JPH11337431A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor capable of preventing the spread of cracks which occur in a glass seating in a simple constitution. SOLUTION: A semiconductor pressure sensor is formed by joining a semiconductor 1 with a diaphragm 11 to a glass seating 2 in which a pressure inlet 21 for introducing pressure to the diaphragm 11 is formed and by joining the surface of the glass seating 2 on the opposite side to the joint surface with the semiconductor substrate 1 to a package 3 by soldering. In the semiconductor pressure sensor, a plurality of notches 24 are formed in the vicinity of the joint surface between the glass seating 2 and the package 3 and of the pressure inlet 21.

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 in which a semiconductor substrate having a diaphragm and a package are joined via a glass pedestal.

[0002]

2. Description of the Related Art In recent years, pressure sensors have been used in various industrial fields. Above all, the use of semiconductor pressure sensors has been rapidly increasing in the field of vehicle-mounted devices, home electric appliances, and the like in terms of reliability, cost, and reduction in size and weight.

As shown in FIG. 4, this semiconductor pressure sensor has a structure in which a piezoresistor 12 is formed on one surface of a silicon chip (semiconductor substrate) 1 on which a diaphragm 11 is formed. This silicon chip 1 is bonded to a package 3 via a glass pedestal 2. The silicon chip 1 and the glass pedestal 2 are joined by anodic bonding, and the surface of the glass pedestal 2 on the side opposite to the joining surface with the silicon chip 1 and the package 3 are soldered with the solder 5 by the solder 5 via the metallization layer 4. Have been. By these bondings, physically strong bonding can be obtained. In addition, glass pedestal 2
Is formed with a pressure introduction hole 21 for introducing pressure to the diaphragm 11.

[0004] Such a semiconductor pressure sensor has a problem in mechanical strength required for a joint portion between the glass pedestal 2 and the solder 5 at the time of solder brazing. That is, the solder brazing used for joining the glass pedestal 2 and the package 3 is 20
Since the bonding technique is performed by heat treatment at 0 ° C. to 300 ° C., when applied to the assembly of a semiconductor pressure sensor, the stress generated by the difference in the thermal expansion coefficient between the glass pedestal 2 and the solder 5 causes the glass pedestal to undergo pressure application. Cracks occur in the vicinity of the pressure introduction holes 21 of the glass pedestal 2
Is destroyed, and as a result, the silicon chip 1 is destroyed.

In order to improve such a problem, a configuration disclosed in Japanese Patent Application Laid-Open No. 9-101219 has been proposed.
In other words, as shown in FIG. 5A, by forming the notch 22 near the pressure introduction hole 21 on the joint surface of the glass pedestal 2 with the package 3, the vicinity of the pressure introduction hole 21 of the glass pedestal 2 is formed. Cracks can be prevented. Further, as shown in FIG. 5B, the occurrence of cracks can be prevented by the tapered notch 23.

[0006]

However, in the above-described semiconductor pressure sensor, notches 22 and 23 having a certain size are provided in order to prevent the occurrence of cracks.
Therefore, there is a problem that it takes time to form the notches 22 and 23 and it is difficult to form the notches 22 and 23 in the shape.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor pressure sensor capable of preventing the transmission of cracks generated on a glass pedestal with a simple structure. It is in.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor pressure sensor in which a semiconductor substrate having a diaphragm is joined to a glass pedestal having a pressure introducing hole for introducing pressure into the diaphragm. In a semiconductor pressure sensor formed by soldering a package and a surface opposite to a bonding surface of the pedestal to the semiconductor substrate, a plurality of notches are provided on a bonding surface of the glass pedestal with the package and near the pressure introducing hole. It is characterized by having been formed.

According to a second aspect of the present invention, there is provided the semiconductor pressure sensor according to the first aspect, wherein the glass pedestal is formed by joining the same kind of glass plates, and the joining surface of the glass plates and the pressure introducing hole are provided. A plurality of notches are also formed in the vicinity of.

According to a third aspect of the present invention, there is provided a semiconductor pressure sensor according to the first aspect, wherein the glass pedestal is formed by joining different kinds of glass plates, and is formed on a joining surface of the glass plates and a pressure introducing hole. A plurality of notches are also formed in the vicinity of.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process chart showing a semiconductor pressure sensor and a method for manufacturing the same according to a first embodiment of the present invention.

The semiconductor pressure sensor of the present embodiment firstly
As shown in FIG. 1A, a glass pedestal 2 having a polished surface
After the pressure introduction hole 21 is formed at a predetermined position by ultrasonic processing or the like, patterning is performed using the mask material 6 having a plurality of slits 61 formed in the vicinity of the pressure introduction hole 21, and the vicinity of the pressure introduction hole 21 is formed by etching. Multiple notches 2
4 is formed. These treatments are performed, for example, by using a urethane-based resin for the mask material 6 and by a sandblasting method using silicon carbide or alumina abrasive grains. At this time,
By setting the patterning and etching process,
Combination of wet etching and dry etching,
By combining isotropic etching and anisotropic etching, a plurality of notches 24 can be formed in many directions.

Next, as shown in FIG. 1B, a metallized layer 4 is formed on the surface of the glass pedestal 2 where the notch 24 is formed by a sputtering method or a vapor deposition method.

Next, as shown in FIG. 1 (c), a silicon chip (semiconductor substrate) in which a piezoresistor 12 is formed on one surface by diffusion and a concave portion is formed on the other surface to form a diaphragm 11 is formed. 1) A voltage (1000 V) is applied between 1 and the surface of the glass pedestal 2 where the metallized layer 4 is not formed.
Is applied by anodic bonding.

Next, as shown in FIG. 1D, the surface of the glass pedestal 2 on which the metallized layer 4 is formed and the package 3 are soldered at 200 ° C. to 300 ° C. using solder 5. By joining, the semiconductor pressure sensor is completed.

According to the semiconductor pressure sensor of this embodiment,
Since a plurality of notches 24 are formed on the joint surface of the glass pedestal 2 with the package 3 and in the vicinity of the pressure introducing hole 21, the propagation of cracks in the vicinity of the pressure introducing hole 21 of the glass pedestal 2 is reduced by a plurality of cuts. Since the glass pedestal 2 is dispersed by the notch 24, breakage of the glass pedestal 2 is prevented. Further, by forming the plurality of notches 24 in multiple directions, the effect of dispersing cracks can be further enhanced.

FIG. 2 is a sectional view showing a schematic configuration of a semiconductor pressure sensor according to a second embodiment of the present invention.

The semiconductor pressure sensor of the present embodiment is the same as the semiconductor pressure sensor of the first embodiment, except that the same type of glass plates 2a and 2b are joined to form a glass pedestal 2. This bonding is performed by, for example, anodic bonding via a metal. A plurality of notches 24 are formed near the pressure introducing holes 21 on the surface of the glass plate 2b on which the metallized layer 4 is formed. Also, a plurality of notches 25 are formed near the pressure introduction holes 21 on the joining surfaces of the glass plates 2a and 2b. Here, it is better to make the thickness of the glass plate 2b on the package 3 side as thin as possible.

According to the semiconductor pressure sensor of this embodiment,
In contrast to the first embodiment, the transmission of cracks generated near the pressure introduction hole 21 of the glass pedestal 2 is
The particles can be further dispersed by the cutouts 25 formed in the joint surfaces a and 2b.

FIG. 3 is a sectional view showing a schematic configuration of a semiconductor pressure sensor according to a third embodiment of the present invention.

The semiconductor pressure sensor according to the present embodiment is the same as the semiconductor pressure sensor according to the first embodiment, except that different kinds of glass plates 2c and 2d are joined to form a glass pedestal 2. For example, a glass plate having a relatively low strength is used for the glass plate 2d on the package 3 side. Different kinds of glass plates 2c, 2d
The bonding between them is performed by, for example, anodic bonding via a metal. A plurality of notches 24 are formed near the pressure introducing holes 21 on the surface of the glass plate 2d on which the metallized layer 4 is formed.
Is formed. Further, a plurality of notches 25 are also formed near the pressure introducing holes 21 on the joining surfaces of the glass plates 2c and 2d. Here, it is better to make the thickness of the glass plate 2d on the package 3 side as thin as possible.

According to the semiconductor pressure sensor of this embodiment,
In contrast to the first embodiment, the transmission of cracks in the vicinity of the pressure introduction hole 21 of the glass pedestal 2 is controlled by the glass plates 2a, 2b.
Can be further dispersed by the cutouts 25 formed in the joint surface of. Further, if a relatively weak glass plate is used as the glass plate 2b, the glass plate 2b serves as a cushioning material, and the effect of preventing crack transmission can be further enhanced.

[0023]

As described above, according to the first aspect of the present invention, a semiconductor substrate having a diaphragm and a glass pedestal having a pressure introduction hole for introducing pressure into the diaphragm are joined. In a semiconductor pressure sensor in which a package and a surface of a glass pedestal opposite to a surface to be bonded to the semiconductor substrate are solder-bonded, a plurality of notches are provided on a bonding surface of the glass pedestal with the package and near a pressure introducing hole. Formed, the transmission of cracks in the vicinity of the pressure introduction hole of the glass pedestal will be dispersed by a plurality of notches, and by a simple configuration of forming a plurality of notches, transmission of cracks will be prevented, A semiconductor pressure sensor capable of preventing the pedestal from being broken has been provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the glass pedestal is formed by joining the same type of glass plate, and is located on the joining surface of the glass plate and near the pressure introducing hole. Since a plurality of cutouts are formed, the propagation of cracks can be further dispersed by the cutouts formed on the joint surface of the glass plate.

According to a third aspect of the present invention, in the first aspect of the present invention, the glass pedestal is formed by joining different kinds of glass plates, and the joining surface of the glass plates and the vicinity of the pressure introducing hole. Since a plurality of cutouts are formed, the propagation of cracks can be further dispersed by the cutouts 25 formed on the joining surfaces of different kinds of glass plates, and a relatively weak glass plate on the package side is used. If so, the glass plate serves as a cushioning material, and the effect of preventing the transmission of cracks can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a manufacturing process of a semiconductor pressure sensor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a semiconductor pressure sensor according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a schematic configuration of a semiconductor pressure sensor according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a schematic configuration of a semiconductor pressure sensor according to a conventional example.

FIG. 5 is a sectional view showing a schematic configuration of a semiconductor pressure sensor according to another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon chip 2 Glass pedestal 2a-2d Glass pedestal 3 Package 4 Metallization layer 5 Solder 6 Mask material 21 Pressure introduction hole 24 Notch 25 Notch 61 Slit

Claims (3)

[Claims] 1. A semiconductor substrate having a diaphragm is joined to a glass pedestal having a pressure introduction hole for introducing pressure to the diaphragm, and a surface of the glass pedestal opposite to a joining surface with the semiconductor substrate. Pressure sensor, wherein a plurality of cutouts are formed in a bonding surface of the glass pedestal with the package and near the pressure introducing hole. 2. The glass pedestal is formed by joining the same kind of glass plates, and a plurality of cutouts are formed on the joining surface of the glass plates and also near the pressure introducing holes. 2. The semiconductor pressure sensor according to 1. 3. The glass pedestal is formed by joining different kinds of glass plates, and a plurality of cutouts are formed on the joining surface of the glass plates and also near the pressure introducing holes. 2. The semiconductor pressure sensor according to 1.