JPH10321874A - Semiconductor pressure sensor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor in which wire bonding for electrical connection between a circuit board and a sensor element is abolished and which enables miniaturization, and a method for manufacturing the same. SOLUTION: A sensor element 2 has a diaphragm 1, which is arranged on a glass stage 4 and adapted for detecting the pressure of a medium. A pressure lead-in hole 13 is formed on the surface of the glass stage 4 which faces the diaphragm 1. A circuit board 7 has a pressure lead-in portion 15 (throughhole) formed therein which faces the pressure lead-in hole 13, and a predetermined wiring pattern and a connection land 14 formed thereon. An electrode portion 12 is formed on the sensor element 2, so as to connect input and output of the sensor element 2 to the circuit board 7. The electrode portion 12 and the connection land 14 are connected to each other by soldering.

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 for detecting the pressure of a medium such as a gas and a liquid.

[0002]

2. Description of the Related Art There is a conventional semiconductor pressure sensor as shown in FIG. In this semiconductor type pressure sensor, a sensor element 2 forming a thin pressure receiving and straining diaphragm 1 of silicon single crystal, a pressure introducing hole 3 formed at a position corresponding to the diaphragm 1, and a thermal expansion coefficient After the sensor chip 5 is obtained by joining the glass pedestal 4 and the glass pedestal 4 having substantially the same values by the anodic bonding method, the pressure introduction hole 3 of the sensor chip 5 is formed on the circuit board 7 on which the pressure introduction section 6 for introducing the medium is formed. The sensor chip 5 is disposed so as to face the pressure introducing portion 6 of the circuit board 7, and the circuit board 7 and the sensor chip 5
And an adhesive, or a metallized layer is formed on the bottom surface of the glass pedestal 4, and the metallized layer and a connection land formed on the circuit board 7 are bonded via solder.

In order to detect the pressure by the sensor chip 5 and supply power to the sensor chip 5, an electrode 8 of the sensor element 2 and a land 9 of the circuit board 7 are connected to each other by a conductive member 10 such as gold or aluminum. A semiconductor pressure sensor is obtained by bonding and electrically connecting the sensor chip 5 and the circuit board 7.

[0004]

In the semiconductor pressure sensor having such a configuration, since the electrode portion 8 of the sensor element 2 and the land portion 9 of the circuit board 7 are wire-bonded one by one in a manufacturing process, mass production is considered. In this case, not only is the productivity low, but also the production cost is increased due to an increase in the number of wire bondings.

Further, since wire bonding is performed using a bonding tool, the distance between the electrode portion 8 and the land portion 9 cannot be set to be smaller than the width of the bonding tool, and this type of field requires a small space. At
There was a problem that it could not be miniaturized. The present invention focuses on the above problems, and provides a semiconductor pressure sensor that can be miniaturized while eliminating wire bonding for electrical connection between a circuit board and a sensor element, and a method of manufacturing the same.

[0006]

According to the present invention, there is provided a semiconductor pressure sensor for detecting the pressure of a medium such as a gas or a liquid, the glass pedestal being disposed on the glass pedestal. A sensor element forming a diaphragm for detecting the pressure of the medium, a circuit board on which a wiring pattern and a connection land are formed at a predetermined location, and an input / output of the sensor element are connected to the circuit board.
An electrode portion formed on the sensor element, wherein the electrode portion and the connection land are connected by soldering.

In a semiconductor type pressure sensor for detecting the pressure of a medium such as gas or liquid, a glass pedestal, a sensor element disposed on the glass pedestal and forming a diaphragm for detecting the pressure of the medium, A pressure introducing hole formed on a surface of the glass pedestal facing the diaphragm, a circuit board forming a through hole facing the pressure introducing hole, and a predetermined wiring pattern and a connection land formed thereon, and the sensor An electrode part formed on the sensor element for connecting input and output of the element to the circuit board, wherein the electrode part and the connection land are connected by soldering.

Further, a reinforcing adhesive member is applied around the connection portion by the solder and around the contact portion between the circuit board and the glass pedestal.

In a method of manufacturing a semiconductor pressure sensor for detecting a pressure of a medium such as a gas or a liquid, a groove forming step of forming a plurality of grooves having a predetermined shape on a surface of a glass substrate; A bonding step of bonding the silicon wafer on the glass substrate such that two or more diaphragms face each other via a connecting portion, a first cutting step of cutting the connecting portion of the silicon wafer, and a cutting of the connecting portion An electrode part forming step of forming an electrode part electrically connected to a strain cage formed on the diaphragm from a surface, and a second step of cutting the glass substrate from a cut portion of the connection part to obtain individual sensor chips. A cutting step, and the grooves formed in the cut surface of the glass substrate and the through holes formed in the circuit board are arranged so as to face each other,
A solder bonding step of connecting a connection land formed on a circuit board and the electrode portion by soldering, a portion around a connection portion between the circuit board and the electrode portion by the solder, and a contact portion between the circuit board and the sensor chip And a step of applying a reinforcing adhesive member to the periphery.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a semiconductor pressure sensor for detecting the pressure of a medium such as a gas or a liquid, and more particularly to a glass pedestal 4 and a diaphragm disposed on the glass pedestal 4 for detecting the pressure of the medium. 1, a pressure introducing hole 13 formed in a surface of the glass pedestal 4 facing the diaphragm 1, and a pressure introducing portion 15 (through hole) facing the pressure introducing hole 13. And an electrode portion 12 formed on the sensor element 2 for connecting the input / output of the sensor element 2 to the circuit board 7. And the connection land 14 are connected by soldering, and the glass pedestal 4 and the cell pedestal 4 are mounted on the circuit board 7 by means such as reflow soldering similarly to other surface mount components mounted on the circuit board 7. Since it is possible to electrically dispose the sensor chip 5 composed of the semiconductor element 2 and the semiconductor element 2, it is possible to obtain a structure capable of improving the productivity as compared with a conventional wire bonding type semiconductor pressure sensor. Can be.

When the conventional semiconductor type pressure sensor in which only the glass pedestal 4 is disposed on the circuit board 7 is of a horizontal mounting type, the semiconductor type pressure sensor of the present invention uses a bridge circuit of the sensor element 2 and a stem. The electrode portion 12 extending to the outer peripheral portion of the glass base 4 and the outer peripheral portion of the glass pedestal 4 are of a vertical mounting type arranged on the circuit board 7, and the mounting area of the circuit board 7 is reduced by using the vertical mounting type. The size of the semiconductor pressure sensor can be reduced because the size of the semiconductor pressure sensor can be reduced as compared with that of a conventional mounting type semiconductor pressure sensor.

The present invention also relates to a method of manufacturing a semiconductor type pressure sensor for detecting the pressure of a medium such as a gas or a liquid, a groove forming step of forming a plurality of grooves 19 of a predetermined shape on the surface of a glass substrate 18, and a groove forming step. 19, the diaphragm 1 of the silicon substrate (silicon wafer) 20 is
The silicon substrate 20 is placed on the glass substrate 1
8; a first cutting step of cutting the connecting portion 21 of each diaphragm 1 of the silicon substrate 20 to form a cutout portion 22; and a cut surface of the connecting portion 21 (cutout portion 22). Forming an electrode portion 12 that is electrically connected to a bridge circuit (strain cage) formed in each diaphragm 1 through a contact hole from a notch portion 22 (a cut portion of the connecting portion 21). Substrate 18
And a second cutting step of forming individual sensor chips 5, a groove (pressure introducing hole 13) 19 formed on the cut surface of the glass substrate 18, and a pressure introducing portion 15 formed on the circuit board 7. A solder bonding step of connecting the connection lands 14 and the electrode portions 12 which are opposed to each other and formed on the circuit board 7 by soldering, a portion where the circuit board 7 and the electrode portions 12 are connected by the solder, and a circuit board 7 and a sensor And a step of applying a reinforcing adhesive (reinforcing adhesive member) 17 around the contact portion with the chip 5.
As with other surface-mounted components mounted on a circuit board, it can be disposed on the circuit board 7 by means such as reflow soldering. Can be improved. In addition, as compared with the conventional semiconductor pressure sensor having the pressure introducing hole 3 penetrating from the front surface to the rear surface of the glass pedestal 4, the pressure introducing hole 1 is formed by forming the groove 19 on the surface of the glass substrate 18.
In the manufacturing process, the glass pedestal 4
Processing cost can be reduced, and the manufacturing cost can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the embodiments shown in the accompanying drawings, but the same or corresponding parts as those in the conventional example will be denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a sectional view of a principal part showing a semiconductor pressure sensor of the present invention, and FIG. 2 is a view showing a method of manufacturing the semiconductor pressure sensor of the present invention.

In FIG. 1, a thin diaphragm 1 is formed in a sensor element 2 integrally with a stem 11 made of a silicon single crystal, and a semiconductor strain gauge (not shown) is provided at a predetermined portion of the diaphragm 1 from a low resistance. It is formed by diffusion so as to form a bridge circuit via a diffusion layer (lead portion). The diffusion layer is electrically connected via a contact hole (not shown) to a surface of the stem 11 opposite to the circuit board 7 which will be described in detail later, and a pressure signal (voltage corresponding to pressure) of the bridge circuit is provided. And an electrode portion 12 made of copper, gold, or the like for inputting and outputting a power signal to and from the bridge circuit is formed by means such as vapor deposition or sputtering.

The glass pedestal 4 is a stem 1 of the sensor element 2.
The diaphragm 1 reaches the contact surface between the glass pedestal 4 and the circuit board 7 from a predetermined position on the opposing surface of the glass pedestal 4 and the sensor element 2.
Further, a groove-shaped pressure introducing hole 13 having a depth of about 10 to 50 μm for transmitting the pressure of the medium is formed.
The sensor element 2 and the glass pedestal 4 constitute a sensor chip 5.

The circuit board 7 is made of an insulating material such as ceramic, has a predetermined wiring pattern (not shown), and includes an amplifier for amplifying a pressure signal output from the sensor chip 5, a capacitor for absorbing external noise, and the like. An electronic component (not shown) is mounted on a land (not shown). The circuit board 7 has connection lands 1 for electrically connecting the electrode portions 12 of the sensor chip 5.
4, a pressure introducing portion (through hole) 15 penetrating from the front surface to the rear surface of the circuit board 7, communicating with the pressure introducing hole 13 of the sensor chip 5, and guiding the pressure of the medium to the sensor chip 5. I have.

The sensor chip 5 having such a configuration is mounted on the circuit board 7.
In this case, cream solder is applied to the connection lands 14 of the circuit board 7, the electrode portions 12 of the sensor chip 5 correspond to the connection lands 14, and the pressure introduction holes 13 of the glass pedestal 4 are connected to the circuit boards 7. The sensor chip 5 is disposed on the circuit board 7 so that the pressure introducing portion 15 of the sensor 7 faces the circuit board 7, and the members 5 and 7 are electrically connected by reflow soldering. Regarding the soldering of the connection land 14 and the electrode portion 12,
The solder application amount is controlled so that the solder fillet 16 is formed between the connection land 14 and the electrode portion 12 in order to improve the bonding strength between the two members 5 and 7.

After the reflow soldering, the circuit board 7
In order to secure airtightness in pressure transmission between the pressure introducing portion 15 and the pressure introducing hole 13 of the glass pedestal 4 and to improve the bonding strength between the members 5 and 7, the circuit around the soldering location and the glass pedestal 4 A semiconductor-type pressure sensor is obtained by applying a predetermined amount of a silicon-based reinforcing adhesive (reinforcing adhesive member) 17 around a contact portion with the substrate 7.

Next, a method of manufacturing such a semiconductor pressure sensor will be described with reference to FIG.

First, a glass substrate 18 made of Pyrex or the like is used.
In order to form a groove 19 serving as the above-described pressure introducing portion 13 having a depth of about 10 to 50 μm and a length of about 3 to 4 mm, for example, a resist film is formed on a portion of the glass substrate 18 excluding the portion where the groove 19 is formed. The groove 1 is formed in the glass substrate 8 by an etching process using a hydrofluoric acid mixed solution, a sand blast method, or the like.
9 are formed at a plurality of locations.
(A). "

Next, a plurality of thin diaphragms 1 are formed on the silicon substrate (silicon wafer) 20, which is a semiconductor substrate, by an appropriate method such as wet etching using an alkaline etching solution such as KOH while leaving the stem 11,
Thereafter, the silicon substrate 20 is put into a thermal oxidation furnace, and a thermal oxide film is formed on the front and back surfaces. The interval between the diaphragms 1 is set so that one end of each of the diaphragms 1 faces the groove 19 formed in the groove forming step with the connecting portion 21 connecting the diaphragms 1 interposed therebetween.

In the diaphragm 1, the thermal oxide film on the surface corresponding to the location where the strain gauge is formed is removed, and the strain gauge is placed at a predetermined position in the diaphragm 1 by diffusion using a semiconductor material such as boron. Is formed, and a thermal oxide film is formed again on the portion where each of the strain gauges is formed.
And, in order to make each said strain gauge into a bridge circuit shape,
For example, the bridge circuit is formed by removing the thermal oxide film from both ends of the strain gauge in a pattern of a predetermined shape, using a semiconductor material such as boron having a higher concentration than the strain gauges, and forming each connection portion by diffusion. Form. After the bridge circuit is formed, a nitride film made of silicon nitride is formed on the thermal oxide film on the surface of the silicon substrate 20.

Next, the nitride film corresponding to the position where each of the junctions is formed is removed by a plasma etching method or the like, and the portion of the thermal oxide film from which the nitride film has been removed is formed using a hydrofluoric acid mixed solution or the like. A “sensor element forming step” in which the sensor element 2 in which each contact hole is formed from the nitride film through the thermal oxide film to reach each of the junctions by removal is formed. The gauge resistance and the joint, the thermal oxide film, the nitride film, and the contact hole in the sensor element forming step are not shown.

Then, a silicon substrate 20 is provided on the glass substrate 18. In this case, one end of each of the diaphragms 1 is disposed so as to face the groove 19 formed in the glass substrate 18 with the connecting portion 21 connecting the respective diaphragms 1 interposed therebetween, and the two members 18 and 20 are anodically bonded. "The joining process,
FIG. 2 (b).

Next, a notch (about 0.2 to 0.3 mm) having a width of about 0.2 to 0.3 mm reaches the glass substrate 18 from the upper end substantially at the center of each connecting portion 21 connecting the diaphragms 1 of the silicon substrate 20. By forming a cutout portion, the stem 11 of the sensor element 2 is formed) 22 is formed by means such as a dicer or the like, and “first cutting step to (c)”. Is disposed, and using a conductive member made of copper, gold, or the like, by vapor deposition, sputtering, or the like,
An electrode part forming step of forming an electrode part 12 extending from the joint part of each diaphragm 1 to the cutout part (cut surface) 21 through the contact hole, as shown in FIG. 2D.

Next, a dicer or the like having a blade having a width smaller than the width of the notch 21 is used to move the bottom of the glass substrate 20 from the upper surface of the glass substrate 20 serving as the bottom of the notch 21 where the electrode 12 is formed. The glass substrate 20 is cut so as to reach the upper limit, and both ends of each of the diaphragms 1 are similarly cut by means such as a dicer.
A sensor chip 5 having a pressure introduction hole 13 in which the pressure of the medium reaches the diaphragm 1 from the cut surface of the glass pedestal 4 is obtained (“second cutting step, FIG. 2E”).

Then, cream solder or the like is applied to the connection lands 14 formed on the circuit board 7 by means such as screen printing, and the electrode portions 12 of the sensor chip 5 are connected to the connection lands 1.
4 and a pressure introducing portion 1 formed on a circuit board 7
The sensor chip 5 is disposed on the circuit board 7 by an automatic mounting machine or the like using an image processing technique so that the pressure introduction hole 13 of the sensor chip 5 and the pressure introduction hole 13 of the sensor chip 5 are opposed to each other, and thereafter, the sensor chip 5 is put into a reflow furnace. The "solder joining step, FIG. 2 (f)" in which the two members 5, 7 are electrically joined.

After the two members 5 and 7 are joined by soldering, a reinforcing adhesive 17 is applied so as to cover the soldering location and the periphery of the contact surface between the circuit board 7 and the sensor chip 5, so that the semiconductor type pressure sensor can be used. The completed “reinforcement adhesive member application step, FIG. 2 (f)”.

As described above, such a semiconductor type pressure sensor electrically connects the sensor chip 5 on the circuit board 7 by means such as reflow soldering similarly to other surface mount components mounted on the circuit board 7. Therefore, it is possible to obtain a structure capable of improving productivity as compared with a conventional wire bonding type semiconductor pressure sensor.

Further, as compared with the conventional semiconductor type pressure sensor having the pressure introducing hole 3 penetrating from the front surface to the rear surface of the glass pedestal 4, the groove 19 as described above is formed on the surface of the glass substrate 18.
Since the pressure introduction hole 13 is obtained by forming
In the manufacturing process, the processing cost of the glass pedestal 4 can be reduced, and the manufacturing cost can be reduced.

When the conventional semiconductor pressure sensor in which only the glass pedestal 4 is disposed on the circuit board 7 is of a horizontal mounting type, the semiconductor pressure sensor of the present invention has the bridge circuit ( The electrode portion 12 extending from the strain gauge to the outer peripheral portion of the stem 11 through the contact hole and the outer peripheral portion of the glass pedestal 4 are of a vertical mounting type provided on the circuit board 7, and are of a vertical mounting type. As a result, the mounting area of the circuit board 7 can be reduced as compared with a conventional semiconductor pressure sensor of a horizontal mounting type, so that the semiconductor pressure sensor can be downsized.

In the semiconductor pressure sensor according to the present invention, the pressure introducing hole 13 is formed on the surface of the glass pedestal 4 facing the sensor element 2. Alternatively, a pressure introduction hole may be formed so as to communicate from a predetermined position on the bonding surface of the glass pedestal 4 with the circuit board 7 to a predetermined position on the facing surface.

[0034]

According to the present invention, there is provided a semiconductor pressure sensor for detecting the pressure of a medium such as a gas or a liquid.
A sensor element disposed on the glass pedestal and forming a diaphragm for detecting the pressure of the medium, a circuit board on which a wiring pattern and a connection land are formed at a predetermined location, and input and output of the sensor element An electrode portion formed on the sensor element for connection to a circuit board, wherein the electrode portion and the connection land are connected by soldering; In the semiconductor type pressure sensor for detecting, a glass pedestal, a sensor element disposed on the glass pedestal and forming a diaphragm for detecting the pressure of the medium, and formed on an opposing surface of the glass pedestal facing the diaphragm. A pressure-introducing hole, a circuit board in which a through-hole opposed to the pressure-introducing hole is formed, and a predetermined wiring pattern and a connection land are formed. In order to connect the input / output of the sensor element to the circuit board, an electrode section formed on the sensor element is formed, and the electrode section and the connection land are connected by soldering. It is possible to electrically dispose a sensor chip composed of the glass pedestal and the sensor element on the circuit board by means such as reflow soldering as in the case of other surface mount components mounted on the circuit board. Therefore, it is possible to obtain a structure that improves productivity as compared with a conventional wire bonding type semiconductor pressure sensor.

When the conventional semiconductor pressure sensor in which only the glass pedestal is disposed on the circuit board is of a horizontal mounting type, the semiconductor pressure sensor of the present invention extends to the outer peripheral portion of the sensor element. The formed electrode portion and the outer peripheral portion of the glass pedestal are of a vertical mounting type disposed on the circuit board, and the vertical mounting type reduces the surface mounting area of the circuit board to the horizontal mounting type. Since the size of the semiconductor pressure sensor can be reduced as compared with the conventional semiconductor pressure sensor, the size of the semiconductor pressure sensor can be reduced.

The present invention also relates to a method of manufacturing a semiconductor pressure sensor for detecting the pressure of a medium such as a gas or a liquid.
A groove forming step of forming a plurality of grooves of a predetermined shape on the surface of the glass substrate, and bonding the silicon wafer to the glass substrate so that two or more diaphragms of the silicon wafer face the grooves via a connecting portion. Step, a first cutting step of cutting the connection portion of the silicon wafer, and an electrode portion forming step of forming an electrode portion electrically connected to a strain cage formed in the diaphragm from a cut surface of the connection portion And a second cutting step of cutting the glass substrate from a cut portion of the connection portion to obtain individual sensor chips; and a groove formed in a cut surface of the glass substrate and a through hole formed in a circuit board. Are disposed so as to face each other, and a solder bonding step of connecting the connection land formed on the circuit board and the electrode section by soldering, and a step of connecting the circuit board and the electrode section to each other. A step of applying a reinforcing adhesive member around the connection point by the solder and around the contact point between the circuit board and the sensor chip, and other surface mounting to be mounted on the circuit board. Since a sensor chip composed of the glass pedestal and the sensor element can be disposed on the circuit board by means of reflow soldering or the like in the same manner as a component, a conventional semiconductor bonding pressure of a wire bonding method is used. The productivity can be improved as compared with the sensor. In addition, compared to a conventional semiconductor pressure sensor having a pressure introducing hole penetrating from the front surface to the rear surface of the glass pedestal, the pressure introducing hole can be obtained by forming the groove on the surface of the glass substrate. In the process, the processing cost of the glass pedestal can be reduced, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a semiconductor type pressure sensor of the present invention.

FIG. 2 is a view showing a method of manufacturing the semiconductor pressure sensor according to the first embodiment;

FIG. 3 is a sectional view of a main part showing a conventional semiconductor pressure sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diaphragm 2 Sensor element 4 Glass pedestal 5 Sensor chip 7 Circuit board 11 Stem 12 Electrode part 13 Pressure introduction hole 14 Connection land 15 Pressure introduction part (through hole) 17 Reinforcement adhesive (reinforcement adhesive member) 18 Glass substrate 19 Groove part 20 Silicon substrate (silicon wafer) 21 Connecting part 22 Notch

Claims (4)

[Claims] 1. A semiconductor pressure sensor for detecting a pressure of a medium such as a gas or a liquid, wherein the sensor element includes a glass pedestal and a diaphragm disposed on the glass pedestal for detecting the pressure of the medium. A circuit board on which a wiring pattern and a connection land are formed at a predetermined location, and an electrode section formed on the sensor element for connecting input and output of the sensor element to the circuit board. A semiconductor pressure sensor, wherein the connection land is connected by soldering. 2. A semiconductor pressure sensor for detecting a pressure of a medium such as a gas or a liquid, comprising: a glass pedestal; a sensor element disposed on the glass pedestal and forming a diaphragm for detecting a pressure of the medium; A pressure introducing hole formed on a surface of the glass pedestal facing the diaphragm, a circuit board forming a through hole facing the pressure introducing hole, and a predetermined wiring pattern and a connection land formed thereon, and the sensor And an electrode part formed on the sensor element for connecting input / output of the element to the circuit board. The semiconductor type wherein the electrode part and the connection land are connected by soldering. Pressure sensor. 3. The semiconductor type according to claim 1, wherein a reinforcing adhesive member is applied around a connection portion by the solder and around a contact portion between the circuit board and the glass pedestal. Pressure sensor. 4. A method of manufacturing a semiconductor pressure sensor for detecting a pressure of a medium such as a gas or a liquid, wherein a groove forming step of forming a plurality of grooves having a predetermined shape on a surface of a glass substrate; A bonding step of bonding the silicon wafer on the glass substrate such that two or more diaphragms face each other via a connecting portion, a first cutting step of cutting the connecting portion of the silicon wafer, and a cutting of the connecting portion An electrode portion forming step of forming an electrode portion electrically connected to a strain cage formed in the diaphragm from a surface,
A second cutting step of cutting the glass substrate from the cut portion of the connection portion to obtain individual sensor chips, wherein the groove formed in the cut surface of the glass substrate and the through hole formed in the circuit board face each other. And a soldering step of connecting the connection land formed on the circuit board and the electrode portion by soldering, and a step of connecting the circuit board and the electrode portion with each other by the solder and the circuit board. And a step of applying a reinforcing adhesive member around a contact point of the sensor chip and the sensor chip.