JPH04345066A - Linear image sensor - Google Patents

Abstract

PURPOSE:To obtain a linear image sensor capable of corresponding with both a close contact type and a completely close contact type. CONSTITUTION:A transparent sheet substrate 11 on which surface a circuit conductor layer 12 is formed, and a semiconductor element having a photodetector 17 which is mounted on the substrate 11 surface via photo-setting type insulative resin 15 are provided. The semiconductor element is mounted with its face down, and electrodes formed on the element abut against the circuit conductor layer 12. At least a part of the circuit conductor layer 12 on the transparent sheet substrate 11 is connected with a circuit board 16, and the transparent sheet substrate is retained by the circuit board 16. Hence one kind of manufacturing equipment of an image sensor can be commonly used, so that initial investment can be reduced.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an image sensor that converts an optical image into an electrical signal, and relates to a one-dimensional image sensor that is compatible with the width direction of a document and is suitable for facsimile machines, image readers, digital copying machines, etc. .

0002

[Prior Art] Conventionally, image sensors that convert image information into electrical signals have been commercialized as a reduced type using a one-dimensional CCD element and a one-dimensional image sensor using a long sensor of the same size. . Among these, the latter one-dimensional image sensor using a long sensor has excellent features such as high light utilization, high-speed reading, and the ability to design a small optical system. Such image sensors include a close-contact type image sensor that uses a convergent rod lens array, which is a same-magnification optical lens, and a completely close-contact type image sensor that does not use an optical lens. The latter fully contact image sensor is
Since no converging rod lens array is required, it is inexpensive, and the device can be more easily miniaturized, so it has come into practical use in facsimiles.

0003

[Problems to be Solved by the Invention] However, in a one-dimensional image sensor using a long sensor as described above, in a fully contact type image sensor, the distance between the object to be detected (read original) and the light receiving element is approximately 50 μm. Because there is
Unlike a contact image sensor using a rod lens array, it was necessary to design and manufacture an image sensor separately. For this reason, complicated management such as separate production equipment and frequent model switching is required, and a large amount of capital investment is required.

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a light-transmitting sheet substrate on which a circuit conductor layer is formed, and a photocurable sheet substrate on the surface of the light-transmitting sheet substrate. a semiconductor element having a light-receiving element mounted through a type insulating resin, the semiconductor element is face-down, and the extraction electrode formed on the element is in contact with the circuit conductor layer; At least a part of the circuit conductor layer on the translucent sheet substrate is connected to the circuit board, and the translucent sheet substrate is held by the circuit board.

[0005]

[Operation] In this way, with the above-described configuration of the present invention, it is possible to provide an image sensor that can be used with only a small amount of processing, regardless of whether it is a close-contact type or a completely close-contact type. Therefore, only one type of image sensor manufacturing equipment is required. Since it can be shared, capital investment can be reduced.

For example, in order to obtain a completely contact type image sensor, a semiconductor element having a light receiving element of a light-transmitting sheet substrate is placed face down on a surface different from the surface that contacts the circuit conductor layer, that is, the surface that contacts the original. For example, a photocurable transparent resin with excellent abrasion resistance, which serves as both a protective layer and an antistatic layer, or a layer made by dispersing a charge transfer medium, which is a low molecular compound, in a thermosetting or room temperature curing transparent resin, and then hardening the resin. By forming this, a fully contact image sensor with an excellent S/N ratio and high output uniformity can be easily obtained.

[0007] In addition, when obtaining a fully contact type image sensor using a glass substrate (fiber array plate) in which a fiber array is embedded, a completely contact type image sensor can be obtained by simply pasting the fiber part and the light receiving element so that they match. A sensor is obtained.

Furthermore, in order to obtain a close-contact type image sensor using a rod lens array, a close-contact type image sensor can be obtained simply by designing a chassis that can fix the document and the light-receiving element in a position that matches the focal position of the red lens. can get.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A one-dimensional image sensor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a front sectional view of an image sensor according to an embodiment of the present invention. 13 is an image sensor semiconductor element constituting a plurality of light receiving elements; 11 is a transparent sheet substrate used as a substrate for mounting the semiconductor element;
12 is a circuit conductor layer formed on the surface of the transparent sheet substrate 11; 14 is an electrode provided on the image sensor semiconductor element 13; and 15 is the image sensor semiconductor element 13 formed on the surface of the transparent sheet substrate 11. 17 is an image sensor semiconductor element 13;
This is a circuit board on which circuit components are mounted to hold a light receiving element provided in a semiconductor device, a 16 light-transmitting sheet substrate, etc., and a slit-like groove or hole is provided for a semiconductor element. 19 is a circuit conductor layer provided on the circuit board, and 18 is a transparent resin for fixing the translucent sheet board to the circuit board.

Next, a method of manufacturing the image sensor configured as described above will be explained. First, using a semiconductor process, a light receiving element 17 such as a phototransistor or photodiode and a CCD are formed on a single crystal silicon substrate (wafer).
A device equipped with an access circuit (not shown) such as MOS, bipolar IC, etc. is manufactured. In this embodiment, a light receiving element formed using a bipolar IC is used. The electrode 14 uses a two-layer Al wiring process and has a structure that protrudes from the wafer surface by about several μm using a sputtering method. Thereafter, this wafer is cut using high-precision dicing technology to produce image sensor semiconductor elements 13. Then polyarylate (PA), polyethersulfone (PES) or polyetheretherketone (PEE)
Forming a metal such as copper on a transparent sheet substrate 11 such as K) using a vapor deposition method, a sputtering method, a foil, etc.
A circuit conductor layer 12 is then formed by photolithography. A predetermined amount of acrylate-based transparent photocurable insulating resin 15 is applied to a predetermined position of the translucent sheet substrate 11 by a stamping method, a screen printing method, etc., and the image sensor semiconductor element 13 is placed on the electrode 14 in a predetermined position. circuit conductor layer 12
Place it face down so that it is in contact with the after that,
While applying pressure from above the image sensor semiconductor element 13, the transparent photocurable insulating resin 15 is irradiated with ultraviolet rays through the transparent sheet substrate 11 and cured, completing the mounting. This mounted translucent sheet substrate is bonded to the circuit conductor layer 19 to be connected of the circuit board 16 with a hole for the semiconductor element to be connected to the circuit conductor layer 12 on the translucent sheet substrate using thermocompression bonding, etc. Connect by soldering etc. Circuit components including a sensor drive circuit or a signal processing circuit may be mounted on this circuit board using multilayer wiring. Thereafter, in order to fix the translucent sheet substrate 11, a transparent photo-curing type, room temperature or thermosetting type silicone resin 18 or the like is injected and solidified to fix it to the circuit board.

As the transparent photocurable insulating resin 15, urethane acrylate-based or epoxy acrylate-based ultraviolet curable resins, which are cured by light irradiation, are suitable from the viewpoint of adhesiveness, photosensitivity, and electrical connectivity.

When producing the image sensor having the configuration shown in FIG. 1, a polyarylate film is used as the transparent sheet substrate 11, a copper foil of 8 to 17.5 μm is pasted thereon, and a circuit conductor is formed by photolithography. formed a layer. It is more preferable if the portion that contacts the sensor semiconductor element is plated with gold.

FIG. 2 is a front sectional view of a fully contact type image sensor according to a first embodiment of the present invention. 13 is an image sensor semiconductor element constituting a plurality of light receiving elements; 11
12 is a circuit conductor layer formed on the surface of the transparent sheet substrate 11; 14 is provided on the image sensor semiconductor element 13; Electrode 15 is a transparent photocurable insulating resin for mounting the image sensor semiconductor element 13 on the transparent sheet substrate 11; 20 is a material containing a charge transfer medium to electrically and mechanically protect the image sensor semiconductor element 13; 17 is a light-receiving element provided in the image sensor semiconductor element 13;
16 is a circuit board that holds a translucent sheet board, etc.; 18 is a silicone transparent resin for fixing to the circuit board; 19 is a chassis on the circuit board; It is a circuit conductor layer. Here, a read original, which is a detected object 22 disposed facing the light-receiving element, comes into contact with the light-receiving element through the protective layer 20.

Here, charge transfer media include heterocyclic compounds such as oxadiazole and oxazole, pyrazoline derivatives, triphenylmethane, hydrazone, triarylamine, N-phenylcarbazole, and stilbene, which are used in electrophotographic photoreceptors. Low molecular weight compounds are useful.

In this embodiment, a copper foil is bonded to a transparent sheet substrate 11 made of polyether sulfone (PES) with a roughened surface using an ultraviolet curable transparent insulating resin. Later, the circuit conductor layer 12 is formed by photolithography.
form. At this time, the copper foil portion removed by etching has a center line average roughness Ra=~0.5a and a maximum height Rm.
The surface is roughened to about ax=~1.2s. After mounting the image sensor semiconductor element 13, stilbene is applied to the light-curing transparent resin such as epoxy acrylate as a low-molecular compound charge transfer medium to the transparent sheet substrate 11 on the opposite side by, for example, screen printing. A well-dispersed solution with a weight ratio of 0.5 to 2, preferably 0.9 to 1.2, is applied and cured by UV irradiation to a thickness of 5 to 15 μm.
A protective layer 16 was formed. Finally, the chassis 21 is pressed and fixed to this protective layer to obtain a completely contact type image sensor.

Regarding this image sensor, an image sensor semiconductor element 13 is passed through a transparent sheet substrate 11, a transparent photocurable insulating resin 15, and a transparent silicone resin 18.
Light is projected onto the document 22 in contact with the protective layer 20 using an LED array or the like from above the nearby opening, and the light receiving element 17 detects the reflected light information and converts it into an electrical signal.

Since the fully contact type image sensor using the bipolar IC thus obtained has no effect on the output characteristics when the electric field strength due to tribo-electrification is 4 V/μm or less, the image sensor of this example is not affected by tribo-electrification. Although the charged potential was on the order of several tens of volts, there was no noise caused by the discharge, and the electric field strength was less than 1 V/μm, so the characteristics were not affected and stable output characteristics were obtained.

A second embodiment will be described with reference to FIG. 1st
Similar to the embodiment, the image sensor semiconductor element 13 is mounted face down on the circuit conductor layer 12 so that the electrode 14 is in contact with a predetermined circuit conductor layer 12, and after being fixed to the circuit board 16, Red lens array 23 and LED
An array 24 is arranged, and a read original 22 which is an object to be detected is placed.
and chassis 2 so that the light receiving element is located at the focal point of the lens.
1 was designed to obtain a contact type image sensor.

The image sensor of this example exhibited excellent characteristics, no different from conventional sensors obtained by wire bonding to conventional glass substrates or alumina substrates.

FIG. 4 shows a third embodiment of a complete contact type image sensor using a fiber array plate.

As in the first embodiment, after mounting the image sensor semiconductor element 13 on the circuit conductor layer 12 face down so that the electrode 14 is in contact with a predetermined circuit conductor layer 12, the circuit board 16 is mounted. Fixed to. Furthermore, after applying a transparent photocuring, heat or room temperature curing resin on the fiber array plate 25, a completely contact image sensor is obtained by arranging the light receiving element and the fiber array 26 so that they match and solidifying the resin. It is something that

The complete contact type image sensor of this embodiment has a relatively deep depth of focus, has little image deterioration due to static electricity due to friction or scratches due to wear, and has a simple manufacturing process, making it possible to provide an inexpensive fully contact type image sensor. .

[0024]

[Effects of the Invention] As described above, according to the present invention, the contact type,
Since it is possible to provide an image sensor that requires only a small amount of processing, regardless of whether it is a completely contact type, only one type of image sensor manufacturing equipment can be shared, reducing capital investment.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a one-dimensional image sensor in one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a fully contact type image sensor in a first embodiment of the present invention.

FIG. 3 is a sectional view of a contact type image sensor according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a complete contact type image sensor according to a third embodiment of the present invention.

[Explanation of symbols]

11 Translucent sheet substrate 12 Circuit conductor layer 13 Image sensor semiconductor device 14 Electrode 15 Transparent photocurable insulating resin 16 Circuit board 17 Photo receiving element 18 Transparent resin 19 Circuit conductor layer 20 Protective layer 21 Chassis 22 Detected object (scanned original) 23 Rod lens array 24 LED array 25 Fiber array plate 26 Fiber array

Claims (1)

[Claims] 1. A light-transmitting sheet substrate having a circuit conductor layer formed on its surface, and a semiconductor element having a light-receiving element mounted on the surface of the light-transmitting sheet substrate via a photocurable insulating resin. The semiconductor element is face-down and has a structure in which an extraction electrode formed on the element is in contact with the circuit conductor layer, and at least a part of the circuit conductor layer on the translucent sheet substrate is connected to the circuit board. A one-dimensional image sensor having a structure in which a translucent sheet substrate is connected to a circuit board and is held on a circuit board.