An apparatus and method for use in determining one or more fluid flow properties of a fluid in a conduit is disclosed. The apparatus includes a substrate including a barrier, a first flow sensor coupled to the substrate and a second flow sensor coupled to the substrate. The first flow sensor is located at a first sensor distance from a first barrier surface, and the second flow sensor is located a second sensor distance from the second barrier surface. The first sensor distance is substantially equal to the second sensor distance. In operation, the first flow sensor produces a first sensor signal, and the second flow sensor produces a second sensor signal. The direction of flow for the fluid is determined by comparing the first sensor signal to the second sensor signal.

A flow sensor includes a semiconductor, an electric control circuit, a lead frame, and a spacer. The spacer is disposed in a clearance between the lead frame and the semiconductor device on an opposite side from a joint portion of the semiconductor device with the lead frame on a side of the electric control circuit across the diaphragm disposed therebetween. A surface of the electric control circuit and a part of a surface of the semiconductor device is covered with resin while the air flow sensing unit is exposed. At the joint portion, the semiconductor device is attached to the lead frame via an adhesive.

A flow sensor includes a semiconductor, an electric control circuit, a lead frame, and a spacer. The spacer is disposed in a clearance between the lead frame and the semiconductor device on an opposite side from a joint portion of the semiconductor device with the lead frame on a side of the electric control circuit across the diaphragm disposed therebetween. A surface of the electric control circuit and a part of a surface of the semiconductor device is covered with resin while the air flow sensing unit is exposed. At the joint portion, the semiconductor device is attached to the lead frame via an adhesive.

A thermoresistive micro sensor device includes a semiconductor chip; a through hole, which runs through the semiconductor chip from an upper side to a lower side; electrically conductive structures, wherein the middle section of each of the electrically conductive structures spans over the through hole at the upper side of the semiconductor chip; an electrically insulating arrangement for electrically insulating the electrically conductive structures and the semiconductor chip from each other, wherein the through hole runs through the electrically insulating arrangement; and a contact arrangement including contacts, wherein each of the contacts is electrically connected to one of the first end sections or one of the second end sections, so that electrical energy is fed to at least one of the electrically conductive structures to heat the respective electrically conductive structure, and so that an electrical resistance of one of the electrically conductive structures is measured at the contact arrangement.

A thermal flow sensor chip has a heater part, and a pair of thermopiles provided so as to be opposite each other across the heater part. The heater part is famed by doping silicon with an impurity that reduces the electrical resistance. In each of the thermopiles: a silicon region is formed by doping silicon with an impurity that reduces the electrical resistance; the concentration of the impurity in a heater main part, including the lengthwise center of the heater part extending in the first direction, is lower than the concentration of the impurity in a heater outer peripheral part, the heater outer peripheral part being different from the heater main part and including a lengthwise end part of the heater part; and the concentration of the impurity in the heater main part is the same as the concentration of the impurity in at least part of the silicon region of the thermopile.

A thermal flow sensor chip has a heater part, and a pair of thermopiles provided so as to be opposite each other across the heater part. The heater part is famed by doping silicon with an impurity that reduces the electrical resistance. In each of the thermopiles: a silicon region is formed by doping silicon with an impurity that reduces the electrical resistance; the concentration of the impurity in a heater main part, including the lengthwise center of the heater part extending in the first direction, is lower than the concentration of the impurity in a heater outer peripheral part, the heater outer peripheral part being different from the heater main part and including a lengthwise end part of the heater part; and the concentration of the impurity in the heater main part is the same as the concentration of the impurity in at least part of the silicon region of the thermopile.

A thermal type sensor molded from a mold resin having an opening has a problem in that the residual stress of the mold resin in the opening causes peeling at the interface having poor adhesion. A physical quantity sensor has a construction having a semiconductor chip having a detector unit 3, a frame 8a on which the semiconductor chip is mounted, a mold resin portion 10 which encapsulates the semiconductor chip and the frame and has an opening through which the detector unit is exposed to the outside, and a stress absorbing layer 6 which is formed between an end of the opening in the mold resin portion and a wiring layer formed in the detector unit, and which is formed from a metal material that absorbs a stress from the end.

A thermal type sensor molded from a mold resin having an opening has a problem in that the residual stress of the mold resin in the opening causes peeling at the interface having poor adhesion. A physical quantity sensor has a construction having a semiconductor chip having a detector unit 3, a frame 8a on which the semiconductor chip is mounted, a mold resin portion 10 which encapsulates the semiconductor chip and the frame and has an opening through which the detector unit is exposed to the outside, and a stress absorbing layer 6 which is formed between an end of the opening in the mold resin portion and a wiring layer formed in the detector unit, and which is formed from a metal material that absorbs a stress from the end.

A flow sensor structure seals the surface of an electric control circuit and part of a semiconductor device via a manufacturing method that prevents occurrence of flash or chip crack when clamping the semiconductor device via a mold. The flow sensor structure includes a semiconductor device having an air flow sensing unit and a diaphragm, and a board or lead frame having an electric control circuit for controlling the semiconductor device, wherein a surface of the electric control circuit and part of a surface of the semiconductor device is covered with resin while having the air flow sensing unit portion exposed. The flow sensor structure may include surfaces of a resin mold, a board or a pre-mold component surrounding the semiconductor device that are continuously not in contact with three walls of the semiconductor device orthogonal to a side on which the air flow sensing unit portion is disposed.

A flow sensor structure seals the surface of an electric control circuit and part of a semiconductor device via a manufacturing method that prevents occurrence of flash or chip crack when clamping the semiconductor device via a mold. The flow sensor structure includes a semiconductor device having an air flow sensing unit and a diaphragm, and a board or lead frame having an electric control circuit for controlling the semiconductor device, wherein a surface of the electric control circuit and part of a surface of the semiconductor device is covered with resin while having the air flow sensing unit portion exposed. The flow sensor structure may include surfaces of a resin mold, a board or a pre-mold component surrounding the semiconductor device that are continuously not in contact with three walls of the semiconductor device orthogonal to a side on which the air flow sensing unit portion is disposed.