JPH07218365A - Semiconductor pressure sensor and manufacture thereof - Google Patents

Abstract

PURPOSE:To raise yield of a pressure sensor and to prevent a decrease in sensitivity of the sensor. CONSTITUTION:A recess 4 is formed in a frame 1, and a wiring part 6 and a pad 5 spatially connected to the recess 4 are recessed. A movable electrode lead pad 9 connected to a movable electrode 8 and a stationary electrode lead pad 10 are formed at the pad 5. A lead wiring 14 and a contact bonding pad 13 are formed at the part 6. A stationary electrode 8 and a wiring 15 connected to the electrode 8 are formed on an inner surface of a cover 2, and a periphery of the cover 2 is connected to the frame 1 by an anode connecting method, etc. In this case, the wiring 14 is press-bonded to the pad 13, and the stationary electrode 8 is electrically connected to the pad 10. Two lead holes 15 are so formed at the cover 2 at positions as not to be engaged with an end of the cover 2, and bonding wires connected to both the pads 9, 10 are extended from the holes 15, 15. A reference pressure is introduced from the holes 15 into the recess 4.

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 and its manufacturing method. Specifically, the present invention relates to an electrode lead-out structure of a capacitance type semiconductor pressure sensor and a method of manufacturing the semiconductor pressure sensor.

[0002]

2. Description of the Related Art FIGS. 6A and 6B are a plan view and a sectional view, respectively, showing a conventional electrostatic capacitance detection type semiconductor pressure sensor E. The pressure sensor E is a thin film diaphragm 5
A recess 54 is formed in a frame 52 in which the diaphragm 1 is disposed substantially in the center thereof so that the diaphragm 51 can be swingably displaced in its thickness direction, and a cover 53 is joined to the upper surface thereof. A movable electrode 55 is formed on the upper surface of the diaphragm 51, and the movable electrode 55 is electrically connected to a bonding pad 62 on the upper surface of the frame 52. Further, a fixed electrode 56 is formed on the inner surface of the cover 53 with a small gap from the movable electrode 55, and the fixed electrode 56 is taken out by crimping a connection wiring 57 and a crimping pad 58 provided on the inner surface of the cover 53. It is electrically connected to the wiring 59 and is electrically connected to another bonding pad 60 provided on the exposed portion of the frame 52.

[0003]

However, in the pressure sensor E having such a structure, the take-out wiring 5 is used.
9 is the recess 52 from the recess 54 on the upper surface of the frame 52.
The insulating film 63 is disposed in a groove-shaped take-out portion 61 that is recessed toward the side end portion of the sheet, and a gap 64 is formed between the frame 52 and the cover 53 in the take-out portion 61. For this reason, the cooling water used in the dicing process when the pressure sensor is manufactured is depressed from the gap 64 to the recess 5
There is a possibility that the movable electrode 55 and the fixed electrode 56 may be fixed to each other by infiltrating into the inside of No. 4, and as a result, the yield of the pressure sensor E may be reduced.

Further, the dust particles generated by the dicing together with the cooling water enter the depression 54, and the diaphragm 5
No. 1 displacement was hindered, causing deterioration of sensor characteristics.

Although not shown, the extraction wiring 61 is formed by introducing impurities into the frame 52 without forming the extraction portion 61 in a recess.
Forming a bonding pad 60 on the upper surface of the frame 52.
Although it may be possible to electrically connect to the pressure sensor, such a configuration has a problem that the manufacturing method of the pressure sensor becomes complicated. Moreover, when the extraction wiring 59 is formed by forming a conductive layer, the surface of the extraction wiring 59 slightly rises. Therefore, the extraction wiring 59
A minute step was formed at the boundary between the frame 52 and the frame 52, and the gap between the frame 52 and the cover 53 could not be completely eliminated.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to prevent the entry of cooling water or dust to improve the yield of the pressure sensor and to deteriorate the sensor characteristics. Is to prevent the pressure sensor from being produced and to simplify the manufacturing process of the pressure sensor.

[0007]

According to the capacitance type pressure sensor of the present invention, a pressure chamber is formed between two bonded substrates, and a change in capacitance between electrodes provided on the inner surface of the pressure chamber. As a capacitance type sensor for detecting pressure, a hole portion that serves as a hole for introducing pressure to the pressure chamber and a hole for drawing out a lead wire electrically connected to the electrode, It is characterized in that it is provided at a position where it does not reach the end portion of either one of the substrates. One hole may be provided and two lead wires may be drawn out from this hole.

Further, it is desirable to join the outer peripheral region of the substrate in an annular shape.

Further, a recess spatially connected to the pressure chamber is provided in the remaining substrate having no hole, and a pair of extraction pads electrically connected to the electrodes are provided in the recess. It may be provided so as to correspond to the position of the hole. At this time, the electrode provided on the inner surface of the substrate having the hole is provided with the connection wiring electrically connected to the electrode on the inner surface of the substrate, and the connection wiring and the extraction pad provided on the remaining substrate. It is also possible to electrically connect to the extraction pad by crimping with a connection wiring electrically connected to.

Further, the extraction pad and the connection pad may be connected by the extraction wiring. further,
The connection pad may be annularly provided on the outer peripheral portion of the hole.

Further, it is desirable that the connection pad is provided in a recess provided in the substrate so that the surface of the connection pad is lower than the surface of the substrate provided with the connection pad.

A method of manufacturing an electrostatic capacity type pressure sensor of the present invention is a method for manufacturing a large number of the electrostatic capacity type pressure sensors described above, in which two parent substrates are bonded together to form a large number of pressure sensor chips. Is formed, and a sheet material is adhered to the parent substrate provided with the hole to close the hole, and the two joined parent substrates are cut to manufacture the pressure sensor.

[0013]

In the capacitance type pressure sensor of the present invention, since the hole portion also serving as the hole for drawing out the takeout wiring is provided at a position where it does not reach the end portion of the substrate, it is provided in the inner peripheral area of the substrate bonding surface. A pad or the like for connecting the extraction wiring can be provided. Therefore, unlike the conventional pressure sensor, a gap is not formed in the joint surface of the substrate due to the extraction wiring, and the pressure sensor can be manufactured without a complicated manufacturing process.

For example, even when a large number of pressure sensors are manufactured by cutting a parent substrate on which a large number of pressure sensor chips are formed with a dicing saw or the like, cooling water or the like does not enter from the joint surface of the substrates. Therefore, adhesion between the electrodes due to cooling water is prevented, and displacement of the diaphragm is not hindered. Therefore, it is possible to improve the yield of the pressure sensor and prevent the sensor sensitivity from decreasing. Even in this case, since the hole is provided at a position that does not cover the edge of the substrate, if the sheet is bonded and cut with a sheet material such as dicing tape so as to close the hole, cooling water will be removed from the hole. It goes without saying that foreign matter such as shavings and shavings can be prevented from entering the pressure chamber.

Further, since the hole portion also serves as a hole for introducing pressure into the pressure chamber, it is not necessary to separately form a hole for introducing pressure, and one hole portion is formed as one hole portion. By pulling out two lead wires from the above, the structure and manufacturing process of the pressure sensor can be further simplified.

For this purpose, if the peripheral portion is joined in an annular shape, cooling water and the like will not enter the pressure chamber between the two substrates.

If a take-out pad electrically connected to the electrode corresponding to the position of the hole is provided in the recess provided in the substrate having no hole, the take-out pad is taken out to this take-out pad. By connecting the wiring, it is possible to easily pull out the extraction wiring.

Further, since the connection pad is provided on the substrate having the hole and the extraction wiring connected to the electrode is connected to the connection pad (of course, the extraction wiring may be connected to the extraction pad). The take-out wiring can be easily connected to the detection circuit or the like, and the take-out wiring is less likely to be cut by the edge of the hole or the like. If the connection pad is provided in an annular shape on the outer peripheral portion of the hole, it is possible to easily connect the extraction wiring.

Further, since the connection pad is provided in the recess provided in the substrate so that the surface of the connection pad is lower than the surface of the substrate provided with the connection pad, the sheet material is adhered so as to close the hole. However, the adhesive or the like does not adhere to the connection pad, and the connection of the take-out wiring or the like can be reliably performed.

In the manufacturing method of the present invention, since the sheet material is adhered to the parent substrate on which a large number of pressure sensor chips are formed to close the holes and then cut, cooling water or the like is discharged from the holes or the like. It is possible to form a large number of pressure sensors at the same time with high yield without invading.

[0021]

1 (a) and 1 (b) are a plan view and a sectional view, respectively, showing a capacitance type pressure sensor A according to an embodiment of the present invention. In the pressure sensor A, a diaphragm 3 is arranged substantially in the center of a frame 1 having a rectangular frame shape, and a recess 4 is formed on the upper surface of the frame 1 so that the diaphragm 3 can be freely displaced in its thickness direction. There is. Further, a pad portion 5 is provided on the outer end portion of the frame 1 so as not to reach the end portion of the frame 1, and the recess 4 and the pad portion 5 are spatially formed by a groove-shaped wiring portion 6 provided on the frame 1. It is connected to the. The frame 1 and the diaphragm 3 are integrally formed from a silicon substrate (wafer) by anisotropic etching or the like, and the recess 4, the pad portion 5, and the wiring portion 6 are also formed by etching or the like. Impurities are diffused on the upper surface of the diaphragm 3 so that the diaphragm 3 has conductivity and has a movable electrode 7.
And is electrically connected to the movable electrode extraction pad 9 provided on the pad portion 5. A cover 2 made of glass is stacked on the upper surface of the frame 1, and the periphery of the recess 4, the pad portion 5, and the wiring portion 6 are joined by an anodic bonding method or the like. An insulating film 11 made of SiO ₂ is provided on the upper surface of the frame 1 from the wiring portion 6 to the pad portion 5, and extraction wiring 12 for pulling out the fixed electrode 8 is arranged on the insulating film 11 and the pad portion 5 is provided. Is connected to the fixed electrode extraction pad 10 provided on the. Further take-out wiring 12
The pressure bonding pad 13 is formed on the pressure bonding pad 13
And the lead-out wiring 12 and the fixed electrode lead-out pad 10 are made of Al.
The metal thin film deposited by, for example, is patterned and integrally formed.

On the inner surface of the cover 2, a fixed electrode 8 made of a metal thin film and a connection wiring 14 are integrally provided.
By connecting the frame 1 and the cover 2, the connection wiring 14 is pressure-bonded to the pressure-bonding pad 13 to be electrically connected, and the fixed electrode 8 is electrically connected to the fixed-electrode extraction pad 10. In addition, the cover 2 has extraction holes 1 corresponding to the positions of the movable electrode extraction pad 9 and the fixed electrode extraction pad 10.
Two holes 5 and 15 are formed at positions where they do not reach the ends of the cover 2, and bonding wires (not shown) connected to the pads 9 and 10 can be taken out from the holes.

Next, a method of manufacturing the pressure sensor A will be briefly described. Dry etching is performed on one sensor of the silicon wafer to be the frame 1 to integrally form the depression 4, the wiring portion 6 and the pad portion 5. Next, the wiring section 6
After forming an insulating film 11 by forming an oxide film on the pad portion 5, the metal thin film on which Al or the like is deposited is patterned to form the fixed electrode extraction pad 10, the extraction wiring 12 and the pressure bonding pad 13. Separately from this, the metal thin film is patterned to form the movable electrode extraction pad 9. Next, the silicon wafer is etched with a potassium hydroxide aqueous solution to form the diaphragm 3, and the frame 1
A silicon wafer having a large number of formed is prepared.

A take-out hole 15 is formed in the glass substrate which becomes the cover 2.
To open. A metal thin film formed by vapor deposition of Al or the like is patterned on the back surface of the glass substrate to form the fixed electrodes 8 and the connection wirings 14 to form a glass substrate having a large number of covers 2. After bonding the silicon wafer thus produced and the glass substrate, a sheet material 16 such as a dicing tape is adhered to the glass substrate so as to close the extraction hole 15 as shown in FIG. A large number of pressure sensors A having the same structure can be simultaneously manufactured by dicing cutting between the sensors with a blade 17.

Thus, the pressure sensor A having such a structure
In this case, when the measurement pressure is introduced under the diaphragm 3, the diaphragm 3 is displaced in the thickness direction according to the pressure difference from the reference pressure in the depression 4, and the fixed electrode 8 and the fixed electrode 8 are displaced according to the displacement. The capacitance with the movable electrode 7 changes. The introduced measurement pressure can be known by detecting the change in the electrostatic capacity by a detection circuit or the like connected to the bonding wire. Further, since the extraction hole 15 is spatially connected to the recess 4 through the pad portion 5 and the wiring portion 6, it is possible to introduce the reference pressure into the depression 4 from the extraction hole 15, and to introduce the reference pressure. Since it is not necessary to separately open the mouth, the manufacturing process of the pressure sensor A can be simplified.

When the pressure sensor A is manufactured in this manner, the movable electrode take-out pad 9 and the fixed electrode take-out pad 10 are provided in the pad portion 5, and the frame 1 and the cover 2 are joined to each other in an annular shape in the outer peripheral area thereof. Therefore, there is no gap around the depression 4 and the pad portion 5. Further, since a sheet material such as a dicing tape is adhered so as to close the take-out hole 15 and then the dicing is performed, the frame 1
Cooling water, dust and the like do not enter the recess 4 between the cover 2 and the cover 2 or through the extraction hole 15. Therefore, the pressure sensor A can be manufactured with high yield, and the sensitivity of the sensor does not decrease.

Further, FIG. 3 shows another pressure sensor B of the present invention, which is located in the pad portion 5 and is the takeout hole 1
It is also possible to open one hole 5 and take out the two bonding wires from the single taken-out hole 15. In this way, by opening one extraction hole 15, the structure and manufacturing process can be further simplified.

FIGS. 4A and 4B are a plan view and a sectional view showing a pressure sensor C which is still another embodiment of the present invention. Connection pads 21 and 22 are provided around the take-out hole 15 on the upper surface of the cover 2, respectively. The fixed electrode extraction pad 10 of the pad portion 5 is once connected to the connection pad 21 by the bonding wire 23, and is further electrically connected from the connection pad 21 to the detection circuit or the like by another bonding wire. Similarly, the movable electrode extraction pad 9 of the pad portion 5 is also once connected to the connection pad 22 by the bonding wire 23 and further connected to the detection circuit and the like. In the pressure sensor A of the first embodiment, when the fixed electrode lead-out pad 10 (movable electrode lead-out pad 9) of the pad portion 5 is directly connected to a detection circuit or the like on the mounting board by a bonding wire,
The cover 2 and the bonding wire may come into contact with each other at the opening of the extraction hole 15 to cause disconnection or contact failure. However, in the pressure sensor C, since the pressure sensor C is once connected to the connection pads 21 and 22 and then connected to the detection circuit or the like, the bonding wire 23 is provided with a margin so as not to come into contact with the opening of the takeout hole 15. It is possible to eliminate such inconvenience.

Further, FIGS. 5A and 5B are a plan view and a sectional view showing a pressure sensor D which is still another embodiment. The connection pads 21 and 22 are provided in an annular shape in the outer peripheral area of the extraction hole 15 in the recess 24 formed in the cover 2. In this way, the connection pads 21 and
2 is formed, the connection pads 21 and 2 are previously formed.
Even when dicing is cut after the provision of 2, the sheet material 16 does not come into contact with the connection pads 21 and 22. Therefore, the surfaces of the connection pads 21 and 22 do not become dirty,
The bonding wire 23 can be surely connected.

[0030]

In the electrostatic capacitance type pressure sensor of the present invention, the hole portion also serving as the hole for drawing out the take-out wiring is provided at a position which does not cover the end portion of the substrate, so that it is provided in the inner peripheral area of the substrate. A pad or the like for connecting the extraction wiring can be provided. Therefore, the pressure sensor can be easily manufactured without forming a gap on the bonding surface of the substrate. Therefore, for example, even when a large number of pressure sensors are simultaneously manufactured by dicing cutting or the like, cooling water and shavings do not enter the pressure chamber through the gaps in the substrate,
It is possible to prevent a decrease in yield and a decrease in sensor sensitivity.

Further, since the hole portion also serving as a hole for introducing into the pressure chamber is provided, it is not necessary to separately provide a pressure introducing port, and one hole portion is provided, and two lead wires are taken out from this hole portion. By pulling out, the structure of the pressure sensor and the manufacturing process can be further simplified.

Further, since a recess is provided in the substrate in which the hole is not provided and an extraction pad connected to the electrode is provided in the recess corresponding to the position of the hole, the extraction wiring is connected to the extraction pad. The wiring can be easily pulled out from the hole. Of course, the extraction pads and the connection pads on the substrate provided with the holes may be connected by extraction wiring. By doing so, the connection with the detection circuit is facilitated, and the disconnection and contact failure of the take-out wiring are reduced.

Further, since the connection pad is provided in the recess provided in the substrate so that the surface of the connection pad is lower than the surface of the substrate, an adhesive agent such as a sheet material for closing the hole is connected. It does not adhere to the pad, and it is possible to reliably connect the extraction wiring.

According to the manufacturing method of the present invention, since the holes are closed and then cut, cooling water or the like does not enter the pressure chamber, and a large number of pressure sensors can be easily manufactured with high yield.

[Brief description of drawings]

1A and 1B are a plan view and a cross-sectional view, respectively, showing a capacitance type pressure sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a step in the method of manufacturing the capacitance pressure sensor of the same.

3 (a) and 3 (b) are respectively a plan view and a cross-sectional view showing a capacitance type pressure sensor which is another embodiment of the present invention.

4A and 4B are a plan view and a sectional view, respectively, showing a capacitance type pressure sensor which is still another embodiment of the present invention.

5A and 5B are a plan view and a sectional view, respectively, showing a capacitance type pressure sensor which is still another embodiment of the present invention.

6A and 6B are respectively a plan view and a cross-sectional view showing a capacitance type pressure sensor which is a conventional example.

[Explanation of symbols]

 2 cover 4 dent 8 fixed electrode 10 fixed electrode take-out pad 15 take-out hole also serving as pressure inlet 16 sheet material 21 connection pad 23 bonding wire

Claims (10)

[Claims] 1. A capacitance type sensor which forms a pressure chamber between two bonded substrates and detects pressure as a change in capacitance between electrodes provided on the inner surface of the pressure chamber, wherein the pressure chamber A hole portion that doubles as a hole for introducing pressure to the electrode and a hole for pulling out the extraction wiring electrically connected to the electrode is provided at a position that does not extend to the end of one of the substrates. Capacitive pressure sensor. 2. The capacitance type pressure sensor according to claim 1, wherein one hole is provided and two lead wires are drawn out from the hole. 3. The capacitance type pressure sensor according to claim 1, wherein the outer peripheral region of the substrate is joined in an annular shape. 4. A recess that is spatially connected to the pressure chamber is provided in the remaining substrate where the hole is not provided, and a pair of extraction pads electrically connected to the both electrodes is provided in the recess. The capacitance type pressure sensor according to claim 1, 2 or 3, wherein the capacitance type pressure sensor is provided so as to correspond to the position of the hole. 5. A connection wiring electrically connected to an electrode provided on an inner surface of the substrate provided with the hole is provided on the inner surface of the substrate, and the connection wiring and the extraction pad provided on the remaining substrate are electrically connected to each other. The electrostatic capacitance type pressure sensor according to claim 4, wherein the electrode is electrically connected to the extraction pad by pressure bonding with a connection wiring that is electrically connected. 6. A pair of connection pads are provided on the substrate provided with the holes, and lead wires electrically connected to the electrodes are connected to the connection pads.
Alternatively, the electrostatic capacitance type pressure sensor described in 5. 7. The capacitance type pressure sensor according to claim 6, wherein the extraction pad and the connection pad are connected by the extraction wiring. 8. The capacitance type pressure sensor according to claim 6, wherein the connection pad is provided in an annular shape on the outer peripheral portion of the hole. 9. The connection pad is provided in a recess provided in the substrate such that the surface of the connection pad is lower than the surface of the substrate provided with the connection pad. Capacitive pressure sensor according to. 10. The method according to claim 1, 2, 3, 4, 5, 6, 7,
A method for manufacturing a large number of capacitive pressure sensors according to 8 or 9, wherein a plurality of pressure sensor chips are formed by joining two parent substrates, and the parent substrate having the holes is formed. A method for manufacturing an electrostatic capacitance type pressure sensor, comprising: adhering a sheet material to close the hole, and then cutting the two bonded parent substrates to manufacture individual pressure sensors.