WO2023137820A1

WO2023137820A1 - Abrasive particle-assisted laser electrolysis self-coupling collaborative alignment drilling method and system

Info

Publication number: WO2023137820A1
Application number: PCT/CN2022/077233
Authority: WO
Inventors: 朱浩; 韩进财; 蒋子宣; 徐坤; 赵斗艳; 张朝阳; 刘洋; 高健
Original assignee: 江苏大学
Priority date: 2022-01-21
Filing date: 2022-02-22
Publication date: 2023-07-27
Also published as: CN114346337A

Abstract

The present invention relates to the field of non-traditional machining. Disclosed are an abrasive particle-assisted laser electrolysis self-coupling collaborative alignment drilling method and system. Short pulse laser "point-scanning" is used to implement etching at a specified position on the upper surface of a semiconductor material, and cavitation of the laser in a solution is used to drive abrasive particles to impact and scratch the surface under machining, thereby improving the quality of the surface; moreover, laser irradiation induces generation of a local conductivity enhancement region in the material, and an instantaneous localized conductive channel through which a current preferentially passes is formed; on the back of the semiconductor material, electrolytic machining of a laser scanning position is carried out by using a cathode needle tube, an electrolyte with the abrasive particles is ejected from the cathode needle tube at a certain pressure, and a passivation layer on a lower surface of the semiconductor material is damaged by an impact action of the abrasive particles, so that electrolysis is continuously and efficiently performed in the local conductivity enhancement region, and micropore pairs at corresponding positions are formed on the upper surface and the lower surface of the semiconductor material. According to the present invention, a micropore structure having good surface quality and strict correspondence between upper and lower positions may be obtained.

Description

Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling method and system

technical field

The invention relates to the field of special processing, in particular to an abrasive grain-assisted laser electrolysis self-coupling cooperative alignment drilling method and system for structures such as tiny slits, holes, and grooves.

Background technique

Semiconductor materials represented by silicon and germanium have been widely used in integrated circuits, solar cells, micro-electromechanical systems and other fields. High-efficiency, precise, and fine-grained application scenarios have put forward higher requirements for high-quality micromachining of such materials. Taking integrated circuit manufacturing as an example, through-silicon via (TSV) technology is a new technical solution for interconnection of stacked chips in three-dimensional integrated circuits. It can make chips stacked in the three-dimensional direction with the highest density, the interconnection lines between chips The shortest, the smallest size, and greatly improve the performance of chip speed and low power consumption, it has become the most eye-catching technology in electronic packaging technology. Through-hole processing on the wafer is the core of TSV technology. Currently, there are two main technologies for through-hole processing, namely deep reactive ion etching DRIE and laser drilling. DRIE is an ion-enhanced chemical reaction. The etching system uses an RF-powered plasma source to obtain ions and chemically reactive groups. After being accelerated by an electric field, it impacts the wafer with a strong direction, and achieves high-speed etching along the specified direction in the unprotected area. At the same time, additional gases are introduced to passivate the side walls of the protective holes to obtain a highly anisotropic etching effect. However, in the above etching, as the etching depth increases, it is difficult to discharge part of the reactants and products formed in the silicon deep holes in time, resulting in large damage to the surface, pollution, difficulty in forming fine patterns, and high cost.

Laser drilling does not require a mask, and avoids the process steps of photoresist coating, photolithography exposure, development and degumming, and has made great progress. However, laser drilling also has its disadvantages. For example, if the material melts and then solidifies rapidly, it is easy to form spherical nodules on the surface of the through hole; the inner wall of the through hole is rough, making it difficult to deposit a continuous insulating layer; the subsurface of the inner wall of the through hole is thermally damaged, which affects the reliability of the hole after filling; the dimensional accuracy of the through hole is low. Therefore, laser drilling cannot alone meet the requirements of through-hole processing with smaller aperture and high depth-to-diameter ratio in the future.

After searching the existing technologies, it was found that the Chinese Patent Publication No. CN111682574A discloses a method and device for forming vertical through-holes in semiconductors, which realizes the processing of vertical through-holes in semiconductors through micro-spark discharge, micro-electrochemical finishing and sidewall passivation processes. However, in this method, three processes are used in sequence, and the steps are cumbersome, and there is no discussion on the processing of group holes. The Chinese Patent Publication No. CN113146066A discloses a laser electrochemical backside synergistic micromachining method for semiconductor materials. This method uses a needle jet electrolyte as the cathode, and the positive electrode utilizes the forward laser thermal effect to localize and improve the conductivity of semiconductor materials such as silicon and germanium, forming a localized to point channel through which current preferentially passes, thereby realizing localized electrolysis on the back of the material. However, due to the phenomenon of thermal diffusion, electrolytic stray corrosion and surface passivation, it is difficult to process high-quality deep holes with large depth-to-diameter ratio.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention is based on the characteristic that the conductivity of semiconductor materials increases with the increase of temperature. By using short-pulse laser "spot scanning" to induce localized conductivity enhancement areas at several designated positions on the upper surface of the material, an instantaneous localized conductive channel through which current preferentially passes is formed, and a mixed liquid with abrasive particles is introduced to scratch the passivation layer with abrasive grains on the "spot scanning" area of the material; at the same time, electrolytic processing is introduced on the back of the material using a cathode needle tube, and the laser scanning position is ensured to correspond to the position of the cathode needle through the preliminary knife setting step. The position where the conductivity is localized and enhanced realizes high-efficiency electrochemical anodic dissolution. The electrolyte mixed with abrasive grains in the needle is ejected at a certain pressure and stabilized. The impact of the abrasive grains is used to destroy the passivation layer on the lower surface of the semiconductor material and realize the real-time conduction of the circuit between the cathode and the anode, ensuring that the electrolytic reaction is carried out efficiently in the area of enhanced electrical conductivity. The jet flow can take away the bubbles and impurities generated by the reaction. Processing, so as to obtain high-quality electrolytic machining micro-holes/pits, and the micro-hole processing efficiency is high, the thermal damage is small, the surface quality is good, and the semiconductor material can also be moved to achieve group holes.

The present invention achieves the above-mentioned technical purpose through the following technical means.

Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling method, using pulsed laser to achieve etching at a designated position on the upper surface of a semiconductor material, and at the same time, the pulsed laser generates plasma in the abrasive-containing electrolyte and the processing area, causing strong cavitation, driving the micro-abrasive particles to impact and scratch the processing area and the nearby surface; at the same time, the pulsed laser induces a localized conductivity enhancement area at the processing position on the upper surface of the semiconductor material through photothermal and photoelectric effects, forming a transient localized conductive channel through which current preferentially passes; Needle tube electrolytic machining laser scans the corresponding position, and the electrolyte with abrasive particles is ejected from the cathode needle tube at a certain pressure, and the passivation layer on the lower surface of the semiconductor material is destroyed by the impact of the abrasive particles, so that the electrolytic reaction continues in the local conductivity enhancement area, and finally micropore pairs corresponding to the positions can be formed on the upper surface and the lower surface of the semiconductor material.

In the above scheme, the laser is irradiated on the upper surface of the semiconductor material, and the semiconductor material is used as an anode to connect with the positive pole of the DC pulse power supply; the negative pole of the DC pulse power supply is connected to the cathode needle tube, and the electrolyte with abrasive particles is introduced to the laser irradiation position on the upper surface of the semiconductor material through the conical tube in the form of a constant pressure jet; the cathode needle tube is arranged on the lower surface of the semiconductor material, and the electrolyte with abrasive particles is introduced into the gap between the semiconductor material and the cathode needle tube in the form of a constant pressure jet through the cathode needle tube.

In the above solution, the semiconductor material is a semiconductor material whose electrical conductivity increases with temperature; the cathode needle is inclined or vertically opposite to the semiconductor material.

An abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system includes a laser processing system, a stable micro-abrasive jet generation system, an electrolytic processing system, and a motion control system; the laser processing system is used to provide energy for processing semiconductor materials; the stable micro-abrasive jet generation system is used to provide electrolytes with micro-abrasive particles for cathode needle tubes and tapered tubes; the electrolytic processing system is used for electrolytic processing of semiconductor materials;

In the above solution, the stable micro-abrasive jet generation system includes an inner tank, an outer tank, a cathode needle, a high-pressure spring hose, a first one-way valve, an abrasive grain tank, a mixing chamber, a second one-way valve, an electrolyte cylinder, a piston, a piston rod, a servo motor, a shaft coupling, a first support seat, a ball screw, a slider, a second support seat, an electrolyte tank, a filter, a third one-way valve, and a throttle valve;

The output end of the servo motor is connected with the ball screw through a coupling, and the two ends of the ball screw are respectively supported by the first support seat and the third one-way valve. The ball screw is used to drive the slider. One end of the piston rod is hinged on the slider. The piston connected to the other end of the piston rod is used to compress the electrolyte cylinder. The output end of the electrolyte cylinder is provided with a second check valve. The tube is connected to the conical tube, and the flow rate of the mixed liquid in the conical tube is adjusted by the throttle valve; the electrolyte tank is also connected to the third one-way valve, and the third one-way valve flows the excess electrolyte into the electrolyte tank after being filtered by the filter; there is an overflow pipe on the edge of the space between the inner tank and the outer tank, which is used for the mixed solution to be discharged into the recovery tank in time.

The above solution also includes a clamping device, which can be divided into a semiconductor material clamping device and a tapered tube clamping device; the semiconductor material clamping device is used to guide and position the semiconductor material; the clamping device includes a hexagon socket bolt, a flexible pressure piece and a rubber washer; one end of the hexagon socket bolt is arranged on the lower end surface of the inner groove, and a flexible pressure piece and a rubber washer are sequentially installed on the hexagon socket bolt; For water leakage, the rubber gasket on the lower surface can also avoid hard contact between the semiconductor material and the inner tank, and play a protective and buffering role; the tapered tube clamping device is a laser fixed rubber tube device, which supports and adjusts the jet flow direction of the tapered tube.

In the above scheme, the motion control system includes a cathode motion control system and an anode motion control system; the cathode motion control system includes a sensitivity pressure sensor, a Z-axis fine-tuning lifter and a computer; the semiconductor material is placed on the lower end surface of the inner tank, and a through hole is provided at the position where the semiconductor material is placed on the lower end surface of the inner tank, and the cathode needle tube passes through the through hole; When it is large, the sensitivity pressure sensor has pressure perception, and the computer receives the pressure signal of the sensitivity pressure sensor and feeds back to the Z-axis fine-tuning lifter to make corresponding actions; the Z-axis fine-tuning lifter can follow the change of the cathode needle tube processing position and change its position and fix it; the anode motion control system includes an adjustable rod frame and a computer;

In the above solution, the electrolytic processing system includes an inner tank, an outer tank, a recovery tank, an electrolyte, a current probe, an oscilloscope, and a DC pulse power supply; the electrolyte emitted by the cathode needle tube returns to the inner tank, and the electrolyte finally flows to the recovery tank; the semiconductor material is connected to the positive pole of the DC pulse power supply; the negative pole of the DC pulse power supply is connected to the cathode needle tube; the current probe is used to detect whether there is current, and the oscilloscope is used to display the current situation.

In the above scheme, by controlling the feeding speed of the cathode needle tube and specifying the deep dwell time, holes with a cavitation structure can be drilled on the lower surface of the semiconductor material; by fine-tuning the placement angle of the semiconductor material, an oblique hole structure can be drilled.

In the above scheme, the cathode needle tube is coated with an insulating layer on the outside except the position of the needle head, and is coated with a wear-resistant coating on the inside; the electrolyte is a neutral or acidic solution; the abrasive particles are made of insulating materials; the laser is a nanosecond pulse laser or a picosecond pulse laser.

Beneficial effect:

1. Aiming at the problem of high-quality hole processing in semiconductor materials such as monocrystalline silicon, it is proposed to use short-pulse laser "spot scanning" strategy to induce localized conductivity-enhanced regions at several designated positions on the upper surface of the material to form instantaneous localized conductive channels through which current preferentially passes; at the same time, the cathode needle tube is used to introduce electrolytic processing on the back of the material, and the laser scanning position corresponds to the position of the cathode needle through the previous knife-setting step, and then high-efficiency electrochemical anodic dissolution is achieved at the position where the localized conductivity is enhanced. At the same time, the impact of abrasive particles in the electrolyte jet is used to destroy the passivation layer on the lower surface of the semiconductor material, realizing real-time conduction of the circuit between the cathode and the anode, ensuring that the electrolytic reaction is carried out efficiently in the area of enhanced conductivity. The jet can take away the bubbles and impurities generated by the reaction. At the same time, the impact of micro-abrasive particles can remove the oxide adhesion generated during the electrolysis process in real time, achieve the effect of abrasive polishing, and obtain high-quality micropores/pits on the lower surface; adjust the laser beam parameters on the upper surface to achieve etching at the specified position on the upper surface. Plasma is generated in the area, accompanied by bubble generation, expansion, and rupture to produce strong cavitation, which induces strong micro-jet flow near the processing area, and then drives the micro-abrasive particles to impact and micro-scratch the processing area and nearby surfaces, thereby reducing the adhesion of slag near the laser processing area on the upper surface, preventing remelting accumulation of the cut, improving the quality of the processing structure, and forming micropore pairs that are strictly corresponding to the upper and lower surfaces.

2. The method of the present invention can efficiently and high-quality prepare micropore pairs with strict corresponding upper and lower positions. The lower micropores are obtained by electrolytic processing, and the upper micropores are obtained by laser etching and scratched by micro-abrasive particles to improve the surface quality. In addition, by adjusting the processing parameters reasonably, the thickness of the micropore to the intermediate material can be controlled at an extremely thin level, which has potential application value in the fields of micro-electromechanical systems, sensing and detection, etc.

3. The method of the present invention has high feasibility, and for group-hole pair processing, laser electrolytic self-coupling cooperative processing without tool loss can be realized by simply moving the semiconductor material to the next processing point without large adjustment of laser and needle.

4. In the present invention, the semiconductor material is placed obliquely, and high-quality oblique holes can be processed by this method; the needle feed rate can be controlled to realize the processing of the "cavitation structure" inside the semiconductor material.

5. The processing system of the present invention has perfect functions and is easy to assemble and realize. The designed cathode and anode position adjustment device has a simple structure and is easy to install and repair.

6. The function of the sensitivity pressure gauge in the present invention is: when the impact pressure between the cathode needle jet and the lower surface of the semiconductor material is too large, the sensitivity pressure sensor has pressure perception, and the computer receives the pressure signal of the sensitivity pressure sensor and feeds back to the Z-axis fine-tuning lifter to make corresponding actions.

Description of drawings

Fig. 1 is a system schematic diagram of a laser electrolytic self-coupling cooperative drilling method according to an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of the stable jet generation system involved in Fig. 1 of the present invention:

Fig. 3 is a schematic diagram of processing inclined group holes and cavitation structures when the semiconductor material is perpendicular to the cathode needle tube;

Fig. 4 is a schematic diagram of processing inclined group holes and cavity structures when the semiconductor material and the cathode needle tube are inclined.

The reference signs are as follows:

1-laser; 2-laser beam; 3-beam expander; 4-mirror; 5-galvanometer; 6-laser fixed rubber tube; 7-lens; 20-High pressure spring hose; 21-Electrolyte; 22-Current probe; 23-Abutment; 24-Adjustable rod frame; 25-Stable micro-abrasive jet generation system; 26-Oscilloscope; 27-DC pulse power supply; 28-Computer; Rod; 37-servo motor; 38-coupling; 39-first support seat; 40-slider; 41-second support seat; 42-electrolyte tank; 43-filter; 44-third check valve; 45-throttle valve; 46-cavitation structure; 47-insulation layer; 48-extremely thin semiconductor region;

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and so on are based on the orientation or positional relationship shown in the 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, in a specific orientation construction and operation, therefore, should not be construed as limiting the invention.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" 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 an indirect connection through an intermediary, or it can be an internal connection between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Shown in conjunction with accompanying drawing 1-4, a kind of abrasive particle-assisted laser electrolysis self-coupling cooperative drilling system comprises a laser processing system, a stable microabrasive jet generation system 25, an electrolytic processing system and a motion control system; Electrolytic machining of semiconductor material 13; the motion control system is used to control the position of the inner tank 9 and the gap between the cathode needle tube 14 and the semiconductor material 13, including the cathode motion control system and the anode motion control system; the cathode motion control system includes a sensitivity pressure sensor 16, a Z-axis fine-tuning lifter 19 and a computer 28; The sensor 16 is connected, and the Z-axis fine-tuning lifter 19 is used to adjust the distance between the inner wall of the semiconductor material and the cathode needle tube 14. When the impact pressure of the jet of the cathode needle tube 14 and the lower surface of the semiconductor material 13 is too large, the sensitivity pressure sensor 16 has pressure perception. After receiving the pressure signal from the sensitivity pressure sensor 16, the computer 28 feeds back the Z-axis fine-tuning lifter 19 to make corresponding actions; Frame 24 and computer 28; the adjustable rod frame 24 is connected with the inner groove 9, and the adjustable rod frame 24 is used to drive the inner groove 9 to do XYZ three-way precision movement, and complete the group holes on the surface of the semiconductor material 13.

Wherein, the clamping device can be divided into a semiconductor material clamping device and a tapered tube clamping device; the semiconductor material clamping device is used for guiding and positioning the semiconductor material 13; the clamping device includes a hexagon socket bolt 10, a flexible pressure piece 11 and a rubber washer 12; one end of the hexagon socket bolt 10 is arranged on the lower end surface of the inner groove 9, and a flexible pressure piece 11 and a rubber washer 12 are sequentially installed on the hexagon socket bolt 10; The bolt applies a pre-tightening force to fix the semiconductor material, which can prevent water leakage, and the rubber gasket on the lower surface can also prevent the hard contact between the semiconductor material 13 and the inner groove 9, and play a role of protection and buffering. The tapered tube clamping device is a laser fixing rubber tube device 6 to fix the tapered tube 8, and the laser fixing rubber tube device 6 adjusts the jet flow direction.

The laser processing system includes a laser 1, a laser beam 2, a beam expander 3, a reflector 4, a vibrating mirror 5 and a lens 7; the laser beam 2 emitted by the laser 1 passes through the beam expander 3, changes the optical path through the reflector 4, enters the vibrating mirror 5, and finally irradiates on the semiconductor material 13 through the lens 7, and controls the parameters of the laser beam 2 emitted by the laser 1 through a computer 28.

The electrolytic machining system includes an inner tank 9, an outer tank 17, a recovery tank 19, an electrolyte 21, a current probe 22, an oscilloscope 26, and a DC pulse power supply 27; the electrolyte emitted by the cathode needle tube 14 flows back to the inner tank 9, and the electrolyte finally flows to the recovery tank 19; the semiconductor material 13 is connected with the positive pole of the DC pulse power supply 27; the negative pole of the DC pulse power supply 27 is connected with the cathode needle tube 14; 6 is used to display the current situation.

The stable micro-abrasive jet generation system 25 includes a conical tube 8, an inner tank 9, a cathode needle tube 14, an outer tank 17, a high pressure spring hose 20, a first one-way valve 29, an abrasive grain tank 30, a mixing chamber 31, a second one-way valve 32, an electrolyte cylinder 33, a piston 34, a piston rod 35, a servo motor 37, a coupling 38, a first support seat 39, a ball screw 36, a slider 40, a second support seat 41, and an electrolyte tank 4 2. Filter 43, the third one-way valve 44 and throttle valve 45; the output end of the servo motor 37 is connected with the ball screw 36 through the coupling 38, the two ends of the ball screw 36 are respectively supported by the first support seat 39 and the third one-way valve 44, the ball screw 36 is used to drive the slide block 40 arranged above, the slide block 40 is hinged with one end of the piston rod 35, and the piston 34 connected to the other end of the piston rod 35 is used to compress the electrolyte cylinder 33. The output end of the liquid cylinder 33 is provided with a second one-way valve 32, the output end of the second one-way valve 32 communicates with the mixing chamber 31, the mixing chamber 31 is connected with the abrasive grain tank 30 and the outlet flows to the cathode needle tube 14 and the conical tube 8, wherein the cathode needle tube 14 is communicated with a high pressure spring hose 20 and gives the cathode needle tube 14 certain operational flexibility, the flow rate of the mixed liquid in the conical tube 8 is regulated by the throttle valve 45; the electrolyte cylinder 33 is also connected with the third one-way valve 44, the third one-way valve 44 The excess electrolyte is filtered by the filter 43 and then flows into the electrolyte tank 42; there are overflow pipes on the edge of the space between the inner tank 9 and the outer tank 17, so that the mixed solution can be discharged into the recovery tank 19 in time, and the recovery solutions from different sources in the recovery tank 19 are kept insulated.

The position corresponding to the semiconductor material of the cathode needle tube 14 is the position where group holes are to be punched on the semiconductor material 13; the hole depth of the electrolytically punched group holes in the semiconductor material 13 is controlled by a computer 28, and by controlling the feeding speed of the cathode needle and the specified depth dwell time, the hole of the cavitation structure 44 can be punched on the lower end surface of the semiconductor material 13; by fine-tuning the placement angle of the semiconductor material, an oblique hole structure 49 can be punched.

Combined with Figures 1 and 4, a semiconductor material abrasive-assisted laser electrolysis self-coupling cooperative group hole drilling method, based on the characteristics that the conductivity of semiconductor materials such as silicon increases with temperature, uses short-pulse laser "spot scanning" to induce localized conductivity enhancement areas at certain positions on the upper surface of the material to form instantaneous localized conductive channels through which current preferentially passes; at the same time, electrolytic processing is introduced on the lower surface of the semiconductor material 13 using a cathode needle tube 14 with an outer wall insulation treatment, and the laser scanning position corresponds to the position of the cathode needle through the preliminary knife setting step. Realize high-efficiency electrochemical anodic dissolution at the position where the conductivity is enhanced locally, and realize efficient localized electrolytic processing on the back of the material; the electrolyte in the cathode needle tube 14 is mixed with insulating abrasive particles, and the passivation layer on the lower surface of the semiconductor material 13 is destroyed by the impact of the abrasive particles to realize real-time conduction of the circuit between the cathode and the anode, ensuring that the electrolysis reaction is carried out efficiently in the region where the conductivity is enhanced. The jet can take away the bubbles and impurities generated by the reaction. Etching can be realized at the designated position on the upper surface. At the same time, the high-energy laser generates plasma in the abrasive grain mixture and the processing area, accompanied by bubble generation, expansion, and rupture to produce strong cavitation, which induces strong micro-jet flow near the processing area, which in turn drives the micro-abrasive particles to produce impact and micro-scratch on the processing area and the nearby surface, thereby reducing the adhesion of slag near the laser processing area on the upper surface, preventing remelting accumulation of the cut, and improving the quality of the processing structure. Compared with the micropore pair structure; the laser beam 2 emitted by the laser 1 is irradiated on the semiconductor material 13, forming a localized high-temperature region in the semiconductor material, and the conductivity is enhanced locally. The semiconductor material 13 is connected to the positive pole of the DC pulse power supply 25; The flow form is introduced into the gap between the anode semiconductor material 13 and the cathode needle tube 14 to speed up the flow of the electrolyte to take away products such as bubbles, ensure continuous and stable processing, and make the circuit between the cathode and anode conduct. The electrochemical anode dissolution area on the back of the semiconductor material 13 corresponds to the irradiation position of the laser beam 2 for rapid "spot scanning".

The inner tank 9 is fixed by an adjustable rack bar 25, the cathode needle tube bracket 16 is fixed by a Z-axis fine-tuning lifter 19, and the sensitivity pressure sensor 18 is used to detect the jet state of the cathode needle tube 14. The sensitivity pressure sensor 18, the Z-axis fine-tuning lifter 20 and the adjustable rack bar 25 are connected to the computer 26. The adjustable rack bar 25 is lifted and lowered under the control of the computer 29 for cathode installation. When the needle tube 14 is in contact with the semiconductor material 13 or the firing rate is too high, the sensitive pressure sensor 18 has pressure perception, and the computer 26 controls the Z-axis fine-tuning lifter 20 to fine-tune downwards, so that the semiconductor material 9 is slightly separated from the needle, realizing continuous and controllable processing. The next area of the semiconductor material 13 in the inner groove 9 is moved by the adjustable rod frame 25 for processing, and finally the group holes are punched.

The needle tubes in Figures 1 and 3 can also be replaced with other shapes, and the laser scanning path can be changed to obtain structures of different shapes on the back of the semiconductor material.

The laser 1 can be a conventional nanosecond pulse laser or a picosecond/femtosecond ultrashort pulse laser. The use of ultrashort pulse lasers helps to concentrate the temperature field in the material, which can further enhance the localization of the electrolytic machining of the lower surface of the material and improve the processing quality.

The electrolyte solution can be a neutral or acidic solution with an appropriate concentration, and the appropriate solution concentration can be selected from 10% to 30%.

The abrasive particles can be insulating material particles with appropriate particle size, and the content of abrasive particles in the jet can be adjusted according to actual needs.

A current probe 22 is arranged between the oscilloscope 27 and the adjustable pulse power supply 28, and the oscilloscope 27 is connected to the current probe 22 to provide an intuitive waveform diagram. The addition of the adjustable power supply 28 makes the processing more precise, and the recording of pulse and current and voltage signals allows the device to quickly make adjustments with the laser, so that the processing process can be carried out efficiently.

This embodiment is a laser electrolysis self-coupling cooperative group drilling processing system for semiconductor materials. The laser 1 outputs the laser beam 2, the diameter of the laser beam is enlarged by the beam expander 3, the direction is adjusted by the reflector 4, and the movement form of the beam is controlled by the vibrating mirror 5. Finally, after being focused by the lens 7, it is irradiated to the surface of the semiconductor material 13, and the conductivity of the designated position in the semiconductor material 13 is improved locally. The generation of the laser beam 2 and the movement of the vibrating mirror 5 are all controlled by the computer 29 .

2, the servo motor 37 drives the ball screw 36 to rotate through the coupling 38, and the two ends of the ball screw 36 are supported by the first support seat 39 and the second support seat 36; the rotation of the ball screw 36 is converted into the linear motion of the piston rod 35 through the slider 40 matched with the ball screw 36, thereby pushing the electrolyte in the electrolyte tank 42 to output at a constant speed. The electrolyte flows into the mixing chamber 31 through the second one-way valve 29, and the abrasive grains from the abrasive grain tank 30 flowing through the first one-way valve 29 flow into the mixing chamber at the same time, and after mixing evenly, they form stable and constant pressure jets in the cathode needle tube 14 and the tapered tube 8 respectively. The second one-way valve 29 and the third one-way valve 44 can cooperate with the forward and reverse movement of the ball screw 36 to realize the electrolyte output and intake. When the servo motor 32 drives the piston rod 35 to move forward through the ball screw 36, the second one-way valve 29 is opened, the third one-way valve 44 is closed, and the electrolyte enters the hose under the push of the piston 29; In the process of forming a stable constant-pressure jet flow at the shape tube 8, the flow rate of the needle and the flow direction of the tapered tube is adjusted by using the throttle valve 45 of the flow direction of the tapered tube to realize the controllable flow rate of the jet.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific examples" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with this embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be construed as limiting the present invention. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principle and purpose of the present invention.

Claims

A method for abrasive grain-assisted laser electrolysis self-coupling synergistic alignment drilling, characterized in that pulsed laser is used to achieve etching at a designated position on the upper surface of a semiconductor material (13), and at the same time, the pulsed laser generates plasma in the abrasive grain-containing electrolyte (21) and in the processing area, causing strong cavitation, driving the micro abrasive grains to impact and scratch the processing area and the nearby surface; at the same time, the pulsed laser induces a localized conductivity enhanced area at the upper surface of the semiconductor material (13) through photothermal and photoelectric effects, forming a preferential passage of current Instantaneously localize the conductive channel; at the same time, use the cathode needle tube (14) to electrolytically process the laser to scan the corresponding position on the lower surface of the semiconductor material (13), and the electrolyte solution (21) with abrasive particles is injected from the cathode needle tube (14) at a certain pressure, and the passivation layer on the lower surface of the semiconductor material (13) is destroyed by the impact of the abrasive particles, so that the electrolytic reaction continues in the local conductivity enhancement area, and finally micropore pairs (48) corresponding to the positions can be formed on the upper surface and the lower surface of the semiconductor material (13).
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling method according to claim 1, it is characterized in that, laser radiation is on semiconductor material (13) upper surface, semiconductor material (13) joins with the positive pole of DC pulse power supply (27) as anode; The cathode needle tube (14) is arranged on the lower surface of the semiconductor material (13), and the electrolyte solution (21) with abrasive particles is introduced into the gap between the semiconductor material (13) and the cathode needle tube (14) in the form of a constant-pressure jet through the cathode needle tube (14).
The method for abrasive grain-assisted laser electrolytic self-coupling cooperative alignment drilling according to claim 1, wherein the semiconductor material (13) is a semiconductor material whose conductivity increases with temperature; the cathode needle tube (14) is inclined or vertically opposite to the semiconductor material (13).
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system, characterized in that it includes a laser processing system, a stable micro-abrasive jet generation system (25), an electrolytic processing system and a motion control system; the laser processing system is used to provide energy for processing semiconductor materials (13); the stable micro-abrasive jet generation system (25) is used to provide electrolyte (21) with micro-abrasive particles for cathode needle tubes (14) and tapered tubes (8); the electrolytic processing system is used for electrolytic processing of semiconductor materials (13) ; The motion control system is used to adjust the positional relationship between the semiconductor material (13) and the cathode needle tube (14).
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that, the stable micro-abrasive jet generation system (25) includes an inner tank (9), a cathode needle tube (14), an outer tank (17), a high pressure spring hose (20), a first one-way valve (29), an abrasive grain tank (30), a mixing chamber (31), a second one-way valve (32), an electrolyte cylinder (33), a piston (34), a piston rod (3 5), servo motor (37), coupling (38), first support seat (39), ball screw (36), slider (40), second support seat (41), electrolyte tank (42), filter (43), third one-way valve (44) and throttle valve (45);

The output end of described servomotor (37) is connected with ball screw (36) by coupling (38), and ball screw (36) two ends are respectively supported by first supporting base (39) and the 3rd one-way valve (44), and ball screw (36) is used for driving slide block (40), and an end of piston rod (35) is hinged on the described slide block (40), and the piston (34) that the other end of piston rod (35) is connected is used for compressing electrolyte cylinder (3 3), the output end of the electrolyte cylinder (33) is provided with a second one-way valve (32), the output end of the second one-way valve (32) communicates with the mixing chamber (31), and the mixing chamber (31) is connected with an abrasive grain tank (30), which can inject abrasive grains into the mixing chamber (31) as required; the outlet of the mixing chamber (31) communicates with the cathode needle tube (14) and the tapered pipe (8), and the flow rate of the mixed liquid in the tapered pipe (8) is regulated by the throttle valve (45); (33) is also connected with the 3rd one-way valve (44), and the 3rd one-way valve (44) flows in the electrolytic solution tank (42) after unnecessary electrolytic solution is filtered through filter (43); The space edge of described inner tank (9) and outer tank (17) has overflow pipe, is used for mixed solution and is discharged into recovery tank (18) in time.
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that it also includes a clamping device, the clamping device can be divided into a semiconductor material clamping device and a tapered tube clamping device; the semiconductor material clamping device is used for guiding and positioning the semiconductor material (13); the semiconductor material clamping device includes a hexagon socket bolt (10), a flexible pressing piece (11) and a rubber washer (12); A flexible pressing piece (11) and a rubber washer (12) are sequentially installed on the inner hexagonal bolt (10); the rubber washer (12) is placed on the upper and lower sides of the semiconductor material (13) respectively, and the pre-tightening force is applied through the bolt to fix the semiconductor material (13) to prevent water leakage. The rubber washer (12) on the lower surface can also prevent the hard contact between the semiconductor material (13) and the inner groove (9) and play a protective and buffering role; The laser fixing rubber tube device (6) supports and adjusts the jet flow direction of the tapered tube (8).
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that, the motion control system includes a cathode motion control system and an anode motion control system; the cathode motion control system includes a sensitivity pressure sensor (16), a Z-axis fine-tuning lifter (19) and a computer (28); the semiconductor material (13) is placed on the lower end surface of the inner groove (9), and a through hole is provided at the position where the semiconductor material (13) is placed on the lower end surface of the inner groove (9), through which the cathode needle tube (14) passes Through hole; the Z-axis fine-tuning lifter (19) is connected with the sensitivity pressure sensor (16), and the Z-axis fine-tuning lifter (19) is used to adjust the distance between the inner wall of the semiconductor material and the cathode needle tube (14). When the impact pressure of the cathode needle tube (14) jet flow and the lower surface of the semiconductor material (13) is too large, the sensitivity pressure sensor (16) has pressure perception, and the computer (28) feeds back the pressure signal of the sensitivity pressure sensor (16) to the Z-axis fine-tuning lifter (19) to make corresponding actions The Z-axis fine-tuning lifter (19) can change position and be fixed following the change of the processing position of the cathode needle tube (14); the anode motion control system includes an adjustable rod frame (24) and a computer (28); the adjustable rod frame (24) is connected with the inner groove (9), and the adjustable rod frame (24) is used to drive the inner groove (9) for XYZ three-way precision movement, and completes group holes on the surface of the semiconductor material (13).
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that, the electrolytic machining system includes an inner tank (9), an outer tank (17), a recovery tank (18), an electrolyte (21), a current probe (22), an oscilloscope (26) and a DC pulse power supply (27); the electrolyte solution ejected from the cathode needle tube (14) flows back to the inner tank (9), and the electrolyte finally flows to the recovery tank (18); (13) is connected with the positive pole of DC pulse power supply (27); The negative pole of DC pulse power supply (27) is connected with cathode needle tube (14); Described current probe (22) is used for detecting whether there is electric current, and oscilloscope (26) is used for showing current situation.
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that, by controlling the feeding speed of the cathode needle tube (14) and specifying the dwell time at the depth, holes with a cavitation structure (46) can be drilled on the lower surface of the semiconductor material (13); by fine-tuning the placement angle of the semiconductor material (13), oblique hole structures (49) can be drilled.
Abrasive-assisted laser electrolysis self-coupling cooperative alignment drilling system according to claim 4, characterized in that, the cathode needle tube (14) is coated with an insulating layer (47) on the outside except the position of the needle head, and the inside is coated with a wear-resistant coating; the electrolyte is a neutral or acidic solution; the abrasive grains are made of insulating materials; the laser (1) is a nanosecond pulse laser or a picosecond pulse laser.