KR101923002B1 - Method for fabricating Array substrate of X Ray Detector - Google Patents

Abstract

The present invention discloses a method of manufacturing an array substrate of an x-ray detector. In the method of manufacturing an array substrate of an X-ray detector according to the present invention, a metal film formed on a photoconductive film is over-etched inward toward the lower edge of a photoresist pattern by a wet etching process using a photoresist pattern as a mask, Forming an electrode, and continuing a dry etching process to form a photoconductive layer having a smaller area than the negative electrode and a wider area than the positive electrode. Accordingly, the present invention has the effect of simplifying the process by forming the electrode and the photoconductive layer by a single mask process when forming the photodiode.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of fabricating an array substrate of an X-ray detector,

The present invention relates to a method of manufacturing an array substrate of an x-ray detector.

In general, a plate-like substrate for X-ray detection refers to a panel that converts image information of radiation into electrical signals and detects the radiation by detecting radiation transmitted through a human body to acquire image information.

Such an X-ray imaging apparatus should have a detecting element for detecting an X-ray passing through a subject and converting it into an electrical signal.

In the conventional technique, a TFT (Thin Film Transistor) is a flat panel composed of a set of cells having a pixel as a basic unit, and a detecting device using such a TFT substrate is arranged in a row in a panel arranged in an array form A gate electrode of each pixel is controlled to detect an electric signal through a data line of each pixel arranged in rows and an electric image signal corresponding to each pixel is applied to a display device such as a monitor to form a digital image.

Conventional digital X-ray detectors include a photoconductor that generates charges proportional to an irradiation dose of X-rays, a collecting electrode that collects charges generated in the photoconductor, and a capacitor And a switching element for selectively transmitting a voltage signal charged in the capacitor to the lead-out line. The photoconductor is formed of selenium having photoelectric conversion characteristics to convert X-rays into electrical signals. At this time, an electron-hole pair corresponding to the X-ray is generated in the photoconductor.

The switching element is realized by a thin film transistor (TFT), in which the gate electrode of the TFT is connected to the gate line, and the source electrode of the TFT is connected to the lead-out line. The holes generated by the incidence of X-rays are charged in the capacitor, and the voltage signal charged in the capacitor is read out via the lead-out line and reproduced as an image.

Conventionally, an array substrate manufacturing process of an X-ray detector forms a thin film transistor composed of a gate electrode, an active layer and a source / drain electrode on a substrate, and then forms a photodiode composed of a negative electrode, a photoconductive layer and a positive electrode .

The photodiode is formed by patterning a negative electrode according to a first mask process, forming a positive electrode according to a second mask process, and then forming a photoconductor layer according to a third mask process.

Further, the mask processes are sequentially performed while sequentially forming an insulating film, a metal film, and a protective film on the substrate on which the photodiode is formed. As described above, when the mask process is increased in manufacturing the array substrate, the process becomes complicated.

In addition, if the number of mask processes is increased, there is a problem that the manufacturing cost is increased and the productivity is lowered.

An object of the present invention is to provide a method of manufacturing an array substrate of an X-ray detector in which an electrode and a photoconductive layer are formed by a single mask process when a photodiode is formed, thereby simplifying the process.

According to another aspect of the present invention, there is provided a method of manufacturing an array substrate of an X-ray detector, including: forming a gate line, a switching element including a gate electrode, an active layer, and a source / drain electrode on a substrate; Forming a first interlayer insulating film on the substrate, forming a metal film thereon, and then performing a masking process to form a first electrode electrically connected to the drain electrode in the pixel region, forming a first electrode on the substrate on which the first electrode is formed, Forming a metal film on the photoconductive film using a photoresist pattern as a mask by wet etching to form a metal film on the photoresist film pattern; The second electrode is formed with an undercut structure, and then the dry etching process is performed to obtain the luminous intensity Forming a second interlayer insulating film and a metal film on a substrate on which the second electrode is formed and then performing a mask process to form a lead out line and a power supply line, And forming a protective film.

The method of manufacturing the array substrate of the X-ray detector of the present invention has the effect of simplifying the process by forming the electrode and the photoconductive layer by a single mask process when the photodiode is formed.

1 is a diagram illustrating a pixel structure of an X-ray detector according to the present invention.
FIGS. 2A to 2F are views showing an array substrate manufacturing process of the X-ray detector along the line I-I 'of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a diagram illustrating a pixel structure of an X-ray detector according to the present invention.

1, the pixel structure of the X-ray detector of the present invention includes a gate line 101 and a lead-out line 103 which are arranged in an intersecting relation to define a pixel region, and a gate line 101 and a lead-out line 103 And a photodiode 200 disposed in the pixel region and arranged in parallel with the lead-out line 103 while intersecting the gate line 101 And a power supply line 160. [

The photodiode 200 includes a negative electrode 120, a photoconductive layer 125 and a positive electrode 130. The power source line 160 is parallel to the lead out line 103 in the pixel region And is arranged to overlap with an upper portion of the TFT (Thin Film Transistor).

In the structure of the photodiode 200, the area of the negative electrode 120 is the widest in the pixel region, and the photoconductor layer 125 and the positive electrode 130 are sequentially stacked. The edge of the photoconductive layer 125 is exposed to the outside of the positive electrode 130 and the negative electrode 120 is exposed to the outside of the positive electrode 130, Exposed to the edge of the photoconductive layer 125.

This is because the negative electrode 120 of the photodiode 200, the photoconductive layer 125 and the positive electrode 130 are laminated in the form of a pyramid so that the lateral region of the photodiode 200 has a gentle slope. Such a structure can minimize the leakage current in the lateral direction of the photodiode 200.

The power line 160 is electrically connected to the positive electrode 130 of the photodiode 200. The lead-out line 103 is connected to the source electrode of the thin film transistor As shown in FIG.

FIGS. 2A to 2F are views showing an array substrate manufacturing process of the X-ray detector along the line I-I 'of FIG.

2A to 2F, a photodiode for X-ray detection according to the present invention is formed by depositing a metal film on a substrate 100 and depositing a gate line 101, a gate electrode 101a, a gate pad ) Are simultaneously formed.

When the gate electrode 101a or the like is formed on the substrate 100 as described above, the gate insulating film 112 is formed on the entire surface of the substrate 100, and the semiconductor layer composed of the amorphous silicon film and the doped amorphous silicon film is sequentially And then an active layer 104 is formed on the gate insulating film 112 above the gate electrode 101a by performing a mask process.

As described above, when the active layer 104 is formed on the substrate 100, a source / drain metal film is formed on the entire surface of the substrate 100, and the source / drain electrodes 117a and 117b are formed do.

Then, a first interlayer insulating film 115 is formed on the entire surface of the substrate 100, and a contact hole process is performed to expose the pad region and the drain electrode 117b. Subsequently, any one of molybdenum, aluminum, copper, tungsten, or an alloy thereof is formed on the entire surface of the substrate 100, and the negative electrode 120 is formed in the pixel region by performing the mask process. The negative electrode 120 is electrically connected to the drain electrode 117b.

The negative electrode 120 is formed on the first interlayer insulating film 115. The photoconductive film 225 and the metal film 230 are formed on the entire surface of the substrate 100 as shown in FIG. Are sequentially formed, and then the masking process is performed.

2C and 2D, a photosensitive film is formed on the substrate 100 on which the metal film 230 is formed, and then the photosensitive film pattern 300 is formed by performing exposure and development processes.

The positive electrode 130 is formed on the photoconductive film 225 on the negative electrode 120 by etching the metal film 230 using the photoresist pattern 300 as a mask. The metal layer 230 may be formed of one of transparent conductive materials (ITO, IZO, and ITZO).

At this time, in the present invention, the metal film 230 is over-grained so as to form an undercut structure in the inward direction with respect to the lower side of the edge of the photoresist pattern 300 by controlling the conditions of the wet etching process.

That is, the substrate 100 on which the photoresist pattern 300 is formed is immersed in an etching solution, and the etching time is controlled within a range of 25 seconds to 50 seconds. That is, an etch time is longer than the conventional etch time of 20 seconds to 30 seconds to form an undercut in a range of 0.5 mu m to 1 mu m inward from the lower side edge of the photoresist pattern 300.

Accordingly, the positive electrode 130 formed on the lower side of the photoresist pattern 300 is formed inwardly from the periphery of the lower side edge of the photoresist pattern 300 by 0.5 to 1 μm.

Therefore, the positive electrode 130 is formed to be narrower than the width of the photoresist pattern 300.

When the positive electrode 130 is formed on the photoconductive film 225 as described above, the dry etching process is continuously performed using the photoresist pattern 300 as a mask, as shown in FIG. 2E, (Not shown). The photodiode 200 is completed by the negative electrode 120, the photoconductive layer 125, and the positive electrode 130.

The photoconductive layer 125 is interposed between the negative electrode 120 and the positive electrode 130. The negative electrode 120 has the largest area and the positive photoconductive layer 125 has a positive The area of the water passage going to the electrode 130 is narrowed. Accordingly, in the structure of the photodiode 200 of the present invention, the negative electrode 120, the photoconductive layer 125, and the positive electrode 130 have a pyramidal shape.

As described above, the wet etching process and the dry etching process are sequentially performed in one mask process, and the photodiode 200 is completed. Then, as shown in FIG. 2F, a second interlayer insulating film 116 are formed. Then, a mask process is performed to form contact holes in the source electrode 117a region and the positive electrode 130 region.

Then, a metal film is formed on the entire surface of the substrate 100, and a lead-out line 103 and a power source line 160 are formed according to a mask process.

As described above, when the lead-out line 103 is formed on the substrate 100, the process of opening the photodiode 200 in the pixel region proceeds. Therefore, the second interlayer insulating film 116 formed on the positive electrode 130 of the photodiode 200 is removed, and the positive electrode 130 is exposed to the outside. Then, a protective film 180 is formed on the entire surface of the substrate 100. The protective film 18 is in direct contact with the positive electrode 130 of the photodiode 200 in the pixel region.

As described above, the present invention has an advantage of reducing the number of mask processes by simultaneously forming electrodes and a photoconductive layer by a single mask process at the time of forming a photodiode.

101: gate line 103: lead out line
200: photodiode 160: power supply line
120: Negative electrode 125: Photoconductive layer
130: positive electrode 300: photosensitive film pattern

Claims (7)

Forming a gate line, a switching element including a gate electrode, an active layer and a source / drain electrode on a substrate;
Forming a first interlayer insulating film on the substrate on which the switching element is formed, forming a metal film, and then performing a mask process to form a first electrode electrically connected to the drain electrode in the pixel region;
Sequentially forming a photoconductive film and a metal film on a substrate on which the first electrode is formed, and then forming a photoresist pattern according to a mask process;
Using the photoresist pattern as a mask, the metal film formed on the photoconductive film is subjected to an undercut structure by a wet etching process in which the metal film is over-etched in an inward direction with respect to the lower side of the edge of the photoresist pattern as an etchant solution for 30 seconds to 50 seconds. Two electrodes are formed and then a dry etching process is performed to form a photoconductive layer having a smaller area than that of the first electrode and a wider area than the second electrode, and the first electrode, the photoconductive layer, Forming a layered structure in the form of a pyramid;
Forming a second interlayer insulating film and a metal film on the substrate on which the second electrode is formed, and then performing a mask process to form a lead out line and a power supply line; And
Forming a protective film on the substrate on which the lead-out line is formed,
Wherein the pyramidal shape is such that the edge of the photoconductive layer is exposed to the outside of the second electrode and the edge of the first electrode is exposed to the outside of the photoconductive layer.
delete delete 2. The method of claim 1, wherein the second electrode is formed in an undercut structure having a depth of 0.5 mu m to 1 mu m inward from a lower side edge of the photoresist pattern.
2. The method of claim 1, wherein forming the lead-out line and the power supply line comprises:
And patterning the second interlayer insulating film to expose the second electrode.
6. The method of claim 5, wherein the protective layer is in direct contact with the second electrode.
The method of claim 1, wherein the second electrode is formed of any one of ITO, IZO, and IZTO, which are transparent conductive materials.

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