JPH085566Y2 - Solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a solid-state image pickup device in which a semiconductor chip provided with a photoelectric conversion circuit is face-bonded to a mounting member.

[Prior Art] In recent years, solid-state imaging devices (or devices) (hereinafter abbreviated as SID) such as charge-coupled devices (hereinafter abbreviated as CCD) have come to be widely used for various imaging means.

For example, in Japanese Utility Model No. 63-49512, the SID is attached to the tip of the endoscope.
Is housed to form an image pickup means. In this case, the incident light is incident on the front surface (front surface) side of the SID and is imaged on the imaging surface. It is converted into an image signal by this SID and output from the input / output terminal provided on the back surface or the side surface.

When the SID is incorporated into the endoscope tip as in this conventional example, in order to make the endoscope tip thin, it is necessary to minimize the cross-sectional shape of the SID in the direction orthogonal to the optical axis.

As a conventional example of the SID incorporated in the endoscope tip portion or the like, a semiconductor chip is die-bonded to a mounting substrate such as a ceramic substrate or a lead frame as shown in, for example, Shokai Sho 64-21580 and provided on the surface of the semiconductor chip. The bonding pad and the mounting board are electrically connected by wire bonding.

[Problems to be solved by the invention] In a SID having a structure such as the actual development Sho 21-21580, the mounting board is extended around the bonding pad for electrical connection by wire bonding. , SID is at least the length of the wire for wire bonding
However, there is a drawback that the area shape is increased.

For this reason, the tip of the endoscope in which this SID is incorporated also becomes thick.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a solid-state image pickup device capable of downsizing the image pickup means without thickening the distal end portion of the endoscope.

[Means and Actions for Solving Problems] In the present invention, a semiconductor chip having a photoelectric conversion circuit on the front surface and a circuit pattern on the back surface is face-bonded to a mounting member such as a substrate having bumps on the front surface. As a result, the semiconductor chip can be mounted without requiring wire bonding, and the size can be reduced.

[Embodiment] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 7 relate to a first embodiment of the present invention, and FIG. 1 is a sectional view showing the structure of a solid-state image pickup device of the first embodiment.
FIG. 2 is an explanatory view showing the manufacturing process of the semiconductor chip, FIG. 3 is a plan view of the semiconductor chip, FIG. 4 is a bottom view of the semiconductor chip, FIG. 5 is a sectional view of a mounting board, and FIG. 6 is a mounting board. And FIG. 7 is a bottom view of the mounting board.

SID (solid-state imaging device) 1 of the first embodiment shown in FIG.
Is a semiconductor chip 4 (shown in FIG. 2E) having a photoelectric conversion circuit 2 on the front surface and a mounting circuit pattern 3 on the back surface, and the circuit pattern 3 of the semiconductor chip 4. It is composed of a mounting substrate 7 on the surface of which a printed circuit 6 electrically connected by the bump 5 is formed, and a transparent sealing resin 8 for sealing the periphery of the semiconductor chip 4 mounted on the mounting substrate 7. It

The photoelectric conversion circuit 2 formed on the surface of the semiconductor chip 4 is electrically connected to the through hole 10 by the wiring material 9, and is electrically connected to the circuit pattern 3 on the back surface through the through hole 10. The circuit pattern 3 is electrically connected to the printed circuit 6 on the surface of the mounting substrate 7 by the bump 5.
The printed circuit 6 is electrically connected to the printed circuit 12 on the rear surface of the mounting substrate 7 through the through hole 11. This printed circuit
An external lead 13 is fixed to 12 and a drive signal is applied to several of the external leads 13 so that an image signal obtained by photoelectric conversion can be output from the external lead 13 serving as an output terminal.

By the way, the semiconductor chip 4 can be manufactured by a manufacturing process as shown in FIG. 2, for example.

As shown in FIG. 2 (a), a single crystal silicon wafer 14
A circuit pattern 3 is formed on the back surface of the substrate by a thick film technique. In this case, the circuit pattern 3 having a thick film may be used instead of the circuit pattern 3 having a thick film. Alternatively, a metal plate such as gold or copper may be attached to the back surface and the circuit pattern 3 may be formed by etching. Further, the circuit pattern 3 is described, but it may be a simple pattern. The point is that the through hole 10 and the bump 5 can be connected.

Next, as shown in FIG. 2B, a photoelectric conversion circuit (imaging circuit) 2 such as a CCD is formed on the surface of the silicon wafer 14 by a thin film technique.

Next, as shown in FIG. 2 (c), the silicon wafer 14
Etching is repeated on the surface portion of the back surface corresponding to the circuit pattern 3 to form a through hole 10 penetrating from the front surface to the back surface. In this case, the circuit pattern 3 is made of a material that is not attacked by the etching agent when the silicon wafer 14 is etched. Therefore, the circuit pattern 3 is exposed at the opening on the back surface side of the through hole 10. If the through hole 10 is substantially tapered as shown in the drawing, it is easy to etch.

The position on the front surface side where this etching is performed corresponds to the position of the conventional bonding pad for wire bonding, and is provided at an appropriate position. The photoelectric conversion circuit 2
It is easy to make because it can be made by semiconductor process before and after making.

Next, as shown in FIG. 2D, the photoelectric conversion circuit 2 and the circuit pattern 3 on the back surface are electrically connected by the wiring material 9 on the front surface side and the wiring material of the through hole 10 by Al wiring or the like. In this case, if the through hole 10 is tapered, Al can easily enter deep inside the through hole 10 and the reliability of connection can be improved.

The Al wiring can be formed by Al vapor deposition, but is not limited to this vapor deposition method. In short, through holes
The photoelectric conversion circuit 2 and the circuit pattern 3 on the back surface side may be electrically connected via 10

Next, by performing scribing for cutting into a predetermined shape, the semiconductor chip 4 shown in FIG. 2 (e) can be manufactured.

When the semiconductor chip 4 of FIG. 2 (e) is viewed from above the front surface, it becomes as shown in FIG.
It becomes like the figure.

Incidentally, in FIG. 3, the wiring member 9 on the front side is not shown,
The dotted line shows the shape of the front side opening of the through hole 10. Further, in FIG. 4, the shape of the back side opening of the through hole 10 located in the central portion of the circuit pattern 3 is shown by a dotted line. Further, in FIG. 4, one pattern of the circuit pattern 3 is made into a solid earth in order to give a reference potential to the photoelectric conversion circuit 2 (it is not necessary to make it into a solid earth). Next, referring to FIG. explain.

This mounting board 7 is, for example, an ordinary ceramic base 15.
The board body is made of. This ceramic base
A printed circuit 6 is formed on the surface of 15 by printed wiring, and this printed circuit 6 is electrically connected to the printed circuit 12 on the back surface side through a through hole 11. External leads 13 are brazed and fixed to the printed circuit 12.

Bumps 5 are provided on the printed circuit 6 on the surface by gold or solder. Since the bumps 5 are provided not on the semiconductor chip 4 but on the mounting substrate 7 side, the back surface of the semiconductor chip 4 can be flattened and the semiconductor chip 4 can be easily manufactured.

The printed circuits 6 and 12 can be formed by thick film printing, for example.

The mounting board 7 is as shown in FIG. 6 when viewed from the front side, and as shown in FIG. 7 when viewed from the back side.

As shown in FIG. 6, by changing the pattern shape of the printed circuit 6, the order of the external lead 13 connected on the back side via the printed circuit 6 and the through hole 11 can be changed. . Of course, the position on the external lead 13 side can also be provided at an appropriate position.

Therefore, the degree of freedom of artwork of the circuit board connected to the SID1 is increased, and the SID1 can be downsized.

The semiconductor chip 4 is face-bonded to the mounting substrate 7, that is, the bumps 5 on the front surface of the mounting substrate 7 and the circuit pattern 3 on the back surface of the semiconductor chip 4 are connected and sealed with the transparent sealing resin 8. SID1 with the structure shown in Fig. 1 will be assembled.

According to the first embodiment, it is possible to electrically connect to the back surface side of the semiconductor chip 4 without using a bonding wire, and the circuit pattern 3 on the back surface side is face-bonded to the bumps 5 to form a printed circuit on the mounting substrate 7. 6, the printed circuit 6 is electrically connected to the external lead 13 fixed to the printed circuit 12 on the back surface side through the through hole 11, so that the SID 1 can be miniaturized.

When the through hole 10 is provided, if the circuit pattern 3 is not provided on the back surface side, the silicon wafer 14 provided with the photoelectric conversion circuit 2 is provided.
Must be turned over and the circuit pattern 3 must be provided. At this time, the photoelectric conversion circuit 2 is easily scratched. However, in the first embodiment, the circuit pattern 3 is provided before the photoelectric conversion circuit 2 is provided. I can prevent it.

The pattern width of the circuit pattern 3 is the photoelectric conversion circuit 2
Since the pattern width is much rougher than the pattern width of, the through hole 10 and the circuit pattern 3 do not actually deviate even if the silicon wafer 14 is turned over after the circuit pattern 3 is provided.

Further, after FIG. 2B, the semiconductor chip-4 can be manufactured by using almost the same manufacturing process and technique as those for manufacturing a normal semiconductor. However, the difference is that when the through hole 10 is formed, etching is performed for a long time.

Also, as shown in FIG. 2 (d), when Al vapor deposition is performed, Al
It is preferable to make the through hole 10 relatively large or to have a tapered shape so as to have a good adhesion. Still, it can be much smaller than the wire-bonding structure.

Also, the thinner the silicon wafer 14, the better
It becomes easy to provide the wiring member 9.

FIG. 8 shows SID21 of the second embodiment of the present invention. In the second embodiment, the translucent adhesive 22 is applied to the surface of the semiconductor chip 4 '.
The color filter 23 is fixed via. In the wire bonding type structure, the color filter 23 cannot be adhered unless the space between the photoelectric conversion circuit 2 and the bonding pad is widened, whereas this is not necessary in the second embodiment. That is, the photoelectric conversion circuit 2 is electrically connected to the circuit pattern 3 on the back side by the wiring material 9, the height of the wiring material 9 can be ignored, and the color filter 23 can be fixed by adhesion so as to cover the wiring material 9. . Therefore, the color filter 23 can be downsized both in the height (thickness) direction and the area.

In this embodiment, the through hole 10 'of the semiconductor chip 4'is
Has a non-tapered shape.

Further, in this embodiment, the mounting substrate 24 has the external leads 13 fixed to the surface side of the substrate body, and the bumps 5 are provided on the external leads 13. Then, the bumps 5 are connected to the circuit pattern 3 on the back surface of the semiconductor chip 4'by face bonding and sealed with the light-shielding sealing resin 25.

The sealing with the sealing resin 25 is performed by the semiconductor chip 4 '.
After the color filter 23 is bonded with the translucent adhesive 22, it is performed.

The through hole 10 'may be a tapered through hole 10.

The second embodiment has the same effects as the first embodiment, and the mounting board 24 can be manufactured more easily.

FIG. 9 shows SID31 of the third embodiment of the present invention. In this embodiment, as in the second embodiment, a color filter 23 is adhered to the semiconductor chip 4'with a translucent sealing resin 22.

On the other hand, the back surface of the semiconductor chip 4'is faced down with respect to the lead frame having the bumps 5 formed thereon.
The SID 31 having the structure shown in FIG. 9 can be manufactured by bonding, molding with the light-shielding encapsulating resin 25, and then cutting the outer lead 13 portion of the lead frame to separate the outer leads 13 and bending them. It may be projected laterally without being bent.

The third embodiment has the same effects as the first embodiment and does not require a mounting board, so that the cost can be further reduced.

Although each of the above-described embodiments has a structure having the external lead 13 with a lead, it may be a leadless input / output terminal.

Also, other package structures can be used,
Different assembly procedures can be used.

Note that, for example, in the first embodiment, the tapered through hole 10 may have a structure in which the opening on the back surface side is large. In this case, for example, the circuit pattern 3 may have a shape having an opening.

Further, for example, in the first embodiment, after the through hole 10 as shown in FIG. 2 (c) is provided, the through hole 10 may be completely filled with the wiring material as shown in FIG. 2 (d). Alternatively, only the portion on the photoelectric conversion circuit 2 side may be formed and cut into a straight line connecting the central portions of the through holes 10. By doing so, the size can be further reduced. In this case, it is desirable that the wiring material 9 on the surface is formed so as not to be outside the cut portion. Further, it is desirable that the circuit pattern 3 on the back surface is also formed so as not to go out of the cut surface (to prevent the wiring material 9 or a part of the circuit pattern 3 from being peeled off when cut).

A gallium arsenide wafer may be used instead of the silicon wafer.

Further, the photoelectric conversion circuit 2 may have a structure in which a lens is integrated.

[Advantages of the Invention] As described above, according to the present invention, a semiconductor chip having a photoelectric conversion circuit on the front surface and a circuit pattern on the back surface is face-bonded to a mounting member such as a mounting substrate having bumps on the front surface. Since it has a structure mounted as described above, it is possible to realize a smaller solid-state imaging device than wire bonding.

[Brief description of drawings]

1 to 7 relate to a first embodiment of the present invention.
FIG. 3 is a sectional view showing the structure of the solid-state image pickup device of the first embodiment, FIG.
FIG. 4 is a plan view of a semiconductor chip, FIG. 4 is a bottom view of a semiconductor chip, FIG. 5 is a sectional view of a mounting board, FIG. 6 is a plan view of a mounting board, FIG. 7 is a bottom view of a mounting board, and FIG. FIG. 9 is a sectional view showing the structure of the second embodiment of the present invention, and FIG.
It is sectional drawing which shows the structure of an Example. 1 ... Solid-state imaging device, 2 ... Photoelectric conversion circuit, 3 ... Circuit pattern, 4 ... Semiconductor chip, 5 ... Bump, 6,12 ... Printed circuit, 7 ... Mounting board, 10, 11 ... Through hole, 13 ... … External leads

Claims (1)

[Scope of utility model registration request] 1. A semiconductor substrate having photoelectric conversion circuit means on the front surface thereof and mounting means provided on the back surface thereof apart from the side wall, and the side wall between the photoelectric conversion circuit means and the side wall of the semiconductor substrate. Connecting means for connecting the photoelectric conversion circuit means and the mounting means in the thickness direction, and a mounting means having a semiconductor mounting surface on the front surface and an input / output terminal on the back surface or the side surface side. A solid-state image pickup device, wherein the mounting means of the semiconductor substrate is mounted on the semiconductor mounting surface of the mounting means by face bonding.