JP2000019042A - Semiconductor sensor and mounting structure - Google Patents

Abstract

(57) [Summary] [Problem] It is small in size, has good mountability, and has good environmental resistance.
In addition, the present invention provides a structure of a semiconductor sensor whose manufacturing cost is low. The external dimensions of an external connection substrate 5 are slightly larger than the pressure-sensitive chip 1. Insulating substrate 2 on external connection substrate 5
Are joined, and the pressure-sensitive chip 1 is joined thereon.
Metal bumps 6 for surface mounting are formed on the lower surface of the external connection substrate 5. Relay contact means is provided on a portion of the upper surface of the external connection substrate 5 which faces the terminal pad section 3, and the terminal pad section 3 and the metal bump 6 are electrically connected via the relay contact means. I have. Further, the joining portions of the external connection substrate 5, the insulating substrate 2, and the pressure-sensitive chip 1 are entirely sealed with the mold resin 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor sensor responsive to physical quantities such as pressure, acceleration, and vibration of a fluid.
In particular, the present invention relates to a microminiature semiconductor sensor and a mounting structure manufactured by a semiconductor micromachine technology.

[0002]

2. Description of the Related Art As is well known, there is a very small semiconductor sensor having the following structure. In this method, a semiconductor substrate made of silicon or the like is formed by applying a semiconductor device manufacturing technology or a micro machine technology, and a small chip is integrally formed with a thin diaphragm in a frame of a thick support frame portion. This chip is called a pressure-sensitive chip, and is combined with an insulating substrate such as glass to be joined. At this time, the diaphragm of the pressure-sensitive chip is opposed to the surface of the insulating substrate at a very small interval. By forming a movable electrode on the diaphragm and a fixed electrode on the insulating substrate, a variable capacitance element is formed by the opposed movable electrode and the fixed electrode at a small interval. Therefore, for example, when the pressure changes on the diaphragm to change the distance, the capacitance between the two electrodes changes. This is the sensor output.

FIG. 1 shows an appearance of a basic structure of a semiconductor sensor (pressure sensor) of this kind. As shown in FIG. 1, the pressure-sensitive chip 1 made of a semiconductor substrate and the insulating substrate 2 are laminated, and the outer dimensions of the insulating substrate 2 are clearly smaller than the outer dimensions of the pressure-sensitive chip 1. And pressure sensitive chip 1
A terminal pad portion 3 of a sensor circuit including the variable capacitance element is provided in a remaining portion (step-like portion) of the pressure-sensitive chip 1 on a bonding surface of the pressure-sensitive chip 1 and the insulating substrate 2. The terminal pad section 3 is electrically connected to an external peripheral circuit.

[0004] A pressure guiding hole is opened in the sensor.
The hole 4 on the sensor side shown in FIG. 1 is an example of a pressure guiding hole.
Pressure acts on the internal diaphragm through the pressure guiding hole. There is also a type in which a pressure guiding hole extending in the thickness direction is also formed on the side of the insulating substrate 2 and pressure is applied from the outside to the opposite surface of the diaphragm through the hole. Since there is various inconveniences in the mounting surface if the sensor main body having the above structure is used, it is usual to mount the sensor body in a suitable package.

In the conventional semiconductor sensor packaging structure, a resin or metal package is separately manufactured (with a lead frame), and the sensor body is housed in the package and fixed with an adhesive or the like. I do. Further, the bonding portion of the sensor body and the lead frame of the package are wire-bonded inside the package. Of course, the package has a passage for introducing the pressure to be detected from the outside into the sensor main body.

[0006]

In the above-mentioned conventional packaging structure, the cost of manufacturing the resin or metal package separately is considerably high, and the assembly work for storing the sensor body in the package is considerable. It also becomes costly. In addition, in a structure in which the sensor body is housed in a separately manufactured package, it is necessary to provide a considerable amount of dimensional margin between the two, so that the external dimensions of the sensor after packaging are large and miniaturization is possible. There was a problem that it was difficult. Furthermore, there are various problems such as poor environmental resistance because the bonding wires connecting the sensor body and the lead frame inside the package and the sensor body itself is opened inside the hollow package. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-mentioned problems, to be small in size, to have good mountability, to have good environmental resistance, and to have a high manufacturing cost. To provide a cheap semiconductor sensor and a mounting structure.

[0008]

In order to achieve the above object, in a semiconductor sensor according to the present invention, a semiconductor substrate having a movable portion that is displaced in accordance with a physical quantity and an insulating substrate are joined, The substrate and the insulating substrate are different from each other in outer dimensions at a joint surface thereof, at least one of the joint surfaces is exposed, and a sensor main body having a terminal pad portion of a sensor circuit at an exposed portion thereof is attached to the sensor main body. External connection board. And
The smaller external dimension of the semiconductor substrate and the insulating substrate is joined to the external connection substrate. At this time, the external dimensions of the external connection board are made larger than the bonding surface with the sensor main body, and the terminal pads are opposed to the bonding surface side surface of the external connection board. A relay contact means is provided on a portion of the terminal pad portion opposite to the portion, and the terminal pad portion can be electrically connected to an external circuit via the relay contact means. Preferably, the portion of the relay contact means is resin-molded (claim 2).

A recess is formed on the surface of the external connection board that is to be joined to the sensor main body, and a lower portion of the board constituting the sensor main body that is bonded to the external connection board is inserted into the recess. The external connection board and the sensor body may be joined (claim 1). Furthermore, the external connection board may be configured using a flexible printed wiring board (claim 4).

In the embodiment, the sensor body has been described as an example applied to a pressure sensor. However, the present invention is not limited to this, and may be an acceleration sensor (vibration sensor) or the like. Also, various types of relay contact means can be used. For example, a metal pin standing upright on an external connection board can be used. Besides, solder, solder balls, various bumps, conductive adhesive (especially anisotropic conductive adhesive is preferable), and conductive pedestal can also be used. As the conductive pedestal, for example, conductive rubber can be used.

According to the present invention, when the sensor main body is mounted on the external connection board, a board having a small external dimension is arranged so as to come to the external connection board side and bonded, contrary to the related art. The pads are opposed to each other, and the interval between them is very short because the thickness is equal to or less than the thickness of the substrate joined to the external connection substrate. Therefore, the terminal pads can be easily electrically connected to the mounting board (the wiring path provided on the mounting board) by the relay contact means as exemplified above. Moreover, unlike the conventional wire bonding, since the distance is very short and they are opposed to each other, the sensor can be configured with a flat area almost the same as the outer dimensions of the sensor body. Further, the thickness in the laminating direction may be about the thickness of the external connection board. That is, the volume occupied by the semiconductor sensor can be reduced as much as possible.

When such a semiconductor sensor is mounted on a mounting substrate, bumps and the like are provided on the non-bonding surface of the external connection substrate in the same manner as other ICs and other electronic components.
Since surface mounting can be performed by reflow processing, batch processing can be performed easily. In other words, a semiconductor sensor that previously could only be mounted individually due to a step based on the difference in the outer dimensions of the semiconductor substrate and the insulating substrate can now be surface-mounted,
Processing efficiency is much improved.

[0013] In particular, in the case of the configuration according to the second aspect, the risk of disconnection or the like is suppressed as much as possible. Also,
According to the third and fourth aspects, the thickness in the stacking direction can be reduced. It should be noted that the depression in claim 4 means that it is only necessary to be one step lower than the surface of the bonding surface, and the presence or absence of the bottom surface does not matter.
In other words, a frame having no bottom surface and, for example, a frame shape having a square shape in plan view can be a mounting substrate of the present invention. And in this case, when the distance between the terminal pad and the mounting board becomes narrow,
The relay contact means may be solder or the like. Further, a conductive rubber, a conductive adhesive (resin), or the like can also be used. In particular, when an anisotropic conductive material is used, the conductive material becomes conductive only in the pressing direction (the laminating direction of the substrates) by pressing, so that a plurality of terminal pads are insulated from each other and bumps on the external connection substrate are provided. Can be conducted. Since the anisotropic conductive material is cured by heating, it also functions as an adhesive.

On the other hand, in the mounting structure of a semiconductor sensor according to the present invention, a semiconductor substrate having a movable portion displaced in accordance with a physical quantity is joined to an insulating substrate, and the semiconductor substrate and the insulating substrate are joined to each other. A mounting structure of a semiconductor sensor having a sensor body having a sensor body provided with a terminal pad portion of a sensor circuit on the exposed portion while varying external dimensions on the surface, and exposing at least one joint surface, A smaller outer dimension of the semiconductor substrate and the insulating substrate is located on the mounting substrate side, and the terminal pads are opposed to the mounting substrate, and a wiring pattern formed on the mounting substrate and the terminal pads are The connection is made directly or via a connecting member (claim 5).
Preferably, a hole is provided in the mounting surface of the mounting board, and a board having a smaller outer dimension of the sensor body is inserted into the hole (claim 6).

In the sensor main body, the substrate having a small external dimension is located on the mounting substrate side, so that the terminal pads provided on the bonding surface side exposed surface of the substrate having the large external dimension face the mounting substrate side. Therefore, since the terminal pattern and the wiring pattern provided on the mounting board face each other, the two can be connected directly or via a connecting member. This also eliminates the need for wine bonding and the like, and occupies a small area.
In particular, according to the structure as described in claim 6, since the small substrate enters the hole, not only the thickness at the time of mounting can be reduced, but also the terminal pad and the wiring pattern can be directly connected. The term “hole” as used herein is a concept including not only a so-called hole having a bottom but also a hole penetrating without a bottom.

[0016]

FIG. 2 shows the structure of a semiconductor sensor according to a first embodiment of the present invention. First, the sensor body used in the present embodiment is a pressure sensor, in which a thin diaphragm is formed on the semiconductor substrate 1 and the diaphragm is opposed to the surface of the insulating substrate 2 at a very small interval. Thereby, the movable electrode provided on the diaphragm,
Since a capacitance corresponding to the distance is generated between the fixed electrodes formed on the insulating substrate, for example, when a pressure acts on the diaphragm to change the distance, the capacitance between the two electrodes changes. Therefore, a variable capacitance element is formed by the two substrates 1 and 2.

Further, since the outer dimensions of the bonding surface of the insulating substrate 2 are smaller, the terminal pads of the sensor circuit including the variable capacitance element are provided on the exposed surface (stepped portion) of the pressure-sensitive chip 1 on the bonding surface side. A part 3 is provided. As described above, the sensor body to be used may have the same configuration as the conventional one.

Here, in the present invention, as shown in the figure, when the sensor main body is joined to the external connection substrate 5, the semiconductor substrate 2 having a small external dimension is joined to the external connection substrate 5. This external connection board is mainly composed of an insulating board, and the external dimensions of the external connection board 5 are set slightly larger than the pressure-sensitive chip 1. A metal bump 6 for surface mounting is formed on the lower surface of the external connection substrate 5.

Since the semiconductor substrate 2 and the external connection substrate 5 are connected as described above, a region not bonded to the insulating substrate 2 is formed on the bonding surface of the external connection substrate 5,
Such a region is made to face the terminal pad 3 provided on the pressure-sensitive chip 1. Thus, in such a region, a gap space is formed between the external connection substrate 5 and the pressure-sensitive chip 1 by a distance corresponding to the thickness of the insulating substrate 2, and the terminal pad 3 exists in the gap space. Will do.

Therefore, the upper surface (bonding surface) of the external connection substrate 5
Is provided with a relay contact means at a portion facing the terminal pad section 3, and the terminal pad section 3 and the metal bump 6 are electrically connected via the relay contact means. In the embodiment shown in FIG. 2, the metal pads 7 erected on the external connection substrate 5 are used as the relay contact means, and the terminal pads 3 and the metal pins 7 are connected via the flip chip 15. Therefore, the external connection board 5 can be placed on the mounting board (not shown), and can be surface-mounted on the mounting board via the metal bumps 6, and can be electrically connected to the wiring pattern of the mounting board via the metal pins 7.

The relay contact means is not limited to the above-described embodiment, but may take various forms as described below. That is, in the second embodiment shown in FIG. 3, since the thickness of the insulating substrate 2 is reduced, a solder or a solder ball 8 can be used as the relay contact means. In the illustrated example, a metal terminal 16 is provided on the facing surface of the external connection substrate 5, and the solder ball 8 is joined to the terminal. Further, when the insulating substrate 2 is made thinner in this way, it is not necessary to use the metal pins 7 as shown in FIG. 2, and instead of the solder balls 8 in FIG. That is, in this case, the flip chip serves as the relay contact means.

Further, instead of making the insulating substrate 2 thin, a pedestal 9 is used for the external connection substrate 5 as in the third embodiment shown in FIG. 4 (the terminal 16 is on the upper surface).
Thereby, connection by the flip chip 15 can be performed.
In this case, the pedestal 9 may be formed of a conductive material. And, the relay contact means in this mode,
The flip chip 15 and the base 9 (in the case of a conductive material) are used. Further, when the base 9 is formed of conductive rubber,
By utilizing the elastic force of the rubber, conduction with the terminal pad can be directly achieved without providing the flip chip 15.

In the fourth embodiment shown in FIG. 5, a recess 5a of a predetermined shape is formed on the upper surface of the external connection substrate 5, and the lower portion of the insulating substrate 2 is fitted into the recess 5a and joined. I do. In this way, the overall height of the sensor structure can be made smaller. In the fifth embodiment shown in FIG. 6, a flexible printed wiring board is used as the external connection board 5. According to this embodiment, the overall height can be further reduced. In each of the fourth and fifth embodiments, the continuity is achieved by using the flip chip 15. However, various configurations such as solder, solder balls, and bumps can be employed as in the above-described examples. .

In any of the embodiments described above, a mold resin 10 such as a silicone resin is applied to the joints of the substrates 1, 2, 5 and is entirely sealed and protected by a resin mold. . Further, as shown in each figure, a through hole 11 is formed in the center of the external connection substrate 5, and external pressure is guided to the diaphragm of the pressure-sensitive chip 1 through the through hole 11 a provided in the insulating substrate 2. I have to. Of course, as shown in FIG. 1, when the pressure is supplied from a hole provided on the joint surface between the insulating substrate 2 and the pressure-sensitive chip 1 or from above the pressure-sensitive chip 1, the through holes 11 and 11a are provided. May not be provided.

FIG. 7 shows a sixth embodiment.
In this embodiment, the unbonded region of the pressure-sensitive chip 1 exists around the insulating substrate 2 (until the fifth embodiment described above, the unbonded region exists only on one side). 3 are located on both sides. With this, the external connection board 5
Are connected to the auxiliary substrate 17 via solder balls 8 as relay contact means on both sides of the substrate. The auxiliary board 17 may be considered as the terminal described in each of the above-described embodiments, or may be considered as a pedestal for raising the bottom, and the auxiliary board 17 may be considered as a part of the external connection board 5. The inside of the auxiliary substrate 17 may be regarded as having the depression 5a.

Then, as shown in the drawing, it is connected to a mounting board 18 via a metal bump 6 formed on the external connection board 5. Such a form of connection to the mounting board 18 is common to the above embodiments.

FIG. 8 shows an example of a separate mounting structure. That is, a sensor body of a type which uses the metal chip 19 as the relay contact means and is connected to the flip chip 15 is used, and conducts it to the external connection board 5. Thereby, a semiconductor sensor is configured. The other corresponding parts equivalent to those of the embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

This is connected to the substrate 22 via the bumps 6, and the substrate 22 is attached to the case 24 with screws 23. As in the case of the external connection board 5, the board 22 and the case 24 are also provided with a pressure introduction hole 26 penetrating in the thickness direction, thereby introducing pressure from the outside. An O-ring 25 is interposed between the external connection substrate 5 and the substrate 22 and around the pressure introducing hole 26 between the substrate 22 and the case 24 to maintain airtightness.

FIG. 9 shows an embodiment of the mounting structure of the semiconductor sensor according to the present invention. Also in the present embodiment, the structure of the sensor body itself used is the same as in each of the above-described embodiments. Then, the insulating substrate 2 having a small external dimension is arranged toward the mounting substrate 18 side. A connection member 28 is provided between the terminal pad 4 provided on the pressure-sensitive chip 1 and the mounting board 18. In the present embodiment, the connecting member 28 is arranged so as to be located in the shape of a flat square and located around the outer periphery of the insulating substrate 2. Then, a glass epoxy double-sided board is used, and both sides are connected by through holes 29. That is, the terminal pad 4 is formed on the wiring pattern 2
8a, and a through hole 29 is connected to the end of the wiring pattern 28a to guide the wiring pattern 28a to the back side of the connecting member 28.
The electrode pads 4 can be guided to the mounting board 18 by locating the wiring pattern of the mounting board 18 at the rear end of the through hole 29.

Further, in this embodiment, a lid-shaped case 30 is connected to the upper surface of the connecting member 28, and the case 30 covers the sensor body. A pressure introducing pipe 30 a is provided on the top surface of the case 30, and a measurement pressure introduced via the pressure introducing pipe 30 a is applied to a diaphragm provided on the pressure-sensitive chip 1.

In the above-described embodiment, a substrate having a flat rectangular shape and vertically opened is used as the connecting member 28. However, the present invention is not limited to this. For example, as shown in FIG. The connecting member 32 may be used. That is, the concave portion 32a is provided on the upper surface of the connecting member 32, and the insulating substrate 1 is inserted into the concave portion 32a. And the connecting member 3
The connection between the terminal pad 4 and a wiring pattern (not shown) provided on the mounting board 18 is established through the through hole 33 provided in the mounting board 18. At both ends of the through hole 33, electrical connection is achieved by using bumps (solder, gold) 35.

FIG. 11 shows still another embodiment.
In this example, the semiconductor sensor is directly mounted on the mounting board 18 without providing a connecting member. That is, the hole 18 a is provided in the mounting board 18. And the hole 18a
A small substrate (a pressure-sensitive chip 1 in this example) of a semiconductor sensor is inserted therein. The terminal pads 4 provided on the large substrate (insulating substrate 2) are directly connected to the wiring patterns (electrode lands) on the mounting substrate 18. In this case, the height can be suppressed lower than that of the substrate shown in FIGS. 9 and 10 described above.

In this embodiment, the hole 1 of the mounting board 18 is used.
The bottom surface of 8a is opened, and the atmospheric pressure serving as the comparative pressure (reference pressure) is applied to the diaphragm 1a through the opening 18b. Also, the upper surface side of the mounting substrate 18 is also covered with the case 30, and the measurement pressure is introduced into the case 30 from the pressure introduction pipe 30 a to apply the measurement pressure to the diaphragm 1 a through the pressure introduction hole 2 a of the insulating substrate 2. ing. The connection between the sensor main body and the mounting board 18 and the connection between the case 30 and the mounting board 18 are made via an adhesive 36.

In each of the embodiments described above, examples are shown in which the present invention is applied to a pressure sensor. However, the present invention is not limited to this, and can be applied to other semiconductor sensors such as an acceleration sensor. Further, the detection method is not limited to the capacitance type, but can be applied to a piezo type or other forms.
Further, in each of the embodiments of the semiconductor sensor, the example has been described in which the pressure-sensitive chip 1 has a larger outer dimension and shape.
The present invention is not limited to this, and there is no problem even if the insulating substrate side is large as in the case shown in FIG.

[0035]

According to the present invention, since the terminal pads and the mounting board (external connection board / mounting board) are opposed to each other, they can be easily connected by the relay contact means. Therefore, unlike the wire bonding, it is not necessary to route the wires to the outside, and the occupied area is about the same as the chip size, and the size can be reduced. Since a general surface mounting method can be adopted to incorporate this sensor into an external peripheral circuit system, high-density mounting can be performed with high efficiency using existing mounting technology. Further, since the core of the sensor and the relay contact portion attached thereto are molded with resin, the environmental resistance is improved, and the entire sensor including the resin-sealed portion by molding can be made smaller than before.

[Brief description of the drawings]

FIG. 1 is a diagram showing a body structure (sensor main body) of a semiconductor sensor to which the present invention is applied.

FIG. 2 is a structural diagram of the semiconductor sensor according to the first embodiment of the present invention.

FIG. 3 is a structural diagram of a semiconductor sensor according to a second embodiment of the present invention.

FIG. 4 is a structural diagram of a semiconductor sensor according to a third embodiment of the present invention.

FIG. 5 is a structural diagram of a semiconductor sensor according to a fourth embodiment of the present invention.

FIG. 6 is a structural diagram of a semiconductor sensor according to a fifth embodiment of the present invention.

FIG. 7 is a structural diagram of a semiconductor sensor according to a sixth embodiment of the present invention.

FIG. 8 is a diagram showing a mounting example of the semiconductor sensor of the present invention.

FIG. 9 is a view showing one embodiment of a mounting structure of a semiconductor sensor according to the present invention.

FIG. 10 is a diagram showing another embodiment of the mounting structure of the semiconductor sensor according to the present invention.

FIG. 11 is a view showing still another embodiment of the mounting structure of the semiconductor sensor according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure-sensitive chip (semiconductor substrate) 2 insulating substrate 3 terminal pad portion 4 hole 5 external connection substrate 6 metal bump 7 metal pin 8 solder ball 9 pedestal 10 mold resin 11 through hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Toya 10 Hanazono Todocho, Ukyo-ku, Kyoto, Kyoto O Inside the Mron Corporation (72) Inventor Koichi Furusawa 10 Hanazono Todocho, Ukyo-ku, Kyoto, Kyoto Inside Mullon Co., Ltd. (72) Koji Yamaguchi, Inventor Koji Kyoto, Kyoto 10th Hanazono Todocho, Omron Co., Ltd. (72) Inventor Taku Masai F-term (reference) 2F055 CC02 DD04 EE23 EE25 FF38 FF43 FF49 GG01 GG13 4M112 AA01 BA07 CA02 CA11 CA13 CA15 DA18 DA20 GA01

Claims (6)

[Claims] 1. A semiconductor substrate having a movable portion displaced in accordance with a physical quantity and an insulating substrate are joined, and the semiconductor substrate and the insulating substrate have different outer dimensions at a joint surface of the two, and at least one of the two has a different outer dimension. A sensor body having a joint surface exposed and a sensor circuit terminal pad provided on the exposed portion; and an external connection board to which the sensor body is attached, wherein the semiconductor substrate and the insulating substrate have smaller outer dimensions. And the external connection substrate are joined, the external dimensions of the external connection substrate are made larger than the joint surface with the sensor body, and the terminal pads and the joint surface side surface of the external connection substrate face each other, Relay contact means is provided at a portion of the external connection substrate opposite to the joint-side surface exposed portion and the terminal pad portion, and an external circuit is connected via the relay contact means. Allows the connection between the the semiconductor sensor. 2. The semiconductor sensor according to claim 1, wherein a portion of said relay contact means is resin-molded. 3. A concave portion is formed on a joint surface of the external connection substrate with the sensor main body, and a lower portion of the substrate constituting the sensor main body, which is bonded to the external connection substrate, is inserted into the concave portion. The semiconductor sensor according to claim 1, wherein the external connection board and the sensor main body are joined in a state. 4. The semiconductor sensor according to claim 1, wherein a flexible printed wiring board is used as the external connection board. 5. A semiconductor substrate having a movable portion displaced in accordance with a physical quantity and an insulating substrate are joined. The semiconductor substrate and the insulating substrate have different outer dimensions at a joint surface of the two, and at least one of the two has a different outer dimension. A mounting structure of a semiconductor sensor having a sensor body having a sensor body provided with a terminal pad portion of a sensor circuit on the exposed portion while exposing a bonding surface, wherein the outer dimensions of the semiconductor substrate and the insulating substrate are The smaller one is located on the mounting board side, and the terminal pad is opposed to the mounting board, and the wiring pattern formed on the mounting board and the terminal pad are connected directly or via a connecting member. Semiconductor sensor mounting structure. 6. The semiconductor according to claim 5, wherein a hole is provided on a mounting surface of said mounting board, and a board having a smaller outer dimension of said sensor body is inserted into said hole. Sensor mounting structure.