JPH11237401A - Semiconductor acceleration sensor and its sealing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor acceleration sensor whose semiconductor sensor part does not corrode owing to entry of external moisture. SOLUTION: The sensor is equipped with a housing 1 which is formed in a nearly rectangular bottomed box shape having four side walls 11 and a box- shaped inside 12, a semiconductor sensor part 2 provided with a sensor chip 21 which detects acceleration, terminal parts 3 which are each formed in a long-size plate shape having a piece 32 folded in a nearly L shape from one piece 31 and have one end 31 connected to the semiconductor sensor part 2 and the base end part 32a of the other piece 32 of specific plate thickness led out of the 1st side wall 11a of the housing, and a cover 4 which has a cover bottom part 41 and a side part 42 and is formed in a nearly bottomed box shape and sealed with the four side walls 11 of the housing 1; and the housing 1 has groove depth δ corresponding to the specific plate thickness and a cut groove 11b containing the base end part 32a of the piece 32 is provided on the 1st side wall 11a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed type semiconductor acceleration sensor used for automobiles, home electric appliances and the like, the inside of which is hermetically sealed from the outside.

[0002]

2. Description of the Related Art Conventionally, there has been a semiconductor acceleration sensor of this type having a structure shown in FIGS. This includes a housing A having a substantially rectangular bottomed box shape having a side wall A1 and a box-shaped interior A2, a semiconductor sensor portion B provided with a sensor chip B1 for detecting acceleration, and a piece C1. And a long plate having another piece C2 bent substantially in an L-shape from the end of the piece C1. The piece C1 is connected to the semiconductor sensor portion B and the side C1 is connected to the side wall A1 of the housing A. It has a plurality of terminal boards C which are led out, and a cover D which fits into a fitting groove D1 provided in the housing A.

More specifically, as shown in FIG. 4, the terminal plate C is integrally formed with the housing A by a mold, and a terminal press pin is provided in the mold, and one piece C1 is held down by the terminal press pin. And are integrally formed in a fixed state. Accordingly, the housing A has a pin insertion hole A3 communicating with the piece C1 of the terminal plate C.

[0004]

In the conventional semiconductor acceleration sensor described above, the semiconductor sensor is mounted on an automobile or the like, and the semiconductor sensor section can detect the acceleration applied to the automobile or the like.

However, the fitting portion D2 between the housing A and the cover D and the end portion C11 of the piece C1 are not sealed with the housing A, and the box-shaped interior A2 has the fitting portion D2.
2. It communicates with the outside through the end C11 of the piece C1 and the pin insertion hole A3, and is not sealed. Therefore, since there is no airtightness, moisture or the like intrudes from the outside, and in the sensor chip B1 of the semiconductor sensor portion B for detecting acceleration, the aluminum wiring formed on the surface of the semiconductor may be corroded by the moisture.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor acceleration sensor in which a semiconductor sensor portion does not corrode due to intrusion of moisture from the outside. .

[0007]

According to another aspect of the present invention, there is provided a semiconductor acceleration sensor having a substantially rectangular bottomed box shape having a side wall and a box-shaped interior. A semiconductor sensor portion provided with a sensor chip for detecting acceleration, and a long plate having one piece and another piece bent from the one piece into a substantially L-shape. The base end of another piece connected to the housing and having a predetermined plate thickness has a plurality of terminal plates protruded from at least one side wall of the housing, a cover bottom portion and side portions, and is formed in a substantially bottomed box shape. And a cover sealed to the side wall of the housing, wherein the box-shaped interior is sealed from the outside, wherein the housing has a groove depth corresponding to the predetermined plate thickness. Notch groove for receiving the base end of the other piece , It is a configuration provided on at least one side wall.

According to a second aspect of the present invention, in the semiconductor acceleration sensor according to the first aspect, a pin insertion hole communicating with one piece of the terminal plate is provided in the housing. With the insertion hole sealed with a sealing material, a sealing hole for sealing the inside of the box is provided at the bottom of the cover.

According to a third aspect of the present invention, there is provided a method for sealing a semiconductor acceleration sensor according to the first or second aspect, wherein the one piece and the one piece are bent into a substantially L-shape. One piece of a plurality of terminal plates formed in a long plate shape having another piece formed is connected to the semiconductor sensor portion,
A base end of another piece having a predetermined plate thickness is led out from at least one side wall of a housing having a substantially rectangular bottomed box shape having a side wall and a box-shaped interior. The end portion is housed in a notch groove provided in at least one side wall of the housing with a groove depth corresponding to a predetermined plate thickness, and formed into a substantially bottomed box shape having a cover bottom portion and side portions. The side of the cover is sealed to the side wall of the housing.

According to a fourth aspect of the present invention, there is provided a method of sealing a semiconductor acceleration sensor according to the third aspect, wherein a pin insertion hole communicating with one piece of the terminal plate is provided in the housing. The cover is sealed to the side wall of the housing, the pin insertion hole is primarily sealed with a sealing material, the sealing hole provided at the bottom of the cover is sealed, and the inside of the box is secondarily sealed. Configuration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

Reference numeral 1 denotes a housing made of an insulating resin.
A first side wall 11a, which is formed in a substantially rectangular bottomed box shape, has four side walls 11, a box-shaped interior 12, and a bottom portion 13 so that the four side walls 11 face each other along the longitudinal direction; A pin insertion hole 14 is provided in the bottom 13, which is constituted by a second side wall orthogonal to the side wall 11 a and opposed to each other.

Here, a plurality of notches 11b are formed in both first grooves.
The notch grooves 11b are arranged side by side on the side walls 11a, 11a, and each of the notch grooves 11b has a depth corresponding to a predetermined plate thickness δ of another piece 32 of the terminal plate 3 described later.

Reference numeral 2 denotes a semiconductor sensor unit, and a sensor chip 21
, A first stopper 22, and a second stopper 23. The sensor chip 21 includes a weight portion, a flexure portion, a sensor portion, and a support portion (all not shown) made of a thin silicon semiconductor, and detects three-axis acceleration. The weight portion is formed in a substantially square shape having four sides, and one end of each bending portion is connected to each piece of the weight portion so that the weight portion bends when acceleration is applied. A sensor section is formed in each bending section by a piezoresistor made of a semiconductor, and converts an acceleration into an electric signal based on the bending of each bending section to output an electric signal. The support part surrounds the outer peripheral edge of the weight part by providing a space, and supports the other end of the flexible part.

The first stopper 22 is made of Pyrex glass formed in a substantially square shape, and has a first contact surface (not shown) at the center of which a weight portion can contact, and the first contact surface thereof. An air gap is formed between the sensor chip 21 and the weight portion.
On one side. Similarly, the second stopper 23
Has a second contact surface (not shown) at the center of the Pyrex glass with which the weight portion can abut, and is formed between the second contact surface and the weight portion. A space is provided and fixed to the other surface of the sensor chip 21.

Reference numeral 3 denotes a terminal plate which is formed of copper or a copper alloy into a long plate shape and has one piece 31 and another piece 32 formed by bending the one piece 31 into a substantially L-shape. Are connected to the semiconductor sensor unit 2 via gold wires, and are configured in a plurality. The other piece 32 is bent in two steps from the base end 32a, the base end 32a is formed wider than the front end, and the other end 32 is formed from both first side walls 11a, 11a of the housing 1 facing each other. Each is derived and juxtaposed.

Here, the base end portion 32a of the other piece 32 is accommodated in the notch groove 11b of the housing 1, and the notch groove 11b has a groove depth corresponding to a predetermined plate thickness δ of the other piece 32. Therefore, the surface of the first side wall 11a of the housing 1 and the surface of the base end 32a form the same plane.

Reference numeral 4 denotes a cover, which is formed of an insulating resin into a bottomed box shape having a cover bottom 41 and side portions 42.
A cylindrical projection 43 having a sealing hole 43a is protruded from the cover bottom portion 41 to the outside, and the four side walls 1 of the housing 1 are formed.
1 sealed.

An assembling method and a sealing method of this will be described. First, the terminal plate 3 formed in a straight line using a mold provided with terminal holding pins is integrally formed with the housing 1 with one piece 31 being held down and fixed by the terminal holding pins. In the housing 1, a pin insertion hole 14 communicating with one piece 31 of the terminal plate 3 is formed, and a base end 32 a of the other piece 32 is led out from both first side walls 11 a of the housing 1.

Next, the semiconductor sensor unit 2 is mounted, and one piece 31 of the terminal plate 3 is connected to the semiconductor sensor unit 2. A base end 32a of the other piece 32 is bent in an L-shape, and the first side wall 1 of the housing 1 at a position where the base end 32a is extended.
The surface of the first side wall 11a of the housing 1 and the surface of the base portion 32a are housed in the notch groove 11b provided in the housing 1a, and form the same plane. Then, the cover 4 is fitted to the four side walls 11 of the housing 1 and sealed with the four side walls 11 with an adhesive. At this time, the cover 4 is attached to the first side wall 1.
1a and the other piece 32 form the same plane, so that the first
It is sealed to the side wall of the housing 1 without forming a gap with the side wall 11a.

Next, the pin insertion hole 14 is primarily sealed with a sealing material 14a made of an adhesive.
The organic gas generated from 4a and remaining in the box-shaped interior 12 is degassed from the sealing hole 43a provided in the cover bottom portion 41, and the sealing hole 43a is melted by a thermocompression bonding method to perform secondary sealing. In this way, the box-shaped interior 12 is sealed from the outside to prevent moisture from entering from outside.

The operation of the above will be described. When the acceleration is applied, the weight portion is displaced in a direction opposite to the direction in which the acceleration is applied, and the bending portion bends. The value changes. By measuring the resistance value of the piezoresistor, triaxial acceleration is detected.

The weight portion contacts the first contact surface of the first stopper 22 when excessive acceleration is applied, and contacts the second contact surface when excessive acceleration in the opposite direction is applied. Touch That is, the first stopper 22 and the second stopper 23 prevent the bending of the bending portion from being equal to or more than a certain value, and prevent the bending of the bending portion.

In the semiconductor acceleration sensor according to the embodiment, as described above, the notch grooves 11 b having a groove depth corresponding to the predetermined plate thickness δ of the other piece 32 are formed on both the first and second sides of the housing 1. When the base end portion 32a of the other piece 32 is received in the cutout groove 11b, the cover 4 is formed on the side walls 11a, 11a because the first side wall 11a and the other piece 32 form the same plane. It is tightly sealed to the four side walls 11 of the housing 1 without forming a gap with the first side wall 11a, seals the box-shaped interior 12 from the outside, and reliably prevents moisture from entering from the outside. Thus, high reliability can be achieved without corroding the semiconductor sensor unit 2.

In the state where the pin insertion hole 14 is sealed with the sealing material 14a, the sealing hole 4 for sealing the box-shaped interior 12 is formed.
3a is provided on the bottom 13 of the cover 4, so that the pin insertion hole 14 is firstly sealed with the sealing material 14a, and then the sealing hole 43a is melted and secondarily sealed to form the sealing material 14a. The box-shaped interior 12 can be sealed from the outside without leaving the organic gas generated from the inside in the box-shaped interior 12.

In the present embodiment, the sealing hole 43a to be sealed is provided in the cover bottom 41 while the pin insertion hole 14 is sealed with the sealing material 14a. If the pin insertion hole 14 communicating with the piece 31 of the terminal plate 3 is not provided in the housing 1 without being integrally formed, the sealing hole 43a may not be provided in the cover bottom 41, and there is no limitation.

The base end 32a of the other piece 32 is connected to the first side walls 11 of the four side walls 11 of the housing 1 which face each other.
a, 11a, and the notch groove 11b is provided in each of the first side walls 11a, 11a. However, when the base end of the other piece is led out from one of the four side walls 11,
The cutout groove 11b is not limited as long as it is provided on one side wall, that is, at least one side wall.

[0028]

According to the semiconductor acceleration sensor of the first aspect,
Since the cutout groove having a groove depth corresponding to the predetermined plate thickness δ of the other piece is provided on the side wall of the housing, when the base end of the other piece is accommodated in the notch groove, the side wall and the other piece are Since the surfaces are flush with each other, the cover is tightly sealed to the side wall of the housing without forming a gap with the side wall, and the inside of the box is sealed from the outside, so that moisture from the outside can enter. Is reliably prevented, and high reliability can be achieved without corroding the semiconductor sensor portion.

According to a second aspect of the present invention, in addition to the effects of the first aspect, if the pin insertion hole communicating with one piece of the terminal plate is provided in the housing, the pin insertion hole is sealed. In the state sealed with the stopper, a sealing hole for sealing the inside of the box shape from the outside was provided at the bottom of the cover, so that the pin insertion hole was first sealed with the sealing material,
Next, the sealing hole is melted and secondarily sealed, so that the inside of the box can be sealed from the outside without leaving the organic gas generated from the sealing material in the inside of the box.

According to a third aspect of the present invention, in the method of sealing a semiconductor acceleration sensor, the notch provided on the side wall of the housing so that the base end of the other piece has a groove depth corresponding to a predetermined plate thickness δ of the other piece. Since the housing is housed in the groove and the cover is sealed to the side wall of the housing, the cover is sealed to the side wall of the housing without forming a gap with the side wall, the box-shaped interior is sealed from the outside, and the Thus, it is possible to realize a highly reliable semiconductor acceleration sensor without reliably infiltrating moisture, and without corroding the semiconductor sensor portion.

According to a fourth aspect of the present invention, in addition to the effect of the third aspect of the present invention, in addition to the effect of the third aspect, the housing is provided with a pin insertion hole communicating with one piece of the terminal plate. If the pin insertion hole is primarily sealed with a sealing material and the sealing hole provided at the bottom of the cover is sealed and secondarily sealed, the organic gas generated from the sealing material remains inside the box. Without this, the inside of the box can be sealed from the outside.

[Brief description of the drawings]

FIG. 1 is a side sectional view (XX section in FIG. 3) showing an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a side sectional view showing a conventional example (a sectional view taken along line YY in FIG. 6).

FIG. 5 is a front view of the same.

FIG. 6 is a plan view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 11 Four side wall (side wall) 11b Notch groove 12 Box-shaped interior 14 Pin insertion hole 14a Sealing material 2 Semiconductor sensor part 21 Sensor chip 3 Terminal board 31 One piece 32 Other piece 32a Base end part δ predetermined board thickness 4 Cover 41 Cover bottom 42 Side 43a Sealing hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naohiro Taniguchi 1048 Odakadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd.

Claims (4)

[Claims] 1. A housing having a substantially rectangular bottomed box shape having a side wall and a box-shaped interior, a semiconductor sensor portion provided with a sensor chip for detecting acceleration, and one piece and one piece thereof. It is formed in a long plate shape having another piece bent and formed in an L-shape, and one piece is connected to the semiconductor sensor portion and the base end of the other piece having a predetermined plate thickness is at least one of the housings. A plurality of terminal plates led out from the side wall, and a cover formed into a substantially bottomed box shape having a cover bottom and side portions and sealed to the side wall of the housing, and the inside of the box shape is sealed from the outside Wherein the housing has a groove depth corresponding to the predetermined plate thickness, and a cutout groove for accommodating a base end of the other piece is provided on the at least one side wall. A semiconductor acceleration sensor. 2. A housing according to claim 2, wherein a pin insertion hole communicating with one piece of said terminal plate is provided in said housing. 2. The semiconductor acceleration sensor according to claim 1, wherein a sealing hole for sealing is provided at the bottom of the cover. 3. A sealing method for sealing a semiconductor acceleration sensor according to claim 1, wherein the sealing method includes a piece and another piece bent from the one piece into a substantially L-shape. A piece of a plurality of terminal plates formed in the shape of a scale is connected to the semiconductor sensor portion, and a base end of another piece having a predetermined plate thickness is formed into a substantially rectangular bottom having a side wall and a box-shaped interior. A notch formed in at least one side wall of the housing having a groove depth corresponding to a predetermined plate thickness, the base end of each other piece being led out from at least one side wall of the box-shaped housing; A method of sealing a semiconductor acceleration sensor, wherein a side portion of a cover which is housed in a groove and has a substantially bottomed box shape having a cover bottom and side portions is sealed to a side wall of a housing. 4. A pin insertion hole communicating with one piece of the terminal plate is provided in the housing, the cover is sealed to a side wall of the housing, and the pin insertion hole is sealed with a sealing material. 4. The method according to claim 3, wherein sealing is performed, and a sealing hole provided in a bottom portion of the cover is sealed to secondarily seal the inside of the box shape. 5.