JP2008060476A - Solid state imaging apparatus, and electronic information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state imaging apparatus having high sensitivity and high resolution with no shading without using a color filter and an on-chip micro-lens, and to provide an electronic information apparatus, in which the solid state imaging apparatus as an image input apparatus is used in the imaging unit. <P>SOLUTION: Each solid-state imaging element having two light-receiving units 111, 112 laminated in the depth direction of a semiconductor substrate 101 is periodically arranged in a direction of substrate plane. Out of electromagnetic waves of the incident light, an electromagnetic wave of a wavelength region corresponding to the depth of each light-receiving unit is detected by each light-receiving unit 111, 112 through the wavelength dependence of an optical absorption factor in semiconductor substrate material, and the signal charge is generated so that isolation detection of the electromagnetic wave with wavelength different in each light-receiving unit 111, 112 can be carried out. Wiring layers 141-143 for transferring the signal charge from each light-receiving unit 111, 112 and transistors of a required number are arranged on the side opposite to the incidence side of the electromagnetic wave, so light is not kicked on the optical path because of these wiring layers 141-143, and it is not necessary to make light condensed at the light-receiving unit using an on-chip micro-lens. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device such as a CMOS type image sensor or a CCD type image sensor, and in particular, a system for separating and detecting light (electromagnetic waves) having different wavelengths by a plurality of light receiving units stacked in the depth direction of a semiconductor substrate. A solid-state imaging device, and a digital camera such as a digital video camera and a digital still camera using the solid-state imaging device as an image input device in an imaging unit, various image input cameras, scanners, facsimiles, camera-equipped mobile phone devices, etc. It relates to electronic information equipment.

  For example, in a conventional color solid-state imaging device represented by a CMOS type image sensor, a CCD type image sensor, etc., a plurality of light receiving units (a plurality of pixel units) that photoelectrically convert incident light to generate signal charges are arranged in a matrix. On the plurality of solid-state imaging devices, three or four types of color filters are arranged in a mosaic so as to correspond to the plurality of light receiving units, respectively. As a result, color signals corresponding to the color filter are output from each pixel unit, and color image data is generated by performing arithmetic processing on these color signals.

  However, in a conventional color solid-state imaging device in which color filters are arranged in a mosaic pattern, for example, when three primary color filters are used, about 2/3 of incident light is absorbed by the color filters. Therefore, since only about 1/3 of the remaining light is used for actually outputting the color signal, there is a problem that the light use efficiency is low and the sensitivity is low. Further, since only one color signal is obtained in each pixel portion, and the signals of the three primary colors are detected at different positions, there is a problem that the resolution is low and a false color problem is likely to occur.

  In order to solve these problems, for example, in Patent Document 1, a plurality of light receiving portions corresponding to the respective colors are stacked in the depth direction of the semiconductor substrate, and the wavelength dependence of the light absorption coefficient in silicon constituting the semiconductor substrate is shown. There has been proposed a solid-state imaging device of a type that performs color separation by detecting light in a wavelength region corresponding to the depth of each light receiving unit.

  The conventional solid-state imaging device of this system has, for example, a pixel section sectional structure in which photodiodes that generate signal charges for blue light, green light, and red light are sequentially stacked from the surface on the light incident side. According to this conventional solid-state imaging device, since color separation of each pixel is performed using the wavelength dependence of the light absorption coefficient in silicon, there is no need to provide a color filter, and most of the incident light is photoelectrically converted. Signal charge. Therefore, the light utilization efficiency is close to 100%, and the signals of the three primary colors can be obtained at the depth position of each pixel portion. Therefore, high sensitivity, high resolution, and no false color problem can be obtained. Image data can be generated. That is, in the past, four pixel portions (light receiving portions) corresponding to each color light of red (R), two green (G), and blue (B) were arranged in a planar shape, but R, G, B Since the light receiving portions corresponding to the three primary colors can be stacked vertically and used as one pixel portion, four times the resolution can be obtained. In addition, according to the conventional solid-state imaging device of this system, since it is not necessary to provide a color filter, the manufacturing process can be greatly simplified accordingly.

Next, in Patent Document 2, a MOS circuit unit is provided in a P-well layer, and each photoelectric conversion film corresponding to the three primary colors is vertically stacked with an organic semiconductor, and each photoelectric conversion film is irradiated with light from above. Is disclosed. In this case, the MOS circuit portion is provided below the photodiode. Also, in Patent Document 3, a multilayer wiring layer is formed on each photodiode arranged in a direction along the substrate surface, and light is transmitted to each photodiode from the back surface opposite to the multilayer wiring side. A back-illuminated solid-state imaging device for irradiating is disclosed.
US Pat. No. 5,965,875 JP 2005-303266 A JP 2005-150463 A

  However, the conventional solid-state imaging device disclosed in Patent Document 1 has the following problems.

  In the conventional solid-state imaging device disclosed in Patent Document 1, light is incident on a semiconductor substrate surface in a multilayer wiring layer required for transferring signal charges output from each pixel unit. It is provided on the same side as the side. For this reason, in the pixel array, the light receiving part becomes deeper as the wiring layer becomes multi-layered. In particular, light that is incident from an oblique direction can be lit on the optical path by these wiring layers. In order to prevent this, it is necessary to form an on-chip microlens on the wiring layer to efficiently collect light on the light receiving portion. Therefore, in the conventional solid-state imaging device disclosed in Patent Document 1, the former color filter formation among the color filter forming step and the on-chip microlens forming step as the manufacturing process related to the optical characteristics peculiar to the solid-state imaging device. Although the number of steps can be reduced, the latter on-chip microlens forming step cannot be reduced. Moreover, it is desirable that the semiconductor manufacturing apparatus can be diverted to manufacture other semiconductor devices. If a formation process unique to the solid-state imaging device (for example, an on-chip microlens formation process) remains, other semiconductor devices There is a problem in that it is inefficient in manufacturing a solid-state imaging device by the same line as the device. In addition, when another semiconductor device and a solid-state imaging device are mixedly mounted on the same chip module set, for example, if there is an on-chip microlens formation process, process consistency is poor and development difficulty becomes high. There is also a problem that it is not possible to increase the functionality of the solid-state imaging device.

  In addition, in the conventional solid-state imaging device disclosed in Patent Document 1, even when an on-chip microlens is provided, when the number of wiring layers is increased, the light collection rate is drastically lowered due to kicking of light on the optical path. Therefore, there is an upper limit for the number of wiring layers stacked. Actually, since the upper limit is 4 to 5 layers, a circuit that requires more multilayer wiring cannot be incorporated into the solid-state imaging device. Therefore, in the conventional solid-state imaging device disclosed in Patent Document 1, even if high sensitivity and high resolution are achieved without causing an increase in chip size, a high-functional image arithmetic processing circuit or the like is mixedly mounted. Therefore, downscaling cannot be realized for the entire chip module set.

  Furthermore, in the conventional solid-state imaging device disclosed in Patent Document 1, it is necessary to provide a wiring layer for transferring a signal charge output from each pixel unit between each pixel unit. The resolution of the solid-state imaging device is reduced by the area required for the arrangement. In particular, in a CMOS image sensor, in order to amplify the signal charge of each pixel unit or transfer the charge, it is necessary to arrange a plurality of types of transistors in the pixel array, so that the resolution is not reduced. The size of these transistors is required to be miniaturized as much as possible. However, with the miniaturization of a transistor, the structural variation related to the formation of the transistor increases, and as a result, the signal charge amplification characteristics due to the structural variation also fluctuate in each pixel portion, resulting in a problem that the image quality deteriorates. is there. This situation is also the same in the conventional solid-state imaging device disclosed in Patent Document 1, and the resolution is lowered or the image quality itself is deteriorated as the transistor characteristics in the pixel portion are required to be stabilized. The problem arises.

  Next, in Patent Document 2, although the MOS circuit portion is provided at a position below the photoelectric conversion film irradiated with light, the arrangement depth of the organic semiconductor photoelectric conversion film corresponding to the three primary colors is determined by each photoelectric conversion film. Are sandwiched between transparent electrode films, which are deeper than the photodiode that detects each color light at the depth position used in the present invention, and the incident light becomes oblique light in the peripheral part of the imaging region. An on-chip microlens is required because it needs to be focused well. Therefore, the problem similar to the problem by the patent document 1 as mentioned above arises.

  Further, in Patent Document 3, although a wiring layer is provided at a position below the photodiode to which light is irradiated, the arrangement depth of the photodiode in this case is set to form a color filter and an on-chip microlens. Since the planarization film is formed, it is deeper than the photodiode that detects light of each color at the depth position used in the present invention. Therefore, the incident light becomes oblique light in the peripheral part of the imaging region. Since it is necessary to collect light, an on-chip microlens is required. Therefore, the problem similar to the problem by the patent document 1 as mentioned above arises.

  The present invention solves the above-described conventional problems, and does not require a color filter and an on-chip microlens, and has a high sensitivity, a high resolution, and does not generate shading, and uses this solid state imaging device as an image input device. It is an object to provide an electronic information device used in a department.

  In the solid-state imaging device of the present invention, a plurality of solid-state imaging devices having a plurality of light receiving portions stacked in the depth direction of a semiconductor substrate are periodically arranged in a direction along the plane of the semiconductor substrate, and incident electromagnetic waves Of these solid-state imaging devices, signal charges are generated by detecting each electromagnetic wave in the wavelength region corresponding to the depth of each light receiving part due to the wavelength dependence of the light absorption coefficient of the semiconductor substrate material. Thus, each transfer path for transferring the signal charge from each light receiving portion is provided on one surface side of the semiconductor substrate, and the side opposite to the side on which the respective transfer paths are provided on the semiconductor substrate. The electromagnetic wave is configured to be incident on each light receiving portion from the other surface side of the substrate, whereby the above-described object is achieved.

  Preferably, in the solid-state imaging device according to the present invention, the semiconductor substrate is a silicon substrate having an epitaxial layer, and the light receiving portions are photodiodes formed by different types of semiconductor junctions.

  Further preferably, in the solid-state imaging device of the present invention, a circuit relating to selection of a specific solid-state imaging device from the plurality of solid-state imaging devices and signal output from the solid-state imaging device is provided in each of the solid-state imaging devices. The transistor constituting the circuit is provided from the side opposite to the light incident side of the semiconductor substrate.

  Further preferably, in the solid-state imaging device of the present invention, a circuit relating to selection of a specific solid-state imaging device from the plurality of solid-state imaging devices and signal output from the solid-state imaging device is provided in each of the solid-state imaging devices. The transistors constituting the circuit are provided on the impurity diffusion layer well and the impurity diffusion layer well constituting the light receiving portion.

  Further preferably, in the solid-state imaging device of the present invention, an amplification unit configured to amplify according to the signal voltage transferred from the light-receiving unit to the charge detection unit is configured in each of the solid-state imaging elements by the transistor. .

  Further preferably, in the solid-state imaging device according to the present invention, a selection unit that enables selection of the light-receiving unit by reading and controlling a signal amplified by the amplification unit in the solid-state imaging device, and the charge detection unit And a reset section for resetting the signal voltage to a predetermined voltage are respectively constituted by the transistors.

  Still preferably, in a solid-state imaging device according to the present invention, the signal charge transfer path is formed of a wiring layer.

  Further preferably, in the solid-state imaging device of the present invention, the light receiving portion and at least a part of the wiring layer are electrically connected by a contact portion provided in an interlayer insulating film between the light receiving portion and the wiring layer. Connected.

  Further preferably, in the solid-state imaging device according to the present invention, as the plurality of light receiving units, a first light receiving unit that detects an electromagnetic wave in a first wavelength range;... Nth (N is a natural number of 2 or more) wavelength range N light receiving parts for detecting the electromagnetic wave of the first and second light receiving parts.

  Further preferably, in the solid-state imaging device of the present invention, as the plurality of light receiving units, a first light receiving unit that detects an electromagnetic wave in a first wavelength region and a second light receiving unit that detects an electromagnetic wave in a second wavelength region are provided. Have.

  Further preferably, in the solid-state imaging device of the present invention, as the plurality of light receiving units, a first light receiving unit that detects an electromagnetic wave in a first wavelength range, a second light receiving unit that detects an electromagnetic wave in a second wavelength range, And a third light receiving unit for detecting electromagnetic waves in the third wavelength region.

  Further preferably, in the solid-state imaging device of the present invention, as the plurality of light receiving units, a first light receiving unit that detects an electromagnetic wave in a first wavelength range, a second light receiving unit that detects an electromagnetic wave in a second wavelength range, It has the 3rd light-receiving part which detects the electromagnetic wave of a 3rd wavelength range, and the 4th light-receiving part which detects the electromagnetic wave of a 4th wavelength range.

  Further preferably, in the solid-state imaging device according to the present invention, the depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is in the range of 0.2 μm to 2.0 μm as a depletion layer thickness. Infrared light is detected in a range of 5.0 μm ± 2.5 μm in depth from the light incident side surface of the semiconductor substrate to the second light receiving part.

  Further preferably, in the solid-state imaging device of the present invention, ultraviolet light is detected in a range from 0.1 μm to 0.2 μm in depth from the light incident side surface of the semiconductor substrate to the first light receiving part, White light is detected when the depth from the light incident side surface of the semiconductor substrate to the second light receiving portion is in the range of 0.2 μm to 2.0 μm as the depletion layer thickness.

  Further preferably, in the solid-state imaging device of the present invention, the depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is in a range of 0.1 μm to 0.4 μm, The depth from the light incident side surface to the second light receiving part is in the range of 0.4 μm to 0.8 μm, and the depth from the light incident side surface of the semiconductor substrate to the third light receiving part is 0. Three primary color lights are detected within a range of 8 μm to 2.5 μm.

  Further preferably, in the solid-state imaging device of the present invention, the depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is in a range of 0.1 μm to 0.4 μm, The depth from the light incident side surface to the second light receiving unit is in the range of 0.3 μm to 0.6 μm, and the depth from the light incident side surface of the semiconductor substrate to the third light receiving unit is 0. Detects primary color light and emerald color light within the range of 4 μm to 0.8 μm, and the depth from the light incident side surface of the semiconductor substrate to the fourth light receiving portion is within the range of 0.8 μm to 2.5 μm. To do.

  Further preferably, in the solid-state imaging device of the present invention, a light receiving unit set to a light receiving unit depth corresponding to the color light to be accurately expressed is added as a depth from the light incident side surface of the semiconductor substrate to the light receiving unit. .

  Still preferably, in a solid-state imaging device according to the present invention, the light incident side surface of the semiconductor substrate is polished to optimize the distance to each light receiving portion.

  Further preferably, in the solid-state imaging device of the present invention, element separation layers having a predetermined width for separating adjacent solid-state imaging elements from each other are provided in a lattice shape in plan view on the light incident side surface of the semiconductor substrate. Yes.

  Further preferably, in the solid-state imaging device of the present invention, an infrared cut filter is provided on the light incident side surface of the semiconductor substrate.

  Further preferably, in the solid-state imaging device of the present invention, a support substrate for increasing the strength is provided on the surface opposite to the light incident side surface of the semiconductor substrate.

  Further preferably, the support substrate in the solid-state imaging device of the present invention is a silicon substrate or a glass substrate. The support substrate may be a transparent silicon substrate or a transparent glass substrate. However, the support substrate does not need to be transparent, but rather is opaque because it can reduce the noise of the in-pixel transistor.

  Further preferably, in the solid-state imaging device of the present invention, the size of one side of the solid-state imaging element is in the range of 1.0 μm to 20.0 μm.

  Further preferably, in the solid-state imaging device of the present invention, the effective arrangement number of the solid-state imaging elements is in a range of 100,000 pixels to 50 million pixels.

  Further preferably, the solid-state imaging device of the present invention is a CMOS image sensor or a CCD image sensor.

  Furthermore, preferably, in the solid-state imaging device of the present invention, an extraction electrode to the outside is provided on the chip bottom surface side or the light incident side surface side of the semiconductor substrate.

  Further preferably, the light incident side surface of the semiconductor substrate in the solid-state imaging device of the present invention is polished to a distance to the shallowest light receiving portion.

  Further preferably, in the solid-state imaging device of the present invention, a planarizing film and an on-chip microlens thereon are not provided on the light incident side surface of the semiconductor substrate.

  Further, preferably, the light receiving unit in the solid-state imaging device of the present invention is configured with a flat surface.

  The electronic information device of the present invention is such that the solid-state imaging device of the present invention is provided in an imaging unit as an image input unit, and thereby the above-described object is achieved.

  The operation of the present invention will be described below with the above configuration.

  In the solid-state imaging device of the present invention, solid-state imaging elements having a plurality of light receiving portions stacked in the depth direction of the semiconductor substrate are periodically arranged in the plane direction of the substrate, and among the incident light (electromagnetic wave), Due to the wavelength dependence of the light absorption coefficient in the semiconductor substrate material, electromagnetic waves in the wavelength region corresponding to the depth of each light receiving part are detected at each light receiving part, and signal charges are generated. Light components (electromagnetic waves) having different wavelengths are separated and detected in the light receiving unit.

  In addition, since a transfer path (wiring layer) for transferring signal charges from the light receiving portion and a necessary number of transistors for assembling a predetermined circuit are provided on the surface opposite to the electromagnetic wave incident side, In this case, light is not kicked on the optical path by these wiring layers, and it is not necessary to form an on-chip microlens and collect light on the light receiving portion.

  Therefore, in the solid-state imaging device of the present invention, the color filter forming process and the on-chip microlens forming process as manufacturing processes related to the optical characteristics peculiar to the solid-state imaging device are reduced, and the solid-state imaging device is manufactured on the same line as other semiconductor devices. Therefore, even when another semiconductor device and a solid-state imaging device are mixedly mounted on the same chip module set, process consistency can be improved. In the solid-state imaging device of the present invention, the wiring layer is provided on the surface opposite to the electromagnetic wave incident side, and the light collection rate does not decrease due to the kicking of light on the optical path. It is possible to mount a high-performance image arithmetic processing circuit or the like. Furthermore, in the solid-state imaging device of the present invention, it is not necessary to provide a wiring layer for transferring signal charges output from each pixel unit (each light receiving unit) between the pixel units. The resolution of the imaging device does not decrease. If there is a wiring layer or a transistor on the side opposite to the light incident side to each light receiving section, the wiring layer width and the degree of freedom of arrangement of the wiring layer and transistor are greatly improved. In addition, in a CMOS image sensor, a transistor for amplifying or transferring a signal charge of each pixel is provided on the surface opposite to the electromagnetic wave incident side, so that the resolution is lowered depending on the arrangement area of the transistor. Rather, a sufficient size can be secured to stabilize the transistor characteristics.

  As described above, according to the present invention, it is possible to realize a solid-state imaging device that does not require a color filter and an on-chip microlens that are required in a conventional solid-state imaging device, and that has high sensitivity, high resolution, and does not generate shading. it can. In particular, when the present invention is applied to a CMOS type image sensor, it is not necessary to make a high degree of miniaturization in a transistor disposed in a pixel, and the signal charge transfer characteristics are stabilized to improve image quality while maintaining high resolution. Can be improved.

Hereinafter, Embodiments 1 to 6 of the solid-state imaging device of the present invention and the electronic information apparatus that uses any one of Embodiments 1 to 6 of the solid-state imaging device as an image input device in an imaging unit will be described as Embodiment 7. Details will be sequentially described with reference to the drawings.
(Embodiment 1)
In the first embodiment, as the plurality of light receiving units, a first light receiving unit that detects light (electromagnetic waves) in the first wavelength range and a second light receiving unit that detects light (electromagnetic waves) in the second wavelength range are provided. Will be described. In this case, the two colors having different wavelength ranges may be two colors such as infrared rays and visible light, and ultraviolet rays and visible light, as used in satellite photographs.

  FIG. 1 is a cross-sectional view illustrating a schematic configuration example of a solid-state imaging element provided in the solid-state imaging device according to Embodiment 1 of the present invention. In the solid-state imaging device according to the first embodiment, a plurality of unit pixel portions are periodically arranged in a two-dimensional matrix in a direction along the plane of the semiconductor substrate.

  In FIG. 1, a solid-state imaging device 100 according to the first embodiment includes a first light receiving unit 111 that detects an electromagnetic wave in a first wavelength range on a semiconductor substrate 101 as a solid-state imaging device as a unit pixel unit, and a second wavelength range. The second light receiving unit 112 that detects the electromagnetic wave is stacked in the depth direction of the semiconductor substrate 101.

  In the lower part of the semiconductor substrate 101, wiring layers 141 to 143 made of a metal material layer are provided. The wiring layers 141 to 143 are connected to each other to constitute a circuit relating to selection of a solid-state imaging device and signal output. Has been. In order to electrically connect these circuits to the first light receiving part 111 and the second light receiving part 112, contact parts 121 and 122 are provided, and a part of the wiring layer 141, the first light receiving part 111 and the second light receiving part are provided. The parts 112 are electrically connected to each other. The wiring layers 141 to 143 and the contact parts 121 and 122 are buried with interlayer insulating films 131 to 134 to form a three-layered wiring layer.

  With the above configuration, in the solid-state imaging device 100, during imaging, light is incident from the side where the first light receiving unit 111 and the second light receiving unit 112 of the semiconductor substrate 101 are formed. Of the incident electromagnetic wave (light), the electromagnetic wave in the wavelength range corresponding to the depth of each light receiving part is detected by each light receiving part due to the wavelength dependence of the light absorption coefficient in the semiconductor substrate material, and corresponds to each wavelength range Each signal charge is generated.

  Since the wiring layers 141 to 143 are provided on the surface opposite to the light incident surface of the semiconductor substrate 101, that is, on the back side of the first light receiving unit 111 and the second light receiving unit 112, the light from the wiring layers 141 to 143 is provided. There is no kicking of light on the road and no shading problems occur. This also eliminates the need to change the optical path, and thus eliminates the need to form on-chip microlenses.

  2A and 2B, in the solid-state imaging device 100A of the modification according to the first embodiment, the first light-receiving unit 111A and the second light-receiving unit 112A of the solid-state imaging element as the unit pixel unit are formed by different conductive semiconductor junctions. It is sectional drawing which shows an example comprised with the another photodiode.

  In FIG. 2, this solid-state imaging device 100A is provided with a second conductivity type impurity diffusion layer well 102 inside the first conductivity type semiconductor substrate 101A as a solid-state image sensor as a unit pixel unit, and further an impurity diffusion layer. A first conductivity type impurity diffusion layer well 103 is provided inside the well 102. A depletion layer is formed at each of the interface between the semiconductor substrate 101A and the impurity diffusion layer well 102, and at the interface between the impurity diffusion layer well 102 and the impurity diffusion layer well 103, and a photodiode with each PN junction is formed. When light is incident, it functions as a first light receiving unit 111A and a second light receiving unit 112A that respectively generate signal charges corresponding to light components having different wavelength ranges.

  Note that the semiconductor substrate 101A may be a silicon substrate having an epitaxial layer in part or in whole, and the photodiode may be formed in the epitaxial layer. In this case, the image quality can be improved by reducing the noise component of the signal charge.

  FIG. 3 shows an impurity diffusion layer well 103 in the solid-state image sensor, in the solid-state image sensor 100B according to the first embodiment of the present invention. It is sectional drawing which shows the structural example provided in FIG.

  In FIG. 3, in this solid-state imaging device 100 </ b> B, a transistor having a gate electrode 151, a drain diffusion region 152, and a source diffusion region 153 is provided in the impurity diffusion layer well 103 for each solid-state imaging device as a unit pixel unit. . The gate electrode 151 of the transistor is provided in the interlayer insulating film 131 between the light receiving portions 111A and 112A and the wiring layers 141 to 143. The drain diffusion region 152 and the source diffusion region 153 of the transistor are provided in the impurity diffusion layer well 103. Is provided. This transistor is connected to the wiring layers 141 to 143 by a drain contact portion 124 and a source contact portion 125 provided in the interlayer insulating film 131.

  Note that FIG. 3 shows an example in which the number of transistors provided on the impurity diffusion layer well 103 is one, but the present invention is also applied to a case where a plurality of transistors are provided. The present invention can also be applied to the case where the sizes and channel injection conditions of the plurality of transistors are different. When a plurality of transistors are arranged, the drain contact portion and the source contact portion may be shared by the plurality of transistors. Furthermore, the present invention can be applied to a case where the types and wirings of transistors provided in the respective impurity diffusion layer wells 103 are different in a plurality of adjacent solid-state imaging devices.

  FIG. 4 shows a specific configuration example of a circuit related to selection and signal output of a solid-state image sensor provided in the solid-state image sensor in the solid-state image sensor 100C of still another modified example according to the first embodiment of the present invention. FIG.

  In FIG. 4, the solid-state imaging device 100 </ b> C can reset the potential of the signal detection unit FD that detects the signal charge from the light receiving unit in the pixel array provided as the solid-state imaging device as the unit pixel unit (invalid Output from reset transistors R1 and R2 as reset units for discharging electric charges, amplification transistors A1 and A2 as amplification units that amplify according to the potential of signal detection unit FD, and amplification transistors A1 and A2, respectively. Each circuit having selection transistors S1 and S2 as selection units capable of reading out each signal to each signal line is connected to the first light receiving unit 111A and the second light receiving unit 112A, respectively. In short, a circuit including a reset transistor R1, an amplification transistor A1, and a selection transistor S1 is provided corresponding to the first light receiving unit 111A, and a signal charge is read from the first light receiving unit 111A to select and output a solid-state imaging device. I do. In addition, a circuit including a reset transistor R2, an amplification transistor A2, and a selection transistor S2 is provided corresponding to the second light receiving unit 112A, and a signal charge is read from the second light receiving unit 112A to select and output a solid-state imaging device. I do.

  With the above configuration, in the first light receiving unit 111A and the second light receiving unit 112A, the signal charges generated according to the wavelength ranges of the respective lights are read out to the respective signal detection units FD as two independent signals. Then, the signals are amplified by the amplification transistors A1 and A2, and read out to the signal lines Vout1 and Vout2 at predetermined timings by the selection signals Vselect1 and Vselect2 applied to the selection transistors A1 and A2, respectively.

  The gate potentials of the amplification transistors A1 and A2 (the potentials of the signal detection units FD) are reset applied to the reset transistors R1 and R2 before the next charge accumulation in the first light receiving unit 111A and the second light receiving unit 112A. Signals Vreset1 and Vreset2 reset power supply potentials Vdd1 and Vdd2 (Vdd2 may be equal to Vdd1), respectively. With this reset level as a reference, the signal charges generated in the first light receiving unit 111A and the second light receiving unit 112A corresponding to two different light wavelength ranges are amplified as two independent signals, respectively, and each gate potential is amplified. Read out to (the potential of each signal detection unit FD).

  Note that the circuit configuration example illustrated in FIG. 4 is not limited thereto, and various circuit configurations can be used as long as they have equivalent functions. For example, there may be a case where the selection transistors S1 and S2 are not provided. In addition, a circuit having an equivalent function may be configured so that a circuit for selecting a solid-state image sensor and outputting a signal is shared by a plurality of solid-state image sensors.

  Also, not only in a CMOS type image sensor, but also in the case where a signal charge is read out and transferred vertically to a vertical transfer unit like a CCD type image sensor, and further a signal detection unit performs signal detection via a horizontal transfer unit, It is only necessary that the vertical transfer unit and the horizontal transfer unit are provided on the side opposite to the light receiving surface side by applying the present invention.

Further, white light is detected when the depth from the light incident side surface of the semiconductor substrate 101A to the first light receiving portion 111A is in the range of 0.2 μm to 2.0 μm as the depletion layer thickness, and the light incident side surface of the semiconductor substrate 101A is detected. Infrared light may be detected within a depth of 5.0 μm ± 2.5 μm from the first light receiving unit 112A to the second light receiving unit 112A. In addition, ultraviolet light is detected in a range from the light incident side surface of the semiconductor substrate 101A to the first light receiving portion 111A in the range of 0.1 μm to 0.2 μm, and the second light reception is performed from the light incident side surface of the semiconductor substrate 101A. The white light may be detected when the depth to the portion 112A is in the range of 0.2 μm to 2.0 μm as the depletion layer thickness. Further, ultraviolet light is detected in a range where the depth from the light incident side surface of the semiconductor substrate 101A to the first light receiving portion 111A is 0.1 μm or more and 0.2 μm or less, and the second light reception is performed from the light incident side surface of the semiconductor substrate 101A. Infrared light may be detected when the depth to the portion 112A is in the range of 5.0 μm ± 2.5 μm. In this case, as the depth from the light incident side surface of the semiconductor substrate 101A to each light receiving portion, the light receiving portion set to the light receiving portion depth corresponding to the color light to be accurately expressed instead of the first light receiving portion 111A or 112A. May be added.
(Embodiment 2)
In the first embodiment, the case where the plurality of light receiving units includes the first light receiving unit that detects the electromagnetic wave in the first wavelength range and the second light receiving unit that detects the electromagnetic wave in the second wavelength range has been described. In the second embodiment, as a plurality of light receiving units, a first light receiving unit that detects electromagnetic waves in the first wavelength range, a second light receiving unit that detects electromagnetic waves in the second wavelength range, and electromagnetic waves in the third wavelength range are detected. The case where it has a 3rd light-receiving part is demonstrated. In this case, for example, three primary colors of R (red), G (green) and B (blue) are conceivable as three colors having different wavelength ranges of light.

  FIG. 5 is a cross-sectional view illustrating a schematic configuration example of a solid-state imaging element provided inside the solid-state imaging device according to Embodiment 2 of the present invention. In the solid-state imaging device according to the second embodiment, a plurality of unit pixel units are periodically arranged in a two-dimensional matrix in a direction along the plane of the semiconductor substrate.

  In FIG. 5, the solid-state imaging device 200 according to the second embodiment includes, as a solid-state imaging device as a unit pixel unit, a first light receiving unit 111 that detects an electromagnetic wave in a first wavelength range on a semiconductor substrate 201, and a second wavelength. A second light receiving unit 112 that detects electromagnetic waves in the region and a third light receiving unit 113 that detects electromagnetic waves in the third wavelength region are provided in a stacked manner in the depth direction of the semiconductor substrate 201.

  In the lower part of the semiconductor substrate 201, wiring layers 141 to 143 made of a metal material layer are provided, and these wiring layers 141 to 143 constitute a circuit relating to selection of a solid-state imaging device and signal output. In order to electrically connect these circuits to the first light receiving part 111, the second light receiving part 112, and the third light receiving part 113, contact parts 121 to 123 are provided, and a part of the wiring layer 141 and the first light receiving part are provided. The part 111, the second light receiving part 112 and the third light receiving part 113 are electrically connected. The wiring layers 141 to 143 and the contact parts 121 to 123 are buried with interlayer insulating films 131 to 134 to form a three-layered wiring layer.

  With the above configuration, in the solid-state imaging device 200, light is incident from the side on which the first light receiving unit 111 to the third light receiving unit 113 of the semiconductor substrate 201 are formed. Among the electromagnetic waves of incident light, electromagnetic waves in a wavelength region corresponding to the depth of each light receiving part are detected by each light receiving part 111 to 113 due to the wavelength dependence of the light absorption coefficient in the semiconductor substrate material, and signal charges are generated. Is done. For example, the first light receiving unit 111 detects blue light, the second light receiving unit 112 detects green light, and the third light receiving unit 113 detects red light.

  Since the wiring layers 141 to 143 are provided on the surface of the semiconductor substrate 201 opposite to the light incident surface, no light is kicked on the optical path by the wiring layers 141 to 143, and the problem of shading is Does not happen. Further, since there is no need to change the optical path, there is no need to form an on-chip microlens.

  FIG. 6 is a diagram showing a modification of the solid-state imaging device 200A according to the second embodiment of the present invention. In the solid-state imaging device, the first light receiving unit 111A, the second light receiving unit 112A, and the third light receiving unit 113A It is sectional drawing which shows the example comprised by the photodiode formed by (PN junction).

  In FIG. 6, this solid-state imaging device 200A is provided with a first conductive type impurity diffusion layer well 202 inside a second conductive type semiconductor substrate 201A as a solid-state imaging element as a unit pixel portion, and an impurity diffusion layer well. A second conductivity type impurity diffusion layer well 203 is provided inside 202, and a first conductivity type impurity diffusion layer well 204 is further provided inside the impurity diffusion layer well 203. Depletion layers are present at the interface between the semiconductor substrate 201A and the impurity diffusion layer well 202, the interface between the impurity diffusion layer well 202 and the impurity diffusion layer well 203, and the interface between the impurity diffusion layer well 203 and the impurity diffusion layer well 204, respectively. Each photodiode is formed and functions as a first light receiving unit 111A, a second light receiving unit 112A, and a third light receiving unit 113A that generate signal charges when light is incident thereon.

  The semiconductor substrate 201A may be a silicon substrate having an epitaxial layer in part or in whole, and the photodiode may be formed in the epitaxial layer. In that case, the image quality can be improved by reducing the noise component of the signal charge.

  The wavelength range detected by the first light receiving unit 111A is blue light, the wavelength range detected by the second light receiving unit 112A is green light, and the wavelength range detected by the third light receiving unit 113A is red light. All the color signals of the three primary colors of light can be detected by the respective light receiving portions 111A to 113A provided in the depth direction within one pixel portion.

  FIG. 7 shows the most modification of the solid-state imaging device according to the second embodiment of the invention for detecting all three primary color signals of light within one pixel by the first light receiving unit 111A to the third light receiving unit 113A. It is sectional drawing for demonstrating the specific example of an effective arrangement position.

  In FIG. 7, the solid-state imaging device 200 </ b> A includes a first light receiving unit 111 </ b> A that detects blue light inside a second conductive semiconductor substrate 201 </ b> A as a solid-state imaging device as a unit pixel unit. The second light receiving portion 112A, which is provided at a depth of 0.1 μm or more and 0.4 μm or less from the surface and detects green light, has a depth of 0.4 μm or more and 0.8 μm or less from the light incident side surface of the semiconductor substrate 201. The third light receiving portion 113A for detecting red light is provided at a position with a depth of 0.8 μm or more and 2.5 μm or less from the light incident side surface of the semiconductor substrate 201A. As described above, by arranging the first light receiving unit 111A to the third light receiving unit 113A, it is possible to more accurately detect all the color signals of the three primary colors of light within one pixel.

  The depth position of each light receiving unit is set to an optimum depth position depending on the detected wavelength region and the light absorption coefficient of the semiconductor substrate material, and the depth range is a general value. It is not limited to.

  FIG. 8 shows an impurity diffusion layer well 204 in a solid-state image sensor, in a solid-state image sensor 200B according to another modification of the second embodiment of the present invention. It is sectional drawing which shows the structural example provided in FIG.

  In FIG. 8, in this solid-state imaging device 200 </ b> B, a transistor having a gate electrode 151, a drain diffusion region 152, and a source diffusion region 153 is provided in the impurity diffusion layer well 204 for each solid-state imaging device as a unit pixel unit. . The gate electrode 151 of the transistor is provided in the interlayer insulating film 131 between the light receiving portions 111A to 113A and the wiring layers 141 to 143, and the drain diffusion region 152 and the source diffusion region 153 of the transistor are in the impurity diffusion layer well 204. Is provided. This transistor is electrically connected to the wiring layers 141 to 143 by a drain contact portion 124 and a source contact portion 125 provided in the interlayer insulating film 131.

  FIG. 8 shows an example in which the number of transistors provided in the impurity diffusion layer well 204 is one, but the present invention can also be applied to a case where a plurality of transistors are provided. The present invention is also applicable to the case where the sizes and channel injection conditions of the plurality of transistors are different. When a plurality of transistors are arranged, the drain contact portion and the source contact portion may be shared by the plurality of transistors. Furthermore, the present invention can also be applied to a case where the types and wirings of transistors provided in the respective impurity diffusion layer wells 204 in a plurality of adjacent solid-state imaging devices are different.

  FIG. 9 shows a specific configuration example of a circuit related to selection and signal output of a solid-state imaging device provided in the solid-state imaging device in a solid-state imaging device 200C of still another modified example according to Embodiment 2 of the present invention. FIG.

  In FIG. 9, the solid-state imaging device 200 </ b> C can reset the potential of the signal detection unit FD that detects the signal charge from the light receiving unit in the pixel array provided as the solid-state imaging device as the unit pixel unit (invalid Reset transistors R1, R2, and R3 as reset units for discharging electric charges, amplification transistors A1, A2, and A3 as amplification units that amplify according to the potential of the signal detection unit FD, and amplification transistors A1, A2 Each of the circuits having selection transistors S1, S2, and S3 as selection units that can read out the signals output from A3 and A3 to the signal lines Vout1 to Vout3, respectively. Each is connected to the unit 113A. In short, a circuit including a reset transistor R1, an amplification transistor A1, and a selection transistor S1 is provided corresponding to the first light receiving unit 111A, and a signal charge is read from the first light receiving unit 111A to select and output a solid-state imaging device. I do. In addition, a circuit including a reset transistor R2, an amplification transistor A2, and a selection transistor S2 is provided corresponding to the second light receiving unit 112A, and a signal charge is read from the second light receiving unit 112A to select and output a solid-state imaging device. I do. Further, a circuit including a reset transistor R3, an amplification transistor A3, and a selection transistor S3 is provided corresponding to the third light receiving unit 113A, and a signal charge is read from the third light receiving unit 113A to select and output a solid-state imaging device. I do.

  With the above configuration, in the first light receiving unit 111A, the second light receiving unit 112A, and the third light receiving unit 113A, the signal charges generated according to the wavelength ranges of the respective lights are converted into three independent signals as amplification transistors A1. , A2 and A3, and read out to the signal lines Vout1, Vout2 and Vout3 by selection signals Vselect1, Vselect2 and Vselect3 applied to the selection transistors A1, A2 and A3, respectively.

  The gate potentials of the amplification transistors A1, A2, and A3 (the potentials of the signal detection units FD) are reset signals that are applied to the reset transistors R1, R2, and R3 before the next charge accumulation in the first light receiving units 111A to 113A. Vreset1, Vreset2, and Vreset3 reset the potential of each signal detection unit FD to power supply potentials Vdd1, Vdd2, and Vdd3, respectively. Based on this reset, signal charges generated in the first light receiving unit 111A, the second light receiving unit 112A, and the third light receiving unit 113A corresponding to three different wavelength ranges are amplified as three independent signals. Read out to the signal lines Vout1, Vout2, and Vout3, respectively.

  Note that the circuit configuration illustrated in FIG. 9 is not limited thereto, and various circuit configurations are possible as long as they have equivalent functions. For example, the select transistors S1 to S3 may not be provided. In addition, a circuit having an equivalent function may be configured so that a circuit for selecting a solid-state image sensor and outputting a signal is shared by a plurality of solid-state image sensors.

As the depth from the light incident side surface of the semiconductor substrate 201A to each light receiving portion, in addition to the first light receiving portion 111A to the third light receiving portion 113A for detecting the three primary colors, the light receiving portion depth corresponding to the color light to be accurately expressed. It is also possible to add a light receiving unit set in this way.
(Embodiment 3)
In the first embodiment, the case where the plurality of light receiving units stacked vertically includes a first light receiving unit that detects electromagnetic waves in the first wavelength range and a second light receiving unit that detects electromagnetic waves in the second wavelength range will be described. However, in the third embodiment, as a plurality of light receiving units, a first light receiving unit that detects an electromagnetic wave in the first wavelength range, a second light receiving unit that detects an electromagnetic wave in the second wavelength range, and a third wavelength range The case where it has the 3rd light-receiving part which detects electromagnetic waves, and the 4th light-receiving part which detects the electromagnetic waves of a 4th wavelength range is demonstrated. The four colors in this case are, for example, the three primary colors R (red), G (green), and B (blue), and the color between G (green) and B (blue) is sensitive to the human eye, so emerald colors are used. May be added. For example, when a color near R (red) is to be emphasized accurately, a color near R (red) may be added. In addition, if you want to accurately express the skin color, sky blue, and water color, you can add a nearby color. To produce the skin color, a PN junction at a depth corresponding to the color between red and yellow. What is necessary is just to provide a part. In short, as the depth from the light incident side surface of the semiconductor substrate to the light receiving portion, a light receiving portion set to the light receiving portion depth corresponding to the color light to be accurately expressed may be added. This is not limited to the addition of one color, but a plurality of colors may be added. Here, in order to simplify the description, a case where an emerald color is added as one color will be described.

  FIG. 10 is a cross-sectional view illustrating a schematic configuration example of a solid-state imaging device provided inside the solid-state imaging device according to Embodiment 3 of the present invention. In the solid-state imaging device according to the third embodiment, a plurality of unit pixel units are periodically arranged in a two-dimensional matrix in a direction along the plane of the semiconductor substrate.

  In FIG. 10, the solid-state imaging device 300 according to the third embodiment includes, as a solid-state imaging device as a unit pixel unit, a first light receiving unit 111 that detects an electromagnetic wave in a first wavelength range on a semiconductor substrate 301, and a second wavelength. A second light receiving unit 112 that detects electromagnetic waves in the region, a third light receiving unit 113 that detects electromagnetic waves in the third wavelength region, and a fourth light receiving unit 114 that detects electromagnetic waves in the fourth wavelength region. Laminated in the depth direction.

  In the lower part of the semiconductor substrate 301, wiring layers 141 to 143 made of a metal material layer are provided, and these wiring layers 141 to 143 constitute a circuit relating to selection of a solid-state imaging device and signal output. In order to electrically connect these circuits to the first light receiving part 111, the second light receiving part 112, the third light receiving part 113, and the fourth light receiving part 114, contact parts 121 to 124 are provided, and the wiring layer 141 A part of the first light receiving unit 111, the second light receiving unit 112, the third light receiving unit 113, and the fourth light receiving unit 114 are electrically connected. The wiring layers 141 to 143 and the contact parts 121 to 124 are buried with interlayer insulating films 131 to 134 to form a three-layered wiring layer.

  With the above configuration, in the solid-state imaging device 300, light is incident from the side where the first light receiving unit 111 to the fourth light receiving unit 114 of the semiconductor substrate 301 are formed during imaging. Among the electromagnetic waves of incident light, electromagnetic waves in a wavelength region corresponding to the depth of each light receiving part are detected by each light receiving part 111 to 114 due to the wavelength dependence of the light absorption coefficient in the semiconductor substrate material, and signal charges are generated. Is done. For example, the first light receiving unit 111 detects blue light, the second light receiving unit 112 detects emerald light, the third light receiving unit 113 detects green light, and the fourth light receiving unit 114 detects red light. .

  Since the wiring layers 141 to 143 are provided on the surface of the semiconductor substrate 301 opposite to the light incident surface, no light is kicked on the optical path by the wiring layers 141 to 143, and the problem of shading is Does not happen. Further, since there is no need to change the optical path, there is no need to form an on-chip microlens.

  FIG. 11 shows a modification of the solid-state imaging device 300A according to the third embodiment of the present invention in which the first light receiving unit 111A, the second light receiving unit 112A, the third light receiving unit 113A, and the fourth light receiving unit 114A of the solid-state image sensor are connected to each other. It is sectional drawing which shows the example comprised by each photodiode formed by the semiconductor junction (PN junction) of a different conductivity type.

  In FIG. 11, a solid-state imaging device 300A includes a first-conductivity-type impurity diffusion layer well 302 provided inside a second-conductivity-type semiconductor substrate 301A as a solid-state image sensor serving as a unit pixel unit. A second conductivity type impurity diffusion layer well 303 is provided inside 302, a first conductivity type impurity diffusion layer well 304 is provided inside the impurity diffusion layer well 303, and a first conductivity type impurity diffusion layer well 304 is provided inside the impurity diffusion layer well 304. A two-conductivity type impurity diffusion layer well 305 is provided. The interface between the semiconductor substrate 301A and the impurity diffusion layer well 302, the interface between the impurity diffusion layer well 302 and the impurity diffusion layer well 303, the interface between the impurity diffusion layer well 303 and the impurity diffusion layer well 304, and the impurity diffusion layer well 304 A depletion layer is formed at each interface with the impurity diffusion layer well 305 to constitute each photodiode, and a first light receiving unit 111A and a second light receiving unit that generate signal charges when light is incident thereon. 112A, the third light receiving unit 113A, and the fourth light receiving unit 114A.

  The semiconductor substrate 201A may be a silicon substrate having an epitaxial layer in part or in whole, and the photodiode may be formed in the epitaxial layer. In that case, the image quality can be improved by reducing the noise component of the signal charge.

  The wavelength range detected by the first light receiving unit 111A is blue light, the wavelength range detected by the second light receiving unit 112A is emerald color light, and the wavelength range detected by the third light receiving unit 113A is green light. The wavelength range detected by the fourth light receiving unit 114A is red light, and all the four color signals of light are detected by each light receiving unit 111A to 114A provided in the depth direction within one pixel. Can do.

  FIG. 12 shows an impurity diffusion layer well 305 in the solid-state image sensor, in the solid-state image pickup device 300B according to another modification of the third embodiment of the present invention. It is sectional drawing which shows the structural example provided in FIG.

  In FIG. 12, in this solid-state imaging device 300 </ b> B, a transistor having a gate electrode 151, a drain diffusion region 152, and a source diffusion region 153 is provided in an impurity diffusion layer well 305 for each solid-state imaging device as a unit pixel unit. . The gate electrode 151 of the transistor is provided in the interlayer insulating film 131 between the light receiving portions 111A to 114A and the wiring layers 141 to 143, and the drain diffusion region 152 and the source diffusion region 153 of the transistor are in the impurity diffusion layer well 305. Is provided. This transistor is electrically connected to the wiring layers 141 to 143 by a drain contact portion 124 and a source contact portion 125 provided in the interlayer insulating film 131.

  FIG. 12 shows an example in which the number of transistors provided in the impurity diffusion layer well 305 is one, but the present invention can also be applied to a case where a plurality of transistors are provided. The present invention is also applicable to the case where the sizes and channel injection conditions of the plurality of transistors are different. When a plurality of transistors are arranged, the drain contact portion and the source contact portion may be shared by the plurality of transistors. Furthermore, the present invention can also be applied to the case where the types and wirings of the transistors provided in the respective impurity diffusion layer wells 305 are different in a plurality of adjacent solid-state imaging devices.

  FIG. 13 shows a specific configuration example of a circuit related to selection and signal output of a solid-state image sensor provided in the solid-state image sensor in a solid-state image sensor 300C of still another modified example according to Embodiment 3 of the present invention. FIG.

  In FIG. 13, the solid-state imaging device 300 </ b> C can reset the potential of the signal detection unit FD that detects a signal charge from the light-receiving unit in a pixel array provided as a solid-state imaging device as a unit pixel unit (invalid Reset transistors R1, R2, R3, and R4 as reset units for discharging charges, amplification transistors A1, A2, A3, and A4 as amplification units that amplify according to the potential of the signal detection unit FD, and amplification Each circuit having selection transistors S1, S2, S3, and S4 as selection units that can read out the signals output from the transistors A1, A2, A3, and A4 to the signal lines Vout1 to Vout4, respectively. The first light receiving unit 111A to the third light receiving unit 113A are connected to each other. In short, a circuit including a reset transistor R1, an amplification transistor A1, and a selection transistor S1 is provided corresponding to the first light receiving unit 111A, and a signal charge is read from the first light receiving unit 111A to select and output a solid-state imaging device. I do. In addition, a circuit including a reset transistor R2, an amplification transistor A2, and a selection transistor S2 is provided corresponding to the second light receiving unit 112A, and a signal charge is read from the second light receiving unit 112A to select and output a solid-state imaging device. I do. Further, a circuit including a reset transistor R3, an amplification transistor A3, and a selection transistor S3 is provided corresponding to the third light receiving unit 113A, and a signal charge is read from the third light receiving unit 113A to select and output a solid-state imaging device. I do. Further, a circuit including a reset transistor R4, an amplification transistor A4, and a selection transistor S4 is provided corresponding to the fourth light receiving unit 114A, and a signal charge is read from the fourth light receiving unit 114A to select and output a solid-state imaging device. I do.

  With the configuration described above, the signal charges generated in the first light receiving unit 111A, the second light receiving unit 112A, the third light receiving unit 113A, and the fourth light receiving unit 114A are amplified into four types of independent signals as amplification transistors A1, A2, and A2, respectively. Amplified by A3 and A4 and read out to signal lines Vout1, Vout2, Vselect3 and Vout4 by selection signals Vselect1, Vselect2, Vselect3 and Vselect4 applied to selection transistors A1, A2, A3 and A4, respectively.

  The gate potentials of the amplification transistors A1, A2, A3, and A4 (the potentials of the signal detection units FD) are reset by the reset transistors R1, R2, R3 before the charge accumulation in the first light receiving unit 111A to the fourth light receiving unit 114A. And the reset signals Vreset1, Vreset2, Vreset3 and Vreset4 applied to R4 reset the signal detectors FD to the power supply potentials Vdd1, Vdd2, Vdd3 and Vdd4, respectively. As a result, signal charges generated in the first light receiving unit 111A, the second light receiving unit 112A, the third light receiving unit 113A, and the fourth light receiving unit 114A corresponding to four different wavelength ranges are respectively converted into four independent signals. Data is read out to the signal lines Vout1, Vout2, Vout3, and Vout4, respectively.

  Note that the circuit configuration illustrated in FIG. 13 is not limited thereto, and various circuit configurations are possible as long as they have equivalent functions. For example, the select transistors S1 to S4 may not be provided. In addition, a circuit having an equivalent function may be configured so that a circuit for selecting a solid-state image sensor and outputting a signal is shared by a plurality of solid-state image sensors.

The depth from the light incident side surface of the semiconductor substrate 301A to the first light receiving portion 111A is in the range of 0.1 μm to 0.4 μm, and from the light incident side surface of the semiconductor substrate 301A to the second light receiving portion 112A. Is in the range of 0.3 μm to 0.6 μm, and the depth from the light incident side surface of the semiconductor substrate 301 to the third light receiving portion 113A is in the range of 0.4 μm to 0.8 μm. The three primary color light and the emerald color light are detected within a depth of 0.8 μm or more and 2.5 μm or less from the light incident side surface of the semiconductor substrate 301A to the fourth light receiving unit 114A. In this case, as the depth from the light incident side surface of the semiconductor substrate 301A to each light receiving part, instead of the second light receiving part 112A for detecting emerald light or in addition to the first light receiving part 111A to the fourth light receiving part 114 Thus, a light receiving unit set to a light receiving unit depth corresponding to the color light to be accurately expressed may be added.
(Embodiment 4)
14 is a cross-sectional view showing a configuration example in which an infrared cut filter is provided on the light incident surface side of the semiconductor substrate 201A of FIG. 6 in the solid-state imaging device according to Embodiment 4 of the present invention.

  As shown in FIG. 14, in the solid-state imaging device 400A of the fourth embodiment, by providing the infrared cut filter 161 on the light incident surface side of the semiconductor substrate 201A, noise generated in a deep region from the light incident surface is suppressed. Image quality can be improved.

  In this case, the light incident side surface of the semiconductor substrate 201A is polished so that the distances (depth positions) to the light receiving portions 111A to 113A are optimized. An infrared cut filter 161 is provided on the polished light incident side surface.

  Further, the light incident side surface of the semiconductor substrate 201A is polished to optimize the distance (depth position) to each of the light receiving portions 111A to 113A, and adjacent to the polished light incident side surface as shown in FIG. The element isolation layers 606 having a predetermined width for separating the solid-state imaging elements 603 to be separated from each other are provided in a lattice shape in plan view. An infrared cut filter 161 may be provided on this surface.

  In the solid-state imaging device according to the fourth embodiment, the method for suppressing noise generation due to the incidence of infrared light is not limited to this, and various methods can be used as long as they have equivalent functions. Can be realized. For example, a film that reflects only infrared light may be provided on the light incident surface of the semiconductor substrate.

In the fourth embodiment, the infrared cut filter 161 is provided on the light incident surface side of the semiconductor substrate 201 </ b> A in FIG. 6. The infrared cut filter 161 is provided in any of the solid-state imaging devices of the first to third embodiments. May be.
(Embodiment 5)
15 is a cross-sectional view illustrating a configuration example in which a support substrate for increasing the strength is provided on the surface opposite to the light incident surface of the semiconductor substrate 201A of FIG. 14 in the solid-state imaging device according to Embodiment 5 of the present invention. FIG.

  As shown in FIG. 15, in the solid-state imaging device 500 </ b> A according to the fifth embodiment, a support substrate 162 for increasing the strength is provided on the surface of the semiconductor substrate 201 opposite to the light incident surface. As a result, when manufacturing the solid-state imaging device 500A of the fifth embodiment, handling becomes easy and the difficulty of the manufacturing process can be reduced, and in particular, the wafer can be easily transported in the manufacturing line. Become. The material of the support substrate 162 may be, for example, silicon, silicon dioxide, or a glass substrate, and any material may be selected as long as it has an effect of increasing the strength of a very thin wafer. The support substrate 162 may be a transparent silicon substrate or a transparent glass substrate. However, the support substrate 162 does not need to be transparent. Rather, it is preferable that the support substrate 162 is opaque because noise in the pixel transistor can be reduced. .

In the fifth embodiment, the support substrate 162 for increasing the strength is provided on the surface opposite to the light incident surface of the semiconductor substrate 201A in FIG. 3 may be provided in any of the solid-state imaging devices.
(Embodiment 6)
FIG. 16 is a cross-sectional view for explaining a specific example of the size of the solid-state imaging device that is most effective in improving sensitivity and resolution in the solid-state imaging device according to Embodiment 6 of the present invention. Although the sixth embodiment will be described using the solid-state imaging device of FIG. 6, the present invention is not limited to this.

  In FIG. 16, in the solid-state imaging device 600A of Embodiment 6, when the light-receiving surface shape of the solid-state imaging device constituting the unit pixel unit is square in plan view, the length of one side is set to 1.0 μm or more and 20.0 μm. Set within the following range. By setting the element size within this range, the sensitivity and resolution of the solid-state imaging device can be most effectively improved by setting the length of one side of the solid-state imaging element.

  FIG. 17 is a plan view illustrating a schematic configuration example of a solid-state imaging apparatus according to Embodiment 6 of the present invention.

  In FIG. 17, the solid-state imaging device 600A according to the sixth embodiment is wired so that three row selection signal lines and reset signal lines 601 and three column image signal lines 602 intersect each other as a set. The solid-state image sensor 603 is periodically arranged at the intersection of the two, and the row selection signal line / reset signal line 601 and the column image signal line 602 are connected to the solid-state image sensor 603, respectively. The row selection signal line and reset signal line 601 are connected to a row selection scanning unit 604 provided at the left end of the substrate, and the column image signal line 602 is connected to an image signal output unit 605 provided at the lower end of the substrate.

  The solid-state imaging device 603 is disposed in the solid-state imaging device 600A within a range of 100,000 pixels to 50 million pixels. Thus, by setting the effective arrangement number of the solid-state imaging device 603, the sensitivity and resolution of the solid-state imaging device 600A can be most effectively improved.

In this case, as shown in FIG. 19, the imaging region is simply provided with element separation layers 606 having a predetermined width for separating adjacent solid-state imaging devices 603 from each other in a lattice shape in a plan view. There is no wiring layer around the image pickup element 603, and almost all of the image pickup region is a light receiving portion region, which ultimately becomes an efficient light receiving portion region.
(Embodiment 7)
FIG. 18 is a block diagram illustrating a schematic configuration example of an electronic information device using the solid-state imaging device according to any one of Embodiments 1 to 6 of the present invention as an imaging unit as Embodiment 7 of the present invention.

  In FIG. 18, the electronic information device 70 of the seventh embodiment includes, for example, a solid-state imaging device 200A according to any of the first to sixth embodiments, and predetermined signal processing for recording the color image signal from the solid-state imaging device 200A. And a memory unit 40 such as a recording medium that can record data after the liquid crystal, and a liquid crystal that can be displayed on a display screen such as a liquid crystal display screen after the color image signal from the solid-state imaging device 200A is subjected to predetermined signal processing for display. A display unit 50 such as a display device and a communication unit 60 such as a transmission / reception device that can perform communication processing after performing predetermined signal processing for color image signals from the solid-state imaging device 200A for communication.

  Examples of the electronic information device 70 include digital cameras such as digital video cameras and digital still cameras, image input cameras such as surveillance cameras, door phone cameras, in-vehicle cameras, and television telephone cameras, scanners, facsimiles, and mobile phones with cameras. An electronic apparatus having an image input device such as an apparatus is conceivable.

  Therefore, according to the seventh embodiment, based on the color image signal from the solid-state imaging device 200A, the image is displayed on the display screen, or the image is printed out on the paper by the image output device. This can be communicated favorably as communication data by wire or wirelessly, or can be stored favorably by performing predetermined data compression processing in the memory unit 40, or various data processing can be favorably performed.

  As described above, according to the first to sixth embodiments, the solid-state imaging devices having a plurality of light receiving portions stacked in the depth direction of the semiconductor substrate are periodically arranged in the substrate plane direction, and the incident light Of the electromagnetic waves, the wavelength dependence of the light absorption coefficient in the semiconductor substrate material detects the electromagnetic waves in the wavelength region corresponding to the depth of each light receiving part and generates signal charges, so no color filter is provided. However, it is possible to separate and detect electromagnetic waves having different wavelengths in each light receiving unit. Since the wiring layer for transferring signal charges from the light receiving unit and the required number of transistors are provided on the side opposite to the electromagnetic wave incident side, light is kicked on the optical path by these wiring layers in the pixel array. Therefore, there is no need to form an on-chip microlens and collect light on the light receiving portion. Accordingly, a solid-state imaging device that does not require a color filter and an on-chip microlens, has high sensitivity, high resolution, and does not generate shading can be obtained.

  In the first to third embodiments, two to four PN junctions are provided in the depth direction at a predetermined depth position of the semiconductor substrate in which two to four colors are matched to the light wavelength. Instead, a plurality of PN junctions may be provided in the depth direction at a predetermined depth position of the semiconductor substrate in which a plurality of colors are matched to the wavelength of light. From the viewpoint of color resolution, it is better to detect a large number of colors, but the number of manufacturing steps increases as the number of PN junctions increases.

  In the first to sixth embodiments, the configuration in which the three-layer metal wirings 141 to 143 are provided has been described as an example. However, the present invention also applies to a configuration in which multilayer wirings having different numbers of layers other than the three layers are provided. The present invention can also be applied to a configuration in which one layer of metal wiring is provided.

  Furthermore, in the first to sixth embodiments, the via contact portion that connects the plurality of wiring layers 141 to 143 is not shown. However, in order to form a circuit related to selection and signal output of the solid-state imaging device, the wiring layer 141 is used. It goes without saying that via contact portions for electrically connecting the wiring layers are formed between the respective layers .about.143.

  Furthermore, in Embodiments 1 to 6 described above, as an example, the lead-out part (contact part) for transferring the signal charge stored in the light-receiving part to the wiring layer is all provided on one side of the solid-state imaging device. As described above, the present invention can also be applied to the case where the arrangement location of the signal charge extraction portion is changed for each different wavelength range.

  Further, although not particularly described in the first to sixth embodiments, the lead-out electrode to the outside can be provided on the chip bottom surface side or the light incident side surface side of the semiconductor substrate.

  Further, although not particularly described in the first to sixth embodiments, the light incident side surface of the semiconductor substrate is polished and the distances to the respective light receiving portions are optimized. Polished to the distance to the shallow light receiving part. The distance to each light receiving unit is, for example, a depth of 0.1 μm or more and 0.4 μm or less from the light incident side surface in the first light receiving unit 111A, and 0.4 μm or more from the light incident side surface in the second light receiving unit 112A. The depth is 8 μm or less, and the depth is 0.8 μm or more and 2.5 μm or less from the light incident side surface in the third light receiving portion 112A. This is a flattening film on each light receiving portion, a color filter thereon, and The position of each light receiving portion is shallow compared to the prior art that provides the upper on-chip microlens. This also eliminates the need to provide a planarizing film and an on-chip microlens thereon on the light receiving portion. Therefore, in the present invention, the planarizing film and the on-chip microlens thereon are not provided on the light incident side surface of the semiconductor substrate. Needless to say, each light receiving portion is formed of a flat surface.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-7 of this invention, this invention should not be limited and limited to this Embodiment 1-7. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 7 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a solid-state image pickup device such as a CMOS image sensor or a CCD image sensor, and more particularly to a solid-state image pickup device that separates and detects electromagnetic waves having different wavelengths by a plurality of light receiving portions stacked in the depth direction of a semiconductor substrate. In addition, for example, digital cameras such as digital video cameras and digital still cameras using this solid-state imaging device as an image input device in an imaging unit, various image input cameras, scanners, facsimiles, electronic information devices such as camera-equipped mobile phone devices, etc. In the field, both the color filter and the on-chip microlens required in the conventional solid-state imaging device are unnecessary, and a solid-state imaging device with high sensitivity, high resolution, and no shading can be realized. In particular, when the present invention is applied to a CMOS type image sensor, it is not necessary to make a high degree of miniaturization in a transistor disposed in a pixel, and the signal charge transfer characteristics are stabilized to improve image quality while maintaining high resolution. Can be improved.

1 is a cross-sectional view illustrating a schematic configuration example of a solid-state imaging device provided in the solid-state imaging device according to Embodiment 1 of the present invention. In the solid-state imaging device according to the modification according to the first embodiment, an example in which the first light receiving unit and the second light receiving unit of the solid-state imaging element as the unit pixel unit are configured by photodiodes formed by different conductive semiconductor junctions. FIG. In the solid-state imaging device of another modification according to the first embodiment of the present invention, a configuration example in which transistors constituting a circuit relating to selection and signal output of a solid-state imaging device are provided in an impurity diffusion layer well in the solid-state imaging device. It is sectional drawing shown. FIG. 6 is a cross-sectional view illustrating a specific configuration example of a circuit related to selection and signal output of a solid-state imaging device provided in the solid-state imaging device in the solid-state imaging device of still another modified example according to the first embodiment of the present invention. is there. In the solid-state imaging device according to Embodiment 2 of the present invention, it is a cross-sectional view showing a schematic configuration example of a solid-state imaging device provided inside the device. In the solid-state imaging device of the modification according to the second embodiment of the present invention, the first light receiving unit, the second light receiving unit, and the third light receiving unit of the solid-state imaging device are configured by photodiodes formed by different conductive semiconductor junctions. FIG. In the solid-state imaging device of the above-described modification according to the second embodiment of the present invention, the most effective arrangement position for detecting all three primary color signals of light within one pixel by the first light receiving unit to the third light receiving unit. It is sectional drawing for demonstrating a specific example. In another solid-state imaging device according to the second embodiment of the present invention, a configuration example in which transistors constituting a circuit relating to selection and signal output of a solid-state imaging device are provided in an impurity diffusion layer well in the solid-state imaging device. It is sectional drawing shown. FIG. 9 is a cross-sectional view illustrating a specific configuration example of a circuit related to selection and signal output of a solid-state imaging device provided in the solid-state imaging device in a solid-state imaging device of still another modified example according to Embodiment 2 of the present invention. is there. In the solid-state imaging device according to Embodiment 3 of the present invention, it is a cross-sectional view showing a schematic configuration example of a solid-state imaging device provided in the device. In the solid-state imaging device according to the modified example of the third embodiment of the present invention, the first light receiving unit, the second light receiving unit, the third light receiving unit, and the fourth light receiving unit of the solid-state imaging device are formed by different conductive semiconductor junctions. It is sectional drawing which shows the example comprised by another photodiode. In a solid-state imaging device according to another modification according to Embodiment 3 of the present invention, a configuration example in which transistors constituting a circuit relating to selection and signal output of a solid-state imaging device are provided in an impurity diffusion layer well in the solid-state imaging device. It is sectional drawing shown. FIG. 9 is a cross-sectional view illustrating a specific configuration example of a circuit related to selection and signal output of a solid-state imaging device provided in the solid-state imaging device in a solid-state imaging device of still another modified example according to Embodiment 3 of the present invention. is there. 7 is a cross-sectional view illustrating a configuration example in which an infrared cut filter is provided on the light incident surface side of the semiconductor substrate of FIG. 6 in the solid-state imaging device according to Embodiment 4 of the present invention. FIG. 15 is a cross-sectional view illustrating a configuration example in which a support substrate for increasing the strength is provided on the surface opposite to the light incident surface of the semiconductor substrate in FIG. 14 in the solid-state imaging device according to Embodiment 5 of the present invention. In the solid-state imaging device concerning Embodiment 6 of this invention, it is sectional drawing for demonstrating the specific example of the magnitude | size of the solid-state imaging device most effective in improving a sensitivity and resolution. It is a top view which shows the schematic structural example of the solid-state imaging device which concerns on Embodiment 6 of this invention. It is a block diagram which shows schematic structural example of the electronic information device which used the solid-state imaging device in any one of Embodiments 1-6 of this invention for the imaging part as Embodiment 7 of this invention. It is the top view seen from the light-incidence side as a part of imaging region of the solid-state imaging device concerning Embodiment 6 of this invention.

Explanation of symbols

100, 100A, 100B, 100C, 200, 200A, 200B, 200C, 300, 300A, 300B, 300C, 400A, 500A, 600A Solid-state imaging device 101, 101A, 201, 201A, 301, 301A Semiconductor substrate 102, 103, 104 , 202, 203, 204, 302, 303, 304, 305 Impurity diffusion layer wells 111, 111A, 112, 112A, 113, 113A, 114, 114A Light receiving parts 121, 122, 123, 124 Wiring signal charges from the light receiving parts Contact part for transferring to the layer 124 Contact part (drain contact)
125 Contact part (source contact)
131, 132, 133, 134 Interlayer insulating films 141, 142, 143 Metal wiring layer 151 Transistor gate electrode 152 High concentration impurity diffusion layer (drain region)
153 High concentration impurity diffusion layer (source region)
161 Infrared cut filter 162 Support substrate 601 Row selection signal line and reset signal line 602 Column image signal line 603 Solid-state imaging device 604 Row selection scanning unit 605 Image signal output unit 606 Element separation layer 40 Memory unit 50 Display unit 60 Communication unit 70 Electronic Information equipment

Claims (30)

A plurality of solid-state imaging devices having a plurality of light-receiving portions stacked in the depth direction of the semiconductor substrate are periodically arranged in a direction along the plane of the semiconductor substrate, and among the incident electromagnetic waves, the light in the semiconductor substrate material A solid-state imaging device in which an electromagnetic wave in a wavelength region corresponding to the depth of each light receiving unit is detected by each light receiving unit due to the wavelength dependency of the absorption coefficient, and a signal charge is generated respectively.
Each transfer path for transferring a signal charge from each light receiving portion is provided on one surface side of the semiconductor substrate, and the other side of the semiconductor substrate opposite to the side on which each transfer path is provided A solid-state imaging device configured such that an electromagnetic wave is incident on each light receiving unit from the surface side.   2. The solid-state imaging device according to claim 1, wherein the semiconductor substrate is a silicon substrate having an epitaxial layer, and each of the light receiving portions is composed of photodiodes formed by different conductive semiconductor junctions.   Each of the solid-state imaging devices is provided with a circuit related to selection of a specific solid-state imaging device from the plurality of solid-state imaging devices and a signal output from the solid-state imaging device, and the transistors constituting the circuit are arranged on the semiconductor substrate. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is provided from a side opposite to the light incident side.   Each of the solid-state imaging devices is provided with a circuit related to selection of a specific solid-state imaging device from the plurality of solid-state imaging devices and signal output from the solid-state imaging device, and the transistors constituting the circuit are configured to receive the light receiving unit. The solid-state imaging device according to claim 1 or 2, wherein the solid-state imaging device is provided on the impurity diffusion layer well and the impurity diffusion layer well.   5. The solid-state imaging device according to claim 3, wherein an amplification unit that amplifies the solid-state imaging device according to a signal voltage transferred from the light-receiving unit to the charge detection unit is configured by the transistor.   A selection unit that enables selection of the light receiving unit by reading and controlling the signal amplified by the amplification unit in the solid-state imaging device, and a reset unit for resetting a signal voltage of the charge detection unit to a predetermined voltage The solid-state imaging device according to claim 5, wherein each is configured by the transistor.   The solid-state imaging device according to claim 1, wherein the signal charge transfer path is configured by a wiring layer.   8. The solid according to claim 7, wherein the light receiving portion and at least a part of the wiring layer are electrically connected by a contact portion provided in an interlayer insulating film between the light receiving portion and the wiring layer. Imaging device.   As the plurality of light receiving portions, N light receiving portions including a first light receiving portion that detects an electromagnetic wave in a first wavelength region and an Nth light receiving portion that detects an electromagnetic wave in an Nth (N is a natural number of 2 or more) wavelength region. The solid-state imaging device according to claim 1, comprising:   The solid-state imaging device according to claim 9, wherein the plurality of light receiving units include a first light receiving unit that detects an electromagnetic wave in a first wavelength region and a second light receiving unit that detects an electromagnetic wave in a second wavelength region.   As the plurality of light receiving parts, a first light receiving part for detecting electromagnetic waves in a first wavelength band, a second light receiving part for detecting electromagnetic waves in a second wavelength band, and a third light receiving part for detecting electromagnetic waves in a third wavelength band. The solid-state imaging device according to claim 9.   As the plurality of light receiving parts, a first light receiving part for detecting electromagnetic waves in a first wavelength band, a second light receiving part for detecting electromagnetic waves in a second wavelength band, and a third light receiving part for detecting electromagnetic waves in a third wavelength band. The solid-state imaging device according to claim 9, further comprising: a fourth light receiving unit that detects an electromagnetic wave in a fourth wavelength range.   The depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is within a range of 0.2 μm to 2.0 μm as a depletion layer thickness, and white light is detected from the light incident side surface of the semiconductor substrate. The solid-state imaging device according to claim 10, wherein infrared light is detected within a range of a depth of 5.0 μm ± 2.5 μm to the second light receiving unit.   Ultraviolet light is detected within a range from 0.1 μm to 0.2 μm in depth from the light incident side surface of the semiconductor substrate to the first light receiving unit, and the second light receiving unit is detected from the light incident side surface of the semiconductor substrate. The solid-state imaging device according to claim 10, wherein white light is detected in a range of up to 0.2 μm to 2.0 μm as a depletion layer thickness.   The depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is in the range of 0.1 μm to 0.4 μm, and the depth from the light incident side surface of the semiconductor substrate to the second light receiving portion. The depth is from 0.4 μm to 0.8 μm, and the depth from the light incident side surface of the semiconductor substrate to the third light receiving portion is from 0.8 μm to 2.5 μm. The solid-state imaging device according to claim 11 to be detected.   The depth from the light incident side surface of the semiconductor substrate to the first light receiving portion is in the range of 0.1 μm to 0.4 μm, and the depth from the light incident side surface of the semiconductor substrate to the second light receiving portion. The depth is from 0.3 μm to 0.6 μm, and the depth from the light incident side surface of the semiconductor substrate to the third light receiving portion is from 0.4 μm to 0.8 μm, The solid-state imaging device according to claim 12, wherein the three primary color light and the emerald color light are detected within a depth of 0.8 μm or more and 2.5 μm or less from a light incident side surface of the semiconductor substrate to the fourth light receiving unit.   The solid-state imaging according to any one of claims 13 to 16, wherein a light receiving part set to a light receiving part depth corresponding to color light to be accurately expressed is added as a depth from the light incident side surface of the semiconductor substrate to the light receiving part. apparatus.   18. The solid-state imaging device according to claim 1, wherein a light incident side surface of the semiconductor substrate is polished to optimize a distance to each light receiving unit.   18. The solid-state imaging device according to claim 1, wherein element separation layers having a predetermined width for separating adjacent solid-state imaging elements from each other are provided in a lattice shape in a plan view on a light incident side surface of the semiconductor substrate.   The solid-state imaging device according to claim 1, wherein an infrared cut filter is provided on a light incident side surface of the semiconductor substrate.   The solid-state imaging device according to claim 1, wherein a support substrate for increasing strength is provided on a surface opposite to the light incident side surface of the semiconductor substrate.   The solid-state imaging device according to claim 21, wherein the support substrate is a silicon substrate or a glass substrate.   The solid-state imaging device according to claim 1 or 19, wherein a size of one side of the solid-state imaging element is in a range of 1.0 µm to 20.0 µm.   The solid-state imaging device according to claim 1 or 23, wherein an effective arrangement number of the solid-state imaging elements is in a range of 100,000 pixels to 50 million pixels.   The solid-state imaging device according to claim 1, which is a CMOS type image sensor or a CCD type image sensor.   The solid-state imaging device according to claim 1, wherein an extraction electrode to the outside is provided on a chip bottom surface side or a light incident side surface side of the semiconductor substrate.   The solid-state imaging device according to claim 1 or 18, wherein the light incident side surface of the semiconductor substrate is polished to a distance to the shallowest light receiving portion.   28. The solid-state imaging device according to claim 1, wherein a planarizing film and an on-chip microlens thereon are not provided on the light incident side surface of the semiconductor substrate.   The solid-state imaging device according to any one of claims 1, 18 and 27, wherein the light receiving unit is configured by a flat surface.   An electronic information device in which the solid-state imaging device according to claim 1 is provided in an imaging unit as an image input unit.

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