JPH0813107B2 - Solid-state imaging device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solid-state imaging device, and particularly to a small-sized solid-state imaging device.

[Conventional technology]

Conventionally, as a solid-state image pickup device, there is one proposed, for example, in JP-A-60-62279. In this solid-state image pickup device, a solid-state image pickup element chip is fixed on an outer enclosure such as ceramic, and an opening of the outer enclosure is provided with a transparent flat plate (cover glass).
Then, a transparent resin is filled between the chip and the cover glass.

[Problems to be solved by the invention]

However, when the solid-state imaging device of JP-A-60-62279 is incorporated into an endoscope or the like, it is possible to fix the cover glass by making the incident surface of the cover glass abut against the frame of the objective optical system. In this case, the parallelism between the cover glass entrance surface and the chip entrance surface (imaging surface) becomes a problem. This parallelism is affected not only by the wedge-shaped change in the thickness of the cover glass, but also by the variation in the thickness and flatness of the thickness of the outer structure, the external lead-out wire, and the variation in the bonding thickness of the joints of these parts. . If this parallelism deteriorates, the chip image pickup surface is not perpendicular to the optical axis of the objective lens and tilts, resulting in partial blurring. Further, it is desired that the solid-state image pickup device incorporated in the distal end portion of the endoscope be ultra-small, but the entire device becomes large due to the outer enclosure structure.

Further, a structure shown in FIG. 6 is conceivable as a solid-state image pickup device incorporated in the distal end portion of the endoscope. In this solid-state image pickup device 1, a solid-state image pickup element chip 3 is fixed on a flat plate-shaped base 2 made of ceramic or the like, a cover glass 4 is directly provided on an image area of the chip 3, and a lead leg 5 is implanted in the base 2.
The bonding wire is connected between the chip bonding pad and the chip side bonding pad to form a bonding portion on the side of the cover glass 4. The chip 3, the lead leg 5, the wire 6 and the like of this bonding portion are filled and sealed with a sealing material 7 such as resin, and the upper surface thereof is formed to be flush with the upper surface of the cover glass. In this case, since the upper surface of the solid-state imaging device 1 is composed of two members, the cover glass 4 and the resin sealing material 7, the flatness is poor, and the resin may cause a sink mark 8 due to shrinkage during molding. When such a solid-state imaging device 1 is attached to the frame body 9 of the objective optical system, one-sided blur occurs due to the inclination of the imaging surface.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems by increasing the size of the entire device, and an object of the present invention is to provide a solid-state imaging device having a miniaturized package.

[Means for solving problems]

According to the present invention, a solid-state image sensor chip having an outer shape of the same shape as the base member having an image area and a bonding pad is stacked on a surface of a base member having a conductive portion on the back surface or the side surface, The bonding pad of the image pickup device and the conductive portion of the base member are connected by a bonding wire, the conductive portion, the bonding pad and the bonding wire are sealed with a sealing material, and the solid-state image pickup device is provided on the back side of the base member. It is a solid-state imaging device in which an input / output terminal is provided in the outer shape of a chip.

[Action]

In the solid-state imaging device of the present invention, a conductive portion of a base member is formed on a back surface or a side surface, a solid-state imaging element chip having the same outer shape as the base member is superposed on the base member, and a bonding pad on the surface of the chip. And a conductive part of the base member are connected by a bonding wire, the conductive part, the bonding pad, and the bonding wire are sealed with a sealing material, and the back side of the base member is inserted into the outline of the solid-state imaging device chip. By providing the output terminal, since the bonding wire is extremely thin, the entire size can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a distal end portion of an endoscope incorporating a solid-state imaging device, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. The tip portion 11 of the insertion portion of the endoscope 10 has a tip component body 12,
A first mounting hole 13 and a second mounting hole 14 are formed in the hole 12. The first mounting hole 13 is formed eccentrically with respect to the central axis of the tip component body 12. Into the first mounting hole 13, a cover glass lens 15 and a lens frame 17 with an aperture stop having a partial lens system 16 of an objective lens held therein are inserted and fixed. Further, a partial lens 18 of the objective lens is also inserted from the rear of the mounting hole 13. A solid-state image pickup device frame 21 to which a solid-state image pickup device 20 and the like are fixed is inserted and fixed in a mounting hole 13 behind the lens 18. In this fixed image pickup device 20, a solid-state image pickup element chip 23 is fixed on a base 22 made of epoxy resin mixed with ceramic or glass fiber. An image area 24 having a predetermined area and a chip side bonding pad 25 are formed on the chip 23. On the other hand, the lead legs 26 penetrate the base 22 and project to both sides on the base 22, and the fixing side of the chip 23 is formed at substantially the same height as the upper surface of the chip 23. The bonding pad 25 and the lead leg 26 are connected by a bonding wire 27. Also,
A first cover glass 28 is bonded on the image area 24, and a second cover glass 29 is bonded on the first cover glass 28 so as to cover the bonding portion formed by the bonding wire 27. . In the first embodiment, the inside of the solid-state imaging device frame 21 is formed in a circular shape, so the base 22 and the second cover glass 29 are formed in a circular shape having a diameter slightly smaller than the inner diameter of the frame 21. This second cover glass
A circular flare stop 30 is formed around the tip 23 side of 29. It is preferable that the flare diaphragm 30 should be observed uniformly in the vertical and horizontal directions with an endoscope. It is provided so that it does not hit other than 31. The flare stop 30 is formed by roughening a blackened portion around the emission surface side of the second cover glass 29 by photo-corrosion and then inking the portion. Further, in the solid-state imaging device 20, the bonding portion between the base 22 and the second cover glass 29 is filled with the sealing resin 32.

The circuit board 33 connects and fixes the lead legs 26 of the solid-state imaging device 20 to the back surface of the base 22 of the solid-state imaging device 20 thus configured by soldering or the like. An electronic component 34 such as an IC is also mounted on this substrate 33. In FIG. 1, the chip-on-board method is used. A signal line 35 is also connected to the substrate 33, and the electronic component 34 is sealed with a sealing resin 36.

The assembly of the solid-state imaging device 20 and the circuit board 33 and the like is inserted until the front contact surface of the solid-state imaging device frame 21 contacts the incident surface of the second cover glass 29, and is fixed by the reinforcing resin 37 or the like. .

On the other hand, the second mounting hole 14 is formed in a crescent shape around the first mounting hole 13 and has a large number of light guide fibers.
38 is inserted and fixed. Illumination light from a light source device (not shown) enters from the other end of the light guide fiber 38, and the light flux emitted from one end illuminates the observation site.

According to this structure, the first and second cover glasses 2
Since the parallelism between the incident surface and the image pickup surface is determined only by the parallelism of 8,29, one-sided blurring due to the inclination of the image pickup surface does not occur. Also,
Since the sealing resin 32 only needs to seal the bonding portion, the side surface does not have to have the same shape as the base 22 and the second cover glass 29, and the moldability is very easy. Furthermore, since there is no surrounding structure, the solid-state imaging device 20 has a small outer shape.

FIG. 3 is a diagram showing another configuration of the image pickup device. The solid-state image pickup device 40 is formed by fixing a solid-state image pickup element chip 42 on a ceramic base 41, and on the side of this base 41. Conductive part 43 made of metal plating from top to back
Are formed. Leads 44 are planted on the back surface of the base 41 for each conductive portion 43, and the conductive wire 43 on the upper surface of the base 41 and the bonding pad of the chip 42 are bonded by a bonding wire 45.
Are connected to form a bonding portion. A first cover glass 46 is bonded on the image area of the solid-state imaging device chip 42, and a second cover glass 47 is bonded on the first cover glass 46. The second cover glass 47 is formed larger than the outer shape of the base 41, and is filled with a sealing resin 48 so as to seal the bonding portion from the lower surface of the second cover glass 47. On this occasion,
The periphery of the second cover glass 47 is provided so as to protrude outside the sealing resin 48 as a flange.

According to this configuration, since the periphery of the second cover glass 47 is formed as a flange, the second cover glass 47 can be sandwiched and fixed when the solid-state imaging device 40 is incorporated in an endoscope or the like. Therefore, there is an effect that no compression force is applied to the solid-state image pickup element chip 42 when fixed.

FIG. 4 is a diagram showing a first embodiment of the present invention, in which a solid-state image pickup device 50 is formed by fixing a solid-state image pickup element chip 52 on a base 51. The base 51 has the same shape as the outer shape of the chip 52, and the necessary number of conductive portions 53 for the chip side bonding pads are formed on the back surface of the base 51, and the lead legs 54 are provided corresponding to the conductive portions 53. It is planted on the back of the base 51. And chip side bonding pad and conductive part
53 is a bonding wire 55 that bypasses the side surface of the base 51.
And the bonding portion is formed from the side surface to the back surface of the base 51. In addition, solid-state image sensor chip
A first cover glass 56 is bonded on the image area 52, and a second cover glass 57 larger than the outer shape of the base 51 is bonded on the first cover glass 56. Furthermore,
It is molded with a sealing resin 58 so as to cover the lower surface of the second cover glass 57, the bonding portion, and the lower surface of the base 51.

Generally, the number of leads of a solid-state imaging device is 14 to 20, and the chip side bonding pads can be formed with a pitch of about 0.2 mm, but the lead legs can only be formed with a pitch of about 0.6 mm, and the area required for the lead legs is large. Will be. In the first embodiment, the lead foot 54 is located within the outer shape of the chip 52 as a base.
Since it is formed on the back surface of 51 and the bonding wire 55 is three-dimensionally routed around, it is a solid-state imaging device even if the number of lead legs is large.
The size of 50 can be reduced.

FIG. 5 is a diagram showing a second embodiment of the present invention, in which the solid-state imaging device 60 has a conductive portion provided on the base 61 as compared with the first embodiment.
63 is formed from the back side to the side of the base 61,
A bonding wire 65 is connected between the bonding pad 62 and the side surface of the conductive portion 63. Lead foot 64, first,
The second cover glasses 66 and 67 are the same as in the first embodiment.
Further, a sealing resin 68 is formed so as to cover the bonding wires 65 on the side surfaces of the base 61, the chip 62, and the first cover glass 66.

In the second embodiment, since the sealing resin 68 is not formed on the back surface of the base 61, the thickness of the solid-state imaging device 60 can be reduced as compared with the first embodiment.

The present invention is not limited to the above embodiments, and various modifications can be considered. The first and second cover glasses may be transparent plastic plates such as optical plastic instead of glass. However, it is necessary that the flatness and parallelism of both surfaces are accurately obtained. Further, the first cover glass may be a color filter array, a moire removing filter or an infrared cut filter, and the second cover glass may be a moire removing filter or an infrared cut filter. Further, the sealing resin may seal the bonding portion instead of the low melting point glass.

〔The invention's effect〕

As described above, according to the present invention, a very thin bonding wire is drawn around the side surface of the base member and the solid-state image sensor chip having the same outer shape as the base member and is sealed with the sealing material. I was able to plan.

[Brief description of drawings]

FIG. 1 is a sectional view of a distal end portion of an endoscope having a built-in solid-state imaging device, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a sectional view showing a solid-state imaging device having another structure. FIG. 4 is a sectional view showing a first embodiment of the present invention, FIG. 5 is a sectional view showing a second embodiment of the present invention, and FIG. 6 is a sectional view showing a conventionally considered solid-state imaging device. 20,40,50,60 …… Solid-state imaging device, 22,41,51,61 …… Base, 23,42,52,62 …… Solid-state imaging device chip, 28,46,56,66
...... First cover glass, 29,47,57,67 …… Second cover glass, 32,48,58,68 …… Sealing resin.

Claims (1)

[Claims] 1. A solid having a base member having a conductive portion on a back surface or a side surface, an image area and a bonding pad on the front surface, and having the same outer shape as the base member superposed on the surface of the base member. An image pickup element chip; a bonding wire connecting the bonding pad of the solid-state image pickup element and a conductive portion of the base member; a translucent member that is overlapped and covers the image area of the solid-state image pickup element; A solid-state imaging device comprising: a sealing material that seals a conductive portion, a bonding pad, and a bonding wire; and an input / output terminal provided inside the outline of the solid-state imaging device chip on the back surface side of the base member. apparatus.