JP2003130748A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor that can miniaturize a body for accommodating a pressure sensor chip and an IC chip and can reduce a packaging area to a circuit board or the like. SOLUTION: The pressure sensor comprises a pressure sensor chip 1 having a semiconductor strain gauge, an IC chip 2 where an amplification circuit for amplifying the output signal of the pressure sensor chip 1 and a temperature- compensating circuit for compensating the temperature of the output signal are integrated, a body 10 in a rectangular parallelepiped shape whose one surface is open, and a cover 20 for blocking the one surface of the body 10. A step section 10b for making different the height of the pressure sensor chip 1 and that of the IC chip 2 is formed on an inner bottom surface 10a of the body 10. The height of the step section 10b is set to height for picking the IC chip 2 without providing any space for allowing a collet to enter between the pressure sensor chip 1 and the IC chip 2 while the pressure sensor chip 1 and the IC chip 2 are arranged by pinching the step section 10b on the inner bottom surface 10a in the body 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor.

[0002]

2. Description of the Related Art As a conventional pressure sensor, a pressure sensor chip having a semiconductor strain gauge, an amplifier circuit for amplifying an output signal of the pressure sensor chip, and a temperature compensation circuit for temperature compensating the output signal are integrated. It is known that an integrated IC chip, a rectangular parallelepiped body with one surface open and a pressure sensor chip and an IC chip attached to the inner bottom surface, and a cover closing the one surface of the body are known. There is. A cylindrical pressure introducing pipe is provided on the other surface of the body so that a pressure introducing hole is formed in a portion extending from the pressure introducing pipe to the inner bottom surface.

The body is made of a synthetic resin molded product which is integrally molded with the lead frame at the same time, and portions of the lead frame projecting from both side surfaces of the body are used as lead pieces (terminals for external connection). . by the way,
The pressure sensor chip and the IC chip are arranged side by side on the inner bottom surface of the body, and the pressure sensor chip and the IC chip are connected to a lead frame via a bonding wire and via a lead piece that is a part of the lead frame. Connected to an external circuit. Here, the lead piece is bent in the thickness direction of the body, and is connected to an external circuit by being mounted on a circuit board such as a printed circuit board on which a circuit pattern of the external circuit is formed.

[0004]

By the way, in the above-described pressure sensor of the conventional structure, the pressure sensor chip and the IC chip are mounted on the inner bottom surface of the body, but the inner bottom surface of the body is formed in a planar shape. As shown in FIG. 3, when the chip (pressure sensor chip or IC chip) A is attached to the inner bottom surface 10a of the body 10 by die bonding, a collet 3 for picking up the chip A is inserted between the pressure sensor chip and the IC chip. Since it is necessary to provide a gap, it is difficult to reduce the size of the body 10 in the direction in which both chips are arranged side by side, and there is a problem that the mounting area becomes large when the body 10 is mounted on a circuit board on which a circuit pattern of an external circuit is formed. Further, since the lead pieces project from both side surfaces of the body and are bent, there is a problem that the mounting area and the mounting height become large when mounted on the circuit board.

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a pressure sensor capable of downsizing a body accommodating a pressure sensor chip and an IC chip and reducing a mounting area on a circuit board or the like. To provide.

[0006]

In order to achieve the above object, the invention of claim 1 is a temperature sensor chip, an amplifier circuit for amplifying an output signal of the pressure sensor chip, and a temperature compensation for temperature compensating the output signal. An IC chip in which circuits are integrated, a box-shaped body with one surface opened, and a pressure sensor chip and an IC chip attached to the inner bottom surface,
A cover that closes the one surface of the body, and a step portion that makes the pressure sensor chip and the IC chip different in height from each other is formed on the inner bottom surface of the body. Since the pressure sensor chip and the IC chip are formed with a step portion having different heights, the step portion is sandwiched between the pressure sensor chip and the IC chip by die bonding to the inner bottom surface of the body. The pressure sensor chip and the IC can be mounted by picking up with a collet in the order of the chip to be mounted on the lower side part and the chip to be mounted on the higher side part across the step
Since it is not necessary to secure a space for the collet to enter between the chip and the chip, the body for accommodating the pressure sensor chip and the IC chip can be downsized, and the mounting area on the circuit board or the like can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the body is a synthetic resin molded product in which a convex portion is provided so as to project from an end surface of a peripheral wall, and the pressure is applied to a tip surface of the convex portion. Since the terminal pattern in which at least one of the sensor chip and the IC chip is electrically connected is formed, compared to the conventional case where the external connection terminal is formed by a part of the lead frame. The mounting area and mounting height can be reduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure sensor of this embodiment is shown in FIG.
As shown in FIG. 1, a pressure sensor chip 1 having a semiconductor strain gauge, an IC chip 2 in which an amplifier circuit for amplifying an output signal of the pressure sensor chip 1 and a temperature compensation circuit for performing temperature compensation of the output signal are integrated, A body 10 which is a rectangular parallelepiped (box-shaped) with an open (upper surface in FIG. 1) and which has a pressure sensor chip 1 and an IC chip 2 attached to an inner bottom surface 10a and is made of a synthetic resin molded product, and the one surface of the body 10 It is provided with a closed rectangular plate-shaped cover 20. Here, the body 10 and the cover 20 constitute a body. Further, a cylindrical pressure introducing pipe 17 is projectingly provided on the other surface of the body 10 (a lower surface in FIG. 1), and a pressure introducing hole 18 is formed in a portion extending from the pressure introducing pipe 17 to the inner bottom surface 10a. In the following description, the vertical direction is defined by using the vertical direction in FIG.

The pressure sensor chip 1 is a substrate (such as a silicon substrate) in which a plurality of semiconductor strain gauges (four for forming a bridge circuit) are formed on a diaphragm formed thinner than other portions. Semiconductor substrate,
A so-called SOI substrate having a buried oxide film formed in the middle in the thickness direction) and an insulating material (for example, glass) that is superposed and bonded to the substrate and has a thermal expansion coefficient substantially equal to that of the substrate.
And a pedestal of the body 10. The pedestal is formed with a pressure introducing hole penetrating through the front and back at a portion corresponding to the diaphragm. The pressure introducing hole is formed in the body 10.
Is in communication with.

The upper end surface of the peripheral wall 11 of the body 10 (the cover 2
As shown in FIGS. 1 and 2, a rectangular annular convex portion 13 that protrudes upward over the entire circumference is continuously and integrally provided on the 0-side end surface) 11a. Here, the convex portion 13
Is thinner than the peripheral wall 11 of the body 10 and is formed so that the outer peripheral surface is aligned with the outer peripheral surface of the peripheral wall 11 of the body 10. The peripheral portion of the cover 20 is in contact with the surface. The protruding size of the protrusion 13 is set to be larger than the thickness of the cover 20. The cover 20 is adhered to the body 10 with an adhesive material.

By the way, the pressure sensor chip 1 and the IC chip 2 are arranged along the longitudinal direction of the body 10 (left-right direction in FIG. 2), and in the lateral direction on the inner bottom surface of the body 10 (vertical direction in FIG. 2). ) Are formed with convex portions 16 protruding upward. Here, the protrusion size of the convex portion 16 from the inner bottom surface 10a of the body 10 is that the upper surface of the convex portion 16 is the upper surface of the pressure sensor chip 1 (the upper surface of the pad 1a).
And the upper surface of the IC chip 2 (upper surface of the pad 2a) are set (see FIG. 1). The convex portion 16 is continuously formed on the inner bottom surface 10 a of the body 10 and the inner peripheral surface of the peripheral wall 11.

In the above-mentioned rectangular annular convex portion 13, the side walls 13a, 13a along the longitudinal direction of the body 10 are made thicker than the side walls 13b, 13b along the lateral direction. On both side walls 13a, 13a of the convex portion 13, a plurality of terminal patterns 15 formed along the upper end surface and the inner side surface are respectively arranged in a row in the longitudinal direction of the body 11 (that is, the terminal pattern 15 has a pressure. Sensor chip 1 and I
They are arranged side by side along the direction of arrangement with the C chip 2). Each terminal pattern 15 extends to the upper surface of the convex portion 16 along the inner peripheral surface of the body 10, and one end of the pressure sensor chip 1 or the portion (connection portion) 15b formed on the upper surface of the convex portion 16 is formed. The other end of the bonding wire W connected to the IC chip 2 is bonded. put it here,
The body 10 in this embodiment is a three-dimensional wiring board (Mold) in which a plurality of terminal patterns 15 are formed on a synthetic resin molded product.
ed interconnected device (MID).

By the way, in this embodiment, a step portion 10b is formed on the inner bottom surface 10a of the body 10 so that the pressure sensor chip 1 and the IC chip 2 have different heights. Step 1
The height of 0b is such that there is a space for the collet between the pressure sensor chip 1 and the IC chip 2 in a state where the pressure sensor chip 1 and the IC chip 2 are arranged with the step portion 10b sandwiched on the inner bottom surface 10a of the body 10. The height may be set so that the IC chip 2 can be picked up by the collet without providing it. For example, the plane including the upper surface (front surface) of the pad 1a of the pressure sensor chip 1 and the upper surface of the pad 2a of the IC chip 2 ( The dimension between the plane including the (surface) is 0.2 to 1.8.
It may be set to about mm.

In the pressure sensor of this embodiment, however, the pressure sensor chip 1 has the step portion 10b formed on the inner bottom surface 10a thereof to make the pressure sensor chip 1 and the IC chip 2 different in height. Also, when the IC chip 2 is attached to the inner bottom surface 10a of the body 10 by die bonding, the chip (in this embodiment, the pressure sensor chip 1) is attached to a lower side portion of the inner bottom surface 10a with the step portion 10b interposed therebetween. The space between the pressure sensor chip 1 and the IC chip 2 is secured between the pressure sensor chip 1 and the IC chip 2 by picking up and mounting the chip (IC chip 2 in this embodiment) in this order on the higher side across 10b. Since it is not necessary, the body 10 can be downsized and the mounting area on a circuit board or the like can be reduced.

The body 10 has an upper end surface 1 of the peripheral wall 11.
1A is a synthetic resin molded product in which a convex portion 13 is provided so as to project, and a pressure sensor chip 1 and an IC are provided on the tip surface of the convex portion 13.
Since the terminal pattern 15 electrically connected to at least one side of the chip 2 is formed, when mounting on the circuit board on which the circuit pattern of the external circuit is formed, the tip end surface of the convex portion 13 of the terminal pattern 15 is mounted. Since the portion (terminal portion) 15a formed on the wiring board may be connected to the circuit pattern, the mounting area and the mounting height can be increased as compared with the conventional case where the external connection terminal is formed by a part of the lead frame. Can be made smaller.

[0016]

According to the first aspect of the present invention, a pressure sensor chip, an IC chip in which an amplifier circuit for amplifying an output signal of the pressure sensor chip and a temperature compensation circuit for temperature compensation of the output signal are integrated are provided. An open box-shaped body having a pressure sensor chip and an IC chip attached to the inner bottom surface and a cover closing the one surface of the body are provided, and the height of the pressure sensor chip and the IC chip is increased on the inner bottom surface of the body. Is formed by a stepped portion that is different in
Since the pressure sensor chip and the IC chip are formed with a stepped portion on the inner bottom surface of the body, the pressure sensor chip and the IC chip are attached to the inner bottom surface of the body by die bonding. A chip to be mounted on the lower side of the stepped part and a chip to be mounted on the higher side of the stepped part are picked up in this order with a collet to mount the space between the pressure sensor chip and the IC chip. Since it is not necessary to secure the size, there is an effect that the body can be downsized and the mounting area on the circuit board or the like can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the body is a synthetic resin molded product in which a convex portion is provided so as to project from an end surface of a peripheral wall, and the pressure is applied to a tip surface of the convex portion. Since the terminal pattern in which at least one of the sensor chip and the IC chip is electrically connected is formed, compared to the conventional case where the external connection terminal is formed by a part of the lead frame. There is an effect that the mounting area and the mounting height can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment.

FIG. 2 is a schematic plan view of the same as the above with a cover removed.

FIG. 3 is an explanatory diagram of a conventional assembly process.

[Explanation of symbols]

1 Pressure sensor chip 2 IC chip 10 body 10a inner bottom surface 10b step 11 Perimeter wall 13 convex 15 terminal pattern 17 Pressure introducing pipe 18 Pressure introduction hole 20 cover W bonding wire

Claims (2)

[Claims] 1. A pressure sensor chip, an IC chip in which an amplifier circuit for amplifying an output signal of the pressure sensor chip and a temperature compensating circuit for temperature compensating the output signal are integrated, and a box shape with one surface open. A body having a pressure sensor chip and an IC chip attached to the inner bottom surface thereof, and a cover closing the one surface of the body, and a step portion that makes the pressure sensor chip and the IC chip different in height from each other on the inner bottom surface of the body. A pressure sensor characterized by being formed. 2. The body is a synthetic resin molded product in which a convex portion is provided so as to project from an end surface of a peripheral wall, and a tip end surface of the convex portion has:
The pressure sensor according to claim 1, wherein a terminal pattern is formed in which at least one of the pressure sensor chip and the IC chip is electrically connected.