X-ray detector and method for manufacturing the same

Abstract

To provide an X-ray detector and a manufacturing method of the X-ray detector.SOLUTION: An X-ray detector comprises a photodiode layer including a plurality of photodiodes, and a plurality of pixel driving ICs which are arranged on the photodiode layer and each coupled to two or more photodiodes in the photodiode layer. A manufacturing method of the X-ray detector includes the steps of: forming the photodiode layer including the plurality of photodiodes on an insulating substrate; forming the plurality of pixel driving ICs on a single crystal semiconductor wafer ; and mounting the plurality of pixel driving ICs on the photodiode layer and coupling each of the plurality of pixel driving ICs to two or more photodiodes in the photodiode layer.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an X-ray detector and a method for manufacturing an X-ray detector, and more particularly to an X-ray detector including a plurality of photodiodes and a plurality of pixel driving integrated chips (ICs), each of which controls the plurality of photodiodes simultaneously or sequentially, and a method for manufacturing the same. [Background technology]

[0002] Digital X-ray detectors are widely used in medical and industrial radiography. Digital X-ray detectors are commonly called X-ray detectors or image detectors. Digital detectors are classified into indirect conversion type and direct conversion type. Indirect conversion type X-ray detectors i) use a scintillator to convert X-rays (e.g., X-ray photons) into visible light (e.g., photons) and ii) convert the visible light into an electrical signal. Direct conversion type X-ray detectors use a photoconductive material to directly convert X-rays into an electrical signal.

[0003] The X-ray detector detects X-rays emitted from an X-ray source, transmitted through an object to be imaged, and reached the X-ray detector. The X-ray detector converts the detected X-rays into an electrical signal. The X-ray detector includes a pixel array panel including a plurality of pixels. Each pixel includes a light receiving element (e.g., a photoconductor or a photodiode) and a driving element for driving the light receiving element of each pixel.

[0004] X-ray detectors can be manufactured by a thin-film transistor (TFT) process based on an insulating substrate or a complementary metal-oxide-semiconductor (CMOS) process based on a single crystal semiconductor wafer. The TFT process is advantageous in manufacturing a large-area X-ray detector at low manufacturing costs. The CMOS process is advantageous in manufacturing a high-quality X-ray detector. In contrast, the TFT process may have limitations in manufacturing a high-quality X-ray detector due to the use of amorphous semiconductors or polycrystalline semiconductors. The CMOS process may have limitations in manufacturing a large-area X-ray detector due to the size of the single crystal semiconductor wafer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-112434 A [Patent Document 2] Special Publication No. 2018-528408 Summary of the Invention [Problem to be solved by the invention]

[0006] The objective of the present invention is to provide a specific method for mass-producing high-quality, large-area X-ray detectors. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an X-ray detector comprising: a photodiode layer including a plurality of photodiodes; and a plurality of pixel driving ICs disposed on the photodiode layer and respectively connected to two or more photodiodes in the photodiode layer.

[0008] The present invention also provides a method for manufacturing an X-ray detector, comprising the steps of forming a photodiode layer including a plurality of photodiodes on an insulating substrate, forming a plurality of pixel driving ICs on a single crystal semiconductor wafer, and mounting the plurality of pixel driving ICs on the photodiode layer and connecting each of the plurality of pixel driving ICs to two or more photodiodes in the photodiode layer. Effect of the Invention

[0009] According to the present invention, an X-ray detector with high image quality and a large area can be provided. In particular, the X-ray detector can include i) a photodiode layer including a plurality of photodiodes that are manufactured separately from a pixel driving IC and arranged in a matrix-like pixel array, and ii) a pixel driving IC that is manufactured separately from the photodiode layer, mounted on the photodiode layer, and connected to the plurality of photodiodes to simultaneously or sequentially control the plurality of photodiodes.

[0010] The photodiode layer can be manufactured using a TFT process, which is advantageous for obtaining a large-area X-ray detector at a low unit price, and the pixel driving IC can be manufactured using a CMOS process, which makes it possible to obtain a high-quality X-ray detector.

[0011] In particular, the pixel driving ICs can be formed on a single crystal semiconductor wafer and then transferred to a stamp and mounted onto the photodiode layer.

[0012] Therefore, the X-ray detector according to the present invention can achieve high quality and a large area. In addition, since one pixel driving IC controls multiple photodiodes, the X-ray detector according to the present invention can have a relatively simple structure with a reduced number of metal wirings, etc. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing X-ray photography using an X-ray detector according to an embodiment of the present invention. [Diagram 2]1 is a diagram showing an internal structure of an X-ray detector according to an embodiment of the present invention; [Diagram 3] FIG. 1 is a circuit diagram showing a pixel driving IC according to an embodiment of the present invention. [Figure 4] 2 is a cross-sectional view of a pixel area of ​​a front-illuminated X-ray detector according to an embodiment of the present invention; [Diagram 5] 2 is a cross-sectional view of a pixel area of ​​a back-illuminated X-ray detector according to an embodiment of the present invention. [Figure 6] 5 is a flowchart showing a method for manufacturing an X-ray detector according to an embodiment of the present invention. [Figure 7] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 8] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 9] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 10] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 11] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 12] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 13] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 14] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 15] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 16] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 17] 5A to 5C are cross-sectional views for explaining a manufacturing method of a front illumination type X-ray detector according to an embodiment of the present invention. [Figure 18] 5A to 5C are cross-sectional views for explaining a manufacturing method of a back-illuminated X-ray detector according to an embodiment of the present invention. [Figure 19] 5A to 5C are cross-sectional views for explaining a manufacturing method of a back-illuminated X-ray detector according to an embodiment of the present invention. [Figure 20] 5A to 5C are cross-sectional views for explaining a manufacturing method of a back-illuminated X-ray detector according to an embodiment of the present invention. [Figure 21] 1 is a diagram for explaining a method of mounting a plurality of pixel driving ICs on a photodiode layer of an X-ray detector according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an X-ray detector and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings. For ease of explanation and understanding, the X-ray detector may be an X-ray detector that receives X-rays transmitted through an object to be imaged and converts the received X-rays to generate an electrical signal. However, the embodiment of the present invention is not limited thereto. The X-ray detector may also be called an image detector, an image sensor, a digital detector, etc.

[0015] FIG. 1 is a diagram showing X-ray photography using an X-ray detector according to one embodiment of the present invention. 1, an X-ray detector 10 and an X-ray source 20 can be disposed to face each other across an object to be imaged 30. The X-ray source 20 can generate X-rays and irradiate the generated X-rays toward the object to be imaged 30.

[0016] The X-ray detector 10 i) receives X-rays emitted from the X-ray source 20 and transmitted through the imaging target 30, and ii) directly or indirectly converts the received X-rays into an electrical signal. The X-ray detector 10 may have a flat rectangular shape, but the shape of the X-ray detector 10 is not limited thereto.

[0017] According to one embodiment, the X-ray detector 10 may be an indirect conversion type that receives X-rays transmitted through the imaging target 30 and converts the received X-rays into visible light. In this case, the X-ray detector 10 may include a scintillator layer that converts X-rays into visible light. The scintillator layer may be made of cesium iodide (CsI), but the present invention is not limited thereto. For example, the X-ray detector 10 may be an X-ray detector of a direct conversion type that directly converts X-rays into an electrical signal. In this case, the scintillator layer may be omitted from the X-ray detector.

[0018] According to one embodiment, the X-ray detector 10 may include a photodiode layer and a plurality of pixel driving ICs that are realized in separate processes, and the plurality of pixel driving ICs may be mounted on the photodiode layer using a micro-transfer printing technique. Such a structure of the X-ray detector 10 allows for high quality and a large area.

[0019] Each pixel driving IC in the X-ray detector 10 can form a predetermined three-dimensional structure together with a photodiode layer, an inter-layer dielectric (ILD), and a contact electrode. Such a structure of the X-ray detector 10 can improve the fill factor and X-ray absorption rate, and minimize the X-ray exposure of the imaging subject 30. The fill factor means the ratio of the area of ​​the photodiode to the area of ​​a unit pixel.

[0020] According to an embodiment, the X-ray detector 10 may be a back side illumination type (BSI). In the case of a back side illumination type X-ray detector, a driving layer including a pixel driving IC is disposed under a photodiode layer, and a scintillator layer is formed on a lower electrode of the photodiode layer. Therefore, the light converted in the scintillator layer is not blocked by the pixel driving IC and the contact electrode and reaches the photodiode layer. Such a back side illumination type X-ray detector 10 further improves the fill factor.

[0021] According to one embodiment, the X-ray detector 10 may include a photodiode layer in which a plurality of photodiodes including amorphous silicon (a-Si) or polycrystalline silicon are arranged in a continuous layer structure or in an island array structure. In the case where the photodiodes are in a continuous layer structure, the manufacturing cost can be minimized, and in the case where the photodiodes are in an island array structure, the crosstalk between adjacent photodiodes can be minimized.

[0022] According to one embodiment, the x-ray detector 10 may be made relatively light and durable by utilizing laser lift-off techniques to remove an insulating substrate, such as a glass substrate.

[0023] The structure of the X-ray detector 10 according to one embodiment of the present invention will be described in more detail with reference to Fig. 2. Fig. 2 shows the internal structure of the X-ray detector according to one embodiment of the present invention.

[0024] As shown in Fig. 2, the X-ray detector 10 may include a pixel region 11, a gate driving circuit 12, a data driving circuit 13, and a control circuit 14. The pixel region 11 may be a main region that receives X-rays, converts the received X-rays into visible light, and converts the visible light into an electrical signal. That is, the pixel region 11 may be of an indirect conversion type. However, the present invention is not limited thereto. For example, the pixel region 11 may be of a direct conversion type. In the case of the direct conversion type, the scintillator layer is eliminated from the pixel region 11, and the pixel region 11 directly converts X-rays into an electrical signal using a photoconductive layer.

[0025] The pixel region 11 may include a plurality of pixels P arranged in a matrix. Each pixel P may include a photodiode that converts incident light into an electrical signal. Each pixel P may be connected to a gate driving circuit 12 via a gate line GL extending in a row direction and to a data driving circuit 13 via a data line DL extending in a column direction.

[0026] A typical X-ray detector includes a pixel driving element that is built into each pixel to read out the charge accumulated in the photodiode in the pixel and controls each photodiode. However, instead of a pixel driving element built into each pixel, the pixel of the X-ray detector according to the present invention can include a plurality of pixel driving ICs 1200 that are printed on the photodiode layer by micro-transfer printing technology separately from the photodiode layer.

[0027] In particular, the multiple pixel driving ICs 1200 of the X-ray detector according to the present invention can be manufactured on a single crystal semiconductor wafer by a CMOS process, and the manufactured multiple pixel driving ICs 1200 can be mounted on a photodiode layer.

[0028] Each pixel driving IC 1200 is connected to four photodiodes and can control four pixels simultaneously or sequentially. However, the present invention is not limited thereto. For example, one pixel driving IC 1200 can be connected to two photodiodes, three photodiodes, or five photodiodes as required. That is, one pixel driving IC 1200 can be connected to two or more photodiodes. The number of photodiodes connected to one pixel driving IC 1200 can vary depending on various factors such as the efficiency of the circuit design and the performance of the X-ray detector.

[0029] The pixel driving IC 1200 can simultaneously or sequentially control at least two photodiodes connected to each other in response to a gate signal from the gate driving circuit 12, and read out the charges accumulated in each of the at least two photodiodes by the data driving circuit 13. Such a pixel driving IC 1200 will be described in further detail with reference to FIG.

[0030] 2 again, the X-ray detector 10 may include a gate driving circuit 12, a data driving circuit 13, and a control circuit 14. The control circuit 14 generates a control signal and transmits the generated control signal to the gate driving circuit 12 and the data driving circuit 13 to control the operations of the gate driving circuit 12 and the data driving circuit 13. The control circuit 14 may transmit data read from the data driving circuit 13 to an image processing circuit (not shown) outside the X-ray detector 10 on a frame-by-frame basis.

[0031] The gate drive circuit 12 can control the output timing of the gate signal based on a gate control signal transmitted from the control circuit 14. The data drive circuit 13 can control the readout timing of the charge accumulated in the pixel P based on a data control signal transmitted from the control circuit 14.

[0032] As described above, the X-ray detector 10 according to the present invention includes a plurality of pixel driving ICs 1200, each of which is connected to at least two photodiodes and controls the at least two connected photodiodes simultaneously or sequentially. Such a pixel driving IC 1200 will be described in detail with reference to FIG. 3.

[0033] 3 is a circuit diagram showing a pixel driving IC according to an embodiment of the present invention. As shown in FIG. 3, the pixel driving IC 1200 is connected to four photodiodes PD1, PD2, PD3, and PD4, which are respectively built into four pixels, and can control the first to fourth photodiodes PD1, PD2, PD3, and PD4 simultaneously or sequentially. In particular, the pixel driving IC 1200 can turn on the first to fourth photodiodes PD1, PD2, PD3, and PD4 simultaneously or sequentially, and output the charges respectively accumulated in the first to fourth photodiodes PD1, PD2, PD3, and PD4 to the data driving circuit simultaneously or sequentially.

[0034] To control the four photodiodes simultaneously or sequentially, the pixel driving IC 1200 may include a timing generator 1210, a pixel driving transistor 1220, and four switches, first to fourth, 1231 to 1234. For example, the pixel driving IC 1200 is electrically connected to the first photodiode PD1 via the first switch 1231, electrically connected to the second photodiode PD2 via the second switch 1232, electrically connected to the third photodiode PD3 via the third switch 1233, and electrically connected to the fourth photodiode PD4 via the fourth switch 1234.

[0035] The timing generator 1210 can receive a clock signal CLK from the gate driving circuit 12 and generate timing signals for sequentially switching the first to fourth switches 1231 to 1234. According to at least one embodiment, the timing generator 1210 can be implemented with a digital counter or a shift register. In particular, in order to minimize the size of the pixel driving IC, the timing generator can use a 2-bit counter.

[0036] The pixel driving transistor 1220 is turned on by a timing signal from the timing generator 1210, and can output charges accumulated in at least one of the first to fourth photodiodes PD1 to PD4 to the data driving circuit 13. Such a pixel driving transistor 1220 can be realized as a three-transistor (3T) structure or a four-transistor (4T) structure.

[0037] As described above, in the X-ray detector according to the present invention, at least two, for example, four photodiodes PD1, PD2, PD3, and PD4 are controlled by one pixel driving IC 1200. Such a structure of the X-ray detector 10 minimizes the number of metal wirings connected to the pixels and the driver circuit, thereby improving the charging rate, simplifying the manufacturing process, and reducing the manufacturing cost.

[0038] FIG. 4 is a cross-sectional view of a pixel area of ​​an X-ray detector according to one embodiment of the present invention. 4 shows a pixel area of ​​a front side illumination type X-ray detector according to an embodiment of the present invention. As shown in FIG. 4, the pixel area of ​​the X-ray detector can include three main layers: a photodiode layer 100, a driving layer 200, and a scintillator layer 300.

[0039] According to one embodiment, the photodiode layer 100 may include a common lower electrode 720 formed on an insulating substrate 710, a plurality of photodiodes 730 arranged in a matrix on the lower electrode 720, and an upper electrode 740. As an example, the insulating substrate 710 may be a glass substrate.

[0040] Each of the photodiodes 730 can convert visible light into an electrical signal. Such photodiodes 730 can have a PIN diode structure including a P+ type region (e.g., a high concentration P type), an I type region, and an N type region.

[0041] The photodiode layer 100 can be manufactured using a TFT process. Thus, the photodiode layer 100 can be manufactured in a large area at a relatively low cost. The photodiode layer 100 can have a continuous layer structure in which a plurality of photodiodes 730 are continuously arranged. In this case, the manufacturing cost can be further reduced. Alternatively, the photodiode layer 100 can have an island array structure in which a plurality of photodiodes 730 are arranged in an island shape. In this case, crosstalk between adjacent photodiodes 730 can be minimized.

[0042] The driving layer 200 may include a plurality of pixel driving ICs 1200 each controlling at least two photodiodes, and contact electrodes 1400 connecting the plurality of pixel driving ICs 1200 to the corresponding at least two photodiodes 730. In one embodiment of the present invention, one pixel driving IC 1200 controls four photodiodes 730 simultaneously or sequentially. However, the present invention is not limited thereto. The number of photodiodes 730 controlled by one pixel driving IC 1200 may vary depending on various factors related to the design and function of the X-ray detector.

[0043] In particular, the pixel driving ICs 1200 are manufactured separately from the photodiode layer 100, mounted on the photodiode layer 100, and connected to at least two photodiodes via contact electrodes, etc. The pixel driving ICs 1200 are manufactured in a CMOS process and can be mounted on the photodiode layer 100 by micro-transfer printing technology. Therefore, the pixel driving ICs 1200 can exhibit the characteristics of a high-quality semiconductor device.

[0044] The scintillator layer 300 can be formed on the driving layer 200. The scintillator layer 300 can convert X-rays into visible light. The scintillator layer 300 can have flexible properties. The scintillator layer 300 can be formed of CsI or Gadox (Gd2O2:Tb).

[0045] FIG. 5 is a cross-sectional view of a pixel area of ​​an X-ray detector according to one embodiment of the present invention. 5 shows a pixel area of ​​a back-illuminated X-ray detector according to an embodiment of the present invention. As shown in FIG. 5, the pixel area of ​​the X-ray detector may include an actuation layer 200-1, a photodiode layer 100-1, and a scintillator layer 300-1. Each of the actuation layer 200-1, the photodiode layer 100-1, and the scintillator layer 300-1 of the back-illuminated X-ray detector may have a structure similar to that of the corresponding layer of the front-illuminated X-ray detector.

[0046] Meanwhile, as shown in Fig. 5, the photodiode layer 100-1 of the backside illumination type X-ray detector may be located on the driving layer 200-1. That is, the driving layer 200-1 and the photodiode layer 100-1 of Fig. 5 may have a vertically symmetrical structure with respect to Fig. 4. For example, the driving layer 200-1 is formed on the photodiode layer 100-1, and the resultant structure on which the driving layer 200-1 and the photodiode layer 100-1 are formed is turned over. Then, the outer surface of the driving layer 200-1 is bonded to the carrier layer 1920 with an adhesive material 1910.

[0047] 5, the metal contacts and pixel driver ICs of the back-illuminated X-ray detector do not obstruct the photodiode 730. Therefore, the back-illuminated X-ray detector can transmit light to the photodiode 730 without loss, i.e., the fill factor is maximized.

[0048] Also, before the resultant structure of the driving layer 200-1 and the photodiode layer 100-1 is turned over, the insulating substrate 710 can be removed using a laser lift off technique, and the barrier layer 1820 and the scintillator layer 1720 made of a flexible material are formed on the photodiode layer 100-1, thereby improving the durability and flexibility of the X-ray detector.

[0049] As with the front-illumination type X-ray detector, the photodiode layer 100-1 can be manufactured by a TFT process. Therefore, the photodiode layer 100-1 can be manufactured into a large-area X-ray detector at a relatively low cost. Also, the photodiode layer 100-1 can have a continuous layer structure in which a plurality of photodiodes are continuously arranged. In this case, the manufacturing cost can be further reduced. Alternatively, the photodiode layer 100-1 can have an island array structure in which a plurality of photodiodes are arranged in an island shape. In this case, crosstalk between adjacent photodiodes can be minimized.

[0050] Similar to the front-illuminated X-ray detector, the driving layer 200-1 may include a plurality of pixel driving ICs each controlling at least two photodiodes, and contact electrodes connecting the plurality of pixel driving ICs to the corresponding photodiodes 730. In this embodiment, one pixel driving IC 1200 controls four photodiodes sequentially or simultaneously. However, the present invention is not limited thereto. The number of photodiodes controlled by one pixel driving IC 1200 may vary depending on various factors related to the X-ray detector.

[0051] In particular, the pixel driving ICs 1200 are manufactured separately from the photodiode layer 100, mounted on the photodiode layer 100, and connected to at least two photodiodes via contact electrodes or the like. The pixel driving ICs 1200 can be manufactured in a CMOS process and mounted on the photodiode layer 100 using a microtransfer printing technique. Therefore, the pixel driving ICs 1200 can exhibit high-quality semiconductor device characteristics.

[0052] The photodiode layer 100-1 may include a common lower electrode 720, a plurality of photodiodes 730 arranged on the lower electrode 720 in a matrix form, and an upper electrode 740, similar to a front-illuminated X-ray detector. The plurality of photodiodes 730 may convert visible light into an electrical signal. Such a photodiode 730 may have a PIN diode structure including a P+ type region (e.g., high-concentration P type), an I type region, and an N type region.

[0053] Unlike the front-illumination type X-ray detector, a scintillator layer 300-1 can be formed on the photodiode layer 100-1. Such a scintillator layer 300-1 can convert X-rays into visible light. The scintillator layer 300-1 can include a scintillator layer 1720 and a barrier layer 1820, which can be made of a material having flexible properties. The scintillator layer 1720 can be made of CsI or Gadox (Gd2O2:Tb).

[0054] Hereinafter, a method for manufacturing an X-ray detector according to an embodiment of the present invention will be described with reference to FIGS. Fig. 6 is a flowchart showing a method for manufacturing an X-ray detector according to an embodiment of the present invention. Figs. 7 to 17 are cross-sectional views for explaining a method for manufacturing a front-illumination type X-ray detector according to an embodiment of the present invention. Figs. 18 to 20 are cross-sectional views for explaining a method for manufacturing a back-illumination type X-ray detector according to an embodiment of the present invention.

[0055] 6, a photodiode layer 100 may be formed in step S6010. In particular, a plurality of photodiodes 730 may be formed on an insulating substrate 710 in step S6010. FIG 7 illustrates a step of forming a photodiode layer according to an embodiment of the present invention.

[0056] As shown in FIG. 7, a common bottom electrode 720 may be formed on an insulating substrate 710. The insulating substrate 710 may be made of a flexible material. The bottom electrode 720 may be made of indium tin oxide (ITO) or indium zinc oxide (IZO), but the present invention is not limited thereto. In particular, the bottom electrode 720 may be a transparent layer in the case of a back-illuminated X-ray detector. However, the bottom electrode 720 may be an opaque layer in the case of a front-illuminated X-ray detector. A plurality of photodiodes 730 are formed on the bottom electrode 720. The photodiodes 730 may include amorphous silicon (a-Si) or polycrystalline silicon. The photodiodes 730 may be formed by forming an i-Si layer on the bottom electrode 720, forming a p-Si layer on the i-Si layer, and forming an n-Si layer on the p-Si layer.

[0057] The top electrode 740 may be formed on the photodiode 730. The top electrode 740 may be made of indium tin oxide (ITO) or indium zinc oxide (IZO), but the present invention is not limited thereto. In particular, the top electrode 740 may be a transparent layer in the case of a front-illuminated X-ray detector. In contrast, the top electrode 740 may be an opaque layer in the case of a back-illuminated X-ray detector. As described above, the photodiode layer 100 may be manufactured using a TFT process. The photodiode layer 100 may be formed in a continuous layer structure to minimize manufacturing costs. Also, the photodiode layer 100 may be formed in an island-like matrix array structure as shown in the figure to minimize crosstalk between adjacent photodiodes.

[0058] 6, in steps S6020 to S6050, the driving layer 200 may be formed on the photodiode layer 100. FIGS. 8 to 14 are views illustrating a process of forming the driving layer 200 on the photodiode layer 100 according to an embodiment of the present invention and will be referred to together with FIG. 6.

[0059] 8, a first insulating layer 810 may be formed to cover all the photodiodes 730 and the gaps therebetween, and a plurality of first contact holes 820 may be formed in the first insulating layer 810. One first contact hole 820 may be formed in the first insulating layer 810 for each pixel, and the upper electrodes 740 of the corresponding photodiodes may be exposed.

[0060] In step S6030, as shown in FIG. 9, a first contact electrode 910 may be formed to fill the first contact hole 820 and extend a predetermined length along the top surface of the first insulating layer 810.

[0061] 10, a second insulating layer (ILD2) 1010 may be formed on the first contact electrode 910 and the first insulating layer 810, and a plurality of second contact holes 1020 may be formed in the second insulating layer 1010. One second contact hole 1020 may be formed in the second insulating layer 1010 for each pixel, exposing the corresponding first contact electrode 910 to the outside.

[0062] 11, an adhesive layer 1110 may be formed on the second insulating layer 1010 and the second contact hole 1020. The adhesive layer 1101 may be made of a predetermined resin material and may have a thickness of about 1.2 μm. The adhesive layer 1101 is for mounting the pixel driving IC 1200 thereon.

[0063] In step S6061, pixel driving ICs 1200 can be mounted on the adhesive layer 1100, as shown in FIG. 12. The pixel driving ICs can be mounted by a micro-transfer printing method. Each pixel driving IC 1200 can be located between two adjacent photodiodes in cross section and four adjacent photodiodes in three dimensions. In a preferred embodiment of the present invention, the pixel driving IC 1200 can be located in a position that can simultaneously or sequentially control at least four photodiodes.

[0064] Hereinafter, the micro-transfer printing process will be described with reference to Fig. 21. Fig. 21 illustrates a micro-transfer printing process for mounting a plurality of pixel driving ICs on a photodiode layer, and should be referred to in conjunction with Fig. 6.

[0065] In step S6061, as shown in FIG. 21, pixel driving ICs 1200 can be fabricated by a CMOS process on a single crystal semiconductor wafer 2510 for high image quality. Thus, the pixel driving ICs can include a single crystal semiconductor. In the next step S6062, the pixel driving ICs 1200 on the single crystal semiconductor wafer 2510 can be transferred to a stamp 2520. As an example, the stamp can be an elastomeric material having elasticity and flexibility. In step S6063, the pixel driving ICs 1200 can be printed on the adhesive layer 1101 on the photodiode layer 100 by pressing the stamp and the photodiode layer 100. In step S6064, after printing the pixel driving ICs, the stamp 2520 can be removed.

[0066] Reference is again made to FIG. 6, together with the drawings separately noted. 12, as an example, the height of each pixel driving IC may be less than about 10 μm, and the thickness from the bottom electrode 720 to the adhesion layer 1110 may be less than about 5 μm.

[0067] In step S6070, as shown in FIG. 13, a third contact hole 1300 connected to the second contact hole 1020 can be formed adjacent to each pixel driving IC 1200 so that the first contact electrode 910 is exposed to the outside.

[0068] In step S6080, a second contact electrode 1400 can be formed to connect the pixel driving IC 1200 and the first contact electrode while filling the third contact hole 1300, as shown in FIG. 14. Thus, the pixel driving IC 1200 can be connected to the corresponding photodiode 730.

[0069] According to another embodiment of the present invention, as shown in Figure 15, the pixel driving IC 1200 can be directly formed on the first insulating layer 810 and connected to the corresponding photodiode 730 without the second insulating layer 2020 and the adhesive layer 1110. In this case, the manufacturing method can be further simplified.

[0070] According to another embodiment of the present invention, as shown in Figure 16, a pixel driving IC 1200 can be directly formed on the second insulating layer 1010 and connected to a corresponding photodiode 720 without an adhesive layer 1110. In this case, the manufacturing method can be relatively simplified.

[0071] 6 and 17, a protective layer 1710 is formed (S6090) on the adhesive layer 1110 and the pixel driving ICs 1200. Then, in step S6100, a scintillator layer 1720 can be formed on the protective layer 1710.

[0072] A pixel region of the front-illuminated X-ray detector 10 can be completed by forming a scintillator layer 1720 on the pixel driving IC 1200 and the protective layer 1710. The X-ray detector 10 can also be manufactured as a back-illuminated X-ray detector according to another embodiment. Hereinafter, a method for manufacturing a pixel region of a back-illuminated X-ray detector will be described with reference to FIGS. 18 to 20 together with FIG. 6.

[0073] 18 to 20 are cross-sectional views showing a manufacturing process of a back-illuminated X-ray detector according to one embodiment of the present invention. As shown in Fig. 18, a sacrificial layer 1810 is formed on an insulating substrate 710, and a barrier layer 1820 is formed on the sacrificial layer 1810 (S6010). The sacrificial layer 1810 is formed for laser lift-off (LLO). The barrier layer 1820 is made of a resin material such as polyimide, for example. After forming the barrier layer 1820, the photodiode layer 100 and the driving layer 200 can be formed on the barrier layer 1820 as shown in Figs. 14 to 17.

[0074] After forming the photodiode layer 100 and the driving layer 200 in step S6080, a laser lift-off process may be performed in step S6110 to remove the insulating substrate 710 and the sacrificial layer 1810, as shown in FIG.

[0075] As shown in FIG. 19, after the laser lift-off process (S6110), a flipping process (step S6120) is performed to flip the resulting structure consisting of the photodiode layer 100 and the driving layer 200, and in step S6130, the driving layer 200 is bonded to a carrier layer 1920 made of, for example, carbon, using an adhesive material 1910.

[0076] In step S6140, as shown in Figure 20, a scintillator layer 1720 is formed on the barrier layer 1820. By forming the scintillator layer 1720 on the barrier layer 1820, a pixel area of ​​a back-illuminated X-ray detector can be completed.

[0077] Although the embodiments of the present invention have been described, the above-mentioned embodiments are merely illustrative and should not be construed as limiting the technical idea of ​​the present invention. Many modifications are possible within the scope of the technical idea disclosed in this specification, and such modifications should be construed as being included in the present invention if they fall within the scope of the present invention. [Explanation of symbols]

[0078] 10 X-ray detector 300 Scintillator Layer 710 Insulating Substrate 720, PD1~PD4 photodiodes 1110 Adhesive layer 1200 Pixel Driving IC 1210 Timing Generator 1220 Pixel driving transistor 1231~1234 Switch 2510 Single crystal semiconductor wafer 2520 Stamp

Claims

1. a photodiode layer including a plurality of photodiodes; a gate drive circuit that outputs a gate signal; a data drive circuit for reading out the charges stored in the plurality of photodiodes; a plurality of pixel driving ICs disposed on the photodiode layer and respectively connected to two or more photodiodes in the photodiode layer; The plurality of pixel driving ICs include a timing generator for generating a timing signal in response to the gate signal; a plurality of switches respectively connected to the two or more photodiodes, the switches outputting the charges accumulated in the respective photodiodes to the data drive circuit; a pixel drive transistor that turns on the plurality of switches simultaneously or sequentially based on the timing signal.

2. The x-ray detector of claim 1 , wherein the plurality of pixel driving ICs are fabricated separately from the photodiode layer and mounted on the photodiode layer.

3. The x-ray detector of claim 1 , wherein the plurality of pixel driving ICs are connected to four photodiodes.

4. the photodiode includes an amorphous or polycrystalline semiconductor; The x-ray detector of claim 1 , wherein the plurality of pixel driving ICs comprise single crystal semiconductor.

5. 2. The x-ray detector of claim 1, further comprising a scintillator layer formed on said plurality of pixel driving ICs opposite said photodiode layer, said scintillator layer converting x-rays into visible light.

6. 2. The x-ray detector of claim 1, further comprising a scintillator layer formed on the photodiode layer opposite the plurality of pixel driving ICs, the scintillator layer converting x-rays into visible light.

7. The X-ray detector according to claim 1 , wherein each of the plurality of pixel driving ICs is connected to the two or more photodiodes by at least one contact electrode penetrating the photodiode layer.

8. forming a photodiode layer including a plurality of photodiodes on an insulating substrate; forming a plurality of pixel driving ICs on a single crystal semiconductor wafer; mounting the plurality of pixel driving ICs on the photodiode layer, and connecting each of the plurality of pixel driving ICs to two or more photodiodes in the photodiode layer; The plurality of pixel driving ICs include a timing generator for generating a timing signal; a plurality of switches respectively connected to the two or more photodiodes and configured to read out charges accumulated in the respective photodiodes; a pixel driving transistor that turns on the plurality of switches simultaneously or sequentially based on the timing signal; The step of mounting the plurality of pixel driving ICs on the photodiode layer includes: transferring the plurality of pixel driving ICs to a stamp; printing the plurality of pixel driving ICs onto the photodiode layer with the stamp.

9. The method of claim 8 , further comprising forming an adhesive layer on the photodiode layer, whereby the plurality of pixel driving ICs are adhered to the adhesive layer.

10. The method of claim 8 further comprising forming a scintillator layer on the plurality of pixel driving ICs opposite the photodiode layer.

11. The method of claim 8 further comprising forming a scintillator layer on the photodiode layer opposite the plurality of pixel driving ICs.

12. The method for manufacturing an X-ray detector according to claim 10 or 11, further comprising the step of removing the insulating substrate from the photodiode layer before forming the scintillator layer.

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