JPH05332863A - Semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To obtain a semiconductor pressure sensor, which can achieve the reduction in number of parts, reduction in assembling man-hours, the low cost and the improvement in reliability. CONSTITUTION:A pressure sensor chip 20 is constituted by bonding a wafer, can which a strain-gage resistor is diffused and formed, and a glass substrate by anode bonding. A bump 21 for electrical connection is formed on the surface of the chip. The pressure sensor chip 2 is directly mounted on a thick-film substrate 11 by bonding the electrode, which is formed on the thick-film substrate 11 constituting a hybrid integrated circuit, and the bump 21 with solder.

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 the conventional semiconductor pressure sensor.

In the figure, reference numeral 1 denotes a pressure sensor chip. The pressure sensor chip 1 has a surface on which a strain gauge resistor is diffused and an electrode 1b is formed, and a recess 1c is formed on the back surface of the wafer 1a. (For example,
A silicon single crystal plate) and a glass substrate 2 (for example, Pyrex glass) are anodically bonded in a vacuum chamber, the inside of the recess 1c is maintained at a vacuum to serve as a reference pressure, and the thin portion of the wafer 1a serves as a diaphragm. . Reference numeral 3 denotes a lead frame. The lead frame 3 is formed with lead legs 3a for joining to the outside, and the lead legs 3a are formed so as to facilitate mounting.

Reference numeral 4 is a lower case for accommodating the pressure sensor chip 1, 5 is a cylindrical upper case, and 6 is a wire made of a fine metal wire for electrically connecting the electrode 1b and the lead frame 3.
7 is a gel for protecting the pressure sensor chip 1 and the wire 6, 8 is a resin for adhesively fixing the pressure sensor chip 1 and the lead frame 3, 9 is a resin for adhesively fixing the lead frame 3 and the lower case 4, and 10 is a lead. 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, 12
Is a mounting component mounted on the thick film substrate 11, and 13 is a lead leg for extracting a signal to the outside.

In the conventional semiconductor pressure sensor thus configured, 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 gauge resistance portion is affected. Distortion occurs. Therefore, a large change occurs in the gauge resistance due to the piezo resistance effect, and the change in pressure is taken out as the change in the resistance value of the strain gauge.

Next, a method of manufacturing the above conventional semiconductor pressure sensor will be described with reference to FIGS. First, the resin 8 is applied to the 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, and the pressure sensor chip 1 is attached to the lead frame 3.
Adhesively fix. Then, the electrode 1 of the pressure sensor chip 1
b and the lead frame 3 are connected by a wire 6. Next, the resin 9 is applied to the bottom surface of the lower case 4, the pressure sensor chip 1 adhered 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 coating, the resins 9 and 10 are heat-cured. Here, the lead frame 3 is sandwiched between the lower case 4 and the upper case 5 by the resin 10 and adhesively fixed, and the back surface of the lead frame 3 holding the pressure sensor chip 1 is the bottom surface of the lower case 4 by the resin 9. It is fixed by adhesion.

Further, the gel 7 is injected from the opening of the upper case 5 and heat-cured to protect the pressure sensor chip 1, the wire 6 and the like from the external atmosphere, as shown in FIG. Therefore, the lead legs 3a of the lead frame 3 are formed into a structure that facilitates mounting as shown in FIG. Finally, it is mounted on the thick film substrate 11 together with other mounting components 12 and soldered to mount. 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 increases, inspection is required in each assembling step, and the occurrence of defects increases. However, there is a problem that assembly workability and reliability are reduced.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain an inexpensive and highly reliable small semiconductor pressure sensor which can reduce the assembly process.

[0010]

A semiconductor pressure sensor according to the present invention has a pressure sensor chip formed by anodic bonding a wafer on which a strained gage resistor is diffused and a glass substrate on a mounting substrate. In a semiconductor pressure sensor, bumps for electrical connection are formed on the surface of the pressure sensor chip, and the bumps for electrical connection are solder-bonded to directly mount the pressure sensor chip on a mounting substrate.

[0011]

According to the present invention, since the bumps for electrical connection are formed on the surface of the pressure sensor chip and the bumps for electrical connection are soldered to mount the pressure sensor directly on the mounting substrate, the pressure sensor chip is mounted. Since the wires and the lead frame, which have been conventionally required for electrical connection between the mounting board and the mounting board, are not required, the number of parts is reduced, the number of assembling steps is reduced, and the reliability is improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a semiconductor pressure sensor showing an embodiment of the present invention, and FIGS. 2 and 3 are perspective and sectional views of a pressure sensor chip according to an embodiment of the present invention. FIGS. The same or corresponding parts as those of the conventional semiconductor pressure sensor shown in FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 20 denotes a pressure sensor chip. The pressure sensor chip 20 has a strain gauge resistor diffused on the front surface thereof, a wiring 20b for signal extraction formed thereon, and a recess 20c formed on the rear surface thereof. The formed wafer 20a (for example, a silicon single crystal plate) and the glass substrate 2 (for example, Pyrex glass) are anodic-bonded in a vacuum chamber, and the inside of the recess 20c is maintained at a vacuum to serve as a reference pressure. The part is a diaphragm. Reference numeral 21 is a bump for electrical connection formed at the end of the wiring 20b, and reference numeral 22 is a wafer 20a for reinforcing the vibration resistance of the pressure sensor chip 20 because the pressure sensor chip 20 is formed by bonding a remarkably heavy glass substrate 2 to the wafer 20a. Bumps 23 formed on the surface of the
Is the case.

Next, the manufacturing method of the above embodiment will be described with reference to FIG. First, solder paste is printed and applied on the thick film substrate 11 on which a circuit pattern (not shown) is formed. Next, the pressure sensor chip 20 and the other mounting components 12 are placed on the thick film substrate 11, and the bumps 21 and 22 are solder-bonded to the electrode portions on the thick film substrate 11 by solder reflow or the like. 20 and other mounting components 12 are simultaneously mounted on the thick film substrate 11. Next, the thick film substrate 1 is washed so as to accommodate the pressure sensor chip 20.
The case 23 is adhesively fixed onto the top of the case 1 with resin. Finally,
Attach the lead legs 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 way as the conventional semiconductor pressure sensor described above. Further, in order to prevent the pressure sensor chip 20 from being defective due to dust or the like, a protective film is formed by coating on the surface of the wafer 20a.

As described above, according to the above embodiment, since the bumps 21 for electrical connection are formed on the surface of the pressure sensor chip 20, the bumps 21 and the electrode portions on the thick film substrate 11 are soldered and joined. Thus, the pressure sensor chip 20 can be directly mounted on the thick film substrate 11, and the number of assembling steps can be significantly reduced. Further, the wires 6, the lead frame 3, etc., which have been conventionally required for the electrical connection between the pressure sensor chip 20 and the thick film substrate 11, are not necessary, and the number of parts can be reduced. Therefore, assembling workability is improved, cost is reduced, high reliability is obtained, and size reduction is achieved.

Further, since the bumps 22 for reinforcing the vibration resistance are formed on the surface of the pressure sensor chip 20, the wafer 20a is formed.
The vibration resistance of is improved and high reliability is obtained.

[0018]

As described above, according to the present invention, a semiconductor pressure sensor in which a pressure sensor chip formed by anodic bonding a wafer on which strained gage resistors are diffused and a glass substrate are mounted on a mounting substrate. In the above, since the electrical connection bumps are formed on the surface of the pressure sensor chip and the electrical connection bumps are solder-bonded to mount the pressure sensor chip directly on the mounting board, the electrical connection between the pressure sensor chip and the mounting board is reduced. The wires and leadframes that were required in the past are no longer needed for the dynamic connection, the number of parts is reduced, the number of assembly steps is reduced, the cost is reduced, the reliability is improved, and the size is reduced. effective.

[Brief description of drawings]

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

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

FIG. 3 is a sectional view showing an 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 cross-sectional view of 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 (electrical connection bump)

Claims (1)

[Claims] 1. A semiconductor pressure sensor in which a pressure sensor chip formed by anodic bonding a wafer on which a strained gage resistor is diffused to a glass substrate is mounted on a mounting substrate. A semiconductor pressure sensor characterized in that a bump for connection is formed, the bump for electrical connection is soldered and the pressure sensor chip is directly mounted on the mounting substrate.