JPH11258094A - Electrostatic capacity type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized electrostatic capacity type pressure sensor having high reliability and low cost. SOLUTION: A sensor chip 30 is connected to the pedestal 40 on a silicon substrate side, and a movable electrode 11 and a fixed electrode 21 and a movable electrode pad 23 and a fixed electrode pad 22 for respectively connecting the electrodes are formed on a glass substrate 20 opposite to lead terminals 44, 45 to be directly connected to a lead terminal 44 and a lead terminal 45. Direct connection of the electrodes in the sensor chip 30 with the lead terminals in a package miniaturizes the package and improves joint reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type pressure sensor used for detecting pressure of a fluid.

[0002]

2. Description of the Related Art Generally, a pressure sensor as shown in FIG. 2 is known as this type of capacitance type pressure sensor. 2A and 2B are explanatory views of the capacitance type pressure sensor. FIG. 2A is a cross-sectional view of the sensor, and FIG. 2B is an external perspective view of the sensor with a cap removed to expose the inside.

In the capacitance type pressure sensor shown in FIG. 2, a diaphragm 11 functioning as a movable electrode which is deformed according to a differential pressure is formed on a silicon substrate 10 and a glass substrate 20 which is an insulating substrate is provided on a silicon substrate 10. A fixed electrode 21 is formed.

[0004] The silicon substrate 10 and the glass substrate 20
At the outer peripheral portion, anodic bonding is performed at a temperature of 350 ° C. to 450 ° C., whereby a cavity 12 is formed below the diaphragm 11.

A silicon substrate 10 and a glass substrate 20
The sensor chip 30 is provided with a fixed electrode lead-out lateral hole 13, through which the fixed electrode 21 formed on the glass substrate 20 passes through the fixed electrode lead-out fixed electrode pad 22 through the cavity 12. Pulled out.

A movable electrode 11 also having a diaphragm function
Passes through the silicon substrate 10 and is pressed against the movable electrode pad 23 provided on the glass substrate 20, and the cavity 1
It is taken out of 2.

[0007] The sensor chip 3 thus configured
0 is bonded on a base 40 as a base member. The pedestal 40 is provided with lead terminals 44 and 45. The lead terminals 44 and 45 are
Fixed electrode pad 22 and movable electrode pad 23 connected to fixed electrode 21 on lead wire 33 and lead wires 33 and 3
4 are electrically connected to each other.

[0008] Atmospheric pressure introduction holes 31 and 43 are formed in the glass substrate 20 and the pedestal 40, respectively, and these two atmospheric pressure introduction holes 31, 43 are communicated with each other. Further, the fixed electrode lead-out lateral hole 13 is sealed by a sealant 32 in order to isolate the cavity portion 12 from the pedestal region 47 outside the sensor chip 30.

Further, the pedestal 40 and the cap 41 as a cover member provided with the measured pressure introducing hole 42 are sealed with a hermetic seal to form a capacitance type pressure sensor.

[0010]

However, in the conventional capacitance type pressure sensor, the fixed electrode pad 22 and the movable electrode pad 23 of the sensor chip 30 are connected to the lead terminals 44 and 45 in the pedestal 40, the lead wires 33 and Since the electrical connection was made using the wiring 34, a connection area for the lead wires 33 and 34 was required on the glass substrate 20,
There is a problem that the size is increased. Further, there is a problem that the wire is cut at the time of manufacturing the sensor and at the time of long-term reliability.

Accordingly, the present invention eliminates such disadvantages,
The fixed electrode pad and the movable electrode pad in the sensor chip are directly connected to the lead terminals, respectively, to reduce the size. Also, by using no lead wire, a highly reliable, low-cost static junction can be obtained. An object of the present invention is to provide a capacitance type pressure sensor.

[0012]

According to the present invention, a fixed electrode pad and a movable electrode pad formed on a silicon substrate of a sensor chip and a lead terminal in a pedestal are directly used by using solder or a conductive adhesive. A bonded capacitive pressure sensor is obtained.

That is, the present invention includes an insulating substrate on which a fixed electrode is formed, and a silicon substrate on which a movable electrode having a diaphragm function that is deformed in response to a differential pressure is formed. And a sensor chip that forms a cavity by joining the insulating substrate and the silicon substrate so that they oppose each other with a gap therebetween,
The gap length is changed according to the differential pressure of the fluid on both sides of the movable electrode having the diaphragm function, and the pressure is detected by the change in the capacitance between the movable electrode and the fixed electrode due to the change in the gap length. A capacitive pressure sensor, wherein the movable electrode and the fixed electrode and the movable electrode pad and the fixed electrode pad connecting the movable electrode and the fixed electrode are formed on the insulating substrate so as to face the lead terminals.
This is a capacitance type pressure sensor in which a movable electrode pad and a fixed electrode pad are connected to the lead terminals.

Further, the present invention is a capacitance type pressure sensor wherein the sensor chip is connected to a pedestal on the silicon substrate side of the sensor chip.

According to the present invention, by directly connecting each electrode in the sensor chip to the lead terminal in the package, the size of the package can be reduced and the reliability in bonding can be improved.

Further, since the sensor chip is connected to the package on the silicon substrate side, there is no need to seal the fixed electrode lead-out lateral holes with a sealant as in the conventional sensor, and the sensor chip has a glass substrate. Since there is no need to form an atmospheric pressure introducing hole in the inside, the number of manufacturing steps is reduced, the material cost can be reduced, and a low-cost capacitive pressure sensor can be obtained.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a capacitance type pressure sensor according to an embodiment of the present invention.

FIG. 1 is an explanatory diagram of a capacitance type pressure sensor according to the present invention. FIG. 1A is a sectional view of a capacitance type sensor according to the present invention, and FIG. 1B is a perspective view showing the sensor with its cap removed to expose the inside.

The description of the configuration of the capacitance type pressure sensor of the present invention will be omitted for the parts substantially similar to those of the prior art described with reference to FIG. Only the package part will be described in detail.

As shown in FIG. 1, the movable electrode pad 23 and the fixed electrode pad 22 arranged on the glass substrate 20 of the sensor chip 30 are connected to lead terminals 44 in a pedestal 40 having a pressure introduction hole 42 to be measured. 45 and are arranged.

The movable electrode pad 23 and the lead terminal 44, and the fixed electrode pad 22 and the lead terminal 45 are electrically connected directly by a conductive bonding agent 24 such as solder or a conductive adhesive.

As a result, the conventional connection area of the wire can be removed, and since no wire is used, the joining reliability is improved.

The sensor chip 30 has the silicon substrate 10 adhered to the pedestal 40 with an adhesive 25 such as silicone rubber, and the pressure applied through the measured pressure introducing hole 42 is applied to the movable electrode (diaphragm part) 11. Become like

Therefore, it is not necessary to separate the cavity portion 12 from the pedestal region 47 outside the sensor chip and seal the fixed electrode lead-out lateral hole 13 with a sealant as in the prior art.

Further, since the fixed electrode lead-out lateral hole 13 can be used as an atmospheric pressure introducing hole, it is not necessary to provide an atmospheric pressure introducing hole in the glass substrate 20 as in the conventional case, and the number of manufacturing steps and material costs are greatly reduced. Can be reduced. Note that the atmospheric pressure introduction hole 43 is disposed in the cap 41.

[0026]

As described above, according to the present invention, a highly reliable and low-cost capacitive pressure sensor having a reduced size can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a capacitance type pressure sensor according to an embodiment of the present invention. FIG. 1A is a sectional view. FIG. 1B is a perspective view showing the inside thereof exposed.

FIG. 2 is an explanatory view of a conventional capacitance type pressure sensor. FIG.
(A) is sectional drawing. FIG. 2B is a perspective view showing the inside thereof exposed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Silicon substrate 11 Movable electrode (or diaphragm part) 12 Cavity part 13 Horizontal hole for leading out fixed electrode 20 Glass substrate 21 Fixed electrode 22 Fixed electrode pad 23 Movable electrode pad 24 Conductive bonding agent 25 Adhesive 30 Sensor chip 31 Atmospheric pressure introduction hole 32 Sealant 33,34 Lead wire 40 Pedestal 41 Cap 42 Measured pressure introducing hole 43 Atmospheric pressure introducing hole 44,45 Lead terminal 47 Area in pedestal

Claims (2)

[Claims] An insulating substrate on which a fixed electrode is formed; and a silicon substrate on which a movable electrode having a diaphragm function that is deformed in response to a pressure difference is formed, wherein a gap is formed between the movable electrode and the fixed electrode. As opposed to each other
A sensor chip for joining the insulating substrate and the silicon substrate to form a cavity, wherein the gap length is changed according to a pressure difference between fluids on both sides of the movable electrode having the diaphragm function. A capacitance-type pressure sensor for detecting pressure by a change in capacitance between the movable electrode and the fixed electrode due to a change in the capacitance, wherein the movable electrode and the fixed electrode are fixed on the insulating substrate so as to face lead terminals. An electrostatic capacitance type pressure sensor wherein an electrode, a movable electrode pad and a fixed electrode pad connecting the electrode and the electrode are formed, and the movable electrode pad and the fixed electrode pad are directly connected to the lead terminal. 2. The capacitance-type pressure sensor according to claim 1, wherein the sensor chip is connected to a pedestal on the silicon substrate side of the sensor chip.