阅读说明：本技术 具有氮化铝膜层的基材的加工方法及滤波器的制备方法 (Processing method of substrate with aluminum nitride film layer and preparation method of filter ) 是由 邹斌 蔡丹华 史爽 于 2021-09-07 设计创作，主要内容包括：本发明提供了一种具有氮化铝膜层的基材的加工方法及滤波器的制备方法。在执行湿法制程之后进行酸洗,并在酸洗后利用亲水性有机溶剂执行脱水处理,以去除氮化铝膜层上的水分,避免氮化铝和水发生化学反应而产生固体杂质,提高了氮化铝膜层的表面清洁度和平坦度,改善后续形成在氮化铝膜层上的薄膜品质。(The invention provides a processing method of a base material with an aluminum nitride film layer and a preparation method of a filter. The wet process is performed and then acid cleaning is performed, and the hydrophilic organic solvent is used for performing dehydration treatment after acid cleaning to remove water on the aluminum nitride film layer, so that solid impurities generated by chemical reaction of aluminum nitride and water are avoided, the surface cleanliness and the flatness of the aluminum nitride film layer are improved, and the quality of a film subsequently formed on the aluminum nitride film layer is improved.)

1. A processing method of a substrate with an aluminum nitride film layer is characterized by comprising the following steps:

performing a wet process, and pickling the substrate after the wet process;

after the acid washing, performing dehydration treatment using a hydrophilic organic solvent to remove moisture on the surface of the aluminum nitride; and the number of the first and second groups,

and drying the base material, wherein the hydrophilic organic solvent is volatilized in the drying process.

2. The method of claim 1, wherein the acid solution used for pickling has a pH of 5.5 to 6.5.

3. The method of claim 1, wherein the acid solution used for pickling comprises a hydrofluoric acid solution or a carbonic acid solution.

4. The method of processing a substrate having an aluminum nitride film layer according to claim 1, wherein the dehydration treatment comprises: immersing the substrate into the hydrophilic organic solvent; alternatively, the hydrophilic organic solvent is sprayed to the surface of the substrate.

5. The method for processing a substrate having an aluminum nitride film layer according to claim 1, wherein the hydrophilic organic solvent comprises an alcohol organic solvent and/or an ether organic solvent.

6. The method of claim 1, wherein the drying temperature of the drying process is 20 ℃ to 100 ℃.

7. The method of claim 1, wherein the wet process comprises a wet etching process and/or a wet cleaning process.

8. The method of claim 7, wherein the wet cleaning process comprises a chemical solution cleaning and/or a pure water cleaning.

9. The method of processing a substrate having an aluminum nitride film layer according to claim 1, wherein the dehydration treatment is performed within 30 seconds after the acid washing.

10. A method of making a filter, comprising: sequentially forming a bottom electrode, an aluminum nitride piezoelectric layer and a top electrode on a substrate;

wherein after forming the aluminum nitride piezoelectric layer and before forming the top electrode, further comprising: treating the substrate with a process according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of semiconductors, in particular to a processing method of a base material with an aluminum nitride film layer and a preparation method of a filter.

Background

Aluminum nitride (AlN) is a common processing material in the semiconductor field, and may be used, for example, in filters for piezoelectric films, or in light emitting diodes for underlayers, etc. However, for the processing of devices containing aluminum nitride films, the appearance of the current aluminum nitride layer is often abnormal, and the subsequent films are often abnormal, and the problems of abnormal electrical test and poor reliability of the products are also easily caused.

Disclosure of Invention

The invention aims to provide a method for processing a base material with an aluminum nitride film layer, which aims to solve the problem that the conventional aluminum nitride film layer is easy to have abnormal appearance in the processing process.

In order to solve the above technical problems, the present invention provides a method for processing a substrate having an aluminum nitride film layer, comprising: performing a wet process, and pickling the substrate after the wet process; after the acid washing, performing dehydration treatment using a hydrophilic organic solvent to remove moisture on the surface of the aluminum nitride; and drying the base material, wherein the hydrophilic organic solvent is volatilized in the drying process.

Alternatively, the PH of the acid solution used for the acid wash may be, for example, between 5.5 and 6.5. Specifically, the acid solution used for the acid cleaning may include a hydrofluoric acid solution or a carbonic acid solution.

Optionally, the dehydration treatment includes: immersing the substrate into the hydrophilic organic solvent; alternatively, the hydrophilic organic solvent is sprayed to the surface of the substrate.

Optionally, the hydrophilic organic solvent includes an alcohol organic solvent and/or an ether organic solvent.

Alternatively, the drying temperature of the drying treatment is, for example, 20 ℃ to 100 ℃.

Optionally, the wet process includes a wet etching process and/or a wet cleaning process. Wherein the wet cleaning comprises chemical solution cleaning and/or pure water cleaning.

Another object of the present invention is to provide a method for manufacturing a memory, including: a bottom electrode, an aluminum nitride piezoelectric layer and a top electrode are sequentially formed on a substrate. Wherein after forming the aluminum nitride piezoelectric layer and before forming the top electrode, further comprising: the substrate is treated using the processing method described above.

In the processing method of the base material with the aluminum nitride film layer, the base plate is subjected to acid cleaning treatment after the wet process, and at the moment, if aluminum hydroxide is generated on the aluminum nitride film layer, the generated aluminum hydroxide can be effectively removed through acid cleaning. And after acid cleaning, a hydrophilic organic solvent is utilized to perform dehydration treatment so as to remove the moisture on the aluminum nitride film layer, so that the chemical reaction between the residual moisture and the aluminum nitride is avoided, particularly the reaction aggravation between the residual moisture and the aluminum nitride in the drying process can be prevented, the surface cleanliness and the flatness of the aluminum nitride film layer are improved, the quality of a film subsequently formed on the aluminum nitride film layer can be correspondingly improved, and the product yield and the product performance on the substrate are improved. Moreover, the hydrophilic organic solvent is adopted, so that the moisture on the base material can be quickly removed, and the hydrophilic organic solvent can be directly volatilized in the drying process without influencing the base material.

Drawings

FIG. 1 is a flow chart illustrating a method for processing a substrate having an aluminum nitride film.

Fig. 2 is a schematic structural view of the processing method shown in fig. 1 during a processing process thereof.

Fig. 3 is a flow chart illustrating a method for processing a substrate having an aluminum nitride film layer according to an embodiment of the invention.

Fig. 4 is a schematic structural view of the process shown in fig. 3 during the process.

Detailed Description

As described in the background art, in the current semiconductor process including an aluminum nitride film, the appearance of the current film and the appearance of the subsequent film are abnormal, which affects the electrical performance and reliability of the product. After the inventor of the present invention has comprehensively studied the processing technology of the aluminum nitride film, it is found that one important reason for causing the appearance abnormality of the current film and the subsequent film is as follows: when a substrate containing an aluminum nitride film is subjected to a wet process, solid impurities are easily generated on the surface of the aluminum nitride.

Referring specifically to FIG. 1, one wet process performed on a substrate includes, for example: chemical cleaning is performed, followed by pure water cleaning to remove the chemical on the surface of the substrate, and then the substrate is dried. The inventors have conducted the above wet processAfter the research, the aluminum nitride film layer is found to generate solid aluminum hydroxide (Al (OH) by the chemical reaction of aluminum nitride in the wet process₃) Impurities are attached to the surface of the aluminum nitride film layer, and the generated aluminum hydroxide impurities can cause abnormal appearance of a subsequent film layer process, cause abnormal electrical test and poor reliability of a product, and further cause product scrapping.

After further research by the inventor, it is known that an important link of the aluminum nitride generating the solid aluminum hydroxide impurity through the chemical reaction is that the wet process contains water, and the aluminum nitride and the water generate a slow hydrolysis reaction after contacting the water to generate the aluminum hydroxide attached to the surface of the aluminum nitride layer. In particular, the substrate with water is dried at high temperature directly after the wet process, so that the reaction of aluminum nitride is accelerated under heating conditions, further aggravating the generation of aluminum hydroxide. Specifically, referring to fig. 2, when aluminum hydroxide 21 is easily generated on the surface of the aluminum nitride film 20 in a wet process, and then the aluminum nitride film 20 is deposited to form the film 30, the presence of the aluminum hydroxide 21 easily causes unevenness and abnormal appearance on the surface of the film 30, and reduces the bonding force between the film 30 and the aluminum nitride film 20.

In view of the above, the present invention provides a method for processing a substrate having an aluminum nitride film layer, comprising: performing a wet process, and performing dehydration treatment by using a hydrophilic organic solvent after the wet process to remove moisture on the surface of the aluminum nitride; and then, drying the base material, wherein the hydrophilic organic solvent is volatilized in the drying process. Namely, after the wet process, the substrate is dehydrated, so that the moisture on the surface of the aluminum nitride is removed, the aluminum nitride is prevented from being hydrolyzed to generate aluminum hydroxide, the surface flatness and the cleanliness of the aluminum nitride film are effectively improved, the quality of the film subsequently formed on the aluminum nitride film is improved, and the adhesion performance between the aluminum nitride film and the film above the aluminum nitride film is guaranteed.

The method for processing a substrate having an aluminum nitride film and the method for manufacturing a filter according to the present invention are further described in detail with reference to fig. 3-4 and specific examples, wherein fig. 3 is a schematic flow chart of the method for processing a substrate having an aluminum nitride film according to an embodiment of the present invention, and fig. 4 is a schematic structural view of the method shown in fig. 3 during the processing process. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Referring to fig. 3 and 4, a method for processing a substrate (e.g., a wafer) having an aluminum nitride film layer according to the present embodiment includes: performing a wet process, and performing acid cleaning on the substrate after the wet process; after acid washing, dehydration treatment is performed by using a hydrophilic organic solvent to remove moisture on the surface of the aluminum nitride film layer 200; thereafter, the substrate 100 is subjected to a drying process, and the hydrophilic organic solvent is volatilized during the drying process.

The wet process may be any process using a wet solution, such as a wet etching process and/or a wet cleaning process. As long as the aluminum nitride film 200 is exposed to the wet solution during the wet process, the processing method provided in this embodiment can be used. The following is a non-limiting list of several aspects of wet processing.

In the first case, a wet etching process is performed, which may be a wet etching process for the aluminum nitride film 200 or a wet etching process for other films besides the aluminum nitride film.

In the second case, after the wet etching process is performed, a wet cleaning process is performed.

In the third case, a wet clean process is performed. It should be appreciated that the process performed before the wet cleaning process is not limited, and may be any process, such as a dry etching process.

The wet cleaning process can be used to remove residues, contaminants, particles, etc. on the surface of the substrate (including the surface of the aluminum nitride film). And, for wet cleaning processes, it may include chemical cleaning and/or pure water cleaning. Specifically, it is preferable to perform cleaning with a chemical agent (the cleaning with the chemical agent includes, for example, acid cleaning and/or alkali cleaning) and then cleaning with pure water to remove the chemical agent on the surface of the substrate. Of course, in practical applications, the wet cleaning process may also include only pure water cleaning.

Further, the substrate 100 is acid-washed after the wet process. In this case, if aluminum hydroxide is already formed on the surface of the aluminum nitride film layer 200, the aluminum hydroxide on the surface of the aluminum nitride film layer can be effectively removed by the acid cleaning. In order to prevent the aluminum nitride film layer from being corroded by a large amount, the aluminum nitride film layer is not usually subjected to an acid cleaning treatment in the field. However, in this embodiment, the base material may be washed with a weak acid solution, and since the erosion rate of the weak acid to the aluminum hydroxide is much greater than the erosion rate of the weak acid to the aluminum nitride, the weak acid is used to perform the treatment in this embodiment, so that not only the aluminum hydroxide on the surface of the aluminum nitride film layer 200 can be effectively removed, but also the aluminum nitride film layer 200 can be prevented from being eroded by the weak acid solution. In this embodiment, the PH of the acid solution used for the acid cleaning is, for example, 5.5 to 6.5, and specifically, the acid cleaning solution used for the acid cleaning is, for example, a hydrofluoric acid solution or a carbonic acid solution, which are weakly acidic. In practice, the substrate may be immersed in an acid solution for acid washing to rapidly remove aluminum hydroxide from the aluminum nitride film.

After the acid washing, the dehydration treatment is carried out by using a hydrophilic organic solvent, so that the moisture on the surface of the base material can be effectively removed, and the aluminum nitride can be prevented from reacting to generate aluminum hydroxide. The dehydration treatment method includes, for example: immersing the substrate 100 into the hydrophilic organic solvent; alternatively, the moisture on the substrate may be removed by spraying a hydrophilic organic solvent onto the surface of the substrate. In particular embodiments, the substrate 100 may also be kept spinning (Spin) while spraying the hydrophilic organic solvent onto the surface of the substrate to improve the efficiency of removing moisture from the surface of the substrate. As the hydrophilic organic solvent, an alcohol organic solvent (e.g., ethanol solution, isopropanol solution, etc.) or an ether organic solvent may be used.

In this embodiment, the substrate 100 further comprises an acid cleaning process after the wet process, and then the dehydration process is performed, wherein the time interval between the acid cleaning process and the dehydration process can be controlled within 30s, for example, within 15 s. Namely, the substrate can be quickly dehydrated after acid cleaning, so as to avoid the aluminum hydroxide generated by the excessive retention of the water on the aluminum nitride film layer 200.

However, it should be appreciated that in other embodiments, if the substrate is subjected to a wet etching process (e.g., after wet etching), instead of the acid cleaning process, the time interval between the wet etching process and the dehydration process may be controlled within 30s (or even within 15 s) to ensure that the water on the aluminum nitride film is removed earlier.

With continued reference to fig. 3, the substrate is subjected to a drying process after the dehydration process, which may be at a temperature of, for example, between 20 ℃ and 100 ℃. Since the substrate does not carry moisture on its surface after dehydration treatment, even if the substrate is dried at a relatively high temperature, the surface of the aluminum nitride film layer 200 does not react to form aluminum hydroxide, and the drying treatment can be performed at a temperature of, for example, 60 ℃ to 90 ℃. Therefore, the drying process of the substrate can be accelerated, the hydrophilic organic solvent on the substrate can be volatilized completely in the drying process, and the organic solvent is prevented from remaining on the substrate.

It should be noted that, in the present embodiment, the drying process is performed directly after the dehydration process is performed, that is, no additional wet process is performed between the dehydration process and the drying process. In addition, the acid cleaning process before the dehydration treatment is performed after the wet process, and the dehydration treatment is directly performed in a short time after the acid cleaning, that is, no additional wet process is performed between the acid cleaning and the dehydration treatment.

In the above processing process, the wet process can be used to complete the wet etching process, for example, and can remove residues, contaminants, particles, etc. on the surface of the substrate (including the surface of the aluminum nitride film), and the aluminum hydroxide generated on the surface of the aluminum nitride film in the previous wet process can be prevented by the weak acid treatment, so that the generated aluminum hydroxide can be removed, and then the dehydration treatment is used to remove the moisture on the aluminum nitride film, thereby avoiding the chemical reaction between the residual moisture and the aluminum nitride, stabilizing the surface of the aluminum nitride layer without generating impurities in the subsequent drying process, and the hydrophilic organic solvent is easily removed directly by volatilization in the drying process.

Therefore, when other films are formed on the aluminum nitride film, it is advantageous to provide flatness of the subsequently formed film 300 and improve adhesion between the formed film 300 and the aluminum nitride film 200. For example, in the manufacturing method of the filter, a metal layer is usually formed on an aluminum nitride film layer to form the top electrode.

Specifically, the method of manufacturing the filter generally includes: a bottom electrode, an aluminum nitride piezoelectric layer, and a top electrode are sequentially formed on a substrate. And after forming the aluminum nitride piezoelectric layer, before preparing the top electrode, comprising: performing a wet process (e.g., wet cleaning) on the substrate, and performing dehydration treatment by using a hydrophilic organic solvent after the wet process to remove moisture on the surface of the aluminum nitride piezoelectric layer; and then, drying the base material, wherein the hydrophilic organic solvent is volatilized in the drying process.

The specific methods of the dehydration and the drying can refer to the above embodiments, and are not described herein again. In addition, the wet process and the dehydration treatment can also include the step of pickling the substrate to remove aluminum hydroxide impurities formed on the surface of the aluminum nitride piezoelectric layer. Further, the dehydration treatment may be performed within 30 seconds after the acid washing. Alternatively, in the case of no acid washing, the dehydration treatment is performed within 30 seconds after the wet process.

According to the preparation method of the filter, the surface cleanliness and the flatness of the aluminum nitride piezoelectric layer can be improved, so that the film quality of the subsequently formed top electrode is improved, the adhesion between the top electrode and the aluminum nitride piezoelectric layer is improved, and the device performance of the formed filter is guaranteed.

It should be noted that, although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the embodiments. It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the protection scope of the technical solution of the present invention, unless the content of the technical solution of the present invention is departed from.

It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. It must be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to "a step" or "an apparatus" means a reference to one or more steps or apparatuses and may include sub-steps as well as sub-apparatuses. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or" rather than the definition of a logical "exclusive or" unless the context clearly dictates otherwise. Further, implementation of the methods and/or apparatus of embodiments of the present invention may include performing the selected task manually, automatically, or in combination.