JPS61256667A - Close contact type image sensor - Google Patents

Abstract

PURPOSE:To improve the moisture resistance of an image sensor chip and the reliability of fine metal wirings by molding the chip and the wirings with resin. CONSTITUTION:A conductive paste of glazed metal series made of noble metal such as silver or gold on a ceramic insulating substrate 8 is applied by a screen printing method in the desired circuit conductor, baked at a high temperature to form a long so-called thick film circuit conductor layer 9, a die bonding connection agent 11 made of silver paste of resin series is applied on the substrate, an image sensor chip 10 cut by accurately dicing a silicon wafer is linearly arranged thereon, and the agent 11 is thermoset to secure the chip 10. Simultaneously, the chip 10 and a circuit conductor layer 9 are electrically connected by a wire bonding method with fine metal wirings 12, a resin-stopping frame 14 is then secured to surround the chip 10, a molding resin 13 is packed in the frame 14, defoamed and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a contact type image sensor used in an image input device of an OM device such as a facsimile or a copying machine.

BACKGROUND OF THE INVENTION In recent years, there has been remarkable progress in computer equipment such as facsimile machines and copying machines.

Under these circumstances, close-contact image sensors have recently come into wide use with the aim of reducing the size and weight of image input devices for various types of home appliances and improving their performance.

This contact type image sensor is a sensor having a light-receiving portion of the same size as a document for inputting an image, and roughly divided into two types, it has been put into practical use.

One type is the so-called thin-film type, in which a photoconductive film such as cadmium sulfide (CaS) or amorphous silicon is directly deposited on a long glass substrate using thin film technology such as vacuum evaporation, sputtering, or OVD. It was formed.

The other type is called the crystal type, in which a light receiving section consisting of a photodiode, phototransistor, etc. is formed on a silicon substrate using a semiconductor process, and it is a C0D (charge coupled device). Ya, Bipolar X
c-6 Any monolithic type image sensor chip is arranged in a line on a long substrate to form a close contact type.

These two types of contact image sensors each have their own advantages and disadvantages, but in the field of optical devices that require characteristics such as high resolution and medium-high speed reading performance, crystal type image sensors made of COD or bipolar ICs are used. are widely used.

Conventionally, such a contact type image sensor has had a configuration as shown in FIG. 3.

In FIG. 3, 1 is a ceramic insulating substrate, 2 is a thick film circuit conductor layer, 3 is an image sensor chip, 4 is a die-bonding adhesive, 6 is a thin metal wire, 6 is a sealing frame, and 7 is an adhesive.

That is, in the conventional contact image sensor, a silver-based conductive paste is selectively applied onto the main surface of a long ceramic insulating substrate 1 made of alumina or the like using a screen printing method, and then baked at a high temperature. Desired circuit conductor layer 2 by
A plurality of monolithic type image sensor chips 3 such as GCDs and bipolar ICs that have been subjected to precision dicing are arranged in a straight line with high accuracy using a die-bonding adhesive 4 on a so-called thick film circuit board formed with a die-bonding adhesive 4. Each image sensor chip 3 is electrically connected to the thick film circuit board using thin metal wires 6 made of aluminum or the like by the wire bonding method, and furthermore, a wire is attached to the periphery of the image sensor chips 3 arranged in a straight line. A sealing frame 6 made of transparent glass or the like is fixed with an insulating adhesive 7, and the image sensor chip 3 is hermetically sealed.

Problems to be Solved by the Invention However, in the structure of the contact type image sensor as described above, it is necessary to hermetically seal the monolithic type image sensor chip 3 such as COD or bipolar IC. Since the sealing frame 6 is fixed onto a thick film circuit board with many irregularities, it lacks airtight sealing properties.In order to improve sealing properties, increasing the bonding area between the sealing frame 6 and the thick film circuit board causes the board to This has had problems such as increased warpage and the need to increase the dimensions of the thick film circuit board.

In addition, since this image sensor requires hermetic sealing, the wire-bonded thin metal wire 5
Since it is hollow, it has the disadvantage of poor vibration resistance.

The present invention has been made in view of this point, and an object of the present invention is to provide a contact type image sensor having a simple configuration and high reliability.

Means for Solving the Problems In order to solve the above problems, the contact image sensor of the present invention includes a long circuit board having a desired circuit conductor layer on at least one main plane of an insulating substrate. Image sensor chips such as CCDs and bipolar ICs are arranged in a straight line on top, the image sensor chips and the circuit board conductor layer are electrically connected by thin metal wires, and the structure is molded with highly translucent resin. It is something to do.

Operation The contact type image sensor according to the present invention has the above-described structure, so that the image sensor chip and the thin metal wire are protected and fixed by the molding resin. The moisture resistance of thin metal wires and the vibration resistance of thin metal wires have been significantly improved, and a highly reliable contact type image sensor can be realized.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view for explaining a contact type image sensor according to an embodiment of the present invention.

In FIG. 1, 8 is a ceramic insulating substrate, 9 is a thick film circuit conductor layer, 10 is an image sensor chip, 11 is a die-bonding adhesive, 12 is a thin metal wire, 13 is a molding resin,
14 is a resin stopper frame.

The method of configuring the contact type image sensor configured as described above will be described below with reference to FIG.

As shown in FIG. 1, the contact type image sensor of this embodiment is manufactured by first applying a conductive paste made of a noble metal such as silver or gold and not having a metal glaze onto a ceramic insulating substrate 8, and then printing a desired circuit conductor by a screen printing method. A long so-called thick film circuit conductor layer 9 is formed by coating the circuit board on top and firing at a high temperature.A die bonding adhesive 11 made of resin-based silver paste is coated on this circuit board, and then Image sensor chips 1o cut from a silicon wafer by high-precision dicing are arranged in a straight line, and adhesive 11
The image sensor chip 1o is fixed by heating and hardening, and the image sensor chip 1o and the circuit conductor layer 9 are bonded using a thin metal wire 12 such as an aluminum wire or a gold wire using a normal wire method such as an ultrasonic method or a thermocompression bonding method. Electrical connection is made by a bonding method, and then the mold resin 13
A resin stopper frame 14 is fixed to surround the image sensor chip 1o to prevent the image sensor chip 1o from flowing out, and the resin stopper frame 14 is filled with a molding resin 13 made of epoxy resin with excellent translucency. By defoaming and curing, a contact image sensor was constructed.

As described above, in the contact type image sensor according to this embodiment, the image sensor chip 10 and the thin metal wire 12 are protectively coated with the mold resin 13, so that a contact type image sensor with excellent moisture resistance and vibration resistance is realized. It is something that can be done.

Next, FIG. 2 shows the second embodiment.
This contact type image sensor has a configuration that is an improvement on the first embodiment described above, and a glass plate 16 with excellent translucency is bonded to the upper surface of a molded resin 13, thereby reducing COD.
The effect is that the amount of light irradiated onto the light-receiving surface of the image sensor chip 1o, such as a bipolar IC or the like, is made uniform.

Effects of the Invention As described above, the contact type image sensor according to the present invention can be applied to COD or bipolar I mounted on a long circuit board.
It has a structure in which an image sensor chip such as C and a thin metal wire are molded with resin, and this structure has the effect of dramatically improving the moisture resistance of the image sensor chip and the reliability of the thin metal wire. It is of great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a contact type image sensor according to a first embodiment of the present invention, Fig. 2 is a sectional view of a contact type image sensor for explaining the second embodiment, and Fig. 3 is a conventional example. FIG. 2 is a cross-sectional view of a contact image sensor. 8... Ceramic insulating substrate, 9... Thick film circuit conductor layer, 1o... Image sensor chip, 11... Adhesive for die bonding, 12...・・・
...Thin metal wire, 13...Mold resin, 14.
...Resin stopper frame. Name of agent: Patent attorney Toshio Nakao and 1 other person81
0. Semutsu 2 Koku Line" 1 fork 1st figure 1? ...Metal mMLD...Mold #Island/4. ,,Kei TG Stop 4 Tei Figure 2 Figure 3

Claims (1)

[Claims] Image sensor chips are arranged linearly on a long circuit board having a desired circuit conductor layer on at least one main plane of the insulating substrate and are electrically connected to the circuit conductor layer by a thin metal wire, A contact image sensor characterized in that the image sensor chip is molded with a molding resin.