阅读说明：本技术 阵列基板及其制备方法 (Array substrate and preparation method thereof ) 是由 钟舒婷 于 2019-10-22 设计创作，主要内容包括：本发明提供一种阵列基板及其制备方法，其制备方法包括制备金属层，在金属层上制备负性光阻层，对负性光阻层进行曝光显影，对金属层进行刻蚀，去除负性光阻层；该制备方法采用负性光阻对金属层进行图案化处理，利用负性光阻见光保留的特性，曝光时在图案内拐角对应位置的负性光阻曝光量足够，显影时图案内拐角对应位置的负性光阻能全部溶于显影液而无残留，保证了后续金属刻蚀过程中金属内拐角处的刻蚀效果，避免了由于光阻曝光不足导致的金属内拐角圆角的问题，从而改善了显示器件暗态漏光的现象，提升了产品的对比度。(The invention provides an array substrate and a preparation method thereof, wherein the preparation method comprises the steps of preparing a metal layer, preparing a negative photoresist layer on the metal layer, exposing and developing the negative photoresist layer, etching the metal layer and removing the negative photoresist layer; the preparation method adopts the negative photoresist to pattern the metal layer, utilizes the characteristic of light retention of the negative photoresist, ensures that the exposure amount of the negative photoresist at the corresponding position of the inner corner of the pattern is enough during exposure, and completely dissolves the negative photoresist at the corresponding position of the inner corner of the pattern in developing into the developing solution without residue, ensures the etching effect of the inner corner of the metal in the subsequent metal etching process, avoids the problem of the fillet of the inner corner of the metal caused by insufficient exposure of the photoresist, thereby improving the dark-state light leakage phenomenon of the display device and improving the contrast ratio of the product.)

1. A preparation method of an array substrate is characterized by comprising the following steps:

preparing a metal layer;

preparing a negative photoresist layer on the metal layer;

exposing and developing the negative photoresist layer;

etching the metal layer;

and removing the negative photoresist layer.

2. The method of claim 1, wherein the step of preparing the metal layer comprises:

depositing a metal layer on the substrate in a magnetron sputtering mode;

and cleaning the substrate by using deionized water.

3. The method according to claim 1, wherein the metal layer comprises at least one of a gate metal layer and a source/drain metal layer.

4. The method according to claim 1, wherein the step of forming a negative photoresist layer on the metal layer comprises:

coating a negative photoresist on the metal layer by adopting a coating process;

drying the negative photoresist in a low-pressure drying mode;

and pre-drying the negative photoresist dried at low pressure.

5. The method according to claim 1, wherein the step of exposing and developing the negative photoresist layer comprises:

exposing the negative photoresist layer by adopting ultraviolet light;

and developing the exposed negative photoresist layer by using a developing solution.

6. The method according to claim 5, wherein the step of exposing the negative photoresist layer with ultraviolet light comprises:

and irradiating the mask plate by adopting ultraviolet light, and irradiating the negative photoresist layer through a light-transmitting area of the mask plate.

7. The method according to claim 5, wherein the step of developing the exposed negative photoresist layer with a developer comprises:

spraying developing solution on the exposed negative photoresist layer in a spraying mode to remove the negative photoresist which is not irradiated by ultraviolet light;

spraying deionized water, and cleaning the developing solution;

removing moisture on the substrate by using an air knife;

and sending the substrate into a hot drying chamber for post-drying treatment.

8. The method according to claim 1, wherein the step of etching the metal layer comprises:

etching the metal which is not covered by the negative photoresist by adopting dry etching or wet etching;

and cleaning the etched substrate by using deionized water.

9. The method according to claim 1, wherein the step of removing the negative photoresist comprises:

and removing the negative photoresist by adopting a stripping process, and cleaning the substrate after the negative photoresist is removed.

10. An array substrate prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of display, in particular to an array substrate and a preparation method thereof.

Background

With the pursuit of higher and higher products, the transmittance and contrast of the display face higher and higher requirements.

However, in the array substrate, since the metal lines in the metal layer have an inner corner rounding phenomenon, the metal is not perpendicular or parallel to the polarizer, and the polarization state of the incident polarized light is changed when the incident polarized light passes through the non-horizontal and non-perpendicular metal corners, light leakage is generated, the contrast is reduced, and the product specification is not up to standard.

Therefore, the problem that the existing array substrate has metal inner corner fillets needs to be solved.

Disclosure of Invention

The invention provides an array substrate and a preparation method thereof, which are used for solving the problem that the existing array substrate has a metal inner corner fillet.

In order to solve the above problems, the technical scheme provided by the invention is as follows:

the invention provides a preparation method of an array substrate, which comprises the following steps:

preparing a metal layer;

preparing a negative photoresist layer on the metal layer;

exposing and developing the negative photoresist layer;

etching the metal layer;

and removing the negative photoresist layer.

In the preparation method of the array substrate provided by the invention, the specific steps of preparing the metal layer comprise:

depositing a metal layer on the substrate in a magnetron sputtering mode;

and cleaning the substrate by using deionized water.

In the preparation method of the array substrate provided by the invention, the metal layer comprises at least one of a grid metal layer and a source drain metal layer.

In the preparation method of the array substrate provided by the invention, the specific step of preparing the negative photoresist layer on the metal layer comprises the following steps:

coating a negative photoresist on the metal layer by adopting a coating process;

drying the negative photoresist in a low-pressure drying mode;

and pre-drying the negative photoresist dried at low pressure.

In the preparation method of the array substrate provided by the invention, the specific step of exposing and developing the negative photoresist layer comprises the following steps:

exposing the negative photoresist layer by adopting ultraviolet light;

and developing the exposed negative photoresist layer by using a developing solution.

In the preparation method of the array substrate provided by the invention, the specific step of exposing the negative photoresist layer by using ultraviolet light comprises the following steps:

and irradiating the mask plate by adopting ultraviolet light, and irradiating the negative photoresist layer through a light-transmitting area of the mask plate.

In the preparation method of the array substrate provided by the invention, the specific step of developing the exposed negative photoresist layer by using a developing solution comprises the following steps:

spraying developing solution on the exposed negative photoresist layer in a spraying mode to remove the negative photoresist which is not irradiated by ultraviolet light;

spraying deionized water, and cleaning the developing solution;

removing moisture on the substrate by using an air knife;

and sending the substrate into a hot drying chamber for post-drying treatment.

In the preparation method of the array substrate provided by the invention, the specific step of etching the metal layer comprises the following steps:

etching the metal which is not covered by the negative photoresist by adopting dry etching or wet etching;

and cleaning the etched substrate by using deionized water.

In the preparation method of the array substrate provided by the invention, the specific step of removing the negative photoresist comprises the following steps:

and removing the negative photoresist by adopting a stripping process, and cleaning the substrate after the negative photoresist is removed.

Meanwhile, the invention provides an array substrate, which is prepared by any one of the preparation methods.

The invention has the beneficial effects that: the invention provides an array substrate and a preparation method thereof, wherein the preparation method comprises the steps of preparing a metal layer, preparing a negative photoresist layer on the metal layer, exposing and developing the negative photoresist layer, etching the metal layer and removing the negative photoresist layer; the preparation method adopts the negative photoresist to pattern the metal layer, utilizes the characteristic of light retention of the negative photoresist, ensures that the exposure amount of the negative photoresist at the corresponding position of the inner corner of the pattern is enough during exposure, and completely dissolves the negative photoresist at the corresponding position of the inner corner of the pattern in developing into the developing solution without residue, ensures the etching effect of the inner corner of the metal in the subsequent metal etching process, avoids the problem of the fillet of the inner corner of the metal caused by insufficient exposure of the photoresist, thereby improving the dark-state light leakage phenomenon of the display device and improving the contrast ratio of the product.

Drawings

In order to illustrate the embodiments or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for a person skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic view of a manufacturing process of an array substrate according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an array substrate according to an embodiment of the present invention.

Fig. 3 is a partially enlarged view of a metal layer of an array substrate according to an embodiment of the present invention.

Detailed Description

While the embodiments and/or examples of the present invention will be described in detail and fully with reference to the specific embodiments thereof, it should be understood that the embodiments and/or examples described below are only a part of the embodiments and/or examples of the present invention and are not intended to limit the scope of the invention. All other embodiments and/or examples, which can be obtained by a person skilled in the art without making any inventive step, based on the embodiments and/or examples of the present invention, belong to the scope of protection of the present invention.

Directional terms used in the present invention, such as [ upper ], [ lower ], [ left ], [ right ], [ front ], [ rear ], [ inner ], [ outer ], [ side ], are only referring to the directions of the attached drawings. Accordingly, the directional terminology is used for the purpose of describing and understanding the invention and is in no way limiting. The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.

In the conventional array substrate manufacturing process, a positive photoresist is generally used to complete the patterning operation, and the positive photoresist has the characteristic of disappearance of visible light and reacts in a developing solution after being irradiated by ultraviolet light. Light irradiates on the glass substrate during exposure and is reflected around an incident point, the positive photoresist layer is influenced by light characteristics at the position corresponding to the inner corner of the pattern, the exposure is insufficient, and the positive photoresist residue at the inner corner during development influences the subsequent etching effect. Therefore, the metal wire in the metal layer has a fillet phenomenon at the inner corner, so that the metal and the polarizer are neither perpendicular nor parallel, and further an electric field is caused to excite dissipated electrons, the polarization state of light penetrating through the lower polarizer is changed, and the problem of dark state light leakage is caused, so that the contrast of the display device is reduced, and even the product does not reach the standard.

In order to solve the above problems, the invention provides an array substrate and a preparation method thereof, which can solve the problem that the existing array substrate has a metal inner corner fillet.

In an embodiment, as shown in fig. 1, the method for manufacturing an array substrate provided by the present invention includes:

s1, preparing a metal layer;

s2, preparing a negative photoresist layer on the metal layer;

s3, exposing and developing the negative photoresist layer;

s4, etching the metal layer;

s5, removing the negative photoresist layer.

The embodiment provides a preparation method of an array substrate, the preparation method adopts a negative photoresist to carry out patterning processing on a metal layer, and utilizes the characteristic of light retention of the negative photoresist, the exposure amount of the negative photoresist at the corresponding position of the inner corner of a pattern is enough during exposure, the negative photoresist at the corresponding position of the inner corner of the pattern can be completely dissolved in a developing solution without residue during development, the etching effect of the inner corner of metal in the subsequent metal etching process is ensured, the problem of the fillet of the inner corner of metal caused by insufficient exposure of the photoresist is avoided, the dark-state light leakage phenomenon of a display device is improved, and the contrast of a product is improved.

In one embodiment, the step of S1 preparing the metal layer includes:

and S11, depositing a metal layer on the substrate in a magnetron sputtering mode.

Magnetron sputtering is one of the physical vapor deposition. Before sputtering begins, the cavity needs to be vacuumized, and the background vacuum degree needs to reach 10^-5Pa magnitude below; after vacuum extraction is finished, introducing sputtering gas, and in sputtering of the metal film, generally using Ar gas as the sputtering gas, wherein the purity of the sputtered Ar gas needs to reach more than 99.99 percent; in the sputtering process, the process conditions of sputtering, such as the magnitude of sputtering power, the temperature of the substrate, the distance from the target surface to the substrate surface, etc., need to be controlled, and the above process parameters can be set according to specific situations, and are not limited herein.

And S12, cleaning the substrate by using deionized water.

After the metal layer is sputtered on the substrate, the substrate needs to be cleaned to remove impurities, and the subsequent processes are continued.

In one embodiment, the metal layer includes at least one of a gate metal layer and a source drain metal layer. The metal layer can be a grid layer, a source drain layer or a grid layer and the source drain layer.

In one embodiment, the step of S2 preparing the negative photoresist layer on the metal layer includes:

and S21, coating a negative photoresist on the metal layer by adopting a coating process.

The coating process generally includes spin coating, blade coating and a combination of spin coating, and fine blade coating, preferably fine blade coating, of a negative photoresist layer on the substrate. The coating speed of the fine blade coating method is required to be controlled to be about 300mm/s, and the thickness of the negative photoresist layer is about 30 nm.

And S22, drying the negative photoresist in a low-pressure drying mode.

In order to prevent the solvent bumping in the subsequent pre-drying process and the defects caused by the flowing of photoresist in the carrying process, a low-pressure drying process is generally performed immediately after the coating is finished, and partial solvent is evaporated by utilizing the principle that the melting point of liquid is reduced under low pressure. The low pressure drying process requires a staged pressure reduction in order to uniformly evaporate the solvent on the surface and in the interior of the photoresist. Depressurization is generally divided into three stages: the first stage is to slowly reduce the pressure so as to avoid bumping of a large amount of solvent; the second stage is rapid pressure reduction, so that the pressure is reduced to a preset air pressure level; the third stage is to maintain the pressure stably so as to ensure that the solvent is fully volatilized; the fourth stage is further decompression, further lowering the melting point of the solvent to further volatilize the solvent; the fifth stage is a rapid recompression process.

And S23, pre-drying the negative photoresist after low-pressure drying.

After the substrate is dried at low pressure, the substrate is transferred to a heat engine table for pre-drying, and the pre-drying comprises three procedures of a hot plate, a cold plate and a precise cold plate. The pre-drying temperature is generally 100-150 ℃, so that the solvent in the photoresist is further evaporated, and the photoresist is solidified and hardened, thereby enhancing the adhesion between the photoresist and the substrate.

In one embodiment, the step of exposing and developing the negative photoresist layer in S3 includes:

and S31, exposing the negative photoresist layer by ultraviolet light.

Specifically, ultraviolet light is adopted to irradiate the mask plate, and the negative photoresist layer is irradiated through the light-transmitting area of the mask plate. The pattern of the light-transmitting area of the mask is the patterned pattern of the metal layer, and the ultraviolet light can fully irradiate the position of the inner corner of the pattern of the light-transmitting area and penetrate through the inner corner, so that the negative photoresist at the corresponding position of the inner corner of the pattern can obtain enough exposure.

And S32, developing the negative photoresist layer after exposure by a developer.

Development is the process of reacting the photoresist with an alkaline developer. Commonly used alkaline developers include strong base systems typified by KOH (K is an alkali metal) and weak base systems typified by a bicarbonate salt.

The negative photoresist mainly comprises a solvent, a pigment, a dispersing agent, a monomer, a polymer and a photoinitiator, and has the characteristic of light retention. In an exposed area, the negative photoresist is irradiated by ultraviolet light to generate a chemical reaction, and a photoinitiator in the negative photoresist is decomposed to generate free radicals, so that double bonds of the monomer and the polymer are opened to generate a cross-linking and bridging reaction to form a network, and a film structure which is not easy to dissolve in an alkaline developing solution is generated; in the unexposed area, because the polymer resin contains carboxyl acid groups and does not generate cross-linking and bridging reaction, the polymer resin is easy to react and dissolve with an alkaline developing solution; therefore, the unexposed part of the negative photoresist layer reacts with the developer rapidly to dissolve, and the exposed part remains.

In one embodiment, the step of developing the exposed negative photoresist layer with a developer comprises:

s321, spraying a developing solution on the exposed negative photoresist layer in a spraying manner to remove the negative photoresist which is not irradiated by the ultraviolet light;

s322, spraying deionized water, and cleaning the developing solution;

s323, removing moisture on the substrate by using an air knife;

and S324, sending the substrate into a hot drying chamber, and performing post-drying treatment, wherein the post-drying mainly has the functions of removing residual moisture and enabling the photoresist to become firm and to be in close contact with the substrate.

In one embodiment, the step of etching the metal layer in S4 includes:

and S41, etching the metal which is not covered by the negative photoresist by adopting dry etching or wet etching.

In the manufacturing process of the array substrate, wet etching is usually used to pattern the conductive metal layer. In wet etching, the components of the etched film are different, the etching liquid medicine is correspondingly changed, and the chemical reaction is also different. The corresponding etching solution can be selected according to the specific material of the metal layer to be etched, which is not limited herein.

And S42, cleaning the etched substrate by using deionized water.

In one embodiment, the step of removing the negative photoresist in S5 includes:

and S51, removing the residual negative photoresist by adopting a stripping process.

The photoresist stripping process is a process of removing the photoresist on the substrate after the etching process by using a dry process or a wet process, and includes dry stripping and wet stripping, wherein the wet stripping is commonly used. A commonly used stripping solution is a colorless, transparent, but pungent liquid mixed at a ratio of DMSO to MEA of 7:3 (mass ratio). The chemical formula of DMSO is (CH)₃)₂SO, whose main function is to swell the photoresist, and MEA has a chemical formula of OH (CH)₂)₂NH, which is mainly used to wet the interface between the photoresist and the substrate, so that the photoresist is stripped and dissolved.

And S52, cleaning the substrate after the negative photoresist is removed.

Meanwhile, as shown in fig. 2, an embodiment of the present invention further provides an array substrate, and the array substrate is prepared by the method for preparing an array substrate according to the embodiment of the present invention.

The embodiment of the invention provides an array substrate, which comprises a metal layer, wherein the metal layer is obtained by patterning negative photoresist, and the inner corner of a metal wire in the metal layer is a right angle, so that the problem of a metal inner corner fillet caused by insufficient exposure of the photoresist is avoided, the dark-state light leakage phenomenon of a display device is improved, and the contrast of a product is improved.

In one embodiment, as shown in fig. 2, the array substrate 10 includes:

the substrate 101 is typically a glass substrate or a flexible substrate made of a flexible material.

The barrier layer 102 is formed on the substrate 101 and used for blocking water and oxygen from entering the display panel, so that the service life of the display panel is prevented from being reduced; and preventing diffusion of impurity particles into the thin film transistor, avoiding reduction of leakage current. The barrier layer 102 is generally made of silicon nitride (SiNx) material, which has a strong ion-blocking capability and a good water-oxygen-blocking capability.

The buffer layer 103 is formed on the barrier layer 102, and is also used for blocking water, oxygen and impurity particles from entering the thin film transistor, the buffer layer 103 is generally made of silicon oxide (SiOx) material, and the interface wettability of silicon oxide and polysilicon is better, and the buffer layer can be better used as a substrate material for forming the active layer 104.

And the active layer 104 is formed on the buffer layer 103, and is patterned to form an active region which is doped to form a channel region and a doped region.

And a gate insulating layer 105 covering the buffer layer 103 and the active layer 104. The gate insulating layer 105 is a stacked structure of silicon nitride/silicon oxide, the silicon nitride has high breakdown voltage and can be used as a good gate insulating material, and the silicon oxide and the polysilicon surface have good grain boundary matching, stress matching and good step coverage.

A gate electrode layer 106 formed on the gate insulating layer 105 and patterned with a gate electrode and a first signal line.

And an interlayer insulating layer 107 covering the gate insulating layer 105 and the gate electrode layer 106.

And a source drain layer 108 formed on the interlayer insulating layer 107 and patterned with a source, a drain, and a second signal line.

And a passivation layer 109 covering the interlayer insulating layer 108 and the source/drain layer 107.

In one embodiment, the array substrate includes at least two metal layers, the metal layers are patterned to form metal lines, there is at least one metal layer, and the inner corners of the metal lines 110 are right-angled, as shown in fig. 3.

In one embodiment, the metal layer includes a gate metal layer and a source drain metal layer, and the inner corner of the metal line is a right angle in the gate metal layer. The gate metal layer is prepared by the preparation method of the array substrate in the embodiment, and the inner corner of the metal pattern formed by patterning the metal layer in the gate layer is a right angle. The polarized light at the inner corner is prevented from changing due to the inner corner round angle, so that the phenomenon of dark state light leakage of the display panel is relieved, and the contrast of a product is improved.

In one embodiment, the gate metal layer is arranged in a single layer, that is, the array substrate is in a single-gate structure, so that the arrangement of one metal layer is reduced, and a positive effect on the thinning of the display panel is achieved.

In another embodiment, the gate metal layers include a first gate metal layer and a second gate metal layer, that is, the array substrate has a double-gate structure. The first grid metal layer is patterned to form a grid, a first scanning signal line and a first electrode plate; the second grid metal layer is patterned to form a second scanning signal line and a second electrode plate, and the second electrode plate and the first electrode plate are arranged oppositely.

In this embodiment, the inner corner of the metal line in the first gate metal layer may be a right angle, that is, the first gate metal layer is prepared by the preparation method of the array substrate described above, and the second gate metal layer is prepared by a conventional method; or the inner corner of the metal line in the second gate metal layer is a right angle, that is, the second gate metal layer is prepared by the preparation method of the array substrate, and the first gate metal layer is prepared by the conventional method; the inner corners of the metal lines in the first gate metal layer and the second gate metal layer are both right angles, that is, the first gate metal layer and the second gate metal layer are both prepared by the preparation method of the array substrate.

In another embodiment, the metal layer includes a gate metal layer and a source drain metal layer, and the inner corner of the metal line is a right angle in the source drain metal layer. The source and drain metal layer is prepared by the preparation method of the array substrate in the embodiment, and the inner corner of the metal pattern formed by patterning the metal layer in the source and drain metal layer is a right angle. The polarized light at the inner corner is prevented from changing due to the inner corner round angle, so that the phenomenon of dark state light leakage of the display panel is relieved, and the contrast of a product is improved.

In another embodiment, the metal layer includes a gate metal layer and a source/drain metal layer, and the inner corners of the metal lines in the source/drain metal layer and the gate metal layer are both right angles, that is, the source/drain metal layer and the gate metal layer are both prepared by the method for preparing the array substrate described in the foregoing embodiment. The metal inner corners in the grid metal layer and the source drain metal layer in the array substrate are set to be right angles, the problem of corner fillets in the metal layers is further solved, the polarization state of polarized light at the corners in the metal layers is prevented from being changed, the phenomenon of dark state light leakage of the display panel is relieved, and the contrast ratio of a product is improved.

According to the above embodiments:

the embodiment of the invention provides an array substrate and a preparation method thereof, wherein the preparation method comprises the steps of preparing a metal layer, preparing a negative photoresist layer on the metal layer, exposing and developing the negative photoresist layer, etching the metal layer and removing the negative photoresist layer; the preparation method adopts the negative photoresist to pattern the metal layer, utilizes the characteristic of light retention of the negative photoresist, ensures that the exposure amount of the negative photoresist at the corresponding position of the inner corner of the pattern is enough during exposure, and completely dissolves the negative photoresist at the corresponding position of the inner corner of the pattern in developing into the developing solution without residue, ensures the etching effect of the inner corner of the metal in the subsequent metal etching process, avoids the problem of the fillet of the inner corner of the metal caused by insufficient exposure of the photoresist, thereby improving the dark-state light leakage phenomenon of the display device and improving the contrast ratio of the product.

In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.