JP5982578B2 - Flow sensor and flow sensor device - Google Patents

Description

  The present invention relates to a flow sensor and a flow sensor device, and more particularly, to a flow sensor and a flow sensor device including a semiconductor chip in which a flow rate detection unit is formed on a diaphragm.

An internal combustion engine such as an automobile includes an electronically controlled fuel injection device for appropriately operating the internal combustion engine by appropriately adjusting the amount of air and fuel flowing into the internal combustion engine. The electronically controlled fuel injection device is provided with a flow sensor for measuring the flow rate of air flowing into the internal combustion engine.
From the viewpoint of cost and performance, a flow sensor in which a diaphragm is formed on a semiconductor chip using a micromachining technique and a flow rate detection unit is provided on the diaphragm has been attracting attention.

  The flow rate detection unit includes a heating resistor and a resistance temperature detector, and measures the flow rate under the control of a control circuit unit provided on the same or different semiconductor chip. Such a flow rate sensor has a structure in which the flow rate detector is exposed and the periphery of the semiconductor chip is sealed with resin. When the sealing of the resin is performed by the potting method, a resin position shift or the like occurs, the mounting position of the flow sensor shifts for each flow sensor, and the performance of the flow sensor varies.

For this reason, a flow sensor that performs sealing with a resin by a resin mold is known.
An example of such a flow sensor has the following structure.
A semiconductor chip on which a flow rate detection unit is formed is mounted on the lead frame, and the semiconductor chip is covered with a resin having an opening that exposes the flow rate detection unit. The flow rate detection part of the semiconductor chip is provided on the diaphragm, and the lower side of the diaphragm is a recess. The lead frame is formed with a ventilation opening for communicating the recess on the lower side of the diaphragm with the outside of the semiconductor chip.
The reason for providing a ventilation opening in the lead frame is that the pressure in the external space around the flow rate detector and the internal pressure in the recess on the lower side of the diaphragm are the same, and the diaphragm is caused by the difference in internal and external pressure. This is to suppress the occurrence of stress on the flow rate and the deterioration of the detection accuracy of the flow rate detector (see, for example, Patent Document 1).

JP 2012-141316 A

  Since the flow rate detection unit of the flow rate sensor is installed in a space where the change in air flow is large, the internal pressure of the concave portion on the lower side of the diaphragm varies in the same manner as the external pressure around the flow rate detection unit. The fluctuation of the internal pressure of the concave portion on the lower side of the diaphragm is different in fluctuation width and timing from the fluctuation of the pressure around the flow rate detection unit. For this reason, stress is generated in the diaphragm due to the difference in fluctuation in pressure between the two, and the detection accuracy of the flow rate detection unit is lowered.

The flow sensor according to the present invention has a lead frame, a main surface, a back surface, and a peripheral side surface, a diaphragm is formed on the main surface, a recess is formed on the back surface side of the diaphragm, and a flow rate detection unit is provided on the diaphragm. A semiconductor chip that is formed and mounted on one surface of the lead frame, and a resin that exposes the flow rate detection unit and covers at least a part of the main surface or peripheral side surface of the semiconductor chip. A ventilation passage having one end communicating with the recess of the semiconductor chip and the other end disposed outside the peripheral side surface of the semiconductor chip, and the other end of the ventilation passage of the lead frame is formed on the peripheral side surface of the semiconductor chip in the resin. It communicates with a ventilation opening provided on the outside, or is arranged outside the resin.
A flow sensor device according to the present invention includes the above flow sensor and a housing that houses the flow sensor, and the housing includes a region where the flow rate detection unit of the semiconductor chip is exposed from the resin, a groove of the lead frame, It has a partition part which partitions off the area where the other end of the through hole is arranged.

  According to the present invention, the concave portion provided on the back surface side of the flow rate detection unit can be communicated with a region different from the periphery where the flow rate detection unit is exposed from the resin. For this reason, the fluctuation | variation of the internal stress of the recessed part provided in the back surface side of the flow volume detection part can be made small, and the detection accuracy of a flow volume detection part can be improved.

It is a circuit block diagram which shows one Embodiment of the circuit structure of the flow sensor by this invention. It is a top view which shows one Embodiment of the layout structure of the semiconductor chip which comprises the flow sensor by this invention. 1 shows an embodiment of a flow sensor according to the present invention, (a) is a plan view showing the structure of the flow sensor after the resin sealing step, and (b) is a sectional view taken along line IIIb-IIIb of (a). is there. The structure of the flow sensor before the resin sealing process of the flow sensor illustrated in FIG. 3 is shown, (a) is a plan view, and (b) is a sectional view taken along line IVb-IVb of (a). It is sectional drawing which shows the resin sealing process of the flow sensor in one embodiment by this invention. It is a figure which shows the prior art example of a flow sensor, (a) is a top view which shows the structure after a resin sealing process, (b) is VIb-VIb sectional view taken on the line of (a). FIG. 4 is a cross-sectional view of an embodiment of a flow sensor device according to the present invention in which the flow sensor illustrated in FIG. 3 is housed in a housing. Embodiment 2 of the flow sensor by this invention is shown, (a) is sectional drawing which shows the structure before a resin sealing process, (b) is sectional drawing which shows the structure after a resin sealing process. Embodiment 3 of the flow sensor by this invention is shown, (a) is sectional drawing which shows the structure before a resin sealing process, (b) is sectional drawing which shows the structure after a resin sealing process. Embodiment 4 of the flow sensor by this invention is shown, (a) is sectional drawing which shows the structure before a resin sealing process, (b) is sectional drawing which shows the structure after a resin sealing process. Embodiment 5 of the flow sensor by this invention is shown, (a) is sectional drawing which shows the structure before a resin sealing process, (b) is sectional drawing which shows the structure after a resin sealing process. Embodiment 6 of the flow sensor by this invention is shown, (a) is a top view which shows the structure after a resin sealing process, (b) is the XIIb-XIIb sectional view taken on the line of (a).

--Embodiment 1-
<Circuit configuration of flow sensor>
Hereinafter, an embodiment of a flow sensor and a flow sensor device of the present application will be described with reference to the drawings.
1 to 5 show Embodiment 1 of the flow sensor of the present invention. First, the circuit configuration of the flow sensor will be described.
FIG. 1 is a circuit block diagram illustrating a circuit configuration of a flow sensor according to the first embodiment. In FIG. 1, the flow sensor FS in the first embodiment is a CPU (Central Processing Unit).
1, and further includes an input circuit 2 for inputting an input signal to the CPU 1 and an output circuit 3 for outputting an output signal from the CPU 1. The flow rate sensor FS is provided with a memory 4 for storing data, and the CPU 1 can access the memory 4 and refer to the data stored in the memory 4.

  The CPU 1 is connected to the base electrode of the transistor Tr via the output circuit 3. The collector electrode of the transistor Tr is connected to the power source PS, and the emitter electrode of the transistor Tr is connected to the ground (GND) via the heating resistor HR. The transistor Tr is controlled by the CPU 1. Since the base electrode of the transistor Tr is connected to the CPU 1 via the output circuit 3, an output signal from the CPU 1 is input to the base electrode of the transistor Tr.

The current flowing through the transistor Tr is controlled by an output signal (control signal) from the CPU 1. When the current flowing through the transistor Tr is increased by the output signal from the CPU 1, the current supplied from the power source PS to the heating resistor HR is increased, and the heating amount of the heating resistor HR is increased. When the current flowing through the transistor Tr decreases due to the output signal from the CPU 1, the current supplied to the heating resistor HR decreases, and the heating amount of the heating resistor HR decreases.
As described above, the flow rate sensor FS according to the first embodiment is configured such that the amount of current flowing through the heating resistor HR is controlled by the CPU 1, and thereby the amount of heat generated from the heating resistor HR is controlled by the CPU 1. .

In the flow rate sensor FS in the first embodiment, a heater control bridge HCB is provided in order to control the current flowing through the heating resistor HR by the CPU 1. The heater control bridge HCB detects the amount of heat generated from the heating resistor HR and outputs the detection result to the input circuit 2. The CPU 1 can input the detection result from the heater control bridge HCB, and controls the current flowing through the transistor Tr based on the detection result.
Specifically, the heater control bridge HCB includes resistors R1 to R4 that form a bridge between the reference voltage Vref1 and the ground (GND). In the heater control bridge HCB configured as described above, when the gas heated by the heating resistor HR is higher than the intake air temperature by a certain temperature (ΔT, for example, 100 ° C.), the potential of the node A and the node B The resistance values of the resistors R1 to R4 are set so that the potential difference between the potentials of the resistors R1 to R4 is 0V. That is, the resistors R1 to R4 constituting the heater control bridge HCB are referred to as a component in which the resistor R1 and the resistor R3 are connected in series and a component in which the resistor R2 and the resistor R4 are connected in series. The bridge is configured so as to be connected in parallel between the voltage Vref1 and the ground (GND). A connection point between the resistor R1 and the resistor R3 is a node A, and a connection point between the resistor R2 and the resistor R4 is a node B.

  At this time, the gas heated by the heating resistor HR comes into contact with the resistor R1 constituting the heater control bridge HCB. Therefore, the resistance value of the resistor R1 constituting the heater control bridge HCB mainly changes depending on the amount of heat generated from the heating resistor HR. When the resistance value of the resistor R1 changes in this way, the potential difference between the node A and the node B changes. Since the potential difference between the node A and the node B is input to the CPU 1 via the input circuit 2, the CPU 1 controls the current flowing through the transistor Tr based on the potential difference between the node A and the node B.

  Specifically, the CPU 1 controls the amount of heat generated from the heating resistor HR by controlling the current flowing through the transistor Tr so that the potential difference between the node A and the node B becomes 0V. That is, in the flow rate sensor FS in the first embodiment, the gas heated by the heating resistor HR by the CPU 1 is higher than the intake air temperature by a certain temperature (ΔT, for example, 100 ° C.) based on the output of the heater control bridge HCB. It is configured to perform feedback control so as to maintain a constant value.

  The flow sensor FS in the first embodiment has a temperature sensor bridge TSB for detecting the gas flow rate. The temperature sensor bridge TSB is composed of four temperature measuring resistors that form a bridge between the reference voltage Vref2 and the ground (GND). The four resistance temperature detectors are composed of two upstream resistance temperature detectors UR1 and UR2, and two downstream resistance temperature detectors BR1 and BR2.

  The direction of the arrow in FIG. 1 indicates the direction in which the gas flows. The upstream resistance thermometers UR1 and UR2 are provided on the upstream side of the gas flow direction, and the downstream resistance thermometers BR1 and BR2 are provided on the downstream side. Is provided. The upstream resistance thermometers UR1 and UR2 and the downstream resistance thermometers BR1 and BR2 are arranged so that the distance to the heating resistor HR is the same.

In the temperature sensor bridge TSB, an upstream resistance temperature detector UR1 and a downstream resistance temperature detector BR1 are connected in series between the reference voltage Vref2 and the ground (GND), and the upstream resistance temperature detector UR1 and the downstream resistance temperature detector. The connection point of BR1 is node C.
An upstream resistance temperature detector UR2 and a downstream resistance temperature detector BR2 are connected in series between the ground (GND) and the reference voltage Vref2, and a connection point between the upstream resistance temperature detector UR2 and the downstream resistance temperature detector BR2 is a node. D.

  The potential of the node C and the potential of the node D are configured to be input to the CPU 1 via the input circuit 2. The upstream resistance thermometers UR1 and UR2 and the downstream resistance thermometer so that the potential difference between the potential of the node C and the potential of the node D becomes 0 V when the flow rate of the gas flowing in the arrow direction is zero. Each resistance value of BR1 and BR2 is set.

  Specifically, the upstream resistance thermometers UR1 and UR2 and the downstream resistance thermometers BR1 and BR2 are configured to have the same distance from the heating resistor HR and the same resistance value. For this reason, it can be seen that the temperature sensor bridge TSB is configured such that the potential difference between the node C and the node D is 0 V in the absence of wind regardless of the amount of heat generated by the heating resistor HR.

<Flow sensor operation>
The flow sensor FS in the first embodiment is configured as described above, and the operation thereof will be described below with reference to FIG.
First, the CPU 1 outputs an output signal (control signal) to the base electrode of the transistor Tr via the output circuit 3, thereby causing a current to flow through the transistor Tr. Then, a current flows from the power supply PS connected to the collector electrode of the transistor Tr to the heating resistor HR connected to the emitter electrode of the transistor Tr. For this reason, the heating resistor HR generates heat. The gas heated by the heat generated from the heat generating resistor HR heats the resistor R1 constituting the heater control bridge HCB.

  At this time, when the gas heated by the heating resistor HR is increased by a certain temperature (for example, 100 ° C.), the resistor is set so that the potential difference between the node A and the node B of the heater control bridge HCB becomes 0V. Each resistance value of R1 to R4 is set. For this reason, for example, when the gas heated by the heating resistor HR is increased by a certain temperature (for example, 100 ° C.), the potential difference between the node A and the node B of the heater control bridge HCB becomes 0V, This difference potential (0 V) is input to the CPU 1 via the input circuit 2. Then, the CPU 1 recognizing that the difference potential from the heater control bridge HCB is 0 V outputs an output signal (control signal) for maintaining the current amount of current to the base electrode of the transistor Tr via the output circuit 3. Output.

  On the other hand, when the gas heated by the heating resistor HR deviates from a certain temperature (for example, 100 ° C.), a non-zero potential difference is generated between the node A and the node B of the heater control bridge HCB. The difference potential is input to the CPU 1 via the input circuit 2. Then, the CPU 1 recognizing that the difference potential from the heater control bridge HCB is generated, outputs an output signal (control signal) to the base electrode of the transistor Tr via the output circuit 3 so that the difference potential becomes 0V. Output.

  For example, when a potential difference in a direction in which the gas heated by the heating resistor HR becomes higher than a certain temperature (for example, 100 ° C.) is generated, the CPU 1 controls the control signal so that the current flowing through the transistor Tr decreases. (Output signal) is output to the base electrode of the transistor Tr. On the other hand, when a potential difference in a direction in which the gas heated by the heating resistor HR becomes lower than a certain temperature (for example, 100 ° C.) is generated, the CPU 1 increases the current flowing through the transistor Tr. A control signal (output signal) is output to the base electrode of the transistor Tr.

  As described above, the CPU 1 performs feedback control based on the output signal from the heater control bridge HCB so that the potential difference between the node A and the node B of the heater control bridge HCB is 0 V (equilibrium state). To do. From this, it can be seen that the flow rate sensor FS in the first embodiment is controlled so that the gas warmed by the heating resistor HR has a constant temperature.

  Next, the operation | movement which measures the flow volume of the gas in the flow sensor FS in Embodiment 1 is demonstrated. First, the case of a windless state will be described. When the flow rate of the gas flowing in the direction of the arrow is zero, the upstream resistance temperature detectors UR1 and UR2 are set so that the potential difference between the node C potential and the node D potential of the temperature sensor bridge TSB becomes 0V. Each resistance value of the downstream resistance thermometers BR1 and BR2 is set.

  Specifically, the upstream resistance thermometers UR1 and UR2 and the downstream resistance thermometers BR1 and BR2 are configured to have the same distance from the heating resistor HR and the same resistance value. Therefore, in the temperature sensor bridge TSB, regardless of the amount of heat generated by the heating resistor HR, if there is no wind, the difference potential between the node C and the node D becomes 0V, and this difference potential (0V) is passed through the input circuit 2. Are input to the CPU 1. Then, the CPU 1 recognizing that the potential difference from the temperature sensor bridge TSB is 0 V recognizes that the flow rate of the gas flowing in the direction of the arrow is zero, and the gas flow rate Q is zero via the output circuit 3. Is output as an output value of the flow sensor FS.

  Next, consider the case where gas is flowing in the direction of the arrow in FIG. In this case, as shown in FIG. 1, the upstream resistance temperature detectors UR1 and UR2 arranged on the upstream side in the gas flow direction are cooled by the gas flowing in the arrow direction. For this reason, the temperature of the upstream resistance thermometers UR1 and UR2 decreases. On the other hand, the downstream resistance thermometers BR1 and BR2 arranged on the downstream side in the gas flow direction have a temperature because the gas heated by the heating resistor HR flows to the downstream resistance thermometers BR1 and BR2. Rises. As a result, the balance of the temperature sensor bridge TSB is lost, and a non-zero differential potential is generated between the node C and the node D of the temperature sensor bridge TSB.

  This difference potential is input to the CPU 1 via the input circuit 2. Then, the CPU 1 recognizing that the potential difference from the temperature sensor bridge TSB is not zero recognizes that the flow rate of the gas flowing in the arrow direction is not zero. Thereafter, the CPU 1 accesses the memory 4. Since the memory 4 stores a comparison table (table) in which the difference potential and the gas flow rate are associated with each other, the CPU 1 accessing the memory 4 calculates the gas flow rate Q from the comparison table stored in the memory 4. . Thus, the gas flow rate Q calculated by the CPU 1 is output from the flow rate sensor FS in the first embodiment via the output circuit 3. As described above, according to the flow sensor of the first embodiment, the gas flow rate can be obtained.

<Flow sensor layout configuration>
Next, the layout configuration of the flow sensor according to the first embodiment will be described. For example, the flow sensor in the first embodiment shown in FIG. 1 is formed on two semiconductor chips. Specifically, the heating resistor HR, the heater control bridge HCB, and the temperature sensor bridge TSB are formed on the first semiconductor chip CHP1 (see FIG. 3B), and the CPU 1, the input circuit 2, the output circuit 3, the memory 4, and the like Is formed in the second semiconductor chip CHP2 (see FIG. 3B). Hereinafter, a layout configuration of the first semiconductor chip CHP1 in which the heating resistor HR, the heater control bridge HCB, and the temperature sensor bridge TSB are formed will be described.

  FIG. 2 is a plan view showing a layout configuration of the first semiconductor chip CHP1 that constitutes a part of the flow sensor in the first embodiment. As shown in FIG. 2, the semiconductor chip CHP1 has a rectangular shape, and gas flows from the left side of the first semiconductor chip CHP1 to the right side (in the direction of the arrow). A rectangular diaphragm DF (see FIG. 3B) is formed on the main surface side of the rectangular first semiconductor chip CHP1. The diaphragm DF indicates a thin plate region where the thickness of the first semiconductor chip CHP1 is reduced. That is, the thickness of the region where the diaphragm DF is formed is thinner than the thickness of the other region of the first semiconductor chip CHP1.

  A flow rate detection unit FDU is formed in the surface region of the first semiconductor chip CHP1 opposite to the back surface region where the diaphragm DF is formed (see FIG. 3). A heating resistor HR is formed at the center of the flow rate detection unit FDU, and a resistor R1 that forms the heater control bridge HCB is formed around the heating resistor HR. And the resistor R2-R4 which comprises the heater control bridge HCB is formed in the outer side of the flow volume detection part FDU. A heater control bridge HCB is configured by the resistors R1 to R4 thus formed.

Since the resistor R1 constituting the heater control bridge HCB is formed in the vicinity of the heating resistor HR, the temperature of the gas warmed by the heat generated from the heating resistor HR can be accurately reflected in the resistor R1. it can.
On the other hand, since the resistors R2 to R4 constituting the heater control bridge HCB are arranged away from the heating resistor HR, they can be hardly affected by the heat generated from the heating resistor HR.
Therefore, the resistor R1 can be configured to react sensitively to the temperature of the gas heated by the heating resistor HR, and the resistors R2 to R4 are not easily affected by the heating resistor HR and have a constant resistance value. The value can be easily maintained. For this reason, the detection accuracy of the heater control bridge HCB can be increased.

Further, upstream temperature measuring resistors UR1 and UR2 and downstream temperature measuring resistors BR1 and BR2 are arranged so as to sandwich the heating resistor HR formed in the flow rate detection unit FDU. Specifically, upstream resistance thermometers UR1 and UR2 are formed on the upstream side in the arrow direction in which gas flows, and downstream resistance thermometers BR1 and BR2 are formed in the downstream in the arrow direction in which gas flows.
With this configuration, when the gas flows in the direction of the arrow, the temperature of the upstream resistance thermometers UR1 and UR2 can be lowered and the temperature of the downstream resistance thermometers BR1 and BR2 can be increased. . Thus, the temperature sensor bridge TSB is formed by the upstream resistance thermometers UR1 and UR2 and the downstream resistance thermometers BR1 and BR2 arranged in the flow rate detection unit FDU.

The heating resistor HR, the upstream resistance thermometers UR1 and UR2, and the downstream resistance thermometers BR1 and BR2 are formed by sputtering a metal film such as platinum or a semiconductor thin film such as polysilicon (polycrystalline silicon), for example. It can be formed by patterning by a method such as ion etching after forming by a method such as the CVD method or the CVD (Chemical Vapor Deposition) method.
The thus configured heating resistor HR, resistors R1 to R4 constituting the heater control bridge HCB, and upstream temperature sensing resistors UR1 and UR2 and downstream temperature sensing resistors BR1 and BR2 constituting the temperature sensor bridge TSB. Are respectively connected by the wiring WL1 and led out to the electrode pad PD1 arranged along the lower side of the first semiconductor chip CHP1.

<Structure of flow sensor>
Next, Embodiment 1 of the structure of the flow sensor FS will be described.
FIG. 3 shows Embodiment 1 of the flow sensor according to the present invention, FIG. 3 (a) is a plan view showing the structure of the flow sensor after the resin sealing step, and FIG. 3 (b) is a plan view of FIG. Is a sectional view taken along line IIIb-IIIb. 4 shows the structure of the flow sensor before the resin sealing process of the flow sensor shown in FIG. 3, FIG. 4 (a) is a plan view thereof, and FIG. 4 (b) is a plan view of FIG. 4 is a cross-sectional view taken along line IVb-IVb. Moreover, FIG. 5 is sectional drawing which shows the resin sealing process of the flow sensor in Embodiment 1 by this invention.
In the following description, the X direction, the Y direction, and the Z direction are as illustrated.
The flow sensor FS includes a lead frame LF, a first semiconductor chip CHP1 and a second semiconductor chip CHP2 mounted on the lead frame LF, an adhesive ADH1 that bonds the first semiconductor chip CHP1 to the lead frame LF, An adhesive ADH2 for bonding the semiconductor chip CHP2 to the lead frame LF and a resin MR for exposing the lead LD2 of the lead frame LF and sealing the first semiconductor chip CHP1 and the second semiconductor chip CHP2 are provided.

The lead frame LF is formed of, for example, a metal member such as copper, and a dam bar DM formed in a rectangular frame shape, and a first chip mounting that is provided inside the dam bar DM and mounts the first semiconductor chip CHP1. It has a part TAB1 (see FIG. 4A) and a second chip mounting part TAB2 (see FIG. 4A) on which the second semiconductor chip CHP2 is mounted.
The first semiconductor chip CHP1 has an upper surface (main surface), a back surface, and a peripheral side surface, and is disposed on the first chip mounting portion TAB1 with the back surface side facing the lead frame LF. As described above, the flow rate detection unit FDU including the heating resistor HR, the heater control bridge HCB, and the temperature sensor bridge TSB is formed on the main surface of the first semiconductor chip CHP1. The back surface side of the flow rate detection unit FDU of the first semiconductor chip CHP1 is removed by anisotropic etching or the like to form a recess DPR, and a thin diaphragm DF is formed on the main surface side.

  The second semiconductor chip CHP2 has an upper surface (main surface), a back surface, and a peripheral side surface, and is disposed on the second chip mounting portion TAB2 with the back surface side facing the lead frame LF. The second semiconductor chip CHP2 includes a CPU 1, an input circuit 2, an output circuit 3, a memory 4, and the like, and a control circuit unit for measuring the flow rate by controlling the flow rate detection unit FDU is formed.

  One end of the wire W1 is connected to the electrode pad PD1 of the first semiconductor chip CHP1, and the other end is connected to the lead LD1 of the lead frame LF. One end of the wire W2 is connected to the electrode pad PD2 of the second semiconductor chip CHP2, and the other end is connected to the lead LD1 of the lead frame LF. Accordingly, the electrode pad PD1 of the first semiconductor chip CHP1 and the electrode pad PD2 of the second semiconductor chip CHP2 are connected via the lead LD1. One end of the wire W3 is connected to the electrode pad PD3 of the second semiconductor chip CHP2, and the other end is connected to the lead LD2 of the lead frame LF. The wires W1, W2, and W3 are formed of gold or the like, and a wire bonding method is applied to connect the electrode pads PD1 to PD3 to the leads LD1 and LD2. When the dam bar DM of the lead frame LF is cut, the lead LD1 of the lead frame LF to which the other ends of the wires W1 and W2 are connected and the lead LD2 of the lead frame LF to which the other end of the wire W3 is connected are separated from the lead frame LF. A terminal for external connection is formed.

The back surface of the second semiconductor chip CHP2 is bonded to the upper surface of the second chip mounting portion TAB2 of the lead frame LF with an adhesive ADH2.
The back surface of the first semiconductor chip CHP1 is bonded to the upper surface of the first chip mounting portion TAB1 of the lead frame LF by an adhesive ADH1 except for the region facing the recess DPR.
As the adhesive ADH1 and the adhesive ADH2, for example, an adhesive containing a thermosetting resin such as an epoxy resin or a polyurethane resin, or an adhesive containing a thermoplastic resin such as a polyimide resin, an acrylic resin or a fluorine resin is used. can do. In addition, metallic fine particles such as gold, silver, copper, tin, etc., or inorganic fine particles containing silica, glass, carbon, mica, talc, etc. as components, mixed with thermosetting resin or thermoplastic resin as the main component. Good. By mixing an appropriate amount of metal fine particles or inorganic fine particles, the adhesive can be made conductive or the linear expansion coefficient of the adhesive can be adjusted.
Adhesives ADH1 and ADH2 may be adhesive sheets, but may be formed by application. The adhesives ADH1 and ADH2 can have any shape such as a circular shape, an elliptical shape, a rectangular shape, or a polygonal shape. In the adhesive ADH1, an opening OPA is formed in a region corresponding to the concave portion DPR formed on the back surface side of the diaphragm DF.

  As shown in FIGS. 3A and 3B, the first semiconductor chip CHP1, the second semiconductor chip CHP2, the wires W1 and W2, and the lead frame LF expose the lead LD2 of the lead frame LF. Sealed with resin MR. The resin MR is formed outside the second semiconductor chip CHP2 in the longitudinal direction (X direction) of the opening portion MROP that exposes the flow rate detection unit FDU formed on the main surface of the first semiconductor chip CHP1 and the flow rate sensor FS. It has a ventilation opening OPAV. The ventilation opening OPAV communicates with the ventilation passage LFPASS of the lead frame LF, as will be described later.

The resin MR also covers the back side of the lead frame LF, and the portion of the resin MR that covers the back side of the lead frame LF has an opening MROPr facing the opening MROP and a ventilation opening facing the ventilation opening OPAV. An opening OPAVr is formed.
As the resin MR, for example, a thermosetting resin such as an epoxy resin or a phenol resin, or a thermoplastic resin such as polycarbonate, polyethylene terephthalate, polyphenylene sulfide, or boribylene terephthalate can be used. Further, metal fine particles such as gold, silver, copper, and tin, or inorganic fine particles containing silica, glass, carbon, mica, talc, or the like as a component may be mixed. By mixing appropriate amounts of metal fine particles and inorganic fine particles, the resin MR can be made conductive, and the linear expansion coefficient of the resin MR can be adjusted.

  On the upper surface (one surface) side of the lead frame LF, as described above, the first chip mounting portion TAB1 and the second chip mounting portion TAB2 are integrally connected to the lead frame LF in a state of being connected in the longitudinal direction (X direction). Is formed. The first chip mounting portion TAB1 is formed with an opening OPCHP1 communicating with the concave portion DPR provided on the back surface side of the diaphragm DF of the first semiconductor chip CHP1. In the second chip mounting part TAB2, an opening OPCHP2 formed outside the second semiconductor chip CHP2 is formed. The opening OPCHP2 is provided at a position farthest from the opening OPCHP1 in the longitudinal direction (X direction), an inner position near the peripheral side surface of the resin MR. The lead frame LF is formed with a ventilation passage LFPASS extending in the longitudinal direction (X direction) of the flow rate sensor FS and communicating with the opening OPCHP1 on one end side and communicating with the opening OPCHP2 on the other end side. Yes. The ventilation passage LFPASS as the first embodiment is formed as a groove having an opening on the back surface (other surface) side opposite to the top surface of the lead frame LF. That is, in the lead frame LF, a plate material having a uniform thickness in which the opening portions OPCHP1 and OPCHP2 are formed is processed for thinning from the back surface side, and the first chip mounting portion TAB1 and A groove-shaped ventilation passage LFPASS is formed so that the second chip mounting portion TAB2 is formed. The thinning process may be any of press working, etching, machining and the like.

An adhesive ADH3 is provided on the back side of the lead frame LF to cover the opened surface on the back side of the ventilation passage LFPASS. Accordingly, the internal space of the recess DPR provided on the back surface side of the diaphragm DF of the first semiconductor chip CHP1 includes the opening OPCHP1, the ventilation passage LFPASS, the opening OPCHP2, and the ventilation opening OPAV of the resin MR. And communicates with the external space of the flow sensor FS.
As the material of the adhesive ADH3, the same materials as the adhesive ADH1 and the adhesive ADH2 can be used. As the adhesive ADH3, an adhesive sheet can be used, or it can be formed by coating or resin molding.
Hereinafter, the flow sensor FS before resin sealing illustrated in FIG. 4 is referred to as an unsealed flow sensor p-FS.

<Resin molding method>
Next, a method for molding the resin MR will be described with reference to FIG.
A lead frame LF is prepared in which the first chip mounting portion TAB1 and the second chip mounting portion TAB2 are integrally formed on the upper surface side, and the opening OPCHP1, the ventilation passage LFPASS, and the opening OPCHP2 are formed.
The first semiconductor chip CHP1 is bonded to the upper surface of the first chip mounting portion TAB1 of the lead frame LF with an adhesive ADH1, and the second semiconductor chip CHP2 is bonded to the upper surface of the second chip mounting portion TAB2 with an adhesive ADH2.
The electrode pad PD1 of the first semiconductor chip CHP1 and the lead LD1 of the lead frame LF are connected by a wire W1, and the electrode pad PD2 of the second semiconductor chip CHP2 and the lead LD1 of the lead frame LF are connected by a wire W2. Further, the electrode pad PD3 of the second semiconductor chip CHP2 and the lead LD2 of the lead frame LF are connected by a wire W3. Thereby, the unsealed flow rate sensor p-FS shown in FIG. 4 is produced. At this stage, the leads LD1 and LD2 are not separated from the lead frame LF.

The unsealed flow sensor p-FS is accommodated in the cavities of the upper mold UM and the lower mold BM. An elastic film LAF is installed on the inner surface of the upper mold UM. In addition, the upper mold UM is formed with an annular partition wall UMW1 surrounding the flow rate detection unit FDU and a columnar protrusion UMW2 that covers the opening OPCHP2 formed in the lead frame LF. In the lower mold BM, a raised presser portion is formed at a position facing the annular partition wall UMW1 and a position facing the protruding portion UMW2.
The partition wall UMW1 is fitted to the upper mold UM so as to be movable up and down, and the pressing force for pressing the upper surface of the first semiconductor chip CHP1 can be adjusted by a pressure adjusting mechanism (not shown). By this pressure adjusting mechanism, the pressing force applied to the first semiconductor chip CHP1 by the partition wall UMW1 is adjusted to such an extent that the first semiconductor chip CHP1 is not deformed around the diaphragm DF. The adhesive ADH1 is pressurized by pressing the first semiconductor chip CHP1 by the partition wall UMW1. The ADH 3 is pressurized between the partition wall UMW1 of the upper mold UM and the pressing part of the lower mold BM, and between the protruding part UMW2 of the upper mold UM and the pressing part of the lower mold BM.
The elastic film LAF protects the first semiconductor chip CHP1 clamped by the partition wall UMW1 of the upper mold UM and the pressing part of the lower mold BM.

  In this state, the resin material flows in from the resin inflow portion GATE and fills the cavity. At this time, since the open surface of the lower surface side of the ventilation passage LFPASS of the lead frame LF is covered with the adhesive ADH3, the resin material does not flow into the ventilation passage LFPASS. In addition, since the opening OPCHP2 of the lead frame LF is blocked by the protrusion UMW2 of the upper mold UM, the resin material does not flow into the ventilation passage LFPASS of the opening OPCHP2 from the opening OPCHP2. At this time, the dam bar DM of the lead frame LF prevents the resin material from leaking. By curing the resin material filled in the cavities of the upper mold UM and the lower mold BM, the flow sensor FS sealed with the resin MR is formed. The flow sensor FS shown in FIG. 3 in which the leads LD1 and LD2 are separated from the lead frame LF is produced by taking out the flow sensor FS from the mold and cutting the dam bar DM of the lead frame LF.

In the first embodiment, the opening exposed surface on the back side of the ventilation passage LFPASS formed in the lead frame LF is exemplified as a structure covered with the adhesive ADH3. However, the opened surface on the back side of the ventilation passage LFPASS can be directly covered with the resin MR without using the adhesive ADH3.
When the back surface of the lead frame LF is coated with the resin MR by resin molding, it is necessary to prevent the resin material before curing filled in the cavity from falling into the ventilation passage LFPASS from the opened surface. The conditions are as follows.
The inflow distance L to the groove of the Newtonian fluid is expressed by the following formula (1).
L = (ΔP × W × T ³ ) / (12 × η × Q) Formula (1)
ΔP Pressure difference, W groove width (Y direction length), T groove wall thickness, η viscosity, Q Resin material flow rate Therefore, for example, set the groove width and wall thickness small and use a resin with high viscosity In this case, the resin material does not completely fill the groove, and can be formed integrally with the lead frame on the back surface of the lead frame LF by closing the ventilation passage LFPASS.

[Contrast with conventional structure]
6 is a view showing a conventional example of a flow sensor, FIG. 6 (a) is a plan view showing a structure after a resin sealing step, and FIG. 6 (b) is a view of VIb of FIG. 6 (a). It is -VIb sectional view taken on the line.
In the flow rate sensor FSK illustrated in FIG. 6, the lead frame LFK is only formed with a through hole OP1 that penetrates the plate thickness of the lead frame LFK. That is, it does not have a configuration corresponding to the ventilation passage LFPASS and the opening OPCHP2 in the flow rate sensor FS shown as the first embodiment. Further, the resin MRK is not formed with an opening corresponding to the ventilation opening OPAV formed in the resin MR of the flow sensor FS. Other configurations are the same as those of the flow rate sensor FS shown as the embodiment, and corresponding components are denoted by the same reference numerals.

  In the conventional flow sensor FSK, an external space around the opening MROP of the resin MRK where the flow rate detection unit FDU is exposed, and an external space around the opening MROPr of the resin MRK communicating with the recess DPR through the through hole OP1. The flow sensor FSK faces the opposite side in the thickness direction (Z direction), and is almost the same in the length direction (X direction) and the width direction (Y direction).

The flow rate detection unit FDU formed on the diaphragm DF of the flow rate sensor FSK is installed in the main passage portion of the fast-flowing air in order to measure the air flow rate. In the flow sensor FSK shown in FIG. 6, the through hole OP1 communicating with the concave portion DPR directly below the diaphragm DF is exposed from the opening MROP of the resin MRK in the length direction (X direction) and the width direction (Y direction). The flow rate detection unit FDU is disposed at a position that is substantially the same as the flow rate detection unit FDU and that faces in the thickness direction (Z direction). That is, the through-hole OP1 is also installed in the main air passage portion, like the flow rate detection unit FDU. For this reason, when the air flowing through the main passage flows into the recessed portion DPR directly below the diaphragm DF through the through hole OP1, the pressure in the recessed portion DPR may greatly fluctuate. In particular, in a cold region, there is a possibility that the through-hole OP1 is blocked by freezing of moisture contained in the air.
A pressure difference between the internal space of the recess DPR and the external space around the flow rate detection unit FDU due to pressure fluctuation and freezing of moisture in the vicinity of the through-hole OP1 increases the flow measurement error.

  On the other hand, in the flow rate sensor FS shown in the first embodiment, as described above, the internal space of the recessed portion DPR on the back surface side of the diaphragm DF includes the opening portion OPCHP1, the ventilation passage LFPASS, and the opening portion OPCHP2 formed in the lead frame LF. And through the ventilation opening OPAV of the resin MR, it communicates with the external space of the flow sensor FS. The opening OPCHP2 of the lead frame LF and the ventilation opening OPAV of the resin MR are arranged at positions separated in the longitudinal direction (X direction) from the flow rate detection unit FDU arranged in the main air passage. For this reason, it is possible to prevent the pressure in the vicinity of the opening OPCHP2 from greatly fluctuating and to reduce the possibility that moisture contained in the air flows into the vicinity of the opening OPCHP2. Accordingly, the pressure difference between the internal space of the concave portion DPR directly below the diaphragm DF and the external space of the flow sensor FS can be eliminated. Accordingly, an error in flow rate measurement can be reduced, and measurement performance can be improved.

<Flow sensor device>
FIG. 7 is a cross-sectional view of Embodiment 1 of the flow sensor device according to the present invention in which the flow sensor illustrated in FIG. 3 is housed in a housing.
The flow sensor device AFS includes a flow sensor FS and a housing HOU1 that houses the flow sensor FS. The housing HOU1 is made of, for example, a thermoplastic resin such as PBT resin, ABS resin, PC resin, nylon resin, PS resin, PP resin, or fluorine resin, thermosetting resin such as epoxy resin, phenol resin, or urethane resin, or glass. It can be comprised from metal materials, such as a material, a copper alloy, an aluminum alloy, and an iron alloy.

Partition plates DPLT1 and DPLT2 that are in contact with the upper surface of the flow sensor FS are formed on the upper inner surface side of the housing HOU1, and partition plates DPLATE1 and DPLTE2 that are in contact with the lower surface of the flow sensor FS are formed on the lower inner surface side. .
The partition plate DPLT1 is disposed between the flow rate detection unit FDU of the flow rate sensor FS and the peripheral side surface on the X direction side of the first semiconductor chip CHP1, and the partition plate DPLT2 is a ventilation opening formed in the resin MR. It is arranged in the adjacent part on the X direction side of OPAV. The partition plates DPLATE1 and DPLATE2 on the lower inner surface side of the housing HOU1 are disposed at positions facing the partition plates DPLT1 and DPLT2, respectively.

  The housing HOU1 is formed with a space partitioned by the partition plates DPLT1 and DPLT2, in other words, an external communication opening OPHOU1 communicating with the opening OPCHP2 of the lead frame LF. The internal air in the concave portion DPR directly below the diaphragm DF is ventilated with the external air of the housing HOU1 through the external communication opening OPHOOU1 of the housing HOU1.

  The partition plates DPLT1 and DPLATE1 partition the main air passage portion MPASS in the vicinity of the flow rate detection unit FDU and the opening OPCHP2 of the lead frame LF. For this reason, it is possible to reliably prevent the flow of air having a large pressure fluctuation flowing through the main air passage portion MPASS from flowing into the opening OPCH2 of the lead frame LF. Further, the possibility that moisture contained in the air flows into the vicinity of the opening OPCHP2 and freezes can be reduced.

According to the said Embodiment 1, there exist the following effects.
(1) The opening OPCHP1, the ventilation passage LFPASS, and the opening OPCHP2 are formed in the lead frame LF, the ventilation opening OPAV is formed in the resin MR, and communicated with the internal space of the recess DPR on the lower side of the diaphragm DF. . Thereby, the opening OPCHP2 and the ventilation opening OPAV of the resin MR can be arranged at positions away from the flow rate detection unit FDU arranged in the main air passage. For this reason, it is possible to prevent the pressure in the vicinity of the opening OPCHP2 from fluctuating and to reduce the possibility that moisture contained in the air flows into the vicinity of the opening OPCHP2. Along with this, it is possible to eliminate the pressure difference between the internal air in the concave portion DPR directly below the diaphragm DF and the external air in the vicinity of the flow rate detection unit FDU. Accordingly, an error in flow rate measurement can be reduced, and measurement performance can be improved.

(2) A ventilation passage LFPASS communicating with the internal space of the concave portion DPR immediately below the diaphragm DF was formed in the lead frame LF. Therefore, since the members are saved as compared with the configuration in which another member is added to form the ventilation passage LFPASS, the flow sensor FS can be reduced in size and cost.

(3) The opened surface of the ventilation passage LFPASS formed in the lead frame LF was covered with the adhesive ADH3. For this reason, the flow sensor FS can be thinned.
(4) Further, if the structure that directly covers the opened surface of the ventilation passage LFPASS with the resin MR that seals the unsealed flow rate sensor p-FS without using the adhesive ADH3, the thickness is further reduced. Can be achieved. Moreover, since the operation | work which attaches adhesive agent ADH3 can be eliminated, productivity can be improved.

(5) Partition plates DPLT1 and DPLATE1 are formed in the housing HOU1 that accommodates the flow rate sensor FS and separates the main air passage portion MPASS in the vicinity of the flow rate detection unit FDU and the opening OPCHP2 of the lead frame LF. For this reason, it is possible to reliably prevent the flow of air having a large pressure fluctuation flowing through the main air passage portion MPASS from flowing into the opening portion OPCHP2 of the lead frame LF.
(6) The external communication opening OPHOU1 communicating with the opening OPCHP2 of the lead frame LF is formed in the housing HOU1 that accommodates the flow sensor FS. For this reason, the internal air of the recessed part DPR just under diaphragm DF can be ventilated with the external air of housing | casing HOU1. Thereby, the internal pressure of the concave portion DPR on the lower side of the diaphragm DF can be made the same as the external pressure of the flow sensor device AFS.

  In the first embodiment, the structure in which the opening MROPr and the ventilation opening OPAVr are formed in the portion of the resin MR that covers the back side of the lead frame LF is exemplified. However, the opening MROPr and the ventilation opening OPAVr are exemplified. May not be formed.

--Embodiment 2--
FIG. 8 shows Embodiment 2 of the flow sensor according to the present invention, FIG. 8 (a) is a cross-sectional view showing the structure before the resin sealing step, and FIG. 8 (b) is the structure after the resin sealing step. It is sectional drawing shown.
The second embodiment differs from the first embodiment in that an opening OPCHP2r is provided on the opposite side of the opening OPCHP2 formed at the other end of the ventilation passage LFPASS of the lead frame LF.
As described above, the ventilation opening OPAVr is formed in the portion of the resin MR covering the back side of the lead frame LF so as to face the ventilation opening OPAV. In the adhesive ADH3 provided on the back surface of the lead frame LF, an opening OPCHP2r penetrating in the thickness direction of the adhesive ADH3 is formed at a position facing the ventilation opening OPAVr. Therefore, the concave portion DPR provided on the back surface side of the diaphragm DF is provided for the ventilation portion provided in the opening portion OPCHP2 and the adhesive ADH3 formed on the upper surface side of the lead frame LF via the opening portion OPCHP1 and the ventilation passage LFPASS. It communicates with the opening OPAVr.
Other configurations in the second embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

According to the second embodiment, it is possible to ventilate the internal air of the concave portion DPR directly below the diaphragm DF with the external air of the flow sensor FS on both the front and back surfaces of the lead frame LF.
Therefore, the same effects as those of the first embodiment are obtained in the second embodiment.

  In the second embodiment, the opening OPCHP2 may not be formed, and only the ventilation opening OPCHP2r may be formed. That is, the lead frame LF has a structure in which the opening OPCHP2 is not formed. In this case, there is no need to form the ventilation opening OPAV in the resin MR.

--Embodiment 3--
FIG. 9 shows a third embodiment of the flow sensor according to the present invention, FIG. 9A is a cross-sectional view showing the structure before the resin sealing step, and FIG. 9B is the structure after the resin sealing step. It is sectional drawing shown.
The third embodiment is different from the second embodiment in that a plate-like structure PLT is provided on the back surface of the adhesive ADH3 provided on the back surface of the lead frame LF.
The plate-like structure PLT has a slightly larger area than the adhesive ADH3, and is disposed between the resin MR and the adhesive ADH3. The plate-like structure PLT is composed of one or a plurality of sheet-like members, and has a function of buffering external impact applied to the first semiconductor chip CHP1 and the second semiconductor chip CHP2. Further, when forming the resin MR for sealing the unsealed flow rate sensor p-FS by molding, if a material having a low melting point is used as the adhesive ADH3, the resin MR flows into the ventilation passage LFPASS. It is also possible to have a function to prevent this.

The plate-like structure PLT is, for example, a thermoplastic resin such as PBT resin, ABS resin, PC resin, nylon resin, PS resin, PP resin, or fluorine resin, or thermosetting resin such as epoxy resin, phenol resin, or urethane resin. , Glass materials, copper alloys, aluminum alloys, iron alloys and other metal materials.
Other configurations in the third embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

In the third embodiment, the same effect as in the first embodiment is obtained.
In addition, the plate-like structure PLT has an effect of buffering an external impact applied to the first semiconductor chip CHP1 and / or the second semiconductor chip CHP2.

  Note that the plate-like structure PLT need not have an area that covers the entire region of the adhesive ADH3, and may have an area corresponding to one of the first semiconductor chip CHP1 and the second semiconductor chip CHP2, or further, the opening OPCHP1. , OPCHP2 or ventilation passage LFPASS, etc. may be the corresponding area.

  In the third embodiment, similarly to the second embodiment, the adhesive ADH3 and the plate-like structure PLT are provided with ventilation openings at positions facing the openings OPCHHPr of the resin MR, and the inner space of the recess DPR is formed in the lead frame. You may make it communicate with external space of both front and back of LF.

--Embodiment 4--
FIG. 10 shows Embodiment 4 of the flow sensor according to the present invention, FIG. 10 (a) is a sectional view showing the structure before the resin sealing step, and FIG. 10 (b) shows the structure after the resin sealing step. It is sectional drawing shown.
The fourth embodiment is different from the first embodiment in that the ventilation passage LFPASS of the lead frame LF is opened on the upper surface side. The lead frame LF is formed with a ventilation passage LFPASS having an upper surface opened and a bottom LFR on the rear surface. An adhesive ADH4 is bonded to the upper surface of the lead frame LF to close the opened surface of the ventilation passage LFPASS. The adhesive ADH4 is formed with an opening OPCHP1a that opposes the concave portion DPR directly below the diaphragm DF and an opening OPCHP2a that opposes the ventilation opening OPAV of the resin MR.
Other configurations in the fourth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
In the fourth embodiment, the same effect as in the first embodiment is obtained.

In the fourth embodiment, a ventilation opening communicating with the opening OPAVr of the resin MR is formed in the bottom LFR of the lead frame LF, and the internal air in the recess DPR directly under the diaphragm DF is supplied to both front and back sides of the lead frame LF. You may be able to ventilate with outside air.
Further, the plate-like structure PLT shown in the third embodiment may be disposed between the first semiconductor chip CHP1 and / or the second semiconductor chip CHP2 and the adhesive ADH4.

--Embodiment 5--
FIG. 11 shows Embodiment 5 of the flow sensor according to the present invention, FIG. 11 (a) is a cross-sectional view showing the structure before the resin sealing step, and FIG. 11 (b) is the structure after the resin sealing step. It is sectional drawing shown.
The fifth embodiment differs from the first embodiment in that a ventilation passage LFPASS formed in the lead frame LF is penetrated in the plate thickness direction of the lead frame LF.
The ventilation passage LFPASS is formed as a through opening penetrating the plate thickness of the lead frame LF. Similar to the fourth embodiment, an adhesive ADH3f that has openings OPCHP1a and OPCHP2a and covers the opened surface on the upper side of the ventilation passage LFPASS is disposed on the upper surface of the lead frame LF. Further, as in the first embodiment, an adhesive ADH3r is disposed on the back surface of the lead frame LF so as to cover the opened surface on the back surface side of the ventilation passage LFPASS. An opening for ventilation is not formed in the adhesive ADH3r. As the adhesive ADH3r, an adhesive in which an opening OPCHP2r is formed may be used as shown in the second embodiment.
Adhesives ADH3f and ADH3r can be adhesive sheets, or can be formed by coating or resin molding.
Other configurations in the fifth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
In the fifth embodiment, the same effect as in the first embodiment is obtained.

  In the fifth embodiment, as in the third embodiment, a plate-like structure for buffering an external impact applied to the first semiconductor chip CHP1 and the second semiconductor chip CHP2 between the adhesive ADH3r and the resin MR. A body PLT may be provided.

  In the fifth embodiment, the adhesive ADH3r is not used, and the open surface on the lower surface side of the ventilation passage LFPASS may be directly covered with the resin MR. When such a structure is employed, the resin MR is molded under conditions that satisfy the formula (1).

--Embodiment 6--
FIG. 12 shows a sixth embodiment of the flow sensor according to the present invention, FIG. 12 (a) is a plan view showing the structure after the resin sealing step, and FIG. 12 (b) is an XIIb- It is XIIb sectional view taken on the line.
The difference between the sixth embodiment and the first embodiment is that the flow sensor FSB includes one semiconductor chip CHP.
Similar to the first semiconductor chip CHP1 of the first embodiment, the semiconductor chip CHP includes a flow rate detection unit FDU above the diaphragm DF. Further, the semiconductor chip CHP includes a CPU, an input circuit, an output circuit, and a memory included in the second semiconductor chip CHP2 of the first embodiment, and a control unit CU that controls the flow rate detection unit FDU. The flow rate detection unit FDU and the control unit CU are connected by a wiring WL1.

  Diaphragm DF is formed at a substantially central portion in the longitudinal direction (X direction) and width direction (Y direction) of flow sensor FSB, and a concave portion DPR is formed on the back surface side thereof. The flow rate detection unit FDU is disposed substantially at the center of the diaphragm DF. A chip mounting portion TAB is integrally formed on the upper surface of the lead frame LF. The lead frame LF is formed with a ventilation passage LFPASS having a bottom portion as a chip mounting portion TAB and an open back surface.

  The semiconductor chip CHP is bonded to the upper surface of the chip mounting portion TAB of the lead frame LF with an adhesive ADH1. In the chip mounting portion TAB of the lead frame LF, an opening OPCHP1 that connects the ventilation passage LFPASS and the concave portion DPR on the back surface side of the flow rate detection unit FDU is formed. On the back surface of the lead frame LF, an adhesive ADH3 that covers the opened surface of the lower surface of the ventilation passage LFPASS is disposed. The main surface and peripheral side surface of the semiconductor chip CHP are covered with a resin MR having an opening MROP that exposes the periphery of the flow rate detection unit FDU. An opening OPCHP2 is formed in the adhesive ADH3 at a position outside the peripheral side surface of the resin MR. The ventilation passage LFPASS extends from the opening OPCHP1 in the longitudinal direction (X direction) to the opening OPCHP2 and communicates with the opening OPCHP2.

  In the flow rate sensor FSB shown in the sixth embodiment, the internal space of the concave portion DPR immediately below the diaphragm DF communicates with the opening OPCHP2 of the adhesive ADH1 through the opening OPCHP1 of the lead frame LF and the ventilation passage LFPASS. . For this reason, the internal air of the recessed part DPR can be ventilated with the external air of the flow sensor FSB.

  As shown in FIG. 7, the flow rate sensor FSB of the sixth embodiment is housed in a housing having a partition portion that partitions the opening portion MROP of the resin MR and the opening portion OPCHP2 of the adhesive ADH3, and the flow rate sensor device. Can be formed.

Therefore, the same effects as in the first embodiment are also obtained in the sixth embodiment.
In addition, in the sixth embodiment, since the flow rate sensor FSB including one semiconductor chip CHP is obtained by integrating the control unit CU with the semiconductor chip CHP having the flow rate detection unit FDU, the flow rate sensor FSB is downsized. be able to.

  In the sixth embodiment, the ventilation passage LFPASS formed in the lead frame LF may have a structure having a bottom and a top surface of the lead frame LF opened as shown in the fourth embodiment. As shown in the fifth embodiment, the ventilation passage LFPASS formed in the lead frame LF may be a through opening that penetrates the plate thickness of the lead frame LF.

  The open surface of the ventilation passage LFPASS may be directly covered with the resin MR. An opening may be formed in the TAB of the lead frame LF so that the ventilation passage LFPASS communicates with the external space on both the front and back surfaces of the lead frame LF.

  Further, in the first to fifth embodiments, similarly to the sixth embodiment, the flow rate sensor FS including the single semiconductor chip CHP, which is integrally formed with the control unit CU that controls the flow rate detection unit FDU in the first semiconductor chip CHP1 or It can be set as the flow sensor apparatus AFS.

  In each of the above embodiments, the first and second semiconductor chips CHP1 and CHP2 and the resin MR that covers the semiconductor chip CHP have a top surface that has a flow rate detection unit for the first and second semiconductor chips CHP1 and CHP2 or the semiconductor chip CHP. The structure is illustrated as being higher than the upper surface of the FDU. However, the top surface of the resin MR has a lower structure than the top surface of the flow rate detection unit FDU of the first and second semiconductor chips CHP1 and CHP2 or the semiconductor chip CHP, or a part of the resin MR is formed of the first and second semiconductor chips. The chips CHP1 and CHP2 and the semiconductor chip CHP may not be partially covered.

  In addition, the present invention can be variously modified within the scope of the invention. In short, the present invention has a flow rate detection unit mounted on a surface of a lead frame and having a recess formed on the back surface. The lead frame includes a semiconductor chip, and the lead frame has a ventilation passage having one end connected to the recess of the semiconductor chip and the other end disposed outside the peripheral side surface of the semiconductor chip, and the other end of the ventilation passage is What is necessary is just to communicate with the ventilation opening provided in the outer side of the surrounding side surface of the semiconductor chip in resin, or to be arrange | positioned on the outer side of resin.

ADH1 to ADH3 Adhesives ADH3f, ADH3r Adhesives AFS Flow sensor device CHP Semiconductor chip CHP1 First semiconductor chip CHP2 Second semiconductor chip CU Control part DF Diaphragm DM Dam bar DPLT1, DPLT2 Partition plate DPLATE1, DPLATE2R Drain detection part DPF FS, FSB Flow sensor HCB Heater control bridge HOU1 Housing LAF Elastic film LFR Bottom LD1, LD2 Lead LF Lead frame LFPASS Ventilation passage MR Resin MROP, MROPr Opening portion MPPASS Air main passage portion OPA opening OPAV, OPAVr Ventilation opening Part OPCH1, OPCH1a Opening OPCHP2, OPCH2a Opening OPCHPr Opening OPHOU1 For external communication Mouth part PD, PD1 to PD3 Electrode pad p-FS Unsealed flow rate sensor PLT Plate-like structure TSB Temperature sensor bridge TAB Chip mounting part TAB1 First chip mounting part TAB2 Second chip mounting part UMW1 Partition wall UMW2 Protruding part W1, W2 wire WL1 wiring

Claims (15)

A lead frame,
Has a main surface, a rear surface, and a peripheral side surface, the diaphragm is formed on the main surface, a concave portion is formed on the back surface side of the diaphragm, the flow rate detecting unit before Symbol Daiyafura beam is formed, the lead frame a first semiconductor chip mounted on one surface of,
A resin that exposes the flow rate detection unit and covers at least a part of the main surface or the peripheral side surface of the first semiconductor chip;
The lead frame has one end communicating with the recess of the first semiconductor chip, a ventilation passage and a second end disposed outside of said peripheral surface of said first semiconductor chip,
The ventilation passage has an opening that opens on one side of the lead frame on which the first semiconductor chip is mounted, and a bottom formed integrally with the lead frame on the other side opposite to the one side. Having a groove,
At least a part of the opening is provided with an adhesive,
The other end of the ventilation passage of the lead frame communicates with a ventilation opening provided on the outside of the peripheral side surface of the one semiconductor chip in the resin, or is disposed on the outside of the resin .
A flow rate sensor , wherein a second semiconductor chip is between the first semiconductor chip and the ventilation opening . The flow sensor according to claim 1,
Furthermore, the semiconductor chip is provided with a semiconductor chip different from the semiconductor chip, and the another semiconductor chip has a main surface, a back surface, a peripheral side surface, and a control unit that controls the flow rate detection unit, and the semiconductor chip is mounted A flow rate sensor disposed on the same surface side of the lead frame, wherein at least a part of the main surface and the peripheral side surface of the another semiconductor chip is covered with the resin. The flow sensor according to claim 1 or 2,
The ventilation passage of the lead frame is a groove in which a side opposite to the one surface on which the semiconductor chip is mounted is opened, and a chip mounting portion on which the semiconductor chip is mounted is integrally formed on the one surface side. There is a flow sensor. The flow sensor according to claim 3,
The flow sensor, wherein an opening for communicating the groove of the lead frame and the recess of the semiconductor chip is formed in the chip mounting portion of the lead frame. The flow sensor according to claim 3,
Furthermore, the flow sensor provided with the lower side cover member which covers the said groove | channel of the said lead frame. The flow sensor according to claim 5, wherein
The flow rate sensor, wherein the lower side covering member is an adhesive. The flow sensor according to claim 6, wherein
The flow sensor further comprises a plate-like structure disposed on a surface of the adhesive opposite to the lead frame bonding surface. The flow sensor according to claim 1 or 2,
The ventilation passage of the lead frame is a groove having an opening formed on the one surface side where the semiconductor chip is mounted and a bottom portion formed integrally with the lead frame on the other surface opposite to the one surface. Flow sensor. The flow sensor according to claim 8,
Furthermore, the flow sensor provided with the upper side cover member which covers the said lead frame. The flow sensor according to claim 9,
The flow rate sensor, wherein the upper side covering member is an adhesive. The flow sensor according to claim 1 or 2,
The ventilation passage of the lead frame is an opening that penetrates the lead frame in the thickness direction, and includes an upper side covering member that covers an upper surface side of the opening and a lower side covering member that covers a lower surface side of the opening. , Flow sensor. The flow sensor according to claim 1 or 2,
The resin has an other surface covering portion that covers the other surface opposite to the one surface of the lead frame, and the other end of the ventilation passage of the lead frame is disposed outside the other surface covering portion. A flow sensor. The flow sensor according to claim 1,
At least one of the one surface of the lead frame and the other surface facing the one surface is opened in the ventilation passage of the lead frame, and the opened surface of the ventilation passage is directly made of the resin. Covered flow sensor. A flow sensor according to any one of claims 1 to 13,
A housing that houses the flow sensor,
The housing includes a partition unit that partitions a region where the flow rate detection unit of the semiconductor chip is exposed from the resin and a region where the other end of the ventilation passage of the lead frame is disposed. apparatus. The flow sensor device according to claim 14,
The housing has a flow sensor device having an external communication opening that communicates an area where the other end of the ventilation passage of the lead frame is disposed to the outside of the housing.

Images