Abstract: In an integrated pressure sensor including a semiconductor substrate having a p type single crystal silicon substrate and an n type epitaxial layer of which a portion is etched by electrochemical etching to have a diaphragm, an impurity diffusion layer piercing the n type epitaxial layer at least defining the diaphragm is formed for isolation. An etching wire is formed on the surface of the n type epitaxial layer with insulation and the first end of the etching wire extends to the inside of the surface and is connected to the n type epitaxial layer. The second opposite end extends to an edge of the semiconductor substrate. The etching wire does not cross the impurity layer inside the surface of the semiconductor substrate to prevent the etching wire from short-circuiting with the impurity diffusion layer during the electrochemical etching.

Abstract: A semiconductor sensor includes a P-type semiconductor substrate having a N-type semiconductor layer disposed on one surface of the substrate and a P-type diffused resistor disposed in the N-type semiconductor layer. A first electric voltage is applied to the N-type semiconductor layer, a second electric voltage is applied to the substrate, a third electric voltage is applied to the P-type diffused resistor. The first electric voltage is higher than the second and third electric voltages. The sensor ensures stable operation against electric leakage and high noise protection because two depletion layers are formed.

Abstract: A diaphragm-type semiconductor pressure sensor includes a substantially rectangular (110) semiconductor substrate, which has four sides, an active surface of (110) crystallographic face orientation, and a back surface, which is opposite to the active surface, of (110) crystallographic face orientation. Each of the surfaces is surrounded by the four sides. Each of the four sides is at an angle of substantially 45 degrees with a crystallographic axis of <110> orientation that is substantially parallel to the active surface. The substrate includes a diaphragm in the active surface. The diaphragm has been formed by forming a recess in the back surface. The diaphragm includes a gauge resistor. A pressure is detected on the basis of the variation in the resistance of the gauge resistor.

Abstract: A semiconductor pressure sensor includes a SOI substrate composed of first and second silicon substrates. A diaphragm portion is formed by the first silicon substrate as a bottom of a recess portion formed in the second silicon substrate. Strain gauges are formed on the diaphragm portion, and a circuit portion is formed on the first silicon substrate at a region other than the diaphragm portion. A LOCOS film for isolating the strain gauges from the circuit portion is formed on the first silicon substrate outside the outermost peripheral portion of the diaphragm portion.

Abstract: A capacitive physical load sensor includes a substrate, which has fixed electrodes, and a diaphragm, which has movable electrodes. The diaphragm is located across a gap from the substrate, and retaining parts for the diaphragm are formed around the diaphragm. Protruding parts extend into the gap from the diaphragm or from the substrate. The protruding parts support the diaphragm at different levels of deformation to alter the characteristics of the diaphragm and extend its range.

Abstract: On a substrate, first and second capacitive portions are formed to have movable diaphragms having different areas for pressure measurement and diagnostic, wherein a communication structure is provided between the cavity spaces of the first and second capacitive portions to equalize the pressure in the first capacitive space to that of the second capacitive space. The different sizes provide different sensitivity for efficient diagnostic. The first and second capacitive portions can be made in one diaphragm, wherein the second capacitive portion is formed around the first capacitive portion. The cavity spaces of the first and second capacitive portions are connected. Moreover, between the first and second capacitive spaces, an insulation portion may be formed in a ring shape to support the diaphragm portion of the first capacitive portion and the diaphragm portion the second capacitive portion with communication portions.

Abstract: A pressure sensor includes a sensor element, and a resin package member that holds the sensor element. The sensor element is constructed by a semiconductor, and is capable of externally outputting an electric signal in accordance with strain generated when force is applied thereto. The sensor element is directly adhered to the package member via an adhesive layer that has Young's modulus in a range between 2.45×103 Pa and 2.06×104 Pa. Further the adhesive layer has a thickness equal to or more than 110 &mgr;m. Accordingly, the pressure sensor effectively restricts a variation in a sensor characteristic due to a thermal change.

Abstract: An electrical capacitance pressure sensor has a lower electrode, a movable electrode, and an upper electrode. A first cavity portion is formed between the lower electrode and the movable electrode. A second cavity portion is formed between the upper electrode and the movable electrode. The substrate has an opening portion that penetrates the substrate from the first surface to the second surface thereof. The lower electrode has at least one first window portion that penetrates the lower electrode from the side of the substrate to the side of the first cavity portion and communicates the cavity portion to the opening portion of the substrate. The upper electrode has at least one second window portion that penetrates the upper electrode from the side of the cavity portion to the outside thereof to communicate the cavity portion with the outside.

Abstract: In an integrated pressure sensor including a semiconductor substrate having a p type single crystal silicon substrate and an n type epitaxial layer of which a portion is etched by electrochemical etching to have a diaphragm, an impurity diffusion layer piercing the n type epitaxial layer at least defining the diaphragm is formed for isolation. An etching wire is formed on the surface of the n type epitaxial layer with insulation and the first end of the etching wire extends to the inside of the surface and connected to the n type epitaxial layer. The second opposite end extends to an edge of the semiconductor substrate. The etching wire does not cross the impurity layer inside the surface of the semiconductor substrate to prevent the etching wire from short-circuiting with the impurity diffusion layer during the electrochemical etching.

Abstract: A semiconductor strain sensor in which a sensor element for detecting a strain signal is mounted in a resin package member, which can restrain a creep stress of the package member from affecting to the sensor element. A semiconductor strain sensor is provided with a lead frame integrally molded with a resin package member, and a sensor chip made of silicon. The sensor chip is mounted on one surface of an element mounting portion of the lead frame, and is capable of externally outputting electric signal via a wire in accordance with strain when pressure is applied. An opening portion is provided in the package member, so that the entire area of another surface of the lead frame, where positions beneath the sensor chip, is non-contacted with the package member.

Abstract: On a substrate, first and second capacitive portions are formed to have movable diaphragms having different areas for pressure measurement and diagnostic, wherein a communication structure is provided between the cavity spaces of the first and second capacitive portions to equalize the pressure in the first capacitive space to that of the second capacitive space. The different sizes provide different sensitivity for efficient diagnostic. The first and second capacitive portions can be made in one diaphragm, wherein the second capacitive portion is formed around the first capacitive portion. The cavity spaces of the first and second capacitive portions are connected. Moreover, between the first and second capacitive spaces, an insulation portion may be formed in a ring shape to support the diaphragm portion of the first capacitive portion and the diaphragm portion the second capacitive portion with communication portions.

Abstract: First and second predetermined charging voltages are applied between the movable and fixed electrodes of a capacitive type of sensor to measure first and second capacitances between the movable and fixed electrodes, respectively. The first and second electrostatic capacitances are compared to obtain a characteristic of the sensor from a result of comparison. In measuring the first and second capacitances, first and second charging voltages are generated of which magnitudes are determined in accordance with the first and second capacitances, respectively. Equalization is made between the first output voltage when the first charging voltage is applied between the movable and fixed electrodes in a predetermined normal condition of the movable electrode and the second output voltage outputted when the second charging voltage is applied between the movable and fixed electrodes in the predetermined normal condition.

Abstract: In a capacitive sensor apparatus, a capacitive sensor includes a plurality of physical-quantity-detection capacitors each having a movable electrode and a fixed electrode. A conversion device operates for converting an output signal of the capacitive sensor into an apparatus output signal. Each of the physical-quantity-detection capacitors is selectively connected and disconnected to and from the conversion device. A determination is made as to whether or not each of the physical-quantity-detection capacitors fails in response to the sensor output signal. When it is determined that first one of the physical-quantity-detection capacitors fails, the first one is disconnected from the conversion device and second one of the physical-quantity-detection capacitors is connected to the conversion device.

Abstract: An electrical capacitance pressure sensor has a lower electrode, a movable electrode, and an upper electrode. A first cavity portion is formed between the lower electrode and the movable electrode. A second cavity portion is formed between the upper electrode and the movable electrode. The substrate has an opening portion that penetrates the substrate from the first surface to the second surface thereof. The lower electrode has at least one first window portion that penetrates the lower electrode from the side of the substrate to the side of the first cavity portion and communicates the cavity portion to the opening portion of the substrate. The upper electrode has at least one second window portion that penetrates the upper electrode from the side of the cavity portion to the outside thereof to communicate the cavity portion with the outside.

Abstract: In a method for manufacturing a semiconductor pressure sensor, after a reference pressure chamber is formed inside a semiconductor substrate and a diaphragm is formed from a part of the semiconductor substrate, a heat treatment is performed to form an insulation film, an element, or the like on the semiconductor substrate. At that time, a heat treatment temperature is controlled to be lower than (−430P0+1430)° C. where P0 is an internal pressure (atm) of the reference pressure chamber at a room temperature. Accordingly, crystal defects can be prevented from being produced in the diaphragm.

Abstract: A capacitive physical load sensor includes a substrate, which has fixed electrodes, and a diaphragm, which has movable electrodes. The diaphragm is located across a gap from the substrate, and retaining parts for the diaphragm are formed around the diaphragm. Protruding parts extend into the gap from the diaphragm or from the substrate. The protruding parts support the diaphragm at different levels of deformation to alter the characteristics of the diaphragm and extend its range.

Abstract: A diaphragm-type semiconductor device includes a semiconductor substrate, a surface of which is substantially flat, a diaphragm, which covers a circular pressure reference space located on the surface, and a circular electrode layer, a middle part of which is embedded in the diaphragm. The electrode layer is larger than the space and is coaxial with the space. Therefore, internal stress is balanced between inner and outer sides of the diaphragm, and a step formed at the outer edge of the top electrode layer is separated from the diaphragm. The device also includes a step adjuster around the space on the surface. Therefore, another step formed at the outer edge of the space disappears, and a new step is formed separately from the diaphragm at the outer edge of the step adjuster. With this structure, the diaphragm has a desired flatness.

Abstract: A semiconductor sensor chip is provided with a weight portion supported in a frame via beams whereby acceleration up to substantially ±1 G can be detected by utilizing piezoresistance effect of resistor elements formed on the beams. The semiconductor sensor chip is supported by a seat having a thermal expansion coefficient equivalent to that of the semiconductor sensor chip via the frame. The frame and the seat are adhered to each other by a flexible adhesive agent mixed with a plurality of resin beads functioning as spacers and under an adhesion state, air damping of the weight portion is carried out by setting a dimension of an air gap between the weight portion and the seat to a range of 7 through 15 &mgr;m.

Abstract: A dynamic sensor includes stationary electrodes and movable electrodes facing each other and forming a capacitance therebetween. The capacitance changes in accordance with a dynamic force such as acceleration imposed on the sensor. Plural projections are formed on the stationary electrodes to avoid or suppress electrode sticking between the movable electrodes and the stationary electrodes due to an excessive impact imposed on the sensor. The projections are formed to have various heights so that higher projections first hit the movable electrodes and thereby protect lower projections. Even after the higher projections are destroyed by the excessive impact, the lower projections remain intact and serve to prevent the electrode sticking by the excessive impact which may occur later.

Abstract: A reference voltage generating circuit is constituted by resistors RE and RF each having a resistance not influenced by an application of pressure. The reference voltage generating circuit is connected between one and the other ends of a bridge circuit. A failure judgement of the bridge circuit is performed based on a comparison of a voltage difference VBC between two midpoints B and C of the bridge circuit and voltage differences VCE and VBE between a reference voltage level of the reference voltage generating circuit and the voltage levels of two midpoints B and C.