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: An airflow meter has a member that defines a bypass passage. The bypass passage has a sensing passage in which a sensor tip is disposed. The sensing passage is restricted in at least a lateral direction that is a direction perpendicular to both a longitudinal direction of the sensing passage and a perpendicular direction perpendicular to the surface of the sensor tip. This arrangement defines relatively wider distance in the perpendicular direction on the sensor tip.

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 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 sensor includes a first insulating layer, a second insulating layer having an opening, a plurality of metal wirings, and a plurality of electrodes. Each metal wiring has a contacting area. Each metal wiring is located between the first and second insulating layers. Each electrode has a bonding region located separately from the contacting area. The electrodes are in electrical connect with the contacting areas through the openings. A part of each metal wiring is located beneath each bonding region. The electrodes include any of aluminum, two metals of gold and titan, or three metals of gold, nickel, and titan. When the electrodes include aluminum, the electrodes are annealed such that the surface roughness of the electrode is smaller than 100 angstroms. When the electrodes include the two or three metals, the electrodes are annealed in an atmosphere that a partial pressure of oxygen is lower than 10−1 Pa.

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 sensor includes a first insulating layer, a second insulating layer having an opening, a plurality of metal wirings, and a plurality of electrodes. Each metal wiring has a contacting area. Each metal wiring is located between the first and second insulating layers. Each electrode has a bonding region located separately from the contacting area. The electrodes are in electrical connect with the contacting areas through the openings. A part of each metal wiring is located beneath each bonding region. The electrodes include any of aluminum, two metals of gold and titan, or three metals of gold, nickel, and titan. When the electrodes include aluminum, the electrodes are annealed such that the surface roughness of the electrode is smaller than 100 angstroms. When the electrodes include the two or three metals, the electrodes are annealed in an atmosphere that a partial pressure of oxygen is lower than 10−1 Pa.

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: A more reliable gas sensor includes a support film formed on a surface of a substrate and a heater electrode. Surrounding the heater electrode is a heater electrical insulation layer 4. Detection electrodes are formed above the electrical insulation layer. A flat insulating layer is formed over the heater insulation layer, and surfaces of the detection electrodes are exposed and flush with the upper surface of the flat insulating layer. A sensitive film is formed above the flat insulating layer in contact with the surfaces of the detection electrodes. A hollow cavity is formed in the substrate.

Abstract: A semiconductor dynamic quantity sensor includes a semiconductor support substrate having a specific resistance equal to or less than 3&OHgr; cm. An insulation film is provided on the support substrate and a semiconductor layer is provided on the support substrate with the insulation film interposed therebetween. The semiconductor layer has a specific resistance equal to or less than 3&OHgr; cm. A movable electrode is provided in the semiconductor layer to be displaced according to a dynamic quantity acting thereto. A fixed electrode is fixedly provided in the semiconductor layer to make a specific gap with the movable electrode and to from a capacitor with the movable electrode. The capacitor has a capacity that changes in response to displacement of the movable electrode to detect the dynamic quantity.

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 a method for manufacturing a semiconductor acceleration sensor, a movable portion including a mass portion and movable electrodes is formed in a single crystal silicon thin film provided on a silicon wafer through an insulation film by etching both the single crystal silicon thin film and the silicon wafer. In this case, the movable portion is finally defined at a movable portion defining step that is carried out in a vapor phase atmosphere. Accordingly, the movable portion is prevented from sticking to other regions due to etchant during the manufacture thereof.

Abstract: In a method for manufacturing a semiconductor acceleration sensor, a movable portion including a mass portion and movable electrodes is formed in a single crystal silicon thin film provided on a silicon wafer through an insulation film by etching both the single crystal silicon thin film and the silicon wafer. In this case, the movable portion is finally defined at a movable portion defining step that is carried out in a vapor phase atmosphere. Accordingly, the movable portion is prevented from sticking to other regions due to etchant during the manufacture thereof.

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 accelerometer device is formed on an SOI substrate by micro-machining. A movable unit is supported at both ends, and a weight portion is movable in response to acceleration exerted in the detection direction. A movable electrode is formed in a comb shape integrally with the weight portion. A pair of fixed electrodes in a comb shape are cantilevered and interleaved with the movable electrode to face the movable electrode. A plurality of through holes is provided in the electrodes so that the electrodes have Rahmen structure which is a series of rectangular frames. This structure reduces the weight of each electrode while increasing the strength against twist force. The electrodes are less likely from breaking in response to an acceleration exerted in a direction perpendicular to the normal detection direction because of reduced weight.

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 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 including a movable member beam structure having a reduced deflection characteristic. The sensor includes a movable beam structure film suspended from a semiconductor substrate, with a gap interposed between the beam structure film and the substrate. The beam structure film is composed of a plurality of film layers that are laminated in a direction of film thickness. Further, a stress relieving layer is interposed between respective films to reduce overall internal stress on the structure.

Abstract: A polysilicon thin film is formed on a silicon substrate by LPCVD technique. At this time, by a performing film formation at a low temperature of approximately 620.degree. C., for example, an irregularities portion is formed on the surface thereof. A silicon oxide film that serves as a sacrificial layer is formed thereon and, on this sacrificial layer, a polysilicon thin film that serves as a movable portion forming thin film is formed. Then, the silicon oxide film beneath this polysilicon thin film is removed by wet etching to thereby form a movable portion. As a result, the movable portion of a beam structure that is composed of the thin film is disposed over the silicon substrate at a prescribed distance therefrom. Although an etchant-replacing liquid enters between the movable portion and the substrate whereby the movable portion is attracted toward the substrate, the movable portion is prevented from adhering to the substrate by means of the irregularities portion.

Abstract: A semiconductor acceleration sensor according to the present invention performs acceleration detection by means of detecting increase or decrease in electrical current flowing between fixed electrodes formed on a semiconductor substrate taking a movable section in a movable state supported on the semiconductor substrate as a gate electrode. Two transistor structures are utilized in this detection. Current between fixed electrodes in one transistor structure increases when the movable section is subjected to acceleration and is displaced. At that time, current between fixed electrodes in the other transistor structure decreases. These two transistor structures are disposed proximately. By means of this proximate disposition, fluctuations in characteristics of both transistors are reduced, and by means of acceleration detection by differential type, temperature characteristics of the two transistors can be canceled favorably.