Photoelectrochemical laser direct writing etching device and maskless etching processing method

Abstract

The invention provides a photoelectrochemical laser direct writing etching device and a maskless etching processing method. The photoelectrochemical laser direct writing etching device comprises a laser light source, an acoustic optical modulator, a reflector, a lens, a spatial filter module, a filter objective lens, a dichroscope-beam splitter and a focusing objective lens. An illumination light source, a spectroscope and an industrial camera; the motion controller is used for moving the sample table; the moving sample table is used for placing a wafer to be etched; laser generated by the laser light source is turned by the first reflector and the second reflector, sequentially passes through the filter objective lens and the spatial filter module along a second straight line, then passes through the third reflector and the fourth reflector and is emitted to the dichroscope-beam splitter, and the reflected laser sequentially passes through the dichroscope-beam splitter and the focusing objective lens and is emitted to the spatial filter module along a second straight line. And the wafer to be etched is emitted to the moving sample stage. The method is a photoelectrochemical laser direct writing method which is free of mask, high in efficiency, low in cost and easy and convenient to operate, and manufacturing of a complex free-form surface micro-optical element can be achieved.

Description

Technical Field

[0001] The invention relates to the field of photoelectrochemical laser direct writing, and in particular to a photoelectrochemical laser direct writing etching device and a maskless etching processing method. Background Art

[0002] Semiconductor material free-form surface micro-optical components have the advantages of small size, light weight, flexible design, and efficient optical performance, and have a wide range of potential applications in artificial intelligence, information processing, aerospace, biomedicine, laser technology, etc. However, it is difficult to realize the manufacture of three-dimensional free-form surface micro-optical components with complex morphology.

[0003] Photolithography is a key core technology in semiconductor manufacturing. Photolithography refers to the preparation of patterns on a photosensitive substrate by exposing the designed graphics. The process flow of photolithography mainly includes steps such as coating, exposure, development, and etching, and the technical complexity is relatively high. In the existing photolithography technology, mask lithography and maskless lithography are the two mainstreams. Although mask lithography is a mature technology, its smaller feature size means expensive mask processing costs, and the characteristics of the mask determine the immutability of the mask, which lacks versatility and flexibility.

[0004] In contrast, maskless lithography has attracted much attention for its high flexibility and variability, and has become a hot topic in current research. Laser direct writing technology is one of the fastest-growing maskless lithography technologies. It reduces the energy beam to the micrometer and nanometer levels, and then moves the substrate or energy beam to modify the photosensitive material at different positions on the substrate, thereby causing the difference in the dissolution of the exposed part and the unexposed part in the special developer, and then removes the patterned part. Although maskless lithography has made significant progress in improving lithography resolution and can achieve nanometer-level lithography resolution, its exposure efficiency is relatively low and the requirements for the working environment are extremely high, resulting in high overall cost. Therefore, in order to promote the further development of free-form micro-optical components of semiconductor materials and improve the integration of micro-nano manufacturing, it is particularly important to develop a maskless lithography technology that is simple to use, efficient, low-cost and flexible. Summary of the invention

[0005] In view of the above-mentioned problems that currently exist, the purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method, which can realize the manufacture of free-form surface micro-optical elements through maskless, photoresist-free, high-efficiency, low-cost, and easy-to-operate photoelectrochemical laser direct writing.

[0006] In order to solve the above technical problems, the present invention provides a photoelectrochemical laser direct writing etching device, including: a laser processing optical path, a microscope and monitoring observation optical path, a host computer control system, and an electric displacement platform; wherein:

[0007] The laser processing optical path comprises a laser light source (1), an acousto-optic modulator (2), a first reflector (3), a filter objective lens (4), a spatial filter module (5), a second reflector (6), a third reflector (7), a fourth reflector (8), a dichroic mirror-beam splitter (9), and a focusing objective lens (10);

[0008] The microscope and observation light path comprises an illumination light source (11), a first lens (12), a second lens (13), a beam splitter (14), a third lens (15), and an industrial camera (16);

[0009] The electric displacement platform comprises a motion controller (17) and a motion sample stage (18);

[0010] The moving sample stage is used to place the electrolytic cell (22) and the wafer (19) to be etched, and the wafer (19) to be etched is placed at the bottom of the electrolytic cell (22);

[0011] The control system comprises a host computer (20) and a data acquisition card (DAQ) (21);

[0012] The laser light generated by the laser light source (1) passes through an acousto-optic modulator (2), is deflected by a reflector (3), and then passes through a filter objective lens (4) and a spatial filter module (5) in sequence along a second straight line. The laser light then passes through a first reflector (6), a second reflector (7), and a third reflector (8), and then is emitted to a dichroic mirror-beam splitter (9). The reflected laser light then passes through a dichroic mirror-beam splitter (9) and a focusing objective lens (10) in sequence, and is emitted to a wafer (19) to be etched on a moving sample stage (18);

[0013] The illumination light generated by the illumination light source (11) is emitted to a wafer (19) to be etched on a moving sample stage (18) through a first lens (12), a second lens (13), a beam splitter (14), a dichroic mirror-beam splitter (9), and a focusing objective lens (10) in sequence, and the illumination light reflected by the wafer (19) to be etched is emitted to an industrial camera (16) through a focusing objective lens (10), a dichroic mirror-beam splitter (9), a beam splitter (14), and a third lens (15) in sequence;

[0014] The host computer (20) is connected to a data acquisition card (DAQ) (21), and the laser light source (1), the acousto-optic modulator (2), the moving sample stage (18), and the industrial camera (16) are all communicatively connected to the host computer (20).

[0015] In a preferred embodiment, the laser light source (1), the acousto-optic modulator (2), and the first reflector (3) are arranged in sequence along a first straight line in the horizontal direction;

[0016] The first reflector (3), the filter objective lens (4), the spatial filter module (5), and the second reflector (6) are arranged in sequence along a second straight line in the horizontal direction; the second reflector (6) and the third reflector (7) are arranged in sequence horizontally along a second straight line perpendicular to the horizontal direction; the third reflector (7) and the fourth reflector (8) are arranged in sequence along a first straight line in the gravity direction; the fourth reflector (8) and the dichroic mirror-beam splitter (9) are arranged in sequence along a third straight line in the horizontal direction; the dichroic mirror-beam splitter (9), the focusing objective lens (10), and the moving sample stage (18) are arranged in sequence along the second straight line in the gravity direction.

[0017] In a preferred embodiment, the industrial camera (16), the third lens (15), and the beam splitter (14) are arranged in sequence along a second straight line in the direction of gravity;

[0018] The industrial camera (16), the third lens (15), and the beam splitter (14) are located on the upper side of the dichroic mirror-beam splitter (9), the focusing objective lens (10), and the moving sample stage (19); the illumination light source (11), the first lens (12), the second lens (13), and the beam splitter (14) are arranged in sequence along a fourth straight line in the horizontal direction.

[0019] In a preferred embodiment, an active focusing program is also included. The active focusing program adjusts the distance between the wafer to be etched (19) and the focusing objective lens (10) by moving the wafer to be etched in the Z direction through the moving sample stage according to the clarity of the surface image of the wafer to be etched (19) collected by the industrial camera (16) via the host computer (20) according to the image clarity evaluation function.

[0020] In a preferred embodiment, the moving sample stage (18) comprises a high-precision piezoelectric ceramic displacement stage, which is used to carry the wafer (19) to be etched and drive the wafer (19) to be etched to move in the XY direction.

[0021] The present invention also provides a maskless etching method, using the photoelectrochemical laser direct writing etching device as described above, the maskless etching method comprises the following steps:

[0022] Step 1: Start the laser light source (1), the acousto-optic modulator (2), the motion controller (17), the industrial camera (16), and the host computer (20);

[0023] Step 2: placing the wafer to be etched (19) at the bottom of a photoelectrochemical system electrolytic cell (22), and then placing the electrolytic cell (22) on a sample stage (18) that moves horizontally in the XY direction;

[0024] Step 3: injecting a photoelectrochemical etching solution into the electrolytic cell (22) so that the etching solution covers the wafer (19) to be etched;

[0025] Step 4: Control the focusing objective lens (10) to approach the wafer to be etched (19), observe the clarity of the surface image of the wafer to be etched (19) collected by the industrial camera (16) through the host computer (20), and adjust the distance between the focusing objective lens (10) and the wafer to be etched (19) in the Z direction until the image is clear and focusing is completed;

[0026] Step 5: According to the pre-processed free-form surface 3D morphology data (x i ,y i , z i ) and calculate the processing data (x i ,y i , E i ), where E i The focused laser light source (1) on the surface of the wafer (19) to be etched moves to (x i ,y i ) when the corresponding laser light source (1) power control voltage signal; the proportional relationship is the pre-processed free-form surface three-dimensional morphology height data z i With laser light source (1) power intensity I i The corresponding relationship between the ratio of the etching scanning speed v is expressed as The calculation is performed, wherein the value range of a1 is 0.001 to 10, the value range of b1 is 0.001 to 10; the value range of the power intensity I of the laser light source (1) is 10 -4 ~10 6 W / cm 2 The laser light source (1) has a power intensity of I i The corresponding control voltage signal E i The corresponding relationship between them is expressed as E i =a2×I i +b2 is used for calculation, where the value range of a2 is 0.001 to 10, and the value range of b2 is 0.001 to 10;

[0027] Step six: The focused laser light source on the surface of the wafer (19) to be etched performs a scanning motion along a preset trajectory relative to the wafer (19) to be etched, and the power intensity and scanning motion trajectory of the laser light source (1) are modulated in real time according to the calculated processing data (xi, yi, Ei), and finally a predetermined free-form surface three-dimensional micro-nano structure is processed on the wafer (19) to be etched.

[0028] In a preferred embodiment, in step 2, the material of the wafer (19) to be etched is silicon, germanium, gallium arsenide, gallium phosphide, indium phosphide, zinc sulfide or cadmium telluride, or a combination of at least two of the above materials.

[0029] In a preferred embodiment, in step three, the photoelectrochemical etching solution is a mixture of an etchant and a supporting electrolyte; the etchant is at least one of FeCl3, HNO3, HF, KMnO4, K2S2O8, and bromide, and the concentration of the etchant is 0.001-0.3 mol / L; the supporting electrolyte is at least one of hydrochloric acid, sulfuric acid, phosphate, and L-cystine, and the concentration of the supporting electrolyte is 0.1-2 mol / L; the mass ratio of the etchant to the supporting electrolyte is 1:1-1:100.

[0030] In a preferred embodiment, in step 4, the industrial camera (16) collects images in real time and sends the collected images to the host computer (20). The host computer (20) processes the images and monitors the photoelectrochemical laser direct writing process.

[0031] In a preferred embodiment, in step 5, the scanning speed of the etching scanning motion is 0.001-10 mm / s:

[0032] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0033] (1) The purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method, which only requires a three-dimensional manipulation device, signal communication and related ancillary facilities to complete the three-dimensional morphology processing of free-form surfaces. Compared with electron beam lithography and LIGA technology, this method does not require complex equipment and the processing technology is simple and easy.

[0034] (2) The purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method. Compared with the three-beam direct writing technology, this method does not require expensive energy beam equipment and has low cost.

[0035] (3) The purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method. Since it is a photoelectrochemical induced processing, the processing process is carried out in a solution with a mild environment, and the surface and sub-surface damage of the processed workpiece can be avoided.

[0036] (4) The purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method. During the processing, the laser light source has no contact with the wafer to be etched, and the wafer to be etched can avoid mechanical damage. In addition, there are no special requirements for the properties of the wafer to be etched, and hard and brittle materials can be processed.

[0037] (5) The purpose of the present invention is to provide a photoelectrochemical laser direct writing etching device and a maskless etching processing method, which belongs to single exposure and one-time forming, thereby greatly reducing the processing complexity and improving the processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of a photoelectrochemical laser direct writing device according to a specific embodiment of the present invention;

[0039] Figure 2 A schematic diagram of processing steps according to a specific embodiment of the present invention;

[0040] Figure 3 A height map of a three-dimensional structure to be processed in Example 1 according to a specific implementation manner of the present invention;

[0041] Figure 4 This is a data diagram of a machining voltage simulation signal in a machining process in Example 1 according to a specific implementation manner of the present invention;

[0042] Figure 5 The surface morphology of gallium arsenide after processing in Example 1 according to the specific implementation of the present invention is shown in FIG.

[0043] Figure 6 This is a microscope image of the gallium arsenide surface after processing in Example 1 according to a specific embodiment of the present invention.

[0044] Reference numerals

[0045] 1: Laser light source; 2: Acousto-optic modulator; 3: First reflector; 4: Filter objective lens; 5: Spatial filter module; 6: Second reflector, 7: Third reflector, 8: Fourth reflector; 9: Dichroic mirror-beam splitter; 10: Focusing objective lens; 11: Illumination light source; 12: First lens; 13: Second lens; 14: Beam splitter; 15: Third lens; 16: Industrial camera; 17: Motion controller; 18: Motion sample stage; 19: Wafer to be etched; 20: Host computer; 21: Data acquisition card (DAQ); 22: Electrolytic cell. DETAILED DESCRIPTION

[0046] In order to make the technical solutions and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0047] like Figure 1As shown, the present invention provides a photoelectrochemical laser direct writing etching device, which includes a laser light source 1, an acousto-optic modulator 2, a first reflector 3, a filter objective lens 4, a spatial filter module 5, a second reflector 6, a third reflector 7, a fourth reflector 8, a dichroic mirror-beam splitter 9, and a focusing objective lens 10; the microscope and observation light path includes an illumination light source 11, a first lens 12, a second lens 13, a beam splitter 14, a third lens 15, and an industrial camera 16; the electric displacement platform includes a motion controller 17 and a motion sample stage 18; the motion sample stage is used to place a wafer to be etched 19; the control system includes a host computer 20 and a data acquisition card DAQ21.

[0048] Further, combined with Figure 1 As shown, the laser light source 1 and the acousto-optic modulator 2 are arranged in sequence along a first straight line. The generated laser is deflected by the first reflector 3 and passes through the filter objective lens 4 and the spatial filter module 5 in sequence along a second straight line. The laser is then emitted to the dichroic mirror-beam splitter 9 through the second reflector 6, the third reflector 7, and the fourth reflector 8. The reflected laser passes through the dichroic mirror-beam splitter 9 and the focusing objective lens 10 in sequence and is emitted to the wafer 19 to be etched on the moving sample stage 18.

[0049] Further, combined with Figure 1 As shown, the laser light source 1, the acousto-optic modulator 2, and the first reflector 3 are arranged in sequence along a first straight line in the horizontal direction, the first reflector 3, the filter objective lens 4, the spatial filter module 5, and the second reflector 6 are arranged in sequence along a second straight line in the horizontal direction, wherein the second reflector 6 and the third reflector 7 are arranged horizontally and sequentially along a second straight line perpendicular to the horizontal direction; the third reflector 7 and the fourth reflector 8 are arranged in sequence along a first straight line in the gravity direction, wherein the fourth reflector 8 and the dichroic mirror-beam splitter 9 are arranged in sequence along a third straight line in the horizontal direction, and the dichroic mirror-beam splitter 9, the focusing objective lens 10, and the moving sample stage 18 are arranged in sequence along the second straight line in the gravity direction, so as to ensure that a collimated optical path is obtained with uniform energy distribution and a small enough spot size focused on the sample surface.

[0050] Further, combined with Figure 1As shown, the industrial camera CCD16, the third lens 15, and the beam splitter 14 are arranged in sequence along the second straight line in the gravity direction, and the industrial camera CCD16, the third lens 15, and the beam splitter 14 are located on the upper side of the dichroic mirror-beam splitter 9, the focusing objective lens 10, and the moving sample stage 18; the illumination light source 11, the first lens 12, the second lens 13, and the beam splitter 14 are arranged in sequence along the fourth straight line in the horizontal direction; wherein the illumination light generated by the illumination light source 11 is emitted to the wafer 19 to be etched on the moving sample stage 18 through the first lens 12, the second lens 13, the beam splitter 14, the dichroic mirror-beam splitter 9, and the focusing objective lens 10 in sequence, and the illumination light reflected by the wafer 19 to be etched is emitted to the industrial camera CCD16 through the focusing objective lens 10, the dichroic mirror-beam splitter 9, the beam splitter 14, and the third lens 15 in sequence, thereby ensuring that the laser direct writing process can be monitored in real time through the camera CCD, and at the same time making the laser direct writing lithography device sufficiently compact.

[0051] Further, combined with Figure 1 As shown, the photoelectrochemical laser direct writing etching device for three-dimensional micro-nano structure processing also includes an active focusing program. The active focusing program adjusts the distance between the wafer 19 to be etched and the focusing objective lens 10 according to the clarity of the surface image of the wafer 19 to be etched collected by the industrial camera CCD16 via the host computer 20 according to the image clarity evaluation function, so as to ensure real-time focusing and guarantee processing accuracy.

[0052] Further, combined with Figure 1 As shown, the moving sample stage 18 includes a high-precision piezoelectric ceramic displacement stage, which is used to carry the wafer 19 to be etched and drive the wafer 19 to be etched to move in the XY direction, thereby realizing the processing of the preset free-form surface microstructure.

[0053] Further, combined with Figure 1 As shown, the control system includes a host computer 20 and a data acquisition card DAQ21. The host computer 20 is connected to the data acquisition card DAQ21. The laser light source 1, the acousto-optic modulator 2, the moving sample stage 18, and the industrial camera 16 are all communicatively connected to the host computer 20 to ensure mutual communication of optical signals, electrical signals, and parameter signals to achieve coordinated operation of each component.

[0054] like Figure 1 and Figure 2 As shown, this embodiment describes a maskless etching method, using the above-mentioned photoelectrochemical laser direct writing etching device, and the maskless etching method includes the following steps:

[0055] Step 1: Start the laser light source, acousto-optic modulator, motion sample stage, industrial camera, and host computer;

[0056] Step 2: placing the wafer to be etched at the bottom of the electrolytic cell of the photoelectrochemical system, and then placing the electrolytic cell on a sample stage that moves horizontally in the XY direction;

[0057] Step 3: injecting a photoelectrochemical etching solution into the electrolytic cell so that the etching solution covers the wafer to be etched;

[0058] Step 4: Control the focusing objective lens to approach the wafer to be etched, observe the clarity of the surface image of the wafer to be etched collected by the industrial camera through the host computer, and adjust the distance between the focusing objective lens and the wafer to be etched in the Z direction until the image is clear and the focusing is completed;

[0059] Step 5: According to the pre-processed free-form surface 3D morphology data x i ,y i , z i And calculate the processing data x according to the proportional relationship i ,y i , E i , where Ei is the focused laser light source on the surface of the wafer to be etched moving to x i ,y i The corresponding laser light source power control voltage signal;

[0060] Step 6: The focused laser light source on the surface of the wafer to be etched performs a scanning motion along a preset trajectory relative to the wafer to be etched. i ,y i , E i The power intensity of the laser light source and the scanning trajectory are modulated in real time, and ultimately a predetermined free-form surface three-dimensional micro-nano structure is processed on the wafer to be etched.

[0061] Further, combined with Figure 2 As shown, in step 2, the material of the wafer 19 to be etched is silicon, germanium, gallium arsenide, gallium phosphide, indium phosphide, zinc sulfide or cadmium telluride, or a combination of at least two of the above materials. The present invention can select different semiconductor materials for processing according to the specific laser light source wavelength.

[0062] Further, combined with Figure 2 As shown, in step three, the photoelectrochemical etching solution is a mixture of an etchant and a supporting electrolyte; the etchant is at least one of FeCl3, HNO3, HF, KMnO4, K2S2O8, and bromide, and the concentration of the etchant is 0.001-0.3 mol / L; the supporting electrolyte is at least one of hydrochloric acid, sulfuric acid, phosphate, and L-cystine, and the concentration of the supporting electrolyte is 0.1-2 mol / L; the mass ratio of the etchant to the supporting electrolyte is 1:1-1:100. The present invention can select a suitable etching solution for processing according to different wafer materials to be etched.

[0063] Further, combined with Figure 2 As shown, in step 5, according to the pre-processed free-form surface three-dimensional morphology data x i ,y i , z i And calculate the processing data x according to the proportional relationship i ,y i , E i , where E i The focused laser light source on the surface of the wafer to be etched moves to x i ,y i The corresponding laser light source power control voltage signal when the ratio is the pre-processed free-form surface three-dimensional morphology height data z i With laser light source 1 power intensity I i The corresponding relationship between the ratio of the etching scanning speed v is expressed as Calculation is performed, wherein the value range of a1 is 0.001 to 10, the value range of b1 is 0.001 to 10; the value range of the power intensity I of the laser light source 1 is 10 -4 ~10 3 W / cm 2 The power intensity of the laser light source 1 is i The corresponding control voltage signal E i The corresponding relationship between them is expressed as E i =a2×I i + b2 is calculated, wherein the value range of a2 is 0.001 to 10, and the value range of b2 is 0.001 to 10. The present invention selects appropriate parameters according to the specific electrochemical system and the material of the wafer to be etched, and processes the wafer to be etched.

[0064] Further, combined with Figure 2 As shown, in step 5, the movement speed of the etching scanning movement is 0.001-10 mm / s. The present invention can select a suitable scanning movement speed according to different chemical systems and processing efficiencies, and can achieve effective and rapid processing.

[0065] Embodiment 1: Figure 3 A three-dimensional height map to be processed by the present invention is given. Figure 5 The surface morphology of gallium arsenide after processing by the present invention is given. Figure 6 The microscopic image of the gallium arsenide surface after processing by the present invention is given. The processing conditions are: the solution used contains 0.275 mol / L nitric acid and 0.870 mol / L HCl; before processing, the three-dimensional height map to be processed is calculated according to the formula Transformed into processing signal Figure 4; In the Z direction, the moving sample stage is moved to ensure positioning accuracy. The sample stage in this embodiment is a piezoelectric ceramic displacement stage, so that the focusing objective lens approaches the wafer to be etched until it is focused; the moving sample stage is controlled to perform scanning movement in the XY direction relative to the focused laser light source, and the scanning speed is 50μm / s. At the same time, the laser power and the displacement of the moving sample stage are adjusted according to the above-mentioned processing simulation voltage signal diagram; the movement in all directions is completed by the host computer software controlling the motion controller, and the laser light source power change is completed by the host computer software controlling the acousto-optic modulator. After the scanning movement is completed, the focusing objective lens is controlled to be away from the wafer to be etched, and a three-dimensional micro-nano structure consistent with the three-dimensional morphology to be processed can be obtained.

[0066] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A photoelectrochemical laser direct writing etching device, characterized in that: include: Laser processing optical path, microscope and monitoring observation optical path, host computer control system, electric displacement platform; including: The laser processing optical path comprises a laser light source (1), an acousto-optic modulator (2), a first reflector (3), a filter objective lens (4), a spatial filter module (5), a second reflector (6), a third reflector (7), a fourth reflector (8), a dichroic mirror-beam splitter (9), and a focusing objective lens (10); The microscope and observation light path comprises an illumination light source (11), a first lens (12), a second lens (13), a beam splitter (14), a third lens (15), and an industrial camera (16); The electric displacement platform comprises a motion controller (17) and a motion sample stage (18); The moving sample stage is used to place the electrolytic cell (22) and the wafer (19) to be etched, and the wafer (19) to be etched is placed at the bottom of the electrolytic cell (22); The control system comprises a host computer (20) and a data acquisition card (DAQ) (21); The laser light generated by the laser light source (1) passes through an acousto-optic modulator (2), is deflected by a reflector (3), and then passes through a filter objective lens (4) and a spatial filter module (5) in sequence along a second straight line. The laser light then passes through a first reflector (6), a second reflector (7), and a third reflector (8), and then is emitted to a dichroic mirror-beam splitter (9). The reflected laser light then passes through a dichroic mirror-beam splitter (9) and a focusing objective lens (10) in sequence, and is emitted to a wafer (19) to be etched on a moving sample stage (18); The illumination light generated by the illumination light source (11) is emitted to a wafer (19) to be etched on a moving sample stage (18) through a first lens (12), a second lens (13), a beam splitter (14), a dichroic mirror-beam splitter (9), and a focusing objective lens (10) in sequence, and the illumination light reflected by the wafer (19) to be etched is emitted to an industrial camera (16) through a focusing objective lens (10), a dichroic mirror-beam splitter (9), a beam splitter (14), and a third lens (15) in sequence; The host computer (20) is connected to a data acquisition card (DAQ) (21), and the laser light source (1), the acousto-optic modulator (2), the moving sample stage (18), and the industrial camera (16) are all communicatively connected to the host computer (20).

2. The photoelectrochemical laser direct writing etching device according to claim 1, characterized in that: The laser light source (1), the acousto-optic modulator (2), and the first reflector (3) are arranged in sequence along a first straight line in a horizontal direction; The first reflector (3), the filter objective lens (4), the spatial filter module (5), and the second reflector (6) are arranged in sequence along a second straight line in the horizontal direction; the second reflector (6) and the third reflector (7) are arranged in sequence horizontally along a second straight line perpendicular to the horizontal direction; the third reflector (7) and the fourth reflector (8) are arranged in sequence along a first straight line in the gravity direction; the fourth reflector (8) and the dichroic mirror-beam splitter (9) are arranged in sequence along a third straight line in the horizontal direction; the dichroic mirror-beam splitter (9), the focusing objective lens (10), and the moving sample stage (18) are arranged in sequence along the second straight line in the gravity direction.

3. The photoelectrochemical laser direct writing etching device according to claim 1, characterized in that: The industrial camera (16), the third lens (15), and the beam splitter (14) are arranged in sequence along a second straight line in the direction of gravity; The industrial camera (16), the third lens (15), and the beam splitter (14) are located on the upper side of the dichroic mirror-beam splitter (9), the focusing objective lens (10), and the moving sample stage (19); the illumination light source (11), the first lens (12), the second lens (13), and the beam splitter (14) are arranged in sequence along a fourth straight line in the horizontal direction.

4. The photoelectrochemical laser direct writing etching device according to claim 1, characterized in that: The invention also includes an active focusing program, which adjusts the distance between the wafer to be etched (19) and the focusing objective lens (10) by moving the wafer to be etched in the Z direction through the moving sample stage according to the image clarity evaluation function via the host computer (20) and the clarity of the surface image of the wafer to be etched (19) collected by the industrial camera (16).

5. The photoelectrochemical laser direct writing etching device according to claim 1, characterized in that: The moving sample stage (18) comprises a high-precision piezoelectric ceramic displacement stage, which is used to carry the wafer (19) to be etched and drive the wafer (19) to be etched to move in the XY direction.

6. A maskless etching method, characterized in that The photoelectrochemical laser direct writing etching device according to any one of claims 1 to 5 is characterized in that the maskless etching processing method comprises the following steps: Step 1: Start the laser light source (1), the acousto-optic modulator (2), the motion controller (17), the industrial camera (16), and the host computer (20); Step 2: placing the wafer to be etched (19) at the bottom of a photoelectrochemical system electrolytic cell (22), and then placing the electrolytic cell (22) on a sample stage (18) that moves horizontally in the XY direction; Step 3: injecting a photoelectrochemical etching solution into the electrolytic cell (22) so that the etching solution covers the wafer (19) to be etched; Step 4: Control the focusing objective lens (10) to approach the wafer to be etched (19), observe the clarity of the surface image of the wafer to be etched (19) collected by the industrial camera (16) through the host computer (20), and adjust the distance between the focusing objective lens (10) and the wafer to be etched (19) in the Z direction until the image is clear and focusing is completed; Step 5: According to the pre-processed free-form surface 3D morphology data (x i ,y i , z i ) and calculate the processing data (x i ,y i , E i ), where E i The focused laser light source (1) on the surface of the wafer (19) to be etched moves to (x i ,y i ) when the corresponding laser light source (1) power control voltage signal; the proportional relationship is the pre-processed free-form surface three-dimensional morphology height data z i With laser light source (1) power intensity I i The corresponding relationship between the ratio of the etching scanning speed v is expressed as The calculation is performed, wherein the value range of a1 is 0.001 to 10, the value range of b1 is 0.001 to 10; the value range of the power intensity I of the laser light source (1) is 10 -4 ~10 6 W / cm 2 The laser light source (1) has a power intensity of I i The corresponding control voltage signal E i The corresponding relationship between them is expressed as E i =a2×I i +b2 is used for calculation, where the value range of a2 is 0.001 to 10, and the value range of b2 is 0.001 to 10; Step six: The focused laser light source on the surface of the wafer (19) to be etched performs a scanning motion along a preset trajectory relative to the wafer (19) to be etched, and the power intensity and scanning motion trajectory of the laser light source (1) are modulated in real time according to the calculated processing data (xi, yi, Ei), and finally a predetermined free-form surface three-dimensional micro-nano structure is processed on the wafer (19) to be etched.

7. The maskless etching method according to claim 6, characterized in that: In step 2, the material of the wafer (19) to be etched is silicon, germanium, gallium arsenide, gallium phosphide, indium phosphide, zinc sulfide or cadmium telluride, or a combination of at least two of the above materials.

8. The maskless etching method according to claim 6, characterized in that: In step three, the photoelectrochemical etching solution is a mixture of an etchant and a supporting electrolyte; the etchant is at least one of FeCl3, HNO3, HF, KMnO4, K2S2O8, and bromide, and the concentration of the etchant is 0.001-0.3 mol / L; the supporting electrolyte is at least one of hydrochloric acid, sulfuric acid, phosphate, and L-cystine, and the concentration of the supporting electrolyte is 0.1-2 mol / L; the mass ratio of the etchant to the supporting electrolyte is 1:1-1:

100.

9. The maskless etching method according to claim 6, characterized in that: In step 4, the industrial camera (16) collects images in real time and sends the collected images to the host computer (20). The host computer (20) processes the images and monitors the photoelectrochemical laser direct writing process.

10. The maskless etching method according to claim 6, characterized in that: In step five, the scanning speed of the etching scanning motion is 0.001 to 10 mm / s.

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