Abstract: A semiconductor dynamic quantity sensor includes a semiconductor substrate that includes a movable electrode, a pair of first fixed electrodes, and a pair of second fixed electrodes. The first and second pairs of first detection capacitances and the first and second pairs of second detection capacitances are formed by the electrodes. The dynamic quantity related to the force applied to the sensor is measured on the basis of the sum of the differential output between the first pair of the first detection capacitances, the differential output between the second pair of the first detection capacitances, the differential output between the first pair of the second detection capacitances, and the differential output between the second pair of the second detection capacitances, when the movable electrode moves along the first direction or the second direction under the force. The sum includes a relatively small amount of noises.

Abstract: In a capacitive type dynamic quantity sensor, a width of a beam in a beam portion extending in a direction that is perpendicular to a predetermined deformation direction and a gap disposed between a movable electrode and the fixed electrode in the predetermined deformation direction are approximately identical. Accordingly, manufacturing error is prevented from affecting the sensitivity of the capacitive type dynamic quantity sensor. For example, a manufacturing tolerance error of ±2.5% is allowed as a result of designing the width of the beam and the gap to be identical in length.

Abstract: A semiconductor mechanical quantity sensor includes two sensor chips (100a, 100b) having the same structure and the same characteristics formed on semiconductor substrates (10a, 10b), arranged on a circuit chip (6) in the same direction. There may be used a sensor chip having two sensors of the same structure formed in one semiconductor substrate in the same direction. The number of the sensors may be three or more. A plurality of sensors may be stacked on the semiconductor substrate or on the circuit chip, or may be arranged on both surfaces of the semiconductor substrate (10a, 10b) or the circuit chip (6).

Abstract: A semiconductor dynamic quantity sensor has a support substrate with a rectangular opening portion, and a movable electrode and fixed electrodes are respectively supported by the support substrate through supporting portions to face the opening portion. The supporting portions supporting the movable electrode are arranged in a direction approximately the same as that in which the supporting portions supporting the fixed electrodes are arranged.

Abstract: When movable electrodes of beam arrangement structures are displaced in a direction perpendicular to the surface of a support substrate in first and second capacitance constituent portions by action of an acceleration while carrier voltages are applied, the difference between a first capacitance and second capacitance is output from the support substrate through a third capacitance constituent portion. Under self-diagnosis, the voltage applying counter electrode portion of the self-diagnosis fixed capacitance constituent portion is set to a first potential, and a signal output counter electrode portion of the third capacitance constituent portion is set to a second potential different from the first potential, whereby the potential of the support substrate corresponding to the fixed electrode in the first and second capacitance constituent portions is forcedly changed.

Abstract: A pressure sensor includes a semiconductor substrate and a pedestal member such as a glass pedestal. The semiconductor substrate has a diaphragm for detecting a pressure and a thick portion positioned around the diaphragm. The pedestal member has one surface bonded to the thick portion of the semiconductor substrate and the other surface opposite to the one surface. In the pressure sensor, the pedestal member has a through hole through which pressure is introduced to the diaphragm. The through hole penetrates through the pedestal member from an opening of the other surface to the one surface of the pedestal member, and the through hole has a hole diameter that becomes smaller from the one surface toward the other surface of the pedestal member. Accordingly, it can effectively restrict foreign materials such as dusts from being introduced into the through hole of the pressure sensor.

Abstract: A method of manufacturing a semiconductor device is provided. The device is manufactured with use of an SOI (Silicon On Insulator) substrate having a first silicon layer, an oxide layer, and a second silicon layer laminated in this order. After forming a trench reaching the oxide layer from the second silicon layer, dry etching is performed, thus allowing the oxide layer located at the trench bottom to be charged at first. This charging forces etching ions to impinge upon part of the second silicon layer located laterally to the trench bottom. Such part is removed, forming a movable section. For example, ions to neutralize the electric charges are administered into the trench, so that the electric charges are removed from charged movable electrodes and their charged surrounding regions. Removing the electric charges prevents the movable section to stick to its surrounding portions.

Abstract: In a capacitive type dynamic quantity sensor, a width of a beam in a beam portion extending in a direction that is perpendicular to a predetermined deformation direction and a gap disposed between a movable electrode and the fixed electrode in the predetermined deformation direction are approximately identical. Accordingly, manufacturing error is prevented from affecting the sensitivity of the capacitive type dynamic quantity sensor. For example, a manufacturing tolerance error of ±2.5% is allowed as a result of designing the width of the beam and the gap to be identical in length.

Abstract: An acceleration sensor is formed on a top surface of a laminated silicon-on-insulator substrate. The acceleration sensor is composed of first and second capacitors each including a movable electrode that moves according to acceleration imposed thereon. The first and the second capacitors are so made that their capacitances change differently when the same acceleration is imposed and that the capacitance difference represents an amount of acceleration imposed thereon. A third capacitor having an output electrode solidly connected to the base substrate via the insulation layer is also formed on the same silicon-on-insulator substrate. An output representing amount of acceleration is taken out from the output electrode of the third capacitor.

Abstract: In a capacitive type dynamic quantity sensor, a width of a beam in a beam portion extending in a direction that is perpendicular to a predetermined deformation direction and a gap disposed between a movable electrode and the fixed electrode in the predetermined deformation direction are approximately identical. Accordingly, manufacturing error is prevented from affecting the sensitivity of the capacitive type dynamic quantity sensor. For example, a manufacturing tolerance error of ±2.5% is allowed as a result of designing the width of the beam and the gap to be identical in length.

Abstract: A capacitive dynamic quantity sensor includes a substrate, a weight, a movable electrode, an anchor, a fixed electrode, a spring, and a strain buffer. The weight is displaced by a dynamic quantity. The movable electrode is integrated with the weight. The anchor is fixed to the substrate to suspend the weight and the movable electrode above the substrate. The fixed electrode is arranged to face the movable electrode. The displacement of the movable electrode caused in response to the dynamic quantity is detected as a capacitance variation between the electrodes. The spring is located between the anchor and the weight and resiliently deforms in response to the dynamic quantity such that the movable electrode is displaced by a distance corresponding to the dynamic quantity. The strain buffer is located between the anchor and the spring to reduce the influence of a strain generated in the substrate on the spring.

Abstract: In a semiconductor acceleration sensor (S1), above one side of a first silicon substrate (10) made of a semiconductor and serving as a fixed electrode (11), a moving electrode (20) made of a semiconductor and displaceable in the thickness direction of the first silicon substrate (10) is disposed apart from and facing the first silicon substrate (10). An applied acceleration is detected on the basis of capacitance changes between the moving electrode (20) and the face of the first silicon substrate (10) accompanying displacement of the moving electrode (20). A space and an electrically insulative insulating layer (13) having a relative permittivity larger than that of air are interposed between the moving electrode (20) and the face of the first silicon substrate (10), side by side in the direction in which the moving electrode (20) and the first silicon substrate (10) are apart.

Abstract: A capacitive dynamic quantity sensor includes a substrate, a weight, a movable electrode, an anchor, a fixed electrode, a spring, and a strain buffer. The weight is displaced by a dynamic quantity. The movable electrode is integrated with the weight. The anchor is fixed to the substrate to suspend the weight and the movable electrode above the substrate. The fixed electrode is arranged to face the movable electrode. The displacement of the movable electrode caused in response to the dynamic quantity is detected as a capacitance variation between the electrodes. The spring is located between the anchor and the weight and resiliently deforms in response to the dynamic quantity such that the movable electrode is displaced by a distance corresponding to the dynamic quantity. The strain buffer is located between the anchor and the spring to reduce the influence of a strain generated in the substrate on the spring.

Abstract: In a semiconductor dynamic quantity sensor, a mass serving as a weight portion for detecting application of a dynamic quantity is divided into three masses (301, 302, 303) in series. The masses (301, 302, 303) thus divided are connected to one another by connecting beams (CB1, CB2, CB3, CB4). The masses (301, 302, 303) located at both the end portions are supported through beams (B1, B2, B3, B4) by a semiconductor substrate (1) so as to be allowed to be displaced in the direction orthogonal to the connection direction of the masses. The center mass (302) connected to the masses (301, 302, 303) through the connecting beams (CB1, CB2, CB3, CB4) is allowed to be displaced only in the connecting direction of the masses by the connecting beams (CB1, CB2, CB3, CB4).

Abstract: A physical quantity sensor detects physical quantity. The sensor includes a plurality of springs, which have different spring constants, respectively. The sensor has a wide detection range of the physical quantity without assembling multiple sensors. Therefore, the sensor can be minimized. Further, since the sensor has an excellent linearity of the output characteristics, the sensor has a wide dynamic range and a high sensitivity.

Abstract: A capacitive acceleration sensor includes a supporting substrate, a movable member, and two fixed members. The movable member moves in response to a force that acts on the movable member. Each fixed member is stationary under the force. Two capacitances are formed between the movable member and the fixed members. One of the capacitances increases while the other decreases when the movable member moves in response to the force. The force includes a substantially constant force and a variable force when an acceleration is measured using the sensor. The variable force is proportional to the acceleration. The acceleration is measured on the basis of the difference between the capacitances. The capacitances are different from each other when the force that acts on the movable member is zero to reduce the difference between the capacitances that corresponds to the substantially constant force.

Abstract: A semiconductor mechanical quantity sensor includes two sensor chips (100a, 100b) having the same structure and the same characteristics formed on semiconductor substrates (10a, 10b), arranged on a circuit chip (6) in the same direction. There may be used a sensor chip having two sensors of the same structure formed in one semiconductor substrate in the same direction. The number of the sensors may be three or more. A plurality of sensors may be stacked on the semiconductor substrate or on the circuit chip, or may be arranged on both surfaces of the semiconductor substrate (10a, 10b) or the circuit chip (6).

Abstract: A capacitive device includes a substrate, a movable electrode, and a fixed electrode. The movable electrode is located above a surface of the substrate and is movable with respect to the substrate along directions that are substantially orthogonal to the surface. The fixed electrode is stationary with respect to the substrate. When the movable electrode is displaced in a first direction that is substantially orthogonal to the surface, the total sum of area-distance quotients in the overlap between the electrodes remains substantially unchanged or decreases to provide a first reduction rate that is substantially zero or more. On the other hand, when the movable electrode is displaced in a second direction that is substantially opposite to the first direction, the total sum of area-distance quotients remains substantially unchanged or decreases to provide a second reduction rate that is substantially zero or more. The reduction rates are different from each other.

Abstract: A method of manufacturing a semiconductor device is provided. The device is manufactured with use of an SOI (Silicon On Insulator) substrate having a first silicon layer, an oxide layer, and a second silicon layer laminated in this order. After forming a trench reaching the oxide layer from the second silicon layer, dry etching is performed, thus allowing the oxide layer located at the trench bottom to be charged at first. This charging forces etching ions to impinge upon part of the second silicon layer located laterally to the trench bottom. Such part is removed, forming a movable section. For example, ions to neutralize the electric charges are administered into the trench, so that the electric charges are removed from charged movable electrodes and their charged surrounding regions. Removing the electric charges prevents the movable section to stick to its surrounding portions.

Abstract: In a dynamic quantity sensor for detecting a dynamic quantity, a movable portion having comb-shaped movable electrodes is connected to a base portion through a beam portion as a spring portion, and moves in direction Y upon receiving dynamic quantity. Comb-shaped fixed electrodes are arranged opposite to the movable electrodes through detection intervals. A Q value of vibration of the movable portion in the direction Y is smaller than {fraction (1/500)} of a resonance frequency of the movable portion in the direction Y. Therefore, free vibration of the movable portion is rapidly damped so as not to adversely affect sensor output.