US20010004535A1 - Method of manufacturing a thin film transistor array substrate - Google Patents
Method of manufacturing a thin film transistor array substrate Download PDFInfo
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- US20010004535A1 US20010004535A1 US09/734,010 US73401000A US2001004535A1 US 20010004535 A1 US20010004535 A1 US 20010004535A1 US 73401000 A US73401000 A US 73401000A US 2001004535 A1 US2001004535 A1 US 2001004535A1
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- 229910052751 metal Inorganic materials 0.000 description 11
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
- H01L27/1214—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
- H01L27/1259—Multistep manufacturing methods
- H01L27/1288—Multistep manufacturing methods employing particular masking sequences or specially adapted masks, e.g. half-tone mask
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
- H01L27/1214—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
- H01L29/417—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions carrying the current to be rectified, amplified or switched
- H01L29/41725—Source or drain electrodes for field effect devices
- H01L29/41733—Source or drain electrodes for field effect devices for thin film transistors with insulated gate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66742—Thin film unipolar transistors
- H01L29/6675—Amorphous silicon or polysilicon transistors
- H01L29/66765—Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
Definitions
- the present invention relates to thin film transistors and to liquid crystal display (LCD) devices.
- a LCD includes upper and lower substrates and an interposed liquid crystal layer.
- the upper substrate includes a color filter and a common electrode, while the lower substrate includes an array of switching elements and a pixel electrode.
- the liquid crystal layer is comprised of optically anisotropic liquid crystal molecules that arrange according to the state of the switching element.
- the lower substrate is often referred to as an array substrate. That substrate is manufactured using various processes such as deposition, photolithography, and etching. Manufacturing the lower substrate involves repeating those processes several times. Of the various processes, the principles of the present invention most directly relate to photolithography. Therefore, photolithography will be explained in more detail.
- FIG. 1 is a photolithography flow chart
- FIGS. 2A to 2 D are cross-sectional views illustrating a typical photolithography process.
- photolithography includes deposition, (light) exposure, and development.
- a thin film 11 is deposited on a glass substrate 10 .
- the glass substrate 10 is pre-baked to remove humidity on the substrate's surface. This enhances adhesion between the glass substrate 10 and a subsequently deposited photoresist 13 .
- the photoresist 13 is uniformly coated on the thin film 11 using spin-coating.
- a soft-bake process that evaporates solvents remaining in the photoresist 13 is performed. This hardens the photoresist 13 .
- the result is as illustrated in FIG. 2 a.
- ST 200 of FIG. 1 is carried out by placing the glass substrate 10 in a light exposure device and aligning the glass substrate with a photomask. This is shown in FIG. 2B, which shows a mask 15 .
- the glass substrate 10 then undergoes light exposure for a predetermined period of time.
- the light exposure uses ultra-violet (UV) radiation. Due to the light exposure and the mask 15 , the portion of the photoresist 13 that is not protected by the mask 15 is polymerized.
- UV ultra-violet
- ST 300 of FIG. 1 is performed as illustrated by FIG. 2C.
- either the exposed portion or the non-exposed portion of the photoresist 13 is selectively removed by a developer.
- the result is a photoresist pattern 13 .
- the glass substrate 10 is hard-baked by performing a heat-treatment at a predetermined temperature.
- ST 400 (etch) of FIG. 1 is performed as shown in FIG. 2D.
- the thin film 11 is selectively removed with the photoresist 13 acting as a mask.
- the result is a thin film pattern 11 a .
- a portion of the thin film 11 that is not covered with the photoresist pattern 13 is removed.
- ST 500 strip of FIG. 1 is performed, also as illustrated in FIG. 2D.
- the photoresist 13 on the thin film pattern 11 a is removed using a chemical stripper.
- a cleaning process is carried out, beneficially one that uses distilled water. Since the stripper tends to stick to and solidify on the surface of the substrate 10 , the substrate is first immersed in an isopropyl alcohol solution ((CH 3 ) 2 CHOH) to prevent stripper solidification. Then, the substrate 10 is cleaned using distilled water.
- FIG. 3 is a plan view illustrating an array substrate of a conventional LCD device.
- gate lines 19 are arranged in a transverse direction, and data lines 21 are arranged in a longitudinal direction.
- Pixel electrodes P are formed at a region defined by the gate and data lines 19 and 21 .
- Thin film transistors (TFTs) are formed at a crossing portion of the gate and data lines 19 and 21 .
- a storage capacitor C is formed adjacent the gate line 19 .
- a portion of the gate line 19 is used as a first electrode of the storage capacitor C, and a portion of the pixel electrode P is used a second electrode.
- a separate capacitor electrode can be formed and used instead of the portion of the gate line 19 .
- Each TFT includes a gate electrode 23 , an active layer 29 , a source electrode 25 , and a drain electrode 27 that is spaced apart from the source electrode.
- the end portion of the active layer 29 is overlapped by the source and drain electrodes 25 and 27 .
- each of the foregoing components is formed by photolithography. As the ends of the active layer 29 is overlapped by the source and drain electrodes 25 and 27 , the surface of the active layer 29 must be completely clean to prevent problems. Therefore, as described above, the array substrate is immersed in the isopropyl alcohol solution after removing the photoresist using the stripper solution.
- the isopropyl alcohol solution adversely affects an insulating layer that is beneficially located under the active layer 29 .
- the isopropyl alcohol solution is relatively costly. Therefore, an improved method of manufacturing a thin film transistor array substrate would be beneficial.
- the present invention is directed to a method of manufacturing a thin film transistor array substrate that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
- preferred embodiments of the present invention provide a method of manufacturing a thin film transistor array substrate that includes an effective method of cleaning an active layer of a thin film transistor.
- Another object of the present invention is to provide a method of manufacturing a thin film transistor array substrate that includes a low cost process of cleaning an active layer of a thin film transistor.
- the principles of the present invention provide a method of manufacturing a thin film transistor array substrate that includes forming a gate electrode on a substrate, and then sequentially forming a first insulating layer, a pure semiconductor layer and a doped semiconductor layer that cover the gate electrode.
- a photoresist layer is then coated on the doped semiconductor layer.
- the photoresist layer is then exposed and developed to form a photoresist pattern.
- the pure semiconductor layer and the doped semiconductor layer are then etched to form an active layer and an ohmic contact layer by using the photoresist pattern as a mask.
- the photoresist pattern is then removed using a stripper.
- the array substrate is then immersed into a thin alkali-based solution.
- the array substrate is then cleaned using distilled water. Spaced apart source and drain electrodes are then formed on the ohmic contact layer.
- the method further includes forming a second insulating layer over the array substrate, and then forming a pixel electrode on the second insulating layer such that the pixel electrode contacts the drain electrode.
- the alkali-based solution is diluted tetramethylamonium hydroxide (TMAH; (CH 3 ) 4 NOH).
- TMAH tetramethylamonium hydroxide
- the first and second insulating layers are beneficially comprised of inorganic material such as SiNx and SiOx, or of an organic material such as BCB (benzocyclobutene) or an acrylic-based resin.
- the pixel electrode is beneficially comprised of ITO (indium tin oxide) and/or of IZO (indium zinc oxide).
- the gate electrode is beneficially comprised of Al, an Al alloy, Mo, Ta, W and/or of Sb.
- the source and drain electrodes are beneficially comprised of Cr and/or of a chrome alloy.
- the cleaning of the active layer of a TFT can be improved.
- an alkali-based solution is relatively low cost when compared to an isopropyl alcohol solution, the cost of cleaning the active layer of a thin film transistor can be reduced.
- FIG. 1 is a flow chart illustrating a photolithography process
- FIGS. 2A to 2 D are cross-sectional views illustrating the process of FIG. 1;
- FIG. 3 is a plan view illustrating the structure of an array substrate of a conventional LCD device.
- FIGS. 4A to 4 E are cross-sectional views taken along line IV-IV of FIG. 3 and help illustrate a process of manufacturing a thin film transistor array substrate according to the principles of the present invention.
- FIGS. 4A to 4 E are cross-sectional views taken along line IV-IV of FIG. 3. Those views help illustrate a process of manufacturing a thin film transistor (TFT) array substrate according to the principles of the present invention.
- a first metal layer is deposited on a glass substrate 111 .
- the first metal layer is beneficially made of a metal such as Al, an Al alloy, Mo, Ta, W, and/or Sb.
- a photoresist layer is then coated on the first metal layer and patterned to form a first mask.
- the photoresist pattern is then heat-treated (forming a hemispherical-shaped cross-section). With the photoresist pattern acting as a mask, the first metal layer is etched to form a gate line (see 19 of FIG. 3) and a taper-shaped gate electrode 113 .
- a dry-etching technique to etch the first metal layer is preferable since the etching ratio is proportional to the flow rate of the etching gas, which is easy to control.
- a first insulating layer 115 is formed over the substrate 111 such that the first insulating layer covers the gate electrode 113 .
- the first insulating layer 115 is beneficially comprised of an inorganic material such as SiNx and SiOx, or of an organic material such as BCB (benzocyclobutene) and an acrylic-based resin.
- a pure amorphous silicon layer 116 and a doped amorphous silicon layer 118 are sequentially deposited over the substrate.
- a photoresist layer 120 is then coated over the doped semiconductor layer 118 .
- the photoresist 120 is then light exposed using a second mask.
- the photoresist 120 is then developed to form a photoresist pattern 120 a (reference FIG. 4B).
- the exposed portions of the doped semiconductor layer 118 and the pure amorphous silicon layer 116 are simultaneously etched to form an active layer 117 and an ohmic contact layer 119 .
- the remaining photoresist pattern 120 a is then removed using an organic stripper.
- the array substrate is immersed in a thin alkali-based solution, for example, diluted tetramethylamonium hydroxide (TMAH; (CH 3 ) 4 NOH).
- TMAH diluted tetramethylamonium hydroxide
- the thin alkali-based solution serves to improve the cleaning of the first insulating layer 115 under the active layer 117 .
- a thin alkali-based solution is relatively low cost. After immersion in the thin alkali-based solution the substrate is cleaned using distilled water.
- a second metal layer is deposited and patterned using a third mask into a data line (see element 21 of FIG. 3) and source and drain electrodes 121 and 123 .
- the second metal layer is beneficially made of Cr or a chrome alloy. When etching the second metal layer either a dry etching technique or a wet etching technique can be used.
- a second insulating layer is formed over the substrate 111 .
- the second insulating layer is made of either an inorganic material such as SiNx and SiOx or an organic material such as BCB (benzocyclobutene) and acrylic-based resin.
- the second insulating layer forms a passivation film 125 .
- the passivation film 125 is patterned using a fourth mask to form a contact hole 127 to the drain electrode 123 .
- a transparent conductive metal layer is deposited on the passivation film 125 .
- the conductive metal layer is then patterned into a pixel electrode 129 using a fifth mask.
- the pixel electrode 129 contacts the drain electrode 123 through the contact hole 127 .
- the pixel electrode 129 is beneficially made of ITO (indium tin oxide) or IZO (indium zinc oxide).
- the active layer is cleaned using an alkali-based solution. Cleaning is effective and lower in cost than methods that use an isopropyl alcohol solution.
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Abstract
Description
- This application claims the benefit of Korean Patent Application No. 1999-59601, filed on Dec. 21, 1999, which is hereby incorporated by reference for all purposes as if fully set forth herein.
- 1. Field of the Invention
- The present invention relates to thin film transistors and to liquid crystal display (LCD) devices.
- 2. Discussion of the Related Art
- In general, a LCD includes upper and lower substrates and an interposed liquid crystal layer. The upper substrate includes a color filter and a common electrode, while the lower substrate includes an array of switching elements and a pixel electrode. The liquid crystal layer is comprised of optically anisotropic liquid crystal molecules that arrange according to the state of the switching element.
- The lower substrate is often referred to as an array substrate. That substrate is manufactured using various processes such as deposition, photolithography, and etching. Manufacturing the lower substrate involves repeating those processes several times. Of the various processes, the principles of the present invention most directly relate to photolithography. Therefore, photolithography will be explained in more detail.
- FIG. 1 is a photolithography flow chart, and FIGS. 2A to2D are cross-sectional views illustrating a typical photolithography process. In general, photolithography includes deposition, (light) exposure, and development.
- First, as shown in FIG. 2A, a
thin film 11 is deposited on aglass substrate 10. Referring now to ST100 of FIG. 1, after the deposition of thethin film 11 theglass substrate 10 is pre-baked to remove humidity on the substrate's surface. This enhances adhesion between theglass substrate 10 and a subsequently depositedphotoresist 13. Thereafter, thephotoresist 13 is uniformly coated on thethin film 11 using spin-coating. Then, a soft-bake process that evaporates solvents remaining in thephotoresist 13 is performed. This hardens thephotoresist 13. The result is as illustrated in FIG. 2a. - ST200 of FIG. 1 is carried out by placing the
glass substrate 10 in a light exposure device and aligning the glass substrate with a photomask. This is shown in FIG. 2B, which shows amask 15. Theglass substrate 10 then undergoes light exposure for a predetermined period of time. Beneficially, the light exposure uses ultra-violet (UV) radiation. Due to the light exposure and themask 15, the portion of thephotoresist 13 that is not protected by themask 15 is polymerized. - After polymerization, ST300 of FIG. 1 is performed as illustrated by FIG. 2C. Depending on the particular process being used, either the exposed portion or the non-exposed portion of the
photoresist 13 is selectively removed by a developer. The result is aphotoresist pattern 13. To enhance the adhesion of thephotoresist pattern 13 to thethin film 11 theglass substrate 10 is hard-baked by performing a heat-treatment at a predetermined temperature. - After the hard-bake, ST400 (etch) of FIG. 1 is performed as shown in FIG. 2D. Using either a dry or a wet etch process, the
thin film 11 is selectively removed with the photoresist 13 acting as a mask. The result is athin film pattern 11 a. In other words, a portion of thethin film 11 that is not covered with thephotoresist pattern 13 is removed. - After the etch, ST500 (strip) of FIG. 1 is performed, also as illustrated in FIG. 2D. The
photoresist 13 on thethin film pattern 11 a is removed using a chemical stripper. After stripping, a cleaning process is carried out, beneficially one that uses distilled water. Since the stripper tends to stick to and solidify on the surface of thesubstrate 10, the substrate is first immersed in an isopropyl alcohol solution ((CH3)2CHOH) to prevent stripper solidification. Then, thesubstrate 10 is cleaned using distilled water. - The structure of a conventional array substrate that is manufactured using the foregoing photolithography process is explained below. FIG. 3 is a plan view illustrating an array substrate of a conventional LCD device. As shown in FIG. 3,
gate lines 19 are arranged in a transverse direction, anddata lines 21 are arranged in a longitudinal direction. Pixel electrodes P are formed at a region defined by the gate anddata lines data lines gate line 19. A portion of thegate line 19 is used as a first electrode of the storage capacitor C, and a portion of the pixel electrode P is used a second electrode. Alternatively, a separate capacitor electrode can be formed and used instead of the portion of thegate line 19. - Each TFT includes a
gate electrode 23, anactive layer 29, asource electrode 25, and adrain electrode 27 that is spaced apart from the source electrode. The end portion of theactive layer 29 is overlapped by the source anddrain electrodes - Each of the foregoing components is formed by photolithography. As the ends of the
active layer 29 is overlapped by the source anddrain electrodes active layer 29 must be completely clean to prevent problems. Therefore, as described above, the array substrate is immersed in the isopropyl alcohol solution after removing the photoresist using the stripper solution. - However, the isopropyl alcohol solution adversely affects an insulating layer that is beneficially located under the
active layer 29. In addition, the isopropyl alcohol solution is relatively costly. Therefore, an improved method of manufacturing a thin film transistor array substrate would be beneficial. - Accordingly, the present invention is directed to a method of manufacturing a thin film transistor array substrate that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
- To overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a thin film transistor array substrate that includes an effective method of cleaning an active layer of a thin film transistor.
- Another object of the present invention is to provide a method of manufacturing a thin film transistor array substrate that includes a low cost process of cleaning an active layer of a thin film transistor.
- Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from that description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
- To achieve the above objects, the principles of the present invention provide a method of manufacturing a thin film transistor array substrate that includes forming a gate electrode on a substrate, and then sequentially forming a first insulating layer, a pure semiconductor layer and a doped semiconductor layer that cover the gate electrode. A photoresist layer is then coated on the doped semiconductor layer. The photoresist layer is then exposed and developed to form a photoresist pattern. The pure semiconductor layer and the doped semiconductor layer are then etched to form an active layer and an ohmic contact layer by using the photoresist pattern as a mask. The photoresist pattern is then removed using a stripper. The array substrate is then immersed into a thin alkali-based solution. The array substrate is then cleaned using distilled water. Spaced apart source and drain electrodes are then formed on the ohmic contact layer.
- The method further includes forming a second insulating layer over the array substrate, and then forming a pixel electrode on the second insulating layer such that the pixel electrode contacts the drain electrode.
- Beneficially, the alkali-based solution is diluted tetramethylamonium hydroxide (TMAH; (CH3)4NOH). The first and second insulating layers are beneficially comprised of inorganic material such as SiNx and SiOx, or of an organic material such as BCB (benzocyclobutene) or an acrylic-based resin. The pixel electrode is beneficially comprised of ITO (indium tin oxide) and/or of IZO (indium zinc oxide). The gate electrode is beneficially comprised of Al, an Al alloy, Mo, Ta, W and/or of Sb. The source and drain electrodes are beneficially comprised of Cr and/or of a chrome alloy.
- By using a method of manufacturing a TFT array substrate according to the principles of the present invention, the cleaning of the active layer of a TFT can be improved. In addition, since an alkali-based solution is relatively low cost when compared to an isopropyl alcohol solution, the cost of cleaning the active layer of a thin film transistor can be reduced.
- It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
- The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
- In the drawings:
- FIG. 1 is a flow chart illustrating a photolithography process;
- FIGS. 2A to2D are cross-sectional views illustrating the process of FIG. 1;
- FIG. 3 is a plan view illustrating the structure of an array substrate of a conventional LCD device; and
- FIGS. 4A to4E are cross-sectional views taken along line IV-IV of FIG. 3 and help illustrate a process of manufacturing a thin film transistor array substrate according to the principles of the present invention.
- Reference will now be made in detail to an illustrated embodiment of the present invention, the example of which is shown in the accompanying drawings.
- FIGS. 4A to4E are cross-sectional views taken along line IV-IV of FIG. 3. Those views help illustrate a process of manufacturing a thin film transistor (TFT) array substrate according to the principles of the present invention. First, as shown in FIG. 4A, a first metal layer is deposited on a
glass substrate 111. The first metal layer is beneficially made of a metal such as Al, an Al alloy, Mo, Ta, W, and/or Sb. A photoresist layer is then coated on the first metal layer and patterned to form a first mask. - The photoresist pattern is then heat-treated (forming a hemispherical-shaped cross-section). With the photoresist pattern acting as a mask, the first metal layer is etched to form a gate line (see19 of FIG. 3) and a taper-shaped
gate electrode 113. Using a dry-etching technique to etch the first metal layer is preferable since the etching ratio is proportional to the flow rate of the etching gas, which is easy to control. - Next, a first insulating
layer 115 is formed over thesubstrate 111 such that the first insulating layer covers thegate electrode 113. The first insulatinglayer 115 is beneficially comprised of an inorganic material such as SiNx and SiOx, or of an organic material such as BCB (benzocyclobutene) and an acrylic-based resin. - Then, a pure
amorphous silicon layer 116 and a dopedamorphous silicon layer 118 are sequentially deposited over the substrate. Aphotoresist layer 120 is then coated over the dopedsemiconductor layer 118. Thephotoresist 120 is then light exposed using a second mask. Thephotoresist 120 is then developed to form aphotoresist pattern 120 a (reference FIG. 4B). - As shown in FIG. 4B, using the
photoresist pattern 120 a as a mask, the exposed portions of the dopedsemiconductor layer 118 and the pureamorphous silicon layer 116 are simultaneously etched to form anactive layer 117 and anohmic contact layer 119. The remainingphotoresist pattern 120 a is then removed using an organic stripper. - After that, the array substrate is immersed in a thin alkali-based solution, for example, diluted tetramethylamonium hydroxide (TMAH; (CH3)4NOH). This prevents the stripper from solidifying before it can be cleaned using distilled water. The thin alkali-based solution serves to improve the cleaning of the first insulating
layer 115 under theactive layer 117. Furthermore, a thin alkali-based solution is relatively low cost. After immersion in the thin alkali-based solution the substrate is cleaned using distilled water. - After the cleaning of the
active layer 117 and the first insulatinglayer 115, as shown in FIG. 4C, a second metal layer is deposited and patterned using a third mask into a data line (seeelement 21 of FIG. 3) and source and drainelectrodes - Subsequently, as shown in FIG. 4d, a second insulating layer is formed over the
substrate 111. The second insulating layer is made of either an inorganic material such as SiNx and SiOx or an organic material such as BCB (benzocyclobutene) and acrylic-based resin. The second insulating layer forms apassivation film 125. Then, thepassivation film 125 is patterned using a fourth mask to form acontact hole 127 to thedrain electrode 123. - Finally, as shown in FIG. 4e, a transparent conductive metal layer is deposited on the
passivation film 125. The conductive metal layer is then patterned into apixel electrode 129 using a fifth mask. Thepixel electrode 129 contacts thedrain electrode 123 through thecontact hole 127. Thepixel electrode 129 is beneficially made of ITO (indium tin oxide) or IZO (indium zinc oxide). - As described above, using a method of manufacturing a TFT array substrate according to the principles of the present invention the active layer is cleaned using an alkali-based solution. Cleaning is effective and lower in cost than methods that use an isopropyl alcohol solution.
- It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims (19)
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KR1019990059601A KR20010065038A (en) | 1999-12-21 | 1999-12-21 | method for fabricating thin film transistor and array substrate for liquid crystal display device |
KR1999-59601 | 1999-12-21 |
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US20010004535A1 true US20010004535A1 (en) | 2001-06-21 |
US6406969B2 US6406969B2 (en) | 2002-06-18 |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US8470622B1 (en) * | 2012-03-06 | 2013-06-25 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | Method for manufacturing array substrate of transmissive liquid crystal display |
US20150072275A1 (en) * | 2013-09-10 | 2015-03-12 | Chi Mei Corporation | Positive photosensitive resin composition and method for forming pattern by using the same |
Families Citing this family (7)
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US6486010B1 (en) * | 2002-03-14 | 2002-11-26 | Chi Mei Optoelectronics Corp. | Method for manufacturing thin film transistor panel |
KR100499376B1 (en) * | 2003-10-10 | 2005-07-04 | 엘지.필립스 엘시디 주식회사 | Thin film transistor array substrate and manufacturing method of the same |
US8309502B2 (en) * | 2009-03-27 | 2012-11-13 | Eastman Chemical Company | Compositions and methods for removing organic substances |
US8444768B2 (en) * | 2009-03-27 | 2013-05-21 | Eastman Chemical Company | Compositions and methods for removing organic substances |
US8614053B2 (en) | 2009-03-27 | 2013-12-24 | Eastman Chemical Company | Processess and compositions for removing substances from substrates |
US9029268B2 (en) | 2012-11-21 | 2015-05-12 | Dynaloy, Llc | Process for etching metals |
CN105551955A (en) * | 2016-02-23 | 2016-05-04 | 华南理工大学 | Preparation method for oxide thin film and thin film transistor |
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KR970011972A (en) * | 1995-08-11 | 1997-03-29 | 쯔지 하루오 | Transmission type liquid crystal display device and manufacturing method thereof |
US6080606A (en) * | 1996-03-26 | 2000-06-27 | The Trustees Of Princeton University | Electrophotographic patterning of thin film circuits |
DE19712233C2 (en) * | 1996-03-26 | 2003-12-11 | Lg Philips Lcd Co | Liquid crystal display and manufacturing method therefor |
KR19980027415A (en) * | 1996-10-16 | 1998-07-15 | 구자홍 | Cleaning method using developer |
KR100213292B1 (en) * | 1996-11-29 | 1999-08-02 | 전주범 | Method and composition for removing photosensitive resin on the wafer |
JP3276573B2 (en) * | 1996-12-26 | 2002-04-22 | 三菱電機株式会社 | Liquid crystal display device and method of manufacturing thin film transistor used therein |
JP3844846B2 (en) * | 1997-06-12 | 2006-11-15 | 東芝電子エンジニアリング株式会社 | Liquid crystal display device and manufacturing method thereof |
JPH11233782A (en) * | 1998-02-16 | 1999-08-27 | Nec Kagoshima Ltd | Manufacture of tft array |
KR100276442B1 (en) * | 1998-02-20 | 2000-12-15 | 구본준 | Liquid crystal display device and its fabrication method |
US6117791A (en) * | 1998-06-22 | 2000-09-12 | Micron Technology, Inc. | Etchant with selectivity for doped silicon dioxide over undoped silicon dioxide and silicon nitride, processes which employ the etchant, and structures formed thereby |
US6309926B1 (en) * | 1998-12-04 | 2001-10-30 | Advanced Micro Devices | Thin resist with nitride hard mask for gate etch application |
-
1999
- 1999-12-21 KR KR1019990059601A patent/KR20010065038A/en not_active Application Discontinuation
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Cited By (3)
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US8470622B1 (en) * | 2012-03-06 | 2013-06-25 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | Method for manufacturing array substrate of transmissive liquid crystal display |
US20150072275A1 (en) * | 2013-09-10 | 2015-03-12 | Chi Mei Corporation | Positive photosensitive resin composition and method for forming pattern by using the same |
US9395627B2 (en) * | 2013-09-10 | 2016-07-19 | Chi Mei Corporation | Positive photosensitive resin composition and method for forming pattern by using the same |
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US6406969B2 (en) | 2002-06-18 |
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