JPH10185722A - Pressure detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure detector whose noise-resistant property is excellent by a method wherein a land part used to connect a chip cover and a land part used to connect a pressure introduction port are connected to a ground level. SOLUTION: A pressure introduction port 9 is arranged and installed on the rear side of a circuit board which is connected electrically to a pressure sensor chip 4, and a chip cover 10 which covers the pressure sensor chip 4 is arranged and installed on the circuit board. At this time, an external noise from a surrounding atmosphere having a fear of influencing the pressure sensor chip 4 and a first wiring pattern 8e is shielded by the chip cover 10 and the pressure introduction port 9 in addition to a noise treatment on a circuit in conventional cases, the noise is grounded to a ground level via a second wiring pattern 8h and a third wiring pattern 8k, and a noise-resistant property which is more excellent than that in conventional cases is obtained. In addition, since an airtight property in the bonding face of the chip cover 10 to the circuit board can be ensured satisfactorily, a pressure can be detected precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure detector, and more particularly to a pressure detector excellent in noise resistance.

[0002]

2. Description of the Related Art A known pressure detector has a structure in which a pressure introduction port is bonded to an opposite surface of a circuit board on which a pressure sensor chip is mounted. For example, Japanese Patent Laid-Open No. 4-2
The pressure detector disclosed in Japanese Patent No. 5737 and shown in FIG.
A predetermined wiring pattern is formed, a through hole 1a for transmitting pressure to a pressure sensor chip described later is formed, and a diaphragm 2 is formed from a silicon material or the like on a circuit board 1 made of a ceramic material. A semiconductor type pressure sensor chip 4 having a glass pedestal 3 formed of Pyrex glass or the like below is bonded to an epoxy-based or silicon-based adhesive such that the through hole 1a and the pressure introducing hole 3a formed in the glass pedestal 3 face each other. Circuit board 1
After wire bonding between the electrode portion 1b and the electrode terminal (not shown) of the pressure sensor chip 4 using a gold wire 5 or the like, the pressure sensor chip 4 is covered with a chip cover 6 to isolate the pressure sensor chip 4 from the surrounding atmosphere. ing. The chip cover 6 is disposed and fixed to the circuit board 1 with an epoxy adhesive. On the other hand, on the back side of the circuit board 1, a flange portion 7 a from which the opposing surface of the circuit board 1 is drawn outward, and the pressure from the medium is applied to the pressure sensor chip 4.
Pressure introduction port 7 formed with a pressure introduction section 7b for guiding the pressure to the circuit board 1 is disposed such that the pressure introduction section 7b corresponds to the through hole 1a.
Is fixed to the upper end surface of the substrate via an epoxy adhesive.

[0003]

Such a pressure detector is sometimes mounted on a vehicle. Under such an environment, the pressure detector is affected by various noises such as electromagnetic noise, radio noise, and ignition noise. Equipment that easily operates based on data from this pressure detector (for example, an intake pressure gauge)
As a method of countering such noise, it is conceivable to mount a capacitor or the like on another circuit board (not shown) to absorb the noise, but it is not possible to completely absorb the noise. There is a need for a structure having noise resistance of the pressure detector. Then, the present invention pays attention to the above-mentioned problem, and provides a pressure detector excellent in noise resistance structurally.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pressure introducing device for transmitting pressure to a pressure sensor chip on a back surface of a circuit board electrically connected to the pressure sensor chip. In a pressure detector in which a port is provided and a chip cover that covers the pressure sensor chip is provided on a front surface side of the circuit board, an electrode portion electrically connected to the pressure sensor chip on the circuit board. A first wiring pattern connected to the electrode portion, a first land portion connected to the chip cover, a second land portion connected to the pressure introducing port, the first and second wiring patterns,
And a second and third wiring patterns for connecting the land portions to the ground level.

[0005] A first side of the pressure sensor chip is provided on the back side of a circuit board electrically connected to the pressure sensor chip.
A pressure introducing port having a pressure introducing portion for transmitting the pressure, and covering the pressure sensor chip on the front surface side of the circuit board, for transmitting a second pressure to the pressure sensor chip. In a pressure detector provided with a chip cover having a pressure port, the circuit board,
An electrode portion electrically connected to the pressure sensor chip,
A first wiring pattern connected to the electrode portion, a first land portion connected to the chip cover, a second land portion connected to the pressure introduction port, and the first and second land portions. And second and third wiring patterns connected to the ground level.

The first land portion is formed so as to surround the electrode portion, and the electrode portion is connected to first and second blind through-holes and the first and second blind through-holes. The first land portion is electrically separated from the first land portion via the first wiring pattern, and is electrically drawn to the end of the circuit board.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a pressure introducing port 9 is provided on the back side of a circuit board 8 electrically connected to a pressure sensor chip 4, and a chip cover 10 for covering the pressure sensor chip 4 is provided on the circuit board. A plurality of electrode portions 8b connected to the circuit board 8 by wire bonding with the pressure sensor chip 4; a first wiring pattern 8e connected to each electrode portion 8b; A cover connection land (first land portion) 8g for connecting the chip cover 10 by solder, a port connection land (second land portion) 8j for connecting the pressure introduction port 9 by solder, a cover connection land 8g and a port connection. Second and third wiring patterns 8h and 8k for connecting land 8j to the ground level
The external noise from the surrounding atmosphere that may affect the pressure sensor chip 4 and each first wiring pattern 8e is added to the noise processing on the conventional circuit, and the chip cover 10 and The noise is shielded by the pressure introducing port 9, and the noise is eliminated by the second and third wiring patterns 8h, 8h.
Since it is grounded to the ground level via 8k, it is possible to obtain a pressure detector having more excellent noise resistance than before.

A cover connection land 8g is formed so as to surround each electrode portion 8b connected to the pressure sensor chip 4 by wire bonding, and each electrode portion 8b is connected to the first and second blind through holes 8c and 8d. , And each of the blind through holes 8 c and 8 d formed in the circuit board 8.
Is electrically separated from the cover connection land 8g via the first wiring pattern 8e connected to the first wiring pattern 8e, and is electrically drawn out to each first electrode terminal 8f formed at the end of the circuit board 8; 10 can be fixed via solder to the substantially donut-shaped cover connection land 8g formed on the circuit board 8, so that the bonding strength of the chip cover 6 to the conventional pressure detector that fixes the chip cover 6 to the circuit board 1 with an adhesive is higher. In addition, in a so-called differential pressure type pressure detector in which a pressure port 10a is formed in the chip cover 10 and pressure is introduced, the airtightness at the joint surface between the chip cover 10 and the circuit board 8 can be improved. As a result, accurate pressure detection can be performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments shown in the accompanying drawings, but the same or corresponding parts as those in the conventional example will be denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a sectional view of a main part showing a pressure detector of the present invention, and FIGS. 2 to 4 are views showing a circuit board of the present invention.

As an embodiment of the present invention, the first pressure and the second pressure
An example of a so-called differential pressure type pressure detector which introduces pressure and detects the difference will be described. In the pressure detector described in FIGS. 1 to 4, 4 is a pressure sensor chip, 8 is a circuit board, 9 is a pressure introduction port, 10 is a chip cover, 11
Is an electrode lead.

The pressure sensor chip 4 includes a diaphragm 2 and a glass pedestal 3 as in the conventional example.
3 is joined by anodic bonding. A pressure introducing hole 3a for transmitting pressure to the diaphragm 2 is formed substantially at the center of the glass pedestal 3, and a pressure introducing port 9 described later in detail is connected to a bottom surface of the glass pedestal 3 via solder. Metallization layer (not shown) is formed.

The circuit board 8, which is a feature of the present invention, is a multilayer board made of a material such as a resin containing glass fiber or ceramic. At a substantially center of the circuit board 8, a through-hole 8a penetrating from the front surface to the back surface is formed.
A plurality of electrode portions 8b for electrically connecting to electrode terminals (not shown) of the pressure sensor chip 4 by wire bonding are formed around the periphery of the electrode portion 8a.
b is the first and second blind through holes 8c and 8d
And a first wiring pattern 8e connected to the first and second blind through holes 8c and 8d and formed inside the circuit board 8 so as to be electrically separated from a cover connection land described later. The first electrode terminal 8f is formed at the end of the circuit board 8 for connecting the electrode lead 11, which will be described in detail later. In addition, each electrode section 8
A substantially donut-shaped cover connection land (first land portion) 8g for soldering a chip cover 10, which will be described in detail later, is formed around each electrode portion 8b so as to surround each electrode portion 8b. The cover connection land 8g is extended to a second electrode terminal 8i for connecting an electrode lead 11 formed at an end of the circuit board 8 by a second wiring pattern 8h.

On the other hand, on the back side of the circuit board 8, first and second electrode terminals 8f and 8i formed on the front side of the circuit board 8 are provided.
And a pair of electrode terminals (first and second electrode terminals 8f, 8f).
i) and a substantially donut-shaped port connection land (second connection) for connecting the pressure introduction port 9 described later in detail via solder.
Lands 8j are formed, and the first and second port connection lands 8j are formed on the back side of the circuit board 8.
Electrically connected to a third wiring pattern 8k that covers substantially the entire area except for the electrode terminals 8f and 8i of the circuit board 8, and the third wiring pattern 8k is electrically connected to the second electrode terminal 8i on the back side of the circuit board 8. Has been drawn to. In the circuit board 8, the third wiring pattern 8 k connected to the ground level is formed so as to cover substantially the entire area of the rear surface of the insulating substrate 8 except for the formation of the electrode terminals. It has excellent properties.

The pressure introduction port 9 is connected to the pressure sensor chip 4
In consideration of the difference in thermal expansion of the glass pedestal 3, the thermal expansion coefficient is approximated to that of the glass pedestal 3, and is made of a metal material such as Kovar or 4-2 alloy which can be soldered. A flange 9a corresponding to the port connection land 8j is formed. The pressure introduction port 9 is formed with a through hole penetrating from the lower end to the upper end of the pressure introduction port 9, and this through hole is for transmitting the first pressure to the diaphragm 2 of the pressure sensor chip 4. It constitutes the pressure introducing part 9b.

The chip cover 10 is made of, for example, nickel-plated iron-based material.
Is disposed on the cover connection land 8g of the circuit board 8 via solder so as to cover the pressure sensor chip 4 from the surrounding atmosphere. A pressure port 10a for transmitting a second pressure to the pressure sensor chip 4 is formed at an upper end portion of the chip cover 10.
A flange portion 10b corresponding to the cover connection land 8g of the circuit board 8 is formed on the surface of the circuit board 8 opposite to the surface 0.

The electrode lead 11 is electrically fixed to the first and second electrode terminals 8f and 8i by solder or the like.
The electrode lead 11 connected to the first electrode terminal 8f draws an electric signal output from the pressure sensor chip 4 to another circuit board (not shown) or applies a drive voltage for driving the pressure sensor chip 4. And is electrically connected to the pressure sensor chip 4 through the blind through holes 8c and 8d and the first wiring pattern 8e. The electrode lead 11 connected to the second electrode terminal 8i is grounded to the ground level via another circuit board (not shown). For example, a chip connected to the cover connection land 8g and the port connection land 8j When the cover 10 and the pressure introduction port 9 receive external noise from the surrounding atmosphere, this noise is brought to the ground level via the electrode leads 11 connected to the second and third wiring patterns 8h and 8k and the second electrode terminals 8i. Grounded.

The pressure detector constituted by each of the above components is configured such that the flange 9a of the pressure introducing port 9 is fixed to the port connection land 8j formed on the back surface side of the circuit board 8 via solder, so that the circuit board 8 Is closed by the pressure introduction port 9, and the through hole 8 a and the pressure introduction port 9 are closed.
And the upper end of the mounting recess 12 form a mounting recess 12 for disposing the pressure sensor chip 4. The metalization layer formed on the bottom surface of the glass pedestal 3 and the pressure introduction port 9 are soldered to the mounting recess 12 such that the pressure introduction portion 9b of the pressure introduction port 9 and the pressure introduction hole 3a of the glass pedestal 3 face each other. The pressure sensor chip 4 is connected to the mounting recess 1
2 are arranged. Then, the electrode terminals (not shown) of the pressure sensor chip 4 provided in the mounting recess 12 and the respective electrode portions 8b of the circuit board 8 are wire-bonded with the gold wire 5 or the like, and the pressure sensor chip 4 is removed from the surrounding atmosphere. For isolation, the flange portion 10b of the chip cover 10 is
Are arranged via solder so as to correspond to the cover connection lands 8g, and each electrode lead 11 is connected to the first and second electrode terminals 8f and 8f.
8i, a differential pressure type pressure detector is completed.

With this configuration, the pressure applied to the pressure introducing portion 9b of the pressure introducing port 9 is
Reaches the diaphragm 2 through the pressure introducing hole 3a of the glass pedestal 3, when the diaphragm 2 is distorted, an output corresponding to the pressure is generated by the first and second blinds formed on the circuit board 8. It reaches the electrode lead 11 connected to the first electrode terminal 8f through the through holes 8c and 8d and the first wiring pattern 8e, and is taken out of the electrode lead 11 to the outside.

When such a pressure detector is installed in a vehicle or the like, it is affected by various noises such as electromagnetic noise, radio noise, and ignition noise. Noise processing,
The structure of the present invention, that is, the chip cover 10 covering the pressure sensor chip 4 and the pressure introducing port 9 for disposing the pressure sensor chip 4 are formed of a metal material, and the circuit board 8
Cover connection lands 8g and port connection lands 8j that are grounded to the ground level via the second and third wiring patterns 8h and 8k so as to surround the peripheral portion where the pressure sensor chip 4 is disposed. The chip cover 10 is connected to the connection land 8g and the port connection land 8j via solder.
And the structure in which the pressure introduction port 9 is provided,
External noise from the surrounding atmosphere, which may affect the pressure sensor chip 4 and each first wiring pattern 8e,
Shielded by a chip cover 10 and a pressure introduction port 9,
Since the noise can be grounded to the ground level via the second and third wiring patterns 8h and 8k, a pressure detector having more excellent noise resistance than the conventional one can be obtained.

Further, since the chip cover 10 can be fixed to the circuit board 8 via solder, it is possible to improve the bonding strength with respect to the conventional pressure detector in which the chip cover 6 is fixed to the circuit board 1 with an adhesive. Moreover, in a differential pressure type pressure detector in which the second pressure is introduced through the pressure port 10a of the chip cover 10, airtightness at the joint surface between the chip cover 10 and the circuit board 8 can be ensured well. As a result, accurate pressure detection is possible.

In this embodiment, the through holes 8 of the circuit board 8 are provided.
a and the mounting recess 1 composed of the upper end of the pressure introduction port 9
2, the pressure sensor chip 4 is disposed as an example, but a conventional pressure detector in which the pressure sensor chip 4 and the pressure introduction port 7 are disposed on the circuit board 1 as shown in FIG. Similar effects can be obtained by applying the structure of the present invention to the above structure.

In the present embodiment, a differential pressure type pressure detector for introducing the first and second pressures from the pressure introducing port 9 and the chip cover 10 has been described as an example. Pressure detector (pressure detector as shown in Fig. 5)
The structure of the present invention may be applied to the present invention.

The cover connection land 8g and the port connection land 8j of this embodiment are formed in a substantially donut shape.
And the land shape is not limited to this embodiment.

[0025]

According to the present invention, a pressure introducing port for transmitting pressure to the pressure sensor chip is provided on the back side of the circuit board electrically connected to the pressure sensor chip. In a pressure detector having a chip cover for covering the pressure sensor chip on a front surface side, an electrode portion electrically connected to the pressure sensor chip and a first electrode connected to the electrode portion on the circuit board. A wiring pattern, a first land connecting the chip cover,
A pressure sensor comprising: a second land connecting the pressure introducing port; and second and third wiring patterns connecting the first and second lands to a ground level. A pressure introducing port having a pressure introducing portion for transmitting a first pressure to the pressure sensor chip is disposed on the back side of the circuit board electrically connected to the chip, and on the front side of the circuit board. A pressure detector that covers the pressure sensor chip and includes a chip cover having a pressure port for transmitting a second pressure to the pressure sensor chip, wherein the circuit board is electrically connected to the pressure sensor chip. An electrode part to be connected, a first wiring pattern to connect to the electrode part, a first land part to connect the chip cover, a second land part to connect the pressure introduction port, And second and third wiring patterns for connecting the first and second lands to the ground level. In addition to the conventional noise processing on the circuit, external noise from the surrounding atmosphere is also reduced. Since the second and third wiring patterns are grounded to the ground level, it is possible to obtain a pressure detector having better noise resistance than the conventional one.

The first land portion is formed so as to surround the electrode portion, and the electrode portion is connected to the first and second blind through holes and the first and second blind through holes. The first land portion is electrically separated from the first land portion through the first wiring pattern, and is electrically pulled out to an end of the circuit board, and the entire periphery of the chip cover is connected to the circuit board. Since it can be fixed to the formed lands via solder, the joining strength can be improved, and the airtightness at the joining surface between the chip cover and the circuit board can be secured well, so that accurate pressure Can be detected.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a pressure detector of the present invention.

FIG. 2 is a plan view showing a state in which the circuit board of the present invention is viewed from the surface.

FIG. 3 is a sectional view of a main part of the circuit board according to the present invention;

FIG. 4 is a plan view showing a state in which the circuit board of the present invention is viewed from the back surface.

FIG. 5 is a sectional view of a main part showing a conventional pressure detector.

[Explanation of symbols]

 Reference Signs List 4 pressure sensor chip 8 circuit board 8b electrode section 8c first blind through hole 8d second blind through hole 8e first wiring pattern 8f first electrode terminal 8g cover connection land (first land section) 8h second 8i Second electrode terminal 8j Port connection land (second land portion) 8k Third wiring pattern 9 Pressure introduction port 9b Pressure introduction section 10 Chip cover 10a Pressure port

Claims (3)

[Claims] 1. A pressure introducing port for transmitting pressure to the pressure sensor chip is provided on a back side of a circuit board electrically connected to the pressure sensor chip, and a pressure introducing port is provided on a front side of the circuit board. In the pressure detector provided with a chip cover that covers the pressure sensor chip, the circuit board, an electrode portion electrically connected to the pressure sensor chip, a first wiring pattern connected to the electrode portion, A first land for connecting the chip cover, a second land for connecting the pressure introduction port, and the first and second lands.
And a second and a third wiring pattern for connecting the land portion to the ground level. 2. A pressure introducing port having a pressure introducing portion for transmitting a first pressure to the pressure sensor chip is provided on a back side of a circuit board electrically connected to the pressure sensor chip, A pressure detector that covers the pressure sensor chip on the front surface side of the circuit board and that includes a chip cover having a pressure port for transmitting a second pressure to the pressure sensor chip; An electrode part electrically connected to the pressure sensor chip, a first wiring pattern connected to the electrode part, a first land part connected to the chip cover, and a second part connected to the pressure introduction port. A pressure detector, comprising: a land portion; and second and third wiring patterns for connecting the first and second land portions to a ground level. 3. The first land portion is formed so as to surround the electrode portion, and the electrode portion is connected to first and second blind through-holes and the first and second blind through-holes. 2. The semiconductor device according to claim 1, wherein the first land portion is electrically separated from the first land portion via the first wiring pattern, and is electrically drawn to an end of the circuit board.
Alternatively, the pressure detector according to claim 2.