A high-throughput transfer method for solid thin films

Abstract

This invention relates to the field of laser transfer technology, and more particularly to a high-throughput transfer method for solid-state thin films, comprising the following steps: A) preparing a transfer film and a acceptor substrate; the transfer film includes a flexible transparent substrate and a solid-state thin film adhered to the inner surface of the flexible transparent substrate; the thickness of the solid-state thin film is 2–20 μm; B) applying a transfer laser to the transfer film, allowing the transfer laser to pass through the flexible transparent substrate and irradiate the solid-state thin film, causing the solid-state thin film to melt, transfer, and deposit onto the acceptor substrate. The high-throughput transfer method for solid-state thin films proposed in this invention is advantageous in ensuring high-throughput transfer and achieving high-efficiency forming while not only improving transfer stability but also reducing application costs, thus overcoming the shortcomings of existing technologies.

Description

Technical Field

[0001] This invention relates to the field of laser transfer technology, and more particularly to a high-throughput transfer method for solid films. Background Technology

[0002] Laser transfer printing is a microscale metal additive manufacturing technology based on the principle of laser-induced forward transfer (LIFT). It utilizes a laser to irradiate the donor material, driving the material to transfer and build the desired two-dimensional or three-dimensional structure through point-by-point deposition. Currently, the donor materials used in laser transfer printing are mainly divided into slurry systems and solid film systems. Slurries contain a large amount of organic binders, requiring debinding and sintering after transfer to form a solid structure. In contrast, using solid films as donors allows for direct fabrication of solid structures, resulting in a shorter process flow.

[0003] The thickness of solid films used in existing methods is generally in the nanometer or submicrometer range. For example, the US patent "LIFT printing of conductive traces onto asemiconductor substrate" (US2019088804A1) specifies a solid film thickness between 0.3 μm and 1.5 μm. This is because traditional laser transfer methods generally use a single short-pulse laser to irradiate the donor. The energy deposition time of such short-pulse lasers is extremely short, and the thermal diffusion effect is weak. When applied to a thicker solid film, the high peak power density of the short-pulse laser induces violent vaporization and plasma impact at the interface, causing the transfer process to change from controllable liquid-phase extrusion to disordered jetting, making stable transfer impossible. For these reasons, traditional laser transfer methods must use thin solid films.

[0004] Furthermore, because the solid films used in existing technologies are relatively thin, the peeling notch formed after the transfer laser irradiates the solid film is generally an inverted frustum structure that is wider at the top and narrower at the bottom. The volume of this inverted frustum structure determines the material throughput of a single transfer. In addition, since the height of the inverted frustum structure is positively correlated with the film thickness, the transfer throughput also increases with the increase of the solid film thickness. Therefore, traditional nanometer or submicron-scale solid films result in a small amount of material transferred per cycle, making it difficult to meet the requirements of high-efficiency molding.

[0005] To increase the amount of material transferred in a single pass, achieve high-throughput transfer, and meet the demands of high-efficiency molding, existing technologies have attempted to use thicker solid films in laser transfer processes. For example, Chinese invention patent CN119427983A discloses a high-throughput laser transfer method for thicker (≥5μm) solid films. Its core lies in achieving sufficient melting and effective transfer of the thicker solid film through a two-step laser irradiation strategy and specific power density and time interval design. However, the dual-laser transfer system constructed by this technology places extremely high demands on physical precision and timing control: the two laser beams must achieve strict spatial axis alignment to ensure the overlap of energy deposition areas; simultaneously, the pulse interval between the first and second transfer lasers needs to be controlled at nanosecond or even sub-nanosecond levels. This not only results in a very narrow process parameter window, where even small timing deviations can significantly reduce the transfer effect, such as incomplete melting, splashing, or substrate damage, affecting transfer stability, but also necessitates high-precision hardware timers for timing control, leading to high application costs. Summary of the Invention

[0006] The purpose of this invention is to propose a high-throughput transfer method for solid films, which not only improves transfer stability and reduces application costs while ensuring high-throughput transfer and high-efficiency molding, thus overcoming the shortcomings of the prior art.

[0007] To achieve this objective, the present invention adopts the following technical solution: A high-throughput transfer method for solid thin films includes the following steps: A. Prepare the transfer film and the receptor substrate; The transfer film includes a flexible transparent substrate and a solid film adhered to the inner surface of the flexible transparent substrate; The thickness of the solid film is 2 to 20 μm; the solid film includes a first metal film and a second metal film bonded together, the first metal film being in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film being ≤500 nm. B. Apply a transfer laser to the transfer film, allowing the transfer laser to pass through the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate; The pulse width of the transfer laser is 60–300 ns, and the wavelength is ≥500 nm.

[0008] Furthermore, in step B, the pulse width of the transfer laser is 120–300 ns.

[0009] Further, in step A, the solid film includes a first metal film and a second metal film bonded together, the first metal film being in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film being ≤500nm. The first metal film is deposited from a first metal; The second metal film is formed by depositing a second metal; When the first metal and the second metal are of the same type, and both the first metal and the second metal are crystalline structures, the average grain size of the first metal and the second metal are different. Alternatively, when the first metal and the second metal are of the same type, the first metal is amorphous and the second metal is crystalline.

[0010] Furthermore, the first metal is any one of copper, titanium, chromium, nickel, tin, copper alloy, titanium alloy, chromium alloy, nickel alloy, and tin alloy; The second metal is any one of copper, tin, silver, gold, copper alloy, tin alloy, silver alloy, and gold alloy; The peak energy flux density of the transfer laser when it reaches the solid film is 1–220 J / cm². 2 .

[0011] Further, in step A, the method for preparing the solid thin film is as follows: A first metal thin film is formed by depositing a first metal on the surface of a flexible transparent substrate; A second metal film is formed by electroplating or chemical plating a second metal on the surface of the first metal film, thus obtaining a solid film.

[0012] Furthermore, in step A, the thickness of the flexible transparent substrate is 5–200 μm.

[0013] The technical solution provided by this invention may include the following beneficial effects: 1. This technical solution, by limiting the pulse width of the transfer laser, not only achieves slow energy injection but also allows sufficient time for heat to conduct to the interior and periphery of the thicker solid film, rather than instantaneously vaporizing. This allows the thicker solid film to melt and form a stable molten pool with molten droplets. Simultaneously, the transfer laser with a wavelength ≥500nm avoids photodecomposition of the flexible transparent substrate, and the inner surface of the flexible transparent substrate undergoes minute and controllable thermal decomposition under continuous heat conduction, generating a gentle vapor pressure at the interface. Compared to the explosive impact caused by violent vaporization from short-pulse lasers used in traditional processes, this gentle vapor pressure guides the molten droplets to smoothly detach from the flexible transparent substrate with a lower initial velocity. This effectively avoids violent impacts and morphological distortions caused by excessive kinetic energy when the molten droplets contact the acceptor substrate, achieving controllable and stable transfer, thus ensuring transfer quality.

[0014] 2. Since the transfer throughput also increases with the increase of the solid film thickness, this technical solution uses a solid film with a thickness of 2 to 20 μm as the transfer object. Compared with the existing thin solid films at the nanometer and submicron level, the thickness of the solid film in this technical solution is significantly increased, which is conducive to increasing the throughput of a single transfer, improving the transfer efficiency, realizing high-throughput stable transfer, and meeting the requirements of high-efficiency molding.

[0015] 3. This technical solution requires only one transfer laser, eliminating the need for a first and second transfer laser. This not only simplifies the transfer process but also avoids the problem of decreasing transfer stability caused by the requirement to control the pulse interval between the first and second transfer lasers to the nanosecond or even sub-nanosecond level. This improves transfer stability. Furthermore, since this technical solution requires only one transfer laser and eliminates the need for a first and second transfer laser, it does not rely on high-precision hardware timers for timing control, thus reducing application costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a high-throughput laser transfer device for solid-state thin films according to the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the evolution of a solid thin film over time after being irradiated by a laser in Embodiment 1 of the present invention.

[0018] Figure 3 This is a schematic diagram illustrating the evolution of the highest temperature inside the solid film over time in Embodiment 1 of the present invention.

[0019] Figure 4 This is a schematic diagram showing the evolution of the solid film after irradiation over time in Comparative Example 1 of the present invention.

[0020] Figure 5This is a schematic diagram showing the evolution of the solid film over time after irradiation in Comparative Example 2 of the present invention.

[0021] Figure 6 This is a schematic diagram showing the evolution of the solid film in Comparative Example 3 of the present invention over time after irradiation.

[0022] Among them: 1. Feed roll, 2. Roller, 3. Tension detector, 4. Solid film, 5. Take-up roll, 6. Laser source, 7. Transfer laser, 8. Acceptor substrate, 9. Molten droplet. Detailed Implementation

[0023] This technical solution provides a high-throughput transfer method for solid thin films, including the following steps: A. Prepare the transfer film and the receptor substrate; The transfer film includes a flexible transparent substrate and a solid film adhered to the inner surface of the flexible transparent substrate; The thickness of the solid film is 2 to 20 μm; the solid film includes a first metal film and a second metal film bonded together, the first metal film being in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film being ≤500 nm. B. Apply a transfer laser to the transfer film, allowing the transfer laser to pass through the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate; The pulse width of the transfer laser is 60–300 ns, and the wavelength is ≥500 nm.

[0024] To address the technical challenges of simultaneously achieving high-throughput transfer, transfer stability, and application cost in existing technologies, this technical solution proposes a high-throughput transfer method for solid-state thin films. By improving the transfer method, it is beneficial to not only enhance transfer stability and reduce application costs while ensuring high-throughput transfer and efficient molding, thus meeting practical application needs.

[0025] First, this technical solution uses long-pulse-width lasers (60–300 ns) and transfer lasers with wavelengths ≥500 nm as heat sources, and solid films with thicknesses of 2–20 μm as the transfer target. Compared to ultrafast lasers with pulse widths in the femtosecond and picosecond range, longer pulse lasers in the millisecond, microsecond, and even nanosecond range have relatively slow energy release rates at the same peak energy flux density. This technical solution, by limiting the pulse width of the transfer laser, not only achieves slow energy injection but also allows sufficient time for heat to conduct to the interior and periphery of the thicker solid film, rather than instantaneously vaporizing, thereby melting the thicker solid film and forming a stable molten pool with molten droplets. Simultaneously, the transfer laser with a wavelength ≥500 nm avoids photo-induced decomposition of the flexible transparent substrate, and the inner surface of the flexible transparent substrate undergoes minute and controllable thermal decomposition under continuous heat conduction, generating a mild vapor pressure at the interface. Compared to the explosive impact caused by the violent vaporization generated by short-pulse lasers in traditional processes, the above-mentioned mild vapor pressure can guide the molten droplets to detach smoothly from the flexible transparent substrate with a lower initial velocity. This effectively avoids the violent impact and morphological distortion caused by excessive kinetic energy when the molten droplets come into contact with the acceptor substrate, achieving controllable and stable transfer, thus helping to ensure the quality of the transfer.

[0026] Meanwhile, this technical solution defines the first metal film in contact with the inner surface of the flexible transparent substrate as the seed layer. By limiting its thickness, it helps to solve the problem of stress caused by an excessively thick seed layer, which leads to a decrease in the bonding strength between the solid film and the flexible transparent substrate, resulting in the solid film being prone to detachment during the transfer and deposition process, thus improving the stability of the transfer.

[0027] Furthermore, since the transfer throughput also increases with the increase of the solid film thickness, this technical solution uses a solid film with a thickness of 2 to 20 μm as the transfer object. Compared with the existing thin solid films at the nanometer and submicron level, the thickness of the solid film in this technical solution is significantly increased, which is conducive to increasing the throughput of a single transfer, improving the transfer efficiency, realizing high-throughput stable transfer, and meeting the requirements of high-efficiency molding.

[0028] Secondly, this technical solution requires only one transfer laser, eliminating the need for a first and second transfer laser. This not only simplifies the transfer process but also avoids the problem of decreasing transfer stability caused by the requirement to control the pulse interval between the first and second transfer lasers to the nanosecond or even sub-nanosecond level, thus improving transfer stability. Furthermore, since this technical solution requires only one transfer laser and eliminates the need for a first and second transfer laser, it does not rely on high-precision hardware timers for timing control, which helps reduce application costs.

[0029] Furthermore, the transfer film in this technical solution uses a flexible transparent substrate, resulting in a highly flexible transfer film. During the transfer process, the transfer film can be transferred through a roll-to-roll system (specific device as follows). Figure 1 As shown, continuous material supply meets the needs of high-throughput laser transfer printing processes.

[0030] It should be noted that the flexible transparent substrate can be a polyethylene terephthalate film, and the specific type is not limited here.

[0031] Finally, it should be noted that transparent glass cannot be used as a substitute for the flexible transparent substrate in this technical solution for the following reasons: When transparent glass is used as the substrate for the solid film, the transfer laser energy passes through the transparent glass and acts directly on the interface between it and the solid film. Due to the high thermal stability of transparent glass, the interface will only soften and will not undergo thermal decomposition like the flexible transparent substrate. Therefore, during the transfer process, the system lacks the gentle gas pressure driving force to propel the molten droplets away.

[0032] To further explain, in step B, the pulse width of the transfer laser is 120–300 ns.

[0033] Under pulsed lasers with the same peak energy flux density, the shorter the pulse width, the faster the heat input rate. Therefore, when the pulse width of the transfer laser is too short, the temperature inside the solid film may rise sharply, exceeding the vaporization temperature in a short time, ultimately leading to explosive ejection and making it difficult to achieve stable overall transfer. If the pulse width is too long, the initial velocity of the molten droplets will be too low, making the droplets easily disturbed during flight, causing their flight trajectory to deviate. Furthermore, the density of the stacked molten layer decreases at excessively low velocities, reducing the quality of the three-dimensional structure transferred and deposited on the acceptor substrate.

[0034] To further explain, in step A, the solid film includes a first metal film and a second metal film that are bonded together. The first metal film is in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film is ≤500 nm. The first metal film is deposited from a first metal; The second metal film is formed by depositing a second metal; When the first metal and the second metal are of the same type, and both the first metal and the second metal are crystalline structures, the average grain size of the first metal and the second metal are different. Alternatively, when the first metal and the second metal are of the same type, the first metal is amorphous and the second metal is crystalline.

[0035] This technical solution defines the first metal and the second metal, thereby creating a difference between the first metal film and the second metal film. By using different metal films to block and disperse the residual stress inside the solid film, the interfacial bonding strength between the solid film and the flexible transparent substrate can be significantly improved, ensuring that the solid film can still adhere stably even when it reaches a thickness of micrometers.

[0036] Furthermore, when the first metal and the second metal are of the same type and both the first metal and the second metal are crystalline structures, the average grain size of the first metal and the second metal is different, which makes the first metal film and the second metal film form a grain size gradient. The mechanical interlocking effect generated by the above-mentioned grain size difference effectively buffers the interface stress and significantly enhances the bonding strength between the first metal film and the second metal film.

[0037] It should be noted that when the first metal and the second metal are of different types, the average grain size of the first metal and the second metal may be the same or different.

[0038] Preferably, when both the first metal and the second metal are crystalline structures, the average grain size of both the first metal and the second metal is 5 to 500 nm.

[0039] This technical solution, by limiting the average grain size of the first and second metals, is more conducive to blocking and dispersing residual stress inside the solid film, thereby improving the interfacial bonding strength between the solid film and the flexible transparent substrate.

[0040] To further clarify, the first metal is any one of copper, titanium, chromium, nickel, tin, copper alloy, titanium alloy, chromium alloy, nickel alloy, and tin alloy; The second metal is any one of copper, tin, silver, gold, copper alloy, tin alloy, silver alloy, and gold alloy; The peak energy flux density of the transfer laser when it reaches the solid film is 1–220 J / cm². 2 .

[0041] Copper, titanium, chromium, nickel, tin, copper alloys, titanium alloys, chromium alloys, nickel alloys, and tin alloys all exhibit good adhesion to flexible transparent substrates. Therefore, this technical solution limits the first metal to the aforementioned types, which not only allows for selection based on actual needs but also helps improve the bonding strength between the solid film and the flexible transparent substrate, preventing spontaneous cracking or large-area peeling of the solid film that could affect transfer stability.

[0042] Furthermore, the energy flux density of the transfer laser is affected by multiple factors such as the type of metal, pulse width, and thickness of the solid film. Therefore, this technical solution limits the range of energy flux density of the transfer laser under the premise of limiting the type of metal, pulse width, and thickness of the solid film, so that a suitable energy flux density can be selected according to actual needs, thereby helping to obtain better transfer stability.

[0043] To further explain, in step A, the method for preparing the solid thin film is as follows: A first metal thin film is formed by depositing a first metal on the surface of a flexible transparent substrate; A second metal film is formed by electroplating or chemical plating a second metal on the surface of the first metal film, thus obtaining a solid film.

[0044] Existing technologies use glass as a carrier for solid-state thin films. Preparing solid-state thin films on glass surfaces requires a vacuum deposition process, which has a slow deposition rate. Furthermore, when the film thickness reaches the micrometer scale, internal stress issues can easily arise, affecting film quality. In contrast, this technology uses a method of first depositing on a flexible transparent substrate followed by electroplating or chemical plating to prepare solid-state thin films. This method is highly efficient and low-cost. Moreover, when the solid-state film thickness reaches several micrometers, the internal stress is low, and there is no cracking or large-area peeling. The resulting solid-state film has high quality, thus improving the stability of the transfer process.

[0045] Furthermore, based on the solid film preparation method of this technical solution, the solid film in this technical solution has a high bonding strength with the flexible transparent substrate, avoiding the drawbacks of difficulty in ensuring the uniformity and stability of the bonding and easy increase of process uncertainty when the solid film is fixed to the flexible transparent substrate by adhesive.

[0046] To further explain, in step A, the thickness of the flexible transparent substrate is 5–200 μm.

[0047] To ensure the transfer film maintains both flexibility and sufficient strength, this technical solution limits the thickness of the flexible transparent substrate to 5–200 μm.

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0049] Example 1 A. Prepare the transfer film and the receptor substrate; The solid film is prepared as follows: copper is deposited on the surface of a polyethylene terephthalate film by vacuum evaporation to form a copper film with a thickness of 500 nm and an average grain size of 300 nm; copper is then chemically plated on the surface of the copper film with a thickness of 500 nm and an average grain size of 300 nm to form a copper film with a thickness of 1.5 μm and an average grain size of 50 nm, thus obtaining a solid film. B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 60 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 1.4 J / cm². 2 .

[0050] The layered structure of the transfer film, from top to bottom, is shown in the table below:

[0051] like Figure 2 As shown, when a transfer laser acts on a solid-state thin film, the laser energy is absorbed by the film and rapidly converted into heat energy during the pulse duration. This causes the copper in the localized solid-state film to heat up quickly and melt, forming a molten pool. The evolution of the highest temperature inside the copper film over time after the transfer laser begins to act on the solid-state film is as follows: Figure 3 As shown, the highest temperature inside the copper film is close to but does not exceed the vaporization temperature of metallic copper (2835K), indicating that large-scale vaporization did not occur in the solid film at this point, and heat conduction was the primary process. Under continuous heat conduction, the inner surface of the flexible transparent substrate undergoes a small and controllable thermal decomposition, generating a mild vapor pressure at the interface. This mild vapor pressure propels the molten droplets away from the donor film at a relatively low initial velocity. Due to the relatively long laser pulse width and ample energy deposition time, heat has sufficient time to conduct to the surrounding metal, resulting in a large molten pool and a large amount of molten metal.

[0052] In this embodiment, the calculated average single droplet volume is 635.25 µm. 3 With a laser frequency of 80kHz, its ideal transfer efficiency can reach 182.95mm. 3 / h can achieve a stable and high-throughput transfer effect.

[0053] Example 2 A. Prepare the transfer film and the receptor substrate; The solid film is prepared by depositing nickel on the surface of a polyethylene terephthalate film by magnetron sputtering to form an amorphous nickel film with a thickness of 20 nm; and electroplating copper on the surface of the amorphous nickel film with a thickness of 20 nm to form a copper film with a thickness of 6 μm and an average grain size of 400 nm, thus obtaining a solid film. B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 100 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 22.3 J / cm². 2 .

[0054] The layered structure of the transfer film, from top to bottom, is shown in the table below:

[0055] With the increase in the thickness of the solid film, the peak energy flux density must be increased accordingly to ensure sufficient energy for transfer, while keeping the spot size constant. To avoid violent metal vaporization and sputtering caused by the increased peak energy flux density, the pulse width needs to be increased simultaneously. A longer pulse time can make the energy input process smoother, ensuring that the maximum temperature of the solid film never exceeds the vaporization temperature of copper. This allows the flexible transparent substrate to undergo stable thermal decomposition under heat conduction, thereby maintaining a mild and controllable transfer mechanism.

[0056] In this embodiment, the calculated average single droplet volume is 2589.19 µm. 3 With a laser frequency of 80kHz, its ideal transfer efficiency can reach 745.69mm. 3 / h can achieve a stable and high-throughput transfer effect.

[0057] Example 3 A. Prepare the transfer film and the receptor substrate; The solid film is prepared as follows: titanium is deposited by magnetron sputtering on the surface of a polyethylene terephthalate film to form a titanium film with a thickness of 50 nm and an average grain size of 10 nm; copper is electroplated on the surface of the titanium film with a thickness of 500 nm and an average grain size of 10 nm to form a copper film with a thickness of 19.5 μm and an average grain size of 100 nm, thus obtaining a solid film; B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 300 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 210.3 J / cm². 2 .

[0058] The layered structure of the transfer film, from top to bottom, is shown in the table below:

[0059] The above embodiments, by synchronously increasing the pulse width and the longer pulse time, can make the energy input process smoother, and the maximum temperature of the solid film never exceeds the vaporization temperature of copper metal, so that the flexible transparent substrate can undergo thermal decomposition smoothly under heat conduction, thereby maintaining a mild and controllable transfer mechanism.

[0060] In this embodiment, the calculated average single droplet volume is 8630.7 µm. 3 With a laser frequency of 80kHz, its ideal transfer efficiency can reach 2485.62mm. 3 / h can achieve a stable and high-throughput transfer effect.

[0061] Example 4 A. Prepare the transfer film and the receptor substrate; The solid film is prepared by depositing nickel on the surface of a polyethylene terephthalate film by magnetron sputtering to form an amorphous nickel film with a thickness of 20 nm; and electroplating copper on the surface of the amorphous nickel film with a thickness of 20 nm to form a tin film with a thickness of 6 μm and an average grain size of 400 nm, thus obtaining a solid film. B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 100 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 4.5 J / cm². 2 .

[0062] The layered structure of the transfer film, from top to bottom, is shown in the table below:

[0063] Tin has a much lower melting point than copper. Under the same thickness conditions, the latent heat required to induce a solid-liquid phase transition in the tin film will be significantly reduced, meaning that the peak energy flux density required to transfer the tin film is lower.

[0064] In this embodiment, the calculated average single droplet volume is 3018.25 μm. 3 With a laser frequency of 80kHz, its ideal transfer efficiency can reach 869.26mm. 3 / h can achieve a stable and high-throughput transfer effect.

[0065] Comparative Example 1 The preparation method, step A, and raw materials of this comparative example are the same as those of Example 1. The difference lies in the parameters of the transfer laser in step B of this comparative example. That is, step B of Comparative Example 1 is as follows: B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 2 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 0.6 J / cm². 2 .

[0066] The transfer process is as follows Figure 4 As shown, when the transfer laser uses a pulse width of 2ns, even if the peak energy flux density of the transfer laser is reduced, the laser energy is concentrated on the surface of the solid film in a very short time, causing the surface of the solid film to undergo an explosive vaporization process in a very short time, generating a violent vaporization recoil force, which causes the material to detach from the donor film by spraying or sputtering, and thus cannot form a controllable droplet.

[0067] Comparative Example 2 The preparation method, step A, and raw materials of this comparative example are the same as those of Example 1. The difference lies in the parameters of the transfer laser in step B of this comparative example. That is, step B of Comparative Example 2 is as follows: B. Apply a transfer laser to the transfer film, allowing the laser to penetrate the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate. A specific transfer device is described below. Figure 1 As shown; The transfer laser has a pulse width of 2 ns and a wavelength of 532 nm. The peak energy flux density of the transfer laser when it reaches the solid film is 0.2 J / cm². 2 .

[0068] The transfer process is as follows Figure 5 As shown, when the pulse energy of the transfer laser is too low, the transfer process is as follows: Figure 5 As shown, the solid film only experienced surface thermal stress accumulation and micro-region deformation, and the surface of the acceptor substrate showed a slightly raised small bump structure, with no complete material transfer observed.

[0069] Comparative Example 3 The preparation method, step A, and raw materials of this comparative example are the same as those of Example 1. The difference is that the flexible transparent substrate is replaced with transparent glass in this comparative example.

[0070] The transfer process is as follows Figure 6As shown, when transparent glass is used as the substrate for the solid film, the transfer laser energy penetrates the transparent glass and acts directly on the interface between it and the solid film. Due to the high thermal stability of transparent glass, the interface only softens and does not undergo thermal decomposition like a flexible transparent substrate. Therefore, during the transfer process, the system lacks a gentle pressure driving force to propel the molten droplets away. Simultaneously, the high thermal conductivity and rapid heat diffusion of transparent glass cause heat to be quickly drawn away, preventing accumulation and resulting in only localized melting of the solid film to form a molten pool. At this point, due to the lack of effective back pressure to peel it away, the molten droplets ultimately deform in situ or re-solidify, making effective transfer difficult.

[0071] If the energy flux density is increased during the transfer process, its evolution will be similar to... Figure 4 Similarly, the metal layer at the interface will rapidly absorb energy and undergo explosive vaporization, thereby generating a violent vaporization recoil force that causes the material to detach from the solid film by jetting or sputtering, making it impossible to form controllable molten droplets.

[0072] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A high-throughput transfer method for solid thin films, characterized in that, Includes the following steps: A. Prepare the transfer film and the receptor substrate; The transfer film includes a flexible transparent substrate and a solid film adhered to the inner surface of the flexible transparent substrate; The thickness of the solid film is 2 to 20 μm; the solid film includes a first metal film and a second metal film bonded together, the first metal film being in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film being ≤500 nm. B. Apply a transfer laser to the transfer film, allowing the transfer laser to pass through the flexible transparent substrate and irradiate the solid film, causing the solid film to melt, transfer, and deposit onto the acceptor substrate; The pulse width of the transfer laser is 60–300 ns, and the wavelength is ≥500 nm.

2. The high-throughput transfer method for solid thin films according to claim 1, characterized in that, In step B, the pulse width of the transfer laser is 120–300 ns.

3. The high-throughput transfer method for solid thin films according to claim 1, characterized in that, In step A, the solid film includes a first metal film and a second metal film bonded together, the first metal film being in contact with the inner surface of the flexible transparent substrate, and the thickness of the first metal film being ≤500nm. The first metal film is deposited from a first metal; The second metal film is formed by depositing a second metal; When the first metal and the second metal are of the same type, and both the first metal and the second metal are crystalline structures, the average grain size of the first metal and the second metal are different. Alternatively, when the first metal and the second metal are of the same type, the first metal is amorphous and the second metal is crystalline.

4. The high-throughput transfer method for solid thin films according to claim 3, characterized in that, The first metal is any one of copper, titanium, chromium, nickel, tin, copper alloy, titanium alloy, chromium alloy, nickel alloy, and tin alloy; The second metal is any one of copper, tin, silver, gold, copper alloy, tin alloy, silver alloy, and gold alloy; The peak energy flux density of the transfer laser when it reaches the solid film is 1–220 J / cm². 2 .

5. The high-throughput transfer method for solid thin films according to claim 3, characterized in that, In step A, the method for preparing the solid film is as follows: A first metal thin film is formed by depositing a first metal on the surface of a flexible transparent substrate; A second metal film is formed by electroplating or chemical plating a second metal on the surface of the first metal film, thus obtaining a solid film.

6. The high-throughput transfer method for solid thin films according to claim 1, characterized in that, In step A, the thickness of the flexible transparent substrate is 5–200 μm.

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