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 diaphragm that distorts according to pressure applied thereon and a signal processor circuit are formed on a semiconductor substrate having an (110)-surface-orientation. Stain gauges converting the diaphragm distortion into an electric signal and forming a bridge circuit are formed on the diaphragm. The electric signal from the bridge circuit is processed by the signal processor circuit. A pair of transistors constituting an input circuit of an amplifier in the signal processor circuit are positioned on the substrate to equalize their source-drain current directions. Thermal stress influence on the sensor outputs is minimized since sensor components are formed on the substrate having the (110)-surface orientation, and thereby the pressure applied to the diaphragm is accurately detected.

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 semiconductor pressure sensor has a recess formed on a semiconductor substrate. The recess has a sidewall, a bottom wall that serves as a diaphragm for detecting a pressure, and a corner portion provided between the sidewall and the bottom wall and having a radius of curvature R.

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. ALOCOS 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 light-receiving element having a light-receiving portion is formed on a chip surface. A digital circuit element, an analog circuit element and a circuit adjusting element are provided for cooperatively processing a detection signal produced from the light-receiving element. And, a light-shielding film is provided for selectively setting a light-receiving region on the chip surface.

Abstract: A pressure detecting apparatus has a single-crystal semiconductor sensor chip disposed on a metallic diaphragm through a low melting point glass. The sensor chip has a planar shape selected from a circular shape, a first polygonal shape having more than five sides and having interior angles all less than 180°, and a second polygonal shape having a ratio of a circumscribed circle diameter relative to an inscribed circle diameter being less than 1.2. Four strain gauge resistors are disposed on X, Y axes passing through a center point O of the sensor chip in parallel with <110> directions. Accordingly, thermal stress is reduced not to adversely affect a detection error and simultaneously high sensitivity is provided.

Abstract: An acceleration sensor has a ring-shaped movable electrode connected to an anchor part via beams and a fixed electrode facing the ring-shaped movable electrode defining a specific interval, which are disposed on a substrate. The movable electrode is displaced by acceleration approximately in parallel to the substrate and contacts the fixed electrode, so that the acceleration is detected. The fixed electrode is divided into a detecting fixed electrode for contacting the movable electrode and a sensitivity controlling fixed electrode insulated from the detecting fixed electrode. Accordingly, potential differences between the movable electrode and the detecting fixed electrode and between the movable electrode and the sensitivity controlling fixed electrode are independently controlled to control sensitivity of acceleration.

Abstract: An etching method for a silicon substrate, which can easily smooth the etching surface of the (110)-oriented silicon, is disclosed. A container is filled with KOH solution. In the KOH solution is immersed a (110)-oriented silicon wafer having a PN junction and is also disposed a platinum electrode plate to face the silicon wafer. To between a platinum electrode of the silicon wafer and the platinum electrode plate are connected a constant voltage power source, an ammeter and a contact in series. A controller starts etching from one surface on which the PN junction is formed, and terminates voltage application when the specified time lapses after the formation of an anodic oxide film is equilibrated with the etching of the anodic oxide film on the etching surface on the PN junction part.

Abstract: In a semiconductor pressure sensor having a diaphragm portion and strain gauges on the diaphragm portion, Al stress balance films are provided around the diaphragm portion to balance changes in stress of the strain gauges, which are produced by a change in temperature. As a result, sensor output is prevented from varying due to the change in temperature.

Abstract: In a semiconductor pressure sensor, adhesive having a Young's modulus of equal to or less than 1×104 Pa such as silicone system gel is disposed between a bottom wall of a casing and a bottom wall of a sensor chip, and a space between side walls of the sensor chip and side walls of the casing is filled with adhesive having a Young's modulus of equal to or larger than 1×104 Pa, such as silicone system adhesive or epoxy system adhesive. Accordingly, temperature characteristics of the sensor chip can be improved without causing pressure leakage.

Abstract: A semiconductor sensor mount is formed as follows: through holes are formed that penetrate a glass plate; and then the glass plate having the through holes is dipped into hydrofluoric acid etchant to smooth the inner peripheral surfaces of the respective through holes. By etching the inner peripheral surfaces of the respective through holes after the through hole formation, minute roughness and cracks formed on the inner peripheral surfaces are removed, and thereby the areas for adsorbing gas are substantially reduced. That is, vacuums within the through holes can be maintained at a high degree during the anodic bonding, whereby undesirable electric discharge phenomena are prevented even if a relatively high voltage is applied during the anodic bonding. Accordingly, the yield of products can be improved while improving productivity.

Abstract: A photo diode and a signal processing circuit are formed on a silicon substrate. The signal processing circuit comprises a PNP transistor and an NPN transistor. A region of the signal processing circuit on the silicon substrate is covered by an aluminum thin film functioning as a shielding film. A covered distance L(.mu.m) is defined as an overhang of the aluminum thin film from the edge of the PNP transistor, and is determined based on a ratio of a minimum current of the PNP transistor, which induces malfunction in the signal processing circuit under the solar radiation, to a current generated in the circuit element when subjected to the solar radiation without the aluminum thin film.

Abstract: On a back face of a silicon wafer before dicing, tapered grooves having sloped side walls are formed by anisotropic etching along with thin portions. Strain gauges are formed on each thin portion, thereby forming a sensor chip on the silicon wafer. The back face of the silicon wafer is attached to a self-adhesive seat. Thereafter, the silicon wafer is cut along the grooves by a dicing blade to divide it into each sensor chip. In dicing, the side faces of the dicing blade cut the sloped side walls of the tapered grooves. As a result, the silicon wafer is diced into individual sensor chip having no cracks and chippings.

Abstract: A diffusion gauge is formed in a surface of a silicon substrate which has a plane orientation of (110). The diffusion gauge is disposed so that a main current thereof flows along a <110> direction perpendicular to a direction in which large stress biased in one direction generates in the surface of the silicon substrate due to distortion of a base for fixing the silicon substrate. Therefore, even when the large biased stress generates in the surface of the silicon substrate, because the <110> direction in which the main current of the diffusion gauge flows is perpendicular to the direction in which the biased stress generates, there is a little change in a resistance value of the diffusion gauge. As a result, a detection error caused by the distortion of the base can be reduced.

Abstract: An etching method for a silicon substrate, which can easily smooth the etching surface of the (110)-oriented silicon, is disclosed. A container is filled with KOH solution. In the KOH solution is immersed a (110)-oriented silicon wafer having a PN junction and is also disposed a platinum electrode plate to face the silicon wafer. To between a platinum electrode of the silicon wafer and the platinum electrode plate are connected a constant voltage power source, an ammeter and a contact in series. A controller starts etching from one surface on which the PN junction is formed, and terminates voltage application when the specified time lapses after the formation of an anodic oxide film is equilibrated with the etching of the anodic oxide film on the etching surface on the PN junction part.

Abstract: A semiconductor pressure detection device includes a diaphragm formed at a portion of a P- conductivity type semiconductor substrate having a reduced thickness. Gauge resistors are formed on the surface of an N- conductivity type semiconductor layer formed on the substrate. An N+ conductivity type diffusion layer is formed in the N- conductivity type semiconductor layer to fix the electric potential of the N- conductivity type layer. The first conductivity type area surrounds the diaphragm. Therefore, when the N- conductivity type area is supplied with electric potential, the potential gradient in the N- conductivity type layer is small. Thus, the leakage current which flows to a pn junction between the gauge resistors and the N- conductivity type area is reduced.

Abstract: An acceleration sensor is constructed by a substrate, a cylindrical dead-weight movable electrode to be displaced by acceleration, a fixed electrode from the inside of which a cylinder is hollowed, a cylindrical anchor arranged on the substrate for supporting the dead-weight movable electrode with elastic transformable structural material and beams. When acceleration is applied from the outside, the cylindrical detecting face of the dead-weight movable electrode and the cylindrical detected face of the fixed electrode are in contact on a two-dimensional plane parallel to the substrate and the acceleration sensor detects the contact. A radial interval between the detecting face of the dead-weight movable electrode and the detected face of the fixed electrode is set in view of the elastic modulus of the beams so that external force can be detected isotropically and the acceleration sensor detects acceleration on a two-dimensional plane nondirectionally.

Abstract: It is an object to provide a method of fabrication for a semiconductor acceleration sensor which can prevent destruction of a movable portion during dicing. A sacrificial layer composed of silicon oxide film is formed on a silicon substrate, and a movable member composed of polycrystalline silicon is formed on the sacrificial layer. A polyimide film is applied on the movable member at room temperature and heated to approximately 350.degree. C. to harden. The movable member is supported by this polyimide film. Accordingly, etching liquid penetration holes are formed on the polyimide film. Further, the sacrificial layer disposed between the movable member and the silicon substrate is etched away by means of dipping the silicon substrate into hydrofluoric acid-based etching liquid. Thereafter, the silicon substrate is dipped into demineralized water to replace the etching liquid with demineralized water, and subsequently the silicon substrate is dried.

Abstract: A photoelectric transfer device having a light receiving element and a signal processing circuit are formed in a semiconductor substrate, a silicon oxide film is formed on the light receiving element, a first aluminum thin film is deposited on the silicon substrate, and the first aluminum thin film is patterned to make a wire connected with the signal processing circuit and a protective film placed on the silicon oxide film. Thereafter, an inter-layer insulating film is deposited on the silicon substrate while covering the protective film, a portion of the inter-layer insulating film placed on the protective film is etched and removed, a second aluminum thin film is deposited on the inter-layer insulating film and the protective film, and a portion of the second aluminum thin film placed on the protective film and the protective film are successively etched and removed.