Preparation method of tantalum nitride film and semiconductor device

Abstract

The invention provides a preparation method of a tantalum nitride film and a semiconductor device, and belongs to the technical field of semiconductors. The preparation method comprises the following steps: providing a primary corrosion solution which is used for dissolving an oxide; soaking the tantalum nitride sample in the primary corrosion solution; providing a secondary corrosion solution, wherein the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water; and soaking the tantalum nitride sample in the secondary etchant solution, and corroding to obtain the tantalum nitride film. The corrosion rate of the tantalum nitride thin film can be effectively controlled, and the corrosion uniformity of the tantalum nitride thin film is improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a method for preparing a tantalum nitride film and a semiconductor device. Background Art

[0002] Semiconductor devices are electronic devices that use the special electrical properties of semiconductor materials to perform specific functions.

[0003] In the related art, tantalum nitride materials are widely used in thin film resistors and other fields because of their various excellent physical and chemical properties. When processing tantalum nitride materials, dry etching process or wet etching process is often used to prepare tantalum nitride thin film. However, when the dry etching process is applied to tantalum nitride materials, it often faces the dilemma of low selectivity and difficulty in etching, so the wet etching process has become a more commonly used method for processing tantalum nitride materials.

[0004] However, in the wet etching process, the corrosion rate is difficult to control and the corrosion uniformity is also poor, which makes it impossible to meet the process requirements. Summary of the invention

[0005] The embodiment of the present disclosure provides a method for preparing a tantalum nitride film and a semiconductor device, which can effectively control the corrosion rate of the tantalum nitride film and improve its corrosion uniformity. The technical solution is as follows:

[0006] In a first aspect, an embodiment of the present disclosure provides a method for preparing a tantalum nitride thin film, the method comprising:

[0007] providing a primary etching solution, wherein the primary etching solution is used to dissolve oxides;

[0008] Immersing the tantalum nitride sample in the primary etching solution;

[0009] Providing a secondary corrosion solution, wherein the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water;

[0010] The tantalum nitride sample is immersed in the secondary etching solution to be etched to obtain a tantalum nitride film.

[0011] In one implementation of the present disclosure, immersing the tantalum nitride sample in the primary etching solution comprises:

[0012] The tantalum nitride sample is immersed in the primary etching solution for 3 to 5 minutes.

[0013] In one implementation of the present disclosure, immersing the tantalum nitride sample in the primary etching solution further comprises:

[0014] During the soaking of the tantalum nitride sample, the primary etching solution was stirred.

[0015] In another implementation of the present disclosure, after immersing the tantalum nitride sample in the primary etching solution, the method further comprises:

[0016] Taking out the tantalum nitride sample from the primary etching solution;

[0017] The tantalum nitride sample was rinsed with deionized water.

[0018] In another implementation of the present disclosure, a secondary etching solution is provided, comprising:

[0019] The ammonia water, the hydrogen peroxide solution and the pure water are mixed in a ratio of 1:4:20 to obtain the secondary corrosion solution.

[0020] In another implementation of the present disclosure, before immersing the tantalum nitride sample in the secondary etching solution, the method includes:

[0021] The temperature of the secondary etching solution is adjusted to 60-70 degrees Celsius.

[0022] In another implementation of the present disclosure, immersing the tantalum nitride sample in the secondary etching solution comprises:

[0023] The tantalum nitride sample is immersed in the secondary etching solution for 10 to 15 minutes.

[0024] In another implementation of the present disclosure, after immersing the tantalum nitride sample in the secondary etching solution, the method further comprises:

[0025] Taking out the tantalum nitride sample from the secondary etching solution;

[0026] The tantalum nitride sample was rinsed with deionized water.

[0027] In another implementation of the present disclosure, after rinsing the tantalum nitride sample with deionized water, the method further comprises:

[0028] The tantalum nitride sample is dried to obtain a tantalum nitride film.

[0029] In a second aspect, an embodiment of the present disclosure provides a semiconductor device, comprising a tantalum nitride film, wherein the tantalum nitride film is obtained by the preparation method described in the first aspect.

[0030] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0031] Through the preparation method provided by the embodiment of the present disclosure, the tantalum nitride material can be corroded to obtain the desired tantalum nitride film. In the preparation process, a primary corrosion solution is first provided, and the tantalum nitride sample is immersed in the primary corrosion solution. Since the primary corrosion solution can dissolve oxides, the tantalum nitride sample is immersed in the primary corrosion solution, and the oxides on the surface of the tantalum nitride sample can be removed by the primary corrosion solution, thereby laying a good foundation for the subsequent corrosion process. Then a secondary corrosion solution is provided, and the tantalum nitride sample is immersed in the secondary corrosion solution. Since the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water, the tantalum nitride sample immersed in the secondary corrosion solution can be corroded. Moreover, benefiting from the characteristics of ammonia water and hydrogen peroxide, the secondary corrosion solution can achieve uniform corrosion of the tantalum oxide sample.

[0032] In addition, since the oxide on the surface of the tantalum nitride sample has been removed in advance by a primary etching solution, the corrosion rate of the tantalum nitride sample will not be affected by the oxide during the subsequent etching of the tantalum nitride sample by a secondary etching solution, which is conducive to accurately controlling the corrosion rate of the tantalum nitride sample.

[0033] That is to say, through the preparation method provided in the embodiment of the present disclosure, the corrosion rate of the tantalum nitride film can be effectively controlled and its corrosion uniformity can be improved, thereby meeting the process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a flow chart of a method for preparing a tantalum nitride thin film provided in an embodiment of the present disclosure;

[0036] Figure 2 It is a flow chart of another method for preparing tantalum nitride film provided in an embodiment of the present disclosure.

[0037] The above drawings show clear embodiments of the present disclosure, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present disclosure in any way, but to illustrate the concepts of the present disclosure to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0039] The present disclosure provides a method for preparing a tantalum nitride thin film. Figure 1 For a flow chart of the preparation method, see Figure 1 In this embodiment, the preparation method comprises:

[0040] Step 101: providing a primary etching solution.

[0041] Among them, the primary etching solution is used to dissolve the oxide.

[0042] Step 102: Immerse the tantalum nitride sample in a primary etching solution.

[0043] Step 103: providing a secondary etching solution.

[0044] Wherein, the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water.

[0045] Step 104: Immerse the tantalum nitride sample in a secondary etching solution to obtain a tantalum nitride film by etching.

[0046] Through the preparation method provided by the embodiment of the present disclosure, the tantalum nitride material can be corroded to obtain the desired tantalum nitride film. In the preparation process, a primary corrosion solution is first provided, and the tantalum nitride sample is immersed in the primary corrosion solution. Since the primary corrosion solution can dissolve oxides, the tantalum nitride sample is immersed in the primary corrosion solution, and the oxides on the surface of the tantalum nitride sample can be removed by the primary corrosion solution, thereby laying a good foundation for the subsequent corrosion process. Then a secondary corrosion solution is provided, and the tantalum nitride sample is immersed in the secondary corrosion solution. Since the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water, the tantalum nitride sample immersed in the secondary corrosion solution can be corroded. Moreover, benefiting from the characteristics of ammonia water and hydrogen peroxide, the secondary corrosion solution can achieve uniform corrosion of the tantalum oxide sample. In addition, since the oxides on the surface of the tantalum nitride sample have been removed in advance by the primary corrosion solution, the corrosion rate will not be affected by the oxides in the process of corroding the tantalum nitride sample by the secondary corrosion solution, which is conducive to accurately controlling the corrosion rate of the tantalum nitride sample.

[0047] That is to say, through the preparation method provided in the embodiment of the present disclosure, the corrosion rate of the tantalum nitride film can be effectively controlled and its corrosion uniformity can be improved, thereby meeting the process requirements.

[0048] Figure 2 A flowchart of another method for preparing a tantalum nitride film provided in an embodiment of the present disclosure is provided in Figure 2 In this embodiment, the preparation method comprises:

[0049] Step 201: providing a primary etching solution.

[0050] Among them, the primary etching solution is used to dissolve the oxide.

[0051] Exemplarily, the primary etching solution is a strong acid solution, such as a hydrochloric acid solution, etc. In this way, the oxide can be effectively dissolved by the primary etching solution.

[0052] It is worth noting that the oxide on the surface of the tantalum oxide sample is generally tantalum pentoxide. The hydrochloric acid solution can produce a chemical reaction with tantalum pentoxide, thereby dissolving tantalum pentoxide. The chemical formula is as follows:

[0053] Ta2O5+10HCl=2TaCl5+5H2O.

[0054] Step 202: Immerse the tantalum nitride sample in a primary etching solution.

[0055] In the above implementation, the tantalum nitride sample is placed in a container where the primary etching solution is located, ensuring that the tantalum nitride sample is completely immersed in the primary etching solution. Since the primary etching solution can dissolve oxides, the oxides that may exist on the surface of the tantalum nitride sample can be removed by the primary etching solution. In addition, the primary etching solution will not have too much impact on the tantalum nitride sample.

[0056] In addition, since the oxide on the surface of the tantalum nitride sample has been removed by the primary etching solution, the corrosion rate of the tantalum nitride sample will not be affected by the oxide during the subsequent etching of the tantalum nitride sample by the secondary etching solution, which is conducive to accurately controlling the corrosion rate of the tantalum nitride sample.

[0057] Exemplarily, the tantalum nitride sample is immersed in a primary etching solution for 3 to 5 minutes.

[0058] In the above implementation, the immersion time of the tantalum nitride sample is controlled within 3 to 5 minutes. On the one hand, it can ensure that the primary corrosion solution fully dissolves the oxide on the surface of the tantalum nitride sample. On the other hand, it can also avoid the primary corrosion solution from causing excessive impact on the tantalum oxide sample itself.

[0059] In this embodiment, the tantalum nitride sample is immersed in the corrosion solution for 3 minutes. Of course, in other embodiments, it can also be other time lengths within the above time length range, such as 5 minutes, etc., and the present disclosure does not limit this.

[0060] In this embodiment, the etching solution is stirred once during the soaking of the tantalum nitride sample.

[0061] In this way, sufficient reaction between the primary etching solution and the oxide can be ensured, so that the primary etching solution can evenly dissolve the oxide on the surface of the tantalum nitride sample.

[0062] It is worth noting that the stirring time can also be selected according to actual conditions, and the present disclosure does not impose any restrictions on this.

[0063] Step 203: Take out the tantalum nitride sample from the primary etching solution and rinse the tantalum nitride sample with deionized water.

[0064] In the above implementation, the tantalum nitride sample is rinsed with deionized water to clean off the primary etching solution remaining on the surface of the tantalum nitride sample.

[0065] Step 204: providing a secondary etching solution.

[0066] Wherein, the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water.

[0067] In the above implementation, the characteristics of ammonia water and hydrogen peroxide can be utilized to effectively corrode the tantalum nitride sample.

[0068] The corrosion principle of tantalum nitride by the secondary etching solution is explained below.

[0069] Ammonia is a weak base. In aqueous solution, it partially ionizes into ammonium ions and hydroxide ions. In the process of corroding tantalum nitride, hydroxide ions can react with the surface of tantalum nitride. For example, it may form some tantalum hydroxide complexes with the tantalum element in tantalum nitride, thereby destroying the surface structure of tantalum nitride.

[0070] Hydrogen peroxide is a strong oxidant. In solution, it can decompose to produce active oxygen species with strong oxidizing properties, such as hydroxyl radicals. Hydroxyl radicals are highly reactive and can attack the chemical bonds on the surface of tantalum nitride. They can react with the nitrogen-tantalum bonds in tantalum nitride, causing the nitrogen element to be separated in the form of nitrogen-containing compounds, and the tantalum element to be oxidized, thereby accelerating the corrosion process of tantalum nitride.

[0071] In this embodiment, ammonia water, hydrogen peroxide and pure water are mixed in a ratio of 1:4:20 to obtain a secondary corrosion solution.

[0072] In the process of preparing the secondary corrosion solution, first measure an appropriate amount of ammonia water and pour it into the reaction container, then add the corresponding volume of hydrogen peroxide, and finally add the specified volume of water, stir evenly, and make the solution fully mixed.

[0073] In the above implementation, ammonia water, hydrogen peroxide and pure water are mixed in a ratio of 1:4:20 to form the following

[0074] Beneficial effects:

[0075] (1) Good corrosion effect: Hydrogen peroxide has strong oxidizing properties and can react with tantalum nitride to break the chemical bonds on the surface of tantalum nitride, thereby achieving corrosion. Ammonia is weakly alkaline and can promote the decomposition of hydrogen peroxide, produce more active substances such as hydroxyl free radicals with strong oxidizing properties, and accelerate the corrosion process. The synergistic effect of the two can effectively corrode tantalum nitride, forming a specific microstructure on its surface or achieving the required roughness to meet different application requirements.

[0076] (2) High corrosion uniformity: Under the above-mentioned ratio of ammonia water, hydrogen peroxide and pure water, the distribution of the components of the solution is relatively uniform, which can make the corrosion reaction proceed evenly on the surface of tantalum nitride, avoid excessive or insufficient local corrosion, ensure the consistency of the surface quality and performance of tantalum nitride, and facilitate the subsequent precise processing and use of tantalum nitride materials.

[0077] (3) The corrosion rate is easy to control: By adjusting the reaction temperature, time and other conditions, the corrosion rate can be controlled more accurately within a certain range. For example, if the temperature is increased, the molecular movement will be accelerated and the reaction rate will increase; if the temperature is lowered, the reaction rate will slow down, which is convenient for flexible adjustment according to specific needs to obtain the ideal corrosion effect.

[0078] (4) Relatively safe operation: The secondary corrosion solution of the above ratio is relatively mild in corrosiveness. Compared with some highly corrosive corrosive agents, it poses less harm to operators and equipment, and can be operated under conventional experimental conditions without the need for special protective equipment and harsh operating environment, thus reducing experimental costs and operating difficulties.

[0079] (5) Good environmental friendliness: The secondary corrosion solution with the above ratio is relatively environmentally friendly. Its components are easy to decompose or process in the natural environment, and will not produce harmful substances that are difficult to degrade. It has less pollution to the environment, conforms to the development concept of green chemistry, and reduces the negative impact on the environment.

[0080] Step 205: Adjust the temperature of the secondary etching solution to 60-70 degrees Celsius.

[0081] Exemplarily, the secondary etching solution is added into a heating container, and the secondary etching solution is heated by the heating container so that the temperature of the secondary etching solution reaches 60 to 70 degrees Celsius.

[0082] In the above temperature range, the secondary etching solution can fully corrode the tantalum nitride sample to ensure a high etching efficiency.

[0083] When the temperature rises to 60-70 degrees Celsius, the chemical reaction rate can be accelerated. According to the Arrhenius formula, as the temperature rises, the reaction rate constant k increases. For the reaction of ammonia water with tantalum nitride and the reaction of hydrogen peroxide with tantalum nitride, when the temperature rises, the rate at which ammonia water ionizes hydroxide ions will increase, and the rate at which hydrogen peroxide decomposes to produce hydroxyl radicals will also increase. Moreover, the increase in temperature accelerates the diffusion rate of these active substances (hydroxyl ions, hydroxyl radicals, etc.) in the solution, and they can contact and react with the surface of the tantalum nitride sample more frequently, thereby increasing the corrosion effect on the tantalum nitride sample.

[0084] In this embodiment, the temperature of the secondary etching solution is adjusted to 65 degrees Celsius. Of course, in other embodiments, the temperature of the secondary etching solution can also be adjusted to other temperatures within the above temperature range, and the present disclosure is not limited thereto.

[0085] Exemplarily, the heating container is a high temperature resistant and corrosion resistant reaction container, such as a stainless steel reactor lined with polytetrafluoroethylene, etc., so as to withstand the temperature of 60 to 70 degrees Celsius and the corrosiveness of the solution.

[0086] Step 206: Immerse the tantalum nitride sample in a secondary etching solution.

[0087] In the above implementation, the tantalum nitride sample is placed in a container containing the secondary etching solution to ensure that the tantalum nitride sample is completely immersed in the secondary etching solution. Since the secondary etching solution is a mixed solution of ammonia water, hydrogen peroxide and pure water, the tantalum nitride sample can be evenly and efficiently corroded.

[0088] Exemplarily, the tantalum nitride sample is immersed in the secondary etching solution for 10 to 15 minutes.

[0089] In the above implementation, the immersion time of the tantalum nitride sample is controlled within 10 to 15 minutes, which can ensure that the secondary corrosion solution fully corrodes the tantalum nitride sample as expected, and can also avoid excessive corrosion.

[0090] In this embodiment, the tantalum nitride sample is immersed in the secondary etching solution for 12 minutes. Of course, in other embodiments, it can also be other time lengths within the above time length range, such as 14 minutes, etc., and the present disclosure does not limit this.

[0091] It is worth noting that during the process of etching the tantalum nitride sample with the secondary etching solution, the state of the secondary etching solution and the condition of the tantalum nitride sample are continuously detected to ensure that the etching process is carried out according to the expected plan.

[0092] Step 207: Take out the tantalum nitride sample from the secondary etching solution and rinse the tantalum nitride sample with deionized water.

[0093] In the above implementation, the tantalum nitride sample is rinsed with deionized water to clean off the secondary etching solution remaining on the surface of the tantalum nitride sample.

[0094] Step 208: Dry the tantalum nitride sample to obtain a tantalum nitride film.

[0095] In the above implementation, the deionized water remaining on the surface of the tantalum nitride sample is dried to obtain the final tantalum nitride film.

[0096] The preparation method provided by the embodiment of the present disclosure can improve the corrosion uniformity and help control the corrosion rate. The following are respectively described:

[0097] To improve corrosion uniformity:

[0098] (1) The uniformity of solution mixing is enhanced.

[0099] When the temperature rises to 60-70 degrees Celsius, the convection and diffusion process of the secondary etching solution will be accelerated. When the secondary etching solution is heated, the thermal motion of the molecules becomes more intense. This allows the ammonia and hydrogen peroxide in the secondary etching solution to be more evenly distributed throughout the reaction system. For example, without heating, the solution may cause uneven corrosion due to local concentration differences, but at 60-70 degrees Celsius, this concentration difference will be reduced due to rapid diffusion, making the distribution of the corrosive agent on the surface of tantalum nitride more uniform, thereby improving the uniformity of corrosion.

[0100] (2) Uniform activation of reactive sites.

[0101] There are many potential reactive sites on the surface of tantalum nitride. At a temperature of 60 to 70 degrees Celsius, the activity of ammonia and hydrogen peroxide increases. On the one hand, the hydroxide ions ionized by ammonia can better interact with the metal atoms on the surface of tantalum nitride, and the active oxygen species produced by hydrogen peroxide can also attack the chemical bonds on the surface of tantalum nitride more evenly. As the temperature rises, the initiation of these reactions at various locations on the surface of tantalum nitride is more synchronous, and there will be no local reaction that is too fast or too slow, so the uniformity of corrosion can be improved.

[0102] In terms of controlling corrosion rate:

[0103] (1) Application of Arrhenius formula.

[0104] According to the Arrhenius formula, temperature is an important factor affecting the reaction rate constant. In this system, when the temperature is stable at 60-70 degrees Celsius, the reaction rate constant will stabilize at a relatively predictable value. This is because the increase in temperature accelerates the reaction rate based on the quantitative relationship of this formula. As long as the temperature, ammonia concentration, hydrogen peroxide concentration and other conditions are kept relatively stable, the corrosion rate can be roughly estimated and controlled by these parameters. For example, if the corrosion rate is found to be too fast, the temperature can be appropriately lowered or the concentration of ammonia and hydrogen peroxide can be reduced to adjust it.

[0105] (2) The observability of the reaction process is enhanced.

[0106] At 60 to 70 degrees Celsius, the reaction rate is moderate. The corrosion process is neither too slow to be observed due to the low temperature nor too fast to be controlled due to the instantaneous completion of the reaction. Such temperature conditions make it convenient for experimenters to monitor the corrosion process in real time. The corrosion process can be tracked by observing the color change of the solution, the generation of gas, or measuring the mass loss of tantalum nitride, and the reaction conditions can be adjusted in time according to the observation results, thereby effectively controlling the corrosion rate.

[0107] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0108] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for preparing a tantalum nitride thin film, characterized in that: The preparation method comprises: providing a primary etching solution, wherein the primary etching solution is used to dissolve oxides; Immersing the tantalum nitride sample in the primary etching solution; Providing a secondary corrosion solution, wherein the secondary corrosion solution is a mixed solution of ammonia water, hydrogen peroxide and pure water; The tantalum nitride sample is immersed in the secondary etching solution to obtain a tantalum nitride film by etching.

2. The preparation method according to claim 1, characterized in that: Soaking the tantalum nitride sample in the primary etching solution comprises: The tantalum nitride sample is immersed in the primary etching solution for 3 to 5 minutes.

3. The preparation method according to claim 1, characterized in that: Soaking the tantalum nitride sample in the primary etching solution also includes: During the soaking of the tantalum nitride sample, the primary etching solution was stirred.

4. The preparation method according to claim 1, characterized in that: After immersing the tantalum nitride sample in the primary etching solution, the method comprises: Taking out the tantalum nitride sample from the primary etching solution; The tantalum nitride sample was rinsed with deionized water.

5. The preparation method according to claim 1, characterized in that: Provides secondary corrosion solutions, including: The ammonia water, the hydrogen peroxide solution and the pure water are mixed in a ratio of 1:4:20 to obtain the secondary corrosion solution.

6. The preparation method according to claim 1, characterized in that: Before immersing the tantalum nitride sample in the secondary etching solution, the method comprises: The temperature of the secondary etching solution is adjusted to 60-70 degrees Celsius.

7. The preparation method according to claim 1, characterized in that: The tantalum nitride sample is immersed in the secondary etching solution, comprising: The tantalum nitride sample is immersed in the secondary etching solution for 10 to 15 minutes.

8. The preparation method according to claim 1, characterized in that: After immersing the tantalum nitride sample in the secondary etching solution, the method comprises: Taking out the tantalum nitride sample from the secondary etching solution; The tantalum nitride sample was rinsed with deionized water.

9. The preparation method according to claim 8, characterized in that: After rinsing the tantalum nitride sample with deionized water, including: The tantalum nitride sample is dried to obtain a tantalum nitride film.

10. A semiconductor device, characterized in that: It comprises a tantalum nitride film, and the tantalum nitride film is obtained by the preparation method according to any one of claims 1 to 9.

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