JPH05142008A - Sensor device - Google Patents

Abstract

PURPOSE:To improve precision in positioning a sensor element in a measuring atmosphere and also to prevent turbulence of the measuring atmosphere in measurement and thereby to improve measuring precision. CONSTITUTION:A recessed part 3 in which a flow rate sensor chip 2 is fitted is formed in a base plate 1, with the depth of the recessed part 3 set to be equal to the thickness of the flow rate sensor chip 2, so that the two diagonal lines of the recessed part 3 are parallel and perpendicular to the edge side parts of the base plate 1. On the occasion when a flow rate sensor 6 having the flow rate sensor chip 2 fitted in the recessed part 3 of the base plate 1 is fitted to a fluid passage part, according to this constitution, the flow rate sensor chip 2 can be positioned at a prescribed position at which the precision in measurement of a flow rate is excellent in respect to the flowing direction of a fluid to be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor device, and more particularly to a sensor device suitable for use in improving positioning accuracy and measurement accuracy of a sensor element in a measurement atmosphere.

[0002]

2. Description of the Related Art Conventionally, a flow sensor chip is mounted on the upper surface of a substrate with, for example, an adhesive, and pins, partitions, covers, etc. are mounted around the flow sensor chip to prevent disturbance of the flow path of the fluid to be measured. A flow sensor having a different structure is known. As this type of flow rate sensor, for example, Japanese Patent Laid-Open No. Hei 3
The one described in JP-A-53170 is proposed.

[0003]

However, the above-mentioned conventional technique has the following problems. Since the conventional flow rate sensor has a structure in which the flow rate sensor chip is simply attached to the upper surface of the substrate with an adhesive or the like, a convex portion corresponding to the thickness of the flow rate sensor chip is formed on the upper surface of the substrate, and the fluid to be measured is Is disturbed by the convex portion due to the thickness of the flow rate sensor chip protruding on the upper surface of the substrate, resulting in the problem that the measurement accuracy of the flow rate is not stable. Further, it is necessary to accurately position the flow rate sensor chip in the flow direction of the fluid to be measured, but since the flow rate sensor chip is mounted on a flat substrate, the positioning accuracy is poor and a flow rate measurement error occurs. There was a problem.

The present invention effectively solves the above-mentioned problems, and a sensor that achieves an improvement in the positioning accuracy of a sensor element in a measurement atmosphere and an improvement in measurement accuracy by preventing disturbance of the measurement atmosphere during measurement. The purpose is to provide a device.

[0005]

In order to achieve the above-mentioned object, the present invention provides a sensor device in which a semiconductor sensor element for measuring a physical quantity is provided on a substrate and arranged in a measurement atmosphere with directivity. And a substrate arranged to have a directivity in a measurement atmosphere, and a positioning portion arranged on the substrate for positioning two adjacent sides of the semiconductor sensor element with respect to the substrate. It is characterized by doing.

[0006]

According to the sensor device of the present invention, the positioning portion for positioning the two adjacent sides of the semiconductor sensor element is arranged on the substrate arranged in the measurement atmosphere with directivity. The semiconductor sensor element can be arranged at an accurate measurement position in the predetermined direction of the measurement atmosphere. As a result, it is possible to eliminate the problem that a measurement error occurs in the measurement atmosphere due to the poor positioning accuracy of the sensor element, as in the conventional case where the sensor chip is simply mounted on the upper surface of a flat substrate. Further, by disposing the semiconductor sensor element in the positioning portion of the substrate so that the element surface does not have a step with the substrate surface, the measurement atmosphere can be accurately measured without disturbing the measurement atmosphere. As a result, it is possible to surely prevent the phenomenon that the measurement atmosphere is disturbed by the convex portion due to the thickness of the sensor element protruding to the upper surface of the substrate as in the related art, and it is possible to solve the problem that the measurement accuracy is not stable.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the sensor device of the present invention is applied to a flow rate sensor will be described below with reference to the drawings. 1 and 2 are a plan view and a side sectional view of a flow sensor according to the present embodiment. For example, a rectangular flow sensor chip 2 is mounted near the center of a substrate 1 made of ceramic or the like. A concave portion 3 having a shape is formed, and both diagonal lines of the concave portion 3 and each edge portion of the substrate 1 are set to be in parallel and at right angles. Further, the planar shape of the recess 3 is set to a size such that the flow rate sensor chip 2 can be mounted with a slight gap. Further, the depth of the concave portion 3 is such a depth that does not cause a step between the substrate surface and the flow sensor chip surface when the flow sensor chip 2 is mounted in the concave portion 3,
Alternatively, the step between the surface of the substrate and the surface of the flow rate sensor chip is processed to a depth such that the flow rate sensor has optimum flow rate measurement accuracy. That is, by forming the recess 3 formed in the substrate 1 into the above structure, the substrate 1
When the flow rate sensor including the flow rate sensor chip 2 and the flow rate sensor chip 2 is attached to the fluid passage portion (described later), the flow rate sensor chip 2 has a predetermined position (the flow rate measurement accuracy is good) with respect to the flow direction of the fluid to be measured (the arrow direction in the drawing) Position).

When the flow sensor chip 2 is mounted in the concave portion 3, as shown in FIG.
Of the flow sensor chip 2 and the power supply terminal (not shown) and the vicinity of the recess 3 of the substrate 1 after the two adjacent sides of the recess 3 are closely attached to the adjacent two sides of the recess 3. The plurality of electrode pads 4A arranged in the above are connected by wires 4B. As a result, the flow sensor chip 2 can be accurately positioned with respect to the substrate 1 simply by closely attaching the two adjacent sides of the flow sensor chip 2 to the two adjacent sides of the recess 3. ..
That is, if the substrate 1 is attached to a predetermined location of the fluid passage portion (described later), the flow rate sensor chip 2 can be accurately positioned in the flow direction of the fluid to be measured. Further, at the end of the substrate 1, for example, six connection terminals 5 for connecting to an external circuit (not shown) for driving the flow rate sensor.
And a conductor (not shown) is formed between each connection terminal 5 and each electrode pad 4A by, for example, thick film printing. The substrate 1 and the flow rate sensor chip 2 form a flow rate sensor 6.

Here, in the case of manufacturing the flow sensor chip 2 of this embodiment, as shown in FIG. 3, for example, a semiconductor substrate 7 made of silicon or the like is divided into a large number of element regions 8 by element isolation grooves 9. By forming the element patterns of the heater, the temperature-sensitive resistor, etc. on these element regions 8 by bending the element regions 8 along the element isolation grooves 9, The flow sensor chip 2 is obtained. The structure and characteristics of the flow rate sensor chip 2 manufactured as described above will be described. On the surface of the bridging portion 10 formed in the element region 8 in a thermally insulating state, a thin film sandwiched by a protective film (not shown) is formed. Heater 11
And thin-film temperature-sensitive resistors 12A, 12 sandwiching the heater 11.
B is formed, and a thin film ambient temperature sensitive resistor 1 is formed at the corner of the substrate.
2C is formed. When the fluid to be measured flows in the direction of the arrow in the figure, the temperature-sensitive resistor 12A on the upstream side is cooled,
The temperature-sensitive resistors 12B on the downstream side are heated by the heater 11 using the fluid flow as a medium, so that both temperature-sensitive resistors 1
Since a temperature difference occurs between 2A and 12B, if the temperature difference is converted into a voltage by the bridge circuit, a voltage output according to the flow rate can be obtained, and the flow rate is measured based on the voltage output.

Further, the circuit configuration of the flow sensor 6 is shown in FIG.
It is as shown in. That is, elements Ru, Rd, RX, RY, RZ, and RH surrounded by ellipses in the figure are elements formed on the semiconductor substrate 7 serving as the base of the flow sensor chip 2, and Ru and Rd are temperature sensitive resistors. , RH are heaters. The elements R1 and R2 are elements formed on the ceramic substrate 1 on which the flow rate sensor chip 2 is mounted, and the elements Ru to RH and the elements R1 and R2 are connected via the electrode pads 4A and the wires 4B described above. Has been done. An external circuit (sensing bridge) that measures the flow rate by detecting the temperature difference between the temperature sensitive resistors Ru and Rd associated with the flow of the fluid as a voltage in the pin number of the six connection terminals 5 described above. ) 13 is connected, an external circuit (heater control) is connected to, and is grounded.

Next, the operation of the flow rate sensor of this embodiment constructed as described above will be described. First, as shown in FIG. 1 above, the flow rate sensor 6 having the flow rate sensor chip 2 positioned and fixed inside the concave portion 3 of the substrate 1 is installed inside the case 15A of the fluid passage portion 15 as shown in FIGS. Then, the flow sensor 6 is attached to the fluid passage portion 15 by attaching the lid 15B of the fluid passage portion 15 to the case 15A. By mounting the flow rate sensor 6 on the fluid passage portion 15 as described above, the flow rate sensor chip 2 positioned and fixed inside the recess 3 of the substrate 1 flows to a position facing the passage 15C of the fluid passage portion 15 and flows. It is arranged so as not to project into the path 15C. After that, when a fluid is caused to flow in the direction of the arrow in FIG. 5 to flow in from the inlet of the fluid passage portion 15, the fluid flows inside the flow channel 15C and flows out from the outlet. When the fluid flows on the surface of the flow rate sensor chip 2 which faces the flow passage 15C of the fluid passage portion 15, as shown in FIG.
Is cooled and the temperature-sensitive resistor 12B on the downstream side is heated by the heater 11 using the fluid flow as a medium, so that a temperature difference occurs between the temperature-sensitive resistors 12A and 12B, resulting in the sensing bridge 13 (see FIG. 4). ) Is used to measure the flow rate by converting the temperature difference into a voltage.

By the way, as described above, the concave portion 3 in which the flow sensor chip 2 of the flow sensor 6 is mounted is set so that the diagonal line of the concave portion 3 and each edge portion of the substrate 1 are parallel and at right angles. Since the flow sensor chip 2 is
Therefore, the flow rate sensor chip 2 can be positioned at an accurate measurement position with respect to the fluid to be measured. As a result, as in the case where the flow sensor chip is simply mounted on the upper surface of the flat substrate as in the conventional case,
It is possible to solve the problem that a flow rate measurement error occurs due to poor positioning accuracy of the flow rate sensor chip. Also,
The flow sensor chip 2 of the flow sensor 6 includes the fluid passage portion 15
Since it is arranged so as to face the flow channel 15C and not protrude into the flow channel 15C, the flow rate can be accurately measured without disturbing the flow of the fluid in the flow channel 15C.
As a result, it is possible to reliably prevent the phenomenon in which the fluid to be measured is disturbed by the convex portion due to the thickness of the flow rate sensor chip protruding to the upper surface of the substrate as in the past, and solve the problem that the measurement accuracy of the flow rate is not stable. You can

The present invention has modifications of the following items. In the above-mentioned embodiment, the concave portion 3 is formed by scraping the surface of the substrate 1, but the present invention is not limited to this. It is also possible to form a hole having a shape parallel to the edge portion of the plate, and to bond the plate having the flow rate sensor chip 2 mounted thereto to another flat plate. Although the substrate 1 and the flow sensor chip 2 are electrically connected to each other via the electrode pads 4A and the wires 4B in the above-described embodiment, the present invention is not limited to this, and the surface of the substrate 1 and the surface of the flow sensor chip 2 are not limited thereto. By utilizing the fact that there is no step between the substrate and the flow sensor, it is possible to electrically connect the substrate 1 and the flow sensor chip 2 through a metal plate or a metal foil. In the above embodiment, the case where the sensor device of the present invention is applied to the flow rate sensor has been described, but the present invention is not limited to this.
It can also be applied to a pressure sensor. In the above-mentioned embodiment, the substrate on which the sensor chip is mounted has a rectangular shape, but the present invention is not limited to this. For example, the circular package 20 having the structure shown in FIG. 7 or the circular package 21 having the structure shown in FIG. 8 is used. It is also possible. Figure 7
The package 20 is provided with a protrusion 22a for mounting the package 20 in a measuring atmosphere with directivity (for example, in a predetermined direction of the flow path).
A plurality of pins 23 that are wire-bonded to electrode pads (not shown) are provided on a metal package body 22 provided with, and each pin 23 and the package body 22 are mutually connected inside the package by an insulator 24. Insulated,
A hermetically sealed lead wire 25 is attached to each pin 23, and at least three positioning projections 26 for positioning the sensor element S are provided in the central portion of the package body 22. When the sensor element S is mounted on the package body 22, the sensor element S
The sensor element S can be accurately positioned with respect to the package body 22 by abutting the adjacent two sides of the three positioning projections 26 and adhering them with an adhesive or the like. Therefore, the package 2 in which the sensor element S is mounted
It is possible to accurately position the sensor element S with respect to the flow path by mounting 0 on the predetermined position of the flow path to be measured in the flow rate measuring device via the protrusion 22a. On the other hand, the package 21 of FIG. 8 has the same structure as the package 20 of FIG. 7 except for the sensor element mounting portion. That is, in the package 21 of FIG. 8, as the sensor element mounting portion, a rectangular positioning recess 2 having a shape capable of mounting the sensor element in the central portion of the package body 27.
8 is provided. 7 and 8 are denoted by the same reference numerals, and the description thereof will be omitted. The package body 2
When the sensor element is mounted on 7, the sensor element is attached to the package main body 27 by abutting the two adjacent sides of the sensor element to the two adjacent sides of the positioning recess 28 and adhering them with an adhesive or the like. It can be accurately positioned with respect to each other. Therefore, the package 21 equipped with the sensor element
The sensor element can be accurately positioned with respect to the flow path by mounting the sensor element on a predetermined position of the flow path to be measured in the flow rate measuring device via the protrusion 27a.

[0014]

As described above, according to the present invention, there is provided a sensor device having a semiconductor sensor element for measuring a physical quantity on a substrate and having a directivity in a measurement atmosphere. It is configured to include a substrate that is directionally arranged in a measurement atmosphere, and a positioning portion that is arranged on the substrate and positions two adjacent sides of the semiconductor sensor element with respect to the substrate. Therefore, the effects of the following items can be achieved. On a substrate that is arranged with directionality in the measurement atmosphere,
Since the positioning portion for positioning the two adjacent sides of the semiconductor sensor element is provided, the semiconductor sensor element can be placed at an appropriate measurement position in the predetermined direction of the measurement atmosphere. As a result, it is possible to eliminate the problem that a measurement error occurs in the measurement atmosphere due to the poor positioning accuracy of the sensor element as in the conventional case where the sensor element is simply mounted on the upper surface of a flat substrate. Further, if the semiconductor sensor element is arranged in the positioning portion of the substrate so that the element surface does not have a step with the substrate surface,
The measurement atmosphere can be accurately measured without disturbing the measurement atmosphere. As a result, it is possible to surely prevent the phenomenon that the measurement atmosphere is disturbed by the convex portion due to the thickness of the sensor element protruding to the upper surface of the substrate as in the related art, and it is possible to solve the problem that the measurement accuracy is not stable.

[Brief description of drawings]

FIG. 1 is a plan view of a flow sensor according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a flow sensor according to the present embodiment.

FIG. 3 is an external view of a silicon substrate on which a flow sensor chip of this embodiment is formed.

FIG. 4 is a circuit configuration diagram of a flow rate sensor of the present embodiment.

FIG. 5 is a front view when the flow rate sensor of the present embodiment is arranged in a fluid passage portion.

FIG. 6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is an external view of a modified sensor chip mounting package.

FIG. 8 is an external view of a sensor chip mounting package of another modification.

[Explanation of symbols]

 1 substrate 2 flow rate sensor chip (semiconductor sensor element) 3 recess (positioning part) 6 flow rate sensor (sensor device) 15 fluid passage part 20, 21 package (board) 26 positioning protrusion (positioning part) 28 positioning recess (positioning part) ) S sensor element (semiconductor sensor element)

Claims (1)

[Claims] 1. A sensor device comprising a semiconductor sensor element for measuring a physical quantity on a substrate and arranged in a measurement atmosphere with directivity, wherein the sensor device is arranged with directionality in the measurement atmosphere. And a positioning portion which is disposed on the substrate and positions two adjacent sides of the semiconductor sensor element with respect to the substrate.