JP2000304764A - Semiconductor dynamic value sensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent entrance of dust into a dynamic value detecting part of a sensor chip, with a simple configuration. SOLUTION: A sensor chip 2 comprising an acceleration detecting part 8 of a fine structure is mounted in a mount region of a signal processing chip 3 comprises a signal processing circuit and bonded with an adhesive sheet 16. Electrode pads 9 and 10 of the sensor chip 2 are electrically connected to electrode pads 14 and 15 of the signal processing chip 3 with tape leads 17 and 18 of a film carrier tape 4. At this time, the film carrier tape 4 is provided with a cover part 4b which covers the upper surface part of the acceleration detecting part 8. The acceleration detecting part 8 is recessed to assure a clearance of a required amount against the film carrier tape 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor dynamics device having a sensor chip having a microstructured dynamic quantity detection unit, such as an acceleration sensor or a rate sensor, and a signal processing chip for processing signals from the sensor chip. The present invention relates to a quantity sensor and a method for manufacturing the same.

[0002]

In a semiconductor dynamic quantity sensor of this type, for example, a capacitive acceleration sensor, a sensor chip having an acceleration detecting section is mounted on a signal processing chip having a signal processing circuit, and these are connected by wires. After connecting by bonding, mounting on ceramic package,
Some are configured by sealing. Further, the acceleration detection unit has a fine structure including a movable electrode that is displaced in response to the action of acceleration, and a pair of fixed electrodes that are opposed to the movable electrode with a fine gap therebetween.

[0003] By the way, in the above acceleration sensor,
If dust enters the minute gap between the movable electrode and the fixed electrode of the acceleration detection unit, there is a possibility that the displacement of the movable electrode may be hindered, resulting in malfunction or characteristic failure. Therefore, conventionally, the entire assembling process from the manufacture of the sensor wafer to the mounting and sealing in the ceramic package is performed in a clean environment such as a clean room where the air is purified. However, in order to maintain the entire assembling process in a clean environment as described above, there is a problem that a considerably large-scale facility is required and the operating cost is increased.

In recent years, it has been considered that a cap made of glass or silicon is bonded to the sensor wafer at the level of the sensor chip wafer to prevent dust from subsequently entering the acceleration detecting section. ing. However, in joining the caps in this manner, a material and a process for providing the caps are required, so that the cost is increased and there is a possibility that a stress is applied to the sensor chip at the time of joining to cause a change in characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a semiconductor dynamic quantity sensor and a semiconductor dynamic quantity sensor capable of effectively preventing dust from entering a dynamic quantity detection section of a sensor chip with a simple configuration. It is an object of the present invention to provide a manufacturing method thereof.

[0006]

According to a first aspect of the present invention, there is provided a semiconductor dynamic quantity sensor for electrically connecting a sensor chip to a signal processing chip, and having both ends of an electrode portion of the sensor chip and an electrode pad of the signal processing chip. And a film carrier tape having a tape lead connected to the sensor chip, and the film carrier tape covers the upper surface of the physical quantity detecting section of the sensor chip.

[0007] According to this, since the upper surface of the physical quantity detecting portion of the sensor chip is covered with the film carrier tape, the film carrier tape acts as a cover, so that dust enters the physical quantity detecting portion. Can be suppressed. This makes it possible to perform a process after the process of connecting the film carrier tape to the sensor chip in an environment with a low degree of air purification,
The manufacturing cost can be reduced accordingly. Also, in this case, a film carrier tape for electrically connecting the sensor chip and the signal processing chip can be used as a cover as it is, so that, for example, compared with the case where a glass cap is provided, the process and material costs are reduced. A simple configuration can be achieved without increasing the size.

In this configuration, if the film carrier tape comes into contact with the upper surface of the physical quantity detecting unit, there is a possibility that the displacement of the physical quantity detecting unit may be hindered, or an adverse effect due to static electricity may occur. There is. In view of this, the physical quantity detection unit may be provided so that its upper surface is depressed from the upper surface of the sensor chip (the invention of claim 2), or a tape lead may be provided with respect to the electrode portion of the sensor chip. The connection may be made via bumps of a predetermined height (the invention of claim 3). According to these,
A required amount of clearance can be ensured between the mechanical quantity detection unit and the film carrier tape, and the above-described problem can be prevented.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor dynamic quantity sensor, wherein one end of a tape lead is connected to an electrode section in a form in which a film carrier tape covers a dynamic quantity detection section of a sensor chip; It is characterized in that the step of mounting the sensor chip in the mounting area of the signal processing chip and the step of connecting the other end of the tape lead of the film carrier tape to the electrode pad of the signal processing chip are performed in order.

According to this, first, the step of connecting the sensor chip to the film carrier tape is performed.
It is possible to proceed to the next step while handling the sensor chip in units of a film carrier tape, which is advantageous in handling such as handling. At this stage, dust can be prevented from entering the physical quantity detection unit of the sensor chip already.Therefore, the process after the process of mounting the sensor chip on the signal processing chip is performed in an environment where the degree of air cleaning is low. And the manufacturing cost can be reduced accordingly.

In this case, the sensor chip is mounted on the signal processing chip via an adhesive sheet disposed on the back side, and the adhesive sheet is attached to the back side at the stage of the sensor wafer. (The invention of claim 5). According to this, at the stage of the sensor wafer, the back surface of the sensor chip is covered with the adhesive sheet, so that it is possible to prevent dust from intruding from the back surface to the subsequent mechanical quantity detection unit, which is more effective.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a capacitive acceleration sensor will be described below with reference to the drawings. FIG. 1 shows a configuration (a state before being mounted on a package) of an acceleration sensor 1 as a semiconductor dynamic quantity sensor according to the present embodiment. The acceleration sensor 1 includes a sensor chip 2, a signal processing chip 3, and a film carrier tape 4.

The sensor chip 2 is formed, for example, on a support substrate 5 having a rectangular opening made of single crystal silicon and having a rectangular opening 5a at the center thereof through an insulating film 6 to form a rectangular single crystal silicon. It has a layer 7. Then, as shown in FIG. 2, the single-crystal silicon layer 7
It has a frame portion 7a formed in a substantially rectangular frame shape, and an acceleration detecting portion 8 as a physical quantity detecting portion of a fine structure inside the frame portion 7a. The acceleration detecting section 8 is provided in a rectangular area corresponding to the opening 5a. Also,
On the left side of the frame portion 7a, three electrode pads 9 serving as connection electrode portions are provided side by side in the front-rear direction, and on the right side portion there are provided three electrode pads 9 serving as electrode portions symmetrically. A pad 10 is provided.

As shown in FIG. 2, the acceleration detecting section 8 includes a movable electrode section 11 which is displaced in accordance with the action of acceleration,
It has a pair of fixed electrode portions 12 and 13. The movable electrode portion 11 has left and right ends supported by the frame portion 7a, and a beam portion in the form of a rectangular frame elongated in the front-rear direction at the left and right ends of the mass portion 11a extending in the left-right direction through the center of the acceleration detection portion 8. 11b, and a plurality of narrow-width movable electrodes 11c extending in a comb-like manner from the mass portion 11a forward and rearward, respectively. The movable electrode portion 11 (left end side of the mass portion 11a) is electrically connected to the electrode pad 9 located at the center of the left side of the frame portion 7a.

On the other hand, the fixed electrode portion 12 is a fixed electrode wiring portion 1 extending in the left-right direction on the front side of the frame portion 7a.
It comprises a plurality of narrow fixed first electrodes 12b extending in a comb-like manner from the rear side 2a. The fixed electrode 12b is provided immediately to the left of the movable electrode 11c in parallel with a small gap therebetween. The fixed electrode portion 12 (the left end portion of the fixed electrode wiring portion 12a)
Is electrically connected to the front electrode pad 9 on the left side of the frame 7a.

Further, the fixed electrode portion 13 is connected to the frame portion 7.
A plurality of narrow second fixed electrodes 13b extending in a so-called comb-like manner from the fixed electrode wiring portion 13a extending in the left-right direction on the rear side of the fixed electrode 13a. The fixed electrode 13b is provided immediately adjacent to the movable electrode 11c in parallel with a small gap therebetween. The fixed electrode portion 13 (the left end of the fixed electrode wiring portion 13a) is electrically connected to the electrode pad 9 on the rear side of the left side of the frame portion 7a.

Thus, between the movable electrode portion 11 (movable electrode 11c) and the fixed electrode portion 12 (first fixed electrode 12b), and between the movable electrode portion 11 (movable electrode 11c) and the fixed electrode portion 13 Capacitors are respectively formed between the second fixed electrode 13b and the second fixed electrode 13b, and the capacitances of these capacitors are changed differentially according to the displacement of the movable electrode unit 11 due to the action of acceleration. Thus, the acceleration can be extracted as a change in the capacitance value.
In the present embodiment, as shown in FIG.
Is provided so as to be slightly recessed from the upper surface of the sensor chip 2 (the upper surface of the frame portion 7a of the single crystal silicon layer 7), for example, by etching the entire upper surface.

On the other hand, the signal processing chip 3 has a rectangular plate shape slightly larger than the sensor chip 2 and, although not shown, a signal processing circuit for processing a signal from the acceleration detector 8 of the sensor chip 2. More specifically, a capacitor for converting a capacitance change into a voltage change and amplifying it to a predetermined output is used.
It is configured to include a voltage conversion unit, a filter, a signal amplification unit, and the like. As shown in FIG. 1, the center of the upper surface of the signal processing chip 3 is a mounting area on which the sensor chip 2 is mounted, and the left and right sides of the upper surface of the signal processing chip 3 Corresponding to the electrode pads 9 and 10 of the sensor chip 2, there are provided electrode pads 14 and 15 (only one is shown) for making electrical connection therewith, respectively.

As will be described later in the description of the manufacturing method, the sensor chip 2 is mounted on a mounting area on the upper surface of the signal processing chip 3 and is attached to the signal processing chip 3 by an adhesive sheet 16 provided on the back side. It is designed to be glued. Then, each electrode pad 9 of the sensor chip 2
The electrical connection between the signal processing chip 3 and the respective electrode pads 14 and the electrical connection between the sensor chip 2 and the respective electrode pads 15 of the signal processing chip 3 are performed by the film carrier tape 4. It is supposed to be.

Now, the film carrier tape 4 is
As shown in FIG. 3, a frame portion 4 a having a horizontally long rectangular shape,
It has a rectangular cover portion 4b provided inside thereof and having a size slightly smaller than that of the sensor chip 2 by one. On the lower surface thereof, three tape leads 17 for connecting the electrode pads 9 and the electrode pads 14 are provided, corresponding to their positions, on the left side of the cover 4b and the frame. 3 is provided so as to extend between the left side portion of the shape-like portion 4a, and is connected to each of the electrode pads 10 and each of the electrode pads 15.
The tape leads 18 of the book are provided so as to extend between the right side of the cover 4b and the right side of the frame 4a corresponding to the positions.

As shown in FIG.
Is connected to the electrode pad 9 via the bump 19 and the other end (left end) is connected to the electrode pad 1.
4, and one end (left end) of the tape lead 18 is connected to the electrode pad 10 via the bump 19, and the other end (right end) is connected to the electrode pad 15. The electrical connection between the sensor chip 2 and the signal processing chip 3 is made.

At this time, the cover 4b of the film carrier tape 4 covers the upper surface of the acceleration detector 8 of the sensor chip 2. In addition, the acceleration detecting section 8 is provided in a depressed form, and the film carrier tape 4 is arranged so as to be lifted from the upper surface of the sensor chip 2 by the height of the bumps 19, so that acceleration detection can be performed. Upper surface of part 8 and film carrier tape 4
A required amount of clearance is secured between the cover portion 4b and the cover portion 4b.

The film carrier tape 4 is provided in the form of a long roll in a state where a plurality of the film carrier tapes are connected in the horizontal direction in FIG. 3 (see FIGS. 4C and 4D), and is cut later. So that they can be separated. Although not shown,
The acceleration sensor 1 is mounted in, for example, a ceramic package (or a metal package), and is provided as a product after being hermetically sealed.

Next, a procedure for manufacturing the acceleration sensor 1 will be described with reference to FIG. FIG. 4 shows a manufacturing procedure of the acceleration sensor 1 according to the present embodiment in order.
First, as shown in FIG. 4A, a sensor wafer 20 having a large number of sensor chips 2 is manufactured by, for example, wafer processing on an SOI wafer. In this case, SOI
The acceleration detecting unit 8 is formed on the wafer by using a micromachining technique, and circuits such as electrode pads 9 and 10 and wiring are formed by a known process. Further, bumps 19 are formed on the electrode pads 9 and 10. It is formed. Also,
As described above, the acceleration detection unit 8 performs the etching by
The upper surface is formed to be slightly recessed from the upper surface of the sensor chip 2.

Then, as shown in FIG. 4B, a step of attaching a large adhesive sheet 16 to the entire back surface of the sensor wafer 20 is executed. With this, each sensor chip 2
Is covered with the adhesive sheet 16 to prevent dust from entering the acceleration detector 8 from the back side. Thereafter, a dicing step of cutting the sensor wafer 20 into individual sensor chips 2 is performed. In this cutting step, the adhesive sheet 16 is also divided into individual pieces at the same time, and as shown in FIG. 4C, each sensor chip 2 is divided into a state having the adhesive sheet 16 on the back side. You.

Next, as shown in FIG. 4D, a bonding step of mounting and bonding each sensor chip 2 to the film carrier tape 4 is performed. In this step, a known T is applied to the long film carrier tape 4.
Using the AB technology, the electrode pads 9 of each sensor chip 2,
10 (bump 19) and one end of each of the tape leads 17 and 18 of the film carrier tape 4 are bonded. At this time, the cover 4b of the film carrier tape 4 is configured to cover the upper surface of the acceleration detector 8 of each sensor chip 2. Note that at least the steps up to this point are performed in a clean room or the like with a high degree of cleanliness of the air, so that the intrusion of dust into the acceleration detector 8 is prevented.

Thereafter, as shown in FIG. 4 (e), the film carrier tape 4 is cut (punched) into individual pieces, and the sensor chip 2 having the film carrier tape 4 on the upper surface side.
Is obtained. Then, as shown in FIG. 4F, a process of mounting the sensor chip 2 on the mounting area of the signal processing chip 3 and bonding the sensor chip 2 with the adhesive sheet 16 on the back side is performed. Subsequently, a step of connecting the other ends of the tape leads 17 and 18 of the film carrier tape 4 to the electrode pads 14 and 15 of the signal processing chip 3 is executed.

Thus, as shown in FIG. 1, the electrical connection between the sensor chip 2 and the signal processing chip 3 is made by the tape leads 17 and 18 of the film carrier tape 4. Cover part 2
Thus, the acceleration sensor 1 in which the upper surface of the acceleration detector 8 is covered by b is obtained. Thereafter, steps of mounting and sealing the acceleration sensor 1 in a ceramic package are performed.

In the acceleration sensor 1 configured as described above, the upper surface of the acceleration detector 8 of the sensor chip 2 is covered with the cover 4b of the film carrier tape 4 so that dust can enter the acceleration detector 8. This prevents the sensor from malfunctioning by preventing dust from being trapped in a minute gap between the movable electrode 11c and the fixed electrodes 12b and 13b of the acceleration detection unit 8 and causing malfunction. The step after the step of connecting the film carrier tape 4 to the chip 2 can be performed in an environment where the degree of air cleaning is low.

In this case, the film carrier tape 4 for electrically connecting the sensor chip 2 and the signal processing chip 3 can be used as a cover as it is, which is different from a conventional case where a glass cap is provided. In addition, no special process or material is required, and the cost can be reduced. Therefore, according to the present embodiment, with a simple configuration, it is possible to effectively prevent dust from entering the acceleration detection unit 8 of the sensor chip 2, and to reduce the manufacturing cost. Can be obtained.

In this embodiment, the acceleration detecting section 8 is provided in a form depressed from the upper surface of the sensor chip 2, and the film carrier tape 4 is lifted from the upper surface of the sensor chip 2 by the bumps 19. 8 and the cover 4b of the film carrier tape 4, a required amount of clearance is ensured, so that the film carrier tape 4 comes into contact with the upper surface of the acceleration detecting section 8 and hinders the displacement of the movable electrode section 11. In addition, it is possible to obtain an advantage that defects such as an adverse effect due to static electricity or the like can be prevented.

According to the method of manufacturing the acceleration sensor 1 of this embodiment, the sensor chip 2 is first bonded to the long film carrier tape 4 and then mounted on the signal processing chip 3. , The sensor chip 2 can be advanced to the next process while handling the film carrier tape 4 as a unit, which is advantageous in handling such as handling.
Can be performed in an environment with a low degree of air purification. Further, an adhesive sheet 1 for bonding the sensor chip 2 to the signal processing chip 3
6 is adhered at the stage of the sensor wafer 20, so that dust can be effectively prevented from entering the acceleration detector 8 from the back surface side.

In the manufacturing method of the above-described embodiment, the large adhesive sheet 16 is attached at the stage of the sensor wafer 20, but after the sensor chip 2 is divided into individual pieces, it is cut into small pieces. Alternatively, the sensor chip 2 may be bonded to the signal processing chip 3 using a liquid (gel) adhesive or the like without using the adhesive sheet. good. Then, after bonding the sensor chip 2 to the long film carrier tape 4, the film carrier tape 4 may be re-rolled and supplied separately instead of being cut in-line. In this case, it is also possible to provide a conductive pattern for antistatic on the film carrier tape.

Further, in the above embodiment, the acceleration detecting section 8 is provided so as to be depressed from the upper surface of the sensor chip 2. However, the acceleration detecting section is provided flush with the upper surface of the sensor chip, and the height of the bump 19 is increased. A required amount of clearance may be ensured between the acceleration detection unit and the film carrier tape only by setting the distance. In addition, the present invention is not limited to the acceleration sensor, and the present invention can be applied to a wide range of semiconductor dynamic quantity sensors having a fine-structure dynamic quantity detection unit such as a rate sensor. It can be implemented.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a longitudinal sectional front view of an acceleration sensor.

FIG. 2 is a plan view of a sensor chip.

FIG. 3 is a plan view of a film carrier tape.

FIG. 4 is a view showing a manufacturing process in order.

[Explanation of symbols]

In the drawings, 1 is an acceleration sensor (semiconductor dynamic quantity sensor), 2
Is a sensor chip, 3 is a signal processing chip, 4 is a film carrier tape, 4b is a cover portion, 8 is an acceleration detecting portion (dynamic quantity detecting portion), 9 and 10 are electrode pads (electrode portions), 11
Denotes a movable electrode unit, 12 and 13 denote fixed electrode units, 14 and 15 denote electrode pads, 16 denotes an adhesive sheet, 17 and 18 denote tape leads, 19 denotes bumps, and 20 denotes a sensor wafer.

Claims (5)

[Claims] A sensor chip having a microstructured physical quantity detecting section and a connection electrode section, a mounting area on which the sensor chip is mounted, and an electrode pad electrically connected to the electrode section. In a semiconductor dynamic quantity sensor including a signal processing chip that processes a signal from a physical quantity detection unit, an electrical connection between the sensor chip and the signal processing chip,
Both ends are formed by a film carrier tape having tape leads connected to the electrode portion and the electrode pad, respectively, and the film carrier tape covers the upper surface portion of the physical quantity detecting portion of the sensor chip. A semiconductor dynamic quantity sensor characterized by the above-mentioned. 2. The semiconductor dynamic quantity sensor according to claim 1, wherein the physical quantity detection unit is provided so that an upper surface thereof is recessed from an upper surface part of the sensor chip. 3. The semiconductor dynamic quantity sensor according to claim 1, wherein the tape lead is connected to an electrode portion of the sensor chip via a bump having a predetermined height. 4. The method for manufacturing a semiconductor dynamic quantity sensor according to claim 1, wherein the film carrier tape covers a physical quantity detection unit of the sensor chip. Connecting one end of the lead to the electrode portion; mounting the sensor chip in a mounting area of the signal processing chip; and connecting the other end of the tape lead of the film carrier tape to an electrode pad of the signal processing chip. A method of manufacturing a semiconductor dynamic quantity sensor, wherein the steps of: 5. The sensor chip is mounted on the signal processing chip via an adhesive sheet disposed on the back side thereof, and the adhesive sheet is attached to the back side at the stage of the sensor wafer. The method for manufacturing a semiconductor dynamic quantity sensor according to claim 4, wherein