CN100380629C - Method for manufacturing pixel structure - Google Patents

Abstract

A method for fabricating a pixel structure comprises forming a source/drain on a substrate by using a first mask; repeatedly using a second mask twice to respectively form a transparent conducting layer and a channel layer on the substrate, wherein the transparent conducting layer covers part of the source/drain electrode and is electrically connected with the source/drain electrode, and the pattern of the transparent conducting layer is complementary with the pattern of the channel layer; forming a dielectric layer on the substrate to cover the transparent conductive layer and the channel layer; a gate is formed on the dielectric layer using a third mask. Therefore, the pixel structure has lower manufacturing cost.

Description

How to make pixel structure

technical field

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a pixel structure.

Background technique

With the advancement of modern video information technology, various displays have been widely used on the display screens of consumer electronic products such as mobile phones, notebook computer digital cameras and personal digital assistants (Personal Digital Assistant, PDA). Among these displays, liquid crystal displays (Liquid Crystal Display, LCD) and organic electroluminescent displays (Organic Light Emitting Diode, OLED) have the advantages of light weight, small size and low power consumption, making them the mainstream in the market. Whether it is a liquid crystal display or an organic electroluminescent display, the manufacturing process includes forming a pixel array on a substrate by semiconductor technology. By correspondingly adjusting the colors displayed by each pixel in the pixel array, the display can generate an image.

1A-1E are schematic cross-sectional views of a known formation process of a pixel structure. Please refer to FIG. 1A , first a source 110 /drain 120 is formed on a substrate 50 by using a first photo mask 210 . Referring to FIG. 1B , a second mask 220 is then used to form a channel layer (channel) 130 on the substrate 50 and part of the source 110 /drain 120 . Please refer to FIG. 1C, a first dielectric layer (dielectric layer) 140 is formed on the substrate 50 to cover the source 110/drain 120 and the channel layer 130, and a third mask 230 is used to cover the first dielectric layer. A gate 150 is formed on layer 140 . Please refer to FIG. 1D, and then form a second dielectric layer 160 on the first dielectric layer 140 and the gate 150, and use a fourth mask 240 in the first dielectric layer 140 and the second dielectric layer 160 A contact window 170 is formed to expose a portion of the drain 120 . Please refer to FIG. 1E, finally utilize a fifth mask 250 to form a transparent conductive layer 180 on the second dielectric layer 160, wherein part of the transparent conductive layer 180 is filled into the contact opening 170, so that the transparent conductive layer 180 is electrically conductive. Connect to drain 120 . So far, the fabrication of the pixel structure 100 is completed.

Following the above, one of the main costs of manufacturing the pixel structure 100 is the manufacturing cost of the mask. However, in the prior art, five different masks must be used to form the pixel structure 100 , so the manufacturing cost of the pixel structure 100 cannot be reduced. In particular, as the size of the substrate increases, a mask with a larger area must be used to manufacture the pixel structure 100 , which further increases the manufacturing cost of the pixel structure 100 .

Contents of the invention

The purpose of the present invention is to provide a method for manufacturing a pixel structure, which can reduce the manufacturing cost of the pixel structure.

To achieve the above or other purposes, the present invention proposes a method for manufacturing a pixel structure, the steps of which include forming a source/drain on a substrate using a first mask; forming a transparent conductive layer and a channel layer, wherein the transparent conductive layer covers part of the source/drain and is electrically connected to the source/drain, and the pattern of the transparent conductive layer is complementary to the pattern of the channel layer; A dielectric layer is formed on the substrate to cover the transparent conductive layer and the channel layer; a grid is formed on the dielectric layer by using a third mask.

In one embodiment of the present invention, the step of forming the transparent conductive layer and the channel layer includes forming a transparent conductive material layer on the substrate to cover the source/drain electrodes; forming a first-type patterned photoresist layer; using the first-type patterned photoresist layer as a mask to remove part of the transparent conductive material layer to form a transparent conductive layer; removing the first-type patterned photoresist layer . Form a channel material layer on the substrate; use a second mask to form a second-type patterned photoresist layer on the channel material layer, wherein the second-type patterned photoresist layer and the first-type patterned photoresist layer The types of the resist layer are different; using the second-type patterned photoresist layer as a mask to remove part of the channel material layer to form a channel layer; removing the second-type patterned photoresist layer.

In an embodiment of the present invention, the above-mentioned first-type patterned photoresist layer is a positive-type photoresist, and the second-type patterned photoresist layer is a negative-type photoresist.

In an embodiment of the present invention, the above-mentioned first-type patterned photoresist layer is a negative-type photoresist, and the second-type patterned photoresist layer is a positive-type photoresist.

In one embodiment of the present invention, the step of forming the transparent conductive layer and the channel layer includes forming a channel material layer on the substrate to cover the source/drain electrodes; forming a second-type patterned photoresist layer; using the second-type patterned photoresist layer as a mask to remove part of the channel material layer to form a channel layer; removing the second-type patterned photoresist layer . Form a transparent conductive material layer on the substrate; use a second mask to form a first-type patterned photoresist layer on the transparent conductive layer, wherein the first-type patterned photoresist layer and the second-type patterned photoresist layer The types of the adhesive layer are different; using the first-type patterned photoresist layer as a mask to remove part of the transparent conductive material layer to form a transparent conductive layer; removing the first-type patterned photoresist layer.

In an embodiment of the present invention, the above-mentioned first-type patterned photoresist layer is a positive-type photoresist, and the second-type patterned photoresist layer is a negative-type photoresist.

In an embodiment of the present invention, the above-mentioned first-type patterned photoresist layer is a negative-type photoresist, and the second-type patterned photoresist layer is a positive-type photoresist.

In an embodiment of the present invention, the step of forming the source/drain further includes forming an ohmic contact layer on the source/drain by using the first mask.

In an embodiment of the present invention, after the above step of forming the gate, it further includes forming a patterned photoresist layer on the dielectric layer and the gate using the first mask; using the patterned photoresist layer as a mask removing part of the dielectric layer to form a patterned dielectric layer, wherein the patterned dielectric layer exposes part of the transparent conductive layer; removing the patterned photoresist layer.

In an embodiment of the present invention, after the above step of forming the gate, it further includes forming a photoresist layer on the dielectric layer and the gate, wherein the gate and the source/drain partially overlap; /Drain and gate are used as a mask to pattern the photoresist layer to form a patterned photoresist layer; use the patterned photoresist layer as a mask to remove part of the dielectric layer to form a pattern patterning the dielectric layer, wherein the patterned dielectric layer exposes part of the transparent conductive layer; removing the patterned photoresist layer.

To sum up, compared with the prior art that requires five masks to fabricate the pixel structure, the present invention only uses three masks to complete the fabrication of the pixel structure, so the fabrication cost of the pixel structure can be reduced.

Description of drawings

1A-1E are schematic cross-sectional views of a known formation process of a pixel structure.

2A-2M are schematic cross-sectional views of the formation process of the pixel structure according to an embodiment of the present invention.

3A-3C are schematic cross-sectional views of a process for removing a dielectric layer according to an embodiment of the present invention.

4A-4D are schematic cross-sectional views of a process of removing a dielectric layer according to another embodiment of the present invention.

FIG. 5A is a schematic diagram of a terminal structure according to an embodiment of the invention.

Fig. 5B is a schematic cross-sectional view along line A-A' in Fig. 5A.

Symbol Description:

50, 60: Substrate

100: pixel structure

110: source 210: first mask

120: drain 220: second mask

130: channel layer 230: third mask

140: the first dielectric layer 240: the fourth mask

150: gate 250: fifth mask

160: second dielectric layer

170: contact window opening

180: transparent conductive layer

300, 300a, 300b: pixel structure

310: source 410: first mask

320: drain 420: second mask

330: ohmic contact layer 430: third mask

340: transparent conductive layer

350: channel layer

360: dielectric layer

362, 364: patterned dielectric layer

370: Gate

510: conductive layer 520, 580: photoresist layer

522, 570, 582: patterned photoresist layer

530: transparent conductive material layer 540: first type patterned photoresist layer

550: channel material layer 560: second type patterned photoresist layer

600: Terminal structure 610: Wire

620: transparent wire 630: amorphous silicon layer

θ: angle

Detailed ways

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

2A-2M are schematic cross-sectional views of the formation process of the pixel structure according to an embodiment of the present invention. Please refer to FIG. 2A. First, a conductive layer 510 is formed on a substrate 60, wherein the material of the conductive layer 510 can be selected from aluminum (Al), molybdenum (Mo), molybdenum nitride (MoN), titanium (Ti), nitride Titanium (TiN), chromium (Cr), chromium nitride (CrN), or combinations thereof. In this embodiment, the conductive layer 510 can be a three-layer stacked structure of titanium/aluminum/titanium nitride, wherein the preferred thickness of aluminum is between 500 Ȧ and 2000 Ȧ, and the preferred thickness of titanium or titanium nitride The thickness is between 300 Ȧ˜1000 Ȧ. Next, a photoresist layer 520 is formed on the conductive layer 510 , and a first mask 410 is used as a shield to perform an exposure process on the photoresist layer 520 .

Referring to FIG. 2B , the photoresist layer 520 is then developed to form a patterned photoresist layer 522 . In this embodiment, the type of the photoresist layer 520 can be a negative photoresist (negative photoresist), wherein the exposed part of the photoresist layer 520 will not be developed to form a patterned photoresist layer. 522. Referring to FIG. 2C , an etching process is performed using the patterned photoresist layer 522 as a mask to remove part of the conductive layer 510 to form the source 310 /drain 320 . Please refer to FIG. 2D, and then perform a stripper process to remove the patterned photoresist layer 522 to complete the manufacturing process of forming the source electrode 310/drain electrode 320 on the substrate 60 with the first mask 410 (as shown in FIG. 2A ~2D). Please refer to FIG. 2E, in order to enable the source 310/drain 320 to have better electrical characteristics, the present invention, for example, forms an ohmic contact layer 330 on the source 310/drain 320 with a first mask 410. The process is similar to the aforementioned steps, and will not be repeated here. In this embodiment, the material of the ohmic contact layer 330 may be heavily doped amorphous silicon (n+amorphous silicon, n+α-Si), and its preferred thickness is between 500 Ȧ-4000 Ȧ. And the present invention can also form the ohmic contact layer 330 by other processes. For example, after forming the conductive layer 510 (as shown in FIG. 2A ), an ohmic contact material layer (not shown) can be formed on the conductive layer 510, and then a photoresist layer 520 can be formed on the ohmic contact material layer. . Exposure and development processes are performed on the photoresist layer 520 to form a patterned photoresist layer 522 . Afterwards, performing an etching process to remove part of the ohmic contact material layer to form the ohmic contact layer 330 , and remove part of the conductive layer 510 to form the source electrode 310 /drain electrode 320 . Finally, a stripping process is performed to remove the patterned photoresist layer 522 (as shown in FIG. 2E ).

Please refer to FIG. 2F, and then form a transparent conductive material layer 530 on the substrate 60 to cover the source electrode 310/drain electrode 320, wherein the material of the transparent conductive material layer 530 can be indium tin oxide (Indium TinOxide, ITO) or indium zinc oxide (Indium Zinc Oxide, IZO), and its preferred thickness is between 500 Ȧ～3000 Ȧ. Then use a second mask 420 to form a first-type patterned photoresist layer 540 on the transparent conductive material layer 530, wherein the type of the first-type patterned photoresist layer 540 can be a positive photoresist (positive photoresist). Please refer to FIG. 2G , and then use the first-type patterned photoresist layer 540 as a mask to remove part of the transparent conductive material layer 530 to form a transparent conductive layer 340, wherein the transparent conductive layer 340 covers part of the source electrode 310/drain electrode 320 , and electrically connected to the source 310 /drain 320 . Please refer to FIG. 2H , and then perform a stripping process to remove the first-type patterned photoresist layer 540 to complete the manufacturing process of forming a transparent conductive layer 340 on the substrate 60 with the second mask 420 (as shown in FIGS. 2F-2H . Show).

Please refer to FIG. 2I, then a channel material layer 550 is formed on the substrate 60 to cover the source/drain electrodes 310, 320 and the transparent conductive layer 340, wherein the material of the channel material layer 550 can be amorphous silicon (amorphous silicon) , α-Si), and its preferred thickness is between 500 Ȧ～4000 Ȧ. Next, the second mask 420 is used to form a second-type patterned photoresist layer 560 on the channel material layer 550 , wherein the type of the second-type patterned photoresist layer 560 may be a negative-type photoresist. Please refer to FIG. 2J , and then use the second-type patterned photoresist layer 560 as a mask to remove part of the channel material layer 550 to form a channel layer 350, wherein the channel layer 350 covers part of the source 310 and part of the drain 320 , and the pattern of the channel layer 350 is complementary to the pattern of the transparent conductive layer 340 . Please refer to FIG. 2K, and then perform a film stripping process to remove the second type patterned photoresist layer 560 to complete the manufacturing process of forming the channel layer 350 on the substrate 60 with the second mask 420 (as shown in FIGS. 2I-2K Show).

The present invention does not limit the sequence of forming the transparent conductive layer 340 and the channel layer 350 . That is to say, in the present invention, the manufacturing process shown in FIGS. 2I-2K can be completed first to form the channel layer 350 , and then the manufacturing process shown in FIGS. 2F-2H can be completed to form the transparent conductive layer 340 . In addition, the present invention can exchange the types of the first-type patterned photoresist layer 540 and the second-type patterned photoresist layer 560, that is, the type of the first-type patterned photoresist layer 540 is a negative photoresist layer. resist, and the type of the second-type patterned photoresist layer 560 is positive-type photoresist. Certainly, in this embodiment, the present invention also needs to correspondingly adjust the light-transmitting area and the light-impermeable area of the second mask 420 . Those who are familiar with this technique can easily deduce the above-mentioned situations, so they will not be illustrated here.

Referring to FIG. 2L, a dielectric layer 360 is then formed on the substrate 60, wherein the material of the dielectric layer 360 can be silicon nitride (SiNx), silicon oxide (SiOx) or silicon oxynitride (SiOxNy). In addition, the dielectric layer 360 can be formed by plasma enhanced chemical vapor deposition (PlasmaEnhanced Chemical Vapor Deposition, PECVD), and its preferred thickness is between 1500 Ȧ-4000 Ȧ, and its preferred growth The temperature should not exceed 300°C.

Please refer to FIG. 2M, and then use a third mask 430 to form a gate 370 on the dielectric layer 360, wherein the detailed manufacturing process is similar to the aforementioned steps (the process steps shown in FIGS. 2A-2D ), and will not be repeated here. repeat. In addition, the material of the gate 370 can be selected from aluminum, molybdenum, molybdenum nitride, titanium, titanium nitride, chromium, chromium nitride or combinations thereof. In this embodiment, the gate 370 may be a titanium nitride/aluminum/titanium/titanium nitride four-layer stack structure, wherein the preferred thickness of aluminum is between 500 Ȧ and 2000 Ȧ, and titanium or nitride The preferred thickness of titanium is between 300 Ȧ˜1000 Ȧ.

Following the above, the steps up to this point are to complete the fabrication of the pixel structure 300 of the present invention. Since the present invention only uses three masks including the first mask 410 , the second mask 420 and the third mask 430 to complete the fabrication of the pixel structure 300 , the fabrication cost of the pixel structure 300 can be reduced. In the present invention, the transparent conductive layer 340 and the channel layer 350 are respectively formed by using the second mask 420 and carrying out a photolithography process with a positive photoresist and a negative photoresist, so as to reduce the number of masks used.

In order to make the pixel structure 300 have a better light-transmitting effect, the present invention can further remove part of the dielectric layer 360 above the transparent conductive layer 340 . 3A-3C are schematic cross-sectional views of a process for removing a dielectric layer according to an embodiment of the present invention, wherein FIG. 3A is a process following FIG. 2M . Referring to FIG. 3A , firstly, a patterned photoresist layer 570 is formed on the dielectric layer 360 and the gate 370 using the first mask 410 . Please refer to FIG. 3B, and then use the patterned photoresist layer 570 as a mask to perform an etching process to remove part of the dielectric layer 360 to form a patterned dielectric layer 362, wherein the patterned dielectric layer 362 exposes a portion of the transparent conductive layer. Layer 340.

Following the above, in this embodiment, the etching process may be a dry etching process with a high selectivity ratio, so as to prevent the gate 370 from being removed simultaneously during the etching process. Specifically, the etching gas may be composed of sulfur fluoride (SF ₆ )/sulfur fluoride (CF ₄ )/nitrogen (N ₂ )/oxygen (O ₂ ), and when the operating pressure is between 1-5 mTorr (mTorr), the etching selectivity ratio of the dielectric layer 360 to the gate 370 is between 2.0˜3.0, which ensures that the structure of the gate 370 will not be damaged during the etching process. Referring to FIG. 3C , a stripping process is then performed to remove the patterned photoresist layer 570 to complete the fabrication process of the pixel structure 300 a with the patterned dielectric layer 362 (as shown in FIGS. 3A-3C ).

The above-mentioned process of removing the dielectric layer 360 is completed by using the first mask 410 in combination with a high-selectivity etching process, so there is no need to add additional masks, thereby reducing the manufacturing cost of the pixel structure 300a. In addition, the present invention is not limited to removing part of the dielectric layer 360 above the transparent conductive layer 340 in the above manner, and another example will be given below for illustration.

4A-4C are schematic cross-sectional views of a process for removing a dielectric layer according to another embodiment of the present invention, wherein FIG. 4A is a process following FIG. 2M . Please refer to FIG. 4A. First, a photoresist layer 580 is formed on the dielectric layer 360 and the gate 370, and the photoresist layer 580 is shielded from the bottom of the substrate 60 with the source 310/drain 320 and the gate 370. Exposure process, which is commonly known as back exposure technology (Back light exposure technology). In order to improve the quality and effect of exposure, in this embodiment, the preferred wavelength of the exposure light source is between 100-450 nm, and the corresponding photoresist layer 580 is a photoresist with high sensitivity. In addition, the material of the bottom layer of the source/drain 310, 320 and gate 370 structure can be titanium nitride for anti-reflection, so that the standing wave phenomenon can be reduced during the exposure process and the exposure effect can be improved. The source 310 /drain 320 may partially overlap with the gate 370 , and the preferred overlapping range is 1.5 μm.

Referring to FIG. 4B , the photoresist layer 580 is then developed to form a patterned photoresist layer 582 . In this embodiment, the photoresist layer 580 is positive photoresist, and the unexposed part of the photoresist layer 580 will not be developed to form a patterned photoresist layer 582 . In addition, the formation angle θ of the patterned photoresist layer 582 preferably ranges between 45° and 80°. Please refer to FIG. 4C, and then use the patterned photoresist layer 582 as a mask to perform an etching process to remove part of the dielectric layer 360 to form a patterned dielectric layer 364, wherein the patterned dielectric layer 364 exposes a portion of the transparent conductive layer. Layer 340. Referring to FIG. 4D , a stripping process is then performed to remove the patterned photoresist layer 582 to complete the fabrication process of the pixel structure 300b with the patterned dielectric layer 364 (as shown in FIGS. 4A˜4D ).

In the above-mentioned process of removing the dielectric layer 360, the source 310/drain 320 and the gate 370 are used as shields to perform the back exposure process, so there is no need to add additional masks, so the pixel structure 300b can be reduced. production cost. In addition, the present invention can also form a terminal structure by using only three masks, which will be described below with reference to figures.

FIG. 5A is a schematic diagram of a terminal structure according to an embodiment of the present invention, and FIG. 5B is a schematic cross-sectional view along line A-A' in FIG. 5A. Please refer to FIG. 5A and FIG. 5B at the same time. The terminal structure 600 of the present invention is mainly composed of a wire 610, a transparent wire 620 and an amorphous silicon layer 630, wherein the wire 610 is electrically connected to the transparent wire 620, and is suitable for for transmitting electrical signals. The wire 610 can be formed simultaneously during the process of forming the source 310/drain 320 (as shown in FIGS. 2A-2D ), and the transparent wire 620 can be formed simultaneously during the process of forming the transparent conductive layer 340 (as shown in FIGS. 2F-2H ). , and the amorphous silicon layer 630 may be formed simultaneously during the process of forming the channel layer 350 (as shown in FIGS. 2I˜2K ).

In summary, the manufacturing method of the pixel structure of the present invention has at least the following advantages:

1. Compared with the prior art that needs to use five masks to fabricate the pixel structure, the present invention only needs to use three masks to complete the fabrication of the pixel structure, so the fabrication cost of the pixel structure can be reduced.

2. The manufacturing method of the pixel structure of the present invention is compatible with the existing process, so no additional process equipment is needed.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of an invention shall be determined by the scope of the patent application.

Claims (10)

1. A method for making a pixel structure, comprising: forming a source/drain on a substrate by using a first mask; Reusing a second mask twice to form a transparent conductive layer and a channel layer respectively on the substrate, wherein the transparent conductive layer covers part of the source/drain and is electrically connected to the source/drain , and the pattern of the transparent conductive layer is complementary to the pattern of the channel layer; forming a dielectric layer on the substrate to cover the transparent conductive layer and the channel layer; and A gate is formed on the dielectric layer by using a third mask. 2. The manufacturing method of the pixel structure as claimed in claim 1, wherein the step of forming the transparent conductive layer and the channel layer comprises: forming a transparent conductive material layer on the substrate to cover the source/drain; using the second mask to form a first-type patterned photoresist layer on the transparent conductive material layer; using the first-type patterned photoresist layer as a mask to remove part of the transparent conductive material layer to form the transparent conductive layer; removing the first-type patterned photoresist layer; forming a channel material layer on the substrate; Using the second mask to form a second-type patterned photoresist layer on the channel material layer, wherein the second-type patterned photoresist layer has the same type as the first-type patterned photoresist layer different; removing part of the channel material layer by using the second-type patterned photoresist layer as a mask to form the channel layer; and The second type patterned photoresist layer is removed. 3. The manufacturing method of the pixel structure as claimed in claim 2, wherein the type of the first type patterned photoresist layer is a positive type photoresist, and the type of the second type patterned photoresist layer It is a negative photoresist. 4. The manufacturing method of the pixel structure as claimed in claim 2, wherein the type of the first type patterned photoresist layer is a negative type photoresist, and the type of the second type patterned photoresist layer For positive photoresist. 5. The manufacturing method of the pixel structure as claimed in claim 1, wherein the step of forming the transparent conductive layer and the channel layer comprises: forming a channel material layer on the substrate to cover the source/drain; forming a second-type patterned photoresist layer on the channel material layer by using the second mask; using the second-type patterned photoresist layer as a mask to remove part of the channel material layer to form the channel layer; removing the second-type patterned photoresist layer; forming a transparent conductive material layer on the substrate; Using the second mask to form a first-type patterned photoresist layer on the transparent conductive material layer, wherein the first-type patterned photoresist layer and the second-type patterned photoresist layer are different; using the first-type patterned photoresist layer as a mask to remove part of the transparent conductive material layer to form the transparent conductive layer; and The first type patterned photoresist layer is removed. 6. The manufacturing method of the pixel structure as claimed in claim 5, wherein the type of the first type patterned photoresist layer is positive type photoresist, and the type of the second type patterned photoresist layer It is a negative photoresist. 7. The manufacturing method of the pixel structure as claimed in claim 5, wherein the first-type patterned photoresist layer is a negative-type photoresist, and the second-type patterned photoresist layer is a positive-type photoresist . 8 . The method for manufacturing the pixel structure as claimed in claim 1 , further comprising forming an ohmic contact layer on the source/drain by using the first mask after the step of forming the source/drain. 9. The manufacturing method of the pixel structure according to claim 1, wherein after forming the gate, further comprising: forming a patterned photoresist layer on the dielectric layer and the gate using the first mask; using the patterned photoresist layer as a mask to remove part of the dielectric layer to form a patterned dielectric layer, wherein the patterned dielectric layer exposes part of the transparent conductive layer; and The patterned photoresist layer is removed. 10. The manufacturing method of the pixel structure according to claim 1, wherein after forming the gate, further comprising: forming a photoresist layer on the dielectric layer and the gate, wherein the gate partially overlaps the source/drain; patterning the photoresist layer by using the source/drain and the gate as a mask to form a patterned photoresist layer; using the patterned photoresist layer as a mask to remove part of the dielectric layer to form a patterned dielectric layer, wherein the patterned dielectric layer exposes part of the transparent conductive layer; and The patterned photoresist layer is removed.

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