JPS58159059A - Image sensor - Google Patents

Abstract

PURPOSE:To constitute a one-dimensional image sensor which is capable of decreasing the number of electric connection lines outside, by constituting in one body a light source, a photoelectric converting device and a CCD device. CONSTITUTION:In front 2 of an image sensor, a lot of windows 1 are provided, and in the inside of the windows, a light emitting element 6 consisting of p-n junction and a photoelectric converting device 7 consisting of p-n junction are constituted. A luminous flux from the light emitting element 6 for emitting light by voltage impressed to electrodes 10, 11 irradiates an original 13 through an optical path 9, and its reflected light is made incident to the photoelectric converting device through an optical path 8. On the lower part of an earth plate 3 connected to the electrode 11 by a connection conductor 24 on the upper part of the window 1, a CCD device is constituted. A signal of each picture element detected by the photoelectric converting device 7 in the window 1 is shifted in order in this CCD device and is led out to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a one-dimensional image sensor that divides an image of a document into a plurality of pixels and sequentially transmits pixel signals corresponding to each pixel.

Such an image sensor has a plurality of pixel reading units arranged in a line, and is often used to read a document for transmission, for example, facsimile communication. Four solid-state image sensors have been known as this type of image sensor, but they require an electrical connection to the outside for each pixel reading section (usually there are several hundred sides), and require a large number of wiring lines, making it difficult to be flexible.・The purpose of the present invention v4 is to provide an image sensor that does not require electrical connection to the outside for each pixel reading section, and therefore has a small number of wires and is highly compatible with IM. What to do Kah.

Figures 1 to J show an image sensor according to an embodiment of the present invention.
This shows that. In FIG. 1, I is a plurality of nine windows provided on the front side of the image sensor. The front side 1 is formed in such a way that it can touch or approach the document to be read (FIG. 2, 1.y).

The window l is aligned in the direction of the first axis U on the front surface. An incident optical path [L A reflected optical path tb for guiding reflected light from the original, and a photoelectric conversion device provided at the end of the reflected optical path to receive the reflected light.In the present invention, each of the above components is formed using microfabrication technology. This is done by That is, a layer of amorphous silicon or an insulator is used to form a second substrate material to fill the etched portion of the first substrate material, thereby creating a three-dimensional external distribution of different materials. ,
To apply this process to the image sensor shown in the first WJK, substrate materials are stacked from bottom to top in the direction of the U axis and the X axis perpendicular to the V axis in the figure. As mentioned above, the image sensor of the present invention corresponds to one sub-scanning line,
It performs main scanning in the vertical or horizontal direction of the original 5iii, and an optical device is configured inside. These optical devices are composed of the above-mentioned light source, incident optical path 1, reflected optical path, photoelectric conversion, etc., and an electronic circuit device for controlling these is formed above the window 1 in FIG. In this case, the optical device is a pixel reading element distributed on an image sensor as described above. It is necessary to control light in each pixel reading element. Fig.
44/Fi is a device formed on these substrates by a conventional method, but the layer structure of the insulator on it is made of a single crystal substrate.
The usual method is to use tt, but these materials are transparent. The same can be said of the insulating material shown in Figure 6 (the same can be said of the insulating material of the mackerel).Furthermore, since the semiconductor part in the figure is an amorphous material, it is also transparent. When used in a structure, it is necessary to use an optically transparent material in the structure for growing an insulator in these methods.As a material that satisfies these conditions, synthetic resins such as alkyd resins are used. At the same time, it is necessary to consider chemical solvents for these materials, and K may be acetophenone, etc. This is used for alkyd resins as paints, adhesives, and plastics, and when a substrate is formed with these, it forms a liquid phase. Since it is in the form of a growth, it is possible to form a bulge at the interface between different materials due to side etching as shown in FIG. 3, or a groove that prevents the effect of a depression from propagating to the upper layer.

Acetophenone is used as a solvent for resins such as alkyd resins. Since 1N resin is an organic compound, it is not the same as a resist agent, and when removing the resist film, there is a risk that it may affect the substrate that has just been deposited, but resist removal is a method that uses a photosensitive column. Therefore, this risk can be ignored.

In the first step in forming the image sensor shown in FIG. 1, a resin substrate is formed below the window l. window l
The process of etching a layer in a plane parallel to the U-ma plane is described. FIG. 1 is a partial sectional view of the image sensor shown in FIG. In Figure 2, 6 is a book that constitutes a pn junction made of impurity semiconductors, and the minority current carriers moved by the voltage applied from both sides of 6 are p
This is a light-emitting element that emits light by bonding at the n-junction surface. /U and // are electrodes for applying the voltage and are made of conductors. The electrode 11 is connected to the earth plate J shown in FIG. 1 by taking care of the connection conductor.The part 1 is made of the light guiding material of the incident optical path ta and the reflected optical path tb. It shows the path of the light emitted from light f#6 reflected on the surface of the original 73 and scattered to the conversion device.

The optical If conversion device 7 constitutes a pn junction using an impurity semiconductor, and the bottom tome conversion device 7 lowered by the pn junction is connected to the ground electrode ti.

The light guide path S is made of a transparent material, whereas the portion in contact with it is made of an opaque material. FIG. 2 is a cross-sectional view of the pixel reading element structure shown in FIG. 1, which is the original drawing of the mask for resist film irradiation used for substrate formation and layering through the etching process as described above. Next K
, the electronic circuit section of the image sensor will be described.

FIG. 3(c)) is a diagram showing a partial tube above the position indicated by the dashed line in FIG. It is an extension of In the part shown with , 33 is S1
0. It is a film made of an insulating material such as, on which electrodes with a periodic structure are arranged. 29 is the part where the opaque insulator and conductor are intertwined, and the power supply or clock line is embedded therein. Figure 3(b) is.

In the cross-sectional view taken along the line 1b-1b in FIG. 3(a), the impurity semiconductor 3
In the portion 33 adjacent to 0, the electrodes iu, tt of FIG.
Connecting conductor #, an extension of 24I is provided.
The rest is made of opaque insulating material.
FIG. 4 schematically illustrates the xc-ic edge cross-section of FIG. 1L and the associated electrical connections. The periodic structure indicated by 1 is the impurity semiconductor region 30'f:CC in FIGS.
This is a charge transfer electrode when used as a D device, and a co-phase waveform for transfer is applied via wiring lines. - is 0 above
When a storage pulse is applied from wiring #-7, which is the storage electrode of the 0D device, the charge generated in the photoelectric conversion section 7 is drawn to the bottom of the insulating layer 33.

These charges are transferred in a shift register by known methods with co-phase waveforms applied to the charge transfer electrodes described above. 37 is the power supply line for the pixel light source, and is the conductor ? through the electrode t
vK*continued. 31 is a ground plate, which is connected to the electrode // through a conductor.

That's all for getting rid of F! In A, a method was described in which nine charges detected by each pixel reading element of an image sensor are transferred by a CCD device. Although this is an analog shift register, it is possible to transfer data using a slightly digital shift register. The method for making the CCI) device shown in Fig. 3 for the parts above the level + and II' in Fig. 1 is an application of the method for making the MO8 device shown in Fig. 6, and the amorphous semiconductor part in Fig. 3. By applying the device formation method shown in FIG. 6, it is possible to construct a digital shift register consisting of seven flops and one flop circuit. That is, these flip-flop circuits are formed one by one at a portion corresponding to 30 in FIG. 3(a), corresponding to the pixels of the image sensor.

The inputs of these flip-flop circuits are subjected to an etching process such that they are connected to the photoelectric conversion device 3.2 in FIG. There are two shift registers.

The processing for making the connection in this manner is performed on the portion corresponding to the part shown in FIG. 3 (LL).

In making integrated circuits, the process involves etching a film of material. To perform etching, an original plate called a mask is required to create a resist image. The mask works like a photographic plate, and is made by enlarging it to a size that is easy to draw, 70 times the size of the object to be processed, and then reducing it by obtaining a photograph from the nine original drawings. To carry out this process, a resist agent is first applied to the surface of the wafer to a uniform thickness, and after a hardening process, the resist is irradiated with light, electron beams, or generally radiation through a laser beam. Agents are materials whose solubility in specific chemical solvents changes when irradiated with radiation. A window corresponding to the pattern of a specific processing device is drawn on the mask using a well-known electron beam lithography method, etc. Zero-order K, radiation,
The electron beam transfer method changes the quality of the portion of the resist agent irradiated by the radiation that passes through the window of the mask, or by the electron beam. When performing a positive photo shoot, only the altered parts are dissolved away, creating a film pattern of resist agent on the sea urchin. Next, by dissolving or removing the wafer, the portions to which the resist agent is not attached are removed by a hot or dry etching process to form a planar fine pattern of the intended device. form part of a structure.

The present invention enables layered microstructures, and the necessary conditions for this are the formation of a second wafer to fill the area removed by etching of the first wafer as described above. It is necessary to be able to process Now, if another material is grown on the etched first wafer to form the material of the first wafer, the surface of this first material will be the same as the material of the first wafer. A depression is created in the area where it was removed. No. other than this Kuhomi.
The material in the area is removed. After this rounding, the following process is performed: Apply the resist agent again on the material of No. 1, and irradiate the resist agent on the second Kue 7S through the mask used when processing the first weno. A developing process is performed, which results in negative development. That is, portions of the resist agent that have not been irradiated and have not changed in quality are removed, and the material in the removed portions is etched. After that, the resist agent is removed. At this time, if a pattern opposite to that of the first Weno-K mask is used, a positive developing process is performed. That is, the resist agent in the part that has been irradiated and changed in quality is removed,
The material in that area is etched.

tsq Zusha This shows an example of forming a structure consisting of a three-dimensional distribution of one different material using the above method.A device 4'/ is formed on the surface of a semiconductor sea urchin using microfabrication technology. The surface is usually covered with a protective coating.
K-membrane convergence is formed. Figure (a) Fi shows this situation. 810 for Hoshu Agriculture If-! An oxide film such as Ml is used, but resin insulation can also be used.
4=An opening is formed in a desired portion of J by the above method. Thereafter, other materials are formed on the upper surface of the protective layer including the opening 17J, as shown in FIG. Next, as shown in FIG. 9(a), this material Sυ is removed by etching leaving only the opening formed in FIG. 9(1)). At this time, it is important to consider the combination of protective film erosion and material issues so that the protective film 1111#J is not etched at the same time as the material bowl.

Next, as shown in @Reference (・)K, the protective film 31 is applied to the surface again.
Forming Sui. Below 1. For this holding WkmJ/, Fig. q (
a) ~ (Repeat the same process as shown in the illusion to figure 1 (f)
) K A structure as shown can be obtained.

Each processed layer in the multilayer process shown in Figure 1 has its own thickness. This also causes side etching. In the figure, this side etching and side p-development are ignored. When side etching occurs, the processed layer/cut pattern is di-etched from the edge of the resist, and the finished dimension Lp becomes smaller than the resist dimension IJR. Figure 3 (a), (b)
1 shows this situation, where 33 is a resist, 3 is a processed layer, and ji is a substrate. Figure 5(a) is before etching.
Figure (b) shows the state after etching. The size of the side etch is expressed by the conversion difference LR-IJP, which increases in proportion to the thickness of the processed layer. Therefore, in the case of the process of the present invention, there is a possibility that an uplift force will occur at the seam of the material, the magnitude of which will depend on the magnitude of this side etching. The dimensions of the mask are determined by taking into account the size required to eliminate protuberances using these side etchings. Figure 3 (c), (+1)
, (e>) shows the results of the steps shown in Figures (b), (c) and (~) of surface side etching as described above and the resulting adjustment of the bulges that occur at the joints of the materials.Therefore, In reality, the interface of the structural frame shown in FIG. 9(f) is not as smooth as shown in the figure.This means that the dimensional accuracy of these three-dimensional structures is determined by the size of the side etching.

According to the above method, it is possible to create a three-dimensional distribution of several types of bud materials. The present invention makes it possible to construct a multilayer system in which a plurality of planes are stacked together using these methods, and is shown in Fig. Refer to Figure (f) - Electronic circuit denomination made by further laminating on the top surface using the Zozohoko (
It is possible to perform coupling with a chair system. If the material of the structure shown in FIG. 1(f) is optically conductive, optical coupling between the upper and lower layer systems is possible, and if it is electrically conductive, electrical coupling is possible.

Next, the distribution of p-type and n-type semiconductors is a liability for the internal structure of the device. For this reason, the methods shown in Figure 1 cannot be used as they are, but by modifying these methods depending on the material used, it is possible to create a three-dimensional distribution of pn&combination. First, when using a single-crystal semiconductor such as single-crystal silicon, the single-crystal semiconductor is grown in a vapor phase on a conductor substrate, and then an oxide group is grown in a vapor phase on top of that, and a resist film is applied on top of that. , particle beam irradiation is performed on the part to be made into an n-type semiconductor, the oxide film that is not irradiated is etched, and the n-type impurity is thermally diffused. The remaining oxide film is dissolved and an oxide film is grown again in a vapor phase over the entire surface.
This method, in which p-type diffusion is performed by performing a similar process on the portion to be used as a shadow region, lacks flexibility in terms of three-dimensional construction because the conductor substrate must be removed by etching, as will be described later. In order to provide flexibility in the construction method, the substrate may be an insulator. In this case, if an attempt is made to create a pn junction using the method described above, the semiconductor portion will be polycrystalline and impurities cannot be diffused. In order to create the required three-dimensional distribution of pn junctions by mixing impurities without using a single crystal, an amorphous semiconductor is used instead of a single crystal semiconductor. This is formed by direct current glow discharge decomposition, and PH, B, etc. are used as n-type impurities, and B, H, etc. are used as p-type impurities, and doping with these is done in the same way as in the case of single-crystal silicon. , SH, and PH, or h16.

FIG. 6 shows the method shown in FIG. 1 applied to the case of constructing a MOS device using a semiconductor such as amorphous silicon. Figure 6 (D) shows a semiconductor 6 containing p-type impurities on an insulator substrate 60 due to the above glow discharge.
The same figure (
b+ is obtained by etching the semiconductor 6/ of the same figure (a).

This is a dry etching method using resist, etc., and the etching gas is CF, 0? ,+O,,O
Use F, +N, etc. In the figure (0), oxide is vapor-phase grown on the entire surface of the figure (b) to form an insulating layer (LA4). In the same figure (((11), of the six insulating films, the portion on the semiconductor 41O is etched.

At this time, when the insulation fli4 is EIiO□, a gas different from that used when etching a semiconductor is used, such as ay gas as an etching gas. In the figure (e), an oxide film, etc., is grown in a vapor phase over the entire surface of the structure in the figure (cl), and in the figure (f), a p-type half is formed.
: To be established. Here, in the same figure (at 11O, MO
A portion of the insulator 63 above the p-type semiconductor 6) is etched to form an 8-device On-type semiconductor. Using the resist ybt used at this time as it is, as shown in the same figure (j), an n-type semiconductor 6S is grown by the same method as that for the p-type semiconductor, etched, and the resist film is removed. The processes shown in FIGS. 6(1) to 6(0) show the steps of forming a MOS device and its electrodes using an insulating film 66 and a conductive material 6.

Figure 6(p) shows the MO8 deno(chair) constructed in the above process, and 73.Kuda is its electrode as shown in Figure 6(0)K. For example, 7S is shown in Figure 19 (
The conductor shown in Figure 6 (p) is connected to the lower layer electronic circuit denomination (chair).
The process of making is not included in FIGS. 6(a) to (0). If the above electrode process is included, the same figure (&) ~ (0
), the number of processes will increase.

As described above, according to the present invention, it is not necessary to electrically connect each pixel reading element to the outside, and therefore it is possible to obtain a highly flexible image sensor with a small number of wiring lines.

Explanation of Drawing 0115 Figure 1 is a perspective view showing an image sensor according to an embodiment of the present invention, and Figure 2 is a perspective view of the image sensor of Figure 1. Cross-sectional view.

Figure 3 (turtle) is 1 in Figure 2. -1.1S cross-sectional view, Figure 3 ('b) is the Cao of Figure 3 (a), - Fengwa cross-sectional view, Figure 3 (
C) is 1. in Figure 3(a). -10 cross-sections and associated electrical connections; Figures (IL) to (f) are diagrams illustrating the process of forming a structure consisting of three-dimensional distribution of two different materials; 3(a) to 3(e) are diagrams showing the influence of side etching, and FIGS. 6(a) to 6(pl) are diagrams showing the process of forming the internal structure of the tenochise.

l...Window, C...Front, 6...Light emitting element, 7...
- Photoelectric conversion element, la...incident optical path, zab...reflection optical path, n, evaluation...connecting conductor, 30...integrated circuit.

Applicant's Representative: Boar Crotch Figure 4 42 Figure 5 Figure 6 1 Figure 6

Claims (1)

[Claims] a front surface provided with a plurality of windows formed to contact or approach the document to be read and aligned along the first axis IIK, a light emitting element, the first axis and the document surface KII! a plurality of incident optical paths extending along a first plane including a straight first axis and guiding light from the light emitting element to the window; and a plurality of reflective optical paths guiding reflected light from the original document to the window; a ninety-nine electric conversion element provided to receive the reflected light at an end of the reflected optical path; and the first of the photoelectric conversion elements.
The third point perpendicular to the plane of An image sensor comprising: an integrated circuit for signal processing formed at a position shifted in the direction of an axis; and a connecting conductor for connecting the light emitting element, the front light distribution electric conversion element, and the integrated circuit to wiring from the outside. -0