JPH08111742A - Light source integrated type solid-state image pickup device - Google Patents

Abstract

PURPOSE: To obtain the light source integrated type solid-state image pickup device which can use a substrate for its solid state image pickup part irrelevant ly to whether the substrate is transparent or not, and is subminiature and in expensive. CONSTITUTION: This device is equipped with thin film light emitting elements 30 which are formed on both the sides of a sensor window 31 on the transparent substrate 21 and a solid image pickup element 10 which is formed on a substrate 1; and the transparent substrate 21 and substrate 1 are united together with a transparent adhesive 27, etc., so that the surfaces where the respective elements are arranged are brought into contact with each other and the sensor window 31 is above the solid image pickup element 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device integrated with a light source of an image sensor used in a facsimile or the like.

[0002]

2. Description of the Related Art In recent years, facsimiles have been required to be smaller, lighter, and cheaper in accordance with the spread thereof.
Image sensors used in facsimiles and the like are roughly classified into three types: non-contact type, contact type, and perfect contact type.

The non-contact type using a charge coupled device (CCD) has already been established, and L using a silicon wafer is used.
It is advantageous in terms of price because it can be produced by the SI manufacturing process and the CCD chip can be small, but since the original is projected on the CCD through the reduction lens system, there are two other methods for downsizing and weight reduction. Inferior to.

Further, the contact type image sensor has a merit that it is relatively easy to miniaturize since it does not need a reduction optical system and is gradually gaining acceptance in the market, but its rather high price hinders its popularization. It is in the state of being. Further, since the original is projected on the solid-state image pickup device using the SELFOC lens array and a light emitting diode (LED) array is used as a light source, a certain width and thickness are required (up to 15 mm).

On the other hand, the perfect contact image sensor can be further downsized as compared with the contact image sensor.
Since it is unnecessary to adjust the optical positions of the SELFOC lens array and the image sensor, the assembly process can be simplified easily. However, as in the contact image sensor, the thickness of the LED is still necessary. In addition, since the perfect contact image sensor needs to project light onto the original from the back side of the substrate on which the solid-state image sensor is arranged, it is necessary to form the solid-state image sensor on the transparent substrate, which is formed on the silicon wafer. It has been difficult to form a solid-state image sensor structure for a solid-state image sensor formed on a substrate that does not transmit light, such as a CCD or an alumina substrate.

A conventional example will be described below with reference to the drawings.
FIG. 7 is an explanatory view of a conventional example, and FIG. 7A is an explanation of a conventional contact image sensor. In FIG. 7A, the substrate 1 on which the LED house 42, the SELFOC lens array 43, and the solid-state image sensor are mounted is provided in the housing 41. Also, the LED installed in the LED house
Since it is a point light source, light is homogenized using a light diffusion plate such as frosted glass or a lens. Therefore, it is necessary to keep a distance from the document surface.

Such a contact-type image sensor is LE
The light emitted from the D house 42 is reflected by a document (not shown) on the housing 41, and the reflected light passes through the SELFOC lens array 43 and is input to the solid-state image sensor on the substrate 1.

This contact type image sensor is shown in FIG.
Some width and thickness is required, as indicated by the arrow at the bottom. FIG. 7B is a description of a conventional perfect contact image sensor, in which the solid-state image sensor 10 is provided on the upper surface of the housing 41.
Is provided with a substrate 1 on which a slit 40 for transmitting light is provided. An LED house 42 is provided on the lower surface of the housing 41. In this perfect contact type image sensor, the light emitted from the LED house passes through a slit 40 for transmitting the light provided on the substrate 1 and is reflected by a document (not shown), and the reflected light is reflected by the solid-state image sensor 10. It is input.

This perfect contact type image sensor is shown in FIG.
(B) The thickness of the LED house is required as indicated by the upper and lower arrows at the bottom.

[0010]

SUMMARY OF THE INVENTION The above-mentioned conventional devices have the following problems. Since the non-contact type image sensor projects the original document onto the CCD through the reduction lens system, the size and weight cannot be reduced. Further, since the contact type image sensor has an LED house as a light source, it cannot be downsized to a certain extent. Further, the perfect contact type image sensor needs to have a thickness corresponding to the LED house, and the solid-state image sensor needs to be formed on a transparent substrate.

As described above, it has been found that what limits the size of the image sensor is an optical system such as a lens or a light source. In other words, it is necessary to reduce the size of the optical system in order to further reduce the size of the image sensor. Further, these optical systems occupy a ratio equal to or higher than that of the solid-state image pickup device main body from the viewpoint of manufacturing cost, and it can be said that the cost reduction of the optical system is very important for lowering the price. In addition, if the solid-state image pickup device portion of the image sensor can be manufactured regardless of the type of substrate, the cost can be further reduced.

It is an object of the present invention to realize an ultra-compact and inexpensive solid-state image pickup device capable of manufacturing a solid-state image pickup device regardless of the type of a transparent or non-transparent substrate.

[0013]

FIG. 1 is a block diagram of the first embodiment of the present invention, and FIG. 6 is a block diagram of the second embodiment of the present invention.
The present invention has the following features to attain the object mentioned above.

(1) In FIG. 1, a solid-state image pickup device 10 and a read drive circuit 20 of the solid-state image pickup device 10 are formed on a substrate 1, and thin film light emitting devices 30 are formed on both sides of a sensor window 31 on a transparent substrate 21. To do. Next, the substrate 1 and the transparent substrate 21 are integrated by a transparent adhesive 27 or the like so that the surfaces on which the respective elements are arranged are aligned and the sensor window 31 is on the solid-state image sensor 10. Bonding or molding).

(2) Further, the thickness of the transparent substrate 21 is 5
It is set to 0 to 200 μm. (3) Further, as shown in FIG. 6, a SELFOC lens array 29 is provided on the document surface side.

[0016]

The operation of the present invention based on the above configuration will be described. The light emitted from the thin film light emitting device 30 of FIG.
The surface of the original 28 is illuminated from both sides of the sensor window 31 through 1. The reflected light from the original 28 is input to the solid-state image sensor 10 through the transparent substrate 21 and the sensor window 31. This input light is photoelectrically converted by the solid-state image sensor 10, and the photoelectrically converted output is input to the reading drive circuit 20. As a result, a signal corresponding to the grayscale image of the original 28 is obtained from the drive circuit 20.

Light emitted from the thin film light emitting device 30 shown in FIG. 6 is transmitted through the transparent substrate 21 and the SELFOC lens array 2.
Irradiate the surface of the original 28 through 9. The reflected light from the original 28 is reflected by the SELFOC lens array 29 and the transparent substrate 2.
1. Input to the solid-state image sensor 10 through the sensor window 31. This input light is photoelectrically converted by the solid-state imaging device 10, and a signal corresponding to a grayscale image of the original 28 is obtained.

As described above, since the solid-state image pickup device 10 and the thin film light emitting device 30 are formed of a thin film and integrated, the chip size can be made extremely small, and the thin film light emitting device 30 can be provided from both sides of the sensor window 31. Since the original can be uniformly illuminated, the wiring electrode of aluminum (Al) or the like of the thin film light emitting element 30 also serves as a light shield, so that stray light is significantly reduced and the circuit on the solid-state imaging element 10 side is illuminated. Can be protected from.

[0019]

【Example】

[Description of First Embodiment of the Present Invention] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a phototransistor, and FIGS.
FIG. 5 is an explanatory diagram of a solid-state imaging device forming process, and FIG.

FIG. 1 is a block diagram of the first embodiment.
1 will be described. A plurality of solid-state imaging devices 1 on the substrate 1
0 and the read drive circuit 20 of the solid-state image sensor 10, and the thin film light emitting elements 30 are formed on both sides of the slit-shaped sensor window 31 on the transparent substrate 21 which is thin film glass.
Next, the substrate 1 and the transparent substrate 21 are made to be transparent such as an epoxy adhesive or an ultraviolet curable adhesive so that the surfaces on which the elements are arranged are aligned and the sensor window 31 is on the solid-state image sensor 10. The adhesive 27 is used for adhesion. In this case, the original 28 to be read comes into contact with the transparent substrate 21.

FIG. 2 shows a photo used in the solid-state image sensor 10.
It is explanatory drawing of a transistor. In FIG. 2, 1 is a substrate
And, for example, glass substrate, quartz substrate, ceramics
(Al ₂O₃), Silicon substrate (polycrystal or single crystal), etc.
Is. 2 is an insulating film, and when the substrate 1 is a silicon substrate
If so, it can be formed using a thermal oxidation process. 3 is an active layer,
4 is a gate insulating film, 5 is a gate electrode, 6 is an interlayer insulating film,
7 is a metal wiring electrode, 8 is a so-called source / drain region
Is the impurity introduction part.

This phototransistor uses a thin film phototransistor which can be formed almost simultaneously with the process of manufacturing a thin film transistor (TFT). This thin film phototransistor serves as a photoelectric conversion element (solid-state image pickup element) of the solid-state image pickup device. In FIG. 2, the input light is input from the upper surface and photoelectrically converted in the active layer 3.

FIG. 3 is an explanatory view (1) of the forming process of the solid-state imaging device, and FIG. 4 is an explanatory view (2) of the forming process of the solid-state imaging device.
Is. Hereinafter, description will be given based on FIGS. 3 and 4. Board 1
For example, an inexpensive low-grade single crystal silicon substrate or a polycrystalline silicon substrate is used, and 300 n is obtained by thermal oxidation.
m thermal oxide silicon film is formed. The silicon oxide film thus formed may contain impurities depending on the grade of the silicon substrate 1 used. Therefore, a clean silicon oxide film of 200 nm is further formed by the low pressure vapor deposition (LPCVD) method to form the insulating film 2. Formed (see FIG. 3A).

Thereafter, as the active layer 3, a 200 nm-thick amorphous silicon film is formed by the plasma CVD method. The film forming conditions at this time were silane used as a reaction gas, a reaction temperature of 200 ° C., a gas pressure of 5.3 Pa,
By performing RF (high frequency) power of 35 W at a deposition rate of 6 nm / min, and further heating at 600 ° C. for 20 hours, amorphous silicon grows in a solid phase and becomes crystalline (FIG. 3).
(B)). An LPCVD method may be used instead of the plasma CVD method.

Polycrystalline silicon active layer 3 thus obtained
Is patterned into an island shape (see FIG. 3C). Subsequently, the polycrystalline silicon active layer 3 is thermally oxidized so that the gate silicon oxide film 4 becomes, for example, 100 nm (FIG. 3).
(D)).

Immediately after the formation of the silicon oxide film 4, L
Phosphorus (P) is used as the gate electrode 5 by the PCVD method.
N doped with about 10 ²⁰ atoms / cm ³ or more
⁺ Polysilicon (poly-Si) is deposited to a thickness of about 200 nm (see FIG. 3E).

Next, the gate electrode 5 is patterned by the dry etching method, and then the silicon oxide film 4 on the active layer 3 forming the contact layer is partially or entirely removed (see FIG. 3 (f)).

Impurities are introduced by ion implantation or ion doping to form an impurity introduction part 8. N
Phosphorus (P) is applied to the mold at an acceleration voltage of 60 KV 1 × 1
Implanting 0 ¹⁵ atoms / cm ² (see FIG. 4A).
Further, for the P type, a portion where the introduction of impurities is not desired is covered with a photoresist 9 and boron (B) is added to 40K.
After implanting a dose of 5 × 10 ¹⁵ atoms / cm ² with an accelerating voltage of V (see FIG. 4B), 600 ° C. in a nitrogen atmosphere to activate the introduced impurities.
Heat treatment is performed for 12 hours at the annealing temperature.

Next, a silicon oxide film or PSG (Phospho) is used as the interlayer insulating film 6 by the atmospheric pressure CVD method.
After forming a Silicate Glass film with a thickness of about 800 nm (see FIG. 4C), a contact hole is opened (see FIG. 4D), and aluminum (Al) 7 is formed with a sputtering method (see FIG. 4). (See (e)). After that, patterning is performed to provide Al wiring (see FIG. 4F). Finally, in order to improve electric characteristics, annealing treatment is performed in a hydrogen atmosphere at 350 ° C. for 1 hour. As a result, a desired solid-state imaging device, that is, the solid-state imaging device 10 and the reading drive circuit 20 are obtained.
Can be obtained at the same time.

FIG. 5 is an explanatory view of a process of forming a thin film light emitting device. In FIG. 5, the transparent substrate 21 has a thickness of 50 to
A 200 μm thin glass substrate is used. When the thickness of the transparent substrate is 200 μm or more, adjacent reflected light is mixed into the solid-state imaging device 10, resulting in poor resolution.
If the thickness is less than 50 μm, the strength of the substrate cannot be maintained. First, the transparent substrate 21 is washed (FIG. 5A).
reference).

Next, ITO (Indium Tin Oxide) to be the transparent electrode 22 is formed on the transparent substrate 21 (see FIG. 5).
(See (b)), and patterning this ITO film (see FIG. 5).
(See (c)), and the insulating film 23 is formed thereon. The insulating film 23 is SiO ₂ is a main component for example SOG (Sp
An in-on glass) film is formed (see FIG. 5D). At this time, hydrogenation treatment is performed as necessary to improve the characteristics of ITO (reduce resistance and improve light transparency).

Next, the insulating film 23 is patterned (see FIG. 5E), and the organic EL film 24 is mask-deposited by resistance heating (see FIG. 5F). This organic EL film 24
5F is composed of, for example, three layers of an electron transport layer 24-1, a hole transport layer 24-2, and a light emitting layer 24-3.

Further, a MgAg (magnesium-silver alloy) film 25 is vapor-deposited (see FIG. 5G), and then the wiring electrode 2 is formed.
As 6 is formed a film of Al by vapor deposition or sputtering (see FIG. 5 (h)).

The Al film is patterned to form the wiring electrode 26.
And two thin film light emitting (EL) elements 30 are formed. A sensor window 31 is provided between the thin film light emitting elements 30 (see FIG. 5 (i)).

Next, the thin film light emitting device 30 and FIG.
By adhering the solid-state image pickup device of 1) to the solid-state image pickup device of FIG. [Explanation of Second Embodiment] FIG. 6 is an explanatory view of the second embodiment, showing the configuration of a light source integrated type solid-state imaging device. In FIG. 6, the solid-state imaging device 10 and a drive circuit (not shown) are formed on the substrate 1, and the thin film light emitting device 3 is further provided on the transparent substrate 21.
0 is formed on both sides of the sensor window 31, and then the substrate 1 and the transparent substrate 21 are placed so that the surfaces on which the respective elements are arranged are aligned and the sensor window 31 is placed on the solid-state image sensor 10. It is adhered with a transparent adhesive 27, as shown in FIG.
Since the structure is the same as that shown in, it can be manufactured similarly.

In this case, the reading of the original 28 is performed via the SELFOC lens array 29. As a result, the depth of focus is increased by the SELFOC lens array 29, so that the transparent substrate 21 does not need to use thin film glass as in FIG. An ordinary glass substrate having a size of 200 μm or more can be used.

Therefore, the Selfoc lens array 29
However, an inexpensive substrate can be used as the transparent substrate 21. In the above description, the organic EL film has a three-layer structure including an electron transport layer, a hole transport layer, and a light emitting layer, but the present invention is not limited to this, and for example, an electron transport layer ( Light emitting layer) and a hole transport layer, or
A two-layer structure such as an electron transport layer and a hole transport layer (light emitting layer) may be used.

[0038]

As described above, the present invention has the following effects. (1) According to the invention described in claim 1, since the substrate of the solid-state imaging device section of the solid-state imaging device does not need to be transparent,
The solid-state imaging device can be manufactured regardless of the type of substrate, and the cost can be reduced.

Further, by integrating the transparent substrate on which the thin film light emitting element is formed with the substrate on which the solid state image pickup element is formed with a transparent body, it is possible to supply an ultra-compact and inexpensive light source integrated type solid state image pickup device. it can.

Further, since the MgAg film 25 and the wiring electrode 26 of the thin film light emitting element also serve as light shields, the circuit on the solid-state image pickup device side is protected from light and stray light to the solid-state image pickup device is protected without providing a light-shielding layer separately. Can be very small.

The thin film light emitting elements on both sides of the sensor window are
Unlike a point light source such as a light emitting diode, since it is a surface light source, a read original can be uniformly illuminated. (2) According to the invention described in claim 2, the transparent substrate 2
By setting the thickness of 1 to 50 to 200 μm, it is possible to obtain a perfect contact type.

(3) According to the invention described in claim 3, an inexpensive transparent substrate 21 which is not a thin film glass can be used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a phototransistor according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram (1) of a forming process of the solid-state image sensor according to the first embodiment of the present invention.

FIG. 4 is an explanatory view (2) of the forming process of the solid-state image sensor according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of the forming process of the thin film light emitting device according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram of a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 substrate 10 solid-state image sensor 20 reading drive circuit 21 transparent substrate 27 transparent adhesive 28 original document 30 thin film light emitting element 31 sensor window

Claims (3)

[Claims] 1. A thin film light emitting device formed on both sides of a sensor window on a transparent substrate (21), and a solid-state imaging device formed on a substrate (1), the surfaces on which the respective devices are arranged are aligned, and , The transparent substrate (2) so that the sensor window is on the solid-state image sensor.
A solid-state image pickup device integrated with a light source, characterized in that 1) and the substrate (1) are integrated by a transparent body. 2. The transparent substrate (21) has a thickness of 50-2.
The solid-state image pickup device with integrated light source according to claim 1, wherein the solid-state image pickup device has a diameter of 00 μm. 3. The light source-integrated solid-state image pickup device according to claim 1, wherein a SELFOC lens array is provided on the document surface side.