JP3042344B2 - Semiconductor 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 small semiconductor pressure sensor which is surface-mounted on a mother board.

[0002]

2. Description of the Related Art An example of a conventional semiconductor pressure sensor will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a state where the semiconductor pressure sensor is mounted on the motherboard. In the figure, a semiconductor pressure sensor has a semiconductor pressure sensor chip 1 bonded to a pedestal 2 by an anodic bonding method or the like, a concave portion 3a is provided in the center of the bottom surface of a resin-molded package body 3, and the pedestal 2 is bonded with an adhesive 4 And so on. In the upper part of the package body 3, a through hole 2 formed in the base 2 is provided.
A pressure introduction port 3b communicating with the semiconductor pressure sensor chip 1 through a is formed. Further, the opening of the concave portion 3a formed on the bottom surface of the package body 3 is closed by the lid 5, whereby the inside of the concave portion 3a becomes a pressure reference chamber 3c with improved sealing performance.

A semiconductor pressure sensor chip 1 is formed by forming a diaphragm 1a having a pressure-receiving surface on one side for converting pressure into stress and a strain gauge (not shown) on a single-crystal silicon plate. A change in pressure is converted into a change in electrical resistance by the effect and output.

The semiconductor pressure sensor chip 1 and the leads 6 integrally formed on the package body 3 are connected by bonding wires 7 such as Au wires, and the leads 6 are mounted on a mother board 8 on which the semiconductor pressure sensors are mounted. In order to connect with the formed wiring pattern (not shown), after cutting the tie bar of the lead frame serving as the lead 6, the tip end of the portion protruding from the side surface of the package body 3 is bent substantially vertically downward. The tips of the leads 6 are inserted into sockets 9 mounted on the motherboard 8. by this,
The semiconductor pressure sensor is mounted on the mother board 8.

Next, a different example of the conventional semiconductor pressure sensor will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a state where the semiconductor pressure sensor is mounted on the motherboard. However, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and detailed description is omitted. The example shown in FIG. 4 differs from the example shown in FIG. 3 in the shape of the leads and the mounting method. In the example shown in FIG. 4, the leads 10 protruding from the side surface of the package body 3 are bent obliquely downward,
Further, the tip portion is bent so as to be substantially horizontal in a direction opposite to the package body 3 side. The wiring pattern 1 is formed on the mother board 8 corresponding to the shape of the lead 10.
1 is formed and joined to the tip of the lead 10 by the solder 12.

[0006]

In the semiconductor pressure sensor shown in FIGS. 3 and 4, since the lead 6 or the lead 10 protrudes largely from the side surface of the package body 3, the mounting area of the semiconductor pressure sensor becomes large. There was a problem that it would. In the example shown in FIG.
It is necessary to previously mount the socket 9 for inserting the connector on the mother board 8, which increases the number of parts and increases the cost.

[0007] The present invention has been made in view of the above problems,
An object of the present invention is to provide a structure of a semiconductor pressure sensor which is inexpensive and can be downsized.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor pressure sensor including a semiconductor pressure sensor chip having a diaphragm for converting pressure into stress, and a semiconductor pressure sensor chip supporting the semiconductor pressure sensor chip. A package body in which a pedestal, a recess for accommodating the semiconductor pressure sensor chip and the pedestal therein, and a pressure inlet are formed, and the semiconductor pressure sensor is electrically connected to the semiconductor pressure sensor by wire bonding and is external to the package body. A semiconductor pressure sensor having a lead drawn out to the package body, wherein the lead is drawn out to the side of the package body and bent toward the bottom side of the package body so as to substantially along the side surface of the package body, and further, Wherein the portion is bent substantially along the bottom surface of the package body. Is shall.

A semiconductor pressure sensor according to a second aspect of the present invention includes a semiconductor pressure sensor chip having a diaphragm for converting pressure into stress, a pedestal supporting the semiconductor pressure sensor chip, and a semiconductor pressure sensor chip and the pedestal. A concave body to be housed therein, and a package main body having a pressure inlet formed therein, and a lead electrically connected to the semiconductor pressure sensor by wire bonding and led out of the package main body. In the semiconductor pressure sensor to be mounted, the concave portion is formed on the bottom side of the package main body, and when the semiconductor pressure sensor is mounted on the mother board, the package main body is
The package body is formed so as to cover at least one element mounted on the mother board and a peripheral portion thereof at the location of the concave portion, and the lead is drawn out to the side of the package body. Are bent to the bottom surface side of the package main body substantially along the side surfaces of the package body, and further, the tip portion is bent substantially along the bottom surface of the package main body.

A semiconductor pressure sensor according to a third aspect of the present invention is the semiconductor pressure sensor according to the second aspect, wherein at least one of the elements uses the temperature of the semiconductor pressure sensor chip for temperature compensation of the semiconductor pressure sensor. The element is required to be maintained at a temperature substantially equal to the temperature.

[0011]

According to the semiconductor pressure sensor of the present invention, the lead is drawn out to the side of the package body of the semiconductor pressure sensor, and is bent toward the bottom surface side of the package body substantially along the side surface of the package body. The tip portion is bent substantially along the bottom surface of the package body, and the tip portion of the lead is joined to a wiring pattern formed on the motherboard by soldering or the like, and is surface-mounted. According to this structure, the lead does not largely protrude laterally from the package body, so that the semiconductor pressure sensor can be downsized.

According to a second aspect of the present invention, in the semiconductor pressure sensor, the package body covers at least one element mounted on the mother board and a peripheral portion thereof at the concave portion. A package body is constituted. With this configuration, other elements can be mounted in the mounting area of the semiconductor pressure sensor on the motherboard, so that the size of the motherboard can be reduced.

The semiconductor pressure sensor according to a third aspect of the present invention is the semiconductor pressure sensor according to the second aspect, wherein at least one of the elements is connected to a semiconductor pressure sensor chip for temperature compensation of the semiconductor pressure sensor. The temperature compensation element (temperature compensation element) is required to be maintained at a temperature substantially equal to the temperature. With this configuration, the temperature compensation element and the semiconductor pressure sensor chip have the same pressure reference. Since the temperature of the temperature compensating element and the temperature of the semiconductor pressure sensor chip are substantially equal to each other, the temperature compensation can be performed with high accuracy.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the semiconductor pressure sensor according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a state where a semiconductor pressure sensor is mounted on a mother board. However, the same components as those shown in FIG. 4 are denoted by the same reference numerals. In the figure, a semiconductor pressure sensor chip 1 is joined to a pedestal 2 made of a Pyrex glass material or the like by an anodic bonding method or the like. It is mounted with an adhesive 4 or the like.

The semiconductor pressure sensor chip 1 passes through a through hole 2a formed in the pedestal 2 at the upper part of the package body 3.
Is formed. Further, the opening of the concave portion 3a is closed by the lid 5, so that the inside of the concave portion 3a is a pressure reference chamber 3 having an improved hermeticity.
c. The internal pressure of the pressure reference chamber 3c may be set to atmospheric pressure, or may be set to vacuum.

The semiconductor pressure sensor chip 1 is formed by forming a diaphragm 1a having a pressure-receiving surface on one side, which converts pressure into stress, and a strain gauge (not shown) on a single-crystal silicon plate. A change in pressure is converted into a change in electrical resistance by the effect and output.

The semiconductor pressure sensor chip 1 and the leads 13 integrally formed on the package body 3 are connected by bonding wires 7 such as Au wires. Lead 13
After the tie bar of the lead frame serving as the lead 13 is cut, the portion pulled out to the side of the package body 3 is bent to the bottom surface side of the package body 3 so as to be substantially along the side surface of the package body 3, and furthermore, The tip is
It is bent substantially along the bottom surface of the package body 3. The tips of the leads 13 are joined to the wiring patterns 14 formed on the mother board 8 (copper-clad laminate, ceramic, metal base board, or the like) by the solder 12 or the like.
According to the structure shown in FIG. 1, the lead does not largely protrude to the side of the package body 3, so that the semiconductor pressure sensor can be downsized and the mounting area can be reduced.

Referring to FIG. 2, another embodiment of the semiconductor pressure sensor according to the present invention will be described. FIG. 2 is a cross-sectional view showing a state where the semiconductor pressure sensor is mounted on the motherboard. However, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted. In the embodiment shown in FIG. 2, the leads are configured in the same manner as the leads 13 of the embodiment shown in FIG. 1, and the package body 3 is mounted on the mother board 8 at the concave portion 3a. It is configured to cover the operational amplifier IC 15 and its peripheral portion (for example, a region where a bonding wire connected to the operational amplifier IC 15 and a part of a wiring pattern connected to the bonding wire are formed). FIG.
1, the lid 5 of the embodiment shown in FIG. 1 has been removed.

The operational amplifier IC 15 is an element having a function of amplifying the output of the semiconductor pressure sensor chip 1 (strain gauge) and performing temperature compensation. In the embodiment shown in FIG. 2, the operational amplifier IC 15 is disposed inside the pressure reference chamber 3d.
Elements other than the operational amplifier IC15 may be arranged. Further, for example, a plurality of elements such as the operational amplifier IC 15 and a resistance element for adjusting the variation of the electrical characteristics may be arranged.

The tip of the lead 13, which is constructed as described above and is substantially along the bottom surface of the package body 3,
The semiconductor pressure sensor is mounted on the motherboard 8 by bonding to the wiring pattern 14 formed on the motherboard 8.
In this case, the gap between the bottom surface of the package main body 3 and the motherboard 8 may be filled with a sealing agent 16 made of a silicone resin or the like so as to increase the sealing property of the pressure reference chamber 3d. However, when this sealing is performed, when the internal pressure of the pressure reference chamber 3d is made equal to the atmospheric pressure, intrusion of foreign matter or moisture into the pressure reference chamber 3d is suppressed and the internal pressure is made equal to the atmospheric pressure. , Small air holes (not shown) are formed in advance. This ventilation hole is provided in a part of a gap between the bottom surface of the package
6 may be formed so as not to be filled, or a hole or groove may be formed in the package body 3 and used as a vent. Further, a through hole or the like may be formed on the mother substrate 8 side and used as a vent hole.

The shape of the package body is not limited to the embodiment. Further, in the embodiments, the element has been described as an operational amplifier IC, but is not limited to the embodiment.

[0022]

As described above, in the semiconductor pressure sensor according to any one of the first to third aspects, the lead for electrically connecting the semiconductor pressure sensor and the wiring pattern formed on the motherboard is provided in the package. Since it is pulled out to the side of the main body and bent almost along the side and bottom of the package main body, the mounting area of the semiconductor pressure sensor can be significantly reduced,
The size of the semiconductor pressure sensor can be reduced.

Further, in the semiconductor pressure sensor according to the second and third aspects, the package body covers at least one element mounted on the mother board and a peripheral portion thereof at the concave portion. Since the package body is configured, other elements can be mounted in the mounting area of the semiconductor pressure sensor on the motherboard, and the motherboard can be reduced in size.

Further, in the semiconductor pressure sensor according to the present invention, at least one of the elements mounted on the motherboard and arranged in the pressure reference chamber is connected to a semiconductor pressure sensor for temperature compensation of the semiconductor pressure sensor. Since the element (temperature compensation element) must be maintained at a temperature substantially equal to the temperature of the sensor chip, the semiconductor pressure sensor chip and the temperature compensation element can be arranged in the same pressure reference chamber, and the semiconductor pressure sensor chip Since the temperature and the temperature of the temperature compensation element can be made substantially equal, there is an effect that temperature compensation can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a semiconductor pressure sensor of the present invention.

FIG. 2 is a sectional view showing another embodiment of the semiconductor pressure sensor of the present invention.

FIG. 3 is a sectional view showing an example of a conventional semiconductor pressure sensor.

FIG. 4 is a sectional view showing a different example of the conventional semiconductor pressure sensor.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 semiconductor pressure sensor chip 1 a diaphragm 2 pedestal 3 package body 3 a recess 3 b pressure inlet 8 mother board 13 lead 15 operational amplifier IC (for temperature compensation of element and semiconductor pressure sensor, the temperature is substantially equal to the temperature of semiconductor pressure sensor chip. Elements that need to be kept at temperature)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-218739 (JP, A) JP-A-7-38122 (JP, A) JP-A-4-312980 (JP, A) 113045 (JP, U) Fully open Hei 5-64748 (JP, U) Fully open Showa 64-38545 (JP, U) Really open Showa 63-105332 (JP, U) Really open 3-125219 (JP, U) Hikaru 1-165436 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01L 9/04 H01L 29/84

Claims (3)

(57) [Claims] A semiconductor pressure sensor chip on which a diaphragm for converting pressure into stress is formed; a pedestal supporting the semiconductor pressure sensor chip; a recess accommodating the semiconductor pressure sensor chip and the pedestal therein; In a semiconductor pressure sensor including a package body having a pressure inlet formed therein, and a lead that is electrically connected to the semiconductor pressure sensor by wire bonding and is drawn out of the package body, the lead may be connected to the package body. The package body is drawn out to the side and bent to the bottom surface side of the package body substantially along the side surface of the package body, and the tip portion is further bent substantially along the bottom surface of the package body. Semiconductor pressure sensor. 2. A semiconductor pressure sensor chip having a diaphragm for converting pressure into stress, a pedestal supporting the semiconductor pressure sensor chip, a recess accommodating the semiconductor pressure sensor chip and the pedestal therein, and A package main body having a pressure inlet formed therein, and a lead that is electrically connected to the semiconductor pressure sensor by wire bonding and is drawn out of the package main body,
In the semiconductor pressure sensor mounted on the motherboard, the recess is formed on the bottom surface side of the package body, and when the semiconductor pressure sensor is mounted on the motherboard, the package body is located at the location of the recess. At least one element mounted on the motherboard is formed so as to cover a peripheral portion thereof, and the lead is drawn out to the side of the package body and substantially extends on a side surface of the package body. A semiconductor pressure sensor, wherein the semiconductor pressure sensor is bent toward the bottom surface of the package main body so as to extend along the bottom surface of the package main body. 3. The semiconductor device according to claim 1, wherein at least one of the elements is an element whose temperature needs to be maintained at a temperature substantially equal to the temperature of the semiconductor pressure sensor chip for temperature compensation of the semiconductor pressure sensor. The semiconductor pressure sensor according to claim 2.