US20020031852A1 - Method of fabricating a liquid crystal display - Google Patents
Method of fabricating a liquid crystal display Download PDFInfo
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- US20020031852A1 US20020031852A1 US09/734,614 US73461400A US2002031852A1 US 20020031852 A1 US20020031852 A1 US 20020031852A1 US 73461400 A US73461400 A US 73461400A US 2002031852 A1 US2002031852 A1 US 2002031852A1
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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
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/133707—Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
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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
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133553—Reflecting elements
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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
- G02F1/136231—Active matrix addressed cells for reducing the number of lithographic steps
- G02F1/136236—Active matrix addressed cells for reducing the number of lithographic steps using a grey or half tone lithographic process
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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
- G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/139—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
- G02F1/1393—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells
Definitions
- the present invention relates in general to a method of fabricating a liquid crystal display (LCD).
- the present invention relates to a method of fabricating an alignment-control structure and a reflective layer of an LCD.
- Applied voltage and heat on a liquid crystal display changes the alignment of liquid crystals from an initial specific status to another status, and then the accompanied optical characteristics, such as double refraction, optical rotation, dichromatism, optical confusion and optical scattering will be transformed into visional variation.
- the liquid crystals can distribute substantial variation in optical characteristics with low voltage and low electric power consumption and without further working and shaping treatment.
- LCD has advantages of thin shape and light weight. Therefore, LCD plays an important role on the flat display market.
- the display mode of LCD is different from the type of the liquid crystals thereof.
- One mode named electrically controlled birefringence (ECB) employs applied electric field to control the multi-refraction characteristics of the liquid crystal, wherein nematic crystal having a negative anisotropy of its dielectric constant is utilized together with a vertical alignment layer.
- the applied voltage exceeds the critical voltage
- the liquid crystal molecules that are originally aligned perpendicular to the vertical alignment layer will rotate at an angle corresponding to the applied electric field.
- an alignment-control structure is fabricated on the LCD substrate to increase the amount of alignment domain in a pixel area. This is possible to secure a wide visual field angle and a high contrast.
- FIG. 1 is a cross-sectional schematic diagram of an LCD cell 10 according to the prior art.
- the LCD cell 10 comprises an upper glass substrate 12 , a lower glass substrate 14 , and a liquid crystal 16 with a negative anisotropy of its dielectric constant filling the space between the two glass substrates 12 , 14 .
- Two electrodes 18 , 22 and two vertical alignment layers 20 , 24 are respectively formed on the inner surface of the glass substrates 12 , 14
- two polarizers 26 , 28 are respectively formed on the outer surface of the glass substrates 12 , 14 .
- the upper glass substrate 12 serves as a color filter substrate.
- the lower glass substrate 14 serves as a thin film transistor (TFT) substrate where a plurality of TFTs and active matrix drive circuits are formed and the electrode 22 on the lower glass substrate 14 serves as a pixel electrode. Furthermore, the LCD cell 10 comprises a plurality of first protrusions 30 and second protrusions 32 respectively formed on the electrodes 18 , 22 to serve as the alignment-control structure.
- TFT thin film transistor
- FIG. 2 shows the variation in alignment of the liquid crystal molecules.
- the liquid crystal 16 having a negative anisotropy of dielectric constant is arranged between the vertical alignment layers 20 , 24 , all the liquid crystal molecules are aligned in the direction perpendicular to the vertical alignment layers 20 , 24 when no voltage is applied thereto.
- the liquid crystal molecules 16 A are aligned in the direction perpendicular to the glass substrates 12 , 14 .
- the liquid crystal molecules 16 B, 16 C positioned on the slopes of the protrusions 30 , 32 are aligned at an angle to the vertical alignment layers 20 , 24 .
- the crystal liquid 16 rotates toward the electric field wherein the alignment variation is shown by the arrows.
- part of the liquid crystal molecules rotate in the clockwise direction and another part of liquid crystal molecules rotate in the counterclockwise direction to accordingly increase the amount of alignment domain in a pixel area.
- FIG. 3A to FIG. 3C are schematic diagrams of a method of forming the alignment-control structure according to the prior art.
- a polymer resin layer 38 possessing photosensitive and thermosetting characteristics is coated on an electrode 36 of a glass substrate 34 , and then a curing treatment is performed on the polymer resin layer 38 .
- a photoresist layer with strip-shaped openings (not shown)
- the exposure process and the photolithography process are performed to form the polymer resin layer 38 as a plurality of strip-shaped protrusions 39 .
- a heat treatment is applied to make the polymer resin layer 38 reflow, and thereby the sharp-pointed edge of the protrusion 39 is rounded to complete the preferred alignment-control structure.
- the planar area on the top of the protrusion 39 with a round profile is too large.
- the liquid crystal molecules positioned thereon (such as the liquid crystal molecules 16 C shown in FIG. 2) is affected by a weaker electric field, and therefore sways toward the left and right since the aligned direction is not determined. This may result in spots or dark lines on the display screen and affect the display quality.
- the alignment-control structure is designed as an approximate triangle profile to decrease the planar area on the top of the protrusion as much as possible.
- this preferred protrusion is made of stacked layers by repeating deposition, photolithography and etching processes those complicated processes increase not only process cost but also difficulty in process property.
- An object of the present invention is to provide a method of fabricating an alignment-control structure having a triangle profile to solve the above-mentioned problems.
- the present invention provides a method of fabricating a liquid crystal display (LCD).
- a liquid crystal display LCD
- the pattern layer is formed as a plurality of first protrusions that are unconnected with each other and each of the first protrusions has a ladder profile.
- a dry etching process is performed to remove all of the first protrusions and part of the organic layer so as to form the remaining organic layer as a plurality of second protrusions corresponding to the first protrusions.
- the second protrusion has two sloped and intersected sidewalls.
- FIG. 1 is a cross-sectional schematic diagram of an LCD cell according to the prior art.
- FIG. 2 shows the variation in alignment of the liquid crystal molecules.
- FIG. 3A to FIG. 3C are schematic diagrams of a method of forming the alignment-control structure according to the prior art.
- FIG. 4A is a top view of an attenuated mask according to the present invention.
- FIG. 4B is a cross-sectional schematic diagram of the attenuated mask shown in FIG. 4A along line 4 B- 4 B.
- FIG. 4C illustrates the transparency of each area on the attenuated mask shown in FIG. 4B.
- FIG. 4D is a cross-sectional schematic diagram of a pattern by using the attenuated mask shown in FIG. 4B
- FIG. 5A to FIG. 5C are cross-sectional schematic diagrams of a method of fabricating a strip-shaped protrusion with a triangle profile according to the present invention.
- FIG. 6A to FIG. 6E are cross-sectional schematic diagrams of a reflective layer having a concave/convex profile according to the present invention.
- the present invention provides a method of fabricating an alignment-control structure, and more particularly, an attenuated mask is employed to define the sidewall of a top layer as a ladder profile.
- an attenuated mask is employed to define the sidewall of a top layer as a ladder profile.
- a selective etching process is performed to remove all the top layer and part of an underlying layer, wherein the underlying layer positioned below the thin area of the top layer is etched, and prior to that, positioned below the thick area, and finally the profile of the remaining underlying layer approximately becomes triangular. Consequently, except for the parameters of reactive gas, etching time and deposition depth, how to precisely control the profile of the underlying layer also greatly depends on controlling the ladder profile of the top layer (such as ladder number and ladder height). In the case of accurately determining the ladder profile, it depends on the pattern of the attenuated mask.
- FIG. 4A is a top view of an attenuated mask according to the present invention.
- FIG. 4B is a cross-sectional schematic diagram of the attenuated mask shown in FIG. 4A along line 4 B- 4 B.
- FIG. 4C illustrates the transparency of each area on the attenuated mask shown in FIG. 4B.
- FIG. 4D is a cross-sectional schematic diagram of a pattern by using the attenuated mask shown in FIG. 4B.
- An attenuated mask 40 comprises a quartz plate 42 and a cap layer that is defined as a first area 441 , a second area 442 surrounding the first area 441 and a third area 443 surrounding the second area 442 .
- the first area 441 made of transparent materials, has 100% transparency.
- the second area 442 preferred made of MoSi has 85 ⁇ 95% transparency to serve as a phase-shifting layer.
- the third area 443 preferred made of chromium (Cr) has approximately 0% transparency to serve as an opaque layer.
- the attenuated mask 40 can be fabricated with more than three areas having different transparencies from each other to shape the sidewall into many more ladders. Furthermore, if the relationship between the areas 441 ⁇ 443 are appropriately replaced, the attenuated mask 40 can be applied in shaping a negative-type photoresist to form the ladder profile.
- the ladder profile of the top layer can be accurately determined.
- the method of fabricating the underlying layer with a triangle profile in the present invention it can be more fully understood by reading the subsequent detailed description.
- FIGS. 5A to 5 C are cross-sectional schematic diagrams of a method of fabricating a strip-shaped protrusion with a triangle profile according to the present invention.
- an organic layer 54 is first coated on an electrode 52 of a glass substrate 50 followed by a curing treatment, and then a photoresist layer 56 is formed on the cured organic layer 54 .
- the photoresist layer 56 is defined and formed as a plurality of first protrusions 58 those are discontinuous to each other.
- the profile of the first protrusion 58 is shaped as a ladder, as shown in FIG. 5B.
- a dry etching process such as reactive ion etching (RIE) is performed to remove all the first protrusions 58 and part of the organic layer 54 .
- RIE reactive ion etching
- the two sidewalls of the second protrusion 59 are intersected inclines, and the planar area on the top of the second protrusion 59 is quite small and almost becomes a line. Consequently, utilizing the second protrusion 59 as the alignment-control structure has many advantages, such as avoiding spots or dark lines produced on the screen and increasing the displaying properties of the LCD.
- the method of forming the strip-shaped protrusions having a triangular profile is almost the same as the method described in the first embodiment except for replacing the photoresist layer 56 with photosensitive organic materials.
- a photosensitive organic layer (not shown) having a thickness equal to the sum of the depth of the organic layer 54 and the photoresist layer 56 is coated on the substrate 50 .
- the photolithography and etching processes described in the first embodiment can form the photosensitive organic layer as the second protrusions 59 having a triangular profile.
- FIGS. 6A to 6 E are cross-sectional schematic diagrams of a reflective layer having a concave/convex profile according to the present invention.
- a semiconductor substrate 60 comprises many semiconductor devices (not shown), such as TFTs, resistors or capacitors for driving a reflection-type LCD.
- An organic layer 62 is first coated on the semiconductor substrate 60 followed by a curing treatment, and then a photoresist layer 64 on the organic layer 62 .
- the photoresist layer 64 is formed as a plurality of first protrusions 66 those are connected and constitute a concave/convex profile, as shown in FIG. 6C.
- the attenuated mask 70 comprises a plurality of first areas 721 having 0 ⁇ 10% transparency and a plurality of second areas 722 having 70 ⁇ 80% transparency. Also, the traverse width of the first area 721 and the second area 722 is smaller than that of the areas 441 ⁇ 443 of the attenuated mask 40 .
- a dry etching process is performed to remove all of the first protrusions 66 and part of the organic layer 62 . Because the first protrusions 66 have concave areas and convex areas, the thinner area is earlier etched away to keep on downwardly etching the organic layer 62 until the thicker area of the first protrusions 66 is completely removed. As a result, the remaining organic layer 62 becomes a plurality of second protrusions 67 constituting a concave/convex profile and corresponding to the first protrusions 66 , as shown in FIG. 6D. Finally, a reflective layer 68 made of aluminum coated on the second protrusions 67 accordingly presents a concave/convex profile, as shown in FIG. 6E.
Abstract
Description
- 1. Field of the Invention
- The present invention relates in general to a method of fabricating a liquid crystal display (LCD). In particular, the present invention relates to a method of fabricating an alignment-control structure and a reflective layer of an LCD.
- 2. Description of the Related Art
- Applied voltage and heat on a liquid crystal display (LCD) changes the alignment of liquid crystals from an initial specific status to another status, and then the accompanied optical characteristics, such as double refraction, optical rotation, dichromatism, optical confusion and optical scattering will be transformed into visional variation. Compared with the electric-optical materials used in other optical devices, the liquid crystals can distribute substantial variation in optical characteristics with low voltage and low electric power consumption and without further working and shaping treatment. Also, LCD has advantages of thin shape and light weight. Therefore, LCD plays an important role on the flat display market.
- The display mode of LCD is different from the type of the liquid crystals thereof. One mode named electrically controlled birefringence (ECB) employs applied electric field to control the multi-refraction characteristics of the liquid crystal, wherein nematic crystal having a negative anisotropy of its dielectric constant is utilized together with a vertical alignment layer. When the applied voltage exceeds the critical voltage, the liquid crystal molecules that are originally aligned perpendicular to the vertical alignment layer will rotate at an angle corresponding to the applied electric field. Besides, for further controlling the alignment of the liquid crystal molecules, an alignment-control structure is fabricated on the LCD substrate to increase the amount of alignment domain in a pixel area. This is possible to secure a wide visual field angle and a high contrast.
- Please refer to FIG. 1. FIG. 1 is a cross-sectional schematic diagram of an
LCD cell 10 according to the prior art. TheLCD cell 10 comprises anupper glass substrate 12, alower glass substrate 14, and aliquid crystal 16 with a negative anisotropy of its dielectric constant filling the space between the twoglass substrates vertical alignment layers glass substrates polarizers glass substrates upper glass substrate 12 serves as a color filter substrate. Thelower glass substrate 14 serves as a thin film transistor (TFT) substrate where a plurality of TFTs and active matrix drive circuits are formed and the electrode 22 on thelower glass substrate 14 serves as a pixel electrode. Furthermore, theLCD cell 10 comprises a plurality offirst protrusions 30 andsecond protrusions 32 respectively formed on the electrodes 18, 22 to serve as the alignment-control structure. - Please refer to FIG. 2. FIG. 2 shows the variation in alignment of the liquid crystal molecules. In the case where the
liquid crystal 16 having a negative anisotropy of dielectric constant is arranged between thevertical alignment layers vertical alignment layers liquid crystal molecules 16A are aligned in the direction perpendicular to theglass substrates liquid crystal molecules protrusions vertical alignment layers LCD cell 10, thecrystal liquid 16 rotates toward the electric field wherein the alignment variation is shown by the arrows. As a result, part of the liquid crystal molecules rotate in the clockwise direction and another part of liquid crystal molecules rotate in the counterclockwise direction to accordingly increase the amount of alignment domain in a pixel area. - Please refer to FIG. 3A to FIG. 3C. FIG. 3A to FIG. 3C are schematic diagrams of a method of forming the alignment-control structure according to the prior art. First, a
polymer resin layer 38 possessing photosensitive and thermosetting characteristics is coated on anelectrode 36 of aglass substrate 34, and then a curing treatment is performed on thepolymer resin layer 38. Next, by using a photoresist layer with strip-shaped openings (not shown), the exposure process and the photolithography process are performed to form thepolymer resin layer 38 as a plurality of strip-shaped protrusions 39. Finally, a heat treatment is applied to make thepolymer resin layer 38 reflow, and thereby the sharp-pointed edge of theprotrusion 39 is rounded to complete the preferred alignment-control structure. - However, the planar area on the top of the
protrusion 39 with a round profile is too large. The liquid crystal molecules positioned thereon (such as theliquid crystal molecules 16C shown in FIG. 2) is affected by a weaker electric field, and therefore sways toward the left and right since the aligned direction is not determined. This may result in spots or dark lines on the display screen and affect the display quality. In order to solve the problem, the alignment-control structure is designed as an approximate triangle profile to decrease the planar area on the top of the protrusion as much as possible. Unfortunately, this preferred protrusion is made of stacked layers by repeating deposition, photolithography and etching processes those complicated processes increase not only process cost but also difficulty in process property. - An object of the present invention is to provide a method of fabricating an alignment-control structure having a triangle profile to solve the above-mentioned problems.
- The present invention provides a method of fabricating a liquid crystal display (LCD). First, an organic layer is formed on a glass substrate and then a pattern layer is formed on the organic layer. Next, by employing an attenuated mask, the pattern layer is formed as a plurality of first protrusions that are unconnected with each other and each of the first protrusions has a ladder profile. Next, a dry etching process is performed to remove all of the first protrusions and part of the organic layer so as to form the remaining organic layer as a plurality of second protrusions corresponding to the first protrusions. The second protrusion has two sloped and intersected sidewalls.
- This and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings.
- The present invention can be more fully understood by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein:
- FIG. 1 is a cross-sectional schematic diagram of an LCD cell according to the prior art.
- FIG. 2 shows the variation in alignment of the liquid crystal molecules.
- FIG. 3A to FIG. 3C are schematic diagrams of a method of forming the alignment-control structure according to the prior art.
- FIG. 4A is a top view of an attenuated mask according to the present invention.
- FIG. 4B is a cross-sectional schematic diagram of the attenuated mask shown in FIG. 4A along
line 4B-4B. - FIG. 4C illustrates the transparency of each area on the attenuated mask shown in FIG. 4B.
- FIG. 4D is a cross-sectional schematic diagram of a pattern by using the attenuated mask shown in FIG. 4B
- FIG. 5A to FIG. 5C are cross-sectional schematic diagrams of a method of fabricating a strip-shaped protrusion with a triangle profile according to the present invention.
- FIG. 6A to FIG. 6E are cross-sectional schematic diagrams of a reflective layer having a concave/convex profile according to the present invention.
- The present invention provides a method of fabricating an alignment-control structure, and more particularly, an attenuated mask is employed to define the sidewall of a top layer as a ladder profile. Next, a selective etching process is performed to remove all the top layer and part of an underlying layer, wherein the underlying layer positioned below the thin area of the top layer is etched, and prior to that, positioned below the thick area, and finally the profile of the remaining underlying layer approximately becomes triangular. Consequently, except for the parameters of reactive gas, etching time and deposition depth, how to precisely control the profile of the underlying layer also greatly depends on controlling the ladder profile of the top layer (such as ladder number and ladder height). In the case of accurately determining the ladder profile, it depends on the pattern of the attenuated mask.
- Please refer to FIGS. 4A to4D. FIG. 4A is a top view of an attenuated mask according to the present invention. FIG. 4B is a cross-sectional schematic diagram of the attenuated mask shown in FIG. 4A along
line 4B-4B. FIG. 4C illustrates the transparency of each area on the attenuated mask shown in FIG. 4B. FIG. 4D is a cross-sectional schematic diagram of a pattern by using the attenuated mask shown in FIG. 4B. Anattenuated mask 40 comprises aquartz plate 42 and a cap layer that is defined as afirst area 441, asecond area 442 surrounding thefirst area 441 and athird area 443 surrounding thesecond area 442. Thefirst area 441, made of transparent materials, has 100% transparency. Thesecond area 442 preferred made of MoSi has 85˜95% transparency to serve as a phase-shifting layer. Thethird area 443 preferred made of chromium (Cr) has approximately 0% transparency to serve as an opaque layer. When theattenuated mask 40 is utilized to perform the photolithography process on a positive-type photoresist 46, theareas 441˜443 having different transparencies make corresponding areas on thephotoresist 46 respectively receive different light intensity to achieve an incomplete exposure result. Therefore, each etched depth of the corresponding areas on thephotoresist 46 is different and the sidewall of thephotoresist 46 can be finally formed as a ladder profile. Also, theattenuated mask 40 can be fabricated with more than three areas having different transparencies from each other to shape the sidewall into many more ladders. Furthermore, if the relationship between theareas 441˜443 are appropriately replaced, theattenuated mask 40 can be applied in shaping a negative-type photoresist to form the ladder profile. - In accordance with the above-mentioned method, the ladder profile of the top layer can be accurately determined. As to the method of fabricating the underlying layer with a triangle profile in the present invention, it can be more fully understood by reading the subsequent detailed description.
- First Embodiment
- Please refer to FIGS. 5A to5C. FIGS. 5A to 5C are cross-sectional schematic diagrams of a method of fabricating a strip-shaped protrusion with a triangle profile according to the present invention. As shown in FIG. 5A, an
organic layer 54 is first coated on anelectrode 52 of aglass substrate 50 followed by a curing treatment, and then aphotoresist layer 56 is formed on the curedorganic layer 54. Next, by using theattenuated mask 40 shown in FIG. 4, thephotoresist layer 56 is defined and formed as a plurality offirst protrusions 58 those are discontinuous to each other. In accordance with the design of theareas 441˜443 of theattenuated mask 40, such as transverse width, position and transparency, the profile of thefirst protrusion 58 is shaped as a ladder, as shown in FIG. 5B. - Next, a dry etching process, such as reactive ion etching (RIE) is performed to remove all the
first protrusions 58 and part of theorganic layer 54. Because thefirst protrusion 58 has two areas of different thickness, the thinner area of thefirst protrusion 58 is earlier etched away to keep on downwardly etching theorganic layer 54 till the thicker area of thefirst protrusion 58 is completely removed. As a result, the remainingorganic layer 54 becomes a plurality ofsecond protrusions 59 having triangle profiles and corresponding to thefirst protrusions 58. The two sidewalls of thesecond protrusion 59 are intersected inclines, and the planar area on the top of thesecond protrusion 59 is quite small and almost becomes a line. Consequently, utilizing thesecond protrusion 59 as the alignment-control structure has many advantages, such as avoiding spots or dark lines produced on the screen and increasing the displaying properties of the LCD. - Second Embodiment
- In the second embodiment of the present invention, the method of forming the strip-shaped protrusions having a triangular profile is almost the same as the method described in the first embodiment except for replacing the
photoresist layer 56 with photosensitive organic materials. In this case, a photosensitive organic layer (not shown) having a thickness equal to the sum of the depth of theorganic layer 54 and thephotoresist layer 56 is coated on thesubstrate 50. After performing the curing treatment on the photosensitive organic layer, the photolithography and etching processes described in the first embodiment can form the photosensitive organic layer as thesecond protrusions 59 having a triangular profile. - Third Embodiment
- The present invention not only applies to the formation of the alignment-control structure, but also to the formation of a reflective layer of a reflective-type LCD. Please refer to FIGS. 6A to6E. FIGS. 6A to 6E are cross-sectional schematic diagrams of a reflective layer having a concave/convex profile according to the present invention. As shown in FIG. 6B, a
semiconductor substrate 60 comprises many semiconductor devices (not shown), such as TFTs, resistors or capacitors for driving a reflection-type LCD. Anorganic layer 62 is first coated on thesemiconductor substrate 60 followed by a curing treatment, and then aphotoresist layer 64 on theorganic layer 62. - Next, by using an attenuated mask70 (as shown in FIG. 6A), the
photoresist layer 64 is formed as a plurality offirst protrusions 66 those are connected and constitute a concave/convex profile, as shown in FIG. 6C. In order to define the concave/convex profile, theattenuated mask 70 comprises a plurality offirst areas 721 having 0˜10% transparency and a plurality ofsecond areas 722 having 70˜80% transparency. Also, the traverse width of thefirst area 721 and thesecond area 722 is smaller than that of theareas 441˜443 of theattenuated mask 40. - Next, a dry etching process is performed to remove all of the
first protrusions 66 and part of theorganic layer 62. Because thefirst protrusions 66 have concave areas and convex areas, the thinner area is earlier etched away to keep on downwardly etching theorganic layer 62 until the thicker area of thefirst protrusions 66 is completely removed. As a result, the remainingorganic layer 62 becomes a plurality ofsecond protrusions 67 constituting a concave/convex profile and corresponding to thefirst protrusions 66, as shown in FIG. 6D. Finally, areflective layer 68 made of aluminum coated on thesecond protrusions 67 accordingly presents a concave/convex profile, as shown in FIG. 6E. - Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims (23)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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TW89118763 | 2000-09-13 | ||
TW089118763A TWI240811B (en) | 2000-09-13 | 2000-09-13 | Manufacturing method of liquid crystal display device |
TW89118763A | 2000-09-13 |
Publications (2)
Publication Number | Publication Date |
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US20020031852A1 true US20020031852A1 (en) | 2002-03-14 |
US6407790B1 US6407790B1 (en) | 2002-06-18 |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6455339B1 (en) * | 2000-11-30 | 2002-09-24 | Hannstar Display Corp. | Method for fabricating protrusion of liquid crystal display |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
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JP3097656B2 (en) * | 1998-05-13 | 2000-10-10 | 日本電気株式会社 | Liquid crystal display device and method of manufacturing the same |
KR20010082831A (en) * | 2000-02-21 | 2001-08-31 | 구본준, 론 위라하디락사 | Method of Fabricating Liquid Crystal Display Device |
TWI225556B (en) * | 2000-09-13 | 2004-12-21 | Au Optronics Corp | Manufacturing method of reflective liquid crystal display |
JP2002162646A (en) * | 2000-09-14 | 2002-06-07 | Sony Corp | Reflection type liquid crystal display device |
JP2002107744A (en) * | 2000-09-27 | 2002-04-10 | Koninkl Philips Electronics Nv | Electrode forming method, pixel electrode forming method, and liquid crystal display device |
JP3875125B2 (en) * | 2001-04-11 | 2007-01-31 | シャープ株式会社 | Liquid crystal display |
JP3895952B2 (en) * | 2001-08-06 | 2007-03-22 | 日本電気株式会社 | Transflective liquid crystal display device and manufacturing method thereof |
CN112596305A (en) * | 2020-12-10 | 2021-04-02 | 惠科股份有限公司 | Liquid crystal panel and production control method thereof |
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JPS58125084A (en) * | 1982-01-21 | 1983-07-25 | 株式会社東芝 | Liquid crystal display and manufacture thereof |
US6335150B1 (en) * | 2000-12-05 | 2002-01-01 | Wintek Corporation | Manufacturing method for reflecting panel of reflective liquid crystal display |
-
2000
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US6455339B1 (en) * | 2000-11-30 | 2002-09-24 | Hannstar Display Corp. | Method for fabricating protrusion of liquid crystal display |
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US6407790B1 (en) | 2002-06-18 |
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