JP2771923B2 - 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 semiconductor pressure sensor.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing an example of a conventional semiconductor pressure sensor, and FIG. 6 is a sectional view showing an example of a pressure sensor chip in a conventional semiconductor pressure sensor.

In FIG. 1, reference numeral 1 denotes a pressure sensor chip. This pressure sensor chip 1 has a wafer 1a in which a strain gauge resistor is diffused and formed on the surface, an electrode 1b is formed, and a concave portion 1c is formed on the back surface. (For example,
A silicon single crystal plate) and a glass substrate 2 (for example, Pyrex glass) are formed by anodic bonding in a vacuum chamber. . Reference numeral 3 denotes a lead frame. The lead frame 3 is formed with a lead leg 3a for bonding to the outside, and the lead leg 3a is formed so as to facilitate mounting.

[0004] 4 is a lower case for housing the pressure sensor chip 1, 5 is a cylindrical upper case, 6 is a wire made of a thin metal wire for electrically connecting the electrode 1 b and the lead frame 3,
7, a gel for protecting the pressure sensor chip 1 and the wire 6; 8, a resin for bonding and fixing the pressure sensor chip 1 to the lead frame 3; 9, a resin for bonding and fixing the lead frame 3 to the lower case 4; A resin for bonding and fixing the frame 3 between the lower case 4 and the upper case 5; 11, a thick film substrate as a mounting substrate constituting a hybrid integrated circuit;
Denotes a component mounted on the thick film substrate 11, and 13 denotes a lead leg for extracting a signal to the outside.

In the conventional semiconductor pressure sensor configured as described above, when a pressure change of the external atmosphere is applied to the pressure sensor chip 1 through the opening of the upper case 5, the diaphragm is deformed, and the pressure is changed to the gauge resistance portion. Distortion occurs. For this reason, a large change occurs in the gauge resistance due to the piezoresistance effect, and a change in pressure is taken out as a change in the resistance value of the strain gauge.

Next, a method of manufacturing the above-described conventional semiconductor pressure sensor will be described with reference to FIGS. First, a resin 8 is applied to a portion of the lead frame 3 that holds the pressure sensor chip 1, the pressure sensor chip 1 is placed, and the resin 8 is cured by heating.
Adhesively fixed. Then, the electrode 1 of the pressure sensor chip 1
b and the lead frame 3 are connected by wires 6. Next, a resin 9 is applied to the bottom surface of the lower case 4, the pressure sensor chip 1 bonded and fixed to the lead frame 3 is housed, the upper case 5 is further covered, and the resin 10 is placed between the lower and upper cases 4 and 5. After the application, the resins 9 and 10 are cured by heating. Here, the lead frame 3 is sandwiched and fixed between the lower case 4 and the upper case 5 by the resin 10, and the back surface of the lead frame 3 holding the pressure sensor chip 1 is formed by the resin 9 on the bottom surface of the lower case 4. Adhesively fixed.

Further, a gel 7 is injected from the opening of the upper case 5 and cured by heating, so that the pressure sensor chip 1, the wires 6 and the like are protected from the external atmosphere as shown in FIG. Therefore, the lead feet 3a of the lead frame 3 are formed to form a structure that is easy to mount as shown in FIG. Finally, it is mounted on the thick film substrate 11 together with the other mounting components 12, and is mounted by soldering. After that, various characteristic tests are performed, the lead legs 13 of the external drawer are attached, and the assembly is completed.

[0008]

Since the conventional semiconductor pressure sensor is constructed as described above, the number of assembling steps is increased, and inspection is required in each assembling step, and the occurrence of defects increases. However, there has been a problem that operability and reliability of assembly are reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an inexpensive, highly reliable and small semiconductor pressure sensor which can reduce the number of assembly steps.

[0010]

A semiconductor pressure sensor according to the present invention is obtained by mounting a pressure sensor chip formed by anodically bonding a wafer on which a strain gage resistor is diffusely formed and a glass substrate to a mounting substrate. For semiconductor pressure sensors, bumps for electrical connection are formed on the surface of the pressure sensor chip
Of the pressure sensor chip surface
A bump for vibration-proof reinforcement is formed in a non-existing portion, and the electrical connection bump and the bump for vibration-proof reinforcement are solder-bonded to directly mount the pressure sensor chip on a mounting substrate.

[0011]

According to the present invention, since the electrical connection bump is formed on the surface of the pressure sensor chip and the electrical connection bump is soldered and the pressure sensor is directly mounted on the mounting substrate, the pressure sensor chip is provided. Conventionally, wires and lead frames required for electrical connection with the mounting board are not required, so that the number of parts is reduced, the number of assembly steps is reduced, and the reliability is improved. In addition,
Vibration resistance on electrically unaffected areas on the surface of the force sensor chip
Form a bump for reinforcement and mount this bump for vibration resistance
Because it is soldered to the board, vibration resistance is improved and high reliability
Property is obtained.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a sectional view of a semiconductor pressure sensor showing one embodiment of the present invention, and FIGS. 2 and 3 are a perspective view and a sectional view of a pressure sensor chip in one embodiment of the present invention, respectively. The same or corresponding parts as those of the conventional semiconductor pressure sensor shown in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted.

Referring to FIG. 1, reference numeral 20 denotes a pressure sensor chip. The pressure sensor chip 20 has a strain gauge resistor diffused and formed on the surface, a signal lead-out wiring 20b is formed, and a recess 20c is formed on the back surface. The wafer 20a (for example, a silicon single crystal plate) and the glass substrate 2 (for example, Pyrex glass) are anodically bonded in a vacuum chamber. The part is a diaphragm. Reference numeral 21 denotes a bump for electrical connection formed at the end of the wiring 20b. Reference numeral 22 denotes a wafer 20a for reinforcing the vibration resistance because the pressure sensor chip 20 is formed by bonding the extremely heavy glass substrate 2 to the wafer 20a. Bumps formed on portions of the surface of the substrate which are not electrically affected, 23
Is the case.

Next, the manufacturing method of the above embodiment will be described with reference to FIG. First, a solder paste is printed on the thick film substrate 11 on which a circuit pattern (not shown) is formed. Then, the pressure sensor chip 20 and the other mounting parts 12 are mounted on the thick film substrate 11, and the bumps 21 and 22 and the electrode portions on the thick film substrate 11 are soldered by solder reflow or the like. 20 and other mounting components 12 are mounted on the thick film substrate 11 at the same time. Next, cleaning is performed, and the thick film substrate 1 is housed so as to accommodate the pressure sensor chip 20.
The case 23 is bonded and fixed on the top 1 with a resin. Finally,
Attach the lead feet 13 of the external drawer to complete the assembly.

Here, the operation of the semiconductor pressure sensor of the above embodiment operates in the same manner as the aforementioned conventional semiconductor pressure sensor. In order to prevent the pressure sensor chip 20 from malfunctioning due to dust or the like, a protective film is formed on the surface of the wafer 20a by coating.

As described above, according to the above embodiment, since the bump 21 for electrical connection is formed on the surface of the pressure sensor chip 20, the bump 21 and the electrode portion on the thick film substrate 11 are soldered. As a result, the pressure sensor chip 20 can be directly mounted on the thick film substrate 11, and the number of assembly steps can be greatly reduced. Further, the wires 6 and the lead frame 3 which are conventionally required for the electrical connection between the pressure sensor chip 20 and the thick film substrate 11 become unnecessary, and the number of parts can be reduced. Therefore, assembling workability is improved, cost is reduced, high reliability is obtained, and downsizing is achieved.

Since bumps 22 for reinforcing vibration resistance are formed on the surface of the pressure sensor chip 20, the wafer 20a
Has improved vibration resistance and high reliability can be obtained.

[0018]

As described above, according to the present invention, a semiconductor pressure sensor having a pressure sensor chip formed by anodically bonding a wafer on which a strain gage resistor is formed by diffusion and a glass substrate is mounted on a mounting substrate. In the above, a bump for electrical connection is formed on the surface of the pressure sensor chip ,
Vibration-proof reinforcement of parts of the sensor chip surface that are not electrically affected
Bumps for electrical connection and vibration resistance
Since the pressure sensor chip is directly mounted on the mounting board by soldering the heavy use bumps , wires and lead frames, which were conventionally required for electrical connection between the pressure sensor chip and the mounting board, are no longer necessary, and parts The number of points is reduced, the number of assembly steps is reduced, the cost is reduced, the vibration resistance is improved,
There is an effect that the reliability is improved and the size is reduced.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing one embodiment of a pressure sensor chip in the semiconductor pressure sensor of the present invention.

FIG. 3 is a sectional view showing one embodiment of a pressure sensor chip in the semiconductor pressure sensor of the present invention.

FIG. 4 is an exploded perspective view of a semiconductor pressure sensor showing one embodiment of the present invention.

FIG. 5 is a sectional view showing an example of a conventional semiconductor pressure sensor.

FIG. 6 is a sectional view showing an example of a pressure sensor chip in a conventional semiconductor pressure sensor.

FIG. 7 is an exploded perspective view of a conventional semiconductor pressure sensor.

FIG. 8 is a sectional view of a manufacturing process of a conventional semiconductor pressure sensor.

FIG. 9 is a sectional view showing a manufacturing process of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 2 Glass substrate 11 Thick film substrate (mounting substrate) 20 Pressure sensor chip 20a Wafer 21 Bump (Bump for electrical connection)

Claims (1)

(57) [Claims] 1. A semiconductor pressure sensor in which a pressure sensor chip formed by anodically bonding a wafer on which a strain gage resistor is diffusely formed and a glass substrate is mounted on a mounting substrate. Connection bump
Forming and electrically connecting the surface of the pressure sensor chip.
A vibration-proof reinforcing bump is formed at a portion that does not affect the above, and the pressure sensor chip is directly mounted on the mounting board by soldering the electrical connection bump and the vibration-proof reinforcing bump. Semiconductor pressure sensor.