KR20030020506A - Liquid Crystal Display Device and the method thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display device and a method for fabricating the liquid crystal display device are provided to increase spacial sizes among pixel electrodes toward edges of pixel areas in the shape of matrix by using a photo mask widening in proportion to a distance from the centers to the edges of the pixel areas, thereby simplifying the permeation of a development solution. CONSTITUTION: A liquid crystal display device includes gate and data wires(31,32) formed on a first substrate(30) and defining pixel areas in the shape of matrix, switching elements formed on intersections between the gate and data wires, a protecting layer formed on the switching elements, and pixel electrodes(37) formed on the protecting layer, the size of the pixel electrodes decreasing as farther from the centers of the pixel areas in the matrix shape.

Description

Liquid crystal display device and method for manufacturing same

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a mask for improving a real residue generated when forming a pixel electrode.

In general, it is widely known that various patterns of the liquid crystal display are formed by photolithography. The photolithography process is a process for forming a desired pattern on a substrate. First, a photoresist film is formed on a film on which a specific pattern on a photomask formed on a surface or a predetermined layout of a washed and dried substrate is formed, and an X-ray A portion of the photoresist film whose solubility changes by irradiation with light such as ultraviolet rays or the like is exposed to the light beam to remove a portion having high solubility with respect to a developer to form a photoresist pattern, and to expose the film to be formed. The formed portions are removed by etching to form various patterns such as wires and electrodes, and the remaining developer is washed to form a desired pattern.

On the other hand, a photoresist coating is performed, where the cleaned substrate is placed on a spin chuck, the photoresist is dispensed while the substrate is rotated or stopped, and then the spin chuck is spun at high speed. Rotate to coat the photoresist to a uniform thickness. The photoresist is exposed to light by an alignment process and an exposure process for imaging to actually transfer the pattern onto the substrate. The photoresist on the substrate after the exposure process is selectively dissolved by a developer. At this time, there are two types of photoresist.

FIG. 1A is a photomask process diagram using a positive photoresist, and FIG. 1B is a photomask process diagram using a negative photoresist.

First, as illustrated in FIG. 1A, a pattern is formed using a positive photoresist 2. The positive photoresist 2 is composed of a solvent, a sensitizer (PAC), and a resin (Novolak resin), and the PAC is cured when light is received in a state in which a soluble resin and a soluble photosensitive agent are present as a mixture. It is converted into carboxylic acid, so that it is very soluble in alkaline aqueous solution (development solution). Therefore, it is easy to manufacture a sample, and the line width is possible even at 0.5 micrometer or less, and is widely used for the general liquid crystal display element process.

Second, as shown in FIG. 1B, a pattern is formed using a negative photoresist 3. The negative photoresist (3) is composed of a solvent, a photoresist (bis-aryldiazide), synthetic rubber, the photoresist is a material that does not wash away in the solvent developer by cross-linking the rubber component when exposed to light Consists of. Therefore, since the cross section is stretched like a rubber, the cross section profile is changed during fabrication of the sample, so that the photomask process is impossible at the line width of 1 μm or less.

Therefore, in general, since the delicate work is required in the manufacture of semiconductors and the manufacture of liquid crystal display devices, the positive photoresist 2 is mainly used.

In addition, the substrate after the alignment and exposure process using the photomask is subjected to a development process for selectively dissolving the photoresist 2 and 3. Immersion method of dipping the substrate into the developer tank in batch unit or passing the substrate through the developer tank one by one, and spray spray method by continuously spraying the developer onto the substrate. In order to make up for the disadvantages of the immersion method and the spray method, the spray-puddle method of the combined method is used.

The following variables affect the development process. Since the concentration of the developer is related to the amount of reactive species (NaOH, KOH, TMAH, TEAH) that determines how well it can react with the photoresist (2) (3) during development, it has a great influence on the actual development speed. In relation to the reaction time, the longer the developing time is, the lower the exposure amount is possible to reproduce the size of the same pattern. However, if it is too long, the upper part of the pattern that has been exposed to the developer for a long time is eroded and the profile becomes bad. Moreover, the temperature of the developer is related to the reaction rate, so constant temperature control is very important.

Hereinafter, a conventional liquid crystal display device and a manufacturing method thereof will be described in detail with reference to the accompanying drawings.

2 is a plan view of a liquid crystal display device according to the prior art.

Referring to FIG. 2, a conventional liquid crystal display device is formed on a plurality of pixel regions defined by a plurality of gate lines 10 and a plurality of data lines 12 on a first substrate 6 and in each of the pixel regions. And a plurality of thin film transistors (not shown) which switch according to the signal of the gate wiring and apply the signal of the data wiring 12 to the pixel electrode 8. Here, a portion corresponding to the gate wiring 10 and the data wiring 12 corresponds to a boundary between the pixel electrode 8 and the pixel electrode 8, which are to be independent of each other at the edge of the first substrate. The real residue 9 in which the pixel electrodes 8 are connected to each other is generated. Let's look at the manufacturing process of the liquid crystal display device to see the cause of the actual residue.

3 is a cross-sectional view of a portion I to I 'of the liquid crystal display device of the prior art.

As shown in FIG. 3, the cross-sectional structure of the liquid crystal display according to the related art is protruded from the first substrate 6 and the second substrate 20 and the gate wiring (10 of FIG. 2) on the first substrate 6. The gate electrode 11, the gate insulating film 13 formed on the entire surface of the substrate including the gate electrode 11, and the semiconductor layer 14 formed in an island shape on the gate insulating film 13 above the gate electrode 11. ) And an ohmic contact layer 15 formed on both sides of the semiconductor layer 14, and source / drain electrodes 16a and 16b to form a thin film transistor (Thin Film Transistor; TFT). In addition, a passivation layer 17 is formed over the entire first substrate 6 including the thin film transistor, and a pixel electrode 8 is formed on the passivation layer 17 so as to be connected to the drain electrode 16b. The alignment layer 18 is formed on the front surface of the substrate including the electrode 8 for the regular arrangement of liquid crystals.

In addition, the light blocking layer 21 for blocking light corresponding to the gate wiring, the data wiring 12 and the thin film transistor on the second substrate 20 and the light blocking layer 21 may be colored. A regular array of liquid crystals is formed on the color filter layer 22 formed to implement the common electrode 23 formed to have a potential difference from the pixel electrode 8 of the first substrate 6, and the common electrode 23. The alignment film 18 formed for this purpose is provided. Spacers (not shown) scattered on opposing surfaces of the first substrate 6 and the second substrate 20 to maintain a predetermined space of the first substrate 6 and the second substrate 20. In addition, there is a liquid crystal 19 injected between the first substrate 6 and the second substrate 20.

A method of manufacturing a liquid crystal display device having such a structure will be described. A gate wiring including the gate electrode 11 in one direction at regular intervals is formed on a cleaned quartz or glass transparent substrate, and the gate wiring is formed. The gate insulating layer 13 is formed on the entire surface of the transparent substrate. After depositing the semiconductor layer 14 and the ohmic contact layer 15 of polysilicon or amorphous silicon on the gate insulating layer 13, the semiconductor layer 14 may have an island shape only on the gate electrode 11. And selectively removes the ohmic contact layer 15. Next, a metal is deposited on the front surface and selectively removed to form a data line having a source electrode 16a and a drain electrode 16b. After forming the source electrode 16a and the drain electrode 16b, the ohmic contact layer 15 between the source electrode 16a and the drain electrode 16b is removed to manufacture a thin film transistor. In addition, a protective layer 17 such as an organic insulating material of benzocyclobutene (BCB) or an inorganic insulating material of SiN _x and SiO _x is deposited on the entire surface, and a contact hole is formed to expose the drain electrode 16b.

A transparent conductive metal such as indium tin oxide (ITO) or tin oxide (TO) is deposited on the protective layer 17 by a sputtering method. In this case, the protective layer 17 and the indium-tin oxide (ITO) are buffer layers made of silicon oxide for adhesion between the protective layer 17 and indium-tin oxide (ITO) or tin oxide (TO). Alternatively, it may be formed between a conductive metal such as TO (Tin Oxide).

The deposited transparent conductive metal such as indium tin oxide (ITO) or tin oxide (TO) is patterned by photolithography to form the pixel electrode 8. The pixel electrode 8 is formed in contact with the drain electrode 16b to cover the pixel region. The transparent conductive metal, such as indium tin oxide (ITO) or tin oxide (TO), has a large and uniform particle, so that the etching rate is stable when the pixel electrode is formed.

However, in the above-described method of manufacturing a liquid crystal display device according to the related art, since the intervals between the adjacent pixel electrodes 8 are very narrow, residues of transparent conductive metal are generated during patterning, so that the defects are not electrically separated. There is a problem that the yield is lowered. The residue is found more at the edge of the cell (not shown).

Regardless of its product size, the reason is likely to arise from making a plurality of thin film transistor arrays, that is, a plurality of cells, on a standardized disk substrate.

4 is a plan view of a conventional liquid crystal display device.

As shown in FIG. 4, the first substrate has a plurality of cells 7 formed therein, a space 24 having a boundary between each of the cells 7 and 7, and a pixel area formed vertically and horizontally in the cells. The data wiring 12 and the gate wiring 10 are defined.

Here, the formation process of the pixel electrode (8 in FIG. 3) will be described in more detail. A photo on a conductive transparent metal such as indium tin oxide (ITO) or tin oxide (TO) deposited on the first substrate 6 will be described. The resist is evenly coated, a mask having a predetermined size of the pixel region and a plurality of patterns of the cells is placed on the first substrate 6 at the correct position, and the photoresist is exposed by light irradiation. After the first substrate 6 is immersed in the developer, the developer is removed and washed. In this case, the space outside the cell 7, that is, the area where the cell 7 and the cell 7 are adjacent to each other, is a position to cut between the cells 7, and when the positive photoresist 2 is used. The positive photoresist 2 coated on the blank should be removed.

Therefore, when developing the coated photoresist 2 with a developer in the photolithography process for forming the pixel electrode 8, since the blank 24 is a portion where the transparent metal should be removed, the developer in this portion is large. The photoresist 2 has a concentration and can therefore affect the entire periphery of each cell. Therefore, residues may occur between the pixel electrode 8 and the pixel electrode 8 at the edge of the cell 7 during the photolithography process of the pixel electrode 8.

That is, as the photoresist developing solution used in the patterning of the pixel electrode goes to the edge of the cell 7, the concentration of the photoresist increases, resulting in a decrease in developing power, thereby generating a real residue 9 around the edge.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In the mask for patterning the pixel electrode, the distance between the pixel electrode patterns becomes farther toward the edge, that is, the pixel electrode is patterned so as to become smaller, thereby forming a pixel electrode. It is an object of the present invention to provide a liquid crystal display device and a method for manufacturing the same, which can eliminate a large amount of real residue occurring at the edge.

1A is a photomask process diagram using positive photoresist.

1B is a photomask process diagram using negative photoresist.

2 is a plan view of a liquid crystal display device according to the prior art

3 is a cross-sectional view taken along line II ′ of FIG. 1.

4 is a plan view of a first substrate having a plurality of liquid crystal display panel;

5 is a plan view of a liquid crystal display device according to the present invention;

FIG. 6 is a cross-sectional view taken along line II ′ of FIG. 5.

Explanation of symbols for main parts of the drawings

1: mask 2: positive photoresist

3: negative photoresist 4: mask glass

5 substrate 6 first substrate

7 cell 8 pixel electrode

9: thread residue 10: gate wiring

11 gate electrode 12 data wiring

13 gate insulating film 14 semiconductor layer

15: ohmic contact layer 16a: source electrode

16b: drain electrode 17: protective layer

18: alignment film 19: liquid crystal

20: second substrate 21: light shielding layer

22: color filter layer 23: common electrode

24: blank

30: first substrate 31: gate wiring

32: data wiring 33: gate electrode

34a: source electrode 34b: drain electrode

36 thin film transistor 37 pixel electrode

38 gate insulating film 39 semiconductor layer

40: ohmic contact layer 41: protective layer

42 contact hole 43 alignment layer

44: second substrate 45: light shielding layer

46 color filter layer 47 common electrode

48: spacer 49: liquid crystal

50: cell

According to an exemplary embodiment of the present invention, a liquid crystal display device includes: a gate line and a data line formed on a first substrate to define pixel regions in a matrix form, and a switching element formed at an intersection of the gate line and the data line; And a protective layer formed on the switching element and a pixel electrode formed on the protective layer and decreasing in size as it moves away from the center of the pixel areas in the matrix form.

In addition, the manufacturing method of the liquid crystal display device of the present invention for achieving the above object comprises the steps of forming a gate wiring with a gate electrode on the first substrate and forming a gate insulating film on the front surface, Forming a semiconductor layer on the semiconductor layer, forming a data wiring in a direction perpendicular to the gate wiring so that source and drain electrodes are positioned on both sides of the semiconductor layer, and forming a protective layer on the entire surface of the substrate and forming the gate Another aspect is that the method includes forming a plurality of pixel electrodes in a matrix form, the size of which decreases as the distance from the center of the pixel regions of the matrix form defined by the wiring and the data line.

In the photolithography process of the pixel electrode forming process, a real mask is removed by using a photomask in which the space interval between the pixel electrodes increases in proportion to the distance as the distance from the center of the pixel region in the matrix form increases.

Hereinafter, a liquid crystal display device and a method of manufacturing the same according to the present invention will be described in detail with reference to the drawings.

5 is a plan view of the structure of the liquid crystal display device of the present invention.

In the liquid crystal display of the present invention, pixel areas defined by a plurality of gate lines 31 and data lines 32 are provided on the first substrate 30, and pixel electrodes 37 are formed in each pixel area. The thin film transistors 36 arranged in a matrix form and switched according to the driving signals of the gate lines 31 to apply the data signals of the data lines 32 to the pixel electrodes 37 are arranged. In this case, the size of the pixel electrode 37 decreases as the distance from the center of the pixel areas increases. That is, the distance between each pixel electrode 37 is increased.

6 is a sectional view taken along the line II-II 'of FIG.

As shown in FIG. 6, the first substrate 30 includes a first substrate 30 made of glass, a gate electrode 33 formed on the first substrate 30, and the gate electrode 33. The gate insulating layer 38 formed on the entire surface, the semiconductor layer 39 formed in an island shape on the gate insulating layer 38 above the gate electrode 33, and the semiconductor layer to reduce the contact resistance of the semiconductor layer. (39) an ohmic contact layer 40 formed on both sides, a source electrode 34a and a drain electrode 34b formed on the ohmic contact layer 40, and a source electrode 34a and a drain electrode 34b. The protective layer 41 formed on the entire surface of the first substrate 30 including the source electrode 34a and the drain electrode 34b and the drain electrode 34b for electrical contact. A pixel formed on the protective layer 41 including the contact hole 42 formed inside the 41 and the contact hole 42. There is electrode 37 and the alignment film 43 formed on the entire surface of the first substrate 30 including the pixel electrode 37.

In addition, the second substrate 44 corresponding to the first substrate 30 and the gate wiring 31, the data wiring 32, and the thin film transistor 36 may be formed on the second substrate 44. A light blocking layer 45 to block light of a portion, a color filter layer 46 formed to overlap the light blocking layer 45 to implement RG B colors on the light blocking layer 45, and the first The common electrode 47 formed on the color filter layer 46 and the alignment layer 43 formed on the common electrode 47 are provided to have a potential difference from the pixel electrode 37 of the substrate 30. In addition, in order to maintain a predetermined space between the first substrate 30 and the second substrate 44 and the spacer 48 dispersed on the opposite surface of the first substrate 30 and the second substrate 44 and The liquid crystal 49 is injected between the first substrate 30 and the second substrate 44. In this case, an overcoat layer (not shown) may be formed between the color filter layer 46 and the common electrode 47 to planarize the color filter layer 46 and the light blocking layer 45.

Looking at the manufacturing process of the liquid crystal display device as follows.

First, the first substrate 30 is formed by depositing a metal on the cleaned glass substrate using a sputtering method and selectively removing the metal by a photolithography process to form a gate wiring 31 and a gate electrode 33. An insulating film insulating the gate wiring 31 and the gate electrode 33 is deposited on the entire surface of the first substrate 30 to form a gate insulating film 38, and the semiconductor layer 39 of polycrystalline silicon or amorphous silicon is formed on the gate insulating film. ) And the ohmic contact layer 40, and then selectively remove the semiconductor layer 39 and the ohmic contact layer 40 to have an island shape only on the gate electrode. A metal is deposited on the entire surface, and then selectively removed while leaving both sides on the semiconductor layer 39 to form a data line 32 having source / drain electrodes 34a and 34b. In addition, the ohmic contact layer 40 between the source / drain electrodes 34a and 34b is removed to manufacture the thin film transistor 36.

In addition, a protective layer 41 is formed over the entire surface of the first substrate 30 including the source / drain electrodes 34a and 34b to insulate and planarize the data line 32. To expose the 34b), the protective layer 41 is formed to form a contact hole 42, and a transparent electrode ITO is deposited on the entire surface of the first substrate to form the contact electrode 42. The drain electrode 34b is formed through the contact hole 42. And a plurality of pixel electrodes 37 (ITO) to be connected to each other, and an alignment layer 43 is formed on the entire surface of the first substrate 30 including the pixel electrodes 37 for regular arrangement of liquid crystals. Form. Here, the photolithography process is performed by using a mask in which the distance between the pixel electrodes 37 increases in proportion to the distance as the distance from the center of the pixel regions in the matrix form after the photoresist process during the formation of the pixel electrode 37. Do it. That is, the area of the pixel electrode 37 is made smaller from the center of each of the plurality of thin film transistor arrays on the first substrate 30 toward the edge portion.

Accordingly, the second substrate 44 is not only corresponding portions of the gate wiring 31 and the data wiring 32 and the thin film transistor 36 formed on the first substrate 30, but also from the center to the edge of the thin film transistor array. A light shielding layer 45 is formed to block light leaking according to the size of the pixel electrode 37 which is gradually reduced, and RG B color is formed at a portion corresponding to the pixel electrode 37 between the light shielding layers 45. The color filter layer 46 is formed to be formed, and common to induce a voltage difference between the pixel electrode 37 driven by the thin film transistor 36 of the first substrate 30 on the color filter layer 46. An electrode 47 (ITO) is formed, and an alignment layer 43 is formed to align the liquid crystal 49. Similarly, when the light blocking layer 45 and the color filter layer 46 are formed, the light blocking layer 45 becomes wider toward the edges of the pixel areas in the matrix form according to the size change of the pixel electrode 37. do. Therefore, the color filter layer 46 has a relatively small area.

As a result, when the pixel electrode 37 is processed, using the mask in which the distance between the pixel electrodes 37 increases in proportion to the distance from the center of the pixel regions in the matrix form is the pixel region in the matrix form. This is because the gap between the pixel electrodes 37 is increased toward the edges, thereby facilitating the penetration of the developer, thereby reducing the occurrence of the actual residue. The real residue is a phenomenon in which thin residues remain between the patterns generated in the pixel pattern having a square lattice arrangement. The real residue is mainly a pixel array pixel mosaic. Since an array edge is used, a mask that reduces the pattern corresponding to the pixel electrode 37 as the distance from the center of the pixel mosaic array edge, which is the pixel array, is reduced, thereby preventing the occurrence of real residue. can do.

As described above, the liquid crystal display of the present invention has the following effects.

In the case of forming a pixel electrode, when using a photomask in which the distance between the pixel electrode and the pixel electrode is increased in proportion to the distance from the center of the pixel regions of the matrix type to the edge, the pixel electrode toward the edge of the pixel regions of the matrix type By increasing the size of the liver, the penetration of the developer can be facilitated, and the occurrence of real residue can be reduced.

Claims (11)

A gate wiring and a data wiring formed on the first substrate to define pixel regions in a matrix form; A switching element formed at an intersection of the gate wiring and the data wiring; A protective layer formed on the switching element, And a pixel electrode formed on the passivation layer, the pixel electrode of which decreases in size as it moves away from the center of the matrix pixel areas. The method of claim 1, The switching device is a liquid crystal display device, characterized in that the thin film transistor. The method of claim 2, The thin film transistor includes a gate electrode, a source electrode and a drain electrode. The method of claim 1, And the first substrate includes a plurality of pixel areas in the matrix form. The method of claim 1, And a light shielding layer on a second substrate corresponding to the first substrate. The method of claim 1, And a color filter layer on a second substrate corresponding to the first substrate. Forming a gate wiring having a gate electrode on the first substrate and forming a gate insulating film on the front surface thereof; Forming a semiconductor layer on the gate insulating film; Forming a data line in a direction perpendicular to the gate line such that source and drain electrodes are positioned on both sides of the semiconductor layer; Forming a protective layer on the entire surface of the substrate and forming a plurality of pixel electrodes in a matrix form, the size of which decreases as the distance from the center of the pixel regions of the matrix form defined by the gate lines and the data lines. Characterized in that the liquid crystal display device manufacturing method. The method of claim 7, wherein, when forming the pixel electrode, a mask having a pattern size corresponding to the pixel electrode decreases from the center of the matrix area to the edge. The method of claim 7, wherein a light shielding layer is further formed on a second substrate corresponding to the first substrate. 8. The method of claim 7, wherein a color filter layer is further formed on a second substrate corresponding to the first substrate. The method of claim 10, wherein the color filter layer is formed to have the same size as the corresponding pixel electrode.