A method for preparing a small-size high-density microchannel

Abstract

The application relates to a preparation method of a small-size high-density microchannel, and relates to the technical field of microchannel enhanced phase change heat transfer. One of spin coating, screen printing or spraying is used to coat a photosensitive etching-resistant ink on the surface of a metal base to form a uniform and continuous photosensitive etching-resistant protective coating with a thickness of 0.2-10 microns; a microchannel mask pattern is engraved on the photosensitive etching-resistant protective coating by using a UV laser printer; the metal base with the microchannel mask pattern is soaked in an environment-friendly etching liquid for etching; the target metal base after etching is soaked in a stripping liquid capable of reacting with the photosensitive etching-resistant protective coating, so that the photosensitive etching-resistant protective coating strip is stripped from the surface of the target metal base, the microchannel wall is exposed, and a small-size high-density microchannel structure is obtained. The application has the advantages of accurate size control, good heat transfer performance, high efficiency, strong expansibility, and is especially suitable for the application field of heat dissipation such as enhanced boiling heat transfer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-channel enhanced phase change heat transfer, and particularly relates to a preparation method of a small-size high-density micro-channel for enhancing boiling heat transfer. BACKGROUND

[0002] Micro-channel is a typical and high-performance micro-scale heat and mass transfer enhancement structure, which can effectively enhance liquid transport and phase change heat transfer process, and is widely used in micro-fluidic, high heat flow cooling and electronic device thermal management fields. Especially with the development trend of high power, high integration and small size of advanced devices, the heat dissipation problem becomes increasingly serious, and the micro-channel enhanced boiling heat transfer technology is one of the best solutions, which has attracted great attention in recent years. Because the micro-channel structure can be prepared on the heat transfer surface, not only the heat transfer area can be increased, but also the bubble nucleation, growth and detachment can be promoted, and the liquid supply capacity of the surface can be improved by using the capillary wicking effect to inhibit the surface dryout phenomenon under high heat flux density, so that the heat transfer coefficient (HTC) and the critical heat flux density (CHF) of boiling can be greatly improved. The structure size, cross-sectional shape and channel density of the micro-channel have important influence on the boiling heat transfer performance, and the above structure characteristics and parameters are directly affected by the preparation method of the micro-channel. Therefore, optimizing the preparation method of the micro-channel has great significance for developing high-performance micro-channels and promoting their industrial application.

[0003] At present, in the application of enhanced boiling heat transfer, the micro-channel preparation methods mainly include mechanical machining, ultrafast laser ablation and 3D printing. Mechanical machining is the most traditional and common preparation method, and the engineering application is relatively mature, but the milling and wire cutting methods can only process larger micro-channels, and the minimum processing width of the channel and the channel wall (i.e. rib) is usually 0.3mm, which limits the increase of micro-channel capillary pressure and the increase of channel density, and the channel density is the number of channels per unit length in the vertical direction of the heat transfer surface, and the density of the mechanical machining micro-channel is usually less than 17cm -1, making it difficult to further improve the boiling heat transfer performance of microchannels. In addition, when microchannels are used in phase change heat dissipation devices such as ultra-thin heat pipes and temperature spreaders, it is difficult to process microchannels on their surfaces through mechanical processing because the thickness of their metal substrates is only 0.05-0.5mm. Ultrafast laser ablation refers to the use of femtosecond or picosecond laser systems to directly ablate microchannels on the heat transfer substrate. Its high processing accuracy is conducive to the preparation of small-sized and high-density microchannels, but the main problem is that it relies on expensive large-scale equipment and can only process one microchannel heat sink at a time. It also requires long-term scanning ablation to form high-performance microchannels with a large aspect ratio. Therefore, the processing efficiency is low and the cost is high. It is usually only suitable for laboratory research and some high-tech industries, and it is difficult to industrialize and mass-produce. If a relatively low-cost nanosecond laser system is used to directly ablate the microchannel, due to the easy generation of more obvious thermal effects, the etching effect of the metal microchannel will be poor, and problems such as thermal deformation of the substrate are prone to occur. 3D printing methods also require high equipment and operating skills, and there are problems such as step effects, insufficient processing precision, difficulty in preparing metal microchannels, and less than ideal structural strength. Therefore, existing technologies are difficult to achieve the simple, low-cost, efficient, high-precision, and highly scalable preparation of small-scale, high-density microchannels, which is not conducive to further improving the boiling heat transfer performance of microchannels and the engineering application of high-performance microchannel enhanced heat transfer structures. Summary of the Invention

[0004] The purpose of the present invention is to propose a method for preparing small-sized, high-density microchannels. The method proposed in the present invention does not require expensive large-scale professional equipment and a harsh experimental environment, and can achieve simple, convenient, low-cost and rapid preparation of small-width, high-density microchannels. It has the advantages of precise size control, good heat transfer performance, high efficiency, strong scalability, large-scale preparation and industrial application. It is particularly suitable for heat dissipation applications such as enhanced boiling heat transfer.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a small-size, high-density microchannel comprises the following steps:

[0007] Step A: ultrasonically cleaning the target metal substrate using a cleaning agent;

[0008] Step B: coating the target metal substrate with a photosensitive anti-etching ink by spin coating, screen printing, or spray coating, and curing the ink to form a uniform and continuous photosensitive anti-etching protective coating on the target metal substrate, wherein the thickness of the photosensitive anti-etching protective coating is 0.2-10 μm;

[0009] Step C: Using an ultraviolet laser printer to engrave a microchannel mask pattern on the photosensitive etch-resistant protective coating, the minimum line width corresponding to the ultraviolet laser printer is 1-30 μm, the exposed metal surface area in the microchannel mask pattern corresponds to the microchannel area to be formed subsequently, and the area covered by the photosensitive etch-resistant protective coating stripes corresponds to the microchannel wall to be formed subsequently; wherein, the width of the exposed metal surface corresponding to a single microchannel in the microchannel mask pattern is 5-100 μm, and the width of the photosensitive etch-resistant protective coating stripes is 40-500 μm;

[0010] Step D: Immersing the target metal substrate having the microchannel mask pattern in an environmentally friendly etching solution for etching, wherein the environmentally friendly etching solution undergoes an oxidation-reduction reaction with the exposed metal, oxidizing the metal into metal cations that fall off the substrate surface, thereby achieving an etching effect, and obtaining a semi-elliptical microchannel structure with a cross section of a certain depth; for etching small-sized, high-density microchannels on a copper substrate, preferably, the environmentally friendly etching solution is a sodium chloride aqueous solution containing ammonium persulfate, wherein the ammonium persulfate concentration is 20-140 mg / mL, and the mass ratio of sodium chloride to ammonium persulfate is 16:1-1.5:1. During the immersion etching process, the environmentally friendly etching solution is regularly subjected to ultrasonic oscillation or magnetic stirring, and the ultrasonic oscillation or magnetic stirring is performed for 2-60 seconds every 1-5 minutes of etching;

[0011] Step E: Immerse the target metal substrate after etching in a stripping solution that reacts with the photosensitive anti-etching protective coating, so that the photosensitive anti-etching protective coating stripes are peeled off from the surface of the target metal substrate, exposing the microchannel wall, and obtaining a target metal substrate with a small-sized and high-density microchannel structure. The obtained semi-elliptical microchannel has a depth of 10-140 μm, an opening width of 25-300 μm, and a channel density of 18-200 cm -1 .

[0012] In step B of the above preparation method, the curing temperature of the photosensitive anti-etching protective coating is 60-100° C., and the curing time is 1-5 minutes.

[0013] In step C of the above preparation method, when the ultraviolet laser marking machine is used to engrave the microchannel mask pattern, the scanning speed of the laser is 200-1000 mm / s, and the number of scans is 1-10 times.

[0014] In step D of the above preparation method, the immersion etching process mainly controls the etching depth of the microchannel by etching time; in addition, the etching rate can be further regulated by rocking, bubble impact, increasing the temperature of the etching solution, etc., and the temperature of the etching solution is 20-60°C.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. The method for preparing a small-size, high-density microchannel structure proposed by the present invention does not require expensive professional large-scale equipment and a harsh experimental environment. First, the photosensitive blue ink frequently used during the proofing of printed circuit boards (PCB boards) is selected as a protective coating in the etching microchannel process. It has excellent corrosion resistance and is much cheaper than the photoresist used in standard photolithography processes. Simultaneously, a method suitable for preparing ultrathin coatings such as spin coating, screen printing, or spraying is utilized to form a uniform anti-etching coating on the surface of the target metal substrate. The thickness can be controlled to be 0.2-10 μm, which can significantly reduce the time required for subsequent thermal curing, significantly improve production efficiency, and facilitate the preparation of high-precision microchannel mask patterns. Prior art methods such as brushing, roller coating, or scraping are often used to prepare blue oil coatings. The minimum thickness is approximately several hundred microns, and the uniformity is poor, making it only suitable for preparing microstructures with larger sizes and lower densities.

[0017] 2. the present invention is on the basis of preparing ultra-thin blue oil protective coating, directly utilize common industrial ultraviolet laser marking machine to carve out microchannel pattern on its surface, it utilizes laser to remove organic material quickly thereby mark the advantage of pattern, can complete the drafting of microchannel pattern on the blue oil coating of target metal substrate in a few seconds, make part metal surface bare, thereby can be further etched, form the microchannel of different structure size, the minimum line width of preferred industrial ultraviolet laser marking machine is generally 5-20 μm, and line spacing is accurately adjustable, mask pattern can be flexibly designed, can realize the high-precision preparation demand of multiple small-size high-density microchannel pattern. It just utilizes laser to remove the characteristic of ultra-thin blue oil resin quickly, therefore avoids the problems such as the efficiency low, cost high, thermal effect large that laser direct ablation microchannel method exists At the same time, there is also a method in the prior art that uses patterned film to expose and develop the blue oil coating. This method involves a variety of chemicals, the steps are relatively cumbersome, and is affected by exposure accuracy, blue oil coating adhesion strength, film and blue oil coating fit, and development process. It is usually only suitable for processing microstructures with larger size and lower density. When preparing small-size, high-density, high-precision microchannel structures, problems such as large-area development residues or mask pattern damage are prone to occur.

[0018] 3. For the processing of copper-based microchannels, the present invention preferably proposes a formula for an environmentally friendly etching solution, namely, an aqueous sodium chloride solution containing ammonium persulfate. By optimizing the ratio and concentration, it has the advantages of high etching rate and low corrosiveness to other objects. It also proposes a method of regularly ultrasonically oscillating or magnetically stirring the etching solution during the etching process, which can effectively remove objects such as reaction products and air films attached to the metal surface that hinder etching, and can further significantly improve the etching rate and etching uniformity. Compared with commercial etching solutions, the etching rate at room temperature can be increased from 2μm / min to 10μm / min, which helps to achieve high uniformity, high efficiency, high scalability, and large-scale production of small-sized, high-density, high-precision microchannels, suitable for engineering applications.

[0019] 4. The copper etching solution proposed in the invention can spontaneously form a semi-elliptical microchannel structure with a rough channel surface due to anisotropic etching and specific chemical reaction characteristics. Compared with the rectangular and inverted triangular channels often formed by mechanical processing and direct laser ablation, it performs better in terms of pressure drop, heat transfer efficiency and stability. At the same time, the numerous micro-nano structures generated on the channel surface will further increase the heat transfer area and strengthen the bubble dynamics behavior, which is conducive to further improving the boiling heat transfer performance. Experimental tests show that the channel density prepared by the present invention is 61cm -1 The surface of the semi-elliptical microchannel structure with a depth of 30 μm has a CHF and a maximum HTC of 206 W cm -2 and 11.3W cm -2 K -1 , which were increased by 142% and 250% respectively compared with the copper plane, showing a significant boiling heat transfer enhancement effect.

[0020] In summary, the method for preparing small-sized, high-density microchannels proposed in the present invention has the advantages of high dimensional accuracy, fast etching rate, simplicity, high efficiency, low cost, strong scalability, large-scale preparation and engineering application, and has broad prospects in the fields of microfluidics, high heat flow cooling and thermal management of electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Figure 1 This is an optical photograph of the microchannel structure sample prepared in Example 2 of the present invention, with a channel density of 19 cm -1 , the channel depth is 90±2μm, the channel opening width is 280±4μm, and the top width of the channel wall is 220±4μm.

[0023] Figure 2Figure 2 is a comparison diagram of saturated pool boiling heat transfer performance of two different boiling surfaces, i.e., the micro-channel surface 1 in the embodiment 2 of the present application and the smooth copper plane, under normal pressure with deionized water as the working medium, (a) is a boiling curve, and (b) is a heat transfer coefficient curve.

[0024] Figure 3 Figure 3 is an optical photo of the micro-channel structure sample prepared in the embodiment 3 of the present application, which has a channel density of 61 cm -1 , a channel depth of 30±2 μm, a channel opening width of 90±4 μm, and a channel wall top width of 60±4 μm.

[0025] Figure 4 Figure 4 is a comparison diagram of saturated pool boiling heat transfer performance of three different boiling surfaces, i.e., the micro-channel surface 2 in the embodiment 3 of the present application, the micro-channel surface 1 in the embodiment 1 of the present application and the smooth copper plane, under normal pressure with deionized water as the working medium, (a) is a boiling curve, and (b) is a heat transfer coefficient curve. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the present application, the present application will be further described below in conjunction with preferred embodiments and the accompanying drawings. It should be understood by those skilled in the art that the specific description below is illustrative rather than limiting, and should not limit the protection scope of the present application.

[0027] Embodiment 1

[0028] A semi-elliptical micro-channel structure with a channel density of 25 cm -1 on a copper substrate was prepared, including the following steps:

[0029] Step A: ultrasonic cleaning of a round copper sheet with a diameter of 10 mm and a thickness of 1 mm by using a cleaning agent;

[0030] Step B: coating of a photosensitive etching-resistant blue oil on the surface of the target metal substrate by using a spraying method, a blue oil thickness of 800 nm, and heat curing at 90°C for 1 min to form a uniform blue oil protective coating on the surface of the target metal substrate;

[0031] Step C: design of a micro-channel pattern by using a UV laser marking machine, which is composed of 25 parallel lines with a line spacing of 380 μm, laser fast scanning on the blue oil coating layer of the target metal substrate to carve out a micro-channel pattern, a scanning speed of 1000 mm / s, and a scanning number of 1 time. In the formed micro-channel mask pattern, the area with the exposed metal surface has a width of 30 μm, and the micro-channel is formed in the subsequent wet etching process. The area covered by the blue oil coating stripes has a width of 350 μm, corresponding to the subsequent formed micro-channel wall.

[0032] Step D: A total of three target metal substrate samples with microchannel patterns were prepared. Sample 1 was immersed in a commercial copper-friendly etching solution and was slightly shaken periodically during the etching process for comparison as a conventional etching scheme; Sample 2 was immersed in a sodium chloride aqueous solution containing ammonium persulfate, with an ammonium persulfate concentration of 100 mg / mL and a mass ratio of sodium chloride to ammonium persulfate of 7:3. During the etching process, it was slightly shaken periodically; Sample 3 was immersed in a sodium chloride aqueous solution containing ammonium persulfate, with an ammonium persulfate concentration of 100 mg / mL and a mass ratio of sodium chloride to ammonium persulfate of 7:3. During the etching process, the etching solution was ultrasonically oscillated for 10 seconds every 2 minutes; all three samples were etched at room temperature for 5 minutes.

[0033] Step E: Immerse the target metal substrate after the above etching in a stripping solution that can react with the photosensitive anti-etching protective coating, so that the blue oil coating stripes are peeled off from the surface of the target metal substrate, exposing the microchannel wall. 25 semi-elliptical microchannels are prepared on the target metal substrate with a diameter of 10 mm. The channel depths of the three samples are 10 μm, 25 μm and 50 μm, respectively. The etching rates corresponding to the three technical solutions are 2 μm / min, 5 μm / min and 10 μm / min, respectively.

[0034] Example 2

[0035] The channel density on the target metal substrate is 19 cm -1 , a semi-elliptical microchannel structure with a depth of 90 μm, comprising the following steps:

[0036] Step A: ultrasonically clean a round copper sheet with a diameter of 10 mm and a thickness of 1 mm using a cleaning agent;

[0037] Step B: coating the target metal substrate with a photosensitive anti-etching blue oil by screen printing to a thickness of 10 μm, and heat curing at 60° C. for 5 minutes to form a uniform blue oil protective coating on the target metal substrate;

[0038] Step C: Use a UV laser marker to design a microchannel pattern consisting of 19 parallel rectangles with a width of 100 μm and a center-to-center spacing of 500 μm. A laser rapid scan is performed on the blue oil coating of the target metal substrate to engrave the microchannel pattern. The scanning speed is 600 mm / s and the number of scans is 1. In the resulting microchannel mask pattern, the area exposed on the metal surface is 100 μm wide. During the subsequent wet etching process, the microchannel is formed. The area covered by the blue oil coating stripes is 400 μm wide, corresponding to the subsequently formed microchannel wall.

[0039] Step D: Immerse the target metal substrate with the microchannel pattern in a sodium chloride solution containing ammonium persulfate, with an ammonium persulfate concentration of 100 mg / mL and a mass ratio of sodium chloride to ammonium persulfate of 7:3. Wet etching is performed at room temperature for 18 minutes. Periodic shaking is performed during the etching process to accelerate the contact between the reactants and the metal, and also to promote the timely separation of the reaction products from the metal surface, thereby improving the etching uniformity and rate. Due to the isotropic etching characteristics, a semi-elliptical microchannel structure will eventually be etched.

[0040] Step E: Immerse the target metal substrate after the etching described above in a stripping solution that reacts with the photosensitive anti-etching protective coating, so that the blue oil coating stripes are peeled off from the surface of the target metal substrate, exposing the microchannel wall. 19 semi-elliptical microchannels are prepared on the target metal substrate with a diameter of 10 mm. The channel depth is 90±2 μm, the channel opening width is 280±4 μm, and the top width of the channel wall is 220±4 μm.

[0041] The saturated pool boiling heat transfer test was carried out on the microchannel surface. The liquid working medium was deionized water, the test pressure was normal pressure, and a smooth copper plane was used as a reference sample. Figure 2 This is a comparison chart of saturated pool boiling performance. Figure 2 (a) is the boiling curve, Figure 2 (b) is the heat transfer coefficient curve, Figure 2 It can be seen that the boiling performance of the microchannel surface is significantly better than that of the ordinary copper plane. The CHF and maximum HTC are increased by 125% and 197% respectively compared with the copper plane, confirming its beneficial effects and showing important application prospects in the fields of thermal energy conversion, utilization and management.

[0042] Example 3

[0043] The channel density on the target metal substrate is 61cm -1 , a semi-elliptical microchannel structure with a depth of 30 μm, comprising the following steps:

[0044] Step A: ultrasonically clean a round copper sheet with a diameter of 10 mm and a thickness of 1 mm using a cleaning agent;

[0045] Step B: Spin coating the target metal substrate with a photosensitive anti-etching blue oil with a thickness of 5 μm and heat curing for 3 minutes at a curing temperature of 80° C. to form a uniform blue oil protective coating on the target metal substrate;

[0046] Step C: Design the microchannel pattern using a UV laser marker and perform a rapid laser scan on the blue oil coating of the target metal substrate to carve the microchannel pattern. The scan speed is 800 mm / s and the number of scans is 1. The resulting microchannel pattern has a width of 30 μm in the area exposed on the metal surface. During the subsequent wet etching process, the microchannel is formed. The area covered by the anti-etching coating stripes is 120 μm wide, corresponding to the microchannel wall to be formed later.

[0047] Step D: Immerse the target metal substrate with the microchannel pattern in a sodium chloride solution containing ammonium persulfate, where the ammonium persulfate concentration is 100 mg / mL and the mass ratio of sodium chloride to ammonium persulfate is 7:3. Wet etching is performed at room temperature for 3 minutes. During every 1 minute of etching, the etching solution is magnetically stirred for 20 seconds at a speed of 500 rpm. This can effectively remove objects that hinder etching, such as reaction products and air films attached to the metal surface, and can further significantly improve the etching rate and etching uniformity.

[0048] Step E: Immerse the target metal substrate after the etching described above in a stripping solution that can react with the photosensitive anti-etching protective coating, so that the blue oil coating stripes are peeled off from the surface of the target metal substrate, exposing the microchannel wall. 61 semi-elliptical microchannels with a channel depth of 30±2μm, a channel opening width of 90±4μm, and a rib top width of 60±4μm are prepared on the target metal substrate with a diameter of 10mm.

[0049] The saturated pool boiling heat transfer test was performed on the microchannel surface. The liquid working medium was deionized water, the test pressure was normal pressure, and the smooth copper plane and the microchannel surface prepared in Example 1 were used as reference samples. Figure 4 This is a comparison chart of saturated pool boiling performance. Figure 4 (a) is the boiling curve, Figure 4 (b) is the heat transfer coefficient curve, Figure 4 It can be seen that the boiling performance of the microchannel surface is significantly better than that of the ordinary copper plane, with a CHF and maximum HTC of 206 W cm -2 and 11.3W cm -2 K -1 , compared to 85W cm for copper plane -2 and 3.2W cm -2 K -1 , increasing by 142% and 250%, respectively. Furthermore, it can be seen that even with a significantly increased channel density, the boiling heat transfer performance is further enhanced, even with a channel depth of only one-third that of the microchannel in Example 1, confirming the beneficial effects of small-scale, high-density microchannels. Using the method proposed in this invention, small-scale, high-density microchannel structures can be easily fabricated on metal substrates for ultrathin heat transfer devices, resulting in excellent boiling heat transfer performance.

[0050] Obviously, the above-mentioned embodiments of the present application are only examples for clearly explaining the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for preparing a small-size high-density microchannel, characterized in that: The following steps are involved: Step A: ultrasonically cleaning the target metal substrate using a cleaning agent; Step B: coating the target metal substrate with a photosensitive anti-etching ink by spin coating, screen printing, or spray coating, and curing the ink to form a uniform and continuous photosensitive anti-etching protective coating on the target metal substrate, wherein the thickness of the photosensitive anti-etching protective coating is 0.2-10 μm; Step C: Using an ultraviolet laser printer to engrave a microchannel mask pattern on the photosensitive etch-resistant protective coating, the minimum line width corresponding to the ultraviolet laser printer is 1-30 μm, the exposed metal surface area in the microchannel mask pattern corresponds to the microchannel area to be formed subsequently, and the area covered by the photosensitive etch-resistant protective coating stripes corresponds to the microchannel wall to be formed subsequently; wherein, the width of the exposed metal surface corresponding to a single microchannel in the microchannel mask pattern is 5-100 μm, and the width of the photosensitive etch-resistant protective coating stripes is 40-500 μm; Step D: Immersing the target metal substrate having the microchannel mask pattern in an environmentally friendly etching solution for etching, wherein the environmentally friendly etching solution undergoes an oxidation-reduction reaction with the exposed metal, oxidizing the metal into metal cations that fall off the substrate surface, thereby achieving an etching effect, and obtaining a semi-elliptical microchannel structure with a cross section of a certain depth; for etching small-sized, high-density microchannels on a copper substrate, preferably, the environmentally friendly etching solution is a sodium chloride aqueous solution containing ammonium persulfate, wherein the ammonium persulfate concentration is 20-140 mg / mL, and the mass ratio of sodium chloride to ammonium persulfate is 16:1-1.5:

1. During the immersion etching process, the environmentally friendly etching solution is regularly subjected to ultrasonic oscillation or magnetic stirring, and the ultrasonic oscillation or magnetic stirring is performed for 2-60 seconds every 1-5 minutes of etching; Step E: Immerse the target metal substrate after etching in a stripping solution that reacts with the photosensitive anti-etching protective coating, so that the photosensitive anti-etching protective coating stripes are peeled off from the surface of the target metal substrate, exposing the microchannel wall, and obtaining a target metal substrate with a small-sized and high-density microchannel structure. The obtained semi-elliptical microchannel has a depth of 10-140 μm, an opening width of 25-300 μm, and a channel density of 18-200 cm -1 .

2. The method according to claim 1, characterized in that In step B of the above preparation method, the curing temperature of the photosensitive anti-etching protective coating is 60-100° C., and the curing time is 1-5 minutes.

3. The method according to claim 1, characterized in that In step C of the above preparation method, when the ultraviolet laser printer is used to engrave the microchannel mask pattern, the laser scanning speed is 200-1000 mm / s, and the number of scans is 1-10 times.

4. The method according to claim 1, characterized in that In step D of the above preparation method, the immersion etching process mainly controls the etching depth of the microchannel by etching time.

5. The method according to claim 1, characterized in that In addition, the etching rate can be further controlled by using methods such as rocking, bubble impact, and increasing the temperature of the etching solution, wherein the temperature of the etching solution is 20-60°C.

6. A small-size, high-density microchannel prepared according to the method described in any one of claims 1 to 5.

Images