JP3500825B2 - pressure sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a pressure sensor that converts an electric signal.

[0002]

2. Description of the Related Art Conventionally, there has been a pressure sensor that converts pressure into an electric signal using a piezoresistive element or the like.
As shown in (a) and (b), a sensor body 1, a recess 12 provided on the surface of the sensor body 1, and a sensor chip having a diaphragm structure arranged on the bottom of the recess 12 via a pedestal 6. 4a, a pressure introducing port 14 formed in the sensor body 1 for introducing pressure into the recess 4b formed in the lower surface of the sensor chip 4a, a lead 9 provided by simultaneous molding with the sensor body 1, and a sensor chip. 4a and the wire 5 wire-bonded to the lead 9. Further, in this pressure sensor, in order to protect the contact point between the sensor chip 4a and the wire 5, silicon 7 is applied and cured on the surface of the sensor chip 4a. In this pressure sensor, a pressure detecting element is formed on the surface of the sensor chip 4a, and the pressure difference between the upper and lower surfaces of the sensor chip 4a is detected.

Further, as shown in FIGS. 7 (a) and 7 (b), a sensor body 1 having leads 9 formed by simultaneous molding, a recess 12 provided on the surface of the sensor body 1, and a bottom of the recess 12 are provided. A sensor chip 4a having a diaphragm structure, which is disposed on the base via a pedestal 6 and has a pressure detecting element formed on the surface,
A wire 5 connecting the sensor chip 4a and the lead 9
There is also a pressure sensor composed of the silicon 7 dropped in the recess 12. A recess 4b is provided on the lower surface of the sensor chip 4a, and the sensor chip 4a has a recess 1
The absolute pressure introduced from 2 is detected.

[0004]

In the pressure sensor having the above-mentioned structure, since the leads formed at the same time are bent and mounted on the sensor body, it is necessary to provide a clearance necessary for bending the leads. There is a problem that there is a limit to the reduction of mounting area. The present invention has been made in view of the above problems, and an object of the present invention is to provide a pressure sensor that is downsized and has a small mounting area.

It is an object of the invention of claim 2 to provide a pressure sensor which is downsized and prevents the sensor chip from being sealed. An object of the invention of claim 3 is to provide a pressure sensor which can be downsized and whose mounting surface can be selected. It is an object of the invention of claim 4 to provide a pressure sensor which is downsized and has improved workability during soldering and mounting.

An object of the invention of claim 5 is to provide a pressure sensor for absolute pressure detection which is downsized and has a small mounting area.

[0007]

According to a first aspect of the present invention, a sensor chip is formed on a surface of a three-dimensional circuit board.
A recess for mounting is formed and the inside of the recess is formed.
Slope for wiring having a slope of approximately 60 degrees or more and less than 90 degrees on the surface
It is equipped with a sensor body with a surface
The first electrode is formed on the surface and the first electrode is electrically connected.
A second electrode that is electrically connected to the back of the sensor body
And electrically connect the first electrode and the sensor chip.
Form a wiring pattern that runs through at least the slope
Since it is, it is possible to form a wiring pattern on a slope by using the exposure method or a laser method.

According to a second aspect of the invention, in the first aspect of the invention, a stepped portion for mounting a lid covering the recess is formed in the recess,
By forming the slope deeper than the stepped part, a gap for preventing the recess from being sealed is formed between the slope and the stepped part, so the recess is sealed with a simple structure. it can. According to the invention of claim 3, in the invention of claim 1, since the bonding areas of the respective electrodes provided on the front and back surfaces of the sensor body are made equal, whichever surface of the electrodes is used to bond the sensor body. , The same adhesive strength can be obtained.

According to the invention of claim 4, in the invention of claim 1, since the positioning protrusion is formed on the sensor body, the position of the sensor body can be easily determined. According to the invention of claim 5, the three-dimensional three-dimensional circuit board is used.
A recess is formed on the surface for mounting the sensor chip.
And the inner surface of the recess is approximately 60 degrees or more and 90 degrees or more.
Formed with a slope for wiring with a slope less than
It has a main body, and the first electrode is formed on the surface of the sensor main body.
And a second electrode electrically connected to the first electrode.
A pole is formed on the back surface of the sensor body, and the first electrode and the sensor
-Use fewer wiring patterns to electrically connect the chip.
Since it is formed so as to pass through at least the slope and the recess is used as the pressure receiving surface, the wiring pattern can be formed on the slope by using the exposure method or the laser method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG.
As shown in (a) to (c), the sensor body 1 formed as a three-dimensional circuit board, the recess 12 provided on the surface of the sensor body 1, and the pedestal 6 at the bottom of the recess 12 are interposed. A sensor chip 4a of a diaphragm structure which is arranged and has a pressure detecting element such as a piezoresistive element formed on its surface;
A first electrode 2a formed on the surface of the sensor body 1,
A second electrode 2b formed on the back surface of the sensor body 1,
The pressure introducing port 14 provided on the back surface of the sensor body 1 for introducing pressure to the concave portion 4b formed on the lower surface of the sensor chip 4a and the inclination of, for example, 60 degrees formed on both side surfaces of the concave portion 12 are formed. The inclined surface 11 and the wiring pattern 17 formed on the inclined surface 11 by using the laser method or the exposure method in order to route the wiring from the first electrode 2a to the sensor chip 4a.
A wire 5 wire-bonded to connect the sensor chip 4a and the wiring pattern 17, and a silicon 7 formed on the surface of the sensor chip 4a to protect the contact point between the sensor chip 4a and the wire 5. The first and second electrodes 2 are composed of a stepped portion 13 formed in the middle step of the slope 11 and a lid 3 disposed on the stepped portion 13.
A and 2b are connected by a wiring (not shown) formed on the outer surface of the sensor body 1. Further, in the stepped portion 13 provided for disposing the lid 3, the slope 11 is dug deeper than the stepped portion 13, and a gap 18 is formed between the slope 11 and the stepped portion 13. Since it is formed, the sensor chip 4 provided in the recess 12 even after the lid 3 is provided.
a is not sealed from the outside. Here, the sensor chip 4a having a pressure detection element formed on the surface detects the pressure difference between the pressure of the concave portion 4b provided on the lower surface and the pressure of the upper surface.

By the way, in the pressure sensor of this embodiment, the sensor main body 1 is formed as a three-dimensional molded circuit board, and when the wiring pattern 17 is formed by the exposure method, it is resin-molded. Gold plating is performed on the entire surface of the sensor body 1 to prepare a gold resist. Next, as shown in FIG. 4, the pattern 81 printed on the photomask 8 is exposed to produce a desired resist pattern, and is formed on the slope 11 of the sensor body 1 having a slope of 60 degrees, for example. The wiring pattern 17 is produced.

The wiring pattern 17 is formed by using the laser method.
In the case of manufacturing the above, first, the entire surface of the resin-molded case body 1 is plated with copper, and as shown in FIG. 5, the copper is removed by irradiating the laser beam 10, and the desired wiring pattern 17 is formed on the sensor body. It is formed on the inclined surface 11 of 60 degrees, which is formed on No. 1. Here, the slope of the slope 11 is
The inclination is set to approximately 60 degrees or more and less than 90 degrees so that the wiring pattern 17 can be formed by using the exposure method or the laser method and the size of the sensor body 1 can be reduced.

As described above, since the wiring pattern 17 is formed on the inclined surface 11 of the case body 1 by using the exposure method or the laser method, it is not necessary to simultaneously form the wiring lead with the sensor body 1. Therefore, it is not necessary to secure a clearance for bending the lead, and the pressure sensor can be downsized and the mounting area can be reduced. (Embodiment 2) The pressure sensor of this embodiment is similar to that shown in FIG.
As shown in (a) to (c), a sensor body 1 formed as a three-dimensional circuit board, a recess 12 formed on the surface of the sensor body 1, and a pedestal 6 at the bottom of the recess 12 are interposed. Sensor chip 4a having a diaphragm structure
A pressure introducing port 14 formed on the back surface of the sensor body 1 for introducing pressure into the recess 4b on the lower surface of the sensor chip 4a; and the first electrodes 2a formed on both sides of the recess 12 on the surface of the sensor body 1. And the second electrodes 2b formed on both sides of the pressure introducing port 14 on the back surface of the sensor body 1, and the first and second electrodes 2 penetrating the inside of the sensor body 1.
Through hole 16 connecting a and 2b, positioning projection 15 formed on the surface of sensor body 1, and recess 1
For example, slopes 11 having a slope of 60 degrees formed on both side surfaces of 2
A wiring pattern 17 formed on the sloped surface 11 by a laser method or an exposure method in order to route the wiring from the first electrode 2a to the sensor chip 4a;
Wire 5 for connecting the wiring pattern 17 to the wiring pattern 17, the sensor chip 4a and the wire 5
Silicon 7 formed on the surface of the sensor chip 4a to protect the contact point with the stepped portion 13 formed in the middle step of the slope 11, and a gap provided between the slope 11 and the stepped portion 13. It is composed of 18 and.

Since the contact areas of the first and second electrodes 2a and 2b are equal, the sensor body 1
Even when the first electrode 2a is used as the mounting surface for mounting the surface, the same strength as when the second electrode 2b is used for mounting can be obtained. You can also do it. Further, since the positioning pin 15 is formed on the surface of the sensor body 1,
Positioning can be easily performed when performing reflow soldering on the sensor chip 4a or mounting the sensor body 1.

Since the structure of the sensor chip 4a and the method of manufacturing the wiring pattern 17 are the same as those in the first embodiment, the description thereof will be omitted. (Embodiment 3) The pressure sensor of this embodiment is similar to that shown in FIG.
As shown in (a) to (d), the sensor body 1 formed as a three-dimensional circuit board, the recess 12 formed on the surface of the sensor body 1, and the recess 1 on the surface of the sensor body 1
A first electrode 2a formed on both sides of the sensor body 2, a second electrode 2b formed on the back surface of the sensor body 1, and first and second electrodes 2a and 2b formed on the outer surface of the sensor body 1. Wiring (not shown) for connecting the pedestal 6 and the pedestal 6 at the bottom of the recess 12.
A sensor chip 4a disposed through the inner surface of the recess 12 and a slope 11 formed on the inner surface of the recess 12 with a slope of, for example, 60 degrees,
The inclined surface 11 is composed of a wiring pattern 17 formed by an exposure method or a laser method, and silicon 7 dropped in the recess 11.

In the pressure sensor of this embodiment, the opening of the recess 12 provided in the sensor body 1 serves as a pressure receiving surface, and the sensor chip 4a having a pressure detecting element such as a piezoresistive element formed on the surface is provided. The absolute pressure introduced from the recess 12 is detected. Since the structure of the sensor chip 4a and the method of manufacturing the wiring pattern 17 are the same as those in the first embodiment, the description thereof will be omitted.

[0017]

As described above, according to the invention of claim 1 , the sensor chip is mounted on the surface of the three-dimensional circuit board.
A recess for forming is formed and the inner surface of the recess is formed.
Slope for wiring having a slope of approximately 60 degrees or more and less than 90 degrees
The surface of the sensor body
Forming a first electrode on the
Form the second electrode on the back of the sensor body
And electrically connect the first electrode and the sensor chip.
Form a wiring pattern that runs through at least the slope
Since the wiring pattern can be formed on the slope using the exposure method or the laser beam, there is an effect that the lead for wiring is unnecessary, and the sensor body can be downsized and the mounting area can be reduced.

According to the second aspect of the present invention, the stepped portion on which the lid for covering the recess is placed is formed in the recess, and the slope is formed deeper than the stepped portion, so that the slope between the slope and the stepped portion is formed. Since a gap for preventing the recess from being sealed is formed in the recess, it is possible to prevent the recess from being sealed with a simple structure, so it is possible to reliably prevent the sensor chip provided in the recess from being sealed. effective.

According to a third aspect of the present invention, the bonding areas of the electrodes provided on both the front and back surfaces of the sensor body are equal, and even if the sensor body is bonded with any of the mounting surfaces as the mounting surface, the same bonding strength is obtained. Since it can be obtained, there is an effect that it is possible to provide a pressure sensor whose mounting surface can be selected. According to the invention of claim 4, since the positioning protrusion is formed on the sensor main body and the position of the sensor main body can be easily determined, the workability at the time of reflow soldering and mounting of the sensor main body is improved. There is.

The invention of claim 5 is a three-dimensional circuit board.
Consisting of a recess for mounting the sensor chip on the surface
Is formed, and the inner surface of the recess is approximately 60 degrees or more.
A cell having a slope for wiring having a slope of less than 90 degrees is formed.
Sensor body with the first electrode on the surface of the sensor body
Formed and electrically connected to the first electrode
The second electrode is formed on the back surface of the sensor body, and the first electrode
Wiring pattern that electrically connects to the sensor chip
Is formed so as to pass through at least the slope, the recess is used as the pressure receiving surface, and the wiring pattern can be formed on the slope by using the exposure method or the laser beam, so that the lead for wiring is not required, and the sensor body is downsized, There is an effect that it is possible to provide a pressure sensor for absolute pressure detection, which achieves a reduction in mounting area.

[Brief description of drawings]

1A and 1B show a pressure sensor of Embodiment 1, where FIG. 1A is a top view, FIG. 1B is a cross-sectional view, and FIG.

2A and 2B show a pressure sensor of Embodiment 2, where FIG. 2A is a top view, FIG. 2B is a cross-sectional view, and FIG.

3A and 3B show a pressure sensor of Embodiment 3, where FIG. 3A is a top view, FIG. 3B is a cross-sectional view, FIG. 3C is a bottom view, and FIG.

FIG. 4 is a partially omitted external perspective view showing a method for manufacturing the above slope.

FIG. 5 is a partially omitted external perspective view showing another method of manufacturing the above slope.

FIG. 6 shows a conventional pressure sensor, (a) is a plan view,
(B) is a sectional view.

FIG. 7 shows another conventional pressure sensor, (a) is a plan view and (b) is a cross-sectional view.

[Explanation of symbols]

1 sensor body 2a First electrode 2b Second electrode 4a sensor chip 4b recess 5 wires 11 slopes 12 recess 14 Pressure inlet 17 Wiring pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 6-283805 (JP, A) Fukukaihei 5-1270 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01L 7/00-23/00 H01L 23/28-23/30 H05K 3/18

Claims (5)

(57) [Claims] 1. A three-dimensional circuit board comprising a three-dimensional circuit board and a sensor on the surface.
A recess for mounting the sir chip is formed
In addition, the inner surface of the recess has a slope of approximately 60 degrees or more and less than 90 degrees.
It has a sensor main body with a slope for wiring that has,
Forming a first electrode on the surface of the sensor body
A second electrode electrically connected to the first electrode
It is formed on the back surface of the sensor body, and the first electrode and the front
Wiring pattern to electrically connect with the sensor chip
A pressure sensor formed so as to pass through at least the slope . 2. A stepped portion on which a lid for covering the recess is placed is formed in the recess, and the slope is formed deeper than the stepped portion, whereby the slope and the stepped portion are formed. The pressure sensor according to claim 1, wherein a gap for preventing the recess from being sealed is formed therebetween. 3. The pressure sensor according to claim 1, wherein the electrodes provided on both front and back surfaces of the sensor body have the same bonding area. 4. The pressure sensor according to claim 1, wherein a positioning protrusion is formed on the sensor body. 5. A three-dimensional circuit board, comprising a three-dimensional circuit board and a sensor on the surface.
A recess for mounting the sir chip is formed
In addition, the inner surface of the recess has a slope of approximately 60 degrees or more and less than 90 degrees.
It has a sensor main body with a slope for wiring that has,
Forming a first electrode on the surface of the sensor body
A second electrode electrically connected to the first electrode
It is formed on the back surface of the sensor body, and the first electrode and the front
Wiring pattern to electrically connect with the sensor chip
Pressure sensor is formed so as to pass through at least the slope, and the recess serves as a pressure receiving surface.