Photosensitive matrix array detector and process for making photosensitive detector - Patents.com

Abstract

The present invention relates to a photosensitive matrix array detector (20) organized into pixels (30) and a process for fabricating the detector, the detector comprising a planar substrate (22) having a plurality of interconnect levels connected to each other by through vias, a photodetector (24) grouping the pixels (30) of the photosensitive detector, the photodetector (24) being mounted on a first outer surface of the planar substrate (22) and configured to convert radiation sensed by the detector into an electrical signal through each of the pixels (30), and a semiconductor microcircuit (26) configured to drive and read out each of the pixels, the microcircuit (26) being mounted facing each of the pixels (30) or between adjacent pixels vertically to the substrate (22), each microcircuit (26) being supported by a microsubstrate (27) independent of the planar substrate (22) of the photosensitive detector, the microcircuit (26) being individually connected to one of the interconnect levels of the planar substrate (22).

Description

[Technical field]

[0001] The present invention relates to a photosensitive detector and a method for making the same. The present invention is particularly useful for making photosensitive detectors used to generate visible images. The invention is not limited to making this type of detector. The present invention may also be implemented to make detectors for producing pressure or temperature maps, or two-dimensional representations of chemical potential or electric potential. These maps or representations form an image of the physical quantity. [Background technology]

[0002] The invention may in particular be applied to the fabrication of active matrix detectors used, for example, for detection purposes in imaging devices employing ionising radiation, for example X-rays or gamma rays.

[0003] In a matrix detector, one pixel represents the basic sensitive element of the detector. Each pixel converts the physical phenomenon it receives into an electrical signal. The electrical signals coming from the various pixels are collected in a matrix readout stage and then digitized so that they can be processed and stored to form an image. A pixel is formed from a zone that is sensitive to a physical phenomenon, for example sending out a flow of charge. The physical phenomenon may be electromagnetic radiation carrying a photon flux, the invention will be explained below by this type of radiation, the charging current depending on the photon flux received by the sensitive zone. The general application to any kind of matrix detector is easy.

[0004] A matrix image detector comprises row conductors, each of which connects pixels of one and the same row, and column conductors, each of which connects pixels of one and the same column. The column conductors are connected to conversion circuits located at the edges of the matrix, sometimes commonly called "column bases". It goes without saying that the designations "row" and "column" are purely conventional and may be interchanged.

[0005] Each pixel generally comprises a photosensitive element or photodetector, which may be, for example, a photodiode, a photoresistor or a phototransistor. There is a large-scale photosensitive matrix, which may have millions of pixels organized in rows and columns. Each pixel further comprises an electronic circuit, which may further comprise other switches, capacitors, resistors, downstream of which the actuator is located. The assembly of photosensitive elements and electronic circuits makes it possible to generate electric signals and to collect them. The electronic circuit generally makes it possible to reset the signals collected at each pixel after the transfer, in order to read out the pixel. The role of the actuator is to transfer or copy the signals collected by the electronic circuit to the column conductors, based on the information received from the photosensitive elements. This transfer is carried out when the actuator receives an instruction to do so from the row conductors. The output of the actuator corresponds to the output of the pixel.

[0006] X-ray detectors are subject to size constraints. In fact, there are no easy means of deflecting this type of radiation. The detector must therefore have the size of the image that is to be produced. For example, in medical radiation, the detector may have a side length of more than 400 mm. It is not easy to make detectors with such dimensions.

[0007] Currently, there are two main families of X-ray matrix detectors. The first family uses materials such as silicon in the amorphous, polycrystalline or microcrystalline state. These materials are deposited in thin layers on a substrate, for example made of glass or polyimide. The second family uses monocrystalline materials. The second family makes it possible to achieve much better performances than the first family. On the other hand, the second family is limited in terms of dimensions due to the silicon substrates used. To make large detectors in the second family, it is necessary to join together several substrates on which the detector components are made.

[0008] Moreover, for both families of detectors, there can be a high reject rate during the manufacturing of the detector. Indeed, the higher the number of pixels, the higher the risk that at least one pixel will be defective. Image correction can make it possible to tolerate a few isolated defective pixels, but this remains an imperfect workaround.

[0009] One of the key parameters that leads to a high rejection rate is the complexity of the electronics associated with each pixel: in fact, the more complex the electronics, the higher the rejection rate. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to overcome all or some of the above problems by proposing a matrix photosensitive detector in which the electronic circuits providing at least the functions of driving and reading out each of the pixels are implemented separately, each on its own substrate, thereby making it possible to use substrates with different technologies for the electronic circuits and for the detector itself. The invention also makes it possible to test each electronic circuit individually before it is transferred to the substrate of the detector, which makes it possible to improve the reliability of the detector. [Means for solving the problem]

[0011] To this end, one subject of the invention is a matrix photosensitive detector organized into pixels, - a planar substrate having a plurality of interconnect levels connected to each other by through vias; - a photodetector arranged on a first outer surface of the planar substrate and grouping pixels of the photosensitive detector, the photodetector being configured to provide a conversion of radiation sensed by the detector by each of the pixels into an electrical signal; - a semiconductor microcircuit configured to drive and read out each of the pixels, the microcircuit being arranged facing each of the pixels or between adjacent pixels perpendicular to the substrate, each microcircuit being carried on a microsubstrate separate from the planar substrate of the photosensitive detector, the microcircuits being individually connected to the planar substrate at one of its interconnection levels.

[0012] Advantageously, the flat substrate has a second outer surface and connection pads arranged on the second outer surface and connected to the interconnect level, the microcircuit being arranged on the second outer surface and connected to the connection pads.

[0013] Advantageously, the planar substrate has connection pads arranged on a first external surface and connected to an interconnect level, each of the connection pads of the first external surface forming an individual electrode of one of the pixels.

[0014] The photodetectors may be in the form of a continuous layer disposed on the connection pads of the first exterior surface. Alternatively, the photodetectors are formed from individual photodetecting components each forming one of the pixels.

[0015] The light-detecting components may be embedded in the planar substrate.

[0016] The microcircuit may be disposed within a planar substrate.

[0017] The microcircuit may be common to several adjacent pixels.

[0018] Another subject of the invention is a method for making a photosensitive detector, comprising the steps of: - creating a planar substrate having a plurality of interconnect levels connected to each other by through vias; - fabricating semiconductor microcircuits configured to drive and read out each of the pixels, each on a microsubstrate separate from the planar substrate of the photosensitive detector; - transferring each microcircuit to a planar substrate by individually connecting it to one of the interconnection levels; This is a method that exists in

[0019] Advantageously, the method consists in testing the microcircuit before transferring it onto the planar substrate of the photosensitive detector.

[0020] The invention will be better understood and other advantages will become apparent on reading the detailed description of embodiments given by way of example, the illustration of which is illustrated by the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0021] [Figure 1] 2 shows a schematic diagram of multiple interconnect levels of a substrate of a photosensitive detector according to the present invention. [Figure 2a] 2 shows a first variant of the first embodiment of a photosensitive detector according to the invention; [Figure 2b] 2 shows a first variant of the first embodiment of a photosensitive detector according to the invention; [Figure 3a] 2 shows a second modified example of the first embodiment. [Figure 3b] 2 shows a second modified example of the first embodiment. [Figure 4a] 3 shows a variant of the second embodiment of the photosensitive detector according to the invention. [Figure 4b] 3 shows a variant of the second embodiment of the photosensitive detector according to the invention. [Figure 5a] 1 shows a variant in which the microcircuit is common to several adjacent pixels of the detector. [Figure 5b] 1 shows a variant in which the microcircuit is common to several adjacent pixels of the detector. [Figure 6a] 4 shows a variant in which a microcircuit is integrated into the substrate of a photosensitive detector according to the invention. [Figure 6b] 4 shows a variant in which a microcircuit is integrated into the substrate of a photosensitive detector according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] For purposes of clarity, identical elements have the same reference numbers in the various figures.

[0023] The present invention relates to a photosensitive matrix detector capable of detecting optical radiation reaching a detection zone. The photosensitive detector comprises a matrix of photosensitive elements or detection pixels distributed over the detection zone. Figure 1 shows in a schematic diagram a substrate 10 of a photosensitive detector according to the invention. The substrate 10 is in the form of a plate having at least the surface area of ​​the detection zone. The photosensitive elements are described below. The substrate fulfills two main functions: mechanical support and connection of the photosensitive elements. To provide the mechanical support function, the substrate 10 is made from a plate, for example glass, an organic material or any other material used to make printed circuit boards. Any other type of material may also be used within the scope of the invention. The material selected may for example allow the detector to be flexible. The photosensitive elements generally require at least two types of connections, one for driving and another for reading out the photosensitive elements. Other types of connections may also be used, such as for example a power supply. The photosensitive elements are therefore connected through the substrate to a driving module and a readout circuit, which may be located outside the detection zone. For example, if the shape of the detection zone is rectangular, the driving module may be located on one side of the rectangular shape and the readout circuitry may be located on the adjacent side. To provide the function of connecting the photosensitive elements, the substrate may then comprise row conductors for connecting the driving module to the photosensitive elements and column conductors for connecting the readout circuitry to the photosensitive elements. It goes without saying that the designations "row" and "column" are purely conventional and may be interchanged. In the substrate 10, the row conductors and the column conductors must cross each other without touching. To this end, the substrate 10 comprises two interconnection levels, one comprising the row conductors 12 and the other comprising the column conductors 14. The photosensitive elements are arranged on one of the faces of the substrate 10, and through vias 16 provide the connection between the conductors 12 and / or 14 and the photosensitive elements. In practice, the substrate 10 may comprise more than two interconnection levels, depending on the needs of the connection of the various photosensitive elements. The interconnection levels may be in the interior of the substrate 10 or may be arranged on the outer surface of the substrate 10.

[0024] The substrate 10 shown in Figure 1 only has a single row conductor and a single column conductor associated with each photosensitive element, although it is of course possible to have multiple row conductors and / or multiple column conductors associated with each photosensitive element.

[0025] 2a and 2b show a first variant of the first embodiment of the photosensitive detector 20 in a partial cross section in a plane perpendicular to the plane of the substrate. FIG. 2a shows three components of the detector 20 spaced apart from each other: the substrate 22 shown in FIG. 1, the photodetector 24 and the microcircuit 26 carried by a microsubstrate 27 independent of the substrate 22. Independent is understood to mean that they may be manufactured separately. The photodetector 24 is arranged facing a first side 22a of the substrate 22 and the microcircuit 26 is arranged facing a second side 22b of the substrate 22. The second side 22b is opposite the first side 22a. The three components of the detector 20 may be made separately and then assembled to form the photosensitive detector 20 as shown in FIG. 2b, the photodetector 24 being arranged on the side 22a and the microcircuit 26 being arranged on the side 22b.

[0026] The substrate 22 comprises a conductive pad 30 on its face 22a and a conductive pad 32 on its face 22b. The conductive pads 30 and 32 are connected to various interconnection levels not shown in Figures 2a and 2b. Only some vias 16 are shown by way of example. The interconnection levels may be arranged on internal layers or on the external faces 22a and 22b of the substrate 22. The microcircuit 26 is, for example, present on a microcircuit board 27 and is connected to the interconnection levels of the substrate 22 via pads 28 which abut against pads 32 of the substrate 22.

[0027] A single microcircuit 26 is shown in figures 2a and 2b, here common to two adjacent photosensitive elements and therefore connected to two pads 30. Alternatively, the microcircuit 26 may be associated with only one photosensitive element or with more than two photosensitive elements, four photosensitive elements as shown later with the help of figures 5a and 5b. The number of microcircuits is proportional to the number of photosensitive elements. The microcircuit comprises a semiconductor and is configured to at least drive and read out each of the photosensitive elements. As indicated in the introduction, the operation of the photosensitive elements generally requires at least one electronic switch to read out the photosensitive element by transferring the signal stored in the photodiode, for example in the form of a charge, to a column conductor when the electronic switch is closed. The switch is controlled by a row conductor. In the prior art, the switch and the photodiode are fabricated directly on the substrate using microelectronic techniques. Some photosensitive elements use more complex circuits, for example with three transistors. There is a transistor that performs the function of a readout switch, which is supplemented by a follower transistor that is placed between the photodiode and the readout transistor, along with a reset transistor for applying a fixed potential to the photodiode. To control the reset transistor, it is necessary to connect it to a specific row conductor. In the prior art, where the transistors are made directly on the substrate of the detector, it is almost impossible to make more complex control circuits, since the need to associate a circuit with each photodiode would present a reliability risk for detectors with millions of pixels. It is envisaged to make complex circuits, especially in detectors made with what is known as CMOS or IGZO technology. The CMOS-on-silicon technology uses metal oxide semiconductor field effect transistors by combining complementary n-type and p-type components. This technology is known by its acronym CMOS: complementary metal oxide semiconductor. The IGZO technology uses an indium-gallium-zinc oxide based semiconductor, and is known by its acronym IGZO: indium gallium zinc oxide.

[0028] The invention proposes to separate the photosensitive element itself, for example formed by a photodiode, photoconductor, etc., from the circuit associated with it, and to fabricate the circuit separately on its own substrate, independent of the detector substrate. This circuit is small, for example of the order of a few μm, and is therefore called a microcircuit. The size of the microcircuit should be considered in relation to the size of the detector itself. The detector substrate 22, for its part, may have a surface area close to that of the complete detector. In X-ray radiation applications, a conventional detector format is 430 mm x 430 mm. Since the microcircuits 26 are fabricated separately from the main detector substrate, they may be tested individually before being transferred to the substrate 22. Thus, only those microcircuits which have passed the individual test steps are transferred to the detector substrate. The increased reliability of the microcircuits makes it possible to envisage much more complex ones than the above-mentioned circuits with one or three transistors. In particular, it is possible to implement circuits integrating complex counting, digitization, etc. functions. Another advantage of fabricating the detector substrate and the microcircuit separately is that it allows the use of different manufacturing methods. For example, it is possible to produce microcircuits using high-performance semiconductor materials whose fabrication temperatures are significantly higher, typically in the range of 500-1000° C. As an example, the CMOS technology already mentioned above allows to fabricate complex and high-performance circuits, but requires fabrication temperatures higher than the limits that can be tolerated by substrates based on glass or organic materials.

[0029] In the embodiment shown in Figures 2a and 2b, the substrate 22 comprises conductive pads 30 on its face 22a, the surface of each of which forms the surface of a photosensitive element. More precisely, the pads 30 form the individual electrodes of each of the photosensitive elements. In other words, the detector comprises as many photosensitive elements as there are pads 30. The photosensitive detector 20 is a matrix detector organized into pixels. In this embodiment, the surface of each pad 30 forms the photosensitive surface of a pixel. The photodetector 24 groups the pixels of the photosensitive detector. The microcircuit 26 is arranged facing each of the pixels perpendicular to the substrate 22 and therefore facing these outer faces 22a and 22b. In practice, the substrate 22 may be flexible and may have a slight curvature. The perpendicularity is then defined locally at each pixel with respect to a plane tangent to the curvature of the substrate 22.

[0030] By placing the microcircuits 26 opposite each pixel, the connection lengths between the microcircuits 26 and the pixels can be minimized. This minimization makes it possible to reduce the electromagnetic sensitivity to disturbances coming from the environment. Moreover, only vias 16 that are perpendicular to the plane in which the substrate 22 mainly extends are advantageously used. The connections between the microcircuits 26 and the pixels are all identical for all pixels of the photodetector 24. Therefore, if electromagnetic disturbances disturb the connections, these disturbances are approximately identical for all pixels of the photodetector 24.

[0031] In practice, for detectors used in X-ray radiology, the photosensitive elements each have a square surface with a side length of, for example, the order of 50-200 μm depending on the envisaged application. The pads 30 therefore have this square shape and are spaced apart by 5-10 μm. In order to maximise the surface occupied by the photosensitive elements, it is advantageous to make the distance between the photosensitive elements as small as possible. This makes it possible to maximise the sensitivity of the detector 20. In this embodiment, it is advantageous not to use the outer surface 22a for wiring thereon row or column conductors between the pads 30. The row and column conductors are then routed on the surface 22b and in an internal layer of the substrate 22.

[0032] In the embodiment shown in figures 2a and 2b, the photodetector 24 comprises a layer that directly converts the incident radiation that it is desired to detect. In X-ray radiology, it is possible to use materials based on selenium, cadmium telluride (CdTe), materials from the perovskite family, etc., to bring about a direct conversion of X-ray photons into charges that are diffused on the electrodes formed by the pads 30. These materials may be deposited in the form of a layer 34 that covers the face 22a. The layer 34 may be continuous, if the lateral diffusion is sufficiently low, or pixelated. Depositing a continuous layer 34 has the advantage that it is not necessary to worry about the lateral positioning of the layer facing each of the pads 30. The layer 34 may be made directly on the substrate 22, if the method for depositing the layer 34 is compatible with the substrate 22, especially with regard to temperature. Alternatively, it is possible to make the layer 34 on a dedicated substrate 36 that forms the second electrode for the photodetector 24. The assembly formed by the substrate 36 and the layer 34 that forms the photodetector is then transferred to the substrate 22.

[0033] To facilitate the positioning of discontinuous layer photodetectors, i.e. photodetectors divided into pixels or groups of pixels, on substrate 22, it is possible to fabricate the discontinuous layers and electrodes forming the detection surface of each of the pixels on substrate 36. These electrodes are then contacted with pads 30 having a surface area smaller than that of the electrodes of the photodetectors. The smaller the pads 30, the greater the positioning tolerances.

[0034] In the first variant, the detection is called "direct". In other words, the incident radiation detected by the detector is directly converted into an electrical signal in the photodetector 24. The second variant, called "indirect" detection and shown in figures 3a and 3b, shows a photosensitive detector 40. There one can see the substrate 22 and the microcircuit 26, which is arranged facing the second side 22b of the substrate 22. The photodetector 24 from the first variant is replaced by a photodetector 44, which is formed from a scintillator 46 and a photodetection component, such as a photodiode 48. As in the first variant, figure 3a shows the substrate 22, the microcircuit 26 and the photodetector 44 spaced apart from each other. Figure 3b shows these same elements in an assembled state.

[0035] The incident radiation passes through the scintillator 46 and converts its photons into other photons in a wavelength band adapted to the photodiode 48. This second variant is well suited for the detection of X-rays, where the scintillator converts the X-ray photons into visible photons. Different materials may be used to make the scintillator, such as, for example, thallium-doped caesium iodide or gadolinium oxysulfide, known by the abbreviations GOS or GADDOX.

[0036] The light detection component is here a photodiode 48. Alternatively, any type of component capable of converting the photons emitted by the scintillator into an electrical signal can be used. Generally speaking, a photodiode comprises two electrodes separated by a photodetector layer capable of converting the photons it receives into an electrical signal. As mentioned above, one of the electrodes may be formed by a pad 30 belonging to the substrate 22. The photodiode 48 also comprises an electrode 50 and a photodetector layer 52. The electrode 50 is here transparent to the photons emitted by the scintillator 46. The electrode 50 is, for example, made of tin oxide, indium-tin oxide, etc. As this type of electrode may have a high resistivity, it is possible to add a metal mesh 54 to reduce the impedance of the surface of the electrode 50.

[0037] 3a shows a continuous electrode 50 and a photodetector layer 52. As in the first variant, it is possible to make the electrode 50 and the photodetector layer 52 discontinuously, i.e. divided into pixels or groups of pixels. As mentioned above, in the case of a discontinuous layer, the electrode 30 may be made directly on the photodetector layer 52. The assembly formed by the scintillator 46 and the photodiode 48, comprising these two electrodes 30 and 50, is attached to a pad on the face 22a of the substrate 22.

[0038] 3b shows the substrate 22, the microcircuit 26 and the photodetector 44 in an assembled state. In addition to the circuitry for driving and reading out the pixel associated with it, the microcircuit 26 may optionally comprise a light-emitting diode 56 for emitting a flash of light in the direction of the photodiode 48 to saturate it. This type of illumination may be performed after the photodiode 48 has been read out to avoid any residual magnetism. If a light-emitting diode 56 is used, the electrode 30 and the substrate 22 are at least partially transparent to the optical radiation emitted by the light-emitting diode 56. Other components, such as, for example, thermal or mechanical sensors, may also be transferred in addition to or instead of the light-emitting diode 56.

[0039] Further optionally, the detector 40 may comprise a second scintillator 58 covering the microcircuit 26 over the entire detection surface of the detector 40. The scintillator 58 makes it possible to recover the X-ray photons not converted in the scintillator 46 in order to return their energy in the form of visible photons to the photodiode 48, thus improving the sensitivity of the detector or making it possible to produce images in a dual energy mode.

[0040] 4a and 4b show two variants of the second embodiment of the photosensitive detector according to the invention. In these two variants, the microcircuit is arranged in a substrate. More precisely, the microcircuits, each fabricated on a separate substrate, are transferred to the substrate of the detector.

[0041] FIG. 4a shows in cross section a detector 60 comprising a substrate 62, a photodetector 64 and a number of microcircuits 66, one of which is shown in FIG. 4a. The substrate 62 comprises, for example, two interconnect levels 68 and 70 connected by vias 72, one of which is shown in FIG. 4a. The interconnect levels 68 and 70 are embedded in a dielectric material that is partially perforated to expose pads 74 at the interconnect level 68. The pads 72 perform the same function as the pads 30 shown in FIGS. 2a and 2b. The photodetector 64 abuts the pads 74. The surface of each pad 74 forms the light-sensitive surface of a pixel. The microcircuits 66 are arranged between two adjacent pixels.

[0042] FIG. 4b shows in cross section a detector 80 in which the substrate 62 and its two interconnection levels 68 and 70 are connected by vias 72. Pads 74 are located on the interconnection level 68 and form the detection surface of the pixels of the detector 80. In the detector 60 shown in FIG. 4a, the microcircuit 66 is located on one side of the interconnection level 68, while in the detector 80 shown in FIG. 4b, the microcircuit 66 is located on the opposite side of the interconnection level 68. In FIG. 4b, the microcircuit 66 is also located between two adjacent pixels. The arrangement of the detector 80 makes it possible, if desired, to arrange the microcircuit 66 partially facing the pads 74 and thus facing the pixels of the detector 80. In addition, if desired, pads 82 can be arranged on the side 32b of the substrate 62. The pads 82 are connected to the interconnection level 70 through vias 84. The pads 82 perform the same function as the pads 32 and allow another microcircuit to be connected to it, if the detector requires it.

[0043] More generally, detectors 60 and 80 may include a scintillator 46 and a light detecting component, such as a photodiode 48, instead of a photodetector 64. Detectors 60 and 80 may include, associated with each pixel, one or more microcircuits disposed within the detector substrate 62 and / or on one of its outer surfaces.

[0044] Figures 5a and 5b show, in a front view for Figure 5a and in a cross-section for Figure 5b, a variant of a detector 90 according to the invention, comprising a substrate 92 as shown in Figure 1, a microcircuit 26, a light-emitting diode 56, here produced separately from the microcircuit 26, and a photodetector made of two parts: a scintillator 46 and a matrix of light-detecting components, for example a matrix of photodiodes 94. The matrix of light-detecting components may be produced on a separate substrate 96 and then transferred to the interconnection substrate 92 or may form part of the interconnection substrate. As before, each photodiode 94 comprises two electrodes 96 and 98, each connected to one of the interconnection levels through a via. The photodiodes 94 may be made, for example, of amorphous silicon or of an organic semiconductor material.

[0045] In the embodiment shown, the microcircuit 26 is common to the four photodiodes 94. The microcircuit 26 is positioned partially facing the four photodiodes 94 such that the vias connecting the microcircuit 26 to the various photodiodes 94 extend primarily perpendicular to the plane of the interconnect substrate 92.

[0046] Other components, such as thermal or mechanical sensors, may also be transferred in addition to or in place of the light emitting diodes 56. These other components, such as the microcircuits 26, may be individually associated with each pixel or each group of pixels, for example, four pixels.

[0047] Pooling a common microcircuit 26 across multiple adjacent pixels may of course be applied to all embodiments of the present invention.

[0048] Figures 6a and 6b show, in a front view for Figure 6a and in a cross-sectional view for Figure 6b, a variant of a detector 100 according to the invention, comprising a substrate 102 as shown in Figure 1, a number of microcircuits 26, one of which is illustrated, a matrix of photodiodes 104 and a scintillator 46. Unlike the detector 90, in the detector 100 the photodiodes 104, or more generally the light detection components, are integrated in the substrate 102.

[0049] 6a and 6b, the microcircuit 26 is associated with only one photodiode 104. It is also possible to pool the microcircuits 26 by associating them with several adjacent photodiodes 104.

[0050] The matrix of photodetection components is produced discontinuously in the detector 90 shown in Figures 5a and 5b and in the detector 100 shown in Figures 6a and 6b. Several manufacturing methods can be used for the photodetection components. As an example, one may mention the photolithography method commonly used for the matrix of photodetection components made of amorphous silicon on a glass-based substrate. It is also possible to use techniques for printing conductive inks and organic semiconducting materials.

Claims

1. A matrix photosensitive detector organized into pixels (30, 74; 94; 104), a planar substrate (10; 22; 62; 92; 102) having a plurality of interconnect levels (12, 14) connected to each other by through vias (16; 72; 84); a photodetector (24; 44; 64; 94; 104) arranged on a first outer surface (22a) of said flat substrate (10; 22; 62; 92; 102) and grouping said pixels (30, 74; 94; 104) of said photosensitive detector, configured to effect the conversion of radiation sensed by said detector by each of said pixels (30, 74; 94; 104) into an electrical signal; a semiconductor microcircuit (26; 66) configured to drive and read out each of said pixels, said microcircuit (26; 66) being arranged facing each of said pixels (30, 94; 104) or between adjacent pixels (74) perpendicular to said substrate (10; 22; 62; 92; 102), each microcircuit (26; 66) being carried on a microsubstrate (27) independent from the planar substrate (10; 22; 62; 92) of the photosensitive detector, said microcircuits (26; 66) being individually connected to said planar substrate (10; 22; 62; 92) at one of its interconnection levels, Matrix photosensitive detector.

2. 2. The photosensitive detector of claim 1, wherein the flat substrate (10; 22; 92) has a second outer surface (22b) and connection pads (32) disposed on the second outer surface (22b) and connected to the interconnect level (12, 14), and the microcircuit (26) is disposed on the second outer surface (22b) and connected to the connection pads (32).

3. 3. The device of claim 2, wherein the flat substrate (10; 22; 92; 102) has connection pads (30; 74) arranged on the first outer surface (22a) and connected to the interconnect level (12, 14), each of the connection pads (30; 74) on the first outer surface (22a) forming an individual electrode of one of the pixels.

4. 4. The device of claim 3, wherein the photodetector (24; 44; 64) is in the form of a continuous layer disposed on the connection pads (30; 74) of the first outer surface (22a).

5. 4. The device of claim 3, wherein the photodetector is formed from individual photodetecting components (94; 104) each forming one of the pixels.

6. The device of claim 4 , wherein the light-detecting component (104) is embedded in the planar substrate (102).

7. The photosensitive detector of claim 1 , wherein the microcircuit (66) is disposed within the planar substrate (62).

8. A device according to any one of the preceding claims, wherein the microcircuit (26; 66) is common to several adjacent pixels.

9. The device according to any one of claims 1 to 8, wherein the microcircuit (26; 66) is connected to the pixels (30, 74; 94; 104) of the photosensitive detector only through vias (16) perpendicular to a plane in which the flat substrate (10; 22; 62; 92; 102) mainly extends.

10. A method for making a photosensitive detector according to any one of claims 1 to 9, comprising the steps of: - making a planar substrate (10; 22; 62; 92) having a number of interconnect levels (12, 14) connected to each other by through vias (16; 72; 84); - fabricating semiconductor microcircuits (26; 66) configured to drive and read out each of said pixels, each on a microsubstrate separate from said planar substrate (10; 22; 62; 92; 102) of said photosensitive detector; transferring each microcircuit (26; 66) to the planar substrate (10; 22; 62; 92; 102) by individually connecting said microcircuit (26; 66) to one of said interconnect levels (12, 14), method.

11. 11. The method of claim 10, further comprising the step of testing said microcircuit (26; 66) before transferring said microcircuit (26; 66) to said planar substrate (10; 22; 62; 92; 102) of said photosensitive detector.

Images