JPH0318343A - Solid-state image pickup element assembly for electronic endoscope - Google Patents

Abstract

PURPOSE:To shorten the thickness dimension of a whole solid-state image pickup element assembly by forming a through hole and an electrode on a thin film substrate, making the photodetecting surface of the solid-state image pickup element correspond to the through hole and directly adhering an electrode, which is provided on a surface, to the electrode of the thin film substrate. CONSTITUTION:A rectangular through hole 17 is formed in the central part of a thin film substrate 16 and a wiring pattern 19 is formed on the surface and extended to a flap part 18. Then, a cable 20 is connected. An electrode part 21 is formed in the wiring pattern 19. For a solid-state image pickup element 22, a photodetecting surface 22a is formed in the central part and faced to the through hole 17 and an electrode 23 is directly joined to the electrode part 21 of the wiring pattern 19 in the side of the substrate 16. For either the electrode 23 or electrode part 21, a bump is formed by gold and indium alloy solder, etc., and by pressurizing and welding the bump part under a heating state, the electrode 23 and electrode part 21 are welded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state image sensor assembly for an electronic endoscope used for medical, industrial, etc. purposes. [Prior Art J] As an imaging means in an electronic endoscope, a solid-state imaging device such as a CCD is used. This solid-state imaging device is provided at the tip of an insertion section that is inserted into the body. A solid-state image sensor assembly is constructed by mounting the solid-state image sensor on a substrate and placing it inside a package equipped with a transparent window for light entrance equipped with a protective glass. The assembly is fixedly attached to the lens barrel of the objective lens. Here, the substrate on which the solid-state image sensor is attached is a flat one, a predetermined wiring pattern is formed on this substrate, and a wire bonding means is used to connect the wiring part and the electrode part on the surface of the solid-state image sensor. I am trying to wire it according to the following. [Problems to be Solved by the Invention] In the case of a bronchoscope, etc. that is inserted into the bronchus, it is necessary to reduce the diameter of the insertion part as much as possible, and to shorten the length of the hard part. There is. For this purpose, the solid-state image sensor assembly, which is a built-in component of the insertion section, must be miniaturized. In recent years, solid-state imaging devices with significantly improved integration have been developed, and are mounted on extremely small chips of about 1 to 2 mm.
For example, devices with tens of thousands of pixels are now being used. Therefore, by using such a small-sized element, it is possible to downsize the solid-state image sensor assembly. However, as described above, even if a small-sized solid-state image sensor is used, it is not necessarily possible to reduce the size of the entire solid-state image sensor assembly to a commensurate degree. That is, the solid-state image sensor assembly has a three-layer structure in which the solid-state image sensor is mounted on a substrate, and a protective glass is provided to cover the light-receiving surface of the solid-state image sensor. Since this electrode is formed on the surface side, this electrode and the electrode on the substrate side are connected by wire bonding means. here,
According to the wire bonder means, since the wiring is attached in an arch-shaped protruding state, it is necessary to provide a certain amount of clearance between the light-receiving surface of the solid-state image sensor and the protective glass. As a result, the overall thickness of the solid-state image pickup device assembly becomes large, which has the disadvantage that it is impossible to shorten the length of the hard portion at the distal end of the insertion portion. Furthermore, if wire bonding is used to connect the substrate and the solid-state image sensor, it is necessary to secure a space on the substrate to enable wire bonding. Therefore, there are drawbacks that are disadvantageous in reducing the diameter of the insertion portion of the endoscope. The present invention has been made in view of the above points, and an object thereof is to provide a solid-state image sensor assembly for an electronic endoscope that is small and compact. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention comprises a transparent support plate, a thin film substrate attached to the surface of the transparent support plate, and a solid-state image sensor, A through hole and an electrode are formed in the substrate, and the light-receiving surface of the solid-state imaging device corresponds to the through-hole, and the electrode provided on the surface of the solid-state imaging device is directly bonded to the electrode of the thin film substrate. Its distinctive feature is that it has a set of precepts. [Function 1] Here, the thin film substrate only needs to be able to form a wiring pattern on its surface, and therefore the thickness can be almost ignored. The thickness of the entire assembly is approximately the sum of the thickness of the transparent support plate and the thickness of the solid-state image sensor. Furthermore, the electrodes formed on the surface of the solid-state imaging device can be directly connected to the electrodes of the substrate without using wire bonding means. Therefore, it has become possible to significantly reduce the overall thickness of the solid-state image sensor assembly, and when this solid-state image sensor assembly is installed inside the insertion section,
The hard part can be shortened. Furthermore, it is necessary to connect the wiring pattern provided on the thin film substrate to the cable, but by providing the wiring pattern on the thin film substrate in this way, connection to the cable becomes extremely easy. [Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. First, FIG. 1 shows a schematic configuration of the distal end portion of the insertion section of the electronic endoscope. In the figure, reference numeral 10 denotes the main body of the distal end of the insertion section, and the main body 10 of the distal end has a through hole l1, and the through hole 11 has an inner cylinder 12 for supporting the objective lens L and a lens barrel. An outer cylinder 13 is attached. A solid-state image sensing device assembly 14 serving as an image sensing means is fixedly provided at the end of the lens barrel outer tube 13. The solid-state image sensor assembly 14 is constructed as shown in FIGS. 2 and 3. That is, reference numeral 15 indicates a transparent support plate made of flat glass, and on one side of this transparent support plate 15, as shown in FIG. 4, a flexible thin film substrate l6 such as a resin film is pasted. There is. A rectangular through hole 17 is formed in the center of the thin film substrate 16, and the through hole 17 is formed in a rectangular shape.
Other parts are shielded from light. The thin film substrate 16 also has a plurality of folded flap portions 18 that project outward from the outer peripheral edge of the transparent support plate 15.
It is equipped with A wiring pattern 19 is formed on the surface of the thin film substrate 16.
is adapted to extend across the flap portion l8. This wiring pattern 19 is used for the flap I8.
A cable 20 is connected to the flap portion 18 . Further, an electrode portion 21 is formed on the wiring pattern l9. Next, a solid-state image sensor 22 is attached to the thin film substrate 16. As is clear from FIG. 5, this solid-state image sensor 22 has a light-receiving surface 22a formed in the center thereof, and a plurality of electrodes 23 are formed around the light-receiving surface 22a. The solid-state image sensor 22 has a light-receiving surface 22
a to face the through hole 17, and the electrode 23 to the substrate 16.
He is trying to connect it directly to the electrode part 21 in the wiring pattern 19 of the example. Here, both electrodes 23. 21, bumps of gold, insium alloy, solder, etc. are formed on either the electrode 23 of the solid-state image sensor 22 or the electrode portion 2l of the wiring pattern 19 (in this example, (the electrode 23 side has a hanging electrode structure), and the electrode 23 of the solid-state image sensor 22 having the bump formed thereon is connected to the electrode 2 of the thin film substrate 16.
The electrode 23 and the electrode part 21 are bonded together by aligning the bump parts 1 and 23 and melting the bump part by applying pressure under a heated state, so-called hang bonding. Note that an Oha flow train electrode is provided on the opposite side of the light-receiving surface of the solid-state image sensor 19, and this electrode and the thin film substrate l6 are connected by wire bonding. Moreover, the solid-state image sensor 2 on this substrate 16
A buffer amplifier 26 can be attached to the attachment side of 2. With the solid-state imaging device 22 mounted on the substrate 16 in this manner, the mounting portion of the solid-state imaging device 22 and the mounting portion of the Huffer amplifier 26 are entirely covered and sealed with a sealing resin 25 made of epoxy resin or the like. The solid-state image sensor 22 and the electrodes 21. It is configured to protect the connection parts of 23, etc. Note that the transparent support plate 15 and the thin film substrate 1 attached thereto
6 is formed in a substantially semicircular shape, and has a structure in which downwardly extending portions 15a, 15a, 16a, and 16a are provided at both ends thereof. This prevents interference with the treatment instrument insertion channel T, the light guide δ, and other built-in objects that are inserted into the insertion hole. He is in charge. This embodiment is constructed as described above, and in order to form the solid-state image sensor assembly 14, first, the thin film substrate 16 on which the wiring pattern 19 is formed is bonded to the transparent support plate 15 to integrate it. . Then, this thin film substrate 16
The solid-state image sensor 22 is placed so that its light-receiving surface 22a faces the through hole l6, and each electrode 23 is connected to the electrode portion 2 of the wiring pattern 19.
The electrode 23 and the electrode part 21 are aligned by heating and pressurizing the electrode part to melt the electrode 23 constituting the bump electrode.
Glue the . Here, the solid-state image sensor 22 usually has an electrode 2 on its surface side.
By providing the wiring pattern 19 on the back side of the substrate l6, the electrodes 23.3 are formed without using wire bonding means. 21 can be directly connected. 9 1 0 At the same time, the cable 20 is connected to the flap portion 18 of the thin film substrate 16, and the flap portion 18 is folded back. Thus, by connecting the cable 20 at the flap portion 18 extending outward from the transparent support plate 15, the cable 20 can be connected extremely easily. Further, a J buffer amplifier 26 is mounted on the substrate 16, and a portion of the solid-state image sensor 22 is sealed with a sealing resin 25. After some time,
By fixing the surface of the transparent support plate 15 opposite to the side to which the thin film substrate 16 is attached to the end of the lens barrel outer tube 13 of the objective lens L, the solid-state image sensor assembly 14 can be attached to the endoscope. It can be attached to the tip of the insertion section. In this way, the solid-state image sensor 22 is mounted on the transparent support plate 15.
The thickness of the solid-state image sensor assembly 14 is approximately equal to the thickness of the transparent support plate 15 and the solid-state image sensor 22 because the solid-state image sensor assembly 14 is directly bump-bonded to the thin-film substrate 16 attached to the transparent support plate 15 without intervening wiring. It will be equivalent to 1,000 minutes. Therefore, compared to the conventional technology, which has a three-layer structure consisting of the substrate, the solid-state image sensor, and the protective glass, and in which a clearance is provided between the solid-state image sensor and the protective glass by the amount of protruding wiring due to wire bonding, It becomes possible to significantly shorten the thickness dimension. Furthermore, since the solid-state image sensor 22 and the thin film substrate 16 are connected by bump bonding, the thin film substrate 16 and the transparent support plate 1
5 only needs to have the minimum width necessary to form the wiring pattern 19, and there is no need to provide extra space as in the case of wire bonding. 15 can be reduced, which is advantageous when reducing the diameter of the insertion portion. Here, as is well known, the tip body 10 of the insertion portion of the endoscope has an angled portion and a soft portion successively connected thereto. That is, the rigid portion R, which cannot be bent in a manner similar to that of the insertion path, is provided so as to surround the solid-state image sensor assembly 14 in order to protect the solid-state image sensor assembly 14 from the tip body 10. The end of the hard cylindrical body 10a. Therefore, by making the solid-state imaging device assembly 14 thinner, the length of the cylindrical body 10a in the axial direction can be shortened, and the dimensions of the rigid portion R can be shortened. In particular, in the case of endoscopes, even if the reduction in the dimension of the rigid part R is extremely small, such as less than 1 inch, it is difficult to observe diseases when the endoscope is inserted into the patient's body. This has an extremely important effect from the viewpoint of operability as an electronic endoscope. Effects of the Invention As explained above, the present invention, when mounting a solid-state image element on a substrate, forms the substrate in the form of a thin film with through holes, and attaches the thin film substrate to a transparent support plate. The solid-state image sensor was attached to the substrate, aligned with the through hole on the light-receiving surface, and the electrodes formed on the light-receiving surface were bonded to the electrodes on the substrate. , the solid-state image sensor assembly can be made extremely thin to approximately the same extent as the total thickness of the transparent support plate and the solid-state image sensor, and the axial dimension of the hard part at the tip of the endoscope can be reduced. In addition, since there is no need to ensure the wiring distance in the wire bonding means, it is only necessary to make the thin film substrate and transparent support plate have the minimum area necessary to form the wiring pattern. As a result, the area can be shortened, and the diameter of the insertion portion can be reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a sectional view of the distal end of the insertion section of an endoscope, FIG. 2 is an exploded perspective view of the solid-state image sensor assembly, and FIG. 3 is a side view thereof. , FIG. 4 is an external view of the thin film substrate, and FIG. 5 is an external view of the solid-state imaging device. 10: Tip main body, 12: Lens barrel inner tube, 13: Lens barrel outer tube,
14: Solid-state image sensor assembly, 15: Transparent support plate, 1
6. Thin film substrate, 17: Through hole, 19: Wiring pattern, 20
: Ketzl, 21: Electrode part, 22: Solid-state image sensor, 22
a: Light receiving surface, 23: Electrode. 1 5

Claims (1)

[Claims] a transparent support plate; a thin film substrate adhered to the surface of the transparent support plate;
a solid-state imaging device, a through-hole and an electrode are formed in the thin film substrate, the light-receiving surface of the solid-state imaging device corresponds to the through-hole, and the electrode provided on the surface of the solid-state imaging device corresponds to the through-hole. A solid-state image sensor assembly for an electronic endoscope, characterized in that it is configured to be directly bonded to an electrode on a thin film substrate.