JPH1183655A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the transmission of an external stress to a semiconductor sensor chip by connecting and supporting a conductor part of the semiconductor sensor chip to a conductor part of a tape bonder, and fixing a lead pin supported at a header base to the conductor part of the tape bonder. SOLUTION: A base 3 is fixed to a lower part of a storage chamber 2 formed at the center of a header 1 which is to be fixed to a fluid pressure measuring part of various kinds of apparatuses. Conductor parts are formed at leading ends of a plurality of lead pins 4 fixed penetrating the base 3, to which conductor parts at a peripheral part of a tape bonder 5 are connected and fixed. A semiconductor sensor chip 6 is supported and suspended by the conductor parts via the tape bonder 5 to the lead pins 4. Accordingly a stress or the like because of a difference of thermal expansions between the semiconductor sensor chip 6 and various members such as the header 1, base 3, etc., is absorbed particularly by the tape bonder 5 of resin film and not transmitted to the semiconductor sensor chip 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor sensor for detecting an absolute pressure such as water pressure, hydraulic pressure, refrigerant pressure, etc., and more particularly, to a semiconductor type pressure sensor chip which does not use an adhesive when fixing it, and reduces stress from a header. It is an object of the present invention to provide a semiconductor pressure sensor that avoids the problem.

[0002]

2. Description of the Related Art In a semiconductor pressure sensor, a piezoresistive layer is provided on the surface of a diaphragm formed of a semiconductor chip such as silicon, and the pressure applied to the diaphragm is converted into an electric signal using a change in the specific resistance of the piezoresistive layer. Air conditioners using compressors, or for home appliances such as refrigerators, for detecting the refrigerant pressure of vehicle air conditioners,
It is used in a wide range of fields, such as for hydraulic pressure detection of hydraulic machines, power steering of civil engineering machines, trucks and the like, and for detection of brake oil pressure, as well as for medical use, industrial measurement, and the like.

In a conventional semiconductor pressure sensor, FIG.
As shown in FIG. 3, a base 32 is fixed to a storage chamber 31 formed at the center of the header 30. To prevent various stresses from being transmitted from the base to the semiconductor sensor chip on the base 32, a glass base is used. Alternatively, a semiconductor sensor chip 34 is provided via a pedestal 33 made of silicon. The lead wire 35 from the semiconductor sensor chip 34 is connected to the tip of a lead pin 36 provided through the base 32. In the semiconductor pressure sensor, the semiconductor sensor chip 34
In particular, the base 32 and the pedestal 33, and the pedestal 33 and the semiconductor sensor chip 3
It is necessary to appropriately select the material of the base material 4 and to employ various attachment means.

In the above-described semiconductor pressure sensor, the pressure applied to the semiconductor sensor chip 34 is converted into an electric signal and output. When the semiconductor sensor chip 34 is used for absolute pressure measurement, for example, 4, the lower surface of the semiconductor sensor chip 34 is air-tightly fixed to the pedestal 33, thereby forming a chamber 40 on the lower surface of the semiconductor sensor chip 34.
There is an absolute pressure sensor 41 that measures the pressure of the fluid to be measured acting on the upper surface of the semiconductor sensor chip 34 as an absolute pressure by making the pressure of the semiconductor sensor chip 34 vacuum. Such an absolute pressure sensor is suitable for measuring the pressure in a sealed space such as a refrigerant circuit.

[0005] For example, as shown in FIG.
And a pedestal 33, and a through hole 42 communicating with the chamber 40 on the lower surface of the semiconductor sensor chip 34 is provided.
From the first pressure to the lower surface of the semiconductor pressure sensor, and a second pressure as a measured pressure is applied to the upper surface of the semiconductor pressure sensor to measure a relative pressure of the measured pressure with respect to the first pressure. There are also sensors. For example, the relative pressure sensor as described above is suitable because the atmospheric pressure is added when measuring the water level in the released tank.

In the above semiconductor pressure sensor, when the semiconductor sensor chip 34 is mounted, the semiconductor sensor chip 3
In order to fix the pedestal 33 fixing the 4 to the base 32, for example, an adhesive 43 such as a silicon-based or epoxy-based adhesive is used. That is, when fixing this portion, it is necessary to ensure that the portion is fixed and to reduce stress such as stress due to a difference in thermal expansion transmitted from the header 30. A system adhesive or the like is used.

In such a semiconductor pressure sensor, when the pressure measuring fluid is used in a state of being in direct contact with these sensor portions, the type of the fluid to be measured depends on the adhesive or the sensor chip. Therefore, the fluid is not limited to a fluid having no corrosive action. On the other hand, when it is necessary to measure a gas or a liquid having a corrosive action on these adhesives or the semiconductor sensor chip 34, FIG.
As shown in FIG.
Is fixed in the storage chamber 31 for storing the semiconductor sensor chip 34 on the lower surface of the diaphragm 44, and the pressure of the fluid to be measured directly acting on the upper surface of the diaphragm 44 is reduced in the storage chamber 31 on the lower surface of the diaphragm 44. The pressure of the corrosive fluid is measured by transmitting the pressure to the semiconductor sensor chip 34 through the oil. In the case of filling the oil in this way, as the adhesive,
Since the silicone-based adhesive swells with oil, an epoxy-based adhesive has been used.

On the other hand, in the above-described semiconductor pressure sensor, in the relative pressure sensor, when the semiconductor sensor chip is fixed, it is very important to maintain the airtightness of the bonding portion between the semiconductor sensor chip and the header. On the other hand, in the absolute pressure type sensor, while maintaining the airtightness of the vacuum chamber is important, the airtightness of the bonded portion between the pressure sensor chip and the header is not required.

[0009]

In the conventional semiconductor pressure sensor as described above, when an epoxy adhesive is used for fixing the sensor chip, the curing temperature of the adhesive is as high as 150 ° C. to 200 ° C. Further, since the hardness after curing was high, the stress of the header 30 was easily transmitted to the semiconductor sensor chip. As a countermeasure, the height of the pedestal 33 made of glass or silicon is increased, or the stress is reduced by providing an appropriate groove 46 in the pedestal 33 as shown in FIG. 6, thereby increasing the cost of the sensor. Was a factor.

In the above-mentioned semiconductor pressure sensor,
In order to absorb the difference in thermal expansion between the semiconductor sensor chip 34 and the header 30, in particular, the base 32, the pedestal 33, and the pedestal 33
In addition, it is necessary to appropriately select the material of the semiconductor chip 34 and the semiconductor sensor chip 34, to adopt various attachment means, and to use a sophisticated attachment technique.

Therefore, the present invention utilizes the fact that in the absolute pressure sensor, as described above, although the airtightness of the vacuum chamber is important, the airtightness of the bonded portion between the pressure sensor chip and the header is not required. It is another object of the present invention to provide a semiconductor pressure sensor which has a simple structure and does not require a special mounting technique and does not transmit external stress to the semiconductor sensor chip.

[0012]

According to the present invention, in order to solve the above-mentioned problems, the conductor of the semiconductor sensor chip is connected to and supported by the conductor of the tape bonder, and the conductor of the deep bonder is supported by the base of the header. The semiconductor pressure sensor is configured to measure the absolute pressure by fixing the lead pins to support the semiconductor sensor chip with respect to the base.

In the present invention, since the semiconductor sensor chip is configured as described above, the semiconductor sensor chip is suspended from the base via the tape bonder supported by the lead pin, so that the semiconductor sensor chip is supported by a header or the like supporting the base. The stress due to the difference in thermal expansion between various members having different thermal expansion from the semiconductor sensor chip, such as the thermal expansion of the member, the thermal expansion of the base, etc., or the stress from their supporting members, etc. The stress is absorbed and these stresses are not transmitted to the semiconductor sensor chip. Further, since there is no need to use an adhesive used for supporting a semiconductor sensor chip as in the related art, it is not necessary to consider corrosion of the semiconductor sensor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the structure of a semiconductor pressure sensor according to the present invention will be described with reference to FIG. A storage chamber 2 is formed in the center of a header 1 fixed to a fluid pressure measurement part of various devices, and a base 3 is fixed to a lower portion of the storage chamber 2. A plurality of lead pins 4 penetrate and are fixed to the base 3. At the tips of the lead pins, a lead wire portion is formed on a resin film by copper plating or the like, and is frequently used in a normal semiconductor component assembly factory. A conductor portion around the well-known tape bonder 5 is connected and fixed. In addition, a conductor portion of the semiconductor sensor chip 6 is connected to a conductor portion located substantially at the center of the tape bonder 5. Thereby, the semiconductor sensor chip 6 is supported by the lead pins 4 fixed to the base 3 in a suspended state via the tape bonder 5.
The upper portion of the storage chamber 2 of the header 1 is sealed by a diaphragm 7. Silicon oil is injected into the storage chamber 2 from a hole 8 provided in the header 1, and the hole 8 is sealed with a ball 10. A semiconductor pressure sensor 11 is configured by filling the storage chamber with silicon oil.

In manufacturing such a semiconductor pressure sensor 11, as shown in FIG. 2 (a), a plurality of Al pads 12 serving as conductive portions of a pressure sensor circuit protruding from a semiconductor sensor chip 6 are formed. Then, the tip of the gold (Au) wire 14 whose periphery is covered by the needle 13 is hung down, and the ultrasonic wave is applied to the needle to melt the Au, thereby forming the Au bump 15 on the aluminum (Al) pad. After forming the Au bumps 15 on all the Al pads, an inspection is performed to determine whether the bumps 15 are formed properly.

Next, a film made of a synthetic resin such as polyimide, which is frequently used in a normal semiconductor manufacturing plant, is designed for connecting the semiconductor sensor chip, as shown in FIG.
The tape bonder is pulled out from the reel around which the tape 17 of the tape bonder 16 is wound as shown in (b). Guides 1 are provided on both side edges of the tape bonder 16 in the same manner as a normal one.
8, a semiconductor sensor chip mounting hole 20 is provided at the center, and a cutout 21 is provided around the hole. A conducting wire portion formed by plating a copper foil provided on the surface of the synthetic resin film is formed in a flat portion 22 surrounded by the cutout portion 21. A large number of such patterns 23 are arranged on the tape 17 of the tape bonder 16.

Next, as shown in FIG. 2 (c), the semiconductor sensor chip 6 on which the bumps 15 are formed as described above is inserted into the mounting holes 17 in one pattern 23 of the tape bonder 16 as described above. The side on which the bumps 15 are formed is brought into contact. At this time, both the conductor portions are designed and manufactured so as to match. Thereby, the semiconductor sensor chip 6
The bumps 15 of the tape bonder 16 and the conductor portions 24 of the tape bonder 16 are aligned, and an IC bonding tool 25 is applied from the opposite side of the tape bonder, and heat is applied at 470 ° C. to 510 ° C. As a result, Au (gold) forming the bumps 15 forms a gold eutectic and joins them. Thereafter, an inspection is performed to determine whether or not this bonding has been properly performed.

Next, as shown in FIG. 2D, the tape bonder 16 to which the semiconductor sensor chip has been joined is cut off at the connection portion of the cut-out portion 21, and
Then, the chip unit 26 is separated. With respect to the conductor portion formed on the flat portion 22 of the tape bonder 16 in the separated chip unit 26, FIG.
Au bumps are formed by a method similar to the method shown in (a) (not shown).

On the other hand, with respect to the header 1, a base 3 is fixed to the lower part of the storage room 2 formed at the center.
A header unit 27 fixed through the plurality of lead pins 4 is manufactured in advance. The position of the lead pin 4 is set at a position corresponding to the Au bump on the conductor formed on the tape bonder. Accordingly, when the chip unit 26 is mounted on the tip of the lead pin 4, the tip of the lead pin and the position of the AU bump coincide with each other, and in this state, an IC bonding tool is used similarly to the method shown in FIG. Au is melted and both are joined. This state is shown in FIG.

Next, as shown in FIG. 2 (F), the upper surface of the storage chamber 2 of the header 1 is fixed to the diaphragm 28 by welding or the like. After that, oil such as silicone oil is injected from the hole 8 of the header 1 opened to the storage chamber,
After filling the oil, the ball 10 is pressed into the outside of the hole 8 to seal the oil in the storage chamber. Thereby, an absolute pressure type semiconductor pressure sensor is manufactured.

In the above embodiment, an example was shown in which an Au bump was formed on the conductor of the semiconductor sensor chip when the conductor of the semiconductor sensor chip was joined to the conductor of the tape bonder. An Au bump may be formed and both may be joined. In addition, when bonding the tape bonder and the lead pin, in the above embodiment, an example was shown in which an Au bump was formed on the tape bonder side.
A bump may be formed on the conductive portion of the tape bonder, and the two may be joined. In addition, when bonding the tape bonder and the lead focus, the above embodiment shows an example in which the Au bumps are formed and connected. However, solder such as cream solder is applied to one of the conductive wire portion of the tape bonder and the tip of the lead pin. After the two are overlaid, they can be joined by heating.

It is preferable to use a thermoplastic resin as a film serving as a base of the tape bonder used in the semiconductor pressure sensor. Further, as a copper foil provided on a film serving as a base, an electrolytic copper foil is preferable. Further, it is preferable to use gold or a metal made of tin and zinc as a plating material formed thereon.

[0023]

According to the present invention, since the semiconductor sensor chip is configured as described above, the semiconductor sensor chip is suspended from the base via the tape bonder supported by the lead pins, so that the header supporting the base is supported. Thermal expansion of members such as
The stress due to the difference in thermal expansion between various members having different thermal expansion from the semiconductor sensor chip, such as the thermal expansion of the base, or the stress from their supporting members is absorbed by the tape bonder portion made of a resin film. No stress is transmitted to the semiconductor sensor chip. Further, since there is no need to use an adhesive used for supporting a semiconductor sensor chip as in the related art, it is not necessary to consider corrosion of the semiconductor sensor. Also, in the absolute pressure type sensor, while maintaining the airtightness of the vacuum chamber is important, the airtightness of the adhesive portion between the pressure sensor chip and the header is not required, so that it has a simple structure and special A semiconductor pressure sensor that does not transmit external stress to the semiconductor sensor chip without requiring any mounting technology can be provided.

Also, since the tape sensor is used to suspend the pressure sensor chip in silicon oil and use an adhesive for fixing the pressure sensor chip, the pressure sensor chip is not affected by the stress from the header, and the pressure is accurately adjusted. Detection is possible. The filled oil has a damping effect on the TAB tape and can withstand mechanical vibrations and shocks. Furthermore, since the pressure sensor chip does not need to be bonded to the header,
No mechanical or thermal stress due to joining. Therefore, there is no need to use a glass pedestal for stress relaxation,
The structure of the pressure sensor chip is simplified, and a low-cost pressure sensor can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor pressure sensor according to an embodiment of the present invention.

FIG. 2 is a process chart showing a method of manufacturing the semiconductor pressure sensor of FIG.

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

FIG. 4 is a cross-sectional view of a conventional absolute pressure type semiconductor pressure sensor.

FIG. 5 is a sectional view of the relative pressure type semiconductor sensor.

FIG. 6 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Header 2 Storage room 3 Base 4 Lead pin 5 Tape bonder 6 Semiconductor sensor chip 7 Diaphragm 8 Hole 10 Ball 11 Semiconductor pressure sensor

Claims (5)

[Claims] 1. The semiconductor sensor chip is connected to a conductor portion of a tape bonder by connecting and supporting the conductor portion of the semiconductor sensor chip, and a lead pin supported by a base of a header is fixed to the conductor portion of the deep bonder. A semiconductor pressure sensor characterized by being configured to measure an absolute pressure by supporting the semiconductor pressure sensor. 2. The method according to claim 1, wherein a pump is formed on one of the conductor portion of the tape bonder and the conductor portion of the semiconductor sensor chip, and the two are connected by heating and fusing at the bump portion.
A semiconductor pressure sensor according to claim 1. 3. The semiconductor pressure sensor according to claim 1, wherein a tape bonder to which the semiconductor sensor chip is connected and a lead pin are connected by a bump. 4. A tape bonder to which a semiconductor sensor chip is connected and a lead pin are connected by soldering.
Alternatively, the semiconductor pressure sensor according to claim 2. 5. Sealed with a diaphragm under pressure,
The semiconductor pressure sensor according to any one of claims 1 to 4, wherein silicon oil is filled in a chamber containing the semiconductor sensor chip.