JPH07114266B2 - Contact image sensor assembly method - Google Patents

Description

The present invention relates to a method for assembling a contact image sensor used in an input device of OA equipment such as a facsimile machine and a copying machine.

(Prior Art) In recent years, OA equipment has made rapid progress, but in order to reduce the size and weight of these OA equipment, the need for a contact image sensor as an input device is increasing.

In general, there are roughly two types of contact image sensors, one of which is called a thin film type, and a glass substrate is used as a base on the surface of which a thin film technology such as vacuum deposition or sputtering is fully utilized. , A CdS-based photoconductive film is formed.

The other one is called a crystal type, and is one in which an array of photodiodes, phototransistors, or the like is formed as a light detection element on a silicon substrate, and a video signal is obtained by operation in a charge storage mode. , Typically CC
This is a contact-type image sensor in which a plurality of image sensor chips such as D and bipolar ICs are linearly arranged on a long ceramic circuit board.

The above-mentioned two types of contact image sensors each have advantages and disadvantages, and they are used properly according to the application. However, as the demand for higher performance of OA equipment has increased in recent years, performance such as resolution and reading speed has increased. Excellent CCD and bipolar IC
The contact type image sensor of the crystal type such as has attracted attention and has been widely used.

An assembling method of a conventional contact type image sensor of a crystal type will be described with reference to FIG. 4 by taking the “contact type image sensor announced on October 26, 59, Technical Report of the Television Society” as an example.

FIG. 4 is a cross-sectional view of a main part of a conventional contact image sensor, in which a ceramic insulating substrate 1 made of alumina or the like is processed into a long shape, and a thick film technique is used on the ceramic insulating substrate 1. A thick film circuit board on which a circuit conductor layer 2 made of a noble metal such as gold or silver is formed, a thermosetting die-bonding adhesive 3 is applied onto the thick film circuit board, and the adhesive 3 is applied onto the thick film circuit board. A plurality of image sensor chips 4 such as bipolar ICs and CCDs, which are processed from a silicon wafer by using high precision dicing technology, are linearly arranged, and the die bonding adhesive 3 is heat-cured and fixed.

Next, after electrically connecting the electrode terminal of each image sensor chip 4 and the circuit conductor layer 2 using a wire 5 such as aluminum or a gold wire, a ceramic-made so as to surround the image sensor chip 4. The sealing frame 6 is adhered by using the sealing material 7, the glass plate 8 is further adhered on the sealing frame 6, and the image sensor chip 4 is assembled by a hermetically sealing method.

(Problems to be Solved by the Invention) In the conventional contact type image sensor, since the ceramic insulating substrate 1 is used as the substrate on which the image sensor chips are arranged, the cost becomes higher as the length increases, and For lengthening, warp, swell, or swell in the ceramic insulating substrate 1.
Due to bending, etc., the plane accuracy will be significantly reduced.
There is a problem that the performance as an image sensor is deteriorated and the airtightness of the bonding surface between the sealing frame 6 and the ceramic insulating substrate 1 and the glass plate 8 is poor, resulting in lack of reliability.

Further, in the contact type image sensor, when connecting to another system, a lead terminal is soldered from the thick film circuit conductor layer 2 formed on the ceramic insulating substrate 1, and the lead terminal is connected to another lead terminal. The connection is performed by a method of connecting, but such a method has a problem that the connection work is troublesome and the solder connection is unreliable.

(Means for Solving Problems) In order to solve the above problems, the present invention provides a flexible wiring board in which a desired circuit conductor layer is formed on a polyimide film on the main surface of a transparent glass substrate. Glued,
Provided is a method of assembling a contact-type image sensor in which a plurality of image sensor chips are linearly arranged on the flexible wiring and electrically connected, and the image sensor chips are hermetically sealed in a glass container. To do.

(Function) According to the present invention, since a substrate in which a flexible wiring board made of a polyimide film is bonded to a glass substrate is used as a base substrate, the planar accuracy is stabilized by lengthening, and the glass container is excellent. In addition to providing excellent airtight sealing property, when connecting to another system in which a circuit element is mounted on the printed wiring board, as shown in FIG. 2, the glass substrate is protruded at both ends orthogonal to the longitudinal direction. The connection terminals formed on the flexible wiring board can be freely bent and directly connected using a connector or the like, so that workability and reliability of connection can be improved.

(Example) An assembling method of the contact image sensor of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a cross-sectional view of a main part of a contact image sensor according to the first embodiment of the present invention, and FIG. 2 is a perspective view for explaining a method of assembling the contact image sensor. The glass substrate 9 having the above is cut into a predetermined size, and the flexible wiring board 10 on which the desired circuit conductor layer 2 is formed is attached onto the glass substrate 9 by using a thermosetting adhesive 11. In the present embodiment, a polyimide film is used for the flexible wiring board 10, and a desired circuit conductor layer 2 is formed by a photoetching method on a copper-clad substrate in which copper foil is adhered to the surface of the flexible wiring board 10, or A flexible wiring board 10 in which the circuit conductor layers 2 are formed on both front and back surfaces of the film substrate is prepared by performing hole plating if necessary, and gold plating is applied to a part of the circuit conductor layer 2 so that wire bonding can be performed.

Next, a die-bonding adhesive 3 such as silver paste is applied at a predetermined position on the flexible wiring board 10 by a screen printing method or a die stamping method, and a large number of die-bonding adhesives 3 are separately provided on the die-bonding adhesive 3. An image sensor chip 4 such as a CCD or a bipolar IC, which has been cut and processed by a highly accurate dicing technique from the taken silicon wafer, is mounted, and a plurality of the image sensor chips 4 are linearly arranged, and then a die bonding adhesive 3 Cure.

Next, the electrode terminal of each image sensor chip 4 and the circuit conductor layer 2 of the flexible wiring board 10 are wire-bonded to each other.
It is electrically connected using a wire 5 of aluminum or gold.

Then, the arranged image sensor chips 4 are covered with a glass container 12 for sealing, adhered with an epoxy sealant 7 interposed therebetween, and hermetically sealed to assemble the adhesive image sensor.

FIG. 3 is a sectional view of a contact type image sensor according to a second embodiment of the present invention, in which a part of the flexible wiring board 10 is hollowed out, and an image sensor chip and a glass substrate are formed by using an ultraviolet curing adhesive. By adhering 9 and 9, the workability of the die bonding process is improved and the productivity can be improved. Note that the circuit board having the above-mentioned configuration is used and the same as in the first embodiment except that a plurality of image sensor chips 4 are linearly arranged and fixed on the exposed portion of the glass substrate 9, and therefore detailed description will be made. Omit it.

(Effect of the Invention) As described above, according to the present invention, since a substrate in which a flexible wiring board made of a polyimide film is bonded to a glass substrate is used as a base substrate, the planar accuracy is stabilized by lengthening. As a result, a good hermetic sealing property can be obtained by the glass container, and when connecting to another system in which the circuit element is mounted on the printed wiring board, as shown in FIG. It is possible to freely fold the connection terminals formed on the flexible wiring board protruding at both ends orthogonal to each other and directly connect them by using a connector or the like, which has the effect of improving the workability and reliability of the connection. is there.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a contact image sensor according to a first embodiment of the present invention, FIG. 2 is a perspective view of a part of the contact image sensor, and FIG. 3 is a perspective view of the present invention. FIG. 4 is a sectional view of a main part of a contact image sensor according to the second embodiment, and FIG. 4 is a sectional view of a main part of a conventional contact image sensor. 1 ... Ceramic insulating substrate, 2 ... Circuit conductor layer, 3 ...
Die bond adhesive, 4 ... Image sensor chip, 5
...... Wire, 6 ...... Sealing frame, 7 ...... Sealing material, 8 ...... Glass plate, 9 ...... Glass substrate, 10 ...... Flexible wiring board, 11 ...... Adhesive, 12 ...... Sealing glass container.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazumi Sadamatsu, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Shinji Fujiwara, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Toshiaki Hashiguchi, 1006, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-60-117696 (JP, A) JP-A-58-97860 (JP, A) 59-132653 (JP, U)

Claims (3)

[Claims] 1. A flexible wiring board having a desired circuit conductor layer formed on a polyimide film is adhered onto a main surface of a glass substrate having transparency, and a plurality of image sensor chips are mounted on the flexible wiring board. A method for assembling a contact image sensor, characterized in that the image sensor chip is hermetically sealed in a glass container while being fixed in a linear arrangement and electrically connected. 2. The contact type image sensor according to claim 1, wherein a part of the glass substrate is exposed, and image sensor chips are arrayed and fixed on the exposed portion. Assembly method. 3. The method of assembling a contact image sensor according to claim 2, wherein the image sensor chips arranged on the glass substrate are fixed with an ultraviolet curing resin.