JPH05264379A - Semiconductor pressure detecting device - Google Patents

Abstract

PURPOSE:To prevent the breakage of the diaphragm section of a semiconductor pressure sensor. CONSTITUTION:Breakage of a pressure sensor chip 1 is prevent by providing a stopper 7 on the upper surface of the chip 1 so as to suppress the projecting deformation of a diaphragm 2 within certain limit. While the pressure resistance of a sensor is reduced when the sensitivity of the sensor is increased, the pressure resistance of the high-sensitivity sensor can be improved by providing a stopper on the upper surface of its pressure sensor chip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure detecting device, and more particularly to a measure for preventing damage to a pressure sensor chip thereof.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional pressure sensor. In the figure, reference numeral 1 denotes a pressure sensor chip for converting pressure into an electric signal, and a diaphragm portion 2 formed by etching for sensing pressure. Have. A pedestal 3 supports the pressure sensor chip 1 and is placed on a substrate (header) 4 to relieve stress from the substrate.

In order to increase the sensitivity of the pressure sensor chip in the above structure, there is a method of reducing the thickness of the diaphragm or increasing the area of the diaphragm. Here, when the pressure P is applied from the pipe portion 5, the most stress is generated on the outer periphery of the diaphragm, and particularly the stress from the center of the diaphragm to the outer periphery is large,
The value can be represented by the formula of O ² = 3Pr ² / 4h ² . Here, P is the pressure, r is the radius, and h is the diaphragm thickness. If this stress is 3 × 10 ⁶ dyn / m ² or more, the silicon will be damaged.

[0004]

Since the conventional semiconductor pressure sensor is constructed as described above, when making a highly sensitive pressure sensor, the thickness of the diaphragm must be reduced or the diameter of the diaphragm must be increased. Therefore, there is a problem that the silicon chip is damaged even by a small pressure.

The present invention has been made in order to solve the above problems, and an object thereof is to prevent damage even if a pressure for damaging a silicon chip is applied.

[0006]

SUMMARY OF THE INVENTION A semiconductor pressure detecting device according to the present invention, when pressure is applied to a diaphragm portion of a pressure sensor chip, so that the diaphragm is not further deformed with respect to a certain pressure or more, A stopper having a recess is provided on the upper surface of the chip.

[0007]

The stopper according to the present invention suppresses the stress that causes damage to the pressure sensor chip.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 5 show the same or corresponding parts as in FIG. 3, and 6 is a stopper joined on the diaphragm portion 2 of the pressure sensor chip 1, which uses Pyrex glass, and the central portion of this stopper is shown. A concave portion 7 having a depth of several μ and a ventilation hole 8 are provided in the. By using anodic bonding for this bonding, it is not necessary to control the bonding thickness.

In the above structure, even if the diaphragm 2 is deformed into a convex shape due to the pressure applied from the pipe portion 5, the stopper 6 prevents the diaphragm 2 from being deformed to a certain degree or more and prevents the diaphragm from being damaged. it can.

FIG. 2 shows another embodiment of the present invention, in which silicon is used for the stopper 6, solder bumps 9 are bonded to the lower surface of the stopper 6, and the height of the bump is adjusted to adjust the pressure sensor chip. The distance between the stopper 1 and the stopper 6 can be easily controlled. For example, the larger the bump diameter, the higher the bump diameter, and the smaller the bump diameter, the lower the bump diameter. A silicon stopper provided with a solder bump having a certain height is attached to the pressure sensor chip.

In the above structure, when pressure is applied from the pipe portion, the diaphragm of the pressure sensor chip has a convex shape, but does not deform more than a certain amount.

[0012]

As described above, according to the present invention, there is an effect that the reliability of the semiconductor pressure detecting device can be greatly improved with a simple structure.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional semiconductor pressure detecting device.

[Explanation of symbols]

 1 Pressure Sensor Chip 2 Diaphragm 3 Pedestal 4 Header 5 Pipe 6 Stopper 7 Recess 9 Bump

Claims (3)

[Claims] 1. A semiconductor pressure detecting device comprising: a pressure sensor chip having a thin diaphragm portion; a pedestal that is joined to the pressure sensor chip to relieve stress from the outside; and a substrate on which the pedestal is mounted. A semiconductor pressure detecting device characterized in that a diaphragm damage preventing stopper having a recess having a predetermined depth formed in the central portion is provided on the upper surface of the diaphragm portion of the pressure sensor chip. 2. The semiconductor pressure detecting device according to claim 1, wherein Pyrex glass is used for the stopper, and the pressure sensor chip is anodically bonded. 3. A semiconductor pressure detecting device comprising: a pressure sensor chip having a thin diaphragm portion; a pedestal that is joined to the pressure sensor chip to relieve external stress; and a substrate on which the pedestal is mounted. A semiconductor pressure detecting device characterized in that a silicon stopper having solder bumps of a predetermined height bonded to an outer peripheral portion of a lower surface is provided on an upper surface of a diaphragm portion of the pressure sensor chip.