Device and method for preparing crystalline silicon surface metal microstructure through laser drive control localized electro-deposition

Abstract

The invention discloses a device and method for preparing a crystalline silicon surface metal microstructure through laser-driven localized electro-deposition. In the device, an electrochemical loop is formed among electrolyte, an anode and a semiconductor wafer; a laser beam emitted by the second laser irradiates the semiconductor wafer for maskless localized electro-deposition processing, and a laser beam emitted by the first laser is split by the optical splitter and then irradiates the anode and the processed surface of the semiconductor wafer respectively; the device is used for heating the anode so as to adjust the distance between the anode and the semiconductor wafer, thereby regulating and controlling the deposition rate and the size and morphology of a deposition layer, and carrying out synchronous heat treatment on a metal microstructure deposited on the processed surface of the semiconductor wafer. By means of the method, it can be guaranteed that a localized conductive channel is induced to be generated at the laser irradiation position of the monocrystalline silicon surface, then laser-induced mask-free localized electro-deposition on the silicon surface is achieved, and the problems that at present, the deposition process on a semiconductor material is tedious, and the step-by-step operation efficiency is low are solved.

Description

Technical Field

[0001] The present invention relates to the field of special processing, and in particular to a device and a method for preparing a metal microstructure on a crystalline silicon surface by laser-driven localized electrodeposition. Background Art

[0002] Semiconductor materials such as silicon and germanium play a central role in many high-tech fields due to their outstanding physical and chemical properties. These materials are not only the cornerstones of modern electronic devices, but also have a wide range of applications in photovoltaic technology, advanced medical devices and precision micro-electromechanical systems (MEMS). Using sophisticated surface micromachining techniques, complex micro-nano structures can be created on these semiconductor materials to give them specific functions and improve their performance. For example, submicron-scale periodic microgrooves not only enhance the anti-reflection ability of the material, but also improve the efficiency of optoelectronic devices through precise regulation of optical properties; honeycomb micropit arrays can be used as microlens arrays in optical applications, greatly enriching the application range of imaging technology; at the same time, by precisely controlling the microstructure design of the surface, the adjustability of the material surface from superhydrophilic to superhydrophobic can be achieved, which is of great significance in the fields of materials science and surface engineering.

[0003] Despite the many advantages of semiconductor materials, their high brittleness and low fracture toughness limit their operability in micromachining processes, especially when it comes to micron or even nanoscale processing. This challenge is even more significant. In order to overcome these limitations, research institutions around the world have continuously explored and optimized the processing technology of semiconductor materials in the past few decades. At present, the main methods of micromachining technology include micro-turning / milling, electrolytic machining, photolithography, chemical etching and laser machining. Each technology has its unique application scenarios and advantages, but it is also accompanied by certain limitations. For example, although micro-turning / milling technology can achieve extremely high precision, its single-step feed amount needs to be controlled below 250 nanometers to prevent material damage, which greatly limits the processing efficiency; the application of electrolytic machining in semiconductor materials is limited by lower current density, and the processing efficiency is not as good as that of metal materials; and traditional laser processing is prone to thermal damage on semiconductor materials. Although femtosecond laser technology alleviates this problem, its equipment cost is high and the removal efficiency is low.

[0004] In practical applications, in order to solve the limitations of a single technology and improve processing efficiency and quality, a variety of composite processing technologies have been developed. These technologies combine mechanical force, laser, electrochemical anodic dissolution, electrochemical discharge, chemical corrosion, water jet impact and other means to make complex microstructure processing possible. For example, by combining laser and electrochemical processing, it is possible to reduce physical and chemical damage during processing while maintaining high precision, and achieve more efficient material removal and surface treatment. In addition, by integrating chemical corrosion and micromachining technology, materials in specific areas can be accurately removed without damaging the substrate. This multi-technology fusion method not only improves the processing quality and efficiency of semiconductor materials, but also promotes the advancement of micro-nano manufacturing technology, opening up new possibilities for the future application of semiconductor materials. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a device and a method for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition. By laser irradiating the high-melting-point anode A side, the temperature of the anode A side is caused to rise, and the memory alloy on the anode B side is stretched through temperature conduction, so as to achieve precise and controllable fine-tuning of the distance between the front end of the anode and the cathode crystalline silicon surface, thereby achieving precise control of the inter-electrode electric field, and further controlling the deposition rate and the size and morphology of the deposited layer.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition comprises a second laser, an anode, a spectrometer and a first laser; the anode is connected to the positive electrode of a direct current pulse power supply, the negative electrode of the direct current pulse power supply is connected to a semiconductor wafer, and an electrochemical circuit is formed between the electrolyte, the anode and the semiconductor wafer; the laser beam emitted by the second laser is irradiated on the semiconductor wafer for maskless localized electrodeposition processing, and the laser beam emitted by the first laser is split by the spectrometer and irradiated on the anode and the processed surface of the semiconductor wafer respectively, so as to heat the anode so as to adjust the distance of the anode relative to the semiconductor wafer so as to control the deposition rate and the size and morphology of the deposition layer, and to perform synchronous heat treatment on the metal microstructure deposited on the processed surface of the semiconductor wafer.

[0008] In the above solution, the angle between the anode and the semiconductor wafer is less than 90°.

[0009] In the above scheme, the anode includes an anode A side and an anode B side, and the anode A side and the anode B side are memory materials. The telescopic length of the anode is controlled by heating to achieve an adjustable distance between the front end of the anode and the surface of the semiconductor wafer, thereby achieving an enhancement or weakening of the electric field between the anode and the semiconductor wafer, and further regulating the deposition rate and the size and morphology of the deposition layer.

[0010] In the above scheme, the anode is fixed by a clamp support, and the anode A side and the anode B side are slidably connected; the thermal expansion coefficients of the anode A side and the anode B side are different, and the thermal expansion coefficient of the anode B side is higher than that of the anode A side.

[0011] In the above solution, the electrical conductivity of the semiconductor wafer increases with the increase of temperature and external light / laser irradiation, including but not limited to single crystal silicon, single crystal germanium or silicon carbide.

[0012] In the above scheme, the laser parameters of the processed metal microstructure are: pulse width 1 to 500 ns, power 1.5 W, spot diameter 30 μm, scanning speed 3000 mm / s, frequency 3 MHz, and processing time 5 min.

[0013] The invention discloses a method for preparing a device for preparing a metal microstructure on a crystalline silicon surface by laser-driven localized electrodeposition, which utilizes the photothermal effect and photoconductive effect of laser irradiation to induce a high conductivity region at a designated position of a semiconductor wafer, realizes local enhancement of current density, and then induces maskless localized electrodeposition to obtain a micro-line or micro-pattern designated metal microstructure, and regulates the deposition rate and the size and morphology of the deposited layer by adjusting the distance between the anode and the semiconductor wafer, and utilizes laser to heat-treat the metal microstructure while processing the metal microstructure; the method comprises the following steps:

[0014] Step 1: Turn on the switches of the first laser and the second laser to start preheating, and move the electrodeposition tank to a suitable processing position in the horizontal plane by adjusting the XY linear motion platform;

[0015] Step 2: Turn on the computer and confirm that the software is running normally. After the waterproof pretreatment is completed, the semiconductor wafer is placed in the electrodeposition tank and the electrolyte is poured until the semiconductor wafer is covered by 1 to 2 mm.

[0016] Step 3: Adjust the parameters of the first laser through a computer to make the anode begin to stretch, adjust the parameters until the distance between the anode and the surface of the semiconductor wafer is 2 to 3 mm, draw the required deposited gate image on the computer, and start the second laser after confirming that the preparation work is correct. The laser beam emitted by the second laser is adjusted by a beam expander and a 45° reflector, and then accurately focused on the surface of the semiconductor wafer through a galvanometer and a lens for deposition;

[0017] Step 4: The composite processing head is moved toward the unprocessed side through computer adjustment, so that the unprocessed surface is irradiated by the second laser for deposition, and the processed surface is irradiated by the light beam emitted by the first laser for secondary processing, and the primary processing and the secondary processing are performed simultaneously;

[0018] Step 5. After the processing is completed, adjust the laser parameters through the computer, close the processing process, and end the processing after the anode retracts to the initial length. Adjust the XY linear motion platform to remove the semiconductor wafer with the metal microstructure after processing, and adjust the composite processing head to the initial position, then turn off the system power to complete the processing.

[0019] Beneficial effects:

[0020] (1) The present invention aims at the problem of poor processing technology of semiconductor materials such as semiconductor wafers. Based on the sensitivity of semiconductor wafer conductivity to temperature, the photothermal effect and photoconductivity effect of laser irradiation can be used to achieve localized improvement of semiconductor wafer conductivity; at the same time, when the energy of laser single photons is greater than the bandgap width of the semiconductor wafer, the conductivity of the semiconductor wafer can be improved by the photoconductivity effect of the laser. The above two effects can ensure that a localized conductive channel is induced at the laser irradiation point on the surface of the semiconductor wafer, thereby achieving laser-induced maskless localized electrodeposition on the surface of the semiconductor wafer, solving the problem of cumbersome deposition process on semiconductor materials and low efficiency of step-by-step operation.

[0021] (2) The present invention utilizes two memory alloys with different thermal expansion coefficients as anodes. When irradiated by laser, the anode expands and contracts as the temperature rises. By precisely and controllably adjusting the distance between the front end of the anode and the surface of the cathode semiconductor wafer, the inter-electrode electric field is precisely regulated, thereby realizing the preparation of deposition layers of different thicknesses. At the same time, by adjusting the laser parameters of the processing system and adjusting the intensity of laser irradiation, the internal electric field of the semiconductor wafer material can be enhanced to induce maskless localized deposition, and the electric field between the anode and cathode can be strengthened to enhance localized electrodeposition and optimize the surface quality of the coating.

[0022] (3) The present invention uses a beam splitter to split the light beam emitted by the first laser into two beams, one of which is irradiated on the anode side to control the expansion and contraction of the anode, and the other is irradiated on the surface of the processed material. Through the laser thermal effect, the metal microstructure surface of the processed material instantly reaches the heat treatment temperature, eliminating the Schottky barrier between the metal and the semiconductor surface, enhancing the bonding performance of the metal layer and the crystalline silicon, forming a good ohmic contact, and at the same time improving the morphology of the deposited layer by heating and melting. In addition, since the material is isolated from the air in the electrodeposition solution, oxidation can be avoided after reaching the heat treatment temperature.

[0023] (4) The processing system of the present invention has perfect functions and is easy to assemble and implement. The laser-driven localized electrodeposition system for preparing metal microstructures on the surface of crystalline silicon is simple and easy to understand, and is convenient for installation and maintenance.

[0024] (5) This method has wide applicability and can be extended to other semiconductor wafer surface electrodeposition scenarios.

[0025] (6) This method can realize the efficient, flexible and localized preparation of metal microstructures on the surface of crystalline silicon without the assistance of masks. It can be applied to the preparation of photovoltaic cell grid electrode, integrated circuit surface microstructure deposition and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to the present invention;

[0027] Figure 2 This is a curve of the distance between the anode and cathode and the coating thickness.

[0028] Reference numerals:

[0029] 1-ammeter; 2-DC pulse power supply; 3-computer; 4-second laser; 5-beam expander; 6-reflector; 7-galvanometer; 8-temperature sensor; 9-lens; 10-anode; 11-beam splitter; 12-first laser; 13-electrodeposition tank; 14-semiconductor wafer; 15-XY linear motion platform. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] A method for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition, which utilizes the photothermal effect and photoconductive effect of laser irradiation to generate a high conductivity area at a specified position of the silicon material, thereby inducing maskless localized electrodeposition. At the same time, a laser-driven retractable anode is designed. By changing the laser irradiation parameters, the memory metal anode is expanded and contracted due to temperature changes, thereby achieving precise and controllable fine-tuning of the distance between the front end of the anode and the surface of the cathode semiconductor wafer, thereby achieving precise control of the inter-electrode electric field and the preparation of deposited layers of different thicknesses. At the same time, the split light beam and the reflected light beam at the anode can perform subsequent heat treatment on the deposited metal microstructure, and the morphology of the deposited layer can be improved and the composition can be dissolved by heating, thereby further enhancing the bonding performance and electrical contact performance of the metal layer with the crystalline silicon. The laser beam emitted by the first laser 12 is divided into two sub-beams by the beam splitter 11. The first sub-beam is irradiated to the processed surface to perform subsequent heat treatment on the deposited metal microstructure on the surface of the semiconductor wafer; at the same time, the second sub-beam is irradiated to the anode A side. The temperature of the anode A side rises due to the irradiation and is transmitted to the anode B side, so that the memory alloy on the anode B side is stretched, thereby adjusting its distance from the cathode semiconductor wafer surface. The reflected light of the second sub-beam on the anode A side can also act on the deposited microstructure to achieve synchronous heating; the second laser 4 emits a laser beam that directly irradiates the surface of the crystalline silicon material to form a high conductivity area at a specified position, thereby achieving maskless localized electrodeposition; the semiconductor wafer 14 is connected to the negative electrode of the DC pulse power supply 2 as a cathode, and the positive electrode of the DC pulse power supply 2 is connected to the anode 10. The electrodeposition liquid forms a thin liquid layer on the surface of the material, forming a passage with the anode and the cathode to ensure the normal processing process.

[0034] The laser parameters for inducing micro copper wires and metal microstructures on the surface of the semiconductor wafer 14 are as follows: nanosecond laser, pulse width 1 to 500 ns, power 1.5 W, spot diameter 30 microns, scanning speed 300 mm / s, frequency 1 MHz, and processing time 5 min.

[0035] The cathode material is a semiconductor wafer whose electrical conductivity significantly increases when the temperature rises or when exposed to external light, including but not limited to single crystal silicon, single crystal germanium, silicon carbide, etc.

[0036] The laser beam emitted by the first laser 12 is divided into two sub-beams by the beam splitter 11 to realize the corresponding functions. The first sub-beam is irradiated to the surface of the processed material to perform subsequent heat treatment on the deposited metal microstructure; the second sub-beam is irradiated to the anode A side. The anode 10 is composed of two alloys with different thermal expansion coefficients, wherein the alloy on the anode A side has a low thermal expansion coefficient and a high melting point, and basically does not deform after laser irradiation, and the memory alloy on the anode B side has a high thermal expansion coefficient. When the temperature of the anode A side rises due to laser irradiation and is transmitted to the anode B side, the memory alloy on the anode B side is elongated due to the temperature rise; in addition, the temperature of the anode B side can be monitored on the computer 3 through the temperature sensor 8 connected to the anode B side, and the parameters of the beam splitter 11 are changed in real time according to the temperature curve of the anode B side material, and the output energy of the first sub-beam and the second sub-beam are fine-tuned to achieve accurate and controllable fine-tuning of the distance between the anode front end and the cathode crystalline silicon surface, thereby realizing accurate regulation of the inter-electrode electric field to realize the preparation of deposited layers of different thicknesses. The size of the telescopic anode front end can be adjusted according to the specific deposition microstructure size requirements (nanometer-micrometer level), and the deposition requirements of microstructures of different scales can be met through electric field concentration.

[0037] Before the electrodeposition preparation, the second laser 4 can be used to perform micro-etching such as grooving and opening holes on the surface of the semiconductor wafer according to the processing requirements to remove substances such as silicon dioxide film on the surface of the crystalline silicon material, and then localized electrodeposition is performed inside the micro-etched structure.

[0038] The first laser 12 is divided into a beam 1 by a beam splitter 11 and directly irradiates the surface of the processed material. The second beam is irradiated on the side surface of the anode A and is also irradiated on the processed surface after being reflected by the side surface (mirror) of the anode A. The first beam and the reflected beam at the anode can simultaneously perform subsequent heat treatment on the deposited metal microstructure. Since the output power of the first laser 12 has not changed during the above-mentioned process of adjusting the parameters of the beam splitter 11, when the reflected beam of the second beam and the first beam arrive at the post-processing area, their total power will change slightly due to the adjustment of the beam splitter parameters, but will still be maintained at an overall stable level, so that the processed surface can instantly reach the annealing temperature of the deposited material. Under high temperature and air-isolated conditions, rapid annealing of the metal is performed to enhance the bonding performance between the metal layer and the crystalline silicon. At the same time, the morphology of the deposited layer is improved by heating and melting to optimize the microstructure and performance of the deposited metal surface.

[0039] The electrodeposition solution used in the electrodeposition tank 13 is a precisely formulated acidic metal salt solution, the concentration and pH value of which are adjusted according to specific deposition requirements to ensure the optimization of deposition efficiency and material surface quality.

[0040] The second laser 4 controlled by the computer 3 can perform maskless localized electrodeposition on the surface of the semiconductor wafer 14 to accurately generate the required coating pattern. This process uses a specially designed computer program to control the laser scanning path according to preset parameters to accurately prepare a uniform material deposition layer in a specified area; in addition, by adjusting the irradiation intensity of the second laser 4, the electric field between the anode and cathode and the conductivity of crystalline silicon can be controlled in real time, and with the control of the laser scanning path, scanning speed, etc., the thickness and width of the microstructure deposition can be dynamically controlled.

[0041] A device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition, comprising an anode adjustment system and a laser electrochemical micromachining system; the anode adjustment system comprises a first laser 12, a beam splitter 11, a temperature sensor 8, an anode A side and an anode B side, and is used to adjust the distance between the front end of the anode and the cathode crystalline silicon surface; the laser electrochemical micromachining system comprises a second laser 4, an optical adjustment component including a beam expander 5, a reflector 6, a galvanometer 7 and a lens 9, a DC pulse power supply 2, an electrodeposition tank 13, an ammeter 1 and an XY linear motion platform 15, and is used to perform machining operations.

[0042] The anode adjustment system includes a first laser 12, a beam splitter 11, a temperature sensor 8, an anode A side and an anode B side. The anode 10 is composed of two alloys with different thermal expansion coefficients, wherein the thermal expansion coefficient of the alloy on the anode A side is low and basically does not deform after laser irradiation, and the thermal expansion coefficient of the memory alloy on the anode B side is high. The laser beam emitted by the first laser 12 is divided into two sub-beams by the beam splitter 11, and the second sub-beam is irradiated to the anode A side. The temperature of the anode A side rises due to the irradiation and is transmitted to the anode B side, so that the memory alloy on the anode B side is stretched. The anode temperature is monitored on a computer through the temperature sensor 8, and the parameters of the first laser 12 are dynamically adjusted to maintain the processing system in a steady state, so as to achieve precise and controllable fine-tuning of the distance between the front end of the anode and the cathode crystalline silicon surface, and achieve precise regulation of the inter-electrode electric field to prepare deposition layers of different thicknesses.

[0043] The laser electrochemical micromachining system includes a second laser 4, an optical adjustment component including a beam expander 5, a reflector 6, a galvanometer 7 and a lens 9, a DC pulse power supply 2, an electrodeposition tank 13, an ammeter 1 and an XY linear motion platform 15. The laser beam emitted by the second laser 4 is adjusted by the beam expander 5 and the 45° reflector 6, and then accurately focused on the surface of the crystalline silicon to be processed through the galvanometer 7 and the lens 8. The system configuration ensures that a liquid layer thickness of 2 to 3 mm is formed between the semiconductor wafer 14 and the anode 10, so that the circuit between the cathode and the anode is conductive. The first laser 12 and the second laser 4 are both configured as nanosecond pulse lasers or picosecond / femtosecond ultra-pulse lasers to provide precise energy control of different time scales according to processing requirements, thereby achieving fine adjustment and optimization of the surface treatment of semiconductor materials.

[0044] Embodiment 1: This embodiment is a method for preparing metal microstructures on the surface of crystalline silicon based on laser-driven localized electrodeposition. The second laser 4 emits a laser beam that is focused on the surface of the crystalline silicon material after being adjusted by an external optical path, and uses the thermal effect and photoconductivity effect of laser irradiation to perform maskless surface localized electrodeposition. On this basis, the first laser 12 emits a laser beam that is divided by a beam splitter, and the first sub-beam is irradiated to the processed surface, and controllable secondary processing can be performed on the processed surface to optimize the coating quality. The second sub-beam is irradiated to the anode A side, and the telescopic length of the anode B side is controlled by irradiation heating, so as to achieve precise and controllable fine-tuning of the distance between the front end of the anode and the cathode crystalline silicon surface, thereby achieving precise regulation of the inter-electrode electric field and the preparation of deposition layers of different thicknesses.

[0045] The electrodeposition solution used in the electrodeposition tank is a precisely formulated acidic metal salt solution, the concentration and pH value of which are adjusted according to the specific deposition requirements to ensure the optimization of deposition efficiency and material surface quality.

[0046] Embodiment 2: Combination with Figure 1 The present embodiment is a system for preparing a metal microstructure on a crystalline silicon surface based on laser-driven localized electrodeposition, including an anode adjustment system and a laser electrochemical micromachining system; the anode adjustment system includes a first laser, a beam splitter, an anode A side and an anode B side, and is used to adjust the distance between the front end of the anode and the cathode crystalline silicon surface; the system includes a first laser, a beam splitter, an anode A side and an anode B side, the anode is composed of two alloys with different thermal expansion coefficients, wherein the thermal expansion coefficient of the alloy on the anode A side is low and basically does not deform after laser irradiation, and the thermal expansion coefficient of the memory alloy on the anode B side is high, the laser beam emitted by the first laser is divided into two sub-beams by the beam splitter, and the sub-beam 2 is irradiated to the anode A side, and the temperature of the anode A side rises due to the irradiation and is transmitted to the anode B side, so that the memory alloy on the anode B side is stretched, and by adjusting the parameters of the first laser 12, the distance between the front end of the anode and the cathode crystalline silicon surface can be accurately and controllably fine-tuned, and the inter-electrode electric field can be accurately regulated to prepare deposition layers of different thicknesses.

[0047] Embodiment 3: Combination Figure 1 , this embodiment is a laser electrochemical micromachining system, including a laser 2, an optical adjustment component (including a beam expander, a reflector, a galvanometer and a lens), a DC pulse power supply, an electrodeposition tank, an ammeter and an XY linear motion platform. The laser beam emitted by the second laser 4 is adjusted by a beam expander and a 45° reflector, and then accurately focused on the surface of the crystalline silicon to be processed through a galvanometer and a lens. The system configuration ensures that a liquid layer thickness of 2 to 3 mm is formed between the semiconductor material and the anode, so that the circuit between the cathode and the anode is conductive. The first laser 12 and the second laser 4 are both configured as nanosecond pulse lasers or picosecond / femtosecond ultra-pulsed lasers to provide precise energy control of different time scales according to processing requirements, thereby achieving fine adjustment and optimization of the surface treatment of semiconductor materials.

[0048] Working process:

[0049] Step 1: Turn on the switches of the first laser 12 and the second laser 4 to start preheating, and move the electrodeposition tank to a suitable processing position in the horizontal plane by adjusting the XY linear motion platform;

[0050] Step 2: Turn on the computer and confirm that the software is running normally. After the waterproof pretreatment is completed, the crystalline silicon material is placed in the electrodeposition tank, and the electrodeposition liquid prepared in advance is poured in until the workpiece is covered by 4 to 5 mm;

[0051] Step 3: Adjust the parameters of the first laser 12 through the computer to make the anode start to stretch, adjust the parameters until the distance between the anode and the workpiece surface is 2 to 3 mm, draw the required deposition grid image on the computer, and start the second laser 4 after confirming that the preparation work is correct. The laser beam emitted by the second laser 4 is adjusted by the beam expander and the 45° reflector, and then accurately focused on the surface of the material to be processed through the galvanometer and the lens for deposition;

[0052] Step 4: The composite processing head (in the dotted box) is moved toward the unprocessed side by computer adjustment, so that the unprocessed surface is irradiated by the second laser 4 for deposition, and the processed surface is irradiated by the light beam emitted by the first laser 12 for secondary processing. The primary processing and the secondary processing are performed simultaneously. In addition, the laser electrochemical micro-processing system and the workpiece material are ensured to move smoothly and at a uniform speed to ensure that the surface quality of the processed microstructure is good and the width is uniform.

[0053] Step 5. After the processing is completed, adjust the laser parameters through the computer, close the processing process, and end the processing after the anode retracts to the initial length. Adjust the XY linear motion platform to remove the semiconductor wafer 14 with the metal microstructure after processing, and adjust the composite processing head to the initial position, then turn off the system power and complete the processing.

[0054] Combined with Figure 2 As shown, the reduction of the inter-electrode distance can effectively increase the inter-electrode electric field, thereby increasing the coating thickness. For the same deposition time, the smaller the inter-electrode distance, the thicker the coating deposition.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0056] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition, characterized in that: The invention comprises a second laser (4), an anode (10), a beam splitter (11) and a first laser (12); the anode (10) is connected to the positive electrode of a direct current pulse power supply (2), the negative electrode of the direct current pulse power supply (2) is connected to a semiconductor wafer (14), and an electrochemical circuit is formed between the electrolyte, the anode (10) and the semiconductor wafer (14); the laser beam emitted by the second laser (4) is irradiated on the semiconductor wafer (14) to perform maskless localized electrodeposition processing, and the laser beam emitted by the first laser (12) is split by the beam splitter (11) and irradiated on the anode (10) and the processed surface of the semiconductor wafer (14) respectively, so as to heat the anode (10) so as to adjust the distance between the anode (10) and the semiconductor wafer (14), thereby regulating the deposition rate and the size and morphology of the deposition layer, and to perform synchronous heat treatment on the metal microstructure deposited on the processed surface of the semiconductor wafer (14).

2. The device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to claim 1, characterized in that: The angle between the anode (10) and the semiconductor wafer (14) is less than 90°.

3. The device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to claim 1, characterized in that: The anode (10) comprises an anode A side and an anode B side, wherein the anode A side and the anode B side are memory materials, and the telescopic length of the anode (10) is controlled by heating to achieve an adjustable distance between the front end of the anode and the surface of the semiconductor wafer (14), thereby achieving an enhancement or weakening of the electric field between the anode (10) and the semiconductor wafer (14), and further regulating the deposition rate and the size and morphology of the deposition layer.

4. The device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to claim 3, characterized in that: The anode (10) is supported and fixed by a clamp, and the anode A side and the anode B side are slidably connected; the anode A side and the anode B side have different thermal expansion coefficients, and the thermal expansion coefficient of the anode B side is higher than that of the anode A side.

5. The device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to claim 1, characterized in that: The electrical conductivity of the semiconductor wafer (14) is enhanced with increasing temperature and external light / laser irradiation, and includes but is not limited to single crystal silicon, single crystal germanium or silicon carbide.

6. The device for preparing metal microstructures on the surface of crystalline silicon by laser-driven localized electrodeposition according to claim 1, characterized in that: The laser parameters of the processed metal microstructure are: pulse width 1-500ns, power 1.5W, spot diameter 30μm, scanning speed 3000mm / s, frequency 3MHz, and processing time 5min.

7. The method for preparing the device for preparing metal microstructure on the surface of crystalline silicon by laser-driven localized electrodeposition according to any one of claims 1 to 6, characterized in that: The photothermal effect and photoconductive effect of laser irradiation are used to induce a high conductivity area at a designated position of a semiconductor wafer (14), thereby achieving localized enhancement of current density, thereby inducing maskless localized electrodeposition, and obtaining a micro-line or micro-pattern designated metal microstructure. The deposition rate and the size and morphology of the deposited layer are regulated by adjusting the distance between the anode (10) and the semiconductor wafer (14). The metal microstructure is heat treated by laser while the metal microstructure is processed. The method comprises the following steps: Step 1: Turn on the switches of the first laser (12) and the second laser (4) to start preheating, and move the electrodeposition tank (13) to a suitable processing position in the horizontal plane by adjusting the XY linear motion platform (15); Step 2, turn on the computer (3), confirm that the software runs normally, place the semiconductor wafer (14) in the electrodeposition tank (13) after the waterproof pretreatment is completed, and pour the electrolyte until the semiconductor wafer (14) is covered by 1 to 2 mm; Step 3, adjusting the parameters of the first laser (12) through the computer (3) so that the anode (10) begins to stretch, adjusting the parameters until the distance between the anode (10) and the surface of the semiconductor wafer (14) is 2 to 3 mm, drawing the desired deposition gate image on the computer (3), and starting the second laser (4) after confirming that the preparation work is correct. The laser beam emitted by the second laser (4) is adjusted by a beam expander and a 45° reflector, and then accurately focused on the surface of the semiconductor wafer (14) through a galvanometer and a lens for deposition; Step 4, the composite processing head is moved toward the unprocessed side by adjusting through the computer (3), so that the unprocessed surface is irradiated by the second laser (4) for deposition, and the processed surface is irradiated by the light beam emitted by the first laser (12) for secondary processing, and the primary processing and the secondary processing are performed simultaneously; Step 5, after the processing is completed, the laser parameters are adjusted through the computer (3), the processing process is closed, and the processing is terminated after the anode (10) retracts to the initial length. The XY linear motion platform (15) is adjusted to take out the semiconductor wafer (14) with the metal microstructure after processing, and the composite processing head is adjusted to the initial position, and then the system power is turned off to complete the processing.

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