KR100976864B1 - Method of processing hydrophobic surface using laser ablation and solid body having hydrophobic surface of dual scaled structure - Google Patents

Abstract

The present invention relates to a processing method using a laser, and more particularly to a surface processing method to have a super water-repellency by processing the surface of the object to be processed using laser ablation and to a solid substrate of the super water-repellent surface processed through the same will be.

In the super water-repellent surface processing method using the laser ablation according to the present invention, the surface of the solid substrate to be processed is moved along a plurality of first scan lines parallel to the first direction and spaced apart in a second direction crossing the first direction. A first processing step of continuously irradiating a laser beam onto the surface to perform a fusion process; And a second processing step of continuously irradiating a laser beam onto the surface of the solid substrate to be processed while moving along a plurality of second scan lines parallel to the second direction and spaced apart in the first direction. The first machining step and the second machining step are repeatedly performed along the first scan line and the second scan line.

Laser ablation, scan line, fusion, super water repellency, curved surface, roll processing

Description

Super water-repellent surface processing method using laser ablation and solid substrate of super water-repellent surface with dual scale microstructure

The present invention relates to a processing method using a laser, and more particularly, to a surface processing method to have a super water-repellency by processing the surface of the object to be processed using laser ablation and a solid substrate of the super water-repellent surface processed through the same will be.

Laser processing is the most common and stabilized process in high energy photoprocessing techniques using integrated photons. As is known, lasers have a shorter wavelength and have a higher instantaneous peak power, thereby enabling micromachining with little heat affected zone (HAZ) in the processed specimen.

Laser ablation processing refers to cutting a surface of a workpiece by irradiating the workpiece with a short pulsed laser beam. In the ablation processing using such a short pulse laser beam, the heat affected portion of the processing portion is overwhelmingly small compared to the processing by a continuous oscillation laser or a normal pulse laser, and thus the microfabrication with high precision is possible. In addition, micromachining using laser has the property that the laser beam can focus from several micrometers to hundreds of micrometers through optical parts such as lenses and mirrors, so it is easy to switch the focus size through the selection of the appropriate lens. have.

In general, when the laser ablation method is applied to fabricate a large-area conical or spherical microstructure, as shown in FIG. Divided into stages, the area is gradually enlarged, leaving the desired workpiece and removing the surroundings.

Referring to FIG. 15, in order to form the protrusion 155 on the object 150, all of the first layer is removed (FIG. 15A), and the second layer leaves only a portion corresponding to the vertex of the cone. The remaining portion is removed to form the vertex portion of the cone (FIG. 15 (b)), while the third layer removes the remaining portion leaving a wider portion than the second layer to form the lower portion of the cone's vertex (FIG. 15). (c)). And while gradually increasing the portion remaining in the lower layer to complete the cone shape (Fig. 15 (d) and (e)).

As described above, the conventional processes have to be processed based on different drawings for each layer, which takes a long time and requires complicated processing such as aligning the processing shapes of the layers. In addition, when a laser having a processing spot diameter of 10 μm is used, a horizontal layer of at least several μm is inevitably formed on the slope of the cone. Therefore, at least the diameter of the bottom surface must be 100 μm or more in order to form a cone. there was.

The present invention has been made on the basis of the technical background as described above, and its object is to simply and easily perform a plurality of aligned cones, truncated cones, or hemispherical protrusions by repeatedly performing laser ablation processing along a lattice processing pattern. It is to provide a super water-repellent surface processing method that can be formed on the surface of the workpiece.

Another object of the present invention is to perform a laser ablation process with a lattice processing pattern along a three-dimensional curved surface or a roll surface, thereby making it possible to form fine protrusions on the three-dimensional curved or roll surface, which is impossible in a semiconductor process. It is to provide a processing method.

Still another object of the present invention is to provide a solid substrate having a dual-scale super water-repellent surface by simultaneously forming the micro-scale irregularities and nano-scale protrusions of the lattice pattern through laser ablation processing.

In the super water-repellent surface processing method using the laser ablation according to an embodiment of the present invention, while moving along a plurality of first scan lines parallel to each other in a second direction crossing the first direction and parallel to the first direction. A first processing step of continuously irradiating a laser beam onto the surface of the solid substrate to be processed to ablation the ablation process; And a second processing step of continuously irradiating a laser beam onto the surface of the solid substrate to be processed while moving along a plurality of second scan lines parallel to the second direction and spaced apart from each other in the first direction. . The first machining step and the second machining step are repeatedly performed along the first scan line and the second scan line.

The method may further include setting the first scan line and the second scan line on the object solid substrate.

In the first processing step or the second processing step, the laser beam may be fixed, and the workpiece may be processed by moving the solid substrate.

The plurality of first scan lines and the second scan lines may be orthogonal to each other to form a lattice-shaped processing pattern on the surface of the solid substrate to be processed.

In addition, in the first machining step or the second machining step, the plurality of first scan lines or the second scan lines may be sequentially processed, and the plurality of first scan lines or the second scan lines may be simultaneously processed. It is also possible. The first machining step and the second machining step may be alternately performed repeatedly.

Super water-repellent surface processing method using a laser ablation according to another embodiment of the present invention, measuring the surface data of the three-dimensional curved surface of the solid substrate to be processed; Calculating a dynamic focus using the measured surface data; And a laser processing step of performing laser processing by interlocking the calculation result of the dynamic focus and the galvano scanner.

In this case, the laser processing step, the laser beam is moved along the plurality of first scan lines parallel to the first direction and spaced apart from each other in a second direction crossing the first direction, the laser on the three-dimensional curved surface of the solid substrate to be processed A first processing step of continuously irradiating the beam with the beam; And a second processing step of continuously irradiating a laser beam onto the three-dimensional curved surface of the solid object to be processed while moving along a plurality of second scan lines parallel to the second direction and spaced apart from each other in the first direction. It includes, and repeats the first machining step and the second machining step along the first scan line and the second scan line.

The super water-repellent surface processing method using the laser ablation according to another embodiment of the present invention, in the method for processing the surface of the object roll (roll), parallel to the circumferential direction of the object roll, the object roll A first processing step of continuously irradiating a laser beam onto the surface of the roll to be processed while moving along a plurality of first scan lines spaced apart from each other in an axial direction of a fusion process; And a second machining step parallel to the axial direction of the roll and continuously blasted by irradiating a laser beam onto the surface of the roll to be processed while moving along a plurality of second scan lines spaced apart from each other in the circumferential direction of the roll. The first machining step and the second machining step are repeatedly performed along the first scan line and the second scan line.

When the processing spot diameter of the laser beam is d and the distance between the plurality of adjacent first scan lines is p, it is preferable to satisfy the condition of 0.2 ≦ p / d ≦ 4.

On the other hand, the solid substrate of the super water-repellent surface having a dual-scale microstructure according to the present invention is a microstructure in which the protrusions and depressions of the micro-scale are continuously arranged in a lattice pattern; And a nanostructure in which nanoscale protrusions are formed on the surface of the protrusion of the microstructure.

The microstructures and nanostructures may be formed by a surface processing method using laser ablation.

The depressions of the microstructures are formed between adjacent protrusions, and as the depth deepens, the inclination gradually increases.

As described above, according to the super water-repellent surface processing method using the laser ablation according to the present invention, a plurality of aligned cones, truncated cones, or hemispherical protrusions are simply and easily carried out by performing laser fusion processing a plurality of times along a scan line. Can be formed.

In addition, the surface may be formed to have super water repellency by forming a nano-scale protrusion together with the micro-scale irregularities on the surface of the solid substrate to be processed.

In the surface processing method using the laser ablation according to the present invention, the super water-repellent surface may be processed by forming fine protrusions arranged in a lattice pattern on the surface of the roll as well as the three-dimensional curved surface, which is impossible with the semiconductor process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like elements throughout the specification.

1 is a configuration diagram of a laser processing system capable of performing the surface processing method according to the first embodiment of the present invention.

The laser processing system 100 includes a first reflecting apparatus 10 for adjusting an angle by reflecting a laser beam L emitted from a light source (not shown) emitting a laser beam L in a lateral direction, and the first reflector. And a second reflector 20 positioned at one side of the reflector 10 at a predetermined distance to reflect the laser beam L reflected by the first reflector 10 in a vertical direction. The lens 30 may further include a lens 30 which focuses the laser beam L reflected by the second reflector 20 and irradiates the object 50.

The first reflector 10 and the second reflector 20 reflecting the laser beam L may be selected from one of a mirror, a stay lens, and an objective lens.

The overlapping range of the laser beam (L) irradiated to the object 50 can be adjusted according to the setting, the workpiece formed on the object 50 is processed spot 52 according to the profile of the laser beam (L) The shape of the may vary, and according to the change can form a cone, elliptical cone, polygonal pyramidal or hemispherical protrusion shape on the front.

2 is a flow chart of a super water-repellent surface processing method using laser ablation according to the first embodiment of the present invention. 3 is a Gaussian distribution diagram of a laser beam, and FIG. 4 is a superimposition pattern and laser intensity of a laser beam processing spot irradiated to adjacent scan lines in a super water-repellent surface processing method using a laser ablation according to a first embodiment of the present invention. It is a schematic diagram which shows distribution.

First, the first scan line V and the second scan line H, which form a lattice shape, are set on the object 50 (S1).

In this case, the processing region of the object 50 may be set, and the first scan line V and the second scan line may be obtained in consideration of the size of the processing region and characteristics of the laser beam to be used. The interval and number of (H) can be set.

In the present exemplary embodiment, the first scan line V and the second scan line H may be set to be perpendicular to each other to form a lattice-shaped processing pattern on the surface of the processing object 50. However, the present invention is not limited thereto.

As a material of the solid substrate to be processed 50, a metal, a synthetic resin, or the like may be selected and used. In particular, when the object 50 is a metal, NAX80 may be used as a mold material.

Next, a first step of performing ablation processing by irradiating a laser beam continuously to the surface of the object 50 while moving along the first scan line V is performed (S2).

In this case, the laser beam (L) is fixed and the processing can be performed while moving the stage supporting the object 50, the object 50 is fixed and the laser beam (L) can be processed while moving. Do.

The plurality of first scan lines V are arranged side by side in a first direction and spaced apart by a predetermined distance in a second direction crossing the first direction.

As shown in FIG. 3, since the intensity of the laser beam L has a Gaussian distribution, the central portion of the laser beam L has a large ablation volume and a small peripheral portion. By using the characteristics of the laser beam L, the processing spot of the laser beam L passing through the adjacent first scan line V when the laser fusion processing along the plurality of first scan lines V is appropriately overlapped. As a result, a protrusion, that is, a portion in which the laser fusion processing remains, can be formed between the first scan lines V. FIG.

When the diameter of the processing spot of the laser beam L is d, and the distance between the plurality of neighboring first scan lines V is p, a desired processing is performed by setting to satisfy the condition of Equation 1 below. A solid substrate having surface characteristics can be obtained.

0.2 ≤ p / d ≤ 4

That is, when d = 10 micrometers, it is preferable to process p in the range of 2-40 micrometers.

If p / d is less than 0.2, there is a problem in that the portions to be laser processed are excessively overlapped to form protrusions (spikes). If the beam mode of the laser is ideally perfect Gaussian, it is possible to form protrusions, but it is known that it is impossible to produce a perfect Gaussian beam that is physically ideal. If p / d is greater than 4, there is a problem in that the performance expected in the application area is not obtained. For example, when a super water-repellent surface is formed, super water-repellent properties do not appear when p / d exceeds 4 (d = 10 μm).

Next, while performing along the second scan line (H), a second step of performing a continuous ablation process by irradiating a laser beam on the surface of the object 50 is performed (S3).

In this case, the laser beam L may be fixed and the processing may be performed while moving the stage supporting the object 50, and the object 50 may be fixed and processed while the laser beam L is moved. It is possible.

The plurality of second scan lines H are arranged side by side in the second direction while being spaced apart by a predetermined distance in the first direction. Even when laser fusion is performed along the second scan line H, the machining step may be performed under the same conditions as when the laser scan is performed along the first scan line V. FIG.

5 is a perspective view showing a workpiece manufactured by the super water-repellent surface processing method using laser ablation according to an embodiment of the present invention.

A depression 52 is formed along the scan line, and a protrusion 55 is formed between the scan lines.

Next, the first step and the second step machining are repeatedly performed along the first scan line V and the second scan line H. (S4)

That is, by repeatedly performing laser fusion processing along the first scan line V and the second scan line H, the recess 52 becomes deeper and the protrusion 55 becomes gradually more distinct in shape. Since the shapes of the protrusions 55 and the depressions 52 vary slightly depending on the number of repetitions, the number of repetitions can be adjusted to obtain a desired shape.

FIG. 6 is a schematic diagram showing an enlarged view of the protrusions 55 and the depressions 52 of the workpiece formed by processing the surface of the workpiece.

The area around the protrusion 55 is not removed much during the repeated machining along the scan line, while the area around the recess 52 is multi-reflection. As the phenomenon in which the laser beam L incident vertically from the upper side is reflected back to the opposite slope of the recess 52 is repeated, the depth of the recess 52 may be deeply formed.

Meanwhile, in the first step processing or the second step processing, the plurality of first scan lines V or the second scan lines H may be sequentially processed, and at the same time, the plurality of first scan lines V may be processed. In addition, the second scan line H may be processed. Further, even when the first step machining and the second step machining are repeatedly performed, the first step machining and the second step machining may be repeated alternately, or the second step machining may be performed multiple times. Step machining may be performed a plurality of times.

The surface of the solid substrate, which is processed as described above, has a microstructure of dual scale and is super water repellent. The dual-scale microstructure includes microstructures in which micro-scale protrusions 55 and depressions 52 are continuously arranged in a lattice pattern, and nano-scale protrusions are formed on surfaces of the protrusions 55 of the micro-structures. Nanostructures that are formed.

The solid substrate having a dual-scale microstructure is processed along the first scan line V and the second scan line H using the laser ablation as described above, so that the recess 52 of the microstructure is formed. Is formed between adjacent protrusions 55, and as the depth thereof increases, the slope may be formed steeply.

On the other hand, Figure 7 is a flow chart of a super water-repellent surface processing method using a laser ablation according to a second embodiment of the present invention, Figure 8 is a schematic diagram showing this. According to the surface processing method according to the present embodiment, laser processing on a three-dimensional curved surface is possible.

First, surface data of the three-dimensional curved surface 150 is measured for three-dimensional curved processing. (ST1)

As a method of measuring surface data of the three-dimensional curved surface 150, a non-contact method and a contact method may be selectively used. The non-contact method is a method of obtaining a three-dimensional shape by using a beam reflected from a three-dimensional curved surface by using a light source such as a laser, and the contact method is a method of obtaining a three-dimensional curved shape by using a contact sensor.

Next, the measured surface data is input to the dynamic focus unit 125 to calculate a dynamic focus for generating a beam that is constantly focused at the height of each part of the three-dimensional curved surface 15. (ST2)

Next, the calculation result of the dynamic focus unit 125 and the galvano scanner 135 are interlocked to perform laser processing. (ST3)

The other surface processing method may be performed according to the same process as the surface processing method according to the first embodiment, thereby recessed with the projection of the micro-scale continuously arranged in a lattice pattern on the three-dimensional curved surface 150 An addition can be formed. Furthermore, as the nanoscale protrusions are formed on the surface of the protrusion of the microstructure in the processing, the three-dimensional curved surface 150 has a dual scale microstructure. It is impossible to process such a three-dimensional curved surface 150 through a surface processing method using a semiconductor process.

9 is a schematic diagram showing a super water-repellent surface processing method using a laser ablation according to a third embodiment of the present invention. According to the surface processing method according to the present embodiment, laser processing is possible along the roll surface.

Referring to FIG. 9, in the surface processing method according to the present embodiment, the laser 250 is connected to the printing roll processing apparatus 300, and the laser processing is performed along the roll surface while controlling them together through the driving software 230. can do.

The printing roll processing apparatus 300 mounts the roll 350, which is an object to be processed, between the fixed shaft 325 and the rotating shaft 327, and mounts the objective lens 315 to the precision stage 310 installed thereon. The pattern 356 is formed while irradiating the surface of the roll 350 with the laser beam L.

The objective lens 315 connected to the laser 250 may be transferred in the axial direction of the roll 350 by driving the precision stage 310. Accordingly, by rotating the roll 350, a pattern may be formed along the circumference of the surface of the roll 350, and a pattern may be formed along the axial direction on the surface of the roll 350 by transferring the objective lens 315. . The LM guide 340 may transfer the fixed shaft 325 of the printing roll processing apparatus 300 in the axial direction.

As described above, the laser processing may be performed in the same manner as the surface processing method according to the first embodiment while scanning along the circumferential scan line and the axial scan line, thereby lattice the surface of the roll 350. Micro-scale protrusions and depressions may be formed that form a pattern and are continuously arranged. Furthermore, as the nano-scale protrusions are formed on the surface of the protrusion of the microstructure in the process, the surface of the roll 350 has a dual-scale microstructure. It is impossible to process the surface of the roll 350 through the surface processing method using the semiconductor process.

Below, the processing example of the super water-repellent surface processing is demonstrated with a photograph.

Processing Example 1

The interval (p) of the scan line was set to 20 μm, and a 400 Khz 100 mW laser beam (working spot diameter (d): 10 μm) was scanned 50 times with NAX80 (mold material), and the super water-repellent surface was processed. A close-up photo of the is shown.

Processing Example 2

The interval (p) of the scan line was 10 μm, and a 400 Khz 100 mW laser beam (machining spot diameter (d): 10 μm) was scanned 30 times with NAX80 (mold material), and the super water-repellent surface was processed. A close-up photo of the is shown.

Processing Example 3

The spacing (p) of the scan line was 10 μm, and a 400 Khz 50 mW laser beam (working spot diameter (d): 10 μm) was scanned 50 times with NAX80 (mold material), and the super water-repellent surface was processed. A close-up photo of the is shown.

Fig. 13A shows the contact state of water droplets on the surface of PDMS without surface treatment, and Figs. 13B to 13D show PDMS transferred by injection molding from NAX80 mold material which has been subjected to the surface treatment of machining examples 1 to 3, respectively. It shows the contact state of water droplets on the surface of (polydimethylsiloxane).

Although the contact angle (angle formed between the surface of the solid base material and the water droplets) is large when the surface is not processed, it can be confirmed that the surface after the surface processing according to each processing example is super water-repellent with an acute angle.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention. And it goes without saying that they belong to the scope of the present invention.

1 is a configuration diagram of a laser processing system capable of performing the surface processing method according to the first embodiment of the present invention.

2 is a flow chart of a super water-repellent surface processing method using laser ablation according to the first embodiment of the present invention.

3 is a Gaussian distribution diagram of a laser beam.

4 is a schematic diagram showing the overlap pattern and the laser intensity distribution of the laser beam processing spot irradiated to adjacent scan lines in the super water-repellent surface processing method using the laser ablation according to the first embodiment of the present invention.

5 is a perspective view showing a solid substrate manufactured by the super water-repellent surface processing method using the laser ablation according to the first embodiment of the present invention.

6 is a schematic diagram showing an enlarged view of protrusions and depressions of a workpiece formed by machining a surface of a workpiece.

7 is a flow chart of a super water-repellent surface processing method using a laser ablation according to a second embodiment of the present invention.

8 is a schematic diagram showing a super water-repellent surface processing method using a laser ablation according to a second embodiment of the present invention.

9 is a schematic diagram showing a super water-repellent surface processing method using a laser ablation according to a third embodiment of the present invention.

10 is an enlarged photograph of a surface structure subjected to laser fusion processing under the conditions according to Example 1 of the present invention.

11 is an enlarged photograph of a surface structure subjected to laser fusion processing under the conditions according to Example 2 of the present invention.

12 is an enlarged photograph of a surface structure subjected to laser fusion processing under the conditions according to Example 3 of the present invention.

Figure 13a is a photograph showing the contact state of the water droplets on the surface of the PDMS not surface-processed, Figures 13b to 13d are the water droplets on the surface of the PDMS transferred from the mold material subjected to the surface treatment of Examples 1 to 3, respectively The photo shows the contact state of.

14 is a perspective view showing a processing state according to the conventional laser processing method.

15 (a) to (e) is a process diagram showing a process of manufacturing a conical or hemispherical structure in accordance with a conventional laser processing method.

* Description of the symbols for the main parts of the drawings *

10: first reflector 20: second reflector

30: lens 50, 150: workpiece

52: depression 55, 155: protrusion

125: dynamic focus unit 135: galvano scanner

155: three-dimensional surface 230: driving software

250: laser 300: printing roll processing apparatus

310: precision stage 315: objective lens

320: printing roll 325: fixed shaft

327: axis of rotation 340: LM guide

350: roll 356: pattern

L: laser beam V: first scan line

H: second scan line

Claims (14)

Moving along a plurality of first scan lines parallel to the first direction and spaced apart from each other in a second direction crossing the first direction, the laser beam is continuously irradiated onto the surface of the solid substrate to be processed and ablation is performed. A) first processing step of processing; And A second processing step of continuously irradiating a laser beam onto the surface of the solid substrate to be processed while moving along a plurality of second scan lines parallel to the second direction and spaced apart from each other in the first direction Including, Repeating the first machining step and the second machining step along the first scan line and the second scan line; When the processing spot diameter of the laser beam is d, and the distance between the plurality of neighboring first scan lines or the plurality of neighboring plurality of second scan lines is p, 0.2 ≤ p / d ≤ 4 Super water-repellent surface processing method using laser ablation, characterized in that to satisfy the conditions of. The method of claim 1, In the first processing step or the second processing step, the super water-repellent surface processing method using the laser ablation, characterized in that for processing by fixing the laser beam and moving the object solid substrate. The method of claim 1, In the first processing step or the second processing step, a super water-repellent surface processing method using a laser ablation, characterized in that for processing a plurality of the first scan line or a second scan line sequentially. The method of claim 1, The super water-repellent surface processing method using laser ablation, characterized in that the first and second processing steps are alternately repeated. delete Measuring surface data of the three-dimensional curved surface of the object to be processed; Calculating a dynamic focus using the measured surface data; And And a laser processing step of performing laser processing by interlocking the calculation result of the dynamic focus with a galvano scanner, The laser processing step, In the first direction, while moving along a plurality of first scan lines spaced apart from each other in a second direction crossing the first direction and continuously irradiated with a laser beam to the three-dimensional curved surface of the solid substrate to be processed First processing step; And A second processing step of continuously irradiating a laser beam onto a three-dimensional curved surface of the solid object to be processed while moving along a plurality of second scan lines parallel to the second direction and spaced apart from each other in the first direction; Include, The super water-repellent surface processing method using laser ablation which repeats the first processing step and the second processing step along the first scan line and the second scan line. The method of claim 6, The super water-repellent surface processing method using the laser ablation further comprising the step of setting the first scan line and the second scan line on the object to be processed. The method of claim 6, When the processing spot diameter of the laser beam is d, and the distance between the plurality of neighboring first scan lines or the plurality of neighboring plurality of second scan lines is p, 0.2 ≤ p / d ≤ 4 Super water-repellent surface processing method using laser ablation, characterized in that to satisfy the conditions of. In the method of processing the surface of the object roll (roll), The first processing is parallel to the circumferential direction of the object roll, the first processing to continuously irradiate a laser beam to the surface of the object roll while blasting while moving along a plurality of first scan lines spaced apart from each other in the axial direction of the object roll step; And A second processing step of continuously irradiating a laser beam onto the surface of the roll to be processed while moving along a plurality of second scan lines that are parallel to each other in the axial direction of the roll and spaced apart from each other; Including, Repeating the first machining step and the second machining step along the first scan line and the second scan line; When the processing spot diameter of the laser beam is d, and the distance between the plurality of neighboring first scan lines or the plurality of neighboring plurality of second scan lines is p, 0.2 ≤ p / d ≤ 4 Super water-repellent surface processing method using laser ablation, characterized in that to satisfy the conditions of. The method of claim 9, The super water-repellent surface processing method using a laser ablation further comprising the step of setting the first scan line and the second scan line on the surface of the object to be processed. delete A micro structure in which protrusions and concave portions of the micro scale are continuously arranged in a lattice pattern; And Nanostructures are formed nano-scale projections on the surface of the protrusion of the microstructure Including, The concave portion of the microstructure is formed between adjacent protrusions, and the deeper the substrate of the super water-repellent surface having a dual-scale microstructure, characterized in that the inclined gradually formed as the depth deeper. 13. The method of claim 12, The microstructure and the nanostructure is a solid substrate of a super water-repellent surface having a dual-scale microstructure, characterized in that formed by the surface processing method using laser ablation. delete

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