JPH06235936A - Manufacture for liquid crystal display element - Google Patents

Abstract

PURPOSE:To manufacture a liquid crystal display element having good pattern reproducibility of a black matrix portion by resolving the problem of defective patterning such as cracks, peeling, and residues of a pattern generated on a shielding film made of a photosensitive resin layer. CONSTITUTION:Residues 203 are removed by dry etching using plasma containing oxygen. A pattern defect generated at an edge portion and residues stuck on picture element electrodes 105 due to incomplete exposure at the time of the development of a black resist 201 by photolithography are removed, and a shielding film 129 having a correct pattern can be completed. A black resist 201 formed on the pattern is used as the resist, a separate metal resist for plasma etching can be omitted, and the process can be avoided from becoming complex.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device, and more particularly to a method of manufacturing a light shielding film portion thereof.

[0002]

2. Description of the Related Art Liquid crystal display devices have been widely used as display devices for televisions, graphic displays and the like, taking advantage of their features such as thinness and low power consumption.

Among them, thin film transistors (TFTs) using polycrystalline silicon, amorphous silicon, or the like.
r; hereinafter abbreviated as TFT) or a metal such as aluminum oxide sandwiched between electrodes formed of a metal thin film
An active matrix type liquid crystal display device using a non-linear element having a non-linear electric resistance such as an M (Metal-Insulator-Metal) element as a switching element is excellent in high-speed response and suitable for high definition display screen. It is attracting attention as a device that realizes high image quality, large size, and color image formation.

As shown in FIGS. 4 and 5, the display element portion of such an active matrix type liquid crystal display device is normally connected to a TFT 403 as a switching active element such as a TFT on a glass substrate 401. Of the active element array substrate 407 on which the pixel electrodes 405 are arranged, and the counter electrode 409 arranged to face the active element array substrate 407 are formed on the glass substrate 411.
3, the liquid crystal layer 415 sandwiched between the substrates 407 and 413, the polarizing plates 417 and 419 attached to the outer surface side of each substrate, and the active element array substrate 407 so as to be orthogonal to each other. The TFT4 provided above
The signal line 421 and the scanning line 423 connected to the signal line 03 make up the main part thereof. Further, in recent years, in order to display the screen in color, R (red) is provided on the counter substrate 411 side.
Color filters 425 having color cells corresponding to the three primary colors of light such as G (green) and B (blue) are often used. Alignment films 427 and 429 are formed so as to cover them.

[0005]

However, in the case of a normal liquid crystal display element used as a transmissive type, the pixel electrode 405 is formed of a transparent conductive film such as ITO, and the pixel electrode 405 and the pixel electrode 405 are opposed thereto. Counter electrode 4
09 and the liquid crystal layer 415 sandwiched between them, a pixel is formed, and only this pixel portion performs a display operation, and the other portion, for example, a so-called non-pixel portion such as between pixels is almost completely absent. It is not operating.

The non-pixel portion such as a gap between pixels is always in a state where unmodulated light is transmitted.
As the display on the screen, light is always leaking,
This means that the background of the image always shows a gradation state to some extent. Therefore, there is a problem that the contrast of the displayed image is significantly lowered.

Therefore, as a measure for preventing such steady leakage of unmodulated light, rubbing treatment is performed so that the angles formed by the rubbing directions of the alignment films 427 and 429 of the two opposing substrates are orthogonal to each other. The polarizing plates 417 and 419 are arranged so that the polarization axes thereof are parallel to each other so that light not modulated by the liquid crystal layer 415 is not transmitted and an operating voltage is applied to the liquid crystal layer 415. There is already known a technique of transmitting light only when light is emitted. According to this technique, non-modulated light is not transmitted in principle.

However, in reality, the transmission of non-modulated light is determined by the accuracy of the alignment of the polarization axes of the two polarizing plates 417 and 419. The polarization axes must be aligned exactly parallel to each other. Even if the polarization axis shift angle is set to 1 degree as a practical alignment accuracy, it is difficult to achieve such alignment accuracy during mass production of liquid crystal display panels.

On the other hand, a rubbing process is performed so that the angles formed by the rubbing directions of the alignment films 427 and 429 of the two opposing substrates are orthogonal to each other to form a TN type liquid crystal cell and the polarizing plates 417 and 419. There is already known a technique of arranging polarization axes so as to be orthogonal to each other and transmitting light only when an operating voltage is applied to the liquid crystal layer 415. According to this technique, the polarizing plates 417, 4
Although the deviation of the polarization axis of 19 causes a slight variation in the light transmittance, it is hardly noticeable in terms of luminosity, has little influence on the contrast of the image, and can be said to have high mass productivity.
However, also in this case, since only the light transmittance of the liquid crystal layer 415 in the pixel portion is variable, in the case of a bright display image, a non-pixel portion such as a gap between pixels is inconspicuous, but in the case of dark display. However, there is a problem in that only the pixel portion becomes dark and the non-pixel portion is left bright and the image becomes unsightly.

Therefore, as a solution to such a problem, a black matrix formed of a metal film having a high light-shielding property such as Cr for blocking transmitted light in a non-pixel portion such as a gap between pixels is used. The technique of forming a so-called light-shielding film on the counter substrate side is already known and has been put into practical use. Such a light-shielding film has an optical density of 2 to
The visible light transmittance of the light-shielding film in this case is required to be about 1 to 0.1%.

However, in the liquid crystal display element using the above-mentioned light shielding film on the counter substrate side, the pixel electrodes arranged on the active element array substrate and the light shielding film arranged on the counter substrate are accurately arranged. There is a problem in that the alignment must be performed with high accuracy, and such alignment is not easy. That is, in many cases, the liquid crystal display element for normal multi-digit display is designed to have a pixel pitch of several 100 μm. For example, in the case of a pitch of 100 μm, in order to obtain a sufficient pixel aperture ratio for good display, The alignment accuracy must be about several μm. However, it is not easy because dimensional errors due to thermal expansion of the glass substrate are involved.

Further, in consideration of the above alignment error and the blocking of the incident light on the liquid crystal display panel from an oblique direction, it is necessary to secure a margin of about 10% for the area of the light blocking film. The value when the area of the electrode is expressed by the aperture ratio is 50% to 60%, whereas the final aperture ratio of the pixel is lowered to 40% to 50%.
This leads to a decrease in the brightness of the displayed image.

Therefore, a technique of disposing the light shielding film on the active element array substrate side is disclosed in, for example, Japanese Patent Laid-Open No. 61-209065.
It is proposed by Japanese Patent Publication No. Such a light-shielding film is made of, for example, a light-shielding film formed of a metal having a high light-shielding property such as Cr, and an organic material such as a photosensitive polymer disclosed in JP-A-61-209065. It can be roughly classified into a black matrix or a light-shielding film formed by dispersing two colors of dyes or pigments having a color tone close to or similar to that of the base material. According to the technique of disposing such a light-shielding film on the active element array substrate side, it is possible to solve the above-mentioned problem of alignment difficulty and the problem of reduction in aperture ratio.

However, when the light-shielding film made of metal is used, there is an advantage that a high light-shielding property can be obtained even if the film thickness is thin, but since the light-shielding film has conductivity, the active element array is used. It is necessary to prevent short circuits with signal lines, scanning lines, pixel electrodes, etc. formed on the substrate, and an interlayer insulating film must be newly formed, which complicates the structure and the manufacturing process. There's a problem. Even if such an interlayer insulating film is formed,
When the interlayer insulating film has, for example, a pinhole defect, there is a problem that a short circuit defect occurs at that portion.

Further, since a metal such as Cr has a high reflectance of light on the surface, there is a problem that the room lighting is reflected on the screen and the display is hard to see.

On the other hand, in the case of a light-shielding film formed by dispersing two or more colors of dyes or pigments having a black color or a color tone close to that or a complementary color relationship to a base material made of an organic material such as a photosensitive polymer, Since the base material is formed of an insulating material such as an organic material, it is possible to avoid the occurrence of a short circuit defect and to manufacture it by a relatively simple photolithography process. is there.

However, in order to obtain the required light-shielding effect with an optical density of about 2 to 3, the film thickness must be increased to about 1.5 to 2 μm. Further, for example, carbon black, which is preferably used as a black pigment, has a certain degree of conductivity, so that if the pigment having such a conductivity is mixed in at a high concentration, the insulation property of the light-shielding film becomes low. Therefore, the pigment can be mixed only up to a certain concentration, so that the film thickness must be further increased to obtain the required optical density.

In a photosensitive resin layer (black resist) such as such a photosensitive polymer, a pigment having a high optical density which interferes with light is present in the base material and the thickness of such a film is large. Therefore, it is difficult to sufficiently reach the deep portion in the thickness direction during exposure. For this reason, a portion that is not completely insolubilized is formed in a portion that originally remains as a pattern during development, and patterning defects such as side etching and pattern chipping or peeling occur, or conversely, development is performed. There is a problem that the residue of the photosensitive resin remains in the portion where the photosensitive resin should originally be completely removed when the removal is performed. Further, there is a problem that photosensitive resins which are eluted one after another during development adhere to the vicinity thereof to form a film and remain as a residue. When the liquid crystal display element is completed, such a residue of the unnecessary portion causes, for example, a defective alignment defect, an uneven brightness defect, or a decrease in transmittance of the pixel portion. Then, such inconvenience in the manufacturing method has been a factor that makes it difficult to realize the black matrix formed on the array substrate side. Even if the development method is changed to develop such a residue or side etching so as to eliminate it, it is inevitable that a 0.01 μm-thick coating film is left entirely, and it is not easy to remove this coating film. is there.

The present invention has been made to solve such a problem, and its purpose is to provide a so-called black light-shielding film formed by using a photosensitive resin layer (black resist) such as a photosensitive polymer. It is an object of the present invention to provide a method for manufacturing a liquid crystal display device, which solves the problem of patterning defects such as pattern chipping, peeling, and residues that occur in a matrix, and has good pattern reproducibility in a black matrix portion. Then, a light-shielding film having an accurate pattern is formed on the active element array substrate side by such a manufacturing method,
It is to realize a liquid crystal display element having a high aperture ratio and a good display quality.

[0020]

In order to solve the above-mentioned problems, a method of manufacturing a liquid crystal display device according to the present invention comprises a plurality of scanning wirings and a plurality of signal wirings formed so as to intersect each other on a substrate and the scanning wirings. And on the main surface of the switching element array substrate in which the switching element formed at each intersection of the signal wiring and connected to the scanning wiring and the signal wiring and the plurality of pixel electrodes connected to the switching element are formed. , A step of forming a photosensitive resin film having a light blocking property, and exposing the photosensitive resin film by photolithography and developing it to etch the photosensitive resin film in the region of the pixel electrode to avoid the pixel electrode substantially. The photosensitive resin film left in the region of the pixel electrode in the step of leaving the photosensitive resin film in the area and the step of exposing and developing the photosensitive resin film by photolithography A step of removing the residual portion by plasma etching using a plasma containing oxygen; a step of arranging a counter substrate on which a counter electrode is formed so as to face the switching element array substrate with a gap; and the switching element array substrate And a step of enclosing and sandwiching the liquid crystal composition between the counter substrate and the counter substrate.

As the light-shielding photosensitive resin film, a so-called black resist in which a photosensitive resin base material contains a black pigment or dye can be used.

In photolithography for exposing and developing the above-mentioned photosensitive resin film, a photomask on which a desired pattern is drawn is used to expose the pattern to the photosensitive resin film and dip it in a developing solution. A so-called resist exposure / development method of dissolving a portion can be used.

In the plasma etching using the plasma containing oxygen, O (oxygen) plasma may be used as an etching gas, or plasma in which O is mixed with Ar (argon) may be used. Alternatively, plasma or the like in which O is mixed with CF ₄ can be used. In addition to this, a material that can exhibit dry etching characteristics suitable for removing the residue generated in the developing step of the photosensitive resin film can be used.

A general manufacturing method may be used for the steps before and after the plasma etching step, for example, the step of forming an active element such as a TFT, the step of forming a counter substrate, and the step of injecting a liquid crystal layer. Needless to say.

[0025]

According to the present invention, a portion of the photosensitive resin film, which is exposed to sufficient light at the time of exposure by photolithography, forms a pattern at the time of development with the developer, and a deep portion of the photosensitive resin film is formed. The portion where light is difficult to reach during exposure and the portion where the photosensitive resin film eluted during development adheres on the pixel electrode are removed by dry etching using the above-described oxygen-containing plasma. Therefore, when developing the photosensitive resin film using photolithography, it is necessary to remove the part that is a pattern defect due to incomplete exposure and the part of the residue attached on the pixel electrode to complete a light-shielding film with an accurate pattern. You can Moreover, at this time, since the light-shielding film obtained by the development is used as the resist for plasma etching, the surface layer part thereof is removed by plasma etching to slightly reduce the thickness, but a separate metal resist for plasma etching, etc. Since it is possible to avoid adding a complicated process for forming the structure, it is possible to prevent the manufacturing process from being complicated because the process consistency in the process is good. Alternatively, if the photosensitive resin film is formed in advance with a thickness increased in consideration of the thickness of the surface layer removed during plasma etching, the surface layer is removed by plasma etching. The disadvantage that the thickness is slightly reduced can be easily eliminated.

In this way, the light-shielding film can be arranged on the active element array substrate side easily by patterning with good pattern reproducibility. The liquid crystal display device obtained as a result can be a liquid crystal display device with a high aperture ratio, excellent contrast characteristics, few electrical short-circuit defects and display defects, and simple manufacture.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method of manufacturing a liquid crystal display device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a plan view showing the structure of a liquid crystal display device manufactured by the manufacturing method of the present invention, and FIG. 2 is a sectional view thereof. Further, FIG. 3 is a view showing the manufacturing method, particularly regarding the steps of the light shielding film portion.

This liquid crystal display device has a glass substrate 101
A TFT element array substrate 107 on which a TFT 103, which is a switching element, and a pixel electrode 105 connected to the TFT 103 are arranged, and a counter electrode 10 arranged to face the TFT element array substrate 107.
9 is a counter substrate 113 formed on a glass substrate 111.
, A liquid crystal layer 115 sandwiched between the substrates 107 and 113, polarizing plates 117 and 119 attached to the outer surface side of each substrate, and the TFT element array substrate 10.
The signal line 121 and the scanning line 123, which are arranged so as to be orthogonal to each other and are connected to the TFT 103, form a main part thereof. In addition, in order to display the screen in color, R (red), G (green), and B are provided on the opposite substrate 111 side.
A color filter 125 having color cells corresponding to the three primary colors of light such as (blue) is formed.

In the case of an ordinary liquid crystal display device used as a transmissive type, the pixel electrode 105 is formed of a transparent conductive film such as ITO, and the pixel electrode 105, the counter electrode 109 facing the pixel electrode 105, and the counter electrode 109 facing the pixel electrode 105. A pixel 127 is formed with the sandwiched liquid crystal layer 115.
The display operation is performed only in the portion of, and the portion outside thereof, for example, the portion between the adjacent pixels 127 is in a state in which almost no operation is performed. A photosensitive resin film having a black dye or pigment in a pattern covering such non-pixel portions and avoiding the pixels 127, so-called black resist, is exposed and developed by photolithography, and residues are removed by plasma etching. A light shielding film 129 is formed.

Then, a SiO _x (silicon oxide) film or Si
Film thickness of 0.2-0.6 μm formed from N _x (silicon nitride) film
Is formed so as to cover the signal line 121 and the like. Then, the TFT element array substrate 107 and the counter substrate 113 are covered with almost the entire surfaces thereof.
Alignment films 133 and 135 are formed, respectively.

In this embodiment, the light shielding film 129 is formed by dispersing a dye or a pigment in a high resistance photosensitive polymer, its thickness is about 1.5 to 2.0 μm, and its visible light transmittance is black matrix. It was set to about 0.3% in consideration of obtaining sufficient light shielding property. Also, this light-shielding film 1
No. 29 was formed of a photosensitive polymer having a high resistance, so that it had a good insulating property.

In this way, the TFT element array substrate 107
Since the light-shielding film 129 is formed on the upper portion, the TFT element array substrate 107 and the counter substrate 113 can be easily aligned with each other. Further, this eliminates the need to take a conventional light-shielding film overlapping the pixel electrode (light-shielding margin) in consideration of the alignment error and the oblique incident light.
The aperture ratio of the pixel electrode 105 corresponding to the light shielding margin can be improved.

Further, since the light shielding film 129 is made of a photosensitive polymer having a high resistance, even if the interlayer insulating film 131 is used.
Even if there is a pinhole defect, it is possible to avoid the occurrence of an interlayer short-circuit defect with the signal line 121 or the like. Moreover, such a light shielding film 129 can be easily manufactured with good pattern reproducibility.

That is, as shown in FIG.
A plurality of signal lines 121 and scanning lines 123 are arranged in a row so as to be orthogonal to each other, and a TFT 103 which is a switching element connected at each intersection is formed, and a pixel electrode 105 connected to the TFT 103 is formed. , The signal line 12
1, the scanning line 123, and the pixel electrode 105 are once covered with SiN ₂ silicon nitride or silicon oxide SiO ₂ and then the pixel electrode 1
Corresponding portions are removed by etching to form the interlayer insulating film 131. (FIG. 3A) Furthermore, a black dye or pigment is used as a photosensitive resin film having a light-shielding property in the base material of the photosensitive polymer so as to cover the main surface of the switching element array substrate including the above. So-called black resist 201 containing 1.5 to 2.0 μm
Spread to a film thickness of the order. It goes without saying that this may be spread by, for example, a spin coating method, or may be spread by another method. (B) Then, by exposing and developing by general photolithography using a photomask, the photosensitive resin film is patterned into a pattern that covers a region substantially avoiding the pixel electrode 105 while providing a slight overlap. , Light shielding film 129
Form a general pattern of. (C) Black resist 201 that is accurately patterned at this time
Is about the total thickness of the black resist 201.
If the optical density is 1.5 μm and the optical density is 2.5, it is about
The thickness is about 1.2 to 1.3 μm, and the remaining 0.2 to 0.3 μm, which is a deeper portion, is not good in pattern reproducibility and remains as a residue 203. This light-shielding film 12
The visible light transmittance of the black resist 201 forming 9 is 0.3 as described above. In such a black resist 201 having a high optical density (high light shielding property), it is difficult for light to reach a deep portion of the film during exposure by photolithography, so that a portion where the resin is not completely solidified occurs. ,Also
This is because the pattern reproducibility of the light-shielding film 129 obtained by development becomes low because the film thickness is made large in order to realize a visible light transmittance of 0.3% and obtain a sufficient light-shielding property. Therefore, in order to eliminate such inconvenience as much as possible, a pressurized developing solution is ejected from a nozzle to perform development. Such a developing method can realize relatively good pattern reproducibility to a deep portion as compared with the stationary or swing developing method. However, it is still difficult to perform more precise patterning for high definition and removal of the residue 203. Further, during development, the resin that is not completely solidified due to lack of light and the resin in which unnecessary portions are dissolved are gradually eluting, and this is the pixel electrode 1
It is unavoidable that it will be deposited on the surface of No. 05 or the like and remain as a residual film of up to about 0.01 μm.

Therefore, the black resist 20 left on the pixel electrodes 105 and the like in the process of forming such a light shielding film 129.
The residue 203 of 0.01 to 0.3 μm of No. 1 is removed by performing plasma etching using plasma containing oxygen using the rough pattern of the light shielding film 129 formed in the photolithography process as a mask. A light shielding film 129 having good pattern reproducibility is formed. (D) In this plasma etching, O (oxygen) plasma may be used as an etching gas, plasma in which O is mixed with Ar (argon), or plasma in which O is mixed with CF ₄ is used. Can be used. In addition to this, an etching gas having a dry etching characteristic suitable for removing the residue 203 generated in the developing process of the photosensitive resin film can be used. The residue 203 could be completely removed by carrying out dry etching for 60 seconds while keeping the pressure at 20 Pa while flowing oxygen of 100 to 200 sccm. However, at this time, since the black resist 201 formed in the general pattern of the light shielding film 129 is used as a mask for plasma etching, the surface layer portion thereof is removed by plasma etching and the thickness is reduced by about the thickness of the residue 203. To do. The thickness of the light-shielding film 129 obtained as a result also includes the residue 203.
It will be reduced by about the thickness. Therefore, in order to eliminate this inconvenience, if the thickness of the black resist 201 is increased in advance in consideration of the thickness to be removed during plasma etching, the surface layer portion is removed by plasma etching. The disadvantage that the thickness is slightly reduced can be easily eliminated. For example, in the present embodiment, the black resist 201 is removed and reduced to about 0.1 μm, so it is desirable to form the black resist 201 thicker by the reduced amount in advance.

After heat curing at 200 ° C. for 60 minutes, a film made of a material such as polyimide or polyvinyl alcohol is formed so as to cover almost the entire main surface of the switching element array substrate including the light shielding film 129. A film is formed, and a rubbing alignment treatment is performed on the surface to form an alignment film 133. On the other hand, on the main surface of the counter substrate 113, color filters 125 in which color cells of three primary colors of R (red), G (green), and B (blue) are alternately arranged at positions facing the respective pixel electrodes. A counter electrode 109 made of a transparent electrode such as ITO is formed on the color filter 125, and an alignment film 135 is formed so as to cover almost the entire main surface of the counter substrate 113 including the counter electrode 109. , This counter substrate 1
13 and the TFT element array substrate 107 are arranged so as to face each other in a substantially parallel manner with a gap, and the periphery is sealed (not shown) and the liquid crystal layer 115 is sealed in the gap to complete the liquid crystal display element. (E) The liquid crystal display device thus obtained was connected to a commonly used drive circuit or the like by a commonly used method and incorporated into a liquid crystal display device, the device was operated to display an image, and the display quality was verified. . As a result, it was confirmed that the screen was bright and had good contrast characteristics, and good display in which uneven brightness was suppressed could be realized. Needless to say, at this time, display defects such as short circuit defects did not occur.

In the above description, one embodiment of the present invention is shown, but in addition to this, the order of the steps before and after the step of forming the light-shielding film 129, such as the order of the step of forming the interlayer insulating film 131, may be appropriately changed. Good. As an example of the order of steps of forming the interlayer insulating film 131, the interlayer insulating film 13 will be described.
The black resist 201, which is a photosensitive resin layer, is developed by photolithography in the state where the insulating film before patterning to be 1 is formed, and then thermally cured to form a light shielding film 129, and the light shielding film 129 is used as a mask. Black resist 20
The residue 203 of No. 1 and the insulating film which is to be the interlayer insulating film 131 may be plasma-etched at one time to form the interlayer insulating film 131 and the residue 203 may be removed at once. Good.

In addition, within a range not departing from the gist of the present invention, the material for forming each part of the liquid crystal display device manufactured by the present invention, the material of the black resist, the exposure method used in the photolithography process, the material of the developing solution, etc. It goes without saying that various changes can be made, such as changing the order of the steps before and after the development of the light-shielding film and the plasma etching step.

[0040]

As is clear from the detailed description above, according to the present invention, a light-shielding film formed using a photosensitive resin layer (black resist) such as a photosensitive polymer is formed in a so-called black matrix. It is possible to provide a method for manufacturing a liquid crystal display device that solves the problem of patterning defects such as pattern chipping, peeling, and residues, and that has good pattern reproducibility in the black matrix portion. With such a manufacturing method, a light-shielding film having an accurate pattern can be formed on the active element array substrate side to realize a liquid crystal display element having a high aperture ratio and good display quality.

[Brief description of drawings]

FIG. 1 is a plan view showing a structure of a liquid crystal display element manufactured by a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of a liquid crystal display element manufactured by the manufacturing method according to the present invention.

FIG. 3 is a diagram showing an embodiment of a method for manufacturing a liquid crystal display element according to the present invention.

FIG. 4 is a plan view showing the structure of a conventional liquid crystal display element.

FIG. 5 is a cross-sectional view showing a structure of a conventional liquid crystal display element.

[Explanation of symbols]

101, 111 ... Glass substrate, 103 ... TFT, 105
... Pixel electrode, 107 ... TFT element array substrate, 109 ...
Counter electrode, 113 ... Counter substrate, 115 ... Liquid crystal layer, 11
7, 119 ... Polarizing plate, 121 ... Signal line, 123 ... Scan line, 125 ... Color filter, 127 ... Pixel, 129 ...
Light-shielding film, 131 ... Interlayer insulating film 133, 135 ... Alignment film

Claims (1)

[Claims] 1. A plurality of scanning wirings and a plurality of signal wirings formed so as to intersect with each other on a substrate, and each scanning wiring and a crossing portion of the signal wirings formed at each intersection and connected to the scanning wirings and the signal wirings. A step of forming a photosensitive resin film having a light shielding property on the main surface of the switching element array substrate on which the switching element and a plurality of pixel electrodes connected to the switching element are formed; Exposing the photosensitive resin film in the area of the pixel electrode by lithography, and leaving the photosensitive resin film in the area substantially avoiding the pixel electrode by etching the photosensitive resin film in the area of the pixel electrode; The residual portion of the photosensitive resin film left in the region of the pixel electrode in the exposing and developing step is removed by plasma etching using plasma containing oxygen. And a step of arranging a counter substrate on which a counter electrode is formed so as to face the switching element array substrate with a gap, and a liquid crystal composition is sealed and sandwiched between the switching element array substrate and the counter substrate. A method of manufacturing a liquid crystal display element, comprising: