Wet etching method for preventing plateau

Abstract

Disclosed is a wet etching method for preventing a plateau. According to an embodiment of the present invention, the wet etching method comprises the steps of: forming an etching pattern on a central area of an etching target area of an etching target by using a first mask defining the central area of the etching target area; and performing wet etching on the etching target area by using a second mask defining the etching target area.

Description

Wet etching method to prevent plateau

[0001] The examples below describe wet etching methods that prevent plateau formation.

[0002] The most common techniques for manufacturing membranes utilize photolithography and wet etching. These techniques involve lithography to create a pattern for the desired membrane area, then selectively removing the area using wet etching.

[0003] However, in the final stage of the etching process for membrane production, a plateau may occur due to stress concentration and etching unevenness, which may result in a decrease in the production yield and thickness uniformity of the final product.

[0004] These shortcomings can cause problems such as decreased productivity and quality, and therefore, technologies need to be proposed to address these shortcomings and problems.

[0005] In order to solve the problems of reduced productivity and quality, a wet etching method for preventing plateau is proposed.

[0006] However, the technical problems to be solved by the present invention are not limited to the above problems, and can be expanded in various ways without departing from the technical spirit and scope of the present invention.

[0007] According to one embodiment, a wet etching method may include a step of forming an etching pattern in a central area of ​​an etching target area of ​​an etching object using a first mask defining a central area of ​​the etching target area; and a step of performing wet etching on the etching target area using a second mask defining the etching target area.

[0008] According to one aspect, the first mask may be characterized in that it is disposed in an edge region excluding the central region, which is determined based on the position and area of ​​a plateau that occurs when wet etching is performed on the etching target object in which only the second mask is disposed in the etching target region.

[0009] According to another aspect, the etching pattern may be characterized in that it is used for the purpose of increasing the etching speed in the central region of the etching target region during the wet etching process.

[0010] According to another aspect, the step of forming the etching pattern and the step of performing the wet etching may be characterized in that they are performed as a single process.

[0011] According to another aspect, the step of forming the etching pattern and the step of performing the wet etching may be characterized in that they are each performed as sequential processes.

[0012] According to one embodiment, a mask structure used for wet etching may include a first mask defining a central region on an etching target region of an etching object and used to form an etching pattern in the central region; and a second mask defining the etching target region and used to perform wet etching on the etching target region.

[0013] According to one aspect, the first mask may be characterized in that it is disposed in an edge region excluding the central region, which is determined based on the position and area of ​​a plateau that occurs when wet etching is performed on the etching target object in which only the second mask is disposed in the etching target region.

[0014] According to another aspect, the etching pattern may be characterized in that it is used for the purpose of increasing the etching speed in the central region of the etching target region during the wet etching process.

[0015] According to another aspect, the first mask and the second mask may be characterized in that they are used in a process of forming the etching pattern and a process of performing the wet etching are performed as a single process.

[0016] According to another aspect, the first mask and the second mask may be characterized in that they are used for each process when the process of forming the etching pattern and the process of performing the wet etching are performed as sequential processes.

[0017] According to another embodiment, a wet etching method may include the steps of performing a surface treatment to increase surface roughness in a central region on an etching target region of an etching object; and performing wet etching on the etching target region using a mask defining the etching target region.

[0018] According to one aspect, the step of performing the surface treatment may be characterized as a step of performing the surface treatment on the central region determined based on the position and area of ​​a plateau that occurs when wet etching is performed on the etching target object on which only the mask is placed without the surface treatment in the etching target area.

[0019] According to another aspect, the step of performing the wet etching may be characterized as a step of performing wet etching on the etching target area while increasing the etching speed in the central area where the surface roughness is increased through the surface treatment.

[0020] According to another aspect, the step of performing the surface treatment may be a step of performing a surface treatment that increases surface roughness in the central region by using an additional mask defining the central region.

[0021] One embodiment proposes a wet etching method that prevents plateaus, thereby achieving a technical effect that resolves the problems of reduced production yield and thickness uniformity of final products, and reduced productivity and quality.

[0022] However, the effects of the present invention are not limited to the above effects, and can be expanded in various ways without departing from the technical spirit and scope of the present invention.

[0023] FIG. 1 is a flow chart illustrating a wet etching method according to one embodiment.

[0024] Figures 2a to 2h are plan views illustrating a wet etching method according to one embodiment.

[0025] Figures 3a to 3e are cross-sectional views illustrating a wet etching method according to one embodiment.

[0026] Figure 4 is a flow chart illustrating a wet etching method according to another embodiment.

[0027] Figures 5a to 5c are plan views illustrating a wet etching method according to one embodiment.

[0028] Figures 6a to 6c are cross-sectional views illustrating a wet etching method according to one embodiment.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited or restricted by these embodiments. In addition, the same reference numerals in each drawing represent the same components.

[0030] In addition, the terminology used in this specification is a term used to appropriately express the preferred embodiments of the present invention, and this may vary depending on the intention of the viewer or operator, or the customs of the field to which the present invention belongs. Therefore, the definition of these terms should be determined based on the contents of this specification. For example, in this specification, the singular also includes the plural unless specifically stated in the phrase. In addition, the terms "comprises" and / or "comprising" as used in this specification do not exclude the presence or addition of one or more other components, steps, operations, and / or elements. In addition, although the terms first, second, etc. are used in this specification to describe various regions, directions, shapes, etc., these regions, directions, and shapes should not be limited by these terms. These terms are only used to distinguish a certain region, direction, or shape from another region, direction, or shape. Therefore, a part referred to as a first part in one embodiment may be referred to as a second part in another embodiment.

[0031] It should also be understood that the various embodiments of the present invention, while different, are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Furthermore, it should be understood that the location, arrangement, or configuration of individual components within each of the disclosed embodiments may be modified without departing from the spirit and scope of the present invention.

[0032] Hereinafter, a wet etching method and a mask structure used therein according to embodiments will be described in detail with reference to the drawings.

[0033]

[0034] FIG. 1 is a flow chart illustrating a wet etching method according to one embodiment, FIGS. 2a to 2h are plan views illustrating a wet etching method according to one embodiment, and FIGS. 3a to 3e are cross-sectional views illustrating a wet etching method according to one embodiment.

[0035] The wet etching method described below is assumed to be performed by an automated and mechanized wet etching system.

[0036] According to one embodiment, a wet etching method performs wet etching on an etching target area using only a mask (hereinafter, referred to as a second mask (MASK2)) defining an etching target area of ​​an etching object (Target), and then forms an etching pattern (Etch pattern) in a central area of ​​the etching target area using a mask (hereinafter, referred to as a first mask (MASK1)) defining a central area (Central area) of the etching target area, and then performs wet etching on the etching target area using the second mask, thereby increasing an etching speed in the central area through the etching pattern formed in the central area of ​​the etching target area more than an etching speed in an edge area excluding the central area of ​​the etching target area, thereby uniformly etching the etching speed over the entire etching target area, thereby preventing a plateau.

[0037] More specifically, in step (S110), the wet etching system can place a second mask on one surface of the etching target object, excluding the etching target area, to define the etching target area as shown in FIGS. 2A and 3A.

[0038] Next, in step (S120), the wet etching system may place a first mask on the edge region of the etching target region (the remaining region of the etching target region excluding the central region) based on the central region, in order to define a central region on the etching target region as illustrated in FIGS. 2b and 3b.

[0039] Here, the first mask may be placed in the remaining edge area excluding the central area determined based on the position and area of ​​the plateau (hereinafter, the position and area of ​​the plateau refers to the position and area of ​​the plateau that is assumed to occur when wet etching is performed on an etching target on which only the second mask is placed).

[0040] For example, the first mask may be placed in an edge region excluding a central region corresponding to the position of the plateau, with the remaining area excluding an area corresponding to the area of ​​the plateau among the areas of the etching target region. For a more specific example, the first mask may be placed in an edge region including an area spaced 250 μm apart from the outer edge of the etching target region.

[0041] Since the etching target area has a larger area than the central area, the first mask defining the central area can be formed to cover at least a portion of the second mask defining the etching target area.

[0042] Therefore, in step (S120), the wet etching system can place the first mask in the remaining edge area excluding the central area determined based on the position and area of ​​the plateau in the etching target area.

[0043] For example, when the etching target is silicon and the etching solution used for wet etching is a hydroxide-based solution (e.g., TMAH, KOH, etc.), the first mask may be formed of a silicon-based material, Mo, Zr, or polymer-based material that has solubility in the hydroxide-based etching solution.

[0044] For reference, the etching solution used in wet etching may be an isotropic wet etching solution (e.g., HNA, etc.) as well as an anisotropic etching solution (e.g., hydroxide-based etching solution such as TMAH or KOH).

[0045] In the next step (S130), the wet etching system can form an etching pattern in the central region of the etching target region using the first mask, as shown in FIGS. 2c and 3c.

[0046] The shape of the etching pattern can be varied as shown in FIGS. 2d to 2g and FIGS. 3c to 3d, but is not limited thereto. For reference, FIG. 3c is a cross-sectional view for FIGS. 2c and 2e, and FIG. 3d is a cross-sectional view for FIGS. 2f and 2g.

[0047] Although not depicted as a separate step, after the etching pattern is formed in step (S130), the wet etching system can remove the first mask. However, without limitation or restriction thereto, the first mask may be formed to be automatically dissolved and removed simultaneously with the formation of the etching pattern in step (S130), so that the process of removing the first mask may be omitted.

[0048] In step (S140), the wet etching system can perform wet etching on the etching target area using the second mask as illustrated in FIGS. 2h and 3e. FIG. 3e illustrates an etching target with the second mask removed after wet etching is performed, and the shape and size of the remaining trapezoidal sidewalls after wet etching can be implemented in various ways depending on the degree of etching.

[0049] At this time, the etching pattern formed by the first mask can be used to increase the etching speed in the central region of the etching target area during wet etching compared to the etching speed in the edge region excluding the central region of the etching target area.

[0050] Accordingly, in step (S140), the wet etching system uses the etching pattern to increase the etching speed in the central region more than the etching speed in the edge region excluding the central region in the etching target region, thereby making the etching speed uniform throughout the etching target region and performing wet etching on the etching target region.

[0051] Although steps (S130) and (S140) are described as being performed as sequential processes, they are not limited thereto and steps (S130) and (S140) may be performed as a single process. That steps (S130) and (S140) are performed as a single process means that forming an etching pattern in step (S130) and performing wet etching on an etching target area in step (S140) are based on the same wet etching method.

[0052] In a wet etching method according to one embodiment, a mask structure used includes a first mask used to define a central region on an etching target region of an etching object as described above and to form an etching pattern in the central region, and a second mask used to define the etching target region and to perform wet etching on the etching target region (see FIGS. 2B and 3B), thereby increasing an etching speed in a central region of the etching target region in a wet etching process more than an etching speed in an edge region excluding the central region of the etching target region, thereby making the etching speed uniform throughout the etching target region, thereby preventing a plateau.

[0053] The forming of an etching pattern in a central region and the performing of wet etching on an etching target region can be performed as a single process or as sequential processes, respectively. The first mask and the second mask included in the mask structure can be used to perform the process of forming an etching pattern and the process of performing wet etching as a single process, or can be used for each process, respectively, to perform the process of forming an etching pattern and the process of performing wet etching as sequential processes.

[0054]

[0055] FIG. 4 is a flow chart illustrating a wet etching method according to another embodiment, FIGS. 5a to 5c are plan views illustrating a wet etching method according to one embodiment, and FIGS. 6a to 6c are cross-sectional views illustrating a wet etching method according to one embodiment.

[0056] The wet etching method described below is assumed to be performed by an automated and mechanized wet etching system.

[0057] According to another embodiment, a wet etching method performs a surface treatment to increase the surface roughness in a central area of ​​an etching target area of ​​an etching object (Target) more than an etching rate in an edge area excluding the central area of ​​the etching target area, and then performs wet etching on an etching target area including the surface-treated central area based on a mask defining the etching target area, thereby increasing the etching rate in the central area where the surface roughness has increased through the surface treatment more than an etching rate in an edge area excluding the central area of ​​the etching target area, thereby uniformly etching the etching rate throughout the etching target area, thereby preventing a plateau.

[0058] More specifically, in step (S410), the wet etching system can perform surface treatment to increase surface roughness in a central region on an etching target region of the etching target object, as illustrated in FIGS. 5A and 6A.

[0059] More specifically, the wet etching system can perform surface treatment on a central region determined based on the position and area of ​​the plateau (hereinafter, the position and area of ​​the plateau refers to the position and area of ​​the plateau that is assumed to occur when wet etching is performed on an etching target object on which only a mask is placed without surface treatment in the etching target area).

[0060] For example, a wet etching system may perform surface treatment on a central region corresponding to a position of a plateau, with an area corresponding to the area of ​​a plateau among the areas of the etching target region. For a more specific example, the wet etching system may perform surface treatment on a central region, which is an area excluding an edge region including an area spaced 250 μm from the outer edge of the etching target region among the areas of the etching target region.

[0061] Here, surface treatment of the central region can be performed using an additional mask defining the central region. For example, a wet etching system can perform surface treatment that increases surface roughness only for the exposed central region using an additional mask positioned on the edge region excluding the central region, which corresponds to the position of the plateau, with the remaining area of ​​the etching target region excluding the plateau area.

[0062] Next, in step (S420), the wet etching system can place a mask on one surface of the etching target object, excluding the etching target area, to define the etching target area as shown in FIGS. 5b and 6b.

[0063] In step (S430), the wet etching system may perform wet etching on the etching target area using a mask defining the etching target area as illustrated in FIGS. 5C and 6C. FIG. 6C illustrates an etching target object with the mask removed after wet etching is performed, and the shape and size of the remaining trapezoidal sidewalls after wet etching can be implemented in various ways depending on the degree of etching.

[0064] At this time, the etching speed in the central region where the surface roughness is increased through surface treatment can be increased compared to the etching speed in the edge region excluding the central region in the etching target region.

[0065] Therefore, in step (S430), the wet etching system can perform wet etching on the etching target area by increasing the etching speed in the central area where the surface roughness is increased through surface treatment more than the etching speed in the edge area excluding the central area in the etching target area, thereby making the etching speed uniform throughout the etching target area.

[0066]

[0067] Although the embodiments described above have been described by way of limited examples and drawings, those skilled in the art will appreciate that various modifications and variations can be made based on the above teachings. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0068] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. In the wet etching method, A step of forming an etching pattern in a central area of ​​an etching target area of ​​an etching target object using a first mask defining a central area of ​​the etching target area; and A step of performing wet etching on the etching target area using a second mask defining the etching target area. A wet etching method comprising:

2. In paragraph 1, The above first mask, A wet etching method characterized in that the second mask is placed in the edge area excluding the central area, which is determined based on the location and area of ​​the plateau that occurs when wet etching is performed on the etching target object in which only the second mask is placed in the etching target area.

3. In paragraph 1, The above etching pattern is, A wet etching method characterized in that it is used for the purpose of increasing the etching speed in the central region of the etching target region during the wet etching process.

4. In paragraph 1, The step of forming the above etching pattern and the step of performing the above wet etching are: A wet etching method characterized in that it is performed as a single process.

5. In paragraph 1, The step of forming the above etching pattern and the step of performing the above wet etching are: A wet etching method characterized in that each process is performed sequentially.

6. In the mask structure used for wet etching, A first mask defining a central region on an etching target area of ​​an etching target and used to form an etching pattern in the central region; and A second mask defining the etching target area and used to perform wet etching on the etching target area A mask structure including:

7. In paragraph 6, The above first mask, A mask structure characterized in that it is disposed in the edge region excluding the central region, which is determined based on the position and area of ​​the plateau that occurs when wet etching is performed on the etching target object in which only the second mask is disposed in the etching target region.

8. In paragraph 6, The above etching pattern is, A mask structure characterized in that it is used for the purpose of increasing the etching speed in the central region of the etching target region during the wet etching process.

9. In paragraph 6, The above first mask and the above second mask, A mask structure characterized in that the process of forming the above etching pattern and the process of performing the above wet etching are performed as a single process.

10. In paragraph 6, The above first mask and the above second mask, A mask structure characterized in that the process of forming the above etching pattern and the process of performing the above wet etching are performed as sequential processes, and each process is used separately.

11. In the wet etching method, A step of performing surface treatment to increase surface roughness in the central region of the etching target area of ​​the etching target; and A step of performing wet etching on the etching target area using a mask defining the etching target area. A wet etching method comprising:

12. In paragraph 11, The step of performing the above surface treatment is: A wet etching method characterized in that it is a step of performing surface treatment on the central area determined based on the position and area of ​​a plateau that occurs when wet etching is performed on the etching target object on which only the mask is placed without the surface treatment in the etching target area.

13. In paragraph 11, The step of performing the above wet etching is: A wet etching method characterized by a step of increasing the etching speed in the central region where the surface roughness is increased through the surface treatment and performing wet etching on the etching target region.

14. In paragraph 11, The step of performing the above surface treatment is: A wet etching method characterized by a step of performing surface treatment to increase surface roughness in the central region using an additional mask defining the central region.

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