WO2015169081A1

WO2015169081A1 - Ito film etching method and array substrate comprising electrode layers formed by same

Info

Publication number: WO2015169081A1
Application number: PCT/CN2014/091708
Authority: WO
Inventors: 卜倩倩; 郭炜; 任庆荣; 王路; 刘英伟
Original assignee: 京东方科技集团股份有限公司
Priority date: 2014-05-05
Filing date: 2014-11-19
Publication date: 2015-11-12
Also published as: CN103972075A

Abstract

An ITO film etching method and an array substrate comprising electrode layers manufactured by same, which solve the problem that etching is not complete and the etching speed is low during etching of ITO patterning in existing array substrate manufacturing, improve the etching effect and practicality of ITO patterning of a display panel, increase the etching rate, and reduce the etching cost. The ITO film etching method comprises: forming an indium tin oxide (ITO) film (2) on a substrate (1); forming a photoresist layer (3) on the ITO film (2); disposing a mask plate (4) above the photoresist layer (3), part of the photoresist layer (3) being not covered by the mask plate (3); removing photoresist in the photoresist layer (3) not covered by the mask plate (4); etching off the part of the ITO film (2) not covered by the remaining photoresist layer by a wet etching process; and etching off the part, left after the etching by the wet etching process, in the part of the ITO film (2) not covered by the remaining photoresist layer by a dry etching process. The ITO film etching method can be applied to manufacturing of display panels.

Description

ITO film layer etching method and array substrate including electrode layer formed using the method

Technical field

The present invention relates to an ITO film layer etching method and an array substrate including the electrode layer formed using the method.

Background technique

With the rapid development of display device technologies such as Thin Film Transistor Liquid Crystal Display (TFT-LCD), the demand for high-light transmittance and ultra-low-resistance transparent electrodes is increasing. At present, the most commonly used transparent conductive oxide (TCO) thin film material in flat display is indium tin oxide (ITO), which is an N-type semiconductor material in terms of conductivity and transparency. The aspect has extremely superior performance. When such materials are used in display devices, their patterning is a very critical step.

An ITO patterning method used in a known technical solution is a wet chemical etching method. However, the wet chemical etching method has an etching film thickness greater than

When ITO is used, it is often etched and the image may be short-circuited. If the etching time is increased and the etching concentration is increased to solve the problem of unclean etching in wet etching, the service life of the etching equipment will be affected. At the same time, the etching time may be uneven or engraved. The problem of excessive eclipse affects the performance of the product. Another possible solution is to use plasma dry etching. However, the plasma dry etching method requires a large etching cost and a slow etching rate in practical applications.

Summary of the invention

At least one embodiment of the present invention provides an etching method of an ITO film layer, the method comprising:

Forming an ITO film layer on the substrate;

Forming a photoresist layer on the ITO film layer;

Providing a mask above the photoresist layer, the mask not completely covering the photoresist layer;

Removing a photoresist in the photoresist layer that is not covered by the mask;

Etching the portion of the ITO film layer that is not covered by the remaining photoresist layer in the ITO film layer by a wet etching process;

Etching the portion of the residual ITO film layer etched by the wet etching process in the portion of the ITO film layer not covered by the remaining photoresist layer in the ITO film layer by a dry etching process .

In one example, the method further includes:

The photoresist remaining in the photoresist layer after being etched by the wet etching process and the dry etching process is removed.

In one example, the method further includes:

Before or during the dry etching process, the etching conditions of the dry etching process are set according to the etching apparatus used for the dry etching.

In one example, the etching apparatus is an RIE apparatus, and the etching conditions include etching power, type of gas used, and pressure.

In one example, the etching device is a plasma etching device.

In one example, the thickness of the ITO film layer in the step of forming an ITO film layer on the substrate is greater than the thickness of the ITO pattern layer to be formed.

In one example, the thickness of the ITO film layer is greater in the step of forming an ITO film layer on the substrate

In one example, the photoresist layer has a thickness of 1.0 to 1.2 μm in the step of forming a photoresist layer on the ITO film layer.

In one example, the step of forming a photoresist layer on the ITO film layer further includes pre-baking and post-baking.

In one example, the method further includes:

When the ITO film layer is etched by a wet etching process, the concentration of the etching solution is set to be less than or equal to a preset concentration, and the predetermined concentration is sulfuric acid: nitric acid: additive = 8:4.5:2 ( Wt%).

In one example, the concentration of the etchant is set such that it is 95% of the preset concentration.

In one example, the method further includes:

When the ITO film layer is etched by a wet etching process, an etching time is set to be less than a preset time, and the preset time is 120 s.

In one example, the etch time is set to be 117 s.

At least one embodiment of the present invention also provides an array substrate, the array substrate comprising:

Substrate

The ITO pixel electrode layer covering the substrate is formed by using an ITO film layer etching method provided by the embodiment of the present invention.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic flow chart of an etching method according to an embodiment of the present invention;

2 is a schematic flow chart of an etching method according to an embodiment of the present invention;

3 is a schematic structural view of an ITO film layer formed on a substrate in an etching method according to an embodiment of the present invention;

4 is a schematic structural view of a photoresist layer formed on an ITO film layer in an etching method according to an embodiment of the present invention;

5 is a schematic structural view of a photoresist layer patterned by using a mask in an etching method according to an embodiment of the present invention;

6 is a schematic structural view of a etching method according to an embodiment of the present invention after a wet etching process;

FIG. 7 is a schematic structural view of an etching method according to an embodiment of the present invention after a dry etching process;

FIG. 8 is a schematic structural diagram of removing a residual photoresist on a substrate in an etching method according to an embodiment of the present invention.

Reference numerals: 1-substrate; 2-ITO film layer; 3-photoresist layer; 4-mask plate; 21-residual ITO.

detailed description

The technical solution in the embodiment of the present disclosure will be described below with reference to the accompanying drawings in the embodiments of the present disclosure. It is clear that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without departing from the inventive scope are the scope of the disclosure.

Unless otherwise defined, technical terms or scientific terms used herein shall be taken to mean the ordinary meaning of the ordinary skill in the art to which the invention pertains. The words "first", "second" and similar terms used in the specification and claims of the present disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the words "a" or "an" and the like do not denote a quantity limitation, but mean that there is at least one. The words "connected" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to indicate the relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship is also changed accordingly.

The etching method of the ITO film layer provided by the embodiment of the invention is as shown in FIG. 1 , and the method comprises the following steps:

101, forming an ITO film layer on the substrate;

102, forming a photoresist layer on the ITO film layer;

103. A mask is disposed over the photoresist layer, wherein the mask does not completely cover the photoresist layer;

104. Removing the photoresist in the photoresist layer that is not covered by the mask;

105, using a wet etching process to etch away portions of the ITO film layer that are not covered by the remaining photoresist layer;

106. The residual ITO film layer portion etched by the wet etching process in the portion of the ITO film layer not covered by the remaining photoresist layer in the ITO film layer is etched by a dry etching process.

The ITO film layer etching method provided by the embodiment of the present invention adopts a combination of a wet etching process and a dry etching process, and solves the etching caused by the excessive ITO film thickness in the conventional ITO pattern etching. The problem of uncleanness and slow etching speed enhances the etching effect of ITO patterning and practicality in practical applications, improves the etching rate, and reduces the etching cost.

An ITO film layer etching method provided by an embodiment of the present invention is shown in FIG. 2, and the method includes the following steps:

201. Forming an indium tin oxide (ITO) film layer on the substrate.

An example of the step 201 is shown in FIG. 3, which shows a process of forming the ITO film layer 2 on the substrate 1. For example, the ITO film layer 2 covering the substrate 1 may be formed by magnetron sputtering on a substrate 1 such as a glass substrate or a quartz substrate prepared in advance by a vacuum coater. Of course, the manner of forming the ITO film layer 2 and the type of the substrate are merely exemplified herein, and the present invention is not limited thereto, and a suitable substrate and an appropriate manner may be selected according to a specific implementation environment in practical applications. For example, the substrate may be a substrate of a display panel, a substrate of a color filter, a glass substrate, or a flexible substrate.

In this embodiment, the thickness of the ITO film layer 2 on the substrate is greater than a predetermined film thickness. The predetermined film thickness here may be the film thickness of the ITO pattern layer to be formed. For example, for the ITO pixel electrode layer, the predetermined film thickness of the ITO film layer 2 may be

Of course, the numerical value of the preset film thickness is merely exemplified herein. The present invention is not limited thereto, and a suitable value may be selected according to the actual needs and application scenarios of the ITO pattern layer to be formed in a specific application.

202. Forming a photoresist layer on the ITO film layer.

An example of the step 202 is shown in FIG. 4, which shows a process of forming the photoresist layer 3 on the ITO film layer 2. For example, a photosensitive photoresist covering the ITO film layer 2 may be formed on the ITO film layer 2 by coating, thereby forming the photoresist layer 3.

In this example, for example, the photosensitive photoresist may be a positive photoresist, which may be uniformly formed on the ITO film layer 2 by, for example, spin coating, but the invention is not limited thereto, but may This is accomplished by any other suitable coating means known in the art, such as roll coating, pull coating, and spray dynamic coating.

The film thickness of the photosensitive photoresist needs to balance the protection and etching time of the ITO. In this example, the thickness of the photoresist film layer may be 1.0-1.2 μm. For example, for ITO preset film thickness is greater than

And less than

In the case, the thickness of the photoresist film can be selected to be 1.1 μm.

In this embodiment, the photoresist coating process requires pre-baking and post-baking to evaporate the solvent in the photosensitive photoresist while increasing the adhesion of the ITO film layer 2 to the photosensitive photoresist. . For example, pre-baking is performed for 150 s at a temperature of 110 ° C using an exposure machine, and post-baking is performed at a temperature of 130 ° C for 170 s, but the present invention is not limited thereto.

203. A mask is disposed over the photoresist layer, the mask not completely covering the photoresist layer.

In one example, the mask 4 is not autonomously carried in the device and is required to be installed in the device after being designed. In another example, the mask 4 is autonomously carried in the device. Does not make contact with the photoresist layer 3.

204. Removing the photoresist in the photoresist layer that is not covered by the mask.

For example, as shown in FIG. 5 is a schematic view after patterning the photoresist layer 3 using the mask 4, in this example, using the mask 4 to pattern photosensitive lithography by patterning processes such as exposure, development, and etching. The glue layer 3 is formed to form a patterned photosensitive layer. This process is known in the art and will not be described in detail herein.

205. Etching the portion of the ITO film layer that is not covered by the remaining photoresist layer in the ITO film layer by a wet etching process.

For example, as shown in FIG. 6, after the mask 4 is removed, the pattern of the photoresist layer 3 is removed by etching away a portion of the ITO film layer 2 that is not covered by the photoresist layer 3 by a wet etching process. The pattern formed by the pattern of the photosensitive layer is transferred to the ITO film layer 2. As can be seen from FIG. 6, a portion of ITO 21 remains in the ITO film layer 2 after etching by a wet etching process.

In one example, the etching mode of the wet etching is a shower mode, but the invention is not limited thereto, and may be, for example, a soaking mode.

In one example, when the ITO film layer 2 is etched by a wet etching process, the concentration of the wet etching etchant may be set to be less than or equal to the usual concentration of the prior art. For example, in the existing spray etching process, the etching temperature is generally 45 ° C, the etching time is generally 120 s, and the etching solution concentration is generally sulfuric acid: nitric acid: additive = 8: 4.5: 2 (Wt% The etching solution concentration in the wet etching of the ITO etching method of the embodiment of the present invention may be about 5% smaller than the above concentration (that is, about 95% of the above concentration), and the etching time may be reduced compared with the above time. About 3 seconds (that is, about 117s), in order to control the critical dimension of the etching, the temperature of the etching apparatus can be extended by the above temperature value (that is, 45 ° C); however, the invention is not limited thereto.

206. Etching the portion of the residual ITO film layer etched by the wet etching process in the portion of the ITO film layer not covered by the remaining photoresist layer in the ITO film layer by a dry etching process .

For example, as shown in FIG. 7, the structure of the ITO portion 21 remaining after etching by the wet etching process in the ITO film layer 2 is completely etched by a dry etching process.

In this embodiment, an etching device used for dry etching is also required to make the etching condition satisfy the preset condition.

For example, the dry etching apparatus usable in this embodiment includes: Inductively Coupled Plasma (ICP) equipment, plasma etching (PE) equipment, and reactive ion etching (Reactive Ion Etching). , referred to as RIE) equipment. For example, when performing dry etching using the RIE apparatus, examples of preset conditions that can be set include: an etching power of 100-1000 w and a pressure of 10-400 mTorror, and the gas used may include one or any of the following Combination of terms: He, CHF ₃ , Cl ₂ , Ar, C ₂ H ₄ .

In one example, the etching conditions for dry etching using the RIE apparatus include: a power of 1000 W, a pressure of 40 mtorr, and a gas flow ratio of He/Cl ₂ = 100/300 sccm.

In another example, the etching conditions for dry etching using the RIE apparatus include: a power of 1000 W, a pressure of 40 mtorr, and a gas flow ratio of He/Cl ₂ = 50/300 sccm. At this time, the etching rates of the corresponding amorphous ITOs are respectively

The etching uniformity was 8.5% and 6.8%, respectively.

In yet another example, the etching conditions for dry etching using the RIE apparatus include: a power of 1000 W, a pressure of 40 mtorr, and a gas flow ratio of He/Cl ₂ = 100/300 sccm. At this time, the etching rate of the corresponding polycrystalline ITO is

The etching uniformity was 11.1%.

For another example, when dry etching is performed using a plasma etching apparatus, the plasma gas can interact with the photoresist to make the subsequent stripping of the photoresist faster, easier, and more thorough.

It should be noted that the etching conditions using dry etching are merely exemplified herein. The present invention is not limited thereto, and suitable etching conditions may be selected as preset conditions according to a specific operating environment in practical applications.

It should be noted that the process of setting the etching conditions of the dry etching apparatus may be performed at any step before step 206, or may be performed simultaneously with step 206. The specific implementation sequence can be selected according to the needs of the actual operating environment.

207. Remove the photoresist remaining in the photoresist layer after etching by a wet etching process and a dry etching process.

For example, as shown in FIG. 8, the photosensitive photoresist layer remaining on the substrate can be removed with a stripping solution.

In this embodiment, the duration of the wet etching may be determined according to the remaining thickness of the ITO film thickness (ie, the desired residual film thickness after the wet etching) and the selected wet etching rate, for example, It is generally expected that the thickness of the remaining ITO film after wet etching is less than 5% of the thickness of the original ITO film; the duration of the dry etching can be based on the actual remaining ITO film thickness and dry method after wet etching in the ITO film layer. The etch rate of the etch is calculated. Corresponding calculation method It is known in the art and will not be described in detail herein.

In the ITO etching method provided by the embodiment of the present invention, the unnecessary ITO in the patterned ITO film layer to be obtained is first etched by a wet etching process, and then etched through the wet process by a dry etching process. After etching, all the ITO remaining in the corresponding position finally forms the desired patterned ITO film layer, thereby greatly improving the quality of the product and avoiding the uniform etching uniformity of the single wet etching, especially It is a problem that the critical dimension deviation control is difficult. By using the etching method provided by the embodiment of the invention, the desired patterned ITO film layer can be conveniently obtained, and the use time of the device can be improved. Embodiments of the present invention also provide an array substrate including: a substrate and an ITO pixel electrode layer covering the substrate. The ITO pixel electrode layer is formed by an ITO film layer etching process which is combined with a wet etching process and a dry etching process provided by at least one embodiment of the present invention. Therefore, the preparation method and corresponding structure and advantages of the ITO pixel electrode layer in the array substrate can be referred to the descriptions in the above with reference to FIG. 1-7, and no further details are provided herein.

In the array substrate provided by the embodiment of the present invention, the ITO pixel electrode layer is formed by a combination of a wet etching process and a dry etching process, which solves the problem of performing ITO in the existing array substrate fabrication scheme. In the pattern etching, the etch film is not clean and the etching speed is slow due to the excessive thickness of the ITO film, which enhances the etching effect of the ITO patterning of the display panel and the practicability in practical applications, and improves the engraving. The etch rate also reduces the etching cost, which in turn increases production efficiency.

The above embodiments are merely illustrative of the disclosure, and are not intended to limit the scope of the disclosure, and various changes and modifications can be made without departing from the spirit and scope of the disclosure. Equivalent technical solutions are also within the scope of the disclosure, and the scope of patent protection of the disclosure should be defined by the claims.

The present application claims priority to Chinese Patent Application No. 201410187181.3, filed on May 5, 2014, which is hereby incorporated by reference.

Claims

An ITO film layer etching method, comprising:

Forming an indium tin oxide (ITO) film layer on the substrate;

Forming a photoresist layer on the ITO film layer;

Providing a mask above the photoresist layer, the mask not completely covering the photoresist layer;

Removing a photoresist in the photoresist layer that is not covered by the mask;

Etching the portion of the ITO film layer that is not covered by the remaining photoresist layer in the ITO film layer by a wet etching process;

A portion of the ITO film layer in the portion of the ITO film layer that is not covered by the remaining photoresist layer is etched by the wet etching process in a portion of the ITO film layer by a dry etching process.
The method of claim 1 further comprising:

The photoresist remaining in the photoresist layer after etching by the wet etching process and the dry etching process is removed.
The method of claim 1 or 2, further comprising:

Before or during the dry etching process, the etching conditions of the dry etching process are set according to the etching apparatus used for the dry etching.
The method of claim 3 wherein said etching device is a RIE device and said predetermined conditions include etching power, type of gas used, and pressure.
The method of claim 3 wherein said etching device is a plasma etching device.
A method according to any one of claims 1 to 5, wherein

The thickness of the ITO film layer on the substrate is greater than the thickness of the ITO pattern layer to be formed.
The method according to claim 6, wherein the step of forming the ITO film layer on the substrate has a thickness greater than that of the ITO film layer
The method according to any one of claims 1 to 7, wherein the photoresist layer has a thickness of 1.0 to 1.2 μm in the step of forming a photoresist layer on the ITO film layer.
The method according to any one of claims 1 to 8, wherein the ITO film The step of forming a photoresist layer on the layer further includes pre-baking and post-baking.
The method of any of claims 1-9, further comprising:

When the ITO film layer is etched by a wet etching process, the concentration of the etching solution is set to be less than or equal to a preset concentration, and the predetermined concentration is sulfuric acid: nitric acid: additive = 8:4.5:2 ( Wt%).
The method according to claim 10, wherein the concentration of the etching liquid is set to be 95% of the predetermined concentration.
The method of any of claims 1-11, further comprising:

When the ITO film layer is etched by a wet etching process, an etching time is set to be less than a preset time, and the preset time is 120 s.
The method of claim 12, wherein the etching time is set to be 117 s.
An array substrate comprising:

Substrate

An ITO pixel electrode layer covering the substrate, the ITO pixel electrode layer being formed by the etching method according to any one of claims 1-13.