JPH0693504B2 - Image sensor manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for manufacturing an image sensor, and more particularly to a method for mounting a solid-state image sensor such as a CCD on a high resistance substrate.

[Technical background of the invention and its problems]

2. Description of the Related Art In recent years, image sensors, particularly contact image sensors, have been actively developed in order to reduce the size of image reading apparatuses used in facsimiles and the like. Many of these contact image sensors use a rod lens array for a lens system to form an erecting equal-magnification image of a document on a photo cell array provided with the same size as the document, and obtain image information of the document from the photo cell array. Take structure. Therefore, according to this structure, since the distance between the object images of the rod lens array is as short as about 17 mm, there is an advantage that the size of the device can be greatly reduced.

There are roughly two types of contact image sensors.
The first contact-type image sensor is one in which a photoconductive film of CdSe, CdS or the like having the same size as the original is provided on an insulating substrate of alumina or the like, or an amorphous silicon film is provided. However, the first contact image sensor
There are problems with various characteristics such as responsiveness and resolution. A second contact-type image sensor using a solid-state imaging device such as a CCD is a device that avoids this problem. Although this second contact-type image sensor has high speed and high resolution, it has the following drawbacks. That is, the solid-state image sensor is small, and the maximum width of the sensor unit is about 60 mm. Therefore, in order to read an equal-magnification image of the same size as the original, a plurality of solid-state image pickup devices arranged in a staggered manner from the center of the photocell array as disclosed in Japanese Patent Laid-Open No. 57-129065 are staggered, and It is necessary to have a structure in which the photo cell arrays of the respective chips are arranged in a direction in which they approach each other.

By the way, when the position accuracy of the staggered solid-state image pickup devices is poor, the image information becomes discontinuous at the adjacent portion between the solid-state image pickup devices, that is, the connection portion of the image information, and the read image is distorted. There is danger. Therefore, in an image sensor in which a plurality of solid-state image pickup devices are arranged in a staggered pattern, it is required to arrange the solid-state image pickup devices with high positional accuracy without affecting the image quality. In addition to the contact type image sensor like this, the CCD or MOS type IC sensor conventionally used in combination with a spherical lens has a solid-state image sensor as an insulating substrate in order to easily adjust the optical system. It is necessary to arrange them accurately with respect to the outer shape of.

In general, a solid-state image sensor needs to be electrically connected from the back surface, and is fixed on an insulating substrate by using a conductive adhesive to satisfy this. However, the adhesive used as the conductive adhesive is generally a heat-curable adhesive as represented by an epoxy thermosetting adhesive. When this heat-curable adhesive is used, gas is generated from the adhesive during curing even if the solid-state image sensor is accurately arranged on the substrate before the adhesive is cured, and this gas is generated. May cause the solid-state image sensor to move, or the viscosity may drop before curing and the adhesive may flow out, causing the solid-state image sensor to move during curing of the adhesive, causing a deviation from the planned position. There is a risk that it will occur. Therefore, it is extremely difficult for the solid-state imaging device to maintain its positional accuracy even after the adhesive is cured.

[Object of the Invention]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing an image sensor in which a read image has no distortion and high-quality image information is obtained and the optical system can be easily adjusted. To do.

[Outline of Invention]

According to the method of manufacturing an image sensor of the present invention, at least one solid-state imaging device is mounted on at least a part of a mounting surface end portion facing the solid-state imaging device of the adhesive high-resistance base material and a mounting surface adjacent to the mounting surface end part. A step of applying a quick-curing adhesive near the outside of the surface, a step of applying a heat-curing conductive adhesive so as to cover a portion of the mounting surface on which the quick-curing adhesive has not been applied, and a solid-state image sensor Is placed on the fast-curing adhesive and the heat-curing conductive adhesive, and the solid-state image sensor is fixed on the high-resistance substrate with the fast-curing adhesive, and the heat-curing conductive adhesive is cured. And a step of fixing the solid-state imaging device on the high resistance substrate. More specifically, an epoxy / acrylic UV curable adhesive is attached to at least one point on the die pad provided on the alumina substrate, and an epoxy heat curable conductive adhesive is attached to the rest. The solid-state image sensor is mounted on this adhesive. Therefore, first, the epoxy-acrylic UV-curable adhesive is irradiated with ultraviolet rays, and the solid-state imaging device is temporarily fixed on the alumina substrate, and then heated to cure the epoxy-based heat-curable conductive adhesive to form the solid-state imaging device. Fix it.
Therefore, the solid-state imaging device can be firmly and accurately fixed to the alumina base plate without damaging the electrical connection.

Example of Invention

An embodiment of the image sensor of the present invention will be described with reference to FIGS. 1 and 2 (a) and (b) below.

2 (a) and 2 (b), an image sensor according to the present invention is schematically shown by a CCD arranged on an alumina substrate (5).
Apply epoxy to the die pad (not shown)
CCD (1) via an acrylic UV curable adhesive (not shown) and an epoxy heat curable adhesive (not shown)
a), (1b), ... (1n) are fixedly configured. The CCDs (1a), (1b), ... (1 _n-1 ) are arranged in a staggered pattern so that the photocell array (2) is located on two parallel straight lines (3) and (4). . This straight line (3),
(4) CDD (1a), (1b), ... (1 _n-1 ) and (1
b), (1d), ... (1n) on the photo cell array (2), the image on the scanning line (8) and the scanning line (9) on the document surface (7) is equal by the rod lens array (6). The image is doubled. As a result, CCD (1a) on line (3),
(1b), ... (1 _n-1 ) to scan line (8) on the document surface (7)
The above image information is obtained. Similarly, image information on the scanning line (9) is obtained from the solid-state image pickup devices (1b), (1d), ... (1n) on the straight line (4). Further, the CC of the image sensor of the present invention
Since the D (1a), (1b), ... (1n) are accurately arranged on the alumina substrate (5), the original feeding direction (10)
Read the scan line (9) above for CCD (1b), (1
d), ... Delays the image information from (1n) by the amount of image information in the interval between the scanning line (8) and the scanning line (9) in the memory or the like, and CCDs (1a), (1c) ,. The image information from (1 _n-1 ) is electrically connected to obtain the image information on the scanning line (8) as one time-series signal.

Next, the fixing state of the CCDs (1a), (1b), ... (1n) and the alumina substrate (5) will be described with reference to FIG. In FIG. 1, an epoxy / acrylic UV-curable adhesive (12) as a quick-curing adhesive is used on the alumina substrate (5) at the center of the CCD (1a), (1b), ... (1n). The other parts of the CCDs (1a), (1b), ... (1n) are fixed, and are fixed by an epoxy heat-curable conductive adhesive (11).

With the above configuration, since the CCDs (1a), (1b), ... (1n) are accurately arranged on the alumina substrate (5), a contact image sensor with good image quality can be obtained. In addition, CCD (1a), (1b),… (1
Since n) can be fixed, an image sensor in which the optical system can be easily adjusted can be obtained. In addition, CCD (1
The die pads of a), (1b), ... (1n) and the alumina substrate (5) mainly use an epoxy-based heat-curable conductive adhesive (11), so that the CCD (1a), (1b) ,… (1
n) can be sufficiently electrically connected to the die pad.

Next, referring to FIG. 3, the CCD (1a), (1
b), ... (1n) How to mount is explained. In FIG. 3, the CCD (1b) is fixed with a collet (13), and is coated with an epoxy heat-curable conductive adhesive (11) and an epoxy-acrylic UV-curable adhesive (12). It is accurately arranged on the mounting surface of the alumina substrate (5). After this, the epoxy / acrylic UV curable adhesive (12) in the center of the CCD (1b) is irradiated with UV light (14) to produce an epoxy / acrylic UV curable adhesive (12).
The part of the CCD (1b) protruding from the mounting surface is cured, and the CCD (1b) is temporarily fixed on the alumina substrate (5) while maintaining its positional accuracy. After this, collet (13)
Is removed, and the whole is further heated to cure the epoxy heat-curable conductive adhesive (11). When heating, CCD (1
b) Epoxy / acrylic UV curable adhesive (12)
Since it is fixed at the protruding part of the CCD (1b), no excessive force is applied to the CCD (1b), so it does not move even during heat curing of the adhesive. At this time, needless to say, when the epoxy / acrylic ultraviolet curing adhesive (12) that is cured by heating is used, the effect is further enhanced.

By the manufacturing method described above, the CCD (1b) maintains sufficient positional accuracy even after the epoxy-based heat-curable conductive adhesive (11) is cured, and the entire back surface of the CCD (1b) is fixed to the alumina substrate (5). The CCD (1b) can be sufficiently electrically connected from the back surface of the CCD (1b). In addition, CCD (1a), (1c), (1
Similarly, d), ... (1 _n-1 ), (1 n) are also fixed on the alumina substrate.

Further, the method of applying the adhesives (11) and (12) is not limited to the above-mentioned method, and the adhesives (11) and (12) are alternately arranged or the adhesive (11). Alternatively, the adhesive may be applied to the back surface of the CCD (1b) and the adhesive (12) may be applied to the peripheral portion of the CCD (1b). In particular, the latter method has the effect of completely irradiating the adhesive (12) with ultraviolet rays, so that it is not necessary to use the adhesive (12) having the property of heat curing.

The method of manufacturing the image sensor of the present invention is not limited to the above-described embodiment, and for example, the solid-state image pickup elements are arranged in a straight line, the solid-state image pickup element is one, or conventionally used. It can also be used for a CCD or MOS type IC sensor mounted with a solid-state image sensor based on the outer shape of the substrate. In other words, the present invention can be variously modified and implemented without departing from the scope of the invention.

〔The invention's effect〕

According to the method of manufacturing an image sensor of the present invention, at least one solid-state imaging device is arranged on a high-resistance substrate with a quick-curing adhesive and a heat-curing adhesive, so that a plurality of solid-state imaging devices are used. The position accuracy of the solid-state image sensor required in the image sensor used can be easily realized, and an image sensor with high image quality can be obtained.

[Brief description of drawings]

FIG. 1 is an enlarged schematic sectional view of an essential part showing an embodiment of an image sensor of the present invention, and FIGS. 2 (a) and 2 (b) are schematic views for explaining an embodiment of the image sensor of the present invention. , FIG. 3 is a simplified sectional view for explaining a mounting method of the image sensor shown in FIG. (1a), (1b), ..., (1n) ... CCD (2) ... Photo cell array (5) ... Alumina substrate (11) ... Epoxy heat curing adhesive (12) ... Epoxy / acrylic UV curing adhesive Agent

Claims (2)

[Claims] 1. A method of manufacturing an image sensor in which at least one solid-state imaging device is mounted on a high-resistance base material, wherein at least one end of a mounting surface of the high-resistance base material facing the solid-state imaging device. Part and a portion of the mounting surface adjacent to the outside of the mounting surface adjacent to the mounting surface, and the heat-curing conductive material so as to cover the portion of the mounting surface not coated with the rapid curing adhesive. A step of applying a conductive adhesive, arranging the solid-state imaging device on the fast-curing adhesive and the heat-curing conductive adhesive, and placing the solid-state imaging device on the high-resistance substrate in the fast-curing type. A method of manufacturing an image sensor, comprising: a step of fixing with an adhesive; and a step of curing the heat-curable conductive adhesive to fix the solid-state imaging device on the high-resistance substrate. 2. The step of fixing the solid-state imaging device with the fast-curing adhesive is a step of curing the fast-curing adhesive by irradiating ultraviolet rays to fix the solid-state imaging element. An image sensor manufacturing method according to claim 1.