Fine metal mask laser machining device and machining method therefor

Abstract

The present invention relates to the technical field of laser machining, and in particular to a fine metal mask laser machining device and a machining method therefor. A galvanometer machining head is used for performing galvanometer full travel deflection on an incident laser beam; the galvanometer machining head is mounted on one side of a dynamic focusing module, and a laser head is mounted on the other side of the dynamic focusing module; a laser shaping module is located below the galvanometer machining head; an objective lens switching module is located below the laser shaping module, and several objective lenses having different magnifications are mounted on the objective lens switching module; and an automatic focusing module is located on one side of a third beam combiner. The described structures are integrated; the three-dimensional machining capability of the galvanometer machining head and a dynamic focusing lens, the plane shaping capability of a field lens and the ultra-fine observation and machining capability of an objective lens are all achieved; and the ratio of the focal length of a field lens-like telecentric focusing lens to the focal length of a plano-convex lens-like shaping lens is designed to be about 1: 4, such that it is guaranteed that laser becomes parallel light rays after passing through the plano-convex lens-like shaping lens, and the diameter of a light spot is increased to be 4 times of the original diameter of the light spot.

Description

A fine metal mask laser processing device and processing method thereof Technical Field

[0001] The present invention relates to the technical field of laser processing, in particular to a fine metal mask laser processing device and a processing method thereof. Background Art

[0002] A fine metal mask (FMM) is a tool used to create micro- and nanoscale structures. It is typically made of metal materials such as aluminum or chromium and has highly precise patterns. FMMs are widely used in microelectronics, photonics, biomedicine, and nanotechnology.

[0003] Precision metal masks (FMMs) are core consumables used in organic light-emitting diode (OLED) production. They are only approximately 20 microns thick, but can reach lengths of up to 1400 mm and widths of up to 400 mm. Currently, precision metal masks are produced through chemical etching, but this process has a low yield, necessitating subsequent laser processing for secondary processing and repair.

[0004] The difficulty in laser processing precision metal masks lies in the following: processing a 20μm 3D hole with a precision of less than 1μm and a 1° slope. Therefore, traditional laser processing methods are far from meeting these requirements for laser processing of precision metal masks. A new processing head is needed to meet the requirements of small-scale, high-precision 3D processing.

[0005] Summary of the Invention

[0006] The technical problem to be solved by the present invention is: in order to solve the problems existing in the prior art in the above-mentioned background technology, a fine metal mask laser processing device and a processing method thereof are provided, which have the three-dimensional processing capability of a galvanometer processing head and a dynamic focusing lens, the plane shaping capability of a field lens, and the ultra-fine observation and processing capability of an objective lens.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a fine metal mask laser processing device, comprising

[0008] The galvanometer processing head is used to deflect the incident laser beam throughout the entire galvanometer travel, ultimately changing the spatial position of the laser focus spot in the XY direction in real time;

[0009] Dynamic focusing module: a galvanometer processing head is installed on one side of the dynamic focusing module, and a laser head is installed on the other side. It is used to change the incident laser divergence angle in real time and inject a laser beam with a certain laser divergence angle into the galvanometer processing head, thereby changing the spatial position of the final laser focus spot in the Z direction;

[0010] The laser shaping module is located below the galvanometer processing head and is used to fully deflect the galvanometer to ensure processing accuracy, focus the laser to the focal plane inside the laser shaping module, and finally maintain the flat focal plane at the focal length of the objective lens;

[0011] The objective lens switching module is located below the laser shaping module and is equipped with several objective lenses of different magnifications.

[0012] The third beam combiner is located between the laser shaping module and the objective lens switching module;

[0013] The autofocus module is located on one side of the third beam combiner. The autofocus module emits a measuring laser beam, combines it with the laser beam through the third beam combiner, and finally focuses it on the surface of the object through the objective lens.

[0014] Furthermore, the laser shaping module includes a field mirror-like telecentric focusing mirror, a plano-convex shaping mirror, and a lumen. The light input end of the lumen is equipped with a field mirror-like telecentric focusing mirror, and the light output end of the lumen is equipped with a plano-convex shaping mirror. The convex surface of the plano-convex shaping mirror faces the inner cavity of the lumen, and the flat surface of the plano-convex shaping mirror is arranged outward.

[0015] Furthermore, the focal length ratio between the field mirror-like telecentric focusing lens and the plano-convex shaping lens is 1:2-20.

[0016] Furthermore, the objective lens switching module is a linear objective lens switching module, which includes a linear motor and a grating ruler. The linear motor is connected to the grating ruler through a transmission assembly and drives the grating ruler to perform linear reciprocating motion along the X-axis direction.

[0017] Furthermore, a plurality of lens groups are provided inside the field mirror-like telecentric focusing lens for focusing the laser light emitted from the galvanometer processing head into a focusing plane at the upper part of the lumen.

[0018] Furthermore, a first beam combiner and a second beam combiner are installed in sequence from top to bottom between the laser shaping module and the third beam combiner. A coaxial observation module for coaxial observation is provided on one side of the first beam combiner, and a coaxial lighting module for illumination is provided on one side of the second beam combiner.

[0019] Furthermore, the tilt direction of the first beam combiner is consistent with the tilt direction of the second beam combiner, and the tilt direction of the first beam combiner is opposite to the tilt direction of the third beam combiner.

[0020] A processing method of a fine metal mask laser processing device includes the fine metal mask laser processing device, specifically the following steps:

[0021] Step 1: Focus Calibration

[0022] Step 11: Calibrate the autofocus module to make it focus;

[0023] Step 12: When the autofocus module is focused, adjust the focal length of the coaxial observation module to ensure that the coaxial observation focus is in focus with the autofocus focus;

[0024] Step 13: When the automatic focusing module is focused, adjust the dynamic focusing module to ensure that the focus of the processing laser beam is aligned with the focus of the automatic focusing module and the focus of the coaxial observation module, thus completing the calibration of the processing head.

[0025] Step 2: Product processing

[0026] Step 21: The processing laser is controlled by the galvanometer processing head and the dynamic focusing module, and finally the laser is swung by the three-dimensional spatial position of the focus after the objective lens is focused.

[0027] Perform three-dimensional processing;

[0028] Step 22: Use software to draw a three-dimensional processing graphic, generate a processing trajectory, and perform plane or surface layer filling processing on the three-dimensional processing graphic, that is, perform rough processing on the three-dimensional hole;

[0029] Step 23: Setting a 3D contour scanning program for the above 3D graphics, and performing laser flattening on the 3D hole wall after 3D processing, that is, performing fine processing on the 3D hole wall;

[0030] Step 24: Setting a top surface cleaning program after the three-dimensional graphics processing, and performing laser cleaning on the dust or slag on the top surface of the mask after the three-dimensional processing.

[0031] Furthermore, during the product processing in step 2, real-time visual inspection is performed through the coaxial observation module, and the height of the galvanometer processing head in the Z-axis direction can also be adjusted in real time through the automatic focusing module.

[0032] The beneficial effects of the present invention are as follows: 1. The laser shaping module of the present invention includes a field lens-like telecentric focusing lens and a plano-convex shaping lens. Since the laser shaping module is ultimately processed by an objective lens, the processing range of the objective lens is very small, generally within the range of 0.1 mm. Therefore, it is difficult to use the full galvanometer stroke by deflecting the galvanometer, and thus it is difficult to ensure processing accuracy. By adding a field lens-like telecentric focusing lens, it is possible to ensure that the galvanometer processing head deflects within the full stroke (the field lens can ensure that the laser is focused within a certain small range within the full stroke of the galvanometer), and the focal length ratio of the field lens-like telecentric focusing lens and the plano-convex shaping lens is designed to be about 1:2 to 20, ensuring that the laser becomes parallel light after passing through the plano-convex shaping lens (the dynamic focusing module will slightly change the divergence angle, which is negligible here), and the spot diameter is expanded to 2 to 20 times the original (the larger the spot diameter, the smaller the focused spot, and the finer the processing scale);

[0033] 2. The device proposed in the present invention integrates a galvanometer processing head, a dynamic focusing lens, a field lens-like telecentric focusing lens, a plano-convex shaping lens, and an objective lens into one, while having the three-dimensional processing capabilities of the galvanometer processing head and the dynamic focusing lens, the planar shaping capabilities of the field lens, and the ultra-fine observation and processing capabilities of the objective lens; the above hardware is not a simple stacked combination, but through principle innovation, the processing capabilities of multi-scale laser processing components are combined, thereby realizing a new processing device and processing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and examples.

[0035] FIG1 is a schematic structural diagram of the present invention;

[0036] Figure 2 is a schematic diagram of the optical path of the laser shaping module;

[0037] In the figure: 1. Galvanometer processing head, 2. Dynamic focusing module, 3. Laser shaping module, 4. Automatic focusing module, 5. Coaxial observation module, 6. Coaxial lighting module, 7. Objective lens, 8. Objective lens switching module,

[0038] 9. First beam combiner, 10. Second beam combiner, 11. Third beam combiner,

[0039] 12. Field lens-like telecentric focusing lens, 13. Plano-convex shaping lens, 14. Lumen;

[0040] 15.Focusing plane, 16.Parallel light. DETAILED DESCRIPTION

[0041] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0042] As shown in Figures 1 and 2, a fine metal mask laser processing device processes micro-scale special-shaped holes (that is, three-dimensional holes). The laser is shot from top to bottom, and the laser can swing through the galvanometer, and can swing in three dimensions (left and right, front and back, up and down);

[0043] The principle of 3D processing: the large-scale laser is reduced by the tube diameter. This is because the original galvanometer has a large format, which is several hundred millimeters. Then the scene-like telecentric focusing mirror 12 is used to reduce the format of the scene of several hundred millimeters to a few microns, which is reduced by thousands of times. Then, the ratio of 1:4 is used to amplify the laser twice. This is due to the characteristics of the laser: the incident spot should be large and the focused spot should be small. This is to make the parallel light very coarse so that the focus can be very small, so that the processing quality is higher.

[0044] The galvanometer processing head 1 is composed of two sets of motors.16 or 2 20 The swing amplitude is 2 16 or 2 20 The swing amplitude is the full stroke, and the incident laser beam is deflected by the full galvanometer stroke, and finally the spatial position of the laser focus spot in the XY direction is changed in real time, so that the swing angle uses the full stroke of the small format, which is achieved through a focusing and amplification method;

[0045] Dynamic focusing module 2: A galvanometer processing head 1 is installed on one side of the dynamic focusing module 2, and a laser head is installed on the other side. The dynamic focusing module 2 is used to change the divergence angle of the incident laser in real time and inject a laser beam with a certain laser divergence angle into the galvanometer processing head 1, thereby changing the spatial position of the final laser focus spot in the Z direction. The galvanometer processing head 1 and the dynamic focusing module 2 can control the position of the final laser focus spot in three-dimensional space with high speed and high precision;

[0046] The laser shaping module 3 is located below the galvanometer processing head 1 and is used to fully deflect the galvanometer to ensure processing accuracy, and to focus the laser on the focal plane 15 inside the laser shaping module 3, and finally maintain the characteristics of the flat focal plane at the focal length of the objective lens;

[0047] The objective lens switching module 8 is located below the laser shaping module 3 and is equipped with a number of objective lenses 7 of different magnifications;

[0048] The third beam combiner 11 is located between the laser shaping module 3 and the objective lens switching module 8;

[0049] The automatic focusing module 4 is located on one side of the third beam combiner 11. The measuring laser is emitted from the automatic focusing module 4, and is combined with the laser beam through the third beam combiner 11, and finally focused on the surface of the object through the objective lens 7. After reflection, the measuring laser is imaged inside the automatic focusing module 4, and the focal position of the objective lens is determined by the imaging principle.

[0050] Specifically, the automatic focusing module 4 emits a measuring laser from inside to achieve automatic focusing, which is similar to a laser microscope. It automatically focuses based on the principle of laser. That is to say, the automatic focusing module 4 will emit a laser and reflect a laser, and the principle of confocalization can achieve automatic search for a focus.

[0051] The autofocus module 4 needs to be placed at the bottom because it needs to be very precise. If the autofocus module 4 is placed above, it will pass through three beam-combining mirrors, and the focusing performance of the autofocus module 4 will deteriorate. Therefore, the autofocus module 4 is placed closest to the objective lens 7.

[0052] The autofocus module 4 acts as a laser source for emitting laser light. The laser light in the 750-wavelength band hits the third beam combiner 11, and then reflects downward to the objective lens 7. It is then focused by the objective lens 7 and then reflected back again. The reflected image is used to determine whether the focal length of the objective lens 7 is correct, the quality of the image and the angle of the divergent laser, thereby determining whether the laser hits the front surface of the product.

[0053] The laser shaping module 3 flattens the light coming out of the galvanometer. The purpose of flattening is to make the focal plane of the laser on a plane. The focal plane is an arc-shaped focal plane. The laser shaping module 3 includes a field mirror-like telecentric focusing mirror 12, a plano-convex shaping mirror 13, and a lumen 14. The light input end of the lumen 14 is equipped with a field mirror-like telecentric focusing mirror 12, and the light output end of the lumen 14 is equipped with a plano-convex shaping mirror 13. The convex surface of the plano-convex shaping mirror 13 faces the inner cavity of the lumen 14, and the flat surface of the plano-convex shaping mirror 13 is set outward.

[0054] Among them, the field mirror telecentric focusing mirror 12 is internally provided with a plurality of groups of mirrors for focusing the laser light emitted from the galvanometer processing head 1 on the focusing plane 15 at the upper part of the lumen 14. The field mirror telecentric focusing mirror 12 will focus the laser light into the same plane, i.e., the focusing plane 15. That is to say, the general focal plane is a spherical surface, while the field mirror telecentric focusing mirror 12 in the present invention will convert the conventional spherical surface into a plane, thereby ensuring that the focal plane of the laser light finally emitted from the objective lens 7 is also a plane, rather than a traditional spherical surface, thereby ensuring the three-dimensional spatial accuracy of the laser focus. If the laser light is not flat, the focus entering the objective lens 7 is also not flat, and the focus is inconsistent, so it cannot be used. Therefore, the focusing plane 15 must be a plane, that is, the arc-shaped focal plane is converted into a parallel focal plane. Preferably, the focal length ratio between the field mirror-like telecentric focusing lens 12 and the plano-convex shaping lens 13 is 1:4. After passing through the focusing plane 15 in the lumen 14, the laser further becomes a divergent laser and enters the plano-convex shaping lens 13. The plano-convex shaping lens 13 shapes the divergent laser into parallel light 16 and expands the original incident light spot diameter by about 4 times.

[0055] At the same time, it is also to make the scale of the emitted parallel light controllable. If the scale is reduced, the emitted parallel light will become thinner. If it becomes thinner, the focused light spot will be large, and the quality will be poor.

[0056] Then, according to the quasi-plano-convex shaping mirror 13, the purpose of the quasi-plano-convex shaping mirror 13 is to convert the divergent light (the divergent light is conical) into parallel light 16 after it comes out of the cone. At this time, since the focal plane has been flattened before, the focal plane is still flat.

[0057] As shown in FIG1 , the objective lens switching module 8 is a linear objective lens switching module, which includes a linear motor and a grating ruler. The linear motor is connected to the grating ruler through a transmission assembly and drives the grating ruler to perform linear reciprocating motion along the X-axis direction.

[0058] Specifically, the objective lens switching module 8 is driven by a linear motor, and a high-precision grating ruler provides real-time feedback on the position of the objective lens 7, and switches objective lenses 7 of different magnifications at high speed and high precision through the linear switching principle.

[0059] The existing ones generally use an annular objective lens switching module, but the annular objective lens switching module is not as accurate as the linear objective lens switching module. This is because the annular one does not have a grating ruler, while the linear objective lens switching module is made with a grating ruler, which has an accuracy of 0.1um, achieving high-speed and high-precision switching.

[0060] Among them, the objective lens 7 is a parfocal objective lens, that is, the four objective lenses 7 are just different in magnification, but their focal lengths are the same, that is, the focal planes of the four objective lenses 7 are the same plane;

[0061] The focal plane of the objective lens 7 is very short, only 1 micron, which means that it cannot be focused if the height difference of 1 μm is reached.

[0062] A first beam combiner 9 and a second beam combiner 10 are installed in sequence from top to bottom between the laser shaping module 3 and the third beam combiner 11. A coaxial observation module 5 for coaxial observation is provided on one side of the first beam combiner 9, and a coaxial lighting module 6 for lighting is provided on one side of the second beam combiner 10.

[0063] The coaxial observation module 5 and the coaxial lighting module 6 are coaxial with the laser through the first beam combiner 9 and the second beam combiner 10 respectively, and play the role of illumination and coaxial observation; the coaxial observation module 5 includes a zoomable industrial camera.

[0064] The tilt direction of the first beam combiner 9 is consistent with the tilt direction of the second beam combiner 10 , and the tilt direction of the first beam combiner 9 is opposite to the tilt direction of the third beam combiner 11 .

[0065] Among them, the galvanometer processing head 1, dynamic focusing module 2, first beam combining mirror 9, second beam combining mirror 10, third beam combining mirror 11, coaxial observation module 5, coaxial lighting module 6 and objective lens 7 are all existing technologies and can be purchased from the market according to the requirements of the processing device.

[0066] A processing method of a fine metal mask laser processing device includes the fine metal mask laser processing device, specifically the following steps:

[0067] Step 1: Focus Calibration

[0068] Step 11: Calibrate the autofocus module 4 so that it focuses on the focal plane. The focal point is very accurate, and the focal plane of the dynamic focus module 2 is consistent with the focal plane.

[0069] Step 12: When the autofocus module 4 is focused, adjust the focal length of the coaxial observation module 5 to ensure that the coaxial observation focus is in focus with the autofocus focus;

[0070] Step 13: When the automatic focusing module 4 is focused, adjust the dynamic focusing module 2 to ensure that the focus of the processing laser beam is aligned with the focus of the automatic focusing module 4 and the focus of the coaxial observation module 5, thereby completing the calibration of the processing head.

[0071] Step 2: Product processing

[0072] Step 21: The processing laser is controlled by the galvanometer processing head 1 and the dynamic focusing module 2, and the three-dimensional spatial position of the focus after the objective lens 7 is finally focused is used to swing the laser to perform three-dimensional processing. During the product processing, real-time visual inspection is performed through the coaxial observation module 5, and the height of the galvanometer processing head 1 in the Z-axis direction can also be adjusted in real time by the automatic focusing module 4.

[0073] Step 22: Use software to draw a three-dimensional processing graphic, generate a processing trajectory, and perform plane or surface layer filling processing on the three-dimensional processing graphic, that is, perform rough processing on the three-dimensional hole;

[0074] Step 23: Setting a 3D contour scanning program for the above 3D graphics, and performing laser flattening on the 3D hole wall after 3D processing, that is, performing fine processing on the 3D hole wall;

[0075] Step 24: Setting a top surface cleaning program after the three-dimensional graphics processing, and performing laser cleaning on the dust or slag on the top surface of the mask after the three-dimensional processing.

[0076] Furthermore, during step 2 of the product processing, real-time visual inspection is performed via the coaxial observation module 5, and the Z-axis height of the galvanometer processing head 1 can be adjusted in real time via the autofocus module 4. The processing is automated and completed in one go by the galvanometer processing head and the dynamic focusing module, and the processing parameters for each step, including all processing motion parameters and laser parameters, can be independently set.

[0077] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A fine metal mask laser processing device, characterized in that: include The galvanometer processing head (1) is used to deflect the incident laser beam over the entire galvanometer travel, and finally change the spatial position of the laser focus spot in the XY direction in real time; A dynamic focusing module (2), wherein a galvanometer processing head (1) is installed on one side of the dynamic focusing module (2), and a laser head is installed on the other side thereof, and is used to change the divergence angle of the incident laser in real time, and to inject a laser beam with a certain laser divergence angle into the galvanometer processing head (1), thereby changing the spatial position of the final laser focusing spot in the Z direction; The laser shaping module (3) is located below the galvanometer processing head (1) and is used to fully swing the galvanometer to ensure processing accuracy, and to focus the laser on the focusing plane (15) inside the laser shaping module (3), and finally to maintain the plane focal plane at the focal length of the objective lens (7); An objective lens switching module (8) is located below the laser shaping module (3), and a plurality of objective lenses (7) with different magnifications are mounted on the objective lens switching module (8); A third beam combining mirror (11) is located between the laser shaping module (3) and the objective lens switching module (8); The automatic focusing module (4) is located on one side of the third beam combining mirror (11). The automatic focusing module (4) emits a measuring laser beam inside, combines the beam with the laser beam through the third beam combining mirror (11), and finally focuses on the surface of the object through the objective lens (7).

2. The fine metal mask laser processing device according to claim 1, characterized in that: The laser shaping module (3) comprises a field lens-like telecentric focusing lens (12), a plano-convex shaping lens (13), and a tube cavity (14); the field lens-like telecentric focusing lens (12) is installed at the light input end of the tube cavity (14); the plano-convex shaping lens (13) is installed at the light output end of the tube cavity (14); the convex surface of the plano-convex shaping lens (13) faces the inner cavity of the tube cavity (14), and the plane of the plano-convex shaping lens (13) faces outward.

3. The fine metal mask laser processing device according to claim 2, characterized in that: The focal length ratio between the field mirror-like telecentric focusing mirror (12) and the plano-convex shaping mirror (13) is 1:2-20.

4. The fine metal mask laser processing device according to claim 2, characterized in that: The field mirror-like telecentric focusing mirror (12) is internally provided with a plurality of mirror groups for focusing the laser light emitted by the galvanometer processing head (1) into a focusing plane at the upper part of the tube cavity (14).

5. The fine metal mask laser processing device according to claim 1, characterized in that: The objective lens switching module (8) is a linear objective lens switching module, and the objective lens switching module (8) comprises a linear motor and a grating ruler, wherein the linear motor is connected to the grating ruler via a transmission component, and drives the grating ruler to perform linear reciprocating motion along the X-axis direction.

6. The fine metal mask laser processing device according to claim 1, characterized in that: A first beam combining mirror (9) and a second beam combining mirror (10) are installed in sequence from top to bottom between the laser shaping module (3) and the third beam combining mirror (11); a coaxial observation module (5) for realizing coaxial observation is provided on one side of the first beam combining mirror (9); and a coaxial lighting module (6) for realizing lighting is provided on one side of the second beam combining mirror (10).

7. A processing method of a fine metal mask laser processing device, comprising the fine metal mask laser processing device according to any one of claims 1 to 6, characterized in that: The specific steps are as follows: Step 1: Focus Calibration Step 11: calibrating the automatic focusing module (4) so ​​that the automatic focusing module (4) is focused; Step 12: When the automatic focusing module (4) is in focus, the focal length of the coaxial observation module (5) is adjusted to ensure that the coaxial observation focus is in focus with the automatic focusing focus; Step 13: When the automatic focusing module (4) is in focus, the dynamic focusing module (2) is adjusted to ensure that the focus of the processing laser beam is aligned with the focus of the automatic focusing module (4) and the coaxial observation module (5). The three focal points are in focus, completing the calibration of the processing head; Step 2: Product processing Step 21: Control the processing laser through the galvanometer processing head (1) and the dynamic focusing module (2), and finally swing the laser through the three-dimensional spatial position of the focus after being focused by the objective lens (7) to perform three-dimensional processing; Step 22: Draw a three-dimensional processing graphic through software, generate a processing trajectory, and perform plane or surface layered filling processing on the three-dimensional processing graphic, that is, perform rough processing on the three-dimensional hole; Step 23: Setting a 3D contour scanning program of the above 3D graphics, and performing laser flattening on the 3D hole wall after 3D processing, that is, performing fine processing on the 3D hole wall; Step 24: Setting a cleaning procedure for the upper surface after the three-dimensional graphics processing, and performing laser cleaning on the dust or slag on the upper surface of the mask after the three-dimensional processing.

8. The method for processing a fine metal mask laser processing device according to claim 7, characterized in that: During the product processing of step 2, real-time visual inspection is performed through the coaxial observation module (5), and the height of the galvanometer processing head (1) in the Z-axis direction can also be adjusted in real time through the automatic focusing module (4).

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