KR20110005939A - Method of manufacturing scintillator and x-ray detector - Google Patents

Abstract

PURPOSE: A manufacturing method of a scintillator an x-ray detector is provided to use shadow mask and form scintillator, which is patterned in uniformed shape through whole area, thereby improving detection ability and reduce the deterioration of resolution characteristic. CONSTITUTION: A method of manufacturing a scintillator is as follows. An X-ray prepares a transmitted support substrate(110). On single-side of a support substrate, a shadow mask(120), which grid shaped opening unit is formed, is arranged. The scintillator is formed by protecting a scintillator, which is for converting wavelength of an X-ray, on one side of a support substrate. The opening unit is formed on slit shape which is expanded to one direction. The opening unit is formed with a shape which holes of square shape is arranged in a baduk board shape or zig-zag shape.

Description

Manufacturing method of scintillator and X-ray detector {METHOD OF MANUFACTURING SCINTILLATOR AND X-RAY DETECTOR}

The present invention relates to a method of manufacturing a scintillator and an X-ray detector, and more particularly, to a method of manufacturing a scintillator and an X-ray detector used to detect an image of a subject taken by X-rays.

Diagnostic x-ray examination methods widely used in the prior art had to take a film using an X-ray detection film, and the predetermined film printing process to know the result. In recent years, however, with the development of semiconductor technology, digital x-ray detectors using thin film transistors and photoelectric conversion devices have been developed.

The digital x-ray detector includes a photoelectric conversion substrate for converting light into electricity and a scintillator for converting x-rays into light absorbed by the photoelectric conversion substrate. In the photoelectric conversion substrate, a plurality of thin film transistors and photoelectric conversion elements are arranged in a matrix. In this case, the photoelectric conversion device may be formed of, for example, a photo diode or a charge coupled device (CCD) including a p-type semiconductor layer, an intrinsic semiconductor layer, and an n-type semiconductor layer.

The X-ray detector converts X-rays radiated from the outside into visible light by using a scintillator, and converts the electrons generated by the photoelectric conversion element by the visible light to the outside by applying a bias voltage to convert the X-ray into an analog electric signal. The analog electric signal, which appears very different, is converted into a digital electric signal through an AD converter, and finally the digital image is displayed on the display device.

On the other hand, as a method of forming a scintillator on a photoelectric conversion substrate, a method of attaching a scintillator having a scintillator layer formed on a flat support substrate onto an photoelectric conversion substrate using an adhesive and a scintillator layer on the photoelectric conversion substrate The method of forming directly on a phase, etc. are mentioned, for example. In this case, the scintillator layer is formed by depositing phosphors such as halogen compounds such as cesium iodide (CsI), which is a high-brightness fluorescent material, and oxide compounds such as gadolinium sulfate (GOS), by deposition, electrobeam, or sputtering methods. Columnar single crystal structure.

However, it takes a long time to form a scintillator layer having a columnar single crystal structure on a supporting substrate or a photoelectric conversion substrate, and since the formed column shape is not uniform, optical until the visible light from the scintillator layer reaches the photoelectric conversion element. There is a problem that degradation of resolution characteristics occurs due to phosphorus diffusion and scattering.

Accordingly, the present invention has been made in view of such a problem, and the present invention provides a method of manufacturing a scintillator and an X-ray detector capable of simply and precisely forming a scintillator layer.

According to the method of manufacturing a scintillator according to an aspect of the present invention, after preparing a support substrate through which X-rays are transmitted, a shadow mask having a grid opening is formed on one surface of the support substrate. Thereafter, a scintillator material for converting the wavelength of the X-ray is formed on one surface of the support substrate to form a scintillator layer.

The opening is formed in a slit shape extending in one direction. Alternatively, the opening may be formed in a shape in which rectangular holes are arranged in a checkerboard shape or a zigzag shape.

Annealing may be further performed to crystallize the scintillator layer. In addition, a process of forming a protective film for protecting the scintillator layer may be further performed.

According to the method of manufacturing an X-ray detector according to an aspect of the present invention, a photoelectric conversion layer including a photoelectric conversion unit is formed on an insulating substrate to form a photoelectric conversion substrate. Subsequently, after a shadow mask having grid openings formed on the photoelectric conversion substrate, a scintillator material for converting the wavelength of the X-ray is formed on the photoelectric conversion substrate to form a scintillator layer. The opening is formed in a slit shape extending in one direction. Alternatively, the opening may be formed in a shape in which rectangular holes are arranged in a checkerboard shape or a zigzag shape. Annealing may be further performed to crystallize the scintillator layer. In addition, a process of forming a protective film for protecting the scintillator layer may be further performed.

According to the method of manufacturing the scintillator and the X-ray detector, by using a shadow mask to form a patterned scintillator layer in a uniform form over the entire area, resolution such as blurring due to optical diffusion and scattering It is possible to reduce the deterioration of characteristics and to improve the detection ability. In addition, productivity can be improved by increasing the deposition rate of the scintillator layer.

The above-described features and effects of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, and thus, those skilled in the art to which the present invention pertains may easily implement the technical idea of the present invention. Could be. The present invention is not limited to the following embodiments and may be implemented in other forms. The embodiments introduced herein are provided to make the disclosure more complete and to fully convey the spirit and features of the present invention to those skilled in the art. In the drawings, the thickness of each device or film (layer) and regions has been exaggerated for clarity of the invention, and each device may have a variety of additional devices not described herein. When (layer) is mentioned as being located on another film (layer) or substrate, an additional film (layer) may be formed directly on or between the other film (layer) or substrate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 7 are process diagrams illustrating a manufacturing process of a scintillator according to an embodiment of the present invention.

Referring to FIG. 1, first, a support substrate 110 through which X-rays are transmitted is prepared for the manufacture of the scintillator. The support substrate 110 is formed of a material through which X-rays can be transmitted. For example, the support substrate 110 may be formed of a metal such as aluminum (Al) or titanium (Ti). As such, when the support substrate 110 is formed of metal, the visible light generated in the scintillator layer to be formed later may be reflected, thereby improving light utilization efficiency. The support substrate 110 formed of aluminum (Al) is, for example, formed to a thickness of about 0.3 mm to 1.0 mm. When the thickness of the support substrate 110 formed of aluminum (Al) is less than about 0.3 mm, the scintillator layer is easily peeled off due to the bending of the support substrate 110, and when the thickness of the support substrate 110 exceeds about 1.0 mm, The transmittance of the X-ray may be lowered. On the other hand, the support substrate 110 may be formed of an organic material, such as glass, carbon, ceramics.

Thereafter, a shadow mask 120 is disposed on one surface of the support substrate 110. In the shadow mask 120, grid openings 122 corresponding to the scintillator layer to be formed are formed. The shadow mask 120 may be made of, for example, metal or stainless steel (SUS). The opening 122 formed in the shadow mask 120 serves as a passage through which the scintillator material passes through the opening 122 and is deposited on the support substrate 110 in the process of depositing the scintillator layer. A plurality of openings 122 are formed corresponding to the pattern of the scintillator layer to be formed on the support substrate 110. The openings 122 are formed in a slit shape extending in one direction, for example, and are formed to be spaced apart from each other by a predetermined interval. On the contrary, the openings 122 may be formed in a shape in which rectangular holes are arranged in a checkerboard shape or a zigzag shape. Meanwhile, a protective film made of silicon oxide, silicon nitride, or the like may be formed on the surface of the shadow mask 120 to planarize the surface of the shadow mask 120.

Referring to FIG. 2, in a state where the shadow mask 120 is disposed on the support substrate 110, a scintillator material is formed on one surface of the support substrate 110 to form the scintillator layer 130. The scintillator layer 130 may be formed, for example, by evaporation. The deposition method is a method in which a raw material of scintillator material is placed in a crucible in a vacuum chamber and heated to be evaporated to form the support substrate 110. The shadow mask 120 is formed on one surface of the support substrate 110 in the vacuum chamber. And the evaporated raw material of the scintillator material to form the patterned scintillator layer 130. That is, when the raw material of the scintillator material is evaporated in the vacuum chamber, the scintillator material is deposited only in the opening 122 of the shadow mask 120 to form the patterned scintillator layer 130.

The scintillator layer 130 formed through such a process is a fluorescence for converting X-rays incident from the support substrate 110 to light in a wavelength band that can be absorbed by a photoelectric conversion substrate (not shown), for example, visible light in a green wavelength band. Contains substances. For example, the scintillator layer 130 is formed of a halogen compound such as cesium iodide (CsI) doped with thallium (Tl) or sodium (Na), or an oxide type such as gadolinium sulfur oxide (GOS). It may include a compound. The scintillator layer 130 may be formed, for example, in a thickness of about 100 μm to 1000 μm, and particularly preferably in a thickness of about 450 μm to 550 μm.

The scintillator layer 130 is formed in an amorphous or polycrystalline crystalline form through a deposition process such as evaporation or sputtering. As such, by forming the scintillator layer 130 in the form of an amorphous or poly-nodular crystal using the shadow mask 120, the formation speed of the scintillator layer 130 can be greatly improved compared to conventional single crystals.

2 and 3, after the scintillator layer 130 is formed, only the scintillator layer 130 is present on the support substrate 110 when the shadow mask 120 is removed. As such, by forming the scintillator layer 130 patterned through the shadow mask 120, the scintillator layer 130 having a regular and precise shape can be formed in a short time. Each pattern of the scintillator layer 130 is formed to have a depth of about 100 μm to 600 μm and a width of about 5 μm to 10 μm, and the spacing is formed at a rate of about 50% to 90% of the width. do.

On the other hand, in order to improve the light conversion efficiency of the scintillator layer 130, it is necessary to change the scintillator layer 130 in an amorphous or polycrystalline state to a single crystal state. To this end, an annealing process for crystallization of the scintillator layer 130 may be further performed. The annealing process may optionally proceed before or after removal of the shadow mast 120.

As shown in FIG. 4, the scintillator layer 130 formed through the above process is formed in a straight shape extending in one direction to correspond to the shape of the opening 122 of the shadow mask 120. Unlike this, the scintillator layer 130 may be formed in a shape in which square protrusions are arranged in a checkerboard shape, as shown in FIG. 5. In addition, as illustrated in FIG. 6, the scintillator layer 130 may be formed in a shape in which protrusions having a rectangular pillar shape are arranged in a zigzag shape.

As such, when the scintillator layer 120 is formed through the shadow mask 120, a uniform pattern may be formed over the entire region of the scintillator layer 130, and thus blurring due to optical diffusion and scattering may occur. It is possible to reduce deterioration of resolution characteristics such as blurring and to improve detection capability. In addition, by forming the scintillator layer 130 using the shadow mask 120, it is possible to improve the formation speed and reduce the manufacturing cost compared to other methods such as photolithography.

Referring to FIG. 7, a passivation layer 140 may be further formed to protect the scintillator layer 130. The passivation layer 140 is formed on one surface of the support substrate 110 to cover the scintillator layer 130. Alternatively, the passivation layer 140 may be formed to cover the entirety of the support substrate 110 and the scintillator layer 130. The passivation layer 140 may be formed of an organic material or an inorganic material. For example, the protective layer 140 may be made of poly para-xylylene, polymonochloro paraxylene, polydichloro paraxylene, polytetrachloro paraxylene, polyfluoro paraxyl It may be formed of an organic material of xylene series, such as ylene, polydimethyl paraxylene, polydiethyl paraxylene. In addition, the protective layer 140 may be formed of polyurea, polyimide, or the like, or may be formed of an inorganic material such as SiO ₂ , SiN, LiF, MgF ₂ , Al ₂ O ₃ , TiO ₂ , MgO, or the like.

8, 9 and 10 are process diagrams illustrating a manufacturing process of an X-ray detector according to an exemplary embodiment of the present invention.

Referring to FIG. 8, first, a photoelectric conversion layer 220 is formed on an insulating substrate 210 to manufacture an X-ray detector. The insulating substrate 210 is formed of a transparent and insulating material such as glass or plastic. The photoelectric conversion layer 220 includes a thin film transistor and a photoelectric conversion part respectively formed in a plurality of pixel areas formed in a matrix form on the insulating substrate 210. The photoelectric conversion unit is a portion in which X-rays incident from the outside absorb light converted in the scintillator layer and converts the light into an electrical signal, for example, a photodiode or a CCD. The thin film transistor is a switching device for sequentially outputting an electrical signal generated by the photoelectric conversion unit to an external circuit.

Subsequently, a shadow mask 120 having a grid opening 122 is formed on the photoelectric conversion substrate 210. Since the shadow mask 120 has been described with reference to FIG. 1, detailed descriptions thereof will be omitted.

Subsequently, a scintillator material for converting the wavelength of the X-rays is deposited on the photoelectric conversion substrate 210 to form the patterned scintillator layer 130 as shown in FIG. 9. Since the method for forming the scintillator layer 130 using the shadow mask 120 has been described with reference to FIG. 2, detailed descriptions thereof will be omitted.

Meanwhile, after deposition of the scintillator layer 130, an annealing process for crystallization of the scintillator layer 130 may be selectively performed before or after removal of the shadow mast 120 of the shadow mask 120. .

Thereafter, referring to FIG. 10, a passivation layer 140 may be further formed to protect the scintillator layer 130. Since the protective layer 140 has been described with reference to FIG. 7, detailed descriptions thereof will be omitted.

As such, by directly forming the scintillator layer 130 on the photoelectric conversion substrate 210, a process of attaching a separate scintillator may be eliminated, thereby reducing manufacturing cost and reducing the thickness of the X-ray detector. .

11 is an enlarged plan view of a pixel area of a photoelectric conversion layer according to an exemplary embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along the line II-II ′ of FIG. 11.

11 and 12, the process of forming the photoelectric conversion layer 220 may be roughly divided into the process of forming the thin film transistor unit 700 and the process of forming the photoelectric conversion unit 800. First, in order to form the thin film transistor unit 700, a gate line including a gate line GL and a gate electrode 710 electrically connected to the gate line GL is formed on the insulating substrate 210. . The gate wiring may be formed by depositing a gate metal film on the insulating substrate 210 by sputtering or the like, and then patterning the gate metal film through a photolithography process using an exposure mask. The gate wiring is, for example, aluminum (Al), molybdenum (Mo), chromium (Cr), neodymium (Nd), tantalum (Ta), titanium (Ti), tungsten (W), copper (Cu), silver ( Ag) or a single metal or an alloy thereof. In addition, the gate wiring may be formed in a multilayer structure in which the single metal or the alloy is stacked in a plurality of layers.

Thereafter, a first insulating layer 720 is formed on the insulating substrate 210 on which the gate wiring is formed. The first insulating layer 720 is an insulating layer for insulating and protecting the gate wiring, and may be formed of, for example, silicon nitride (SiNx) or silicon oxide (SiOx).

Thereafter, the active layer 730 is formed on the first insulating layer 720 to overlap the gate electrode 710. For example, a semiconductor thin film for forming the semiconductor layer 732 and an ohmic contact thin film for forming the ohmic contact layer 734 are formed on the first insulating layer 720, and then patterned to form the semiconductor layer 732. And an active layer 730 including an ohmic contact layer 734.

Thereafter, the source electrode 740 connected to the data line DL and the data line DL and extending to the upper portion of the active layer 730 on the first insulating layer 720 and the source electrode on the active layer 730. A data line is formed to include a drain electrode 750 spaced apart from the 740 and electrically connected to the lower electrode 810. The data line may be formed by depositing a data metal film on the insulating substrate 210 on which the active layer 730 is formed by sputtering or the like, and then patterning the data metal film through a photolithography process using an exposure mask. . For example, the data line may include aluminum (Al), molybdenum (Mo), chromium (Cr), neodymium (Nd), tantalum (Ta), titanium (Ti), tungsten (W), copper (Cu), and silver ( Ag) or a single metal or an alloy thereof. In addition, the data line may be formed in a multilayer structure in which the single metal or alloy is stacked in a plurality of layers.

Meanwhile, by using a slit mask or a halftone mask to pattern the data line, the active layer 730 may be simultaneously patterned together with the data line using one mask.

Thereafter, the ohmic contact layer 734 of the channel region corresponding to the source electrode 740 and the drain electrode 750 is removed to expose the semiconductor layer 732 of the channel region.

Meanwhile, after the thin film transistor unit 700 is formed, the photoelectric converter 800 electrically connected to the drain electrode 750 of the thin film transistor unit 700 is formed.

In order to form the photoelectric converter 800, a lower electrode 810 electrically connected to the drain electrode 750 is formed. The lower electrode 810 of the photoelectric converter 800 may be formed from the same metal layer as the drain electrode 750 as shown in FIG. 12. That is, during patterning of the data metal layer for forming the data line, the lower electrode 810 connected to the drain electrode 750 may be simultaneously formed. Alternatively, the lower electrode 810 may be formed of a transparent conductive film such as ITO so as to be electrically connected to the drain electrode 750 before or after the drain electrode 750 is formed.

Thereafter, the n-type silicon layer 820, the intrinsic silicon layer 830, and the p-type silicon layer 840 are sequentially formed on the lower electrode 810. The intrinsic silicon layer 830 may be formed of amorphous silicon or microcrystalline silicon. The n-type silicon layer 820, the intrinsic silicon layer 830, and the p-type silicon layer 840 may be formed through a plasma chemical vapor deposition (PE-CVD) process.

Thereafter, the upper electrode 850 is formed on the p-type silicon layer 840. The upper electrode 850 may be formed by forming a transparent conductive film made of a transparent conductive material on the insulating substrate 210 on which the p-type silicon layer 840 is formed, and then patterning the transparent conductive film.

Thereafter, the second insulating layer 860 is formed on the insulating substrate 210 on which the photoelectric conversion part 800 is formed to cover the thin film transistor part 700 and the photoelectric conversion part 800. The second insulating layer 860 is an insulating layer for protecting and insulating the thin film transistor unit 700 and the photoelectric conversion unit 800, and may be formed of, for example, silicon nitride (SiNx) or silicon oxide (SiOx). have. A contact hole CNT exposing a portion of the upper electrode 850 is formed in the second insulating layer 860. Meanwhile, an organic layer (not shown) may be further formed on the second insulating layer 860. The organic layer is formed to a thickness thicker than that of the second insulating layer 860 in order to planarize the photoelectric conversion layer 220 and reduce the parasitic capacitor.

Thereafter, a bias line 870 is formed on the second insulating layer 860 to be electrically connected to the photoelectric converter 800. The bias line 870 is for applying a bias to the photoelectric converter 800 and is electrically connected to the upper electrode 850 of the photoelectric converter 800 through the contact hole CNT formed in the second insulating layer 860. Is connected.

The bias line 870 may be formed to overlap at least a portion of the data line DL in order to increase the aperture ratio of the photoelectric converter 800, and to prevent light from flowing into the thin film transistor unit 700. It may be formed to cover the portion 700.

Thereafter, the passivation layer 880 is formed on the surface of the photoelectric conversion layer 220 on which the bias line 870 is formed. The protective film 880 is a film for protecting the surface of the photoelectric conversion layer 220 and may be formed of an organic material such as polyimide or an inorganic material such as silicon nitride (SiNx) or silicon oxide (SiOx). have. Meanwhile, an organic layer may be formed to a thick thickness on the passivation layer 880 to planarize the photoelectric conversion layer 220.

In the detailed description of the present invention described above with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described later in the claims and the spirit of the present invention It will be appreciated that various modifications and variations can be made in the present invention without departing from the scope of the art.

1 to 7 are process diagrams illustrating a manufacturing process of a scintillator according to an embodiment of the present invention.

8 to 10 are process diagrams illustrating a manufacturing process of an X-ray detector according to an exemplary embodiment of the present invention.

11 is an enlarged plan view of a pixel area of a photoelectric conversion layer according to an exemplary embodiment of the present invention.

12 is a cross-sectional view taken along the line II-II 'of FIG. 11.

<Explanation of symbols for the main parts of the drawings>

110: support substrate 120: shadow mask

122: opening 130: scintillator layer

140: protective film 220: photoelectric conversion layer

Claims (10)

Preparing a support substrate through which X-rays are transmitted; Disposing a shadow mask having a grid-shaped opening formed on one surface of the support substrate; And And forming a scintillator layer by depositing a scintillator material for converting the wavelength of the X-ray on one surface of the support substrate. The method of claim 1, The opening is a method of manufacturing a scintillator, characterized in that formed in a slit shape extending in one direction. The method of claim 1, The opening is a method of manufacturing a scintillator, characterized in that the rectangular holes are formed in a shape arranged in the form of a checkerboard or zigzag. The method of claim 1, The method of manufacturing a scintillator further comprises the step of annealing for crystallization of the scintillator layer. The method of claim 1, A method of manufacturing a scintillator, characterized in that it further comprises the step of forming a protective film for protecting the scintillator layer. Forming a photoelectric conversion substrate by forming a photoelectric conversion layer including a photoelectric conversion unit on an insulating substrate; Disposing a shadow mask having a grid-shaped opening formed on the photoelectric conversion substrate; And And forming a scintillator layer by depositing a scintillator material for converting the wavelength of the x-ray on the photoelectric conversion substrate. The method of claim 6, The opening is a manufacturing method of the X-ray detector, characterized in that formed in a slit shape extending in one direction. The method of claim 6, The opening is a manufacturing method of the X-ray detector, characterized in that formed in the shape of the rectangular holes arranged in the form of a checkerboard or zigzag. The method of claim 6, And annealing the crystallization of the scintillator layer. The method of claim 6, Forming a protective film for protecting the scintillator layer, characterized in that it further comprises a x-ray detector manufacturing method.

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