A laser processing method for a multilayer film cross-sectional structure or a multilayer composite substrate

Abstract

A laser processing method for a multilayer film cross-section structure or a multilayer composite material substrate, comprising the following steps: (1) determining the range to be processed of the multilayer film cross-section structure or the multilayer composite material substrate; (2) determining the intensity of the laser beam emitted by the high-precision positioning current scanner, the scanning length L of the laser beam and the moving distance D of the laser beam along the line to be processed per second; (3) scanning the laser emitted by the high-precision positioning current scanner along the line to be processed with a length of L, and moving the laser emitted by the current scanner along the line to be processed with a moving distance of D per second, and only when the position corresponding to the laser beam is in the position to be processed, the laser is emitted, and when the position corresponding to the laser beam is outside the position to be processed, the laser is turned off; (4) scanning and moving along the line to be processed by the laser beam emitted by the current scanner. Through the linkage of the electrically controlled three-dimensional displacement table and the workbench, the problem of large-area material processing is solved.

Description

Technical Field

[0001] This invention belongs to the field of laser processing, and specifically relates to a laser processing method for multilayer film cross-sectional structures or multilayer composite material substrates. Background Technology

[0002] With the development of ultra-high density and ultra-micro manufacturing technology, consumers are increasingly favoring thinner, lighter, and simpler electronic products. Therefore, product development and improvement not only involve enhancing basic performance but also demanding thinner, lighter, and more robust designs.

[0003] Currently, flexible screens are the mainstream type in the mobile phone display market, and foldable screens are expected to follow suit in the future. Both types of display panels are composed of multiple layers of composite films, and precise cutting and processing are required to manufacture them into desired shapes.

[0004] However, traditional laser cutting processes cannot avoid material deformation or damage caused by heat. To minimize this heat effect, lasers with very short pulses can be used for cutting, but improving quality solely by increasing the laser pulse amplitude is limited. Summary of the Invention

[0005] The purpose of this invention is to provide a laser processing method for multilayer film cross-section structures or multilayer composite material substrates that can overcome the defects of material deformation or damage caused by heat effects, and has high processing accuracy and fast processing speed.

[0006] The technical solution of this invention is: a laser processing method for multilayer film cross-sectional structures or multilayer composite material substrates, characterized by comprising the following steps: (1) Determine the processing range of the multilayer membrane cross-section structure or multilayer composite material substrate; (2) Determine the intensity of the laser beam emitted by the high-precision positioning current scanner, the scanning length L of the laser beam, and the distance D per second that the laser beam moves along the line to be processed, based on the material of the substrate to be processed. The scanning length L is an integer multiple of the distance D per second and 15D≥L≥6D. (3) The laser emitted by the high-precision positioning current scanner scans along the line to be processed for a length of L. At the same time, the laser emitted by the current scanner moves along the line to be processed at a distance of D per second. The laser is emitted only when the position corresponding to the laser beam is at the position to be processed. When the position corresponding to the laser beam is outside the position to be processed, the laser is turned off.

[0007] (4) The laser beam emitted by the overcurrent scanner moves along the line to be processed until the processing is completed.

[0008] Preferably, the laser beam enters the high-precision positioning current scanner responsible for position control through the optical path device, and then passes through the telecentric F-theta field lens to process the substrate to be processed. The current scanner is moved in position by an electrically controlled three-dimensional displacement stage.

[0009] Preferably, the high-precision positioning current scanner can move along the XY axis while scanning with a laser, and the substrate to be processed is fixed on a worktable that can move along the XY axis.

[0010] Preferably, when the area to be processed on the substrate is smaller than the working area of ​​the field lens laser beam, the worktable does not move, and the processing of the substrate is completed only by moving the high-precision positioning current scanner.

[0011] Preferably, when the area to be processed on the substrate is larger than the working area of ​​the field lens laser beam, the processing of the substrate is completed by moving the worktable, while the high-precision positioning current scanner is finely adjusted to compensate for the movement of the worktable.

[0012] Preferably, the multilayer film cross-section structure or multilayer composite material substrate is a flexible OLED display panel with a resin structure having a composite film and a foldable display panel with a similar structure.

[0013] The advantages of this invention are: 1. During processing, the adhesive layer in the middle of the polyimide substrate will not melt due to the heat of processing, the cut layers are clearly distinguishable, and the cut surface is smooth and neat; 2. Improved processing speed. Processing quality is related to processing speed; the slower the speed, the worse the processing quality. This is because a slower speed results in a higher overlap rate of laser processing pulses, a higher processing energy density of the material, and a greater degree of thermalization. If the material is heat-sensitive, then processing speed becomes the main variable determining processing quality. Traditional processing can only maintain a certain speed; processing cannot be completed at higher speeds. The improved processing method of this invention can improve speed. It is about 10 times faster than the maximum speed of general processing, especially for processing heat-sensitive materials, achieving high quality while being about 10 times faster than the maximum speed of general processing.

[0014] 3. By employing an XY-axis moving worktable and a high-precision positioning current scanner with fine-tuning compensation, the machining accuracy of the product can be improved. While a worktable has a large movement range and high speed, its accuracy is low. A current scanner, on the other hand, has a small movement range and slow speed but high accuracy. This invention utilizes high-speed linkage control technology for the scanner to perform high-speed, precision machining of large-area materials. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 These are diagrams of the cross-sectional structures of multilayer membranes and multilayer composite materials.

[0016] Figure 2 This is a schematic diagram of the processing method of the present invention.

[0017] Figure 3 This is a comparison diagram between existing processing methods and the processing method of the present invention.

[0018] Figure 4 A comparison is made between the cutting results of multilayer films using existing processing methods and the processing method of the present invention.

[0019] Figure 5 The results show the comparison of laser-cut cross-sections of multilayer films.

[0020] Figure 6 This is a comparison of the selective removal results of multilayer composite materials.

[0021] Figure 7 Comparison of selective removal results for multilayer composite materials. Implementation Example

[0022] like Figure 1 As shown, in this embodiment, the multilayer film cross-section structure substrate is a foldable image sensor panel, employing a three-layer PI structure with PI thicknesses of 20μm, 75μm, and 75μm, respectively, and a 10μm adhesive layer between the PI layers. The multilayer composite material substrate is a display panel, comprising a 2-6μm SiOx layer, a 20μm PI layer, and a 500μm glass layer, with a 10μm adhesive layer between each layer. The following embodiments all use these two materials. Figure 1 Mechanical cutting of multilayer films or composite materials is difficult, and laser cutting is currently the most common method. To minimize thermalization or deformation during processing, the following method is used: The laser beam enters a high-precision positioning current scanner (XY Galvao scanner) responsible for position control through an optical path device, and then passes through a telecentric F-theta field lens to focus the beam on the workpiece. Before processing, the high-precision positioning current scanner is moved to the position of the workpiece. If the workpiece is within the field lens area, the current scanner is moved for processing; if it is a large area of ​​workpiece exceeding the field lens area, the stage is moved for processing, and the current scanner simultaneously receives the coordinate position of the stage to compensate for the stage movement. Figure 2As shown, the intensity of the laser beam emitted by the high-precision positioning current scanner, the scan length L of the laser beam, and the distance D per second that the laser beam moves along the processing line are determined according to the material of the substrate to be processed. In this embodiment, L = 10D. The laser emitted by the high-precision positioning current scanner scans along the processing line for a length of L, while simultaneously moving along the processing line at a distance D per second. The laser is emitted only when the position corresponding to the laser beam is at the position to be processed; when the position corresponding to the laser beam is outside the position to be processed, the laser is turned off. The laser beam emitted by the current scanner scans and moves along the processing line until processing is completed. Figure 3 This diagram compares the traditional processing method with the improved processing method of this invention. The left side represents the prior art, and the right side represents the improved technology of this invention. Generally, MOF (Marking On the Fly) processing using an electrically controlled 3D stage and a Galvano current scanner is employed. If the process moves outside the scanner's processing area, the processing speed depends on the movement speed of the electrically controlled 3D stage. However, the relatively low movement speed of the electrically controlled 3D stage limits the processing speed, making high-speed processing difficult. Processing quality is related to processing speed; slower speeds result in poorer quality. This is because slower speeds lead to greater overlap of laser processing pulses, higher processing energy density of the material, and greater thermalization. If the material is heat-sensitive, the movement speed becomes the primary variable affecting processing quality. Figure 3 The left image shows a different common processing method, while the right image shows an improved method. This improved method addresses the issue of thermal deformation through high-speed repetitive laser scanning and overcomes the slow movement speed of the electrically controlled 3D displacement stage by moving the worktable. The stage compensates for the worktable's movement with fine adjustments, improving processing accuracy. While the worktable moves quickly, its accuracy is low; conversely, the stage, though slower, offers high precision. This improved method enhances both processing quality and speed, achieving optimal quality and approximately 10 times faster processing speeds for heat-sensitive materials. When processing small-area products, worktable movement is unnecessary; only the electrically controlled stage needs to be moved. By adjusting the laser scanning frequency and intensity, excellent processing results can be achieved.

[0023] Figure 4The images show magnified photographs of the cross-section of the multilayer film after laser processing, taken under an optical microscope. The material to be processed consists of a multilayer structure composed of three layers of polyimide (PI) film and an interlayer adhesive layer. Taking a conventional processing method as an example, the heat-affected zone (HAZ) of the laser-cut section is within 30 μm, while with the improved processing method, the HAZ is within 15 μm, reducing the thermalization of the material by more than 50%. Figure 5 and Figure 4 As shown, taking the cutting of multilayer films as an example, the quality of the cut cross-section is magnified and compared under an optical microscope, and the results are as follows. Figure 5 As shown, the HAZ (heat-affected zone) of conventional processing methods is less than 25 μm, while the HAZ is less than 10 μm after using the method of this invention. With conventional processing, the adhesive layer in the middle of the polyimide melts due to the processing heat, causing the cut surface to bend. However, with the improved processing method of this invention, the adhesive layer does not melt, the cut layers are clearly distinguished, and the cut surface is smooth and neat. Figure 6 Multilayer composite material ( Figure 1 In the example of laser cutting of materials in the present invention, when the improved processing method is used for the upper SiOx layer, the heat-affected zone is reduced by more than 50% compared with the conventional method. The HAZ of the conventional processing method is less than 30μm, while the HAZ of the improved processing method of the present invention is less than 15μm. Figure 7 This study compares the cross-sections of multilayer composite materials after laser cutting of some of the uncut portions, followed by further cutting using physical force, under an optical microscope. The comparison reveals that the improved processing method produces a more uniform and smoother cut surface with higher quality.

[0024] Besides the materials described in this embodiment, this invention can also be used to process multilayer materials with thermal reactivity, such as polyamide and polyethylene terephthalate. This invention solves the problem of large-area material processing by linking an electrically controlled three-dimensional displacement stage and a worktable. It can be effectively applied to the processing of thermally sensitive films, semiconductor composite materials, and cutting-edge materials for displays.

[0025] Of course, the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All modifications made according to the spirit and essence of the main technical solution of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A laser processing method for substrates used in multilayer membrane cross-section structures or multilayer composite materials, characterized in that, The process includes the following steps: (1) determining the processing range of the substrate of the multilayer membrane cross-section structure or multilayer composite material; (2) determining the intensity of the laser beam emitted by the high-precision positioning current scanner, the scanning length L of the laser beam, and the distance D per second that the laser beam moves along the processing line according to the material of the substrate to be processed, wherein the scanning length L is an integer multiple of the distance D per second and 15D≥L≥6D; (3) scanning the laser emitted by the high-precision positioning current scanner along the processing line for a length of L, and simultaneously moving the laser emitted by the current scanner along the processing line for a distance D per second. The laser is emitted only when the position corresponding to the laser beam is at the processing position, and the laser is turned off when the position corresponding to the laser beam is outside the processing position; (4) scanning and moving the laser beam emitted by the current scanner along the processing line. The laser beam passes through an optical path device into a high-precision positioning current scanner responsible for position control, and then passes through a telecentric F-theta field lens to process the substrate. The current scanner is moved by an electrically controlled three-dimensional displacement stage. The high-precision positioning current scanner can move along the XY axis while scanning with the laser, fixing the substrate to be processed on a worktable that can move along the XY axis. When the area to be processed on the substrate is smaller than the working area of ​​the field lens laser beam, the worktable does not move, and the processing of the substrate is completed only by moving the high-precision positioning current scanner. When the area to be processed on the substrate is larger than the working area of ​​the field lens laser beam, the processing of the substrate is completed by moving the worktable, while the high-precision positioning current scanner is finely adjusted to compensate for the movement of the worktable.

2. The laser processing method for a substrate used in a multilayer membrane cross-section structure or a multilayer composite material according to claim 1, characterized in that, The substrate of the multilayer film cross-section structure or multilayer composite material is a flexible OLED display panel with a resin structure having a composite film.

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