Method for improving metal wet etching process

Abstract

The invention discloses a method for improving a wet etching metal process, and relates to the technical field of a semiconductor manufacturing process, and the method comprises the steps: forming a to-be-etched film layer on a substrate; a photoresist mask pattern is formed on the film layer to be corroded, and the photoresist mask pattern comprises an incompletely modified photoresist film layer located on the edge of the photoresist mask pattern; the incompletely modified photoresist film layer is removed; patterning the film layer to be corroded by adopting a wet etching process; and removing the photoresist mask pattern. According to the method for improving the wet etching metal process, the problem that residues are easily generated on the surface of a device in the existing wet etching metal process can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing processes, and more particularly, to a method for improving the wet etching process of metals. Background Art

[0002] In the field of chip preparation, the wet process is an indispensable processing method. The wet process mainly achieves the removal of materials through chemical dissolution. Wet etching not only has lower equipment and processing costs, but also causes minimal damage to non-etched materials, enabling a smoother surface topography to be created. In the removal of metal materials, the wet process also plays an important role. Compared with the dry process for removing the film layer to be etched, the wet process has a higher removal efficiency, meeting the needs of manufacturers for high-efficiency production.

[0003] As Figure 1 shown, taking the partial process of using the wet process to remove metallic aluminum as an example, in the prior art, it is usually necessary to prepare a patterned photoresist mask on the surface of the aluminum layer, and then through a series of processes such as baking, wet etching, wet cleaning, dry photoresist stripping, and cleaning to achieve the patterning of the metallic aluminum layer. However, in this process, due to the differences in the types of photoresist and developer, as well as the different aluminum etching solutions, white residual substances are often found attached to the surface of the device during topography inspection. Conventional methods such as over-etching with acidic and alkaline solutions and deionized water cleaning are difficult to remove these stubborn residues. Due to the obstruction of this part of the residue, the subsequent gap etching of some patterns cannot be completed, resulting in non-designed connection structures. And because the residue cannot be removed, it is found in the tests after device preparation that it has a great negative impact on the device performance, resulting in a very low product yield. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for improving the wet etching process of metals, which can solve the problem that residues are easily generated on the surface of devices in the existing wet etching process of metals.

[0005] The embodiments of the present invention are implemented as follows: The embodiments of the present invention provide a method for improving the wet etching process of metals, the method comprising: forming a film layer to be etched on a substrate; forming a photoresist mask pattern on the film layer to be etched, wherein the photoresist mask pattern includes an incompletely modified photoresist film layer located at the edge of the photoresist mask pattern; removing the incompletely modified photoresist film layer; patterning the film layer to be etched by using a wet etching process; removing the photoresist mask pattern.

[0006] In an alternative embodiment, removing the incompletely modified photoresist film layer includes: Removing the incompletely modified photoresist film layer by using a plasma cleaning process or a plasma etching process.

[0007] In an alternative embodiment, the processing gas used in the plasma cleaning process or the plasma etching process is any one or a combination of two or more of nitrogen, argon, oxygen, chlorine, boron trichloride, and carbon tetrafluoride.

[0008] In an alternative embodiment, the processing power of the plasma cleaning process or the plasma etching process is 50W - 150W, the processing duration is 5s - 20s, and the processing temperature is 20°C - 40°C.

[0009] In an alternative embodiment, removing the photoresist mask pattern includes: Removing the photoresist mask pattern by using a dry stripping process.

[0010] In an alternative embodiment, before or after removing the incompletely modified photoresist film layer, the method further includes: Baking the photoresist mask pattern.

[0011] In an alternative embodiment, the photoresist mask pattern has a hollowed-out portion, and the incompletely modified photoresist film layer is distributed along the edge of the hollowed-out portion.

[0012] In an alternative embodiment, the incompletely modified photoresist film layer dissolves hydroxide ions.

[0013] In an alternative embodiment, the film layer to be etched contains aluminum atoms or aluminum ions.

[0014] The beneficial effects of the embodiments of the present invention include: The method includes: forming a film layer to be etched on a substrate; forming a photoresist mask pattern on the film layer to be etched, wherein the photoresist mask pattern includes an incompletely modified photoresist film layer located at the edge of the photoresist mask pattern; removing the incompletely modified photoresist film layer; patterning the film layer to be etched by using a wet etching process; and removing the photoresist mask pattern. The method for improving the wet etching metal process provided by the present invention removes the incompletely modified photoresist film layer at the edge of the photoresist mask pattern by using a specific method after the photolithography process and before the wet etching process, effectively avoiding the complex reaction of acid - alkali - metal (such as aluminum) during the wet etching process, thereby avoiding the problem of stubborn compound residues on the surface of the film layer to be etched after wet etching, and further avoiding the occurrence of subsequent pattern gap etching inability and non - designed connection structures caused by residue blocking, reducing the negative impact on the device performance, and thus greatly improving the yield of the device. Brief Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following accompanying drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related accompanying drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic process flow diagram of preparing patterned aluminum metal by the existing wet etching metal process; Figure 2 It is a schematic process flow diagram of preparing patterned aluminum metal by a method for improving the wet etching metal process provided by an alternative solution of the present invention; Figure 3 It is a schematic process flow diagram of preparing patterned aluminum metal by a method for improving the wet etching metal process provided by another alternative solution of the present invention. Detailed Embodiments

[0017] The embodiments described below represent the information necessary for those skilled in the art to practice the embodiments and show the best mode of practicing the embodiments. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize the applications of these concepts not specifically presented herein. It should be understood that these concepts and applications are within the scope of the present disclosure and the appended claims.

[0018] It should be understood that when an element (such as a layer, region, or substrate) is referred to as "on another element" or "extending onto another element", it can be directly on another element or directly extend onto another element, or there may also be intervening elements. Similarly, it should be understood that when an element (such as a layer, region, or substrate) is referred to as "above another element" or "extending above another element", it can be directly above another element or directly extend above another element, or there may also be intervening elements.

[0019] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms as well. It should also be understood that when used herein, the term "comprising" indicates the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups of the above.

[0020] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should also be understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0021] In the existing wet etching process of metals, due to the differences in the types of photoresist and developer, as well as the different aluminum etching solutions, white residual substances will be generated on the surface of the device. It has been found that conventional methods such as over-etching with acidic and alkaline solutions and cleaning with deionized water cannot remove these residues, thus generating non-designed connection structures, which have a great negative impact on the device performance.

[0022] It can be seen from this that these residues are not metal residues, but a compound with acid and alkali corrosion resistance, which means that these residues are not left on the device surface due to insufficient wet etching of the metal. Therefore, in order to further characterize these residues, the present invention conducted the following experimental investigations: First, experimental wafer 1 with only photoresist coating but no exposure and development, experimental wafer 2 with only photoresist coating and development but no exposure, and experimental wafer 3 with normal photoresist coating, exposure, and development were respectively prepared, and a special pattern was designed for experimental wafer 3; second, the three experimental wafers were subjected to the existing wet etching process and their morphologies were inspected.

[0023] The experiment found that there were no white residues on the surfaces of experimental wafer 1 and experimental wafer 2, and there were white residues on the surface of experimental wafer 3, and the shape of the white residues was consistent with the special pattern designed during preparation. It can be seen from this that the generation of these residues is related to the lithography process and is mainly related to the photoresist after exposure and development.

[0024] To solve the above problems, please refer to Figure 2 and Figure 3 , the present invention provides a method for improving the wet etching process of metals, which can solve the problem that residues are easily generated on the surface of the device in the existing wet etching process of metals.

[0025] Specifically, as Figure 2 and Figure 3 shown, the present invention provides a method for improving the wet etching process of metals, which method comprises: Step 1: Form a film layer to be etched on a substrate; It should be noted that forming the film layer to be etched on the substrate is the starting step of the entire process. Building the film layer to be etched on the substrate material provides a basis for subsequent patterning. The substrate can be a single material film layer or a composite film layer made of composite materials. The type and thickness of the film layer to be etched can be determined according to specific process requirements. For example, in chip manufacturing, a metal film layer containing aluminum elements can be formed on the substrate.

[0026] Step 2: Form a photoresist mask pattern on the film layer to be etched, where the photoresist mask pattern includes an incompletely modified photoresist film layer located at the edge of the photoresist mask pattern; It should be noted that the photoresist is coated on the surface of the film layer to be etched. Through photolithography processes such as exposure and development, the designed pattern is transferred onto the photoresist to form a photoresist mask pattern. Due to the characteristics of the photoresist during the exposure and development processes, the photoresist in the edge region of the pattern will form an incompletely modified photoresist film layer. During the development of positive photoresist, the photoresist in the edge region of the pattern and the photoresist in the center region of the pattern receive different light intensities, resulting in partial underdevelopment and forming an incompletely modified photoresist film layer with properties different from those of the photoresist in the center region of the pattern.

[0027] The dissolution process of the developer on the photoresist can actually be subdivided into three steps: The first step is that the developer penetrates into the interior of the photoresist; the second step is that the developer breaks the connection bonds between the photoresist molecules; the third step is that the developer strips and takes away the separated components. Based on the above dissolution mechanism, it has been found that in the edge region of the pattern, the photoresist is in a special "semi-dissolved" shaped state. Although the photoresist in these edge regions still maintains a solid morphology, part of the developer remains inside. Due to the difference in the light intensity received by the photoresist in the edge region of the pattern and the photoresist in the center region of the pattern, the developer penetrating into the edge region cannot fully dissolve the photoresist. This incompletely dissolved state makes the edge region of the photoresist show strong alkalinity. In addition, compared with the unexposed photoresist, the removal rate of this part of the "semi-dissolved" photoresist is greatly increased when bombarded by plasma, resulting in a very high etching selectivity ratio with the normal photoresist.

[0028] Step 3: Remove the incompletely modified photoresist film layer; It should be noted that since the incompletely modified photoresist film layer has developer remaining inside, the incompletely modified photoresist film layer shows strong alkalinity. Therefore, it will cause abnormal reactions in the subsequent wet etching process. For this reason, before the wet etching process after the photolithography process, a specific method can be used to remove the incompletely modified photoresist film layer at the edge of the photoresist mask pattern to avoid its negative impact on the wet etching process.

[0029] Step 4: Pattern the film layer to be etched using a wet etching process; It should be noted that after removing the incompletely modified photoresist film layer, the film layer to be etched is processed by chemical dissolution using a wet etching process. According to the shape of the photoresist mask pattern, the unnecessary parts are dissolved and removed, and the required pattern is retained to achieve patterning of the film layer to be etched. For example, in chip manufacturing, a specific aluminum etching solution can be used to etch a metal film layer containing aluminum elements to form the required circuit pattern.

[0030] Step 5: Remove the photoresist mask pattern.

[0031] It should be noted that after patterning the film layer to be etched, the photoresist mask pattern can be removed using processes such as dry stripping to obtain the final metal patterned structure.

[0032] In the traditional process, the alkaline substances in the incompletely modified photoresist film layer can cause abnormal reactions during the wet etching process, generating precipitates such as aluminum hydroxide that are insoluble in acid and alkali solutions and forming residues on the device surface. However, in the method for improving the wet etching of metals provided by the present invention, before the wet etching process after the lithography process, a specific method is used to remove only the incompletely modified photoresist film layer at the edge of the photoresist mask pattern, effectively avoiding the complex acid-base-metal (such as aluminum) reaction during the wet etching process, thereby avoiding the problem of stubborn compound residues on the surface of the film layer to be etched after wet etching, and further improving the yield of the device.

[0033] In an alternative embodiment, Step 3: Removing the incompletely modified photoresist film layer includes: Step 31: Remove the incompletely modified photoresist film layer using a plasma cleaning process or a plasma etching process.

[0034] It should be noted that in the plasma cleaning process, the active particles in the plasma mainly undergo physical or chemical reactions with the incompletely modified photoresist film layer. In a plasma environment, the gas is ionized to generate a large number of active particles. When these particles come into contact with the incompletely modified photoresist film layer, they will break the chemical bonds of the photoresist molecules, decompose them into small molecule substances, and finally be pumped away in a gaseous form.

[0035] The plasma etching process is to use high-energy ions, free radicals, etc. in the plasma to physically sputter or chemically react with the material to remove the material in a plasma environment. When removing the incompletely modified photoresist film layer, the ions in the plasma are accelerated under the action of an electric field and bombard the surface of the incompletely modified photoresist film layer, sputtering the photoresist molecules from the surface. At the same time, the active substances in the plasma chemically react with the photoresist to form volatile products. For example, when using oxygen as the plasma gas, the oxygen free radicals in the oxygen plasma have strong oxidizing properties and can oxidize the organic components in the photoresist to form volatile substances such as carbon dioxide and water, thereby achieving the removal of the incompletely modified photoresist film layer.

[0036] The above-mentioned plasma cleaning process and plasma etching process both have high selective removal capabilities and can quickly and effectively remove the incompletely modified photoresist film layer. Compared with the traditional wet removal method, the plasma process is not limited by the solubility of the photoresist and can effectively remove some modified photoresists that are not easily dissolved in solvents, greatly improving the removal efficiency. Moreover, these two processes can precisely control the removal rate and degree by adjusting the parameters of the plasma (such as power, gas flow rate, pressure, etc.). When removing the incompletely modified photoresist film layer, only the modified part at the edge can be removed without affecting the normal photoresist pattern and the underlying film layer to be etched, ensuring the accuracy of the process and the integrity of the pattern.

[0037] In an alternative solution, the processing gas used in the plasma cleaning process or the plasma etching process is any one or a combination of two or more of nitrogen, argon, oxygen, chlorine, boron trichloride, and carbon tetrafluoride.

[0038] It should be noted that the above-mentioned plasma cleaning process and plasma etching process both utilize the physical or chemical interaction between the active particles (such as ions, electrons, free radicals, etc.) in the plasma and the material surface to achieve the treatment of the material surface. The processing gas is ionized in the plasma equipment to form a plasma, and the plasmas generated by different gases have different properties and functions. By using different gases or gas combinations, the requirements of various materials and processes can be met.

[0039] In an alternative solution, the processing power of the plasma cleaning process or the plasma etching process is 50W - 150W, the processing duration is 5s - 20s, and the processing temperature is 20°C - 40°C.

[0040] It should be noted that in the plasma cleaning process or the plasma etching process, the processing power refers to the amount of energy provided to generate the plasma. The power level affects the density and energy of the active particles (such as ions, electrons, free radicals, etc.) in the plasma. Processing with the power described in this solution can ensure the integrity of the photomask pattern while ensuring the removal of the incompletely modified photoresist film layer, without causing abnormalities in the pattern after etching. When the power is too low (e.g., less than 50 W), the number of generated active particles is extremely small and the energy is low, which may result in too low plasma energy and the inability to fully remove the incompletely modified photoresist film layer in a short time. When the power is too high (e.g., greater than 150 W), the number of active particles increases and the energy is enhanced, and the removal speed will increase, but it will cause excessive damage to the photoresist mask pattern and the underlying film layer to be etched.

[0041] The processing duration refers to the time when the plasma contacts and acts on the incompletely modified photoresist film layer. According to the processing time described in this case, it is possible to completely remove the incompletely modified photoresist film layer without damaging the photomask pattern. If the processing time is short (e.g., less than 5 s), it may not be completely removed. If the processing time is long (e.g., greater than 20 s), although the incompletely modified photoresist film layer can be removed more thoroughly, it may also increase the impact on the surrounding materials, such as changing the shape of the photomask pattern or causing certain erosion to the underlying film layer to be etched.

[0042] The processing temperature affects the chemical reaction rate between the plasma and the incompletely modified photoresist film layer. In the temperature range of 20°C to 40°C, the chemical reaction rate is relatively slow, but the removal rate of the incompletely modified photoresist film layer and the photomask pattern can be controlled more effectively, realizing the complete removal of the incompletely modified photoresist film layer while ensuring the integrity of the photomask pattern.

[0043] In an alternative solution, step 5: removing the photomask pattern includes: Step 51: Remove the photomask pattern using a dry stripping process.

[0044] It should be noted that the equipment and process chamber used in the dry stripping process are different from those in the plasma cleaning process and the plasma etching process. The dry stripping process uses reactive particles in the plasma to chemically react with the photoresist, specifically a process of decomposing the photoresist into volatile substances and removing them. During the dry stripping process, a wafer with a photoresist mask pattern is usually placed in the process chamber, and a specific gas (such as oxygen) is introduced. Under the action of an electric field, the gas is ionized to form a plasma. The oxygen ions fully undergo isotropic chemical reactions with the photoresist, decomposing it and reacting to form volatile substances (such as carbon dioxide, water, etc.), and then these volatile substances are discharged from the process chamber through the pumping system, thereby achieving the removal of the photoresist mask pattern.

[0045] In an alternative embodiment, step 3: before or after removing the incompletely modified photoresist film layer, the method further includes: Step 6: Bake the photoresist mask pattern.

[0046] It should be noted that, in an alternative embodiment, as Figure 3 shown, step 6: baking the photoresist mask pattern can be performed before step 3: removing the incompletely modified photoresist film layer. This can make the photoresist better cured, enhance the adhesion between the photoresist and the surface of the film layer to be etched, and at the same time make the solvent in the photoresist fully volatilize, avoiding the detachment of the photoresist mask pattern during the wet etching process. Under the action of high temperature, the polymer molecular chains inside the photoresist will undergo a certain degree of cross-linking to form a more stable structure.

[0047] In another alternative embodiment, as Figure 2 shown, step 6: baking the photoresist mask pattern can be performed after step 3: removing the incompletely modified photoresist film layer. At this time, the incompletely modified photoresist film layer has been removed. Baking can, on the one hand, further remove the moisture or other volatile substances remaining in the photoresist mask pattern during the manufacturing process, and on the other hand, cure the photoresist mask pattern to enhance its stability in the subsequent wet etching process, ensuring that the photoresist mask pattern can maintain its complete shape and accurately play a masking role during the wet etching process.

[0048] In an alternative embodiment, the photoresist mask pattern has a hollow portion, and an incompletely modified photoresist film layer is distributed along the edge of the hollow portion.

[0049] It should be noted that in the lithography process, the photoresist mask pattern is a key part for selectively etching the film layer to be etched. The photoresist mask pattern has hollow parts, which are hollow areas formed on the photoresist layer according to design requirements. During the lithography process, light passes through a specific pattern on the mask plate to expose the photoresist. After development, the photoresist in the exposed area (for positive photoresist) or the unexposed area (for negative photoresist) is removed, thus forming the hollow parts.

[0050] The incompletely modified photoresist film layer distributed along the edge of the hollow part is caused by the edge effect of the photoresist during the exposure and development processes. In the edge area of the photoresist, the light intensity and the action degree of the developer are different from those in the inner area of the photoresist (i.e., the aforementioned central area). For example, the intensity of the laser spot is weaker at the edge compared to the central area, resulting in different exposure degrees of the photoresist in the edge area from that in the inner area. Furthermore, the penetration and reaction speed of the developer at the edge are also different from those in the inner area. Within the same processing time, the degree of chemical and physical property changes of the photoresist in the edge area is different from that in the inner area, thus forming an incompletely modified photoresist film layer with different properties from the inner photoresist.

[0051] In an alternative solution, the photoresist mask pattern is a positive photoresist.

[0052] It should be noted that in the lithography process, photoresists are divided into positive photoresists and negative photoresists. When the photoresist mask pattern uses a positive photoresist, due to the characteristic of the positive photoresist that after being exposed to light, the photoactive compound (PAC) inside it undergoes a decomposition reaction, making the solubility of the photoresist in the exposed area greatly increase in the developer. When making the photoresist mask pattern, the positive photoresist is uniformly coated on the surface of the film layer to be etched, and is exposed through the mask plate. The photoresist area corresponding to the light-transmitting part on the mask plate is exposed to light, and the PAC decomposes. Subsequently, a development operation is carried out. The photoresist in the exposed area quickly dissolves in the developer and is removed, while the photoresist in the unexposed area remains, thus forming a photoresist mask pattern consistent with the mask plate pattern. For example, in the lithography link of chip manufacturing, the designed circuit pattern is made on the mask plate. After the positive photoresist is exposed and developed, it will replicate the corresponding pattern on the film layer to be etched on the chip surface, preparing for the subsequent patterning process of the film layer to be etched.

[0053] In an alternative solution, the incompletely modified photoresist film layer dissolves hydroxide ions.

[0054] It should be noted that during the development process of the photoresist, the developer will penetrate into the interior of the photoresist. When the photoresist mask pattern uses a positive photoresist, the developer is usually alkaline and contains hydroxide ions itself. In the edge region of the photolithographic pattern, due to the different light intensity from the central region, there are differences in the development process. The photoresist in the edge region may be in a "semi-dissolved" state, causing the hydroxide ions in the developer to be trapped in this part of the photoresist, resulting in the incomplete modified photoresist film layer dissolving hydroxide ions.

[0055] In an alternative solution, the film layer to be etched contains aluminum elements.

[0056] It should be noted that the film layer to be etched containing aluminum elements means that the film layer to be etched is mainly composed of aluminum elements. In an alternative solution, the film layer to be etched can exist in the form of metallic aluminum, with atoms bonded by metallic bonds, maintaining the characteristics of a metal, having good electrical conductivity, thermal conductivity, ductility, etc. In practical applications, such as in chip manufacturing, a metal film layer containing aluminum elements will be prepared on the substrate by physical vapor deposition, chemical vapor deposition, etc. for constructing circuit connection and other structures. Of course, in another alternative solution, the film layer to be etched can also be a compound containing aluminum elements, such as aluminum nitride (AlN), scandium aluminum nitride (AlScN). The above methods are also applicable to the wet etching process of compounds containing aluminum elements. Or, in another alternative solution, the film layer to be etched can also contain other metal elements. Those skilled in the art should be able to make reasonable selections and designs according to the actual situation, and no specific limitations are made here. The above methods are also applicable to the wet etching process of film layers to be etched containing other similar metal elements.

[0057] The above are only alternative solutions of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for improving the wet etching process of metals, characterized in that, The method includes: Forming a film layer to be etched on a substrate; Forming a photoresist mask pattern on the film layer to be etched, wherein the photoresist mask pattern includes an incompletely modified photoresist film layer located at the edge of the photoresist mask pattern; Removing the incompletely modified photoresist film layer; Patterning the film layer to be etched by a wet etching process; Removing the photoresist mask pattern.

2. The method for improving the wet etching metal process according to claim 1, characterized in that The removing of the incompletely modified photoresist film layer includes: Removing the incompletely modified photoresist film layer by a plasma cleaning process or a plasma etching process.

3. The method for improving the wet etching metal process according to claim 2, wherein The processing gas used in the plasma cleaning process or the plasma etching process is any one or a combination of two or more of nitrogen, argon, oxygen, chlorine, boron trichloride and carbon tetrafluoride.

4. The method for improving the wet etching metal process according to claim 2, characterized in that, The processing power of the plasma cleaning process or the plasma etching process is 50W - 150W, the processing duration is 5s - 20s, and the processing temperature is 20°C - 40°C.

5. The method for improving the wet etching metal process according to claim 1, characterized in that, The removing of the photoresist mask pattern includes: Removing the photoresist mask pattern by a dry stripping process.

6. The method for improving the wet etching of metal according to claim 1, characterized in that, Before or after the removing of the incompletely modified photoresist film layer, the method further includes: Baking the photoresist mask pattern.

7. The method for improving the wet etching metal process according to claim 1, characterized in that, The photoresist mask pattern has a hollow portion, and the incompletely modified photoresist film layer is distributed along the edge of the hollow portion.

8. The method for improving the wet etching metal process according to claim 1, characterized in that, The incompletely modified photoresist film layer dissolves hydroxide ions.

9. The method for improving the wet etching metal process according to claim 1, characterized in that, The film layer to be etched contains aluminum elements.

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