阅读说明：本技术 基片的刻蚀方法和薄膜晶体管 (Substrate etching method and thin film transistor ) 是由 刘海龙 朱瑞苹 郑浩田 于 2020-12-03 设计创作，主要内容包括：本发明公开一种基片的刻蚀方法和薄膜晶体管,基片的刻蚀方法包括：在基片的金属银层上形成具有预定图案的掩膜层；向刻蚀腔内通入刻蚀气体,通过激发所述刻蚀气体为第一等离子体,刻蚀所述掩膜层和所述金属银层,以在所述金属银层上形成刻蚀沟槽,其中,所述第一等离子体包括甲基离子和氢离子中的至少一者。采用上述刻蚀方法可以解决目前采用氧离子对金属银进行刻蚀的过程中,产生的氧化银会粘附且堆积在刻蚀孔的内壁,导致刻蚀孔被堵塞,进而刻蚀失败率较高的问题。(The invention discloses a substrate etching method and a thin film transistor, wherein the substrate etching method comprises the following steps: forming a mask layer with a preset pattern on a metal silver layer of a substrate; and introducing etching gas into the etching cavity, and etching the mask layer and the metal silver layer by exciting the etching gas as first plasma to form an etching groove on the metal silver layer, wherein the first plasma comprises at least one of methyl ions and hydrogen ions. By adopting the etching method, the problems that the generated silver oxide can be adhered and accumulated on the inner wall of the etching hole to cause the blockage of the etching hole and the higher etching failure rate in the process of etching the metal silver by adopting oxygen ions at present can be solved.)

1. A method of etching a substrate, comprising:

forming a mask layer with a preset pattern on a metal silver layer of a substrate;

and introducing etching gas into the etching cavity, and etching the mask layer and the metal silver layer by exciting the etching gas as first plasma to form an etching groove on the metal silver layer, wherein the first plasma comprises at least one of methyl ions and hydrogen ions.

2. The etching method of claim 1, wherein the introducing of the etching gas into the etching chamber, the exciting of the etching gas into the first plasma, and the etching of the mask layer and the metallic silver layer to form the etching trench on the metallic silver layer further comprise:

and introducing bombardment gas into the etching cavity, and exciting the bombardment gas into second plasma for destroying the metal bond of the metal silver layer.

3. The etching method of claim 2, wherein the bombardment gas comprises at least one of argon, helium, and nitrogen.

4. The etching method according to claim 1, wherein the first plasma further comprises at least one of argon ions, helium ions, and nitrogen ions.

5. The etching method according to any one of claims 1 to 4, wherein when the mask layer and the metallic silver layer are etched in the etching chamber, the frequencies of the upper RF power supply and the lower RF power supply are both 13.56MHz, the power of the upper RF power supply is 600-1500W, the power of the lower RF power supply is 100-500W, the process pressure is 3-20 mT, the temperature is 20-50 ℃, and the current ratio is 0.2-0.8.

6. The etching method according to any one of claims 1 to 4, wherein the mask layer comprises a photoresist mask layer and an antireflective mask layer, and the forming of the mask layer with the predetermined pattern on the metallic silver layer of the substrate comprises:

covering the substrate with a metal silver layer;

covering an anti-reflection mask layer on the metal silver layer;

covering a photoresist mask layer on the anti-reflection mask layer;

and exposing the photoresist mask layer and the anti-reflection mask layer to form a mask layer with a preset pattern.

7. The etching method of claim 6, wherein the introducing of the etching gas into the etching chamber, and the exciting of the etching gas into the first plasma etches the mask layer and the metallic silver layer to form an etched trench in the metallic silver layer further comprises:

and cleaning the residual mask layer on the substrate.

8. The etching method according to claim 7, wherein after the cleaning of the mask layer remaining on the substrate, further comprising:

and removing the silver-containing and/or methyl-ion-containing etching byproducts attached to the substrate.

9. The etching method according to claim 8, wherein the steps of cleaning the mask layer remaining on the substrate and removing the silver-containing and/or methyl-ion-containing etching byproducts attached to the substrate further comprise:

reducing the temperature of the substrate.

10. A thin film transistor manufactured based on the etching method according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of semiconductor processing, in particular to a substrate etching method and a thin film transistor.

Background

Metallic silver is widely used in many fields due to its good properties, such as in displays, and silver can be used to form thin film transistors. At present, the metal silver is usually etched by using oxygen ions, but because the boiling point of the silver oxide formed by etching is relatively high, in the process of etching the metal silver layer 910 by using such an etching method, as shown in fig. 1, the generated silver oxide 930 may adhere and accumulate on the inner wall of the etching hole, so that the etching hole is blocked, and further, the etching failure rate is high.

Disclosure of Invention

The invention discloses a substrate etching method and a thin film transistor, and aims to solve the problems that silver oxide generated in the process of etching metal silver by adopting oxygen ions adheres to and is accumulated on the inner wall of an etching hole, so that the etching hole is blocked, and the etching failure rate is high.

In order to solve the problems, the invention adopts the following technical scheme:

in a first aspect, the invention discloses a method for etching a substrate, comprising:

forming a mask layer with a preset pattern on a metal silver layer of a substrate;

and introducing etching gas into the etching cavity, and etching the mask layer and the metal silver layer by exciting the etching gas as first plasma to form an etching groove on the metal silver layer, wherein the first plasma comprises at least one of methyl ions and hydrogen ions.

In a second aspect, the invention discloses a thin film transistor, which is manufactured based on the etching method.

The technical scheme adopted by the invention can achieve the following beneficial effects:

the embodiment of the application discloses a substrate etching method, which is characterized in that a mask layer with a preset pattern is formed on a metal silver layer of a substrate, so that an etching groove with the same shape as the preset pattern can be formed on the metal silver layer in the subsequent etching process. In the etching process, the etching gas is excited into first plasma in the etching cavity, the first plasma comprises at least one of methyl ions and hydrogen ions to etch the mask layer and the metal silver layer, and due to the fact that the mask layer is provided with the preset pattern, an etching groove can be formed in the metal silver layer along with the etching. Meanwhile, during the etching process, both methyl ions and hydrogen ions can react with metallic silver, and AgH or AgCH formed due to the reaction₃Can not exist stably, so that the products can not be stably attached to the surface of the reaction groove, but can be extracted with the gas flow to the etching along with the etchingOutside the cavity, when the etching groove is formed on the metal silver layer of the substrate by adopting the etching method, the conditions that reaction products are adhered and accumulated on the surface and the inner wall of the etching groove can not occur, the normal formation of the etching groove is ensured, and the etching success rate is improved. .

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a prior art product for etching metallic silver;

FIG. 2 is a process diagram of a method for etching a substrate according to an embodiment of the present invention;

FIG. 3 is a diagram showing the actual effect of a product etched by the method for etching a substrate according to the embodiment of the present invention;

FIG. 4 is a diagram illustrating another practical effect of a product etched by the method for etching a substrate according to the embodiment of the present invention;

FIG. 5 is a flow chart of a method for etching a substrate according to an embodiment of the present invention.

Description of reference numerals:

100-etching chamber, 200-upper electrode, 300-lower electrode, 400-air inlet pipeline, 500-air outlet pipeline, 700-substrate, 810-second plasma, 820-first plasma, 830-silver molecule, 840-etching by-product, 910-metallic silver layer, 930-silver oxide.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical solutions disclosed in the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

As shown in fig. 2-5, the embodiment of the invention discloses an etching method of a substrate, by which an etching trench can be formed on the substrate. The etching method comprises the following steps:

and S11, forming a mask layer with a preset pattern on the metal silver layer of the substrate. Optionally, a mask layer may be formed on the metal silver layer of the substrate by covering materials such as photoresist on the metal silver layer in advance, and performing processes such as exposure and development, so that the mask layer has a predetermined pattern, the shape of the predetermined pattern may be set according to actual requirements, and the mask layer with the predetermined pattern may be formed by controlling corresponding parameters in the exposure process. Of course, the mask layer may be not only a photoresist mask layer, but also a mask layer formed of other materials such as silicon oxide, or the mask layer may include not only a photoresist mask layer but also a mask layer formed of other materials. Accordingly, the mask layer may be formed by spraying, spin coating, or the like, or may be formed by deposition, or the like.

And S12, introducing etching gas into the etching cavity, exciting the etching gas as a first plasma, and etching the mask layer and the metal silver layer to form an etching groove on the metal silver layer. Specifically, the etching gas may be dissociated into the first plasma by high frequency oscillation under the action of the electromagnetic field. In the excitation process, the etching gas introduced into the etching chamber may include only one gas or may be an etching gas formed by mixing a plurality of gases. The flow of the etching gas, the frequency of the upper radio frequency power supply and the lower radio frequency power supply of the etching device, the power of the upper radio frequency power supply and the lower radio frequency power supply, the air pressure in the etching chamber, the process temperature and the current proportion of the etching and other parameters can be determined according to the actual requirements such as the etching efficiency and the like, and the parameters are not limited here. Correspondingly, in the process of etching the mask layer and the metal silver layer through the first plasma, the etching time can be determined according to actual requirements, so that the depth of an etched groove formed in the metal silver layer can meet the requirements. Of course, the shape of the etched trench formed in the metallic silver layer is the same as the predetermined pattern of the mask layer.

In the above process, the first plasma formed by exciting the etching gas includes at least one of methyl ions and hydrogen ions. Specifically, the etching gas may be CH₄In this case, it is ensured that the first plasma formed by exciting the etching gas includes methyl ions and hydrogen ions. Of course, the etching gas can be replaced by other gases, so long as the first plasma formed by exciting the etching gas includes methyl ions and hydrogen ions, for example, the etching gas can be H₂And CH₃The etching gas may be excited to form methyl ions and hydrogen ions.

The embodiment of the application discloses a substrate etching method, which is characterized in that a mask layer with a preset pattern is formed on a metal silver layer of a substrate, so that an etching groove with the same shape as the preset pattern can be formed on the metal silver layer in the subsequent etching process. In the etching process, the etching gas is excited into first plasma in the etching cavity, the first plasma comprises at least one of methyl ions and hydrogen ions to etch the mask layer and the metal silver layer, and due to the fact that the mask layer is provided with the preset pattern, an etching groove can be formed in the metal silver layer along with the etching. Meanwhile, during the etching process, both methyl ions and hydrogen ions can react with metallic silver, and AgH or AgCH formed due to the reaction₃The etching solution can not exist stably, so that the product can not be stably attached to the surface of the reaction groove, but can be extracted out of the etching cavity along with the air flow along with the etching, and further, when the etching groove is formed on the metal silver layer of the substrate by adopting the etching method, the reaction product can not be adhered and accumulated on the surface and the inner wall of the etching groove, the normal formation of the etching groove is ensured, and the etching success rate is improved.

Optionally, before the step S2, the method may further include:

and S21, introducing bombardment gas into the etching cavity, exciting the bombardment gas to be a second plasma, and destroying the metal bond of the metal silver layer by a user. That is to say, in the etching process, before the etching gas is introduced, the bombardment gas can be introduced into the etching chamber, and under the action of the second plasma excited by the bombardment gas, the metal bond inside the metal silver can be destroyed, and the impurities such as the oxide of the metal silver layer can be removed, thereby reducing the difficulty in the subsequent etching process.

Specifically, the bombarding gas can be dissociated into the second plasma by high-frequency oscillation under the action of the electromagnetic field. Similarly, in the process of forming the second plasma, various parameters in the etching equipment can be flexibly selected according to actual requirements. The bombardment gas can be argon gas, and the argon ions generated by excitation can destroy the internal metal bonds of the metal silver by means of physical bombardment.

Of course, there are many kinds of plasmas that break down the internal metallic bond of metallic silver, and helium ions and nitrogen ions can also break down the internal metallic bond of metallic silver by means of physical bombardment. Further, the bombardment gas may be helium or nitrogen, and of course, the bombardment gas may be other gases that can be excited to generate at least one of argon ions, helium ions and nitrogen ions, which are not listed here for brevity.

In the above embodiment, with the continuous progress of the etching operation, the steps S12 and S21 may be performed cyclically, that is, the bombardment of the metal silver layer and the etching of the metal silver layer are performed alternately, by adopting the above technical scheme, the difficulty of etching the metal silver layer in the whole etching process can be ensured to be relatively small, and the etching efficiency and the etching effect are improved. More specifically, the duration of the single operation of the steps S12 and S21 may be determined according to actual parameters such as the flow rate of the gas, and is not limited herein, and similarly, the total number of cycles of the steps S12 and S21 may be determined according to actual conditions such as the depth of the etched trench to be formed.

As described above, in order to prevent byproducts generated by etching the metallic silver layer from adhering to the surface of the etched trench, at least one of methyl ions and hydrogen ions may be included in the first plasma, and optionally at least one of argon ions, helium ions and nitrogen ions may be included in the first plasma, that is, the etching gas includes both plasma for reacting with the metallic silver layer and plasma for destroying inner metal parts of the metallic silver layer. Generally, by adopting the technical scheme, the metal bond of the metal silver layer can be synchronously destroyed in the etching process, so that methyl ions and/or hydrogen ions react with the metal silver with the destroyed metal bond, the difficulty of the etching work can be reduced, and the etching efficiency is improved.

Specifically, in the above technical solution, the etching gas may include CH₄And the etching gas can also comprise argon gas, helium gas, nitrogen gas and the like which can generate at least one of argon ions, helium ions and nitrogen ions, so that the first plasma can not only bombard the metallic silver layer to damage metallic bonds, but also react with the metallic silver layer to etch the metallic silver layer, and an etching groove can be formed on the metallic silver layer more easily.

As described above, in the process of etching the metal silver layer by the methyl ions and/or the hydrogen ions, each parameter can be flexibly determined according to actual requirements. Optionally, when the mask layer and the metal silver layer are etched in the etching chamber, the frequency of the upper radio frequency power supply and the frequency of the lower radio frequency power supply are both 13.56MHz, the power of the upper radio frequency power supply is 600-1500W, the power of the lower radio frequency power supply is 100-500W, the process pressure is 3-20 mT, the temperature is 20-50 ℃, and the current ratio is 0.2-0.8. In the above case, the efficiency of the etching work is relatively high.

Furthermore, when the mask layer and the metal silver layer are etched in the etching cavity, the power of an upper radio frequency power supply is 800W, the power of a lower radio frequency power supply is 300W, the process air pressure is 5mT, the temperature is 30 ℃, and the current ratio is 0.5. As described above, the etching gas may include CH₄The flow rate may be 20 sccm.

In addition, before the step S12, S21 may be included, and optionally, during the process of bombarding the metal silver layer, each parameter may be the same as that of the etching process, that is, both the frequency of the adopted upper rf power source and the adopted lower rf power source are 13.56MHz, the power of the upper rf power source is 800W, the power of the lower rf power source is 300W, the process pressure is 5mT, the temperature is 30 ℃, and the current ratio is 0.5. The bombardment gas may be argon gas, and the flow rate of argon gas may be 150 sccm. And, the steps S12 and S21 may be performed alternately, the time for performing the step S21 may be 5S, and the time for performing the step S12 may be 20S, in which case, it is ensured that the efficiency of the whole etching work is relatively high.

As mentioned above, the first plasma may also include at least one of argon ions, helium ions, and nitrogen ions, and optionally, the etching gas includes CH₄And argon, CH₄The flow rate of (2) may be 150sccm, and the flow rate of argon may be 20 sccm. Based on the embodiment, in the process of performing the etching operation, bombardment gas such as argon can be continuously introduced into the etching chamber at a preset flow rate, and CH is intermittently introduced into the etching chamber₄And etching the gas to further improve the working efficiency of etching work.

As mentioned above, the mask layer formed on the metallic silver layer may include a photoresist mask layer, and in another embodiment of the present application, the mask layer includes a photoresist mask layer and an anti-reflective mask layer, and the step S11 may include:

and S111, covering the substrate with a metal silver layer, specifically, forming the metal silver layer on the surface of the substrate in an electroplating or deposition mode, and the like, wherein the thickness of the metal silver layer can be determined according to actual requirements, and is not limited herein.

And S112, covering an anti-reflection mask layer on the metal silver layer, wherein the anti-reflection mask layer can be formed on the surface of the metal silver layer, which is far away from the substrate, in a spin coating mode and the like, and the anti-reflection layer is a bottom anti-reflection coating and can be developed through exposure, so that a structure with a preset pattern is formed. The anti-reflection mask layer can effectively eliminate the standing wave effect in the exposure process and improve the quality of etched lines.

S113, covering a photoresist mask layer on the anti-reflection layer, as described above, the photoresist layer may be covered on the anti-reflection layer by spraying or spin coating, and the thickness of the photoresist may be determined according to parameters such as the selection ratio between the photoresist and the anti-reflection layer and the metal silver layer, and the depth of the etched trench to be formed on the metal silver layer, which is not limited herein.

And S114, exposing the photoresist mask layer and the anti-reflection mask layer to form a mask layer. Specifically, the photoresist mask layer and the antireflective layer are shielded by a structure such as a photomask with a predetermined shape, and the photoresist mask layer and the antireflective mask layer can be developed through exposure to form a mask layer with a predetermined pattern.

Optionally, the step S12 may further include:

and S71, cleaning the residual mask layer on the substrate, specifically, determining the type of cleaning object for cleaning the mask layer according to the specific composition of the mask layer. As described above, the mask layer may include a photoresist mask layer and an anti-reflective mask layer, and correspondingly, the substrate may be cleaned by the EKC270 deglue and/or the SN830 deglue to remove the residual mask layer on the substrate. Of course, other types of cleaning solutions may be used to clean the substrate, such as an organic amine alkaline solution, and the mask layer attached to the surface of the substrate may also be removed.

In the above steps, the temperature of the cleaning liquid, the cleaning time, the cleaning manner, etc. can be determined according to the actual situation, based on the fact that the surface of the substrate is cleaned. Optionally, in the process of cleaning the substrate, the EKC270 photoresist stripper can be heated to 60-80 ℃, preferably 70 ℃, and sprayed on the surface of the substrate at the flow rate of 0.1-1L/min, preferably 0.3L/min, so as to provide the cleaning effect for the surface of the substrate, and the spraying time is 20s-3min, preferably 3 min.

Optionally, the step S71 may further include:

and S81, removing the etching byproducts which are attached on the substrate and contain silver and/or methyl ions. Specifically, the etching by-products attached to the surface of the substrate can be removed by the SN830 photoresist stripper. In the process of cleaning the substrate by the SN830 degumming solution, the substrate can also be cleaned by spraying, the flow rate of the SN830 degumming solution can be 0.1-1L/min, preferably 0.5L/min, and the spraying time can be 1-3min, preferably 2min, so as to ensure that the surface of the substrate is not attached with the etching byproducts containing silver and/or methyl ions.

As described above, in the process of cleaning the substrate by the EKC270 deglued liquid, the temperature of the EKC270 deglued liquid is relatively high, and in order to prevent the substrate from being cracked due to large temperature variation when the substrate is cleaned by the SN830 deglued liquid, optionally, between the above step S71 and step S81, the following steps may be further included:

and S91, reducing the temperature of the substrate, optionally, reducing the temperature of the substrate by allowing the substrate to stand for a period of time, in order to improve the etching efficiency of the substrate, in another embodiment of the present application, the substrate may be purged with gas to improve the cooling efficiency of the substrate, optionally, the substrate may be purged with nitrogen to prevent the substrate from being contaminated, and the purging time may be 1-3min, preferably lasting 3 min.

In order to further improve the cleaning degree of the substrate, optionally, after the step S81 is completed, the HIA may clean the substrate with deionized water for 1 to 5min, specifically for 5min, and after the deionized water cleaning process is completed, the substrate may be continuously purged with nitrogen for 1 to 3min, preferably for 3min, to dry the substrate.

In the above embodiments, the etching process is performed in an etching chamber, and fig. 2 shows an etching apparatus, and schematically shows the etching process of the metallic silver. In fig. 2, the etching apparatus has an etching chamber 100, the etching chamber 100 providing a site for plasma etching. An upper electrode 200 and a lower electrode 300 are installed in the etching chamber 100, the upper electrode 200 and the lower electrode 300 are oppositely arranged, and an upper radio frequency power supply is positioned right above the etching chamber 100 and connected with the upper electrode 200 to provide high-frequency alternating current for the etching process. The upper electrode 200 may be formed of two sets of concentric spiral copper coils, where a high frequency oscillating electromagnetic field is formed to provide the energy required for plasma generation. The lower electrode 300 is located right below the etching chamber 100, and is connected to a lower rf power supply to provide an accelerating electric field for ion bombardment. The substrate 700 is stably attached to the lower electrode 300 by electrostatic attraction. The top of the etching chamber 100 is connected with the gas inlet pipe 400, and etching gas and bombardment gas enter the etching chamber 100 along the gas inlet pipe 400, and then a series of physical and chemical reactions such as dissociation occur inside the etching chamber 100. The exhaust line 500 is located at the middle and lower end of the etching chamber 100 and is connected to a dry pump, which provides power for an exhaust device. Byproducts generated during the etching process are desorbed from the surface of the substrate 700 and then are exhausted from the etching chamber 100 through the exhaust pipe 500.

As shown in fig. 2, dissociation of the gas entering the etching chamber 100 from the gas inlet conduit 400 may generate a first plasma 820 and a second plasma 810, wherein the first plasma 820 comprises methyl ions and/or hydrogen ions, the second plasma 810 comprises at least one of argon ions, helium ions and nitrogen ions, the second plasma 810 may break metallic bonds between the silver molecules 830, the first plasma 820 may react with silver to form etching byproducts 840, the etching byproducts 840 may be exhausted from the exhaust conduit 500 to the outside of the etching chamber 100, and the etching byproducts 840 may specifically include AgH or AgCH₃。

Based on the etching methods provided by the embodiments, the present application also provides a thin film transistor, and the thin film transistor is manufactured based on the etching method provided by any one of the embodiments.

In the above embodiments of the present invention, the difference between the embodiments is mainly described, and different optimization features between the embodiments can be combined to form a better embodiment as long as they are not contradictory, and further description is omitted here in view of brevity of the text.

The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.