A method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching

Abstract

The present invention discloses a method for preparing a microfluidic heat dissipation chip by modulating a laser beam and combining etching, comprising: controlling a laser light source component to output a laser beam, the laser beam being phase modulated by a spatial light modulator to output multiple laser beams forming a pattern, the multiple laser beams being focused by a galvanometer field mirror scanning system to form a light spot to modify the substrate glass in a corresponding pattern array, wherein the modified pattern array is related to the microfluidic structure; wet etching the modified pattern array on the substrate glass to obtain a microfluidic heat dissipation chip. This method achieves high-efficiency preparation of a microfluidic heat dissipation chip by introducing a spatial light modulator and using a modulated ultrashort pulse laser to induce the glass substrate material with high efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing to prepare micro-channel devices, and in particular relates to a method for preparing a micro-channel heat dissipation chip by modulating a laser beam combined with etching. Background Art

[0002] In the face of the massive demands of the information age, semiconductor devices are being integrated into chips with a trend of high performance, miniaturization and high integration. Correspondingly, high-density device arrangement will bring greater heat dissipation requirements, and the integration of micro devices needs to be matched with efficient cooling components.

[0003] At present, microfluidic devices, as an effective heat dissipation technology, have been widely used in the fields of electronics, energy, chemistry, and biomedicine. In different application scenarios, microfluidic devices can choose a variety of materials. In some application scenarios that require high pressure resistance to reach extremely low temperatures, glass materials are maturely used as substrate materials for microfluidic heat dissipation devices in the preparation process of microfluidics due to their surface stability, hardness, durability, and low heat leakage.

[0004] When preparing glass microfluidic heat dissipation devices, researchers generally use traditional micro-nano processing methods, such as photolithography, deep ion etching, chemical etching and other methods. Its processing flow still faces problems of low efficiency and complex process. For example, when microfluidics of different levels and depths are required in the device, multiple photolithography steps are required, and precise alignment is required between multiple times to complete the overlay. The process is complicated, the processing is difficult, and deviations are prone to occur between multiple alignments. For example, when deep ion etching or chemical etching is used, due to the strong stability of the glass material itself, the etching rate is slow and the processing efficiency is low. In addition, as a transparent hard and brittle material, glass is easy to produce microcracks and other damages during the processing due to its high hardness and brittleness. Its low thermal conductivity will also lead to concentrated high-temperature heat-affected zones during processing. These are problems that need to be solved when preparing microfluidic devices.

[0005] When preparing a glass microfluidic heat sink, a laser is also used to modify the glass material, and then the modified part is etched by chemical etching to obtain a glass microfluidic heat sink. For example, the patent document with publication number CN117727636A discloses a method for preparing a quartz substrate microfluidic channel, in which the quartz glass is laser-drilled, and then wet etching is used to prepare a microfluidic channel in the depth direction. Another example is the patent document with publication number CN114678280A, which discloses a method for preparing a chip microfluidic channel, which uses a laser to carve a preset microfluidic channel structure inside the chip, and uses a hydrogen fluoride solution to etch the damaged structure, forming a microfluidic channel arranged along the preset path in the chip. However, this technical solution can only use one laser beam to modify the glass at a time, and the processing efficiency is low. Summary of the invention

[0006] In view of the above, the purpose of the present invention is to provide a method for preparing a microfluidic heat dissipation chip by modulating a laser beam combined with etching, by introducing a spatial light modulator and using a modulated ultrashort pulse laser to efficiently induce the glass substrate material, so as to achieve efficient preparation of the microfluidic heat dissipation chip.

[0007] To achieve the above-mentioned purpose of the invention, an embodiment provides a method for preparing a microchannel heat dissipation chip by modulating a laser beam combined with etching, comprising the following steps:

[0008] Controlling the laser light source assembly to output a laser beam, the laser beam is modulated by a spatial light modulator to output multiple laser beams forming a pattern, the multiple laser beams are focused by a galvanometer field mirror scanning system to form a light spot to modify the substrate glass in a corresponding pattern array, wherein the modified pattern array is related to the microchannel structure;

[0009] The modified pattern array on the substrate glass is wet-etched to obtain a microfluidic heat dissipation chip.

[0010] The present invention proposes to use a modulated ultrashort pulse laser to induce modification of the substrate glass material for preparing a microfluidic scattering chip. The ultrashort pulse laser concentrates high energy density in a femtosecond or picosecond time scale, bombards the material lattice, and easily induces the material to be modified. Since the time scale of the ultrashort pulse is extremely short and the heat-affected zone is small, defects such as microcracks are avoided to a great extent. In the laser processing stage, a modulated light spot is obtained by using a spatial light modulator, and the light spot array is moved to realize a modified array pattern on the substrate. Unlike traditional photolithography that requires a customized mask, the advantage of modulated laser is that the microfluidic structure can be realized by changing the shape of the light spot, and there is great freedom in designing the microfluidic structure. At the same time, by combining the use of a galvanometer and a field mirror to form a scanning system, the light spot is moved at a high speed on the substrate surface, and the substrate material is quickly modified to improve the processing efficiency. The galvanometer scanning system has a focusing effect on the laser, but due to its long focal depth, the gradient of the laser power density with depth is small, so when the laser is focused on the material surface, the laser has a modifying effect on the material at a certain depth below the substrate surface. By adjusting the depth of the laser focus position, the depth range of material modification can be adjusted accordingly, that is, different levels and depths of microfluidics can be obtained by this method. The laser-processed substrate material is immersed in a solution for wet etching. The laser-modified material is easily etched by the solution, while the unmodified material is difficult to etch. The large contrast in etching rate finally completes the preparation of the microfluidic scattering chip.

[0011] In the present invention, the function of the spatial light modulator is to load a designed phase diagram on the display panel through a computer and corresponding software, change the properties of the liquid crystal material in different areas of the display panel, so that when the incident laser beam is reflected by the display panel of the spatial light modulator, the laser is modulated by the liquid crystal material in different areas, and the properties of the light such as polarization, phase or intensity are purposefully changed. That is, the laser beam is modulated by the spatial light modulator, including changing at least one of the phase, polarization, and intensity of the light.

[0012] Preferably, the laser light source assembly includes a laser, a half-wave plate, and a beam expander. The laser beam output by the laser is polarized by the half-wave plate, and then expanded in diameter by the beam expander before being irradiated to the spatial light modulator.

[0013] After the laser is emitted, it is expanded by a beam expander, and the beam diameter increases. By adjusting the magnification of the beam expander, the diameter of the enlarged beam can be specifically adjusted. The amplification effect of the beam expander is used in conjunction with the subsequent spatial light modulator to select the beam diameter after the expansion according to the expected modulated light spot.

[0014] Preferably, different phase diagrams are displayed on the display panel of the spatial light modulator, and the phase diagrams modulate the light to emit multiple laser beams with different patterns.

[0015] Preferably, the multiple laser beams are adjusted by a lens group and then incident on a galvanometer field lens scanning system to focus the beams, wherein the lens group includes two reflectors and two lenses.

[0016] Preferably, the substrate glass is fixed on a three-dimensional displacement stage, and the modification of the substrate glass at different depths and levels is achieved by adjusting the height position of the three-dimensional displacement stage.

[0017] Preferably, the galvanometer-field lens scanning system is composed of a galvanometer and a field lens, and the light spot is moved on the surface of the substrate glass by the galvanometer-field lens scanning system to achieve modification of the substrate glass.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) Using laser to modify the substrate glass material, the difference in glass material properties between the modified area and the unmodified area is utilized to form a sharp contrast in etching rate, thereby simplifying the process steps of etching the material to form the microchannel.

[0020] (2) During the laser incident process, the spatial light modulator is used to design light spots with different patterns to achieve selective modification of the substrate glass material, replacing the need to customize different masks for different structures in traditional micro-nano processing, thereby reducing processing costs.

[0021] (3) During the laser incident process, the multiple laser beams emitted by the spatial light modulator are adjusted to focus on the depth position of the substrate glass material by using a galvanometer field mirror scanning system, so as to achieve material modification at different levels and depths, replacing the multiple lithography, overlay, alignment and other steps in traditional micro-nano processing, and simplifying the process flow.

[0022] (4) The coordinated use of the spatial light modulator and the galvanometer field mirror scanning system can achieve rapid processing of the entire pattern array, improve processing efficiency, and at the same time have the high-precision advantages of laser processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a flow chart of a method for preparing a microchannel heat dissipation chip by modulating a laser beam combined with etching provided in an embodiment;

[0025] Figure 2 is a light path diagram of laser modification provided in an embodiment;

[0026] Figure 3 is a schematic diagram of a laser focusing surface provided in an embodiment;

[0027] Figure 4 is a schematic diagram of the laser focusing interior provided by the embodiment;

[0028] Figure 5 It is a schematic diagram of the light spot effect provided by the embodiment. DETAILED DESCRIPTION

[0029] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0030] like Figure 1 As shown, the embodiment provides a method for preparing a microchannel heat dissipation chip by modulating a laser beam combined with etching, comprising the following steps:

[0031] S1, controls the laser light source assembly to output a laser beam, which is phase modulated by a spatial light modulator to output multiple laser beams forming a pattern, and the multiple laser beams are focused by a galvanometer field mirror scanning system to form a light spot to modify the substrate glass in a corresponding pattern array, wherein the modified pattern array is related to the microfluidic structure.

[0032] In the embodiment, the optical path for laser modification is first constructed, such as Figure 2 As shown, it includes a laser light source assembly, a spatial light modulator, and a galvanometer field mirror scanning system. Specifically, the laser light source assembly includes a laser, a half-wave plate, and a beam expander. The laser beam is emitted by the laser as a light source. According to the actual optical path requirements, the laser polarization direction is adjusted by the half-wave plate and then passes through the beam expander to expand the beam diameter before irradiating the spatial light modulation to meet the subsequent use requirements of the spatial light modulator and the galvanometer scene scanning system.

[0033] Different phase diagrams are displayed on the display panel on the spatial light modulator, which modulates the incident laser beam and emits multiple laser beams with different patterns. Then, the multiple laser beams with different patterns are adjusted by the lens group and then incident on the galvanometer field mirror scanning system to focus the beam. The lens group includes two reflectors and two lenses. After focusing, the beam is incident on the substrate glass, which is fixed on the three-dimensional displacement stage. By adjusting the height position of the three-dimensional displacement stage, the laser focus can be adjusted to the upper surface of the substrate glass or the inside of the substrate glass. The modification of the substrate glass at different depths and different levels is achieved.

[0034] In the galvanometer field lens scanning system, due to the long focal depth of the galvanometer and field lens system, the power density changes little when the laser is focused. Therefore, when the power density at the laser focus is greater than the laser power threshold for material modification, the laser power near the focus height position is still greater than the material modification threshold. Within the height range where the laser power density is greater than the modification threshold, the material is modified by the laser. The corresponding depth and area materials that are not irradiated by the laser maintain their original state, and the two have different material properties. The height position of the three-dimensional translation stage can be adjusted to achieve focusing the laser at different heights, such as Figure 3 The substrate glass surface shown or Figure 4 The inside of the substrate glass shown in the figure can modify the material near the depth of the laser focus, so that laser modification of materials at different depths can be achieved, corresponding to the final preparation of microchannel structures of different levels and depths.

[0035] S2, wet etching the modified pattern array on the substrate glass to obtain a microfluidic heat dissipation chip.

[0036] The substrate glass that has been partially modified by laser is immersed in a solution for wet etching. The glass that has been modified by laser and the glass that has not been modified by laser are etched at different rates by the solution. The substrate glass that has been modified by laser is etched quickly, while the substrate glass that has not been modified by laser is etched very slowly, thus forming structures with different heights.

[0037] Specifically, the modulation function of the spatial light modulator is to change the intensity distribution of the laser beam. The following examples are given to illustrate the correlation between the achievable light spot and the processing of the microfluidic structure:

[0038] 1. For example 1 of the microfluidic structure, the horizontal rows are regularly arranged cylinders, and there is a dislocation arrangement between the horizontal rows. The cylinder structure contained in the microfluidic structure is large, that is, >50um diameter, then a single modulated light spot can be designed, such as Figure 5 As shown, a spot pattern with a square outside and a circular inside is formed, with strong laser in the gray area and weak laser in the white area. This spot pattern is scanned in the form of an array on the substrate glass to selectively modify the substrate glass. After solution etching, a structure with a cylindrical array arranged on a flat substrate is obtained.

[0039] During the modulation process of the spatial light modulator, the light intensity distribution of the incident laser is changed so that the laser is evenly distributed in the gray area of ​​the outer square frame, while the laser intensity is extremely weak in the central circle. Since its light intensity is far below the modification threshold of the substrate material, it can be considered that the weak light in the circular area does not modify the substrate material at all.

[0040] Through the combination of the galvanometer and field mirror at the rear end of the optical path, according to the size of the modulated light spot (i.e., the lengthening of the outer square frame), the moving step of the light spot is set to the side length. Combined with the repetition frequency of the laser and the moving speed of the light spot in the galvanometer, the light spot is moved when the laser is turned off, and the material is modified at the target position when the laser is turned on. By completing the moving path of the laser spot, the modified result with regular distribution in each row and dislocations between different rows is finally obtained. The result of the laser modification of the substrate material is etched to obtain the lower microchannel structure shown in the figure below.

[0041] In the above method, the light spot is designed by using a spatial light modulator to achieve selective modification of the substrate glass in the form of a multi-spot array. At the same time, the light spot array is related to the microfluidic structure. The light spot is directly used to replace the need to customize different masks for different structures when traditional micro-nano processing is performed, thereby reducing processing costs. At the same time, a light spot array of multiple light beams is used for material modification. Compared with the existing material modification with one light beam in multiple cycles, rapid processing of the entire array pattern is achieved, improving processing efficiency, while also having the high-precision advantage of laser processing.

[0042] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a microchannel heat dissipation chip by modulating a laser beam combined with etching, characterized in that: The following steps are involved: Controlling the laser light source assembly to output an ultrashort pulse laser beam, the ultrashort pulse laser beam is modulated by a spatial light modulator to output multiple ultrashort pulse laser beams forming a pattern, the multiple ultrashort pulse laser beams are focused by a galvanometer field mirror scanning system to form a light spot to modify the substrate glass in a corresponding pattern array, wherein the modified pattern array is related to the microchannel structure; The galvanometer field mirror scanning system is composed of a galvanometer and a field mirror. The galvanometer field mirror scanning system moves the light spot on the surface of the substrate glass to achieve the modification of the substrate glass. When the laser is focused on the surface of the material, the laser has a modification effect on the material at a certain depth below the substrate surface. By adjusting the depth of the laser focus position, the depth range of the material modification is correspondingly adjusted, that is, different levels and depths of the microchannel are obtained; Specifically, a spot pattern with an outer square and an inner circle is formed. By changing the light intensity distribution of the incident laser, the laser is evenly distributed in the intersection area formed inside the outer square and outside the inner circle, that is, the laser is strong in the intersection area, while the laser intensity is weak in the center circle. When the power density at the laser focus is greater than the laser power threshold of material modification, the laser power near the focus height position is still greater than the material modification threshold. Within the height range where the laser power density is greater than the modification threshold, the material is modified by the laser, and the corresponding depth and area material that has not been irradiated by the laser maintains its original state, and the two have different material properties. The modified pattern array on the substrate glass is wet-etched to obtain a microfluidic heat dissipation chip.

2. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 1, characterized in that: Modulation includes changing at least one of the phase, polarization, and intensity of the light.

3. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 1, characterized in that: The laser light source assembly includes a laser, a half-wave plate, and a beam expander. The laser beam output by the laser is polarized by the half-wave plate, and then expanded by the beam expander to irradiate the spatial light modulator.

4. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 1, characterized in that: Different phase diagrams are displayed on the display panel of the spatial light modulator, and multiple laser beams with different patterns are emitted after the phase diagram modulates the light.

5. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 1, characterized in that: Multiple laser beams are adjusted by a lens group and then incident on a galvanometer field mirror scanning system to focus the beams.

6. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 5, characterized in that: The lens group includes a reflector and a lens.

7. The method for preparing a microchannel heat dissipation chip by modulating laser beam combined with etching according to claim 1, characterized in that: The substrate glass is fixed on a three-dimensional displacement stage, and modifications of different depths and levels of the substrate glass are achieved by adjusting the height position of the three-dimensional displacement stage.

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