JPH07283364A - Electronic device and its manufacture - Google Patents

Abstract

PURPOSE:To realize a structure in which chips can be connected electrically and mechanically at the same time. CONSTITUTION:A semiconductor image sensor device is provided with a drive substrate 3 on which a plurality of semiconductor image sensor chips 1 and semiconductor drive chips 2 are mounted and with connection chips 4 by which the semiconductor image sensor chips 1 are connected to each other and by which the semiconductor image sensor chips 1 are connected to the drive substrate 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device including a plurality of semiconductor chips such as a computer and a semiconductor image sensor device. A semiconductor image sensor device taken as an example thereof is applied to not only visible light, infrared light, and ultraviolet light, but especially to those used for measurement of X-rays, radiation, and charged particles, such as photodiodes, photodiode arrays, and photosensors. , A microstrip sensor, a double-sided microstrip sensor, a radiation sensor, a semiconductor photosensor, a semiconductor imaging device, and the like. Here, outputting a signal by receiving such light or radiation is referred to as detecting, and a portion to be detected is referred to as a light receiving surface area or a photo sensor.
Further, a device for taking out a signal detected by the arranged ones as two-dimensional information (image) is called an image sensor device. Although these devices may fulfill their functions with only one sensor chip, the present invention deals with the case where a plurality of sensor chips are mechanically and electrically integrated into one body. The present invention relates to a structure in which all the components function as a semiconductor image sensor device. (Hereinafter, the above-mentioned device is abbreviated as a multi-chip mounting type semiconductor image sensor device.)

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field,
The structures shown in FIGS. 13 to 14 are known.
Here, FIG. 14 is a perspective view of the conventional example shown in FIG. 13 viewed from the back side. In the example shown here, four semiconductor image sensor chips 1 and two drive substrates 3 for controlling these semiconductor image sensor chips 1 to take out signals are integrated by a reinforcing member 28, and are electrically connected. Specifically, the semiconductor image sensor chip 1 and the semiconductor image sensor chip 1 and the drive substrate 3 and the corresponding electrodes on the semiconductor drive chip 2 and the drive substrate 3 are connected by wires 25, which are not shown. A structure is known that takes

The drawing shown in FIG. 13 is simplified for easy understanding. In practice, the semiconductor image sensor chip 1 has a sense line direction of 5 cm to 7 cm.
It is a semiconductor that is significantly larger than a general semiconductor with a size of about 3 cm in the right angle direction of about 300 cm.
The structure is such that the number of sense lines 5 of the standard number (only six sense lines 5 are drawn in FIG. 13) are arranged regularly at a pitch of about 50 microns. Therefore, the entire device illustrated in FIG. 13 has a length of about 30 cm and a width of about 3 cm.

[0004]

As described above, in the conventional multi-chip mounting type semiconductor image sensor device, a plurality of chips or circuit boards are mechanically fixed to be an integrated one, and electrically. Since connecting them into one system was performed by different means, there were the following problems.

The structure is based on the existence of a mechanical support mechanism. The mechanical support structure portion affects the light receiving surface area and adversely affects the detection capability. Both mechanical fixing and electrical connection work are required, resulting in a long processing time.

[0006] Electrical connection by wires cannot be performed well if the pitch between electrodes for wire bonding is too narrow. (At the time of wire bond work, there is a concern that the wire may be cut by touching the adjacent wiring that has already been connected.) Even if the wire bond work is completed successfully, if an external force such as touching the wire is applied, There is a concern that the wires may break or the wires next to each other may come into contact and cause a short circuit.

Since the mechanical rigidity is provided only by the mechanical support mechanism, there are many restrictions on the shape and arrangement of the support member. Therefore, an object of the present invention is, in order to solve such a conventional problem, not to affect the light-receiving surface area, while the mechanical fixing structure also has a function of electrical connection. It is simple, has sufficient mechanical rigidity, and has stable electrical connection even in a narrow-pitch sense line, and has excellent electrical characteristics. Once the electrical connection is made, the connection quality is stable. It is to obtain a multi-chip mounting type semiconductor image sensor device as described above.

[0008]

In order to solve the problem of the conventional example shown in FIG. 13, in the improvement example shown in FIG. 1, in a multi-chip mounting type semiconductor image sensor device, a space between adjacent semiconductor image sensor chips is increased. And a component having a wiring pattern for electrical connection and an electrode terminal for electrical connection on a solid surface, such as a silicon chip or a glass chip, for connecting the adjacent semiconductor image sensor chip and the drive substrate to each other. Mounting is performed with the surface having the wiring and the electrode terminal facing the electrode terminal of the semiconductor image sensor chip (hereinafter abbreviated as face-down mounting).
It was configured like this.

[0009]

In the multi-chip mounting type semiconductor image sensor device configured as described above, the following actions are obtained. Since the mechanical support mechanism is not required, the mechanical support structure portion does not affect the light receiving surface area and adversely affect the detection.

The work of mechanical fixing and electrical connection can be performed at the same time, and the connection can be performed collectively between the adjacent semiconductor image sensor chips or between the semiconductor image sensor chip and the driving substrate, so that the processing time can be shortened. Since the wiring formed on the connection chip is formed on the surface by a semiconductor process or the like, the wiring will not be broken or come into contact during and after the connection. In addition, since the wiring density can be increased, it is possible to connect at a narrower pitch. Consequently, the sense lines in the light receiving surface area of the semiconductor image sensor chip can be made higher in density, and the detection capability (resolution of position coordinates to be detected) can be improved. it can.

After the connection, the wiring and electrode terminal of the connection chip and the electrode terminal of the other side are in a state of being sandwiched between the chips, so that the connection site is not directly exposed to the outside and the connection quality can be kept high, that is, reliability. You can improve the property.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a top view showing a basic configuration of an embodiment of a semiconductor image sensor device according to the present invention. The four semiconductor image sensor chips 1 are aligned in an accurate positional relationship, and the semiconductor chips are mechanically fixed and electrically connected to each other by using the connection chip 4. On both sides, there are laid out two drive substrates 3 on which semiconductor drive chips 2 for controlling these four sensor chips and extracting information are mounted facedown, and these are also connection chips 4 for the semiconductor image sensor. The chip 1 is mechanically fixed and electrically connected.

A semiconductor image sensor chip 1, which is a main component of this semiconductor image sensor device, has connection electrode terminals (not shown) on both front and back surfaces of the connection portion at both ends in the left-right direction of FIG. Is an image sensor on both sides. Further, FIG. 12 is a plan view showing in detail a drive substrate 3a made of single crystal silicon as an example of the drive substrate 3 in the embodiment shown in FIG. The drive substrate 3a made of single-crystal silicon is a double-sided substrate made of a silicon substrate, and the electrode terminals of the semiconductor drive chip 2 are electrically connected to the semiconductor drive chip electrode terminals 18 made of gold bumps or the like. Two front and back surfaces are mounted so that they face each other (face down). The semiconductor driving chip 2 drives the semiconductor image sensor chip 1 and processes signals obtained from the semiconductor image sensor chip 1 to transmit information from the sensor chip to a system (not shown) external to the semiconductor image sensor device. Has the function of transmitting. An external connection electrode terminal 19 is provided on the drive substrate 3a made of single crystal silicon for exchanging signals with the external system. Also,
The drive substrate 3a made of single crystal silicon has sense line electrode terminals 16 for electrical connection with the semiconductor image sensor chip 1 on both the front and back sides of the side adjacent to the semiconductor image sensor chip 1. Further, since the single crystal silicon drive substrate 3a is made of the same silicon substrate as the semiconductor image sensor chip 1, the connection chip 4, the semiconductor drive chip 2, etc., even if the temperature rises during mounting, any component Also has the same coefficient of thermal expansion, and there is no problem of deterioration in mechanical position accuracy due to the difference in coefficient of thermal expansion.

Next, the mechanical and electrical connection between the semiconductor image sensor chips 1 and between the semiconductor image sensor chip 1 and the drive substrate 3 will be described. 2 is an enlarged top view showing a connection portion between adjacent semiconductor image sensor chips 1 in the embodiment shown in FIG. 1 according to the present invention, and FIG. 3 is an enlarged side view thereof. Also, FIG.
FIG. 4 is a perspective view showing a single crystal silicon connection chip 7 as an example of the connection chip 4 shown in these drawings.

The states shown in FIGS. 2 and 3 show a state in which the semiconductor image sensor chip 1 and the connection chip 4 are electrically connected so that their electrode terminal portions are overlapped with each other. Sense lines 5 as shown in FIG. 2 are formed at regular intervals on both front and back surfaces of the semiconductor image sensor chip 1. Electrode terminals 6 made of gold bumps or the like for electrical connection to the outside are provided at both ends of the chip of each sense line 5. (Not shown in FIG. 2. Only 11 sense lines 5 are drawn in FIG. 2, but this is for the sake of clarity of the drawing.
As in the conventional example, there are about 600 sense lines 5 at a pitch. ) Furthermore, as shown in FIG. 4, the connection chip 7 made of single crystal silicon, which is an example of the connection chip 4, has wiring 9 and electrodes at the same pitch as the semiconductor image sensor chip 1 on the surface facing the semiconductor image sensor chip 1. There is a terminal 8. The electrode terminal 8 is composed of a gold bump or the like for electrical connection with the electrode terminal 6 of the semiconductor image sensor chip 1 facing the electrode terminal 8.

FIG. 5 shows a connecting chip 7 made of single crystal silicon.
FIG. 7 is a diagram for explaining how to mount the device by accurately aligning it with the electrode terminal 6 of the semiconductor image sensor chip 1. That is, when the connecting chip 7 made of single crystal silicon is placed on the electrode terminal 6 of the semiconductor image sensor chip 1, the electrodes to be connected are hidden and invisible. Therefore, in the present embodiment, the X-direction alignment line 10a and the Y-direction alignment line 10b are provided on the back surface of the single crystal silicon connection chip 7 (the surface that does not contribute to the connection, that is, the upper surface in FIG. 5). Regarding the direction, the X-direction alignment line 10a and the X-direction alignment mark 11 on the semiconductor image sensor chip 1 are aligned so as to form a straight line, and regarding the Y-direction, the Y-direction alignment line 10b and the semiconductor image sensor chip 1 correspond. By aligning the sense lines 5 so as to form a straight line, the hidden and invisible electrode terminals can be aligned with each other. After alignment, the two semiconductor image sensor chips 1 are mechanically and electrically coupled by the method described in detail below.
Electrically integrated.

Next, a method for establishing electrical connection and mechanically fixing the two will be described. FIG. 6 shows a state in which the semiconductor image sensor chips 1 and 2 according to the embodiment of the present invention are electrically connected and mechanically fixed via the connection chip 4 by the adhesive force of the insulating adhesive 12. It is sectional drawing which expands and shows only a vicinity. This insulating adhesive 1
Due to the shrinkage force of the second curing, both electrode terminals (electrode terminal 6
A pressing force is applied between the electrode and the electrode terminal 8) to establish electrical continuity. Needless to say, the curing method may be a method suitable for each adhesive, such as UV irradiation for a photo-curing adhesive or a heat curing for a heat-curing adhesive, depending on the type of adhesive.

In this embodiment, the electrode terminals 6 and 8 are drawn on the assumption that they are made of gold bumps, but if at least one of them is made of gold bumps, the other electrode terminal may be an aluminum pad. . FIGS. 7 and 8 show that the cutting portion of the embodiment described in FIG. 6 is rotated 90 degrees,
That is, it is a partially enlarged sectional view in which only two electrode terminals cut in the width direction of the connection chip 4 and the semiconductor image sensor chip 1 are enlarged. 7 and 8 show a connection chip 4 in which the upper electrode terminals 8a, 8b, 8c, 8d are made of gold bumps, and the lower electrode terminal 6a is a semiconductor image sensor chip 1 which is an aluminum pad. By the way, it is inevitable that the bump height of the gold bump has a variation of about ± 10% of the target value of the height even if the manufacturing process is strictly controlled. For example, when the target bump height value is 10 μm, it is necessary to allow a bump height variation of about ± 1 μm (seeing each bump height,
It is necessary to allow variations in the width of 9 μm to 11 μm. ).

In both of the examples shown in FIGS. 7 and 8, the left gold bump electrode terminal 8a and the surface bumpy gold bump electrode terminal 8c are the right gold bump electrode terminal 8b and the surface bumpy gold bump. The case where the height is slightly higher than that of the electrode terminal 8d before mounting is shown. Therefore, in FIG. 7, the connection between the electrode terminals on the right side is not made, whereas in FIG. 8, the electrical connection between the electrode terminals is normally made on the left and right sides. The reason for this difference is that if there are fine irregularities on the surface of the gold bump as shown in FIG. 8, even if a small force is applied, the convex portions of the fine irregularities on the surface can be deformed and connection can be made, while as shown in FIG. If the surface of the gold bump is too smooth, the entire bump cannot be compressed by the required amount only by the compressive force obtained by mounting such as the contracting force when the insulating adhesive 12 is cured, so that a gap remains between the right electrode terminals. It shows the state of being lost.

Here, in this embodiment, the connection chip 4 is temporarily assumed.
If the electrode terminals 8a, 8b, 8c, 8d on the side are not made of gold bumps but aluminum pads, the insulating protective film 13 shown in FIGS. 7 and 8 (the surface of the semiconductor element surface such as a passivation film or a silicon nitride film) is formed. (For protecting the environment from humidity and the like) is slightly higher than the aluminum pad, the insulating protective films of the electrode chip of the connection chip 4 and the semiconductor image sensor chip 1 collide with each other. However, contact cannot be obtained between the two aluminum pads. Therefore, either one of the electrode terminals needs to have a structure in which the conductor portion is higher than the insulating protective film such as a gold bump.

In this way, electrical conduction and mechanical coupling of the semiconductor image sensor device are performed simultaneously. Also,
Considering only electrical conduction, unlike the wire bond method, all the electrode terminals are connected at once, so not only is the man-hour drastically reduced, but also after the connection, Since the electrode terminal and the wiring are hidden under the connection chip 4 and protected from the external environment, the reliability of the electrical connection quality is improved.

In this embodiment, the double-sided integrated circuit whose both sides are composed of sensing elements has been described. However, in the case of a general element in which only one side is an integrated circuit,
It is also possible to employ a method in which the surface not formed as an integrated circuit is positioned and connected by a connection chip having no electrical function, and then the surface on the integrated circuit side is electrically connected.

Next, an example of a method of connecting the connection chip 4 when the insulating adhesive 12 is used will be described with reference to the drawings. FIG. 9 shows a state in which a film-like insulating adhesive sheet 15, which is a kind of insulating adhesive, is temporarily pressure-bonded onto the electrodes of the connection chip 7 made of single crystal silicon of the embodiment of the semiconductor image sensor device according to the present invention. It is a perspective view. (In FIG. 9, the single crystal silicon connection chip 7 has been described as an example, but it goes without saying that the same applies when a glass connection chip or the like is used as the connection chip 4.) The electrode 8 on the side where the wiring 9 is provided in advance. The insulative adhesive sheet 15 is formed into an appropriate shape on the upper side, and is slightly pressured and heated to temporarily press-bond it. FIG. 10 is a perspective view showing a state in which the insulating adhesive sheet 15 is temporarily pressure-bonded to the connection portion of the semiconductor image sensor chip 1 in the same manner as in FIG. In this way, the supply of the insulating adhesive sheet 15 as the preparatory work for connection is performed on either one of the single crystal connection chip 7 side, the semiconductor image sensor chip 1 and the drive substrate 3 side, or both.

FIG. 11 is a perspective view when two semiconductor image sensor chips 1 of the embodiment of the semiconductor image sensor device according to the present invention are thermocompression-bonded with a connecting chip 7 made of single crystal silicon using an insulating adhesive sheet 15. Is. The two semiconductor image sensor chips 1 and the connecting chip 7 made of single crystal silicon are in a positional relationship such that the positions of the electrode terminals are aligned with each other. The insulating adhesive sheet 15 is interposed between the opposing electrode terminals. Here, the heated thermocompression bonding head 20 descends to the connection portion and applies pressure, whereby electrical connection and mechanical connection between the two semiconductor image sensor chips 1 are achieved. The same applies to the connection between the semiconductor image sensor chip 1 and the drive substrate 3 and the connection on the back surface. By using the insulating adhesive sheet 15 for connection, the temperature at the time of connection can be made much lower than when the gold-gold eutectic bonding method is used. (At the time of gold-gold eutectic bond 400-
(500 ° C, 200 ° C or less when crimping the insulating adhesive sheet) Therefore, workability and safety in the connection process are improved,
Further, it is possible to prevent deterioration of the quality of each component of the semiconductor image sensor device.

The present invention has described the details of the structure of an electronic device which exhibits a function by combining a plurality of semiconductor chips by taking a semiconductor image sensor device as an example. However, this structure requires high-density mounting. It goes without saying that it can be used for various electronic devices.

[0026]

As described above, according to the present invention, in the case of the semiconductor image sensor device taken as an example this time,
High-performance multi-chip mounting type semiconductor image sensor device that achieves electrical conductivity and mechanical strength at the same time by using a connection chip to connect the semiconductor image sensor chip and the drive substrate, and has both strength and reliability with a simple structure. Is obtained.

[Brief description of drawings]

FIG. 1 is a top view of an embodiment of a semiconductor image sensor device according to the present invention.

FIG. 2 is an enlarged top view of a connecting portion of the embodiment of the semiconductor image sensor device according to the present invention.

FIG. 3 is an enlarged side view of a connecting portion of the embodiment of the semiconductor image sensor device according to the present invention.

FIG. 4 is a lower perspective view of a connection chip made of a single crystal silicon plate of an embodiment of a semiconductor image sensor device according to the present invention.

FIG. 5 is a perspective view showing a state in which the connection chips of the single crystal silicon plate of the embodiment of the semiconductor image sensor device according to the present invention are aligned.

FIG. 6 is a partially enlarged view of a connecting portion showing a state in which both sides of the semiconductor image sensor chip are connected with an insulating adhesive via the connection chip of the embodiment of the semiconductor image sensor device according to the present invention.

FIG. 7 is a partially enlarged view of a connecting portion showing a state in which the connecting chip and the semiconductor image sensor chip are connected by an insulating adhesive when the electrode terminal heights are not uniform in the embodiment of the semiconductor image sensor device according to the present invention. .

8 is a diagram showing an example different from the example shown in FIG. 7 only in that the surface condition of the electrode terminals has fine irregularities.

FIG. 9 is a perspective view showing a state in which an insulating adhesive sheet is temporarily pressure-bonded to the surfaces of the connection chip and the electrode terminal of the embodiment of the semiconductor image sensor device according to the present invention.

FIG. 10 is a perspective view showing a state in which an insulating adhesive sheet is temporarily pressure-bonded to the surfaces of the electrode terminal portions of two adjacent semiconductor image sensor chips in the embodiment of the semiconductor image sensor device according to the present invention.

FIG. 11 is a perspective view showing a state in which two adjacent semiconductor image sensor chips of the embodiment of the semiconductor image sensor device according to the present invention are thermocompression bonded with a connecting chip using an insulating adhesive sheet.

FIG. 12 is a plan view of a drive substrate made of a single crystal silicon plate of a semiconductor image sensor device according to an embodiment of the present invention.

FIG. 13 is a perspective view showing an example of a conventional semiconductor image sensor device.

FIG. 14 is a perspective view of the conventional example shown in FIG. 13 seen from below.

[Explanation of symbols]

 1 Semiconductor Image Sensor Chip 2 Semiconductor Driving Chip 3 Driving Substrate 3a Single Crystal Silicon Driving Substrate 4 Connection Chip 5 Sense Line 6 Electrode 6a Aluminum Pad 7 Single Crystal Silicon Connection Chip 8 Electrode Terminal 8a Gold Bump Electrode Terminal 8b Gold Bump Electrode terminal 8c Gold bump electrode electrode terminal with surface irregularities 8d Gold bump electrode electrode terminal with surface irregularities 9 Wiring 10a X-direction alignment line 10b Y-direction alignment line 11 X-direction alignment mark 12 Insulating adhesive 13 Insulating protective film 15 Insulating adhesive sheet 16 Sense line electrode terminal 17a Wiring 17b Wiring 18 Semiconductor driving chip electrode terminal 19 External connection electrode terminal 20 Thermocompression bonding head 25 Wire 26 Board side wire electrode 27 Sensor side wire electrode 28 Reinforcement material

Claims (4)

[Claims] 1. A plurality of semiconductor chips, a semiconductor drive chip for driving the semiconductor chips, a drive substrate on which the semiconductor drive chips are mounted, and which electrically and mechanically connects the semiconductor drive chips, In an electronic device comprising a connection chip for mechanically and electrically connecting between semiconductor chips or between the semiconductor chip and the drive substrate on which the semiconductor drive chip is mounted, the semiconductor drive chip and the drive substrate or An electronic device comprising an electrically insulating adhesive between the semiconductor chip and the connection chip or between the drive substrate and the connection chip. 2. The electronic device according to claim 1, wherein the electrically insulating adhesive is an epoxy resin adhesive for double-sided tape. 3. At least one electrode terminal selected from the semiconductor chip, the electrode terminal of the connection chip, the electrode terminal of the semiconductor drive chip, the drive substrate, and the electrode terminal of the drive substrate and the connection chip is a gold bump. The electronic device according to claim 1, wherein: 4. The electronic device according to claim 3, wherein the gold bumps have irregularities with a height difference of 2 μm or less on the surface.