US20010046000A1 - A method for manufacturing an lck in which a photoresist layer is at least 1.2 times thicker than the passivation layer - Google Patents
A method for manufacturing an lck in which a photoresist layer is at least 1.2 times thicker than the passivation layer Download PDFInfo
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- US20010046000A1 US20010046000A1 US09/213,705 US21370598A US2001046000A1 US 20010046000 A1 US20010046000 A1 US 20010046000A1 US 21370598 A US21370598 A US 21370598A US 2001046000 A1 US2001046000 A1 US 2001046000A1
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
- G02F1/1362—Active matrix addressed cells
- G02F1/136227—Through-hole connection of the pixel electrode to the active element through an insulation layer
Definitions
- the present invention relates to a method of patterning a pixel electrode of a liquid crystal display (LCD) device including a switching element for driving and controlling a liquid crystal. More specifically, the present invention relates to a patterning method for manufacturing a liquid crystal display having a TFT (thin film transistors) functioning as a switching element in which a passivation layer covers the TFT and a pixel electrode is connected to an output electrode of the TFT on the passivation layer, and also relates to a structure of a liquid crystal display device manufactured by this method.
- TFT thin film transistors
- an LCD has a structure as shown in FIG. 1 which illustrates a plane view of an enlarged LCD panel.
- a gate line 17 is arranged to extend in a horizontal direction and a data line 15 is arranged to extend in a vertical direction which crosses the gate line 17 perpendicularly.
- a TFT including a gate electrode 17 a , a source electrode 15 a , a drain electrode 15 b and a semiconductor layer 22 is formed.
- a passivation layer (not shown) is formed thereon.
- a pixel electrode 4 connected to the drain electrode 15 b is formed on the passivation layer 22 .
- FIG. 2 shows the typically distorted shape of the pixel electrode 4 after being patterned by the conventional method.
- the dotted line 55 in FIG. 2 is the boundary of the originally designed shape of the pixel electrode 4 .
- the pixel electrode 4 has a distorted boundary portion having a width W2 and tearing-off portions 20 in the pixel electrode.
- W 1 is a width of the data line 15 .
- FIGS. 3 a - 3 j are cross-sectional views cut along the a-a line of the FIG. 1, a conventional method for manufacturing the LCD will be explained in order to illustrate the reason for the pixel electrode having an undesired pattern shown in FIG. 2.
- a metal selected from the group of aluminum (Al), aluminum alloy, chromium (Cr) or molybdenum (Mo) is deposited to form a first metal layer 50 .
- a photo resist 51 is coated on the first metal layer 50 as shown in FIG. 3A.
- the photo resist 51 is patterned to have a predetermined shape.
- the first metal layer 50 is patterned according to the shape of the photo resist 51 to form a gate line (not shown) and to form a gate electrode 17 a which is derived from the gate line. Then the remaining photo resist on the gate line and the gate electrode 17 a is removed as shown in FIG. 3B.
- the gate electrode 17 a can be anodized to eliminate hillocks thereon.
- the cross-sectional shape of the gate electrode 17 a preferably has a tapered shape.
- a gate insulating layer 23 including an inorganic insulating material such as SiN x or SiO x , an amorphous silicon (or a-Si) 52 and an n + type impurity doped a-Si (or N + type a-Si) 53 are sequentially deposited.
- a photo resist 51 is coated thereon as shown in FIG. 3C.
- the photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51 , the a-Si material 52 and the n + type a-Si material 53 are simultaneously etched to form a semiconductor layer 22 and an ohmic contact layer 25 . The remaining photo resist 51 on the ohmic contact layer 25 is removed as shown in FIG. 3D.
- a second metal layer 54 including chromium or aluminum is deposited and a photo resist 51 is coated on the second metal layer 54 as shown in FIG. 3E.
- the photo resist 51 is patterned to have a predetermined shape.
- the second metal layer 54 is patterned via a wet etching method to form a data line 15 .
- a source electrode 15 a derived from the data line 15 and a drain electrode 15 b which faces the source electrode 15 a are formed on the ohmic contact layer 25 whereas the source electrode 15 a and the drain electrode 15 b are separated via a distance.
- the n + type a-Si material 53 between the source electrode 15 a and the drain electrode 15 b is removed via a dry etching method using the source electrode 15 a and the drain electrode 15 b as a mask.
- the remaining photo resist on the source electrode 15 a and the drain electrode 15 b is removed as shown in FIG. 3F.
- a passivation layer 26 including an organic material such as BCB (or benzocyclobutene) is coated thereon via a spin coating method.
- a photo resist 51 is coated so as to have a thickness that is less than a thickness of the passivation layer 26 as shown in FIG. 3G.
- the photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51 , the passivation layer 26 is patterned via a dry etching method to form a contact hole 30 which exposes some portions of the drain electrode 15 b . The remaining photo resist on the passivation layer 26 is removed as shown in FIG. 3H.
- an ITO (or Indium Tin Oxide) 55 is deposited so as to have a thickness of about 500 ⁇ .
- a photo resist 51 is coated as shown in FIG. 3I.
- the photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51 , the ITO layer 55 is patterned via a wet etching method to form a pixel electrode 4 as shown in FIG. 3J.
- the passivation layer 26 has a lower dielectric constant (lower than 3.0) than the inorganic material and forms an organic insulating layer(BCB) which can even a surface property thereof, the pixel electrode 4 disposed on the passivation layer can be overlapped with the data line 15 so that the aperture ratio can be maximized.
- the surface of the patterned passivation layer 26 can be rough and uneven.
- the patterned pixel electrode 4 has distorted edge portions and tearing-off portions as shown in FIG. 2.
- the substrate which has the passivation layer and patterned photo resist is inserted into an etching chamber filled with an etching gas such as O 2 /SF 6 or O 2 /CF 4 .
- an etching gas such as O 2 /SF 6 or O 2 /CF 4 .
- the portions of the passivation layer exposed through the patterned photo resist are removed by changing a volatile material SiF4 according to the chemical reaction of the Si functional group of the passivation layer and the F radical of the SF 6 or CF 4 .
- the photo resist is removed by ashing with O 2 gas.
- the thickness of the photo resist is the same as that of the passivation layer. So, when the patterning of the passivation layer is finished, the photo resist is almost completely removed.
- the ITO layer is deposited on the uneven passivation layer, the ITO is not deposited at the convex portions 20 which have the extruded passivation layer as shown in FIG. 5.
- a photo resist is then deposited and patterned on the ITO layer 60 which is not uniformly deposited.
- the pixel electrode does not have the originally designed shape. For example, the edges of the pixel electrode 4 do not reach the portion A and therefore, the edge of the pixel electrode has a reduced width W.
- the aperture ratio of the pixel electrode cannot be maximized. Furthermore, since the tearing-off portion of the pixel electrode does not generate an electrical field for driving the liquid crystal, the picture quality is inferior.
- preferred embodiments of the present invention provide a method for patterning a thin layer to have an originally designed shape.
- Preferred embodiments of the present invention also provide a method for patterning a pixel electrode to have an originally designed shape.
- Another preferred embodiment of the present invention provides a method for manufacturing an LCD having a pixel electrode of which an aperture ratio is maximized.
- another preferred embodiment of the present invention provides a method for manufacturing the LCD which has a high picture quality resulting from a desired patterning of the pixel electrode.
- preferred embodiments of the present invention provide a method of patterning the passivation layer which includes the steps of coating a photo resist to have a thickness of more than about 1.2 times of a thickness of the passivation layer, patterning the photo resist to have a predetermined shape, etching the passivation layer according to the patterned photo resist, removing the remaining photo resist and treating the surface of the passivation layer so as to form an SiO 2 thin layer on the passivation layer using O 2 gas and forming a pixel electrode on the passivation layer by depositing and patterning an ITO layer.
- a thin photo resist layer still covers the passivation layer. Because the photo resist is about 1.2 times thicker than the passivation layer, all surfaces of the patterned passivation layer can be covered by the photo resist, even if the thickness of the photo resist is not uniform. Therefore, the passivation layer does not contact the etching gas so that the passivation layer is not over-etched by the etching gas.
- the remaining photo resist is removed via ashing with O 2 .
- the ashing process continuously treats some surfaces of the passivation layer so that a thin SiO 2 layer is formed on the passivation layer.
- FIG. 1 is a plane view of the conventional liquid crystal display device
- FIG. 2 is a plane view illustrating the pixel electrode having a distorted edge portion and tearing-off portions therein according to the conventional method
- FIGS. 3 a - 3 j show cross-sectional views for explaining a conventional method of manufacturing the liquid crystal display
- FIG. 4 is a cross-sectional view illustrating the uneven surface of the passivation layer after patterning according to the conventional method
- FIG. 5 is a cross-sectional view illustrating the patterned pixel electrode having an undesired patterning result according to the conventional method
- FIG. 6 is a plane view of a liquid crystal display according to a preferred embodiment of the present invention.
- FIGS. 7 a - 7 e show cross-sectional views for explaining a method for manufacturing a liquid crystal display according to a preferred embodiment of the present invention.
- FIG. 6 is a plane view of a liquid crystal display having a pixel electrode patterned according to an original design of a preferred embodiment of the present invention.
- FIGS. 7 a - 7 e are cross-sectional views showing a method for manufacturing a liquid crystal display which is cut along the a-a line of the FIG. 6.
- a gate electrode 117 a derived from a gate line 117 , a gate insulating layer 123 , a semiconductor layer 122 and an ohmic contact layer 125 , a source electrode 115 a derived from a data line 115 , and a drain electrode 115 b are formed by the same conventional method as described above.
- a passivation layer 126 including an organic material such as BCB is coated on the entire surface of the substrate 111 having the source 115 a and the drain electrode 115 b .
- a photo resist 151 is coated on the passivation layer 126 which is about 1.2 times thicker than the passivation layer 126 .
- the photo resist 151 is patterned so as to have a predetermined shape wherein a contact hole for exposing the drain electrode 115 b is formed as shown in FIG. 7A.
- the substrate 111 having the patterned photo resist 151 is inserted into an etching chamber which is filled with O 2 /SF 6 gas or O 2 /CF 4 gas. Then, the exposed portions of the passivation layer start to be removed by changing into a volatile material SiF 4 which is generated by the chemical reaction of the Si functional group of the passivation layer and F radical of the SF 6 or CF 4 gas. As a result, a contact hole 130 exposing some portions of the drain electrode 115 b is formed.
- the photo resist 151 starts to be ashed by the O 2 gas. Since the etching speed of the passivation layer 126 and the ashing speed of the photo resist are similar to each other, when the contact hole is formed, the photo resist having a thickness which is about 0.2 times that of the passivation layer remains as shown in FIG. 7 b.
- the remaining photo resist is removed by ashing with only O 2 gas.
- the ashing step is performed continuously in order to form a thin SiO 2 layer 170 on the passivation layer by ashing with the O 2 gas as shown in FIG. 7C.
- the remaining photo resist is removed by using an organic mixture solution including NMP (or N-Methyl-Pyrrolidone), alcohol and amine, then a SiO 2 thin layer 170 is formed by treating the surface of the passivation layer with O 2 gas.
- NMP or N-Methyl-Pyrrolidone
- the passivation layer is not exposed to the SF 6 or CF 4 , so the passivation layer is not over-etched by these gases and as a result, the passivation layer has a uniform surface.
- the etching gas is either SF 6 gas and CF 4 gas
- the etching gas can be changed according to the material of the passivation layer.
- an ITO (Indium Tin Oxide) 156 is deposited so as to have a thickness of about 500 ⁇ .
- a photo resist 151 is coated on the ITO layer 156 and patterned to have a predetermined shape as shown in FIG. 7D.
- the ITO layer 156 is patterned via wet etching method to form a pixel electrode 104 . Because the passivation layer has a low dielectric constant (lower than 3.0) and an even surface, the pixel electrode 104 can be overlapped with some portions of the data line and gate line.
- the photo resist for patterning the passivation layer is thicker than that of the passivation layer, even though the patterning of the passivation layer is finished, the photo resist still prevents the passivation layer from reacting with the etching gas. Therefore, the passivation layer has a uniform surface after the patterning.
- the pixel electrode formed on the passivation layer can be patterned to have an originally designed shape. Therefore, the LCD includes a pixel electrode having a maximum aperture ratio and an excellent quality of the picture.
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Abstract
Description
- 1. Field of the Invention
- The present invention relates to a method of patterning a pixel electrode of a liquid crystal display (LCD) device including a switching element for driving and controlling a liquid crystal. More specifically, the present invention relates to a patterning method for manufacturing a liquid crystal display having a TFT (thin film transistors) functioning as a switching element in which a passivation layer covers the TFT and a pixel electrode is connected to an output electrode of the TFT on the passivation layer, and also relates to a structure of a liquid crystal display device manufactured by this method.
- 2. Description of the Background Art
- Conventionally, an LCD has a structure as shown in FIG. 1 which illustrates a plane view of an enlarged LCD panel. A
gate line 17 is arranged to extend in a horizontal direction and adata line 15 is arranged to extend in a vertical direction which crosses thegate line 17 perpendicularly. At the intersection portion of thegate line 17 and thedata line 15, a TFT including agate electrode 17 a, asource electrode 15 a, adrain electrode 15 b and asemiconductor layer 22 is formed. A passivation layer (not shown) is formed thereon. Apixel electrode 4 connected to thedrain electrode 15 b is formed on thepassivation layer 22. - When patterning the
pixel electrode 4 according to the conventional method, the actual patterned shape is often different from the originally designed shape or desired shape. FIG. 2 shows the typically distorted shape of thepixel electrode 4 after being patterned by the conventional method. - The
dotted line 55 in FIG. 2 is the boundary of the originally designed shape of thepixel electrode 4. As seen in FIG. 2, thepixel electrode 4 has a distorted boundary portion having a width W2 and tearing-offportions 20 in the pixel electrode. Here, W1 is a width of thedata line 15. - Referring to FIGS. 3a-3 j which are cross-sectional views cut along the a-a line of the FIG. 1, a conventional method for manufacturing the LCD will be explained in order to illustrate the reason for the pixel electrode having an undesired pattern shown in FIG. 2.
- On a
transparent substrate 11, a metal selected from the group of aluminum (Al), aluminum alloy, chromium (Cr) or molybdenum (Mo) is deposited to form afirst metal layer 50. Aphoto resist 51 is coated on thefirst metal layer 50 as shown in FIG. 3A. - The
photo resist 51 is patterned to have a predetermined shape. Using a wet etching method, thefirst metal layer 50 is patterned according to the shape of the photo resist 51 to form a gate line (not shown) and to form agate electrode 17 a which is derived from the gate line. Then the remaining photo resist on the gate line and thegate electrode 17 a is removed as shown in FIG. 3B. Thegate electrode 17 a can be anodized to eliminate hillocks thereon. In addition, the cross-sectional shape of thegate electrode 17 a preferably has a tapered shape. - On the substrate having the
gate electrode 17 a, agate insulating layer 23 including an inorganic insulating material such as SiNx or SiOx, an amorphous silicon (or a-Si) 52 and an n+ type impurity doped a-Si (or N+ type a-Si) 53 are sequentially deposited. Aphoto resist 51 is coated thereon as shown in FIG. 3C. - The
photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51, the a-Simaterial 52 and the n+ type a-Simaterial 53 are simultaneously etched to form asemiconductor layer 22 and anohmic contact layer 25. The remaining photo resist 51 on theohmic contact layer 25 is removed as shown in FIG. 3D. - A
second metal layer 54 including chromium or aluminum is deposited and aphoto resist 51 is coated on thesecond metal layer 54 as shown in FIG. 3E. - The
photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51, thesecond metal layer 54 is patterned via a wet etching method to form adata line 15. At the same time, asource electrode 15 a derived from thedata line 15 and adrain electrode 15 b which faces thesource electrode 15 a are formed on theohmic contact layer 25 whereas thesource electrode 15 a and thedrain electrode 15 b are separated via a distance. The n+ type a-Simaterial 53 between thesource electrode 15 a and thedrain electrode 15 b is removed via a dry etching method using thesource electrode 15 a and thedrain electrode 15 b as a mask. The remaining photo resist on thesource electrode 15 a and thedrain electrode 15 b is removed as shown in FIG. 3F. - A
passivation layer 26 including an organic material such as BCB (or benzocyclobutene) is coated thereon via a spin coating method. Aphoto resist 51 is coated so as to have a thickness that is less than a thickness of thepassivation layer 26 as shown in FIG. 3G. - The
photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51, thepassivation layer 26 is patterned via a dry etching method to form acontact hole 30 which exposes some portions of thedrain electrode 15 b. The remaining photo resist on thepassivation layer 26 is removed as shown in FIG. 3H. - On the
passivation layer 26, an ITO (or Indium Tin Oxide) 55 is deposited so as to have a thickness of about 500 Å. On the ITOlayer 55, aphoto resist 51 is coated as shown in FIG. 3I. - The
photo resist 51 is patterned to have a predetermined shape. According to the patterned photo resist 51, the ITOlayer 55 is patterned via a wet etching method to form apixel electrode 4 as shown in FIG. 3J. - In the above mentioned conventional method, because the
passivation layer 26 has a lower dielectric constant (lower than 3.0) than the inorganic material and forms an organic insulating layer(BCB) which can even a surface property thereof, thepixel electrode 4 disposed on the passivation layer can be overlapped with thedata line 15 so that the aperture ratio can be maximized. - However, after the
passivation layer 26 including an organic material such as BCB is patterned by using a photo resist 51 as shown in FIGS. 3G and 3H, the surface of the patternedpassivation layer 26 can be rough and uneven. - If the
pixel electrode 4 is formed on the uneven surface of thepassivation layer 26, the patternedpixel electrode 4 has distorted edge portions and tearing-off portions as shown in FIG. 2. - The cause of the formation of the distorted pattern is explained hereafter in detail.
- When the passivation layer having an Si bond structure such as BCB is patterned, the substrate which has the passivation layer and patterned photo resist is inserted into an etching chamber filled with an etching gas such as O2/SF6 or O2/CF4. The portions of the passivation layer exposed through the patterned photo resist are removed by changing a volatile material SiF4 according to the chemical reaction of the Si functional group of the passivation layer and the F radical of the SF6 or CF4. At the same time, the photo resist is removed by ashing with O2 gas.
- As the etching speed of the passivation layer and the ashing speed of the photo resist is similar, the thickness of the photo resist is the same as that of the passivation layer. So, when the patterning of the passivation layer is finished, the photo resist is almost completely removed.
- However, it is very difficult to coat the photo resist to have a uniform thickness. Therefore, after the patterning of the passivation layer is finished, the portions where the photo resist is thicker have some remaining photo resist. Otherwise, at the portion where the photo resist is thinner, some surfaces of the passivation layer are over-etched by the etching gas as shown in FIG. 4.
- For example, when O2/CF4 is used as the etching gas, the ratio of the composed atoms at the surface of the over etched passivation layer is determined to be Si:C:O:F=2-3:58:24:10. Even if the surface is treated with O2 gas, the surface of the passivation layer is still uneven because of the F radical.
- If the ITO layer is deposited on the uneven passivation layer, the ITO is not deposited at the
convex portions 20 which have the extruded passivation layer as shown in FIG. 5. A photo resist is then deposited and patterned on theITO layer 60 which is not uniformly deposited. When theITO layer 60 is patterned according to the patterned photo resist, the pixel electrode does not have the originally designed shape. For example, the edges of thepixel electrode 4 do not reach the portion A and therefore, the edge of the pixel electrode has a reduced width W. - Therefore, the aperture ratio of the pixel electrode cannot be maximized. Furthermore, since the tearing-off portion of the pixel electrode does not generate an electrical field for driving the liquid crystal, the picture quality is inferior.
- To overcome the problems described above, preferred embodiments of the present invention provide a method for patterning a thin layer to have an originally designed shape. Preferred embodiments of the present invention also provide a method for patterning a pixel electrode to have an originally designed shape. Another preferred embodiment of the present invention provides a method for manufacturing an LCD having a pixel electrode of which an aperture ratio is maximized. In addition, another preferred embodiment of the present invention provides a method for manufacturing the LCD which has a high picture quality resulting from a desired patterning of the pixel electrode.
- In order to overcome problems with the conventional method and to achieve the advantages described in the preceding paragraph, preferred embodiments of the present invention provide a method of patterning the passivation layer which includes the steps of coating a photo resist to have a thickness of more than about 1.2 times of a thickness of the passivation layer, patterning the photo resist to have a predetermined shape, etching the passivation layer according to the patterned photo resist, removing the remaining photo resist and treating the surface of the passivation layer so as to form an SiO2 thin layer on the passivation layer using O2 gas and forming a pixel electrode on the passivation layer by depositing and patterning an ITO layer.
- According to preferred embodiments of the present invention, even after the patterning of the passivation layer is finished, a thin photo resist layer still covers the passivation layer. Because the photo resist is about 1.2 times thicker than the passivation layer, all surfaces of the patterned passivation layer can be covered by the photo resist, even if the thickness of the photo resist is not uniform. Therefore, the passivation layer does not contact the etching gas so that the passivation layer is not over-etched by the etching gas.
- After that, the remaining photo resist is removed via ashing with O2. Then preferably, the ashing process continuously treats some surfaces of the passivation layer so that a thin SiO2 layer is formed on the passivation layer.
- The present invention will be more fully understood from the detailed description given hereafter and the accompanying drawings which are provided as a way of illustration only and therefor not limited to the present invention and wherein:
- FIG. 1 is a plane view of the conventional liquid crystal display device;
- FIG. 2 is a plane view illustrating the pixel electrode having a distorted edge portion and tearing-off portions therein according to the conventional method;
- FIGS. 3a-3 j show cross-sectional views for explaining a conventional method of manufacturing the liquid crystal display;
- FIG. 4 is a cross-sectional view illustrating the uneven surface of the passivation layer after patterning according to the conventional method;
- FIG. 5 is a cross-sectional view illustrating the patterned pixel electrode having an undesired patterning result according to the conventional method;
- FIG. 6 is a plane view of a liquid crystal display according to a preferred embodiment of the present invention; and
- FIGS. 7a-7 e show cross-sectional views for explaining a method for manufacturing a liquid crystal display according to a preferred embodiment of the present invention.
- With reference to the figures, preferred embodiments of the present invention will be explained in detail. FIG. 6 is a plane view of a liquid crystal display having a pixel electrode patterned according to an original design of a preferred embodiment of the present invention. FIGS. 7a-7 e are cross-sectional views showing a method for manufacturing a liquid crystal display which is cut along the a-a line of the FIG. 6.
- On a
transparent substrate 111, agate electrode 117 a derived from a gate line 117, agate insulating layer 123, asemiconductor layer 122 and anohmic contact layer 125, asource electrode 115 a derived from adata line 115, and adrain electrode 115 b are formed by the same conventional method as described above. - A
passivation layer 126 including an organic material such as BCB is coated on the entire surface of thesubstrate 111 having thesource 115 a and thedrain electrode 115 b. A photo resist 151 is coated on thepassivation layer 126 which is about 1.2 times thicker than thepassivation layer 126. The photo resist 151 is patterned so as to have a predetermined shape wherein a contact hole for exposing thedrain electrode 115 b is formed as shown in FIG. 7A. - The
substrate 111 having the patterned photo resist 151 is inserted into an etching chamber which is filled with O2/SF6 gas or O2/CF4 gas. Then, the exposed portions of the passivation layer start to be removed by changing into a volatile material SiF4 which is generated by the chemical reaction of the Si functional group of the passivation layer and F radical of the SF6 or CF4 gas. As a result, acontact hole 130 exposing some portions of thedrain electrode 115 b is formed. - At the same time, the photo resist151 starts to be ashed by the O2 gas. Since the etching speed of the
passivation layer 126 and the ashing speed of the photo resist are similar to each other, when the contact hole is formed, the photo resist having a thickness which is about 0.2 times that of the passivation layer remains as shown in FIG. 7b. - After removing the SF6 or CF4 gas from the etching chamber, the remaining photo resist is removed by ashing with only O2 gas. After all of the photo resist material is removed, the ashing step is performed continuously in order to form a thin SiO2 layer 170 on the passivation layer by ashing with the O2 gas as shown in FIG. 7C.
- In another method, the remaining photo resist is removed by using an organic mixture solution including NMP (or N-Methyl-Pyrrolidone), alcohol and amine, then a SiO2
thin layer 170 is formed by treating the surface of the passivation layer with O2 gas. - As a result of preferred embodiments of the present invention, the passivation layer is not exposed to the SF6 or CF4, so the passivation layer is not over-etched by these gases and as a result, the passivation layer has a uniform surface. For example, when O2/CF4 gas is used for an etching gas, the ratio of the composed atoms at the surface of the over-etched passivation layer is determined to be Si:C:O:F=24.3:21.6:52.3:0. According to the atom ratio, the surface of the passivation layer does not react with the F radical of the CF4.
- In this preferred embodiment, even though the etching gas is either SF6 gas and CF4 gas, the etching gas can be changed according to the material of the passivation layer.
- On the entire surface of the
substrate 111 having thecontact hole 130, an ITO (Indium Tin Oxide) 156 is deposited so as to have a thickness of about 500 Å. A photo resist 151 is coated on theITO layer 156 and patterned to have a predetermined shape as shown in FIG. 7D. - According to the patterned photo resist151, the
ITO layer 156 is patterned via wet etching method to form apixel electrode 104. Because the passivation layer has a low dielectric constant (lower than 3.0) and an even surface, thepixel electrode 104 can be overlapped with some portions of the data line and gate line. - As described above, according to preferred embodiments of the present invention, because the photo resist for patterning the passivation layer is thicker than that of the passivation layer, even though the patterning of the passivation layer is finished, the photo resist still prevents the passivation layer from reacting with the etching gas. Therefore, the passivation layer has a uniform surface after the patterning.
- So, the pixel electrode formed on the passivation layer can be patterned to have an originally designed shape. Therefore, the LCD includes a pixel electrode having a maximum aperture ratio and an excellent quality of the picture.
- While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the forgoing and other changes in form and details may be made therein without departing from the spirit of the invention.
Claims (20)
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US09/213,705 US6335781B2 (en) | 1998-12-17 | 1998-12-17 | Method for manufacturing an LCD in which a photoresist layer is at least 1.2 times thicker than the passivation layer |
US09/536,004 US6411356B1 (en) | 1998-12-17 | 2000-03-23 | Liquid crystal display device with an organic insulating layer having a uniform undamaged surface |
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US09/213,705 US6335781B2 (en) | 1998-12-17 | 1998-12-17 | Method for manufacturing an LCD in which a photoresist layer is at least 1.2 times thicker than the passivation layer |
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US09/536,004 Expired - Lifetime US6411356B1 (en) | 1998-12-17 | 2000-03-23 | Liquid crystal display device with an organic insulating layer having a uniform undamaged surface |
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US7535526B1 (en) * | 1999-05-26 | 2009-05-19 | Lg Display Co., Ltd. | Transmission-reflection type liquid crystal display device having a light transmitting region in a reflecting film |
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JP4677654B2 (en) * | 2000-04-19 | 2011-04-27 | 日本電気株式会社 | Transmission type liquid crystal display device and manufacturing method thereof |
JP4211250B2 (en) * | 2000-10-12 | 2009-01-21 | セイコーエプソン株式会社 | Transistor and display device including the same |
TW554221B (en) * | 2001-01-09 | 2003-09-21 | Matsushita Electric Ind Co Ltd | Liquid crystal display device and manufacturing method thereof |
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KR20050070325A (en) * | 2003-12-30 | 2005-07-07 | 엘지.필립스 엘시디 주식회사 | Lcd and method for manufacturing lcd |
TWI373097B (en) * | 2008-07-09 | 2012-09-21 | Au Optronics Corp | Method for fabricating thin film transistor array substrate |
TWI460864B (en) * | 2011-11-11 | 2014-11-11 | Au Optronics Corp | Thin film transistor and fabricating method thereof |
US10656148B2 (en) * | 2014-11-13 | 2020-05-19 | Pathogen Systems, Inc. | System and method for detecting pathogens on treated and untreated substrates using liquid crystal chromonic AZO dye |
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US5032883A (en) | 1987-09-09 | 1991-07-16 | Casio Computer Co., Ltd. | Thin film transistor and method of manufacturing the same |
JPH01281435A (en) | 1988-05-07 | 1989-11-13 | Seiko Epson Corp | Liquid crystal display device |
JP2808674B2 (en) | 1989-05-31 | 1998-10-08 | 日本電気株式会社 | Method for manufacturing semiconductor device |
JP2825878B2 (en) | 1989-10-27 | 1998-11-18 | 沖電気工業株式会社 | Trench forming method |
JP2924425B2 (en) | 1992-03-18 | 1999-07-26 | 三菱電機株式会社 | Manufacturing method of liquid crystal display device |
US6372534B1 (en) * | 1995-06-06 | 2002-04-16 | Lg. Philips Lcd Co., Ltd | Method of making a TFT array with photo-imageable insulating layer over address lines |
KR970011972A (en) * | 1995-08-11 | 1997-03-29 | 쯔지 하루오 | Transmission type liquid crystal display device and manufacturing method thereof |
US6001539A (en) * | 1996-04-08 | 1999-12-14 | Lg Electronics, Inc. | Method for manufacturing liquid crystal display |
KR100223153B1 (en) * | 1996-05-23 | 1999-10-15 | 구자홍 | Manufacturing method of active matrix liquid crystal display device and active matrix liquid crystal display device |
JP3317387B2 (en) * | 1996-06-03 | 2002-08-26 | シャープ株式会社 | Active matrix substrate and manufacturing method thereof |
KR100251091B1 (en) * | 1996-11-29 | 2000-04-15 | 구본준 | Method of manufacturing liquid crystal display device and liquid crystal display device |
US6011274A (en) * | 1997-10-20 | 2000-01-04 | Ois Optical Imaging Systems, Inc. | X-ray imager or LCD with bus lines overlapped by pixel electrodes and dual insulating layers therebetween |
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1998
- 1998-12-17 US US09/213,705 patent/US6335781B2/en not_active Expired - Lifetime
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US7535526B1 (en) * | 1999-05-26 | 2009-05-19 | Lg Display Co., Ltd. | Transmission-reflection type liquid crystal display device having a light transmitting region in a reflecting film |
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US6411356B1 (en) | 2002-06-25 |
US6335781B2 (en) | 2002-01-01 |
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