JP2524003B2 - Complete contact image sensor and unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perfect contact image sensor and a perfect contact image sensor unit for converting an optical image into an electric signal.

[0002]

2. Description of the Related Art Conventionally, in an image sensor, a semiconductor element 31 including a light receiving element 32 is fixed with a conductive adhesive on a substrate 30 on which conductor wiring is formed as shown in FIG. The layer 38 is connected to the layer 38 with a fine metal wire such as gold or aluminum by the wire bond method, and further, the layer 38 is sealed with a transparent glass sealing material.

In the image sensor unit using the conventional image sensor, the image sensor, the LED array 35 (light source) and the converging rod lens 34 have to be assembled and adjusted in the holders. .

[0004]

However, in the above-described structure, complicated steps such as wire bonding are required, and a converging rod lens is adjusted in position and incorporated into the image sensor in manufacturing the image sensor unit. There is a problem that it is necessary and the size increases due to the conjugate length of the lens.

[0005]

In order to solve the above problems, the present invention provides a semiconductor element having a light receiving element on a translucent substrate having a circuit conductor layer formed on the surface thereof through a photocurable insulating resin. Then, the image sensor is prepared by mounting the extraction electrode formed on the element face down so as to contact the circuit conductor layer. In the first aspect of the invention, the back surface of the translucent substrate, that is, the document contact surface , is received from the portion where the light receiving element faces, that is, the document surface.
A conductor layer is provided in a portion other than the portion through which the light entering the optical element passes .

A second invention is the back surface of the transparent substrate.
That is, the part where the light receiving element faces the original contact surface.
That is , a conductor layer is provided on a portion other than a portion through which light entering the light receiving element passes from the document surface, and a transparent insulating layer is further provided on the entire back surface.

According to a third aspect of the present invention, by using the perfect contact type image sensor, illumination is applied from the side of the transparent substrate on which the light receiving element is mounted, and the other surface is used as the original contact surface without a lens. A perfect contact image sensor unit capable of reading a document is created.

[0008]

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

FIGS. 1 (a) and 1 (b) are a front sectional view and a side sectional view of a perfect contact type image sensor in the embodiment of the first invention, and FIGS. 2 (a) and 2 (b) are shown. , Second
FIG. 3 is a front sectional view and a side sectional view of the perfect contact type image sensor in the embodiment of the invention of FIG. Reference numerals 1 and 11 are translucent substrates, 2 and 12 are circuit conductor layers formed on the surfaces of the translucent substrates 1 and 11, 3 and 13 are image sensor chips used as semiconductor elements, and 4 and 14 are image sensors. Electrodes 5 and 15 provided on the chips 3 and 13 are transparent photo-curable insulating resins for mounting the semiconductor image sensor chips 3 and 13 on the translucent substrates 1 and 11, and 6 and 16 are semiconductor image sensors. Protective layers for protecting the chips 3 and 13, 7 and 17 are light receiving elements provided in the semiconductor image sensor chips 3 and 13, and 18 are transparent substrates 1 and 1.
On the back surface (original contact surface) of 1 there is provided a conductor layer other than the portion where the light receiving elements 7 and 17 face each other (the portion through which light enters the light receiving element from the document surface), 19 is provided on the conductor layer 18. It is a transparent insulating layer provided.

A method of manufacturing the complete contact type image sensor having the above structure will be described. First, using a semiconductor process, a phototransistor or a photodiode such as a photodiode 7 or 17 is formed on a single crystal silicon substrate (wafer).
And an access circuit (not shown) such as a CCD, a MOS, or a bipolar IC. Each of the electrodes 4 and 14 has a structure in which it is projected from the wafer surface by about several μm by a sputtering method using a two-layer Al wiring process. After that, this wafer is cut by a high-precision dicing technique to make semiconductor image sensor chips 3 and 13. Next, a transparent substrate 1 having a thickness of 25 μm to 200 μm, such as polyarylate (PA), polyether sulfone (PES) or polyethylene terephthalate (PET).
A metal such as copper is deposited on the front surface and the back surface of 1 by a vapor deposition method, a sputtering method, a foil or the like to have a thickness of 3 μm to 20 μm.
m, and the circuit conductor layers 2 and 1 are formed later by photolithography.
2 and the conductor layers 8 and 18 are formed. Further, an acrylate-based photo-curable insulating resin is applied on the conductor layer 18 and irradiated with ultraviolet rays to form a transparent insulating layer 19 having a thickness of 5 μm to 20 μm. An acrylate-based transparent photocurable insulating resin 5 is provided at a predetermined position on the translucent substrates 1 and 11.
15 is applied by a predetermined amount by a stamping method or a screen printing method, and the semiconductor image sensor chips 3 and 13 are arranged face down so that the electrodes 4 and 14 contact the predetermined circuit conductor layers 2 and 12. Thereafter, while applying a predetermined pressure from above the semiconductor image sensor chips 3 and 13, the transparent photocurable insulating resins 5 and 15 are irradiated with ultraviolet rays through the transparent substrates 1 and 11 to be cured, and the mounting is completed. . Further, a resin such as transparent silicone is applied from above with a dispenser or the like to form the protective layers 6 and 16.

In this image sensor, the light receiving elements 7 and 17 detect optical information through the transparent substrates 1 and 11 and the transparent photocurable insulating resins 5 and 15, and convert the optical information into electric signals. There is.

As the transparent photo-curable insulating resins 5 and 15,
A urethane acrylate-based or epoxy acrylate-based ultraviolet curable resin is preferable in terms of adhesiveness and photosensitivity.

When the image sensor having the structure shown in FIGS. 1 and 2 is produced, a polyarylate film is used for the translucent substrates 1 and 11, and a copper foil is attached thereon, and the circuit conductor layer 2 is formed by a photolithography method. , 12 were formed.

Further, the conductor layers 8 and 18 and the transparent insulating layer 19
Is provided on the back surfaces of the transparent substrates 1 and 11, the electrostatic resistance and the abrasion resistance are dramatically improved.

FIG. 3 is a side sectional view of a perfect contact type image sensor unit according to the third embodiment of the present invention. Reference numeral 20 is a light source (LED array) for illuminating the original 29, 21 is a transparent substrate, 22 is a circuit conductor layer formed on the surface of the transparent substrate, 23 is an image sensor chip used as a semiconductor element, and 24 is Electrodes provided on the semiconductor image sensor chip 23, 25 is a transparent photo-curable insulating resin for mounting the semiconductor image sensor chip 23 on the translucent substrate 21, and 26 is transparent for protecting the semiconductor image sensor chip 23. A protective layer, 27 is a light receiving element provided on the semiconductor image sensor chip 23, 28 is a portion of the back surface (original contact surface) of the transparent substrate 11 where the light receiving element 27 faces (light entering the light receiving element from the document surface). Conductor layers provided other than the (portion through which) passes, and 29 is a document to be read.

In the perfect contact image sensor unit shown in FIG. 3, the conductor layer on the back surface of the transparent substrate of the perfect contact image sensor shown in FIG.
Transparent protective layer, transparent photo-curable insulating resin,
The original is illuminated through the window of the transparent substrate and the conductor layer, and the optical information from the original is directly guided to the light receiving element through the window of the conductor layer, the transparent substrate and the transparent photocurable insulating resin, This is for reading the information on the manuscript.

At this time, the thickness of the transparent substrate is 25 μm.
By using a thin polyarylate film of about 200 μm, it is possible to read optical information from a document with high resolution without crosstalk of light without a lens system (MTF value of 60).
% (4 lp / mm)), the size of the image sensor unit itself could be drastically reduced.
Further, by providing a conductive layer on the back surface of the light-transmitting substrate and grounding the conductive layer, it is possible to eliminate static electricity generated by rubbing of the original and reduce noise. Further, the light transfer efficiency is about 2 to 3 times higher than that of the conventional lens system, which contributes to the cost reduction of the light source (LED array).

The semiconductor image sensor chip used here was a bipolar IC chip using a phototransistor as a light receiving element and a scanning circuit using a thyristor shift register.

[0019]

As described above, according to the present invention, the wiring (wire bonding) operation of the semiconductor image sensor element by the fine metal wire is not performed, and the semiconductor element is not formed with the bump electrode and the circuit conductor layer is formed. It is possible to provide an inexpensive fully-contact image sensor that can be mounted with high reliability on a light-transmitting substrate provided with.

Further, in the image sensor unit of the present invention, a document can be read very simply, compactly and at low cost.

[Brief description of drawings]

FIG. 1A is a front cross-sectional view of a complete contact image sensor according to an embodiment of the first invention; FIG. 1B is a side cross-sectional view of a complete contact image sensor according to an embodiment of the first invention;

FIG. 2A is a front sectional view of a perfect contact image sensor according to an embodiment of the second invention, and FIG. 2B is a side sectional view of a perfect contact image sensor according to the embodiment of the second invention.

FIG. 3 is a front sectional view of a complete contact image sensor unit according to an embodiment of the third invention;

FIG. 4 is a configuration diagram of a conventional image sensor.

[Explanation of symbols]

 1 Translucent Substrate 2 Circuit Conductor Layer 3 Semiconductor Image Sensor Chip 4 Electrode 5 Transparent Light Curing Insulating Resin 6 Transparent Protective Layer 7 Light-Receiving Element 8 Conductor Layer 11 Translucent Substrate 12 Circuit Conductor Layer 13 Semiconductor Image Sensor Chip 14 Electrode 15 Transparent light curing type insulating resin 16 Transparent protective film 17 Light receiving element 18 Conductor layer 19 Transparent insulating layer 20 Light source (LED array) 21 Translucent substrate 22 Circuit conductor layer 23 Semiconductor image sensor chip 24 Electrode 25 Transparent light curing type insulating resin 26 Transparent protective layer 27 Light receiving element 28 Conductor layer 29 Original document 30 Substrate 31 Semiconductor image sensor chip 32 Light receiving element 33 Sealing glass 34 Focusing rod lens array 35 LED array 36 Original 37 holder 38 Circuit conductor layer 39 Electrode 40 Metal fine wire

Claims (3)

(57) [Claims] 1. A translucent substrate having a circuit conductor layer formed on a surface thereof, and a semiconductor element having a light receiving element mounted on the surface of the translucent substrate via a transparent photocurable insulating resin. the semiconductor device in a face-down, and a structure in which lead-out electrode formed on the element abuts on the circuit conductor layer on the back surface i.e. original contact surface of the transmissive substrate, said light receiving element face The part that is
A perfect contact type image sensor in which a conductor layer is provided in a part other than the part where the light entering the light receiving element passes . 2. A light-transmitting substrate having a circuit conductor layer formed on the surface thereof, and a semiconductor element having a light-receiving element mounted on the surface of the light-transmitting substrate via a transparent photocurable insulating resin. the semiconductor device in a face-down, and a structure in which lead-out electrode formed on the element abuts on the circuit conductor layer on the back surface i.e. original contact surface of the transmissive substrate, said light receiving element face The part that is
A complete contact type image sensor in which a conductor layer is provided in a portion other than the portion through which light entering the light receiving element passes, and a transparent insulating layer is provided on the entire back surface thereof . 3. The perfect contact image sensor according to claim 1, wherein a light source is attached to a side of the translucent substrate on which the semiconductor element is mounted at a position close to the semiconductor element, and the other surface of the translucent substrate is mounted. A complete contact image sensor unit with the original as the contact surface.