JP2001174349A - Semiconductor pressure sensor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor and its manufacturing method capable of forming a pressure guide hole adaptable to a semiconductor pressure sensor chip smaller in size than a conventional one and capable of miniaturizing the package size of the semiconductor pressure sensor. SOLUTION: A glass substrate with metal wires having one or multiple metal wires 15 exposed with end sections to a first main surface and a second main surface in the direction nearly perpendicular to a main surface is used for a glass pedestal 2 of the semiconductor pressure sensor chip 1.

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 pressure by displacement of a diaphragm and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 9 shows an example of the configuration of a conventional semiconductor pressure sensor. This semiconductor pressure sensor is intended to measure a pressure in a minute pressure region. First, a semiconductor pressure sensor chip unit (hereinafter, referred to as a chip unit) 1 which is a main body of the semiconductor pressure sensor will be described. As shown in FIG. 9, a diaphragm 7 having a thin structure is formed by etching the lower surface of a semiconductor substrate (silicon substrate), and a piezoresistor 6 whose resistance value changes due to displacement of the diaphragm 7 is formed on the diaphragm 7. ing. Next, as a pedestal of the chip 1, a glass pedestal 2 having a pressure introducing hole 5 in a central portion is joined, and a metal package 3 having a pressure introducing hole 5 'is further joined. Here, glass pedestal 2
Pressure introduction hole 5 and pressure introduction hole 5 ′ of metal package 3 are on the same center line, and external pressure is applied to pressure introduction holes 5 and 5 ′.
Through the diaphragm 7. As a result, the diaphragm 7 receives stress, and the piezoresistor 6 formed on the diaphragm 7 receives stress, so that its resistance value changes. An electric signal due to the change in the resistance value is output to the outside via the wire 8 and the external connection pin 9.

The chip part 1 is bonded to the glass pedestal 2 by a method such as anodic bonding. The glass pedestal 2 is made of Pyrex glass (for example, Corning Corp. trademark # 7740) and has a metallized surface 19. The metallized surface 19 and the metal package 3 made of Kovar, 42 alloy or the like are connected by solder 4 or the like. The external connection pins 9 are bonded to the electrode portions (not shown) of the chip portion 1 by gold or aluminum wires 8. Further, the external connection pins 9 are fixed to the metal package 3 with borosilicate glass 13 or the like, the surface of the chip portion 1 having the piezoresistor 6 is protected by the overcoat 11, and the chip portion 1 and its peripheral portions are Covered and protected by a cap 10, the cap 10 is connected to the package 3 by a weld 12.

FIG. 10 is a sectional view of a conventional chip portion 1 (before dicing, pressure sensor wafer) and a glass pedestal 2 (before dicing) after anodic bonding. The thickness of the glass pedestal 2 is about 1 to 3 mm, the pressure introducing hole 5 is formed by ultrasonic processing, and the diameter is at least about 0.8 mm. The minimum pitch between the pressure introducing holes 5 is about 2.5 m.
m. The ultrasonic processing is a method in which an ultrasonic wave and a load are applied to a pin on a sword mountain in contact with a glass plate, and a hole (pressure introduction hole 5) is formed in the glass plate in an abrasive.

[0005]

However, the pin-shaped pin is required to have a high strength and to have a maintenance property such as cleaning and adjustment in the pressure introducing hole forming step. Further, in forming the pressure introducing hole 5 in this conventional method, the minimum diameter of the pressure introducing hole 5 is about 0.8 m as described above.
m is the limit, and the pitch between the pressure introducing holes is also a minimum of about 2.5 mm. Therefore, for example, it cannot be applied to a semiconductor pressure sensor chip (chip unit 1) in which one chip size is about 1 mm square and the size of the diaphragm 7 is 0.7 mm × 0.7 mm.

Further, as shown in FIG. 9, since the connection between the chip portion 1 and the external circuit is made by bonding using the external connection pins 9 and the electrode portion of the chip portion 1, the semiconductor pressure is reduced. There was a problem that the package size of the sensor became large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to form a pressure introducing hole which can be applied to a semiconductor pressure sensor chip smaller than a conventional size, and to provide a semiconductor pressure sensor. Another object of the present invention is to provide a semiconductor pressure sensor and a method for manufacturing the same, which can reduce the package size.

[0008]

In order to achieve the above object, according to the present invention, there is provided a diaphragm which is displaced by pressure, a semiconductor pressure sensor chip for detecting pressure by displacement of the diaphragm, and a semiconductor pressure sensor chip. A semiconductor pressure sensor having a glass pedestal having a pressure introducing hole for introducing pressure into the diaphragm with a sensor chip mounted thereon, the semiconductor pressure sensor being substantially perpendicular to the main surface, and having a first main surface and a second main surface. A glass substrate with a metal wire having one or a plurality of metal wires whose ends are exposed is used as the glass pedestal.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor pressure sensor according to the first aspect, a part or all of the metal wires of the glass substrate containing the metal wires are removed, and the metal wire removal part is pressure-introduced. The glass pedestal is formed as a hole, and one or more semiconductor pressure sensor chips are mounted and joined to the main surface of the glass pedestal such that the pressure introduction hole and the diaphragm face each other. It is assumed that.

According to a third aspect of the present invention, in the method for manufacturing a semiconductor pressure sensor according to the second aspect, the metal lines of the glass substrate containing the metal lines are removed by etching.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor pressure sensor according to the third aspect, the material of the metal wire of the glass substrate containing the metal wire is molybdenum, and the metal wire is made of a ferric chloride solution. It is characterized by being removed by etching.

According to a fifth aspect of the present invention, in the method for manufacturing a semiconductor pressure sensor according to the first aspect or the semiconductor pressure sensor according to the second aspect, the metal wire of the glass substrate containing the metal wire is connected to the semiconductor pressure sensor chip. It is characterized in that it is joined to an electrode to form a lead wire.

According to a sixth aspect of the present invention, in the semiconductor pressure sensor according to the fifth aspect, a part or all of the metal wires of the glass substrate with metal wires are removed, and another metal is buried in the removed portion. The metal is joined to the electrode portion of the semiconductor pressure sensor chip to form a lead wire.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a semiconductor pressure sensor according to any one of the first to sixth aspects, wherein one metal wire or a plurality of metal wires is substantially parallel to a predetermined metal wire. Arranged at intervals, the metal wire is put into molten glass, then the molten glass is solidified to form a solid glass containing the metal wire, and then the solid glass is substantially orthogonal to the metal wire. The method is characterized in that a glass substrate containing a metal wire is formed by slicing.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor pressure sensor and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to FIGS.
It will be explained based on the following. In the drawings, the upper portion of the semiconductor substrate (silicon substrate 1) is referred to as an upper surface, and the lower portion is referred to as a lower surface.

FIG. 1 is a sectional view of a semiconductor pressure sensor according to a first embodiment of the present invention, and FIG.
Shown in FIG. 1 shows a semiconductor pressure sensor (chip unit 1) wafer before dicing and a glass pedestal 2 having a fine through hole (pressure introducing hole 5) of about 0.1 to 0.5 mm in a vacuum or atmosphere. Temperature of about 300-400 ° C, 600-10
This shows a state in which anodic bonding is performed by a DC voltage of 00V. The center of the through-hole (pressure introduction hole 5) is joined so as to be located at the center of the diaphragm 7 of the chip portion 1, and external pressure is guided to the diaphragm 7 through the pressure introduction hole 5. As a result, the diaphragm 7 receives stress, and the diaphragm 7
When the piezoresistor 6 formed above receives stress, its resistance value changes. An electric signal due to the change in the resistance value is output to the outside by the electrode portion (electrode pad 14). Here, glass containing a metal wire is used for the glass pedestal 2. The glass with a metal wire is a metal wire 15 having a high melting point of tungsten (melting point 3387 ° C.) and molybdenum (melting point 2610 ° C.)
It is formed integrally with glass containing movable metal ions capable of anodic bonding. In this glass with metal wire,
For example, there is SD2-WIN (trademark) manufactured by HOYA Corporation. In the present invention, the glass with the metal wire is sliced so that the metal wire 15 is substantially perpendicular to the main surface and the ends are exposed on the first main surface and the second main surface. Used as a substrate. FIG. 8 shows an example of this manufacturing method. A glass raw material is put into a heat-resistant container, and at the same time, metal wires 15 'stretched at substantially equal intervals are set (a). After heating and melting at about 1600 ° C., stirring and homogenizing and defoaming, casting into a mold preheated to an appropriate temperature, and after cooling (b), the metal wire is perpendicular to the metal wire 15 ′. It is formed by slicing.

Here, the pressure introducing hole 5 is formed by removing the metal wire 15 of the glass substrate containing the metal wire by etching or the like, and this glass substrate is used as the glass pedestal 2. In the present embodiment, as shown in FIG. 2, a glass substrate with a metal wire is formed or cut in the same shape (circle) as the semiconductor pressure sensor (chip unit 1) wafer (a), and the metal of the glass substrate with a metal wire is formed. The pressure introduction hole 5 is formed by removing the line 15 by etching, and this is used as the glass pedestal 2 (b). For example, when the metal wire 15 is molybdenum, it is immersed in a ferric chloride solution to perform etching. The glass pedestal 2 and the semiconductor pressure sensor (chip unit 1) wafer are anodically bonded so that the position of the pressure introducing hole 5 and the position of the diaphragm 5 of the chip unit 1 coincide. Where, for example,
A section taken along the line AA ′ is as shown in FIG. Then, dicing is performed by a broken line in FIG. 1 to generate one semiconductor pressure sensor.

As described above, the metal wire 15 of the glass substrate containing the metal wire is removed, and the portion where the metal wire 15 is removed is inserted into the pressure introducing hole 5.
The semiconductor pressure sensor chip (chip unit 1) is mounted and joined on the main surface of the glass pedestal 2 so that the pressure introducing hole 5 and the diaphragm 7 face each other. (Approximately 0.1 to 0.5 mm in diameter) It is possible to produce a semiconductor pressure sensor having the pressure introducing hole 5.

FIGS. 3 and 4 show a second embodiment of the present invention.
Shown in FIG. 3 is a sectional view at the time of anodic bonding, and FIG.
FIG. 3 is a main surface view of a piezoresistor 6, an electrode pad 14, a portion between the piezoresistors 6, and an electrode pad 1 formed on the chip portion 1.
Aluminum wiring connecting chip 4 on chip 1 surface, chip 1
And the aluminum pad 16 for bonding (anode) formed so as to surround the outer circumference of FIG.

In the present embodiment, the metal wires 15 of the glass substrate containing the metal wires are used as lead wires for inputting and outputting to and from an external circuit. Here, the anodic bonding is performed such that the main surface having the piezoresistor 6, the electrode pad 14, and the like faces each other. At this time, the end of the metal wire 15 exposed on the surface of the glass pedestal is aligned with the position of the electrode pad 14, and anodic bonding is performed so that the two are pressed against each other in a vacuum. This anodic bonding is performed using the bonding aluminum pad 16, but the anodic bonding in a vacuum causes the inside of the bonding surface of the chip part 1 to be in the vacuum reference chamber 1.
The semiconductor pressure sensor 7 is formed as a sensor for detecting an absolute pressure. The detected pressure signal is applied to the electrode pad 1
4 and the metal wire 15 pressed into contact with the electrode pad 14 is led to the lower main surface (in the drawing) of the glass pedestal 2 as a lead wire and externally connected via an external connection electrode pad 18 provided for connection to an external circuit. It is output to a circuit (not shown).
The external connection electrode pad 18 is formed by plating, sputtering, or the like.

As described above, the glass substrate containing the metal wire is used as the glass pedestal 2, and the metal wire 15 is attached to the electrode pad 1 of the chip 1.
4, the lead wire is not required, and the lead wire (metal wire 15) connected to the electrode pad 14 of the chip portion 1 is not required.
The configuration is such that the semiconductor pressure sensor is substantially hung below the glass pedestal 2 (external circuit connection surface), so that the package size of the semiconductor pressure sensor can be reduced.

FIGS. 5 and 6 show a third embodiment of the present invention.
Shown in FIG. 5 is a cross-sectional view at the time of anodic bonding, and FIG. 6 is a cross-sectional view at the time of mounting on the metal package 3 after dicing. In the present embodiment, the metal wire 15 of the glass pedestal 2 is used as a lead wire for input / output with an external circuit, and a part of the metal wire 15 is removed by etching to form the pressure introducing hole 5.
It is assumed that.

Here, as in the second embodiment, anodic bonding is performed so that the main surface having the piezoresistor 6, the electrode pad 14, and the like faces each other. At this time, the end of the metal wire 15 exposed on the surface of the glass pedestal is aligned with the position of the electrode pad 14, and the center of the pressure introducing hole 5 is aligned with the center of the diaphragm 5 of the chip 1. Anodic bonding is performed so that both are pressed. This semiconductor pressure sensor is an atmospheric pressure open type sensor. The detected pressure signal is guided to the lower main surface (in the drawing) of the glass pedestal 2 using the electrode pad 14 and the metal wire 15 pressed against the electrode pad 14 as a lead wire, and an external signal provided for connection to an external circuit. It is output to an external circuit (not shown) via the connection electrode pad 18.

FIG. 6 shows the semiconductor pressure sensor wafer and the glass pedestal 2 of FIG. 5 diced and mounted on a metal package 3 having a pipe (pressure introducing hole 5). The external connection pads 18 on the lower main surface of the glass pedestal 2 and the lead electrodes on the metal package 3 are electrically connected by solder 4 or the like. In order to maintain confidentiality (to prevent pressure leakage), for example, an adhesive 2 made of a resin such as silicone is used.
0 is sealed. Note that the external connection electrode pad 18 may be a bump electrode having a projection shape.

As described above, the glass substrate containing the metal wire is used as the glass pedestal 2, and the metal wire 15 is attached to the electrode pad 1 of the chip 1.
4 to form a lead wire, and a metal wire 1
5 is removed by etching, and the removed portion is formed as a pressure introducing hole 5. Therefore, a wire bonding configuration is not required, and the lead wire (metal wire 15) connected to the electrode pad 14 of the chip portion 1 is made of glass. The semiconductor pressure sensor is substantially suspended below the pedestal 2 (external circuit connection surface), so that the package size of the atmospheric pressure release type semiconductor pressure sensor can be reduced.

FIG. 7 shows a method of manufacturing a glass pedestal 2 according to a fourth embodiment of the present invention. In this embodiment, the metal wire 15 of the glass pedestal 2 is removed by etching, another second metal wire 21 is buried or formed in the removed portion, and this second metal wire 21 is It is used as a lead wire (metal wire 15) in the second and third embodiments. As described above, the metal wire of the glass with a metal wire is tungsten or molybdenum, but by using a metal having a lower metal resistance as the second metal wire 21 than these, it becomes a lead wire having a lower electric resistance,
The attenuation of the pressure signal can be suppressed. Note that the second metal 21 may be gold, copper, aluminum, or the like.

As described above, the metal wire 15 of the glass pedestal 2 is removed by etching, and another second metal wire having a low electric resistance is formed in the removed portion by embedding or plating. In addition to the effect that the package size can be reduced, there is an effect that a lead wire having a low electric resistance can be formed to suppress the attenuation of the pressure signal.

[0028]

As described above, according to the first aspect of the present invention, a diaphragm that is displaced by pressure, a semiconductor pressure sensor chip that detects pressure by displacement of the diaphragm, and a semiconductor pressure sensor chip A semiconductor pressure sensor having a glass pedestal mounted thereon and having a pressure introducing hole for introducing pressure to the diaphragm, in a direction substantially orthogonal to the main surface, and with end portions at the first main surface and the second main surface. Is used as the glass pedestal having one or more metal wires having exposed metal wires, so that a pressure introducing hole which can be applied to a semiconductor pressure sensor chip smaller than a conventional size can be formed. At the same time, a semiconductor pressure sensor capable of reducing the package size of the semiconductor pressure sensor can be provided.

In the invention according to claim 2, a part or all of the metal wires of the glass substrate with the metal wires are removed, and the glass pedestal is formed by using the metal wire removing portion as a pressure introducing hole. One or a plurality of semiconductor pressure sensor chips are mounted and joined on the main surface of the pedestal such that the pressure introduction hole and the diaphragm face each other, so that a fine (diameter of about 0.1 to 0.5 mm) is provided. There is an effect that a semiconductor pressure sensor having a pressure introduction hole can be generated.

According to the third aspect of the present invention, since the metal wires of the glass substrate with metal wires are removed by etching, there is an effect that a fine pressure introducing hole can be easily formed.

According to a fourth aspect of the present invention, the material of the metal wire of the glass substrate with the metal wire is molybdenum;
Since the metal wire is removed by etching with a ferric chloride solution, there is an effect that a fine pressure introduction hole can be easily formed.

According to the fifth aspect of the present invention, the metal wires of the glass substrate containing the metal wires are joined to the electrode portions of the semiconductor pressure sensor chip to form lead wires, so that a wire bonding configuration is not required. At the same time, there is an effect that the package size of the semiconductor pressure sensor can be reduced.

In the sixth aspect of the present invention, a part or all of the metal wires of the glass substrate with the metal wires are removed, and another metal is buried in the removed portion to reduce the metal to a semiconductor pressure sensor chip. Since the leads are joined to the electrodes, the package size of the semiconductor pressure sensor can be reduced, and a lead wire having a low electric resistance is formed to suppress the attenuation of the pressure signal. It has the effect of being able to do so.

In the invention according to claim 7, one metal wire or a plurality of metal wires are arranged at predetermined intervals substantially in parallel, and the metal wires are put into molten glass. Solidified to form a solid glass containing the metal wire, and then slicing the solid glass so as to be substantially perpendicular to the metal wire to form a glass substrate with a metal wire, so that the metal wire can be easily formed. There is an effect that a glass pedestal can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a semiconductor pressure sensor according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a glass pedestal portion of the semiconductor pressure sensor according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a cross section of a semiconductor pressure sensor according to a second embodiment of the present invention.

FIG. 4 is a diagram showing one main surface of a semiconductor pressure sensor chip unit according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a semiconductor pressure sensor according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a mounting example of a semiconductor pressure sensor according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating a glass pedestal portion of a semiconductor pressure sensor according to a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating an example of a method of manufacturing a glass pedestal portion according to the semiconductor pressure sensor of the present invention.

FIG. 9 is a diagram showing a cross section of an example of a conventional semiconductor pressure sensor.

FIG. 10 is a diagram showing a cross section of an example of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor pressure sensor (chip part) 2 Glass pedestal 3 Metal package 4 Solder 5 Pressure introduction hole 6 Piezoresistance 7 Diaphragm 8 (Bonding) wire 9 External connection pin 14 Electrode pad 15 Metal wire 16 Aluminum pad for joining 17 Vacuum reference chamber 18 External connection electrode pad

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuyuki Kuzuhara, Inventor Kazuma, Kazuma, Osaka 1048, Matsushita Electric Works, Ltd. (72) Inventor Shigenari Takami 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. (reference)

Claims (7)

[Claims] 1. A diaphragm which is displaced by pressure, a semiconductor pressure sensor chip for detecting pressure by displacement of the diaphragm, and a glass pedestal having the semiconductor pressure sensor chip mounted thereon for introducing pressure into the diaphragm. A semiconductor pressure sensor comprising: a metal wire-containing glass having one or more metal wires in a direction substantially orthogonal to the main surface and having ends exposed on the first main surface and the second main surface. A semiconductor pressure sensor using a substrate as the glass pedestal. 2. A method for removing a part or all of the metal wires of the glass substrate with metal wires, forming the glass pedestal with the metal wire removal part as a pressure introducing hole,
2. The method of manufacturing a semiconductor pressure sensor according to claim 1, wherein one or more semiconductor pressure sensor chips are mounted and joined so that the pressure introduction hole and the diaphragm face each other. 3. The method of manufacturing a semiconductor pressure sensor according to claim 2, wherein the metal wire on the glass substrate containing the metal wire is removed by etching. 4. The semiconductor pressure sensor according to claim 3, wherein a material of the metal wire of the glass substrate containing the metal wire is molybdenum, and the metal wire is etched away by a ferric chloride solution. Manufacturing method. 5. The method according to claim 5, wherein the metal wire of the glass substrate containing the metal wire is
The semiconductor pressure sensor according to claim 1, wherein the semiconductor pressure sensor chip is joined to an electrode portion to form a lead wire. 6. A method for removing a part or all of a metal wire of a glass substrate containing a metal wire, embedding another metal in the removed portion, joining the metal to an electrode portion of a semiconductor pressure sensor chip, and leading a lead. 6. The semiconductor pressure sensor according to claim 5, wherein the pressure sensor is a line. 7. A metal wire or a plurality of metal wires are arranged at predetermined intervals substantially in parallel, the metal wire is put into molten glass, and then the molten glass is solidified to form the metal wire. 7. A glass substrate containing a metal wire, wherein a solid glass containing the metal wire is formed, and then the solid glass is sliced so as to be substantially orthogonal to the metal wire to form a glass substrate containing the metal wire. A method for manufacturing the semiconductor pressure sensor according to any one of the above.