a temperature detector, and a heater. The heater has a wiring configuration in which resistor elements are connected in a parallel manner. The wiring widths of the heater and the thermometer can thus be made identical, so that the resistance ratios become invariant over the wafer surface, irrespective of a disparity in etching variations.

Abstract: A flow sensor, which includes a diaphragm, is made such that the diaphragm is flat or outwardly deformed to allow fluid flow rate measurements at higher flow rates. The diaphragm is made of an upper set of insulating films, electric devices, and a lower set of insulating films. The component layers of the diaphragm are formed such that the average stress in the upper set of insulating films is more compressive than the average stress in the lower set of insulating films.

Abstract: A flow meter is formed with a passage for introducing and carrying air to measure and has a sensing part disposed in the passage for measuring a flow rate of the air. A contraction part is formed on an inner surface of the passage so that the contraction part faces the sensing part. The contraction part narrows the flow of the air flowing near the sensing part. A flat surface of the contraction part is formed in parallel with the surface of the sensing part and at least upstream of the sensing part. Thus, collision of particles against the sensing part and adhesion of contaminants to the sensing pert are inhibited. Meanwhile, the flow rate of the air is measured stably and accurately.

Abstract: A flow sensor, which can detect flow velocity in a wide range including high flow velocity area with simple structure. A flow sensor includes a substrate having a hollow portion; and a thin film structure portion provided above the hollow portion. The thin film structure portion is provided with a heater formed in a center portion, an upper and a lower stream temperature detectors for detecting temperature of the fluid, a fluid thermometer for detecting temperature of the fluid, and thermal couple films provided on the substrate at a portion, where is between the heater and both temperature detectors. According to this structure, the thermal couple films enhance thermal coupling between the heater and the temperature detectors.

Abstract: A flow meter is formed with a passage for introducing and carrying air to measure and has a sensing part disposed in the passage for measuring a flow rate of the air. A contraction part is formed on an inner surface of the passage so that the contraction part faces the sensing part. The contraction part narrows the flow of the air flowing near the sensing part. A flat surface of the contraction part is formed in parallel with the surface of the sensing part and at least upstream of the sensing part. Thus, collision of particles against the sensing part and adhesion of contaminants to the sensing pert are inhibited. Meanwhile, the flow rate of the air is measured stably and accurately.

Abstract: A sensor for measuring a physical amount such as an amount of air includes a membrane structure composed of metal stripes sandwiched between first and second insulating layers. A metal layer made of platinum or the like is formed on the first insulating layer and then heat-treated to improve its properties. Then, the metal layer is etched into a form of the metal stripes. The second insulating layer made of a material such as silicon dioxide is formed on the etched metal stripes. Since the metal layer is heat-treated before it is etched into the form of metal stripes, the metal stripes are not deformed by the heat-treatment. The second insulating layer can be formed on the metal stripes without generating cracks in the second insulating layer.

Abstract: A flow sensor, which includes a diaphragm, is made such that the diaphragm is flat or outwardly deformed to allow fluid flow rate measurements at higher flow rates. The diaphragm is made of an upper set of insulating films, electric devices, and a lower set of insulating films. The component layers of the diaphragm are formed such that the average stress in the upper set of insulating films is more compressive than the average stress in the lower set of insulating films.

Abstract: A thin-film type flow sensor having a thin-film part in which a plurality of patterned resistor films are sandwiched between a pair of insulator films. The resistance ratios among the resistor films are minimized from one sensor to another made from the same wafer. The flow sensor has a lower insulator film, the resistor films, and an upper film laminated in succession on a substrate. The resistor films include a patterned fluid thermometer, a temperature detector, and a heater. The heater has a wiring configuration in which resistor elements are connected in a parallel manner. The wiring widths of the heater and the thermometer can thus be made identical, so that the resistance ratios become invariant over the wafer surface, irrespective of a disparity in etching variations.

Abstract: In a sensor chip for a fluid flow sensor, a thin film portion is formed above a hollow cavity portion while leaving thin film layers formed on the surface of a substrate. A conductor is provided on the inner wall face of a through hole formed to penetrate the substrate to thereby electrically connect a detecting portion constituted by a conductor film in the thin film layers and a substrate conductor portion formed on the rear face side of the through hole. The surface of a circuit board is formed with a control circuit and a base conductor portion electrically connected to the control circuit. The sensor chip and the circuit board are layered and the substrate conductor portion and the base conductor portion are electrically connected.

Abstract: A sensor for measuring a physical amount such as an amount of air includes a membrane structure composed of metal stripes sandwiched between first and second insulating layers. A metal layer made of platinum or the like is formed on the first insulating layer and then heat-treated to improve its properties. Then, the metal layer is etched into a form of the metal stripes. The second insulating layer made of a material such as silicon dioxide is formed on the etched metal stripes. Since the metal layer is heat-treated before it is etched into the form of metal stripes, the metal stripes are not deformed by the heat-treatment. The second insulating layer can be formed on the metal stripes without generating cracks in the second insulating layer.

Abstract: In the method for manufacturing a semiconductor substrate, a concavity and a connecting hole for connecting the concavity to the outside are formed on a lower face side of a first substrate, and the first substrate is laminated with a second substrate in an atmosphere at atmospheric pressure. A diaphragm is formed by thinning the first substrate from its upper face by polishing. A sealing hole reaching to the connecting hole is formed from the upper face of the first substrate. An oxide film is formed in the sealing hole in a vacuum, whereby the connecting hole is sealed while the pressure of the pressure reference chamber is reduced to a vacuum. In this way, since the pressure reference chamber is pressure-reduced in a final stage, the diaphragm can be prevented from deforming due to pressure difference during polishing.

Abstract: A semiconductor acceleration sensor, which prevents an adhesion of a movable portion to a fixed portion due to an electrostatic force generated during being handled. The acceleration sensor has a sensor portion and a handling portion. The sensor portion has a first semiconductor layer; a movable portion including a weight portion supported to the first semiconductor layer for moving in accordance with an acceleration externally applied thereto and movable electrodes integrally formed with the weight portion; and fixed electrodes having a detection surface confronted to a detection surface of the movable electrodes and supported to the first semiconductor layer. The handling portion is to be contacted during being handled, and is provided at surrounding portion of the sensor portion with a trench interposed therebetween. The sensor portion is electrically insulated from the handling portion by the trench.

Abstract: A semiconductor physical quantity sensor includes a substrate, a beam-structure movable portion and a fixed portion. The beam-structure movable portion is suspended by four anchors formed of polycrystalline films. A rectangular mass is suspended between beams. Movable electrodes project from both sides of the mass. First fixed electrodes and second fixed electrodes are fixedly provided on the surface of the substrate. The substrate has a laminated structure, wherein an oxide film, attaching film, insulating films, conductive film and insulating film are laminated on the substrate. An anchor formed from the conductive film is electrically connected to the attaching film. An electrode pad made of an aluminum film is provided the above the anchor. Because this structure enables the potential of the attaching film to be fixed, parasitic capacitance can be decreased.

Abstract: The present invention provides a semiconductor physical-quantity sensor which can perform measurement of high accuracy without occurrence of deformation or displacement of a fixed electrode for vibration use even if voltage applied to the fixed electrode for vibration use is changed, and which can increase a dielectric breakdown voltage between the fixed electrode for vibration use and a substrate without varying a thickness of an insulative sacrificial layer or causing sacrificial-layer etching time to be affected. A semiconductor physical-quantity sensor according to the present invention forms an electrode-anchor portion on a sufficiently thick insulation film and causes dielectric breakdown voltage with a semiconductor substrate to be increased. In particular, the sufficiently thick insulation film is given by a LOCOS oxide film formed during sensor detection-circuit fabrication or separation of a diffusion electrode.

Abstract: A silicon layer provided in a silicon substrate through a buried oxide film includes a silicon island partitioned by a trench. A surface of the silicon island in the trench is covered with a side wall oxide film, and LDMOS transistors are formed in the trench. A first impurity-doped polysilicon layer for applying a substrate potential is disposed between the buried oxide film and the substrate, and a second impurity-doped polysilicon layer is buried in the trench to communicate with the first impurity-doped polysilicon layer. Further, electrodes for applying the substrate potential are disposed on the second impurity-doped polysilicon layer. Accordingly, the substrate potential can be readily applied from the surface of the silicon layer.

Abstract: In a method of manufacturing a dynamic amount sensor including a beam structure and a fixed electrode which are respectively supported by anchor parts of a substrate, opening portions are formed on a first semiconductor substrate where the anchor parts are to be formed. Each of the opening portions is composed of a plurality of stripe-like openings. Then a first thin film for forming the anchor parts and a second thin film are formed on the first semiconductor substrate in that order. After the surface of the second thin film is polished, a second semiconductor substrate is bonded to the polished surface of the second thin film. In this method, because the opening portions are composed of the plurality of stripe-like openings, the second thin film is flattened without having any steps thereon.

Abstract: A semiconductor physical quantity sensor includes a substrate and a beam structure having movable electrodes and spacing a given distance from an upper surface of the substrate. First fixed electrodes and second fixed electrodes are fixedly provided on the upper surface of the substrate. Each first fixed electrode faces one side of the corresponding movable electrode, while each second fixed electrode faces the other side of the corresponding movable electrode. A laminated structure of a lower layer insulating film, conductive films and an upper layer insulating film is arranged at an upper portion of the substrate. The conductive layers form a first wiring pattern for the first fixed electrodes, a second wiring pattern for the second fixed electrodes and a lower electrode. The first wiring pattern is electrically connected to the first fixed electrodes via openings formed in the upper layer insulating film and anchors of the first fixed electrodes, respectively.

Abstract: A semiconductor sensor having a thin-film structure body, in which thin-film structure is prevented from bending due to the internal stress distribution in the thickness direction, is disclosed. A silicon-oxide film is formed as a sacrificial layer on a silicon substrate, and a polycrystalline-silicon thin film is formed on the silicon-oxide film. Thereafter, phosphorus (P) is ion-implanted in the surface of the polycrystalline-silicon thin film, and thereby the surface state of the polycrystalline-silicon thin film is modified. A portion of distribution of stress existing in the thickness direction of the polycrystalline-silicon thin film is changed by this modification, and stress distribution is adjusted. By removal of the silicon-oxide film, a movable member of the polycrystalline-silicon thin film is disposed above the silicon substrate with a gap interposed therebetween.