WO2013143295A1 - Array substrate of x-ray detection device and manufacturing method thereof - Google Patents

Description

 Array substrate of X-ray detecting device and manufacturing method thereof

 Embodiments of the present invention relate to an array substrate of an X-ray detecting apparatus and a method of fabricating the same. Background technique

 The rapid development of thin film transistor technology has led to the application of active matrix X-ray inspection technology. X-ray inspection is mainly for plane inspection. For nearly a century, X-ray imaging has used film to record optical images. The concept of digital medical X-ray imaging has been proposed as early as the early 1970s. With the revolutionary development of digital medical image transmission and image storage transmission systems, the application of digital X-ray imaging technology has made great progress. Unlike digital X-ray imaging with Charge Coupled Device (CCD) and Complementary Metal Oxide Semiconductor (CMOS), planar image detectors provide the advantage of large area detection and no space. , effectively shorten the time-consuming process of traditional X-ray inspection. The digital X-ray imaging system saves up to four times the processing time compared to traditional computer imaging systems, and with high-resolution display panels, it also improves efficiency, diagnostic accuracy, and a film-free medical environment. The active matrix planar detector can be applied to non-destructive testing, and the physical or mechanical properties of the object to be tested can be detected in time without damaging the sample to be tested. It is easy to detect cracks, holes and micros such as 50 microns. Defects are therefore widely used, especially in the electronics, aerospace and automotive industries.

 As shown in Figs. 1 and 2, each pixel region of the array substrate of the conventional X-ray detector generally includes a photodiode sensor device 200 and a thin film transistor device 300. The main function of the photodiode sensor device is to receive light and convert the optical signal into an electrical signal through the photovoltaic effect, and the main function of the thin film transistor device is to control the switch and transmit the electrical signal generated by the photovoltaic effect.

 The existing X-ray detector operates on the principle that when the X-ray 101 is bombarded on the phosphor 102 disposed before the array substrate, the phosphor 102 generates visible light which is incident on the photodiode sensor device 200 of the array substrate. The photodiode sensor device 200 converts the optical signal into an electrical signal by a photovoltaic effect, and the electrical signal is input to the control circuit of the X-ray detector through the switching control of the thin film transistor device 300.

In the prior art, the preparation of the array substrate of the above X-ray detector is completed by using 9 masks, and the main The process steps are as follows.

 Step 101, forming a gate electrode 11 on the base substrate 10 by a first mask process;

 Step 102, depositing a gate insulating layer 12 on the substrate on which the step 101 is completed, and forming an active layer 13 on the array substrate by a second mask process;

 Step 103, forming a channel barrier layer 14 by a third mask process on the substrate on which step 102 is completed;

 Step 104, depositing an ohmic contact layer 29 and a source/drain electrode metal layer on the substrate on which step 103 is completed, and forming a source electrode 15, a drain electrode 16 and a light reflecting layer 17 through a fourth mask process;

 Step 105, forming a N-type semiconductor 18, an I-type semiconductor 19, a P-type semiconductor 20 (ie, a portion of the PIN-type photodiode sensor device) and a transparent electrode 21 through a fifth mask process on the substrate on which the step 104 is completed;

 Step 106, depositing a first passivation layer 22 on the substrate on which step 105 is completed, and forming a first via 23 and a second via 25 on the first passivation layer 22 through a sixth mask process;

 Step 107, forming a pattern of the photomask 27, the bias electrode 24 and the signal line 26 through the seventh mask process on the substrate on which the step 106 is completed;

 Step 108, depositing a second passivation layer 28 on the substrate on which the step 107 is completed, and forming a passivation layer via hole of the signal guiding region by an eighth mask process (not shown);

 Step 109, forming a transparent electrode (not shown) of the signal guiding region through the ninth mask process on the substrate on which the step 108 is completed.

 The above technique has a drawback in that in order to avoid affecting the uniformity of the active layer channel of the formed thin film transistor device when forming the photodiode sensing device, it is necessary to form over the active layer by a single mask process (step 103). A channel barrier layer, which undoubtedly increases the complexity of the manufacturing process of the array substrate, makes the production capacity difficult to increase. In addition, in order to reduce the influence of channel leakage current of the thin film transistor device, the technology also needs to add a metal mask to block the light generated by the X-ray bombardment of the phosphor, which also makes the manufacturing cost cannot be further reduced. Summary of the invention

An embodiment of the present invention provides an array substrate of an X-ray detecting device and a manufacturing method thereof, which are used to solve the problem that the X-ray detecting device array substrate existing in the prior art needs to use another mask process to form a channel block. Layer, which makes the manufacturing process cumbersome, costly, and difficult to upgrade Problems.

 Embodiments of the Invention An array substrate of an X-ray detecting apparatus includes: a thin film transistor device and a photodiode sensor device connected to the thin film transistor device. The thin film transistor device includes: a source and a drain formed over a base substrate; an ohmic layer formed over the source and the drain; an active layer formed over the ohmic layer, the active layer being located The portion between the source and the drain constitutes a channel; a gate insulating layer formed over the active layer and covering the entire substrate; a gate formed over the gate insulating layer and above the active layer.

 For the array substrate, for example, the gate material is preferably a heavy metal or a heavy metal alloy. For the array substrate, for example, the photodiode sensor device includes: a light reflecting layer formed on the gate insulating layer and connected to the drain; a photodiode formed on the light reflecting layer; and a transparent formed on the photodiode An electrode; a bias electrode connected to the transparent electrode above the transparent electrode.

 For the array substrate, for example, the photodiode is a PIN type photodiode.

 In an example, the array substrate of the X-ray detecting apparatus of this embodiment may further include: a first passivation layer formed on the gate electrode and the transparent electrode and covering the entire substrate; formed in the first passivation layer a connection electrode on the first passivation layer; a first via hole connecting the bias electrode and the transparent electrode; a second via hole connecting the connection electrode and the drain; and a connection connecting the electrode and the reflective layer Three vias.

 The method of manufacturing the X-ray detecting device array substrate of the present embodiment includes the steps of forming a thin film transistor device and a photodiode sensor device. Forming a thin film transistor device includes: forming a pattern of a source, a drain, and an ohmic layer by a mask process on a substrate; forming an active layer by a mask process on a substrate forming a pattern of a source, a drain, and an ohmic layer a pattern; a gate insulating layer is formed on the substrate on which the pattern of the active layer is formed; and a pattern of the gate is formed by a mask process on the substrate on which the gate insulating layer is formed.

 For the manufacturing method, for example, forming the photodiode sensor device includes: forming a pattern of the light reflecting layer by the same mask process while forming a pattern of the gate electrode; forming a photodiode by a mask process on the substrate on which the pattern of the light reflecting layer is formed And a pattern of transparent electrodes.

For the manufacturing method, for example, a pattern for forming a photodiode and a transparent electrode includes: depositing an N-type semiconductor layer on the light-reflecting layer; depositing an I-type semiconductor layer on the N-type semiconductor layer; depositing a P-type semiconductor on the I-type semiconductor layer a layer; depositing a transparent electrode layer on the P-type semiconductor layer; forming a pattern of the photodiode and the transparent electrode by a mask process. In one example, the manufacturing method includes the steps of: forming a pattern of the gate and a pattern of the photodiode and the transparent electrode: covering the entire passivation layer on the entire substrate, forming a bias electrode for connecting by using a mask process a first via hole of the transparent electrode and a second via hole and a third via hole for connecting the drain and the light reflecting layer; a pattern of the bias electrode formed by the mask process and a pattern of the connection electrode connecting the drain and the light reflecting layer .

 In the array substrate of the X-ray detecting apparatus of the embodiment of the invention, since the thin film transistor device has a top gate structure and the channel is located under the gate, when the photodiode and the transparent electrode are etched, the gate can be The channel is effectively protected from being affected, eliminating the masking process of the prior art channel barrier layer, simplifying the manufacturing process of the array substrate, and improving the productivity; in addition, the top gate type thin film transistor The gate of the device can effectively block the light that is irradiated to the channel, so that the leakage current of the channel is greatly reduced, so that no additional mask is needed, which simplifies the production process and further reduces the production cost. DRAWINGS

 In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. It is obvious that the drawings in the following description relate only to some embodiments of the present invention, and are not intended to limit the present invention. .

 1 is a schematic cross-sectional structural view of an array substrate of a prior art X-ray detecting device;

 2 is a schematic structural view of a prior art X-ray detecting device detecting principle;

 3 is a schematic cross-sectional structural view of an array substrate of an X-ray detecting device of the present invention;

 4 is a top view of the first masking process of the present invention after exposure and development;

 Figure 5 is a cross-sectional view showing the first masking process of the present invention after exposure and development;

 6 is a top view of the first mask process after etching according to the present invention;

 7 is a cross-sectional view taken along line A-A of FIG. 6 after etching for the first mask process of the present invention; FIG. 8 is a plan view of the second mask process after etching according to the present invention;

 9 is a cross-sectional view taken along line A-A of FIG. 8 after etching of the second mask process of the present invention; FIG. 10 is a plan view of the third mask process after etching according to the present invention;

 11 is a cross-sectional view taken along line A-A of FIG. 10 after etching of the third mask process of the present invention; FIG. 12 is a plan view of the fourth mask process after etching according to the present invention;

Figure 13 is a cross-sectional view taken along line BB of Figure 12 after etching of the fourth mask process of the present invention; Figure 14 is a top plan view of the fifth mask process after etching according to the present invention;

 Figure 15 is a top plan view of the sixth mask process after etching according to the present invention;

 16 is a cross-sectional view showing the seventh mask process (signal guiding region connecting data line vias) after etching according to the present invention;

 17 is a cross-sectional view showing the seventh mask process (signal guiding region connecting gate line via) after etching according to the present invention;

 18 is a cross-sectional view showing an eighth mask process (a transparent electrode connected to a signal guiding region and a data line) after etching according to the present invention;

 Figure 19 is a cross-sectional view showing the eighth masking process (transparent electrode in which the signal guiding region is connected to the gate line) of the present invention.

 Description of the reference signs:

 10 base substrate 11 gate 12 gate insulation

 13 active layer 14 channel barrier 15 source

 16 Drain 17 Reflective layer 18 N-type semiconductor

 19 I type semiconductor 20 P type semiconductor 21 transparent electrode

 22 first passivation layer 23 first via 24 bias electrode

 25 second via 26 signal line 27 mask

 28 second passivation layer 29 ohmic contact layer 101 X-ray

 102 Phosphor 200 Photodiode Sensors 300 Thin Film Transistors

50 base substrate 51 gate 52 gate insulation

 53 active layer 69 ohm layer 55 source

 56 Drain 57 Reflective layer 58 N-type semiconductor

 59 I-type semiconductor 60 P-type semiconductor 61 transparent electrode

 62 first passivation layer 63 first via hole 64 bias electrode

 65 second via 70 third via 71 connecting electrode

 68 second passivation layer 51a gate line 5556a data line

 Transparent electrode of signal guiding area 5556 source/drain electrode metal layer

Photoresist 690 ohm layer (before etching) The technical solutions of the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the described embodiments of the present invention without departing from the scope of the invention are within the scope of the invention.

 Unless otherwise defined, technical terms or scientific terms used herein shall be of the ordinary meaning understood by those of ordinary skill in the art to which the invention pertains. The words "first", "second" and similar terms used in the specification and claims of the present invention do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the words "a" or "an" do not denote a quantity limitation, but rather mean that there is at least one. The words "including" or "comprising", etc., are intended to mean that the elements or objects preceding "including" or "comprising" are intended to encompass the elements or Component or object. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right", etc. are only used to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationship may also change accordingly.

 In order to solve the technical problem that the X-ray detecting device array substrate existing in the prior art needs to use another mask process to form the channel barrier layer, the manufacturing process is cumbersome, the cost is high, and the productivity is difficult to be improved, the embodiment of the present invention An array substrate of an X-ray detecting device and a method of manufacturing the same are provided.

 The array substrate of the embodiment of the present invention includes a plurality of gate lines and a plurality of data lines, the gate lines and the data lines crossing each other thereby defining a plurality of pixel units arranged in a matrix, each of the pixel units including a thin film transistor as a switching element The device and the photodiode sensor device connected to the thin film transistor device. For example, the gate of the thin film transistor of each pixel is electrically connected or integrally formed with the corresponding gate line, the source is electrically connected or integrally formed with the corresponding data line, and the drain is connected to the corresponding photodiode sensor device. The following description is mainly made for a single or a plurality of pixel units, but other pixel units may be formed identically.

As shown in FIG. 3, each pixel unit of the array substrate of the X-ray detecting apparatus of the embodiment of the present invention includes a thin film transistor device 300 and a photodiode sensor device 200 connected to the thin film transistor device. The thin film transistor device 300 includes: a source 55 and a drain 56 formed over the base substrate 50; an ohmic contact layer 29 formed over the source 55 and the drain 56; formed in the ohmic contact layer An active layer 53 over 29; a gate insulating layer 52 formed over the active layer 53 and covering the entire substrate; a gate 51 formed over the gate insulating layer 52 and above the active layer 53. The base substrate 50 may be a glass substrate, a plastic substrate, or another substrate. A portion of the active layer 53 between the source 55 and the drain 56 constitutes a channel of the thin film transistor.

 The gate electrode 51 is preferably made of a heavy metal or a heavy metal alloy which is difficult to penetrate by X-rays, such as copper, lead or copper-lead alloy.

 In the embodiment shown in FIG. 3, the photodiode sensor device 200 includes: a light reflecting layer 57 formed on the gate insulating layer 52 and connected to the drain electrode 56 of the thin film transistor; and a photodiode formed on the light reflecting layer 57. A transparent electrode 61 formed on the photodiode; a bias electrode 64 connected to the transparent electrode 61 above the transparent electrode 61.

 The light reflecting layer 57 formed on the gate insulating layer 52 is made of the same material as the gate electrode 51 and formed in the same mask patterning process as the gate electrode 51. The photodiode may be a MIS type photodiode or a PIN type photodiode, etc., preferably a PIN type photodiode. A PIN type photodiode (P-type semiconductor 60, I-type semiconductor 59, N-type semiconductor 58) is a PN junction between two semiconductors, or a region adjacent to a junction between a semiconductor and a metal, in the P region and the N region A type I photodetector that generates a type I (intrinsic) layer and absorbs light radiation to generate a photocurrent. PIN type photodiodes have the advantages of small junction capacitance, short transit time, and high sensitivity.

 The array substrate of the embodiment shown in Fig. 3 further includes a first passivation layer 62 and a second passivation layer 68. The first passivation layer 62 is formed over the gate electrode 51 and the transparent electrode 61 and covers the entire substrate. A first via 63 connecting the bias electrode 64 and the transparent electrode 61, a second via 65 connecting the connection electrode 71 and the drain 56, and a connection connection electrode 71 and a light reflecting layer 57 are opened in the first passivation layer 62. The third via 70. That is, the connection electrode 71 formed over the first passivation layer 62 connects the drain 56 and the light-reflecting layer 57 through the second via 65 and the third via 70. A second passivation layer 68 is formed over the first passivation layer 62 and covers the entire array substrate. The transparent electrode 61a of the peripheral signal guiding region of the array substrate is connected to the data line 5556a through the via hole penetrating through the first passivation layer 62, the second passivation layer 68 and the gate insulating layer 52, and passes through the first passivation layer 62. A via penetrating through the second passivation layer 68 is connected to the gate line 51a. The passivation layer can be prepared by using an inorganic insulating film such as silicon nitride or the like, or an organic insulating film such as a resin material.

Above the array substrate of the X-ray detecting device of the embodiment, for example, a phosphor is disposed, and the phosphor emits fluorescence when irradiated with X-rays, and the fluorescence can be photoelectrically emitted by the corresponding pixel unit in the array substrate. The diode photosensitive element is detected and recorded.

 In the array substrate of the X-ray detecting device of the embodiment, since the thin film transistor device has a top gate structure and the channel is located under the gate, the gate can effectively block the light that is irradiated to the channel, so that the channel leakage current is greatly reduced. Thus, there is no need to additionally provide a photomask forming a barrier layer. Therefore, the present embodiment further reduces the production cost while simplifying the production process.

 As shown in FIG. 4 to FIG. 19, the array substrate of the X-ray detecting apparatus of the present embodiment can be formed by using eight mask production processes in total, and the main implementation process includes the following steps.

 Step 201: sequentially depositing a source/drain electrode metal layer 5556 and an ohmic layer (before etching) 690 on the base substrate; then, forming a pattern of the source 55, the drain 56, and the ohmic layer 69 by a first masking process. As shown in Figure 4-7.

 The source-drain electrode metal layer 5556 can be deposited by magnetron sputtering, and can be an aluminum-niobium alloy (AlNd), aluminum (A1), copper (Cu), molybdenum (Mo), molybdenum-tungsten alloy (MoW) or chromium ( The single layer film of Cr) may also be a composite film composed of any combination of these metal materials. The ohmic layer 690 沉积 is deposited by chemical vapor deposition and may be made of a doped semiconductor (n+a-Si). In the etching, the ohmic layer (before etching) 690 is dry etched, and then the source and drain electrode metal layer 5556 is wet etched.

 For the metal layer, it is usually deposited by physical vapor deposition (e.g., magnetron sputtering), and the pattern is formed by wet etching. For the non-metal layer, it is usually deposited by chemical vapor deposition, and patterned by dry etching. Each mask process includes, for example, substrate cleaning, photoresist coating, exposure and development, etching, photoresist stripping, and the like, which will not be described below.

 Step 202: forming a pattern of the active layer 53 and its channel by a second mask process on the substrate on which step 201 is completed, as shown in FIGS. The material of the active layer is, for example, amorphous silicon, which is formed by wet etching after deposition by a chemical weather deposition method.

 Step 203: sequentially depositing a gate insulating layer 52 and a gate metal layer on the substrate on which the step 202 is completed and forming a pattern of the gate electrode 51 and the light reflecting layer 57 by a third mask process, as shown in FIGS. The material of the gate insulating layer 52 is, for example, silicon nitride; the gate electrode 51 and the light reflecting layer 57 are formed of the same material and formed in the same masking process, and the material thereof may be a heavy metal or a heavy metal alloy such as copper-lead alloy.

Step 204: sequentially deposit an N-type semiconductor layer (n+a-Si), an I-type semiconductor layer (a-Si), a P-type semiconductor layer (p+a-Si), and a transparent electrode layer on the substrate on which step 203 is completed. Through the fourth time The mask process forms a pattern of a PIN type photodiode (P-type semiconductor 60, I-type semiconductor 59, N-type semiconductor 58) and a transparent electrode 61 as shown in FIGS. 12-13. The material of the transparent electrode layer may be indium tin oxide (ITO) or the like.

 Step 205: depositing a first passivation layer 62 on the substrate on which the step 204 is completed, and forming a first via 63 for connecting the bias electrode 64 and the transparent electrode 61 by a fifth mask process and for connecting the drain The pattern of the second via 65 and the third via 70 of the pole 56 and the light reflecting layer 57 is as shown in FIG.

 Step 206: depositing a bias electrode metal on the substrate on which step 205 is completed, forming a pattern of the bias electrode 64 by the sixth mask process, and having the same material as the bias electrode 64, connecting the drain electrode 56 and the light reflecting layer 57. The pattern of the connection electrode 71 is as shown in FIG.

 Step 207: deposit a second passivation layer 68 on the substrate on which the step 206 is completed, and signal the periphery of the panel through the seventh mask process; 1: the early contact region is formed to connect the transparent electrode 61 with the gate line 51a and the data line 5556a. The pattern of the signal guiding area vias is shown in Figure 16-17.

 Step 208: forming a pattern of the transparent electrode 61a of the signal guiding region (covering the signal guiding region via hole) through the eighth mask process on the substrate on which the step 207 is completed, to protect the metal at the via from corrosion, as shown in FIG. - Figure 19 is shown.

 It can be seen from the production process of the array substrate of the X-ray detecting device of the embodiment that since the thin film transistor device uses a top gate structure, the channel is located under the gate, and the gate can effectively block the light, and therefore, the photoelectric is performed. When the diode and the transparent electrode are etched, the gate can effectively protect the channel from being affected. Therefore, the present embodiment omits the mask process formation process of the channel barrier layer in the prior art, and the mask process can be used eight times in total, which simplifies the manufacturing process of the array substrate and improves the production performance. In addition, since the gate of the fabricated top-gate thin film transistor device can effectively block light, the channel leakage current is greatly reduced, and there is no need to additionally provide a photomask, which further reduces the production cost while simplifying the production process.

 It is apparent that the above description is only for the purpose of description and not for the scope of the invention, and the scope of the invention is defined by the appended claims.

Claims

Claim An array substrate for an X-ray detecting device, comprising: a thin film transistor device and a photodiode sensor device connected to the thin film transistor device,  The thin film transistor device includes:  a source and a drain formed on the substrate;  An ohmic layer formed over the source and the drain;  An active layer formed on the ohmic layer, the active layer forming a channel between the source and the drain;  a gate insulating layer formed over the active layer and covering the entire of the base substrate; a gate formed over the gate insulating layer and above the active layer.  The array substrate according to claim 1, wherein the material of the gate is a heavy metal or a heavy metal alloy.  The array substrate of claim 1 , wherein the photodiode sensing device comprises: a reflective layer formed on the gate insulating layer and connected to the drain;  a photodiode formed on the reflective layer;  a transparent electrode formed on the photodiode;  a bias electrode connected to the transparent electrode above the transparent electrode.  The array substrate according to claim 3, wherein the photodiode is a PIN type photodiode.  The array substrate according to claim 3 or 4, further comprising:  Forming a first passivation layer over the gate and the transparent electrode and covering the entire substrate;  a connection electrode formed over the first passivation layer;  a first via hole connecting the bias electrode and the transparent electrode, a second via connecting the connection electrode and the drain, and a connection connection electrode in the first passivation layer And a third via of the reflective layer.  6. A method of fabricating an array substrate of an X-ray detecting device, comprising the steps of forming a thin film transistor device and a photodiode sensor device, Wherein the forming the thin film transistor device comprises: Forming a pattern of a source, a drain, and an ohmic layer on a base substrate by a mask process; forming a pattern of the active layer by a mask process on a base substrate forming a pattern of the source, drain, and ohmic layers ;  Forming a gate insulating layer on the base substrate forming the pattern of the active layer;  A pattern of a gate electrode is formed by a mask process on a base substrate on which the gate insulating layer is formed. The method of manufacturing an array substrate according to claim 6, wherein the material of the gate is a heavy metal or a heavy metal alloy.  The method of manufacturing an array substrate according to claim 6 or 7, wherein the forming the photodiode sensor device comprises:  A pattern of the light-reflecting layer is formed by the same masking process while forming the pattern of the gate electrode; a pattern of the photodiode and the transparent electrode is formed by a mask process on the base substrate on which the pattern of the light-reflecting layer is formed.  9. The method of fabricating an array substrate according to claim 8, wherein the pattern forming the photodiode and the transparent electrode comprises:  Depositing an N-type semiconductor layer on the reflective layer;  Depositing an I-type semiconductor layer on the N-type semiconductor layer;  Depositing a P-type semiconductor layer on the I-type semiconductor layer;  Depositing a transparent electrode layer on the P-type semiconductor layer;  A pattern of the photodiode and the transparent electrode is formed by a mask process.  The method of manufacturing the array substrate according to claim 8, further comprising: after forming the pattern of the gate and the pattern of the photodiode and the transparent electrode:  Covering the first passivation layer on the entire substrate, forming a first via for connecting the bias electrode and the transparent electrode through a mask process and respectively for connecting the drain and the drain a second via and a third via of the reflective layer;  A pattern of the bias electrode and a pattern connecting the drain and the connection electrode of the light reflecting layer are formed by a mask process.