Film preparation process

Abstract

The invention provides a thin film preparation process, and belongs to the technical field of thin film materials. The thin film preparation process comprises the steps that a first structural body is provided, the first structural body comprises a target material layer and two sets of metal layers combined to the two opposite surfaces of the target material layer respectively, and the thermal expansion coefficient of the metal layers is larger than that of the target material layer; and heating the first structural body, so that the interior of the target material layer is cracked and cracks are formed, and a second structural body is obtained. And post-processing the second structural body to obtain the non-flexible film. When the interior of the target material layer is cracked, the target material layer is subjected to tensile stress applied by the metal layer, and the tensile stress is adjusted by adjusting at least one of the following parameters: a difference value of thermal expansion coefficients of the metal layer and the target material layer, a thickness value of the metal layer and a temperature value applied to the first structural body after heating treatment. The film preparation process has the advantages of high film preparation efficiency, low cost, high film quality and low loss.

Description

Technical Field

[0001] The present disclosure relates to the technical field of thin film materials, and in particular to a thin film preparation process. Background Art

[0002] For crystalline materials such as lithium niobate, lithium tantalate, diamond, and silicon carbide, ion implantation and stripping processes, laser slicing processes, etc. are usually used to slice them to obtain thin films with larger areas.

[0003] For example, ion implantation stripping is commonly used for crystalline materials like lithium niobate and lithium tantalate. However, this process has at least the following drawbacks: low slicing efficiency, high cost, and the semiconductor film is susceptible to inheriting defects caused by ion implantation. For crystalline materials like diamond and silicon carbide, laser slicing is commonly used. However, this process has at least the following drawbacks: low slicing efficiency, high cost, internal damage to the semiconductor film, and high semiconductor material loss (because the kerf width increases with increasing laser cutting depth).

[0004] It can be seen that it is very necessary to provide a thin film preparation process with high film preparation efficiency, low cost, high film quality and low loss.

[0005] Public content

[0006] The embodiments of the present disclosure provide a thin film preparation process that can solve the technical problems existing in the related art. Specifically, the technical solution is as follows.

[0007] A thin film preparation process, comprising:

[0008] Providing a first structure, the first structure comprising a target material layer, and two sets of metal layers respectively bonded to two opposite surfaces of the target material layer, wherein the thermal expansion coefficient of the metal layers is greater than the thermal expansion coefficient of the target material layer;

[0009] performing a temperature treatment on the first structure so that the interior of the target material layer cracks and forms cracks, thereby obtaining a second structure;

[0010] performing post-processing on the second structure to obtain a non-flexible film, wherein the non-flexible film is derived from the cracked target material layer;

[0011] Among them, when the target material layer cracks internally, it is subjected to tensile stress applied by the metal layer, and the magnitude of the tensile stress is adjusted by adjusting at least one of the following parameters: the difference in thermal expansion coefficient between the metal layer and the target material layer, the thickness of the metal layer, and the temperature value applied to the first structure after the heating treatment.

[0012] The thin film fabrication process provided by the present disclosure comprises bonding metal layers to two opposing surfaces of a target material layer to form a first structure. The first structure is then subjected to a temperature treatment. Because the thermal expansion coefficient of the metal layer is greater than that of the target material layer, the metal layer generates thermal expansion stress that acts on the interior of the target material layer, thereby applying a tensile stress to the target material layer. By adjusting at least one of the difference in thermal expansion coefficients between the metal layer and the target material layer, the thickness of the metal layer, and the temperature applied to the first structure after the temperature treatment, the magnitude of the tensile stress can be adjusted, thereby causing cracks to form a second structure with cracks within the target material layer. Furthermore, by post-processing the second structure, a relatively thin, non-flexible film can be easily obtained based on the target material layer. The thin film fabrication process provided by the present disclosure comprises a process for fabricating a non-flexible film by sequentially depositing a metal layer, performing a heat treatment, and performing a simple post-treatment on the target material layer. The process is simple and easy to operate, and can rely on mature related process equipment, resulting in high efficiency and low cost film fabrication.

[0013] Furthermore, during the process of cracking the target material layer due to the tensile stress caused by thermal expansion, no substance, such as ions or lasers, penetrates the target material layer, thus preventing changes to the internal structure of the target material layer. Furthermore, the tensile stress caused by thermal expansion applied to the interior of the target material layer does not damage the target material layer. Compared to radiation damage caused by ion implantation and stripping processes, and modification damage or thermal damage caused by laser stripping processes, the thin film preparation process provided by the disclosed embodiments effectively avoids damage to the target material layer while also reducing material loss, thereby facilitating the production of high-quality, non-flexible thin films.

[0014] The thin film preparation process provided by the embodiments of the present disclosure significantly reduces the difficulty of preparing thin wafer-level films or panel-level films, especially those with larger surface areas (the surface area size can be unlimited). Therefore, the thin film preparation process provided by the embodiments of the present disclosure can achieve large-scale and low-cost film production.

[0015] In some possible implementations, the crack runs through the entire target material layer, so that the second structure is formed into two separate bodies, wherein each second structure includes a target material thin film layer and the metal layer bonded to a surface of the target material thin film layer facing away from the fracture surface;

[0016] Correspondingly, the post-processing of the second structure to obtain the non-flexible film includes: performing surface treatment on at least one of the two second structures to remove the metal layer, and obtaining the non-flexible film based on the target material film layer.

[0017] In some other possible implementations, the crack penetrates a portion of the target material layer, so that the second structure is formed into one;

[0018] Accordingly, the post-processing of the second structure to obtain a non-flexible film comprises:

[0019] Slicing the non-cracked portion of the target material layer along the crack to obtain two third structures separated from each other, each of the third structures comprising a target material film layer and the metal layer bonded to a surface of the target material film layer facing away from the fracture surface;

[0020] At least one of the two third structures is surface-treated so that the metal layer is removed, and the non-flexible film is obtained based on the target material film layer.

[0021] In some possible implementations, the cracking position of the target material layer is adjusted by adjusting at least one of the following parameters: the thickness of at least one of the two groups of metal layers, and the thermal expansion coefficient of at least one of the two groups of metal layers.

[0022] When the tensile stresses applied by the two groups of metal layers located on the first surface and the second surface of the target material layer are the same, the cracking position of the target material layer is located in the middle position thereof. Conversely, when the tensile stresses applied by the two groups of metal layers located on the first surface and the second surface of the target material layer are different, the cracking position of the target material layer is closer to the metal layer that applies greater tensile pressure.

[0023] In some possible implementations, the two groups of metal layers have the same thermal expansion coefficient and the same thickness, and the crack position is centrally located in the target material layer.

[0024] In some possible implementations, the two groups of metal layers have the same thermal expansion coefficient and different thicknesses, and the cracking location is close to a side of the target material layer that is combined with the metal layer with a larger thickness.

[0025] In some possible implementations, the temperature increase treatment includes: providing a heat treatment environment with a preset temperature; and placing the first structure in the heat treatment environment to perform the temperature increase treatment.

[0026] The first structure is placed in a preset temperature atmosphere. The temperature of the first structure can usually be raised from room temperature to the preset temperature in 3-5 minutes, which significantly reduces the preparation process time and enables the cracking of the target material layer to be completed efficiently within a time period of minutes, thereby improving work efficiency.

[0027] In some possible implementations, the preset temperature is 150°C-800°C.

[0028] In some possible implementations, each group of the metal layers is arranged as a single layer or a multi-layer arrangement;

[0029] The multilayered metal layer comprises at least a first metal layer and a second metal layer arranged in a stacked manner, wherein the first metal layer is further bonded to the target material layer and is used to increase the bonding force between the target material layer and the second metal layer.

[0030] In some possible implementations, providing a first structure includes:

[0031] performing surface treatment on the target material layer;

[0032] The metal layer is formed on the surface of the target material layer after surface treatment by using a metal material through an electroplating process or a thin film deposition process to obtain the first structure.

[0033] In some possible implementations, the target material layer is a brittle material, and the brittle material includes an amorphous brittle material, a single crystal brittle material, or a polycrystalline brittle material.

[0034] In some possible implementations, the metal material corresponding to the metal layer is selected from at least one of copper, chromium, nickel, aluminum, zinc, tungsten, tin, zirconium, titanium, and magnesium.

[0035] In some possible implementations, the thin film preparation process includes multiple cyclic operations, wherein the cyclic operations include sequentially performing a metal layer formation operation and a temperature increase treatment operation, so as to reduce the thickness of the non-flexible thin film to a set thickness threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the cracking principle of an exemplary target material layer provided in an embodiment of the present disclosure;

[0037] Figure 2 A flow chart of an exemplary thin film preparation process provided in an embodiment of the present disclosure;

[0038] Figure 3 A partial flow chart of another exemplary thin film preparation process provided in an embodiment of the present disclosure;

[0039] Figure 4 A flow chart of another exemplary thin film preparation process provided in an embodiment of the present disclosure;

[0040] Figure 5 A wireframe diagram of an exemplary thin film preparation process provided in accordance with an embodiment of the present disclosure;

[0041] Figure 6 A wireframe diagram of another exemplary thin film preparation process provided in accordance with an embodiment of the present disclosure;

[0042] Figure 7 A wireframe diagram of another exemplary thin film preparation process provided in an embodiment of the present disclosure;

[0043] Figure 8 A photograph of the cracked second structure provided in Example 1;

[0044] Figure 9 This is a microscope image of the cracked second structure provided in Example 1.

[0045] The reference numerals represent:

[0046] 100, target material layer; 101, target material film layer; 1000, non-flexible film;

[0047] 200. Metal layer. DETAILED DESCRIPTION

[0048] In the description of the embodiments of the present disclosure, the terms "upper", "lower", "thickness", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the embodiments of the present disclosure.

[0049] Solid materials can be sliced ​​through thin film preparation processes to obtain thin films of a certain thickness, especially thin films with larger planar dimensions. Currently known thin film preparation processes include ion implantation and stripping processes, laser slicing processes, etc.

[0050] The ion implantation stripping process involves injecting ions into the solid material to be stripped, creating a damaged layer at a specific location within the solid material. The damaged layer is then annealed, heated, or otherwise treated to decompose the damaged layer, allowing the film to be stripped from the solid material. However, the ion implantation stripping process has at least the following disadvantages: low slicing efficiency, high cost (the ion implantation equipment is expensive and the process is complex), and the semiconductor film is susceptible to inheriting defects caused by the ion implantation.

[0051] The laser slicing process irradiates the solid material to be peeled off with a laser, thereby breaking the solid material at a specific position inside it. However, the laser slicing process has at least the following disadvantages: low slicing efficiency, high cost, easy internal damage to the semiconductor film, large loss of semiconductor material (because as the laser cutting depth increases, the cutting seam width also increases), etc., which is not conducive to the preparation of thin wafer-level films or panel-level films.

[0052] It can be seen that it is necessary to make the thin film preparation process have the following advantages: high film preparation efficiency, low cost, high film quality, low loss, etc., which is very necessary for the large-scale application of the thin film preparation process.

[0053] In view of the technical problems existing in the related art, the present disclosure provides a thin film preparation process, as shown in the attached Figure 5 As shown, the film preparation process includes the following steps:

[0054] Step S1 : providing a first structure, the first structure comprising a target material layer and two sets of metal layers respectively bonded to two opposite surfaces of the target material layer, wherein the thermal expansion coefficient of the metal layer is greater than the thermal expansion coefficient of the target material layer.

[0055] Step S2: performing a temperature-raising treatment on the first structure so that the interior of the target material layer is cracked and cracks are formed, thereby obtaining a second structure.

[0056] Step S3: performing post-processing on the second structure to obtain a non-flexible film, wherein the non-flexible film comes from the cracked target material layer.

[0057] Among them, when the target material layer cracks internally, it is subjected to tensile stress applied by the metal layer. The magnitude of the tensile stress is adjusted by adjusting at least one of the following parameters: the difference in thermal expansion coefficient between the metal layer and the target material layer, the thickness of the metal layer, and the temperature value applied to the first structure after the heating treatment.

[0058] The "non-flexible film" involved in the embodiments of the present disclosure includes at least a hard film. In some examples, the hard film may also be a hard film with a brittle characteristic. The brittle characteristic may be considered to be a hard film with an elongation of less than 5%.

[0059] In order to prepare a non-flexible film, one embodiment may be to make the target material layer a non-flexible material, such as a hard material, or further a brittle material, wherein the brittle material may be a material with an elongation of less than 5%.

[0060] Combined with attachment Figure 1 Taking the target material layer as a non-flexible material as an example, the cracking mechanism of the target material layer is explained as follows:

[0061] As attached Figure 1 As shown in part a of FIG, in the first structure, the upper and lower surfaces of the target material layer 100 are both combined with metal layers 200 , and the thermal expansion coefficients and thicknesses of the two metal layers 200 may be the same or different.

[0062] As attached Figure 1As shown in part b, after the first structure is subjected to a temperature increase treatment, the metal layer 200 will generate thermal expansion stress. However, based on the interface bonding force between the target material layer 100 and the metal layer 200, the two restrict each other, wherein the target material layer 100 pulls the metal layer 200 (see the solid arrow in the figure), and the metal layer 200 is compressed relative to the state where the thermal stress is 0, that is, under the temperature increase environment, the interface between the target material layer 100 and the metal layer 200 does not crack.

[0063] Since the thermal expansion coefficient of the metal layer 200 is greater than the thermal expansion coefficient of the target material layer 100, the metal layer 200 will generate thermal expansion stress, and the expansion of the target material layer 100 itself is not enough to match the metal layer 200. Therefore, the metal layer 200 applies the thermal expansion stress to the interior of the target material layer 100, generating tensile stress (i.e., tensile force, see the dotted arrow in the figure) on the target material layer 100, and the target material layer 100 is stretched relative to the state of thermal stress being 0.

[0064] As attached Figure 1 As shown in part c, under the tensile stress applied by the metal layer 200, the target material layer 100 cracks. Figure 1 It is illustrated that the target material layer 100 is thermally decomposed and cracked into two parts, that is, two target material film layers 101 are formed, and at least one of the two target material film layers 101 is used to provide a non-flexible film 1000 .

[0065] Based on the above cracking mechanism of the target material layer, it can be seen that since the two groups of metal layers are located on two opposite surfaces of the target material layer, the cracks generated in the target material layer can be parallel to the plane where the metal layers are located, or they can be parallel to the plane where the metal layers are located but do not intersect, thereby promoting the target material layer to crack into upper and lower parts.

[0066] The thin film fabrication process provided by the present disclosure comprises bonding metal layers to two opposing surfaces of a target material layer to form a first structure. The first structure is then subjected to a temperature treatment. Because the thermal expansion coefficient of the metal layer is greater than that of the target material layer, the metal layer generates thermal expansion stress that acts on the interior of the target material layer, thereby applying a tensile stress to the target material layer. By adjusting at least one of the difference in thermal expansion coefficients between the metal layer and the target material layer, the thickness of the metal layer, and the temperature applied to the first structure after the temperature treatment, the magnitude of the tensile stress can be adjusted, thereby causing cracks to form a second structure with cracks within the target material layer. Furthermore, by post-processing the second structure, a relatively thin, non-flexible film can be easily obtained based on the target material layer. The thin film fabrication process provided by the present disclosure comprises a process for fabricating a non-flexible film by sequentially depositing a metal layer, performing a heat treatment, and performing a simple post-treatment on the target material layer. The process is simple and easy to operate, and can rely on mature related process equipment, resulting in high efficiency and low cost film fabrication.

[0067] Furthermore, during the process of cracking the target material layer due to the tensile stress caused by thermal expansion, no substance, such as ions or lasers, penetrates the target material layer, thus preventing changes to the internal structure of the target material layer. Furthermore, the tensile stress caused by thermal expansion applied to the interior of the target material layer does not damage the target material layer. Compared to radiation damage caused by ion implantation and stripping processes, and modification damage or thermal damage caused by laser stripping processes, the thin film preparation process provided by the disclosed embodiments effectively avoids damage to the target material layer while also reducing material loss, thereby facilitating the production of high-quality, non-flexible thin films.

[0068] The thin film preparation process provided by the embodiments of the present disclosure significantly reduces the difficulty of preparing thin wafer-level films or panel-level films, especially those with larger surface areas (the surface area size can be unlimited). Therefore, the thin film preparation process provided by the embodiments of the present disclosure can achieve large-scale and low-cost film production.

[0069] Since the target material layer is subjected to tensile stress when cracking internally, the tensile stress is applied to the target material layer by the metal layer. By adjusting at least one of the following parameters: the difference in thermal expansion coefficient between the metal layer and the target material layer, the thickness of the metal layer, and the temperature value applied to the first structure after the temperature increase treatment, the magnitude of the tensile stress applied to the target material layer can be adjusted, thereby achieving the adjustment of the degree of internal cracking of the target material layer.

[0070] The embodiment of the present disclosure adjusts the magnitude of the tensile stress applied to the target material layer by adjusting the above-mentioned parameters. This is conducive to obtaining a more suitable cracking mode for the target material layer according to actual needs, so that the thin film preparation process provided by the embodiment of the present disclosure has stronger adaptability and wider versatility. The effects brought about by this are exemplified below.

[0071] One effect of the aforementioned tensile stress adjustment scheme for the target material layer is that the tensile stress applied to the target material layer is adjusted to equal the target material layer's fracture stress threshold. The fracture stress threshold herein refers to the maximum stress value that the target material layer can withstand upon fracture. This not only causes cracking within the target material layer but also prevents further fragmentation of the target material layer after cracking.

[0072] Another effect brought about by the above-mentioned tensile stress adjustment scheme for the target material layer is that, under the premise of appropriately reducing the thickness of the metal layer (i.e., reducing metal consumables), the magnitude of the tensile stress can be adjusted by adjusting at least one of the difference in thermal expansion coefficients between the metal layer and the target material layer and the applied temperature of the heating treatment to ensure that cracks occur inside the target material layer. This not only helps to reduce the cost of consumables, but also helps to simplify the difficulty of the metal layer removal step.

[0073] Another effect brought about by the above-mentioned tensile stress adjustment scheme for the target material layer is that when the types of metal materials suitable for the target material layer are relatively limited, that is, when the adjustment range of the difference in thermal expansion coefficient between the metal layer and the target material layer is small, the tensile stress can be adjusted by adjusting at least one of the thickness value of the metal layer and the temperature value applied to the first structure after the heating treatment, thereby avoiding the inability to achieve smooth cracking of the target material layer due to the limitations of the metal material.

[0074] It can be seen that the thin film preparation process provided by the embodiment of the present disclosure is based on the pulling mechanism of the target material layer, which causes the target material layer to be split into two parts from the inside. This is different from the interface cracking method involved in related technologies, and relies on the currently mature and low-cost technical processes, making it easy to promote and apply on a large scale.

[0075] In the embodiment of the present disclosure, the thermal expansion coefficient of the metal layer depends on the type of metal material used therein, and the thermal expansion coefficient of the target material layer depends on the type of target material used therein. The thermal expansion coefficient of the metal layer is greater than the thermal expansion coefficient of the target material layer. For example, the ratio of the thermal expansion coefficient of the metal layer to the thermal expansion coefficient of the target material layer can be 2-20:1, further can be 2-10:1, further can be 2-5:1, etc.

[0076] In some examples, finite element simulation software may be used to simulate and calculate the tensile stress applied to the target material layer, thereby quickly and reliably obtaining a desired tensile stress value.

[0077] When performing finite element simulation, one or two parameters including the difference in thermal expansion coefficient between the metal layer and the target material layer, the thickness of the metal layer, and the temperature value applied to the first structure after the heating treatment can be used as constants, and the remaining parameters can be changed. A simulation model of the first structure is thus formulated, and simulation calculation of the tensile stress value is performed based on the simulation model.

[0078] An example simulation calculation can be as follows: First, the target material corresponding to the target material layer and the metal material corresponding to the metal layer are determined to obtain the difference in thermal expansion coefficients between the metal layer and the target material layer. Furthermore, the temperature applied to the first structure after the temperature increase treatment is determined, and both are set as constants. The thickness of the metal layer is used as a variable, and the tensile stress value is simulated based on the simulation model. Similarly, by changing the constant and variable types and simulating the tensile stress value based on the obtained simulation model, the relationship between the tensile stress and the aforementioned adjustment parameters can be obtained, thereby more efficiently and reliably guiding the thermal decomposition and cracking of the target material layer.

[0079] Table 1 illustrates a tensile stress simulation test result. In this simulation model, the target material layer is a glass layer, the metal layer is a copper layer, the thickness of the two sets of metal layers is the same, and the temperature applied to the first structure after the heating treatment is 260°C.

[0080] Table 1

[0081] Copper layer thickness / μm Glass layer thickness / μm Tensile stress simulation results / MPa 100 120 238 50 120 213 30 120 191 15 120 154.6 15 450 153 10 120 132 10 450 133 5 120 92 5 450 94

[0082] It can be seen from Table 1 that, under the premise that the difference in thermal expansion coefficient between the metal layer and the target material layer and the temperature applied to the first structure after the temperature increase treatment are determined, the tensile stress value of the target material layer increases with the increase in the thickness of the metal layer, and is less affected by the area of ​​the metal layer and the thickness of the target material layer.

[0083] Although the thickness of the target material layer has no significant effect on the tensile stress, in the embodiment of the present disclosure, the thickness of the target material layer can be in the micron range, for example, the thickness of the target material layer can be 50 microns to 1000 microns, and can further be 100 microns to 500 microns.

[0084] In the embodiment of the present disclosure, after the target material layer is pyrolyzed and cracked, it can be cracked into two independent parts, or it can be a part that is cracked but not divided, which are exemplified below.

[0085] In some embodiments, as shown in the accompanying Figure 2 -Attached Figure 3As shown, the crack formed by the internal cracking of the target material layer 100 penetrates the entire target material layer 100, thereby splitting the target material layer 100 into two parts (i.e., forming two target material thin film layers 101). Consequently, the second structure also consists of two parts. In other words, the crack penetrates the entire target material layer 100, forming two separate second structures, each of which includes the target material thin film layer 101 and the metal layer 200 bonded to the surface of the target material thin film layer 101 facing away from the fracture surface. The target material thin film layer 101 in the second structure, i.e., one of the two parts formed by the cracking of the target material layer 100, is used to provide the non-flexible film 1000.

[0086] Based on this embodiment, the second structure is post-processed to obtain a non-flexible film, including: performing surface treatment on at least one of the two second structures to remove the metal layer, and obtaining a non-flexible film based on a target material film layer.

[0087] By performing surface treatment on the second structure to remove the metal layer thereon, the remaining target material thin film layer can be formed directly or formed into a non-flexible thin film after further treatment.

[0088] As can be seen, in this embodiment, after heating and cooling the first structure, through-cracks can be achieved in the target material layer, resulting in a second structure comprising a thin film layer of the target material. Further removal of the metal layer from the second structure is then sufficient to obtain a non-flexible film. This embodiment is simple, efficient, and low-cost, not only facilitating large-scale implementation but also significantly reducing the difficulty of preparing larger films.

[0089] In other embodiments, the cracks formed by the internal cracking of the target material layer do not penetrate the entire target material layer. Although the target material layer has cracks, it still has an integrated structure. For example, the cracks exist in non-middle regions of the target material layer (this includes edge regions), while the central region of the target material layer is not cracked, that is, it is a non-cracked portion (this does not exclude the presence of non-through cracks in the middle region of the target material layer). In other words, the cracks penetrate part of the target material layer, and the target material layer forms the second structure into one.

[0090] Based on this embodiment, the second structure is post-processed to obtain a non-flexible film, including: slicing the non-cracked portion of the target material layer along the crack to obtain two separate third structures, each of which includes a target material film layer and a metal layer bonded to a surface of the target material film layer facing away from the fracture surface. At least one of the two third structures is surface-treated to remove the metal layer, thereby obtaining a non-flexible film based on the target material film layer. Exemplarily, slicing the non-cracked portion of the second structure can be performed using a laser slicing process.

[0091] In this embodiment, although the through-crack of the target material layer is not achieved after the first structure is subjected to a temperature increase treatment, the desired cracks are already present on the obtained second structure, which can significantly reduce the difficulty of slicing the non-cracked portion of the second structure. For example, when the non-cracked portion of the second structure is sliced ​​using a laser slicing process, although there are some undesirable losses and quality damage, the adverse effects are significantly reduced compared to laser slicing the entire target material layer. In addition, since thermal stress cracking is performed on the target material layer in the early stage, compared to laser slicing the entire target material layer, it also has the advantages of simple operation, high efficiency, and low cost. Moreover, the preparation difficulty of thin films with larger surface sizes is significantly reduced.

[0092] The thin film preparation process provided by the embodiments of the present disclosure is suitable for producing non-flexible films with relatively large surface dimensions. The surface dimensions referred to herein can be considered to be the dimensions of the surface of the target material layer where the metal layer is bonded, including but not limited to: length, width, diameter, radius, area, etc. For example, the surface dimensions of the non-flexible films produced by the embodiments of the present disclosure can be greater than or equal to 1 inch, and further can be greater than or equal to 2 inches, 3 inches, etc.

[0093] For any of the aforementioned embodiments, an example is as follows: a metal layer of a predetermined thickness is formed on two opposing surfaces of a target material layer to be stripped, thereby obtaining a first structure. The first structure is then heated and held for a predetermined time, and then rapidly cooled to room temperature, thereby obtaining a second structure.

[0094] The metal layer can be formed by electroplating or sputtering, and the first structure can be regarded as a sandwich structure system. The temperature after the heating treatment is determined according to the difference in thermal expansion coefficient and the thickness of the metal layer.

[0095] For example, if the metal material is copper, the target material is glass, and the thickness of the metal layer is 5 microns to 100 microns, the temperature applied to the first structure after the temperature increase treatment can be 245°C to 285°C. When the types of the metal material and the target material change (i.e., the difference in thermal expansion coefficient), the temperature value after the temperature increase treatment can also change accordingly. In addition, when obtaining the temperature value applied to the first structure after the temperature increase treatment, it is necessary to consider the temperature of the environment when the thermal expansion stress of the metal layer is 0, and determine the temperature increase amplitude (temperature difference) based on this. For example, when the metal layer is formed by an electroplating process, the electroplating temperature is 20°C to 60°C. On this basis, for example, the temperature of the temperature increase treatment can be determined to be the electroplating temperature + 225°C, that is, the temperature difference is 225°C, so that the temperature applied to the first structure after the temperature increase treatment is 245°C to 285°C.

[0096] In addition, the metal layer can be removed using either dry or wet etching. For larger metal layers, wet etching offers higher metal removal efficiency. The appropriate wet etching process parameters can be selected based on the specific metal material.

[0097] The surfaces of the target material layer combined with the metal layer are defined as the first surface and the second surface respectively, one group of metal layers completely covers the first surface of the target material layer, and the other group of metal layers completely covers the second surface of the target material layer, and the cracks in the target material layer can be located at any position between the first surface and the second surface of the target material layer.

[0098] The embodiment of the present disclosure can also adjust the cracking position of the target material layer by adjusting at least one of the following parameters: the thickness of at least one of the two groups of metal layers, and the thermal expansion coefficient of at least one of the two groups of metal layers.

[0099] The thickness of the metal layer and the thermal expansion coefficient of the metal layer both affect the tensile stress applied by the metal layer to the target material layer. By adjusting at least one of the two, the magnitude of the tensile stress applied by each of the two groups of metal layers can be adjusted.

[0100] When the tensile stresses applied by the two groups of metal layers located on the first surface and the second surface of the target material layer are the same, the cracking position of the target material layer is located in the middle position thereof. Conversely, when the tensile stresses applied by the two groups of metal layers located on the first surface and the second surface of the target material layer are different, the cracking position of the target material layer is closer to the metal layer that applies greater tensile pressure.

[0101] One embodiment is as shown in the attached Figure 2As shown, the two groups of metal layers 200 have the same thermal expansion coefficient and the same thickness, the crack position is centered on the target material layer 100, and the thickness of the two target material film layers 101 formed based on the target material layer 100 can be the same. At least one of the two target material film layers 101 can form a non-flexible film 1000.

[0102] Another embodiment is as shown in the attached Figure 3 As shown, the two groups of metal layers 200 have the same thermal expansion coefficient and different thicknesses. The cracking location is close to the side of the target material layer 100 that is combined with the metal layer 200 with a larger thickness. Based on the different thicknesses of the two target material film layers 101 formed by the target material layer 100, at least one of the two target material film layers 101 can form a non-flexible film 1000.

[0103] The above two groups of implementation methods make the thermal expansion coefficients of the two groups of metal layers the same, that is, the metal material type corresponding to the metal layer can remain unchanged. On this basis, the cracking position of the target material layer can be adjusted only by adjusting the thickness of the metal layer, thereby making it easier to obtain a non-flexible film with a desired thickness.

[0104] In the embodiment of the present disclosure, when the first structure is subjected to a temperature increase treatment, in order to improve the working efficiency, it is expected that the first structure can be heated up quickly. In some embodiments, the temperature increase treatment includes: providing a heat treatment environment with a preset temperature, and then placing the first structure in the heat treatment environment for temperature increase treatment.

[0105] By preheating the heat treatment environment to a preset temperature, and then placing the first structure within it, the temperature of the first structure can be rapidly raised to the same preset temperature (i.e., the temperature applied to the first structure during the heat treatment), thereby thermally decomposing and cracking the target material layer at high temperature. Testing has shown that placing the first structure in the preset temperature atmosphere typically raises the temperature of the first structure from room temperature to the preset temperature within 3-5 minutes, significantly reducing the preparation process time and enabling the cracking of the target material layer to be completed efficiently within minutes, thereby improving operational efficiency.

[0106] In some examples, the preset temperature is 150°C-800°C. Within this preset temperature range, the target material layer can be smoothly cracked while remaining within a temperature range that is not too high, thereby reducing energy consumption. Based on factors such as the type of target material layer and metal layer, and the thickness of the metal layer, a more suitable temperature range can be determined based on this preset temperature range to ensure smooth cracking of the target material layer.

[0107] In some examples, the first structure is placed in a heat treatment environment and maintained for a set time, which can be 15s-30min, and can further be: 15s-20min, 15s-10min, 15s-9min, 15s-8min, 15s-7min, 15s-6min, 15s-5min, 15s-4min, 15s-3min, 15s-2min, 15s-1min, 15s-50s, 15s-40s, 15s-30s, 15s-20s, etc., to ensure that the first structure has sufficient thermal decomposition and cracking time.

[0108] In the embodiment of the present disclosure, after the first structure is placed in a heat treatment environment with a preset temperature, the temperature of the heat treatment environment can be kept constant, or it can be kept constant for a period of time and then further increased to achieve a step-by-step temperature increase.

[0109] In some examples, the heat treatment environment can be a high-temperature furnace-type equipment, especially a furnace-type equipment with intelligent heating function, to facilitate the control of the furnace temperature. In addition, the cost of using high-temperature furnace-type equipment to complete film cracking is significantly reduced compared to ion implantation equipment, laser equipment, etc.

[0110] As described above, two opposite surfaces of the target material layer are respectively combined with a group of metal layers, wherein each group of metal layers is arranged as a single layer or a multi-layer arrangement.

[0111] For the single-layer arrangement of metal layers, one example is to use the same metal material to form a single-layer arrangement of metal layers. For example, when glass is used as the target material layer, metal copper can be used to form copper layers on two opposite surfaces of the glass, and the copper layers are a single-layer structure.

[0112] For a multilayer arrangement of metal layers, one example is to use multiple different types of metal materials to form a multilayer arrangement of metal layers. In some examples, the multilayer arrangement of metal layers includes at least a first metal layer and a second metal layer arranged in a stacked manner, wherein the first metal layer is further bonded to the target material layer, and the first metal layer is used to increase the bonding strength between the target material layer and the second metal layer.

[0113] For example, when diamond is used as the target material layer, titanium layers can be formed on two opposite surfaces of the diamond as the first metal layer using titanium metal, and then a copper layer is formed on the surface of the titanium layer away from the diamond as the second metal layer.

[0114] The titanium layer acts as a metal transition layer, and the interfacial bonding force between it and diamond is greater than the interfacial bonding force between copper and diamond, thereby ensuring that the metal layer is stably attached to the surface of the target material layer. At the same time, the thermal expansion coefficient of the copper layer is significantly greater than that of diamond, thereby providing sufficient tensile stress for the thermal decomposition and cracking of diamond.

[0115] In some examples, the multi-layered metal layer includes: a first metal layer, a second metal layer, and a third metal layer arranged in a stacked manner, the first metal layer is also bonded to the target material layer, and the first metal layer is used to increase the bonding force between the target material layer and the second metal layer.

[0116] Both the second metal layer and the third metal layer have a large thermal expansion coefficient. The thermal expansion coefficient of the second metal layer can be greater than or less than the thermal expansion coefficient of the third metal layer. By further setting the third metal layer, the thickness of the second metal layer and the preset temperature of the heat treatment environment can be made more adjustable.

[0117] For a multi-layered metal layer, in some examples, the thickness of the first metal layer can be 10 nanometers to 5 micrometers, and the thickness of the second metal layer can be adjusted according to the magnitude of the tensile stress to be applied, for example, 5 micrometers to 100 micrometers.

[0118] In the embodiment of the present disclosure, the first structure can be an existing finished product or can be obtained by self-preparation. The first structure has stronger adaptability when it is self-prepared.

[0119] In some examples, the first structure can be prepared by the following method: surface treating the target material layer; using metal material, through an electroplating process or a thin film deposition process, to form a metal layer on the surface of the surface treated target material layer to obtain the first structure.

[0120] A metal layer is directly formed on the surface of the target material layer through an electroplating process or a thin film deposition process, which is conducive to obtaining a larger interface bonding force between the metal layer and the target material layer.

[0121] For the electroplating process, appropriate electroplating parameters can be selected according to the specific metal material. For example, the electroplating temperature can be 20°C-60°C, for example, 30°C.

[0122] For forming the metal layer by a thin film deposition process, the thin film deposition process used includes but is not limited to: physical vapor deposition (PVD) and chemical vapor deposition (CVD), wherein the physical vapor deposition process includes a plasma sputtering process, etc.

[0123] In some examples, before forming the metal layer on the surface of the target material layer, the target material layer is subjected to a surface treatment to increase the interfacial bonding strength between the metal layer and the target material layer. The surface treatment includes, but is not limited to, solvent cleaning, plasma cleaning, physical decontamination, and surface etching.

[0124] For solvent cleaning treatment, the cleaning solvent used can be an acid solvent, an alkaline solvent, an organic solvent, etc., wherein the acid solvent can remove impurities such as the oxide layer on the surface of the target material layer, and the alkaline solvent can neutralize the acid solvent remaining on the surface of the target material layer. Organic solvents include but are not limited to kerosene, gasoline, benzene solvents, ketone solvents, etc., to remove impurities such as oil stains on the surface of the target material layer. For plasma cleaning treatment, it can activate the surface of the target material layer, thereby improving its surface adhesion. For physical decontamination treatment, it includes but is not limited to: polishing treatment, polishing treatment, sandblasting treatment, etc., which can remove impurities, burrs, etc. on the surface of the target material layer. For surface etching treatment, it can form a rough structure on the surface of the target material layer to increase the interface bonding strength between the metal layer and the target material layer.

[0125] In combination with any of the above-mentioned film preparation processes, a film preparation process can be referred to Figure 5 Further, another film preparation process can be found in Figure 6 The process shown, Figure 6 The thin film preparation process provided by the embodiment of the present disclosure further includes: after removing the metal layer from the second structure, performing surface treatment on the fracture surface of the obtained non-flexible thin film, wherein the surface treatment includes at least one of polishing treatment and solvent cleaning treatment.

[0126] Polishing can improve the smoothness of the fracture surface of the non-flexible film, providing a smooth and neat surface. For solvent cleaning, the cleaning solvent used can be deionized water, an organic solvent, etc. Deionized water can remove some inorganic impurities on the surface of the non-flexible film. Organic solvents, including but not limited to kerosene, gasoline, benzene solvents, ketone solvents, etc., can remove impurities such as oil stains on the surface of the target material layer, thereby ensuring a high degree of cleanliness on the surface of the non-flexible film.

[0127] The thin film preparation process involved in the embodiment of the present disclosure can be a single operation, that is, step S1 to step S3 are performed step by step in a single operation. Alternatively, the thin film preparation process can also include multiple cycle operations, such as the following Figure 4 Or attach Figure 7 As shown, the cyclic operation includes a metal layer forming operation and a temperature increasing treatment operation performed sequentially, so as to reduce the thickness of the non-flexible film to a set thickness threshold.

[0128] For multiple loop operations, see Figure 4 After completing step S2 and obtaining the second structure, if the thickness of the obtained target material film layer 101 is relatively thick, a metal layer 200 can be further formed on the fracture surface of the second structure, and then a temperature increase treatment is performed to further crack the target material film layer 101 into two parts. The process is repeated in sequence, and finally the thickness of the prepared non-flexible film 1000 is reduced to a set thickness threshold.

[0129] For any of the above-mentioned thin film preparation processes, the target material layer may be a brittle material, and the brittle material includes but is not limited to an amorphous brittle material, a single crystal brittle material, a polycrystalline brittle material, and the like.

[0130] For example, amorphous brittle materials include glass, single-crystal brittle materials include lithium niobate, lithium tantalate, diamond, silicon carbide, single-crystal silicon, gallium arsenide, gallium nitride, etc., and polycrystalline brittle materials include polycrystalline silicon, etc. It can be seen that the thin film preparation process provided by the embodiments of the present disclosure has great application potential for the preparation of single-crystal semiconductor thin films and can be widely used in optoelectronic integration fields such as III-V.

[0131] For any of the aforementioned thin film fabrication processes, the metal material corresponding to the metal layer can be selected from at least one of copper, chromium, nickel, aluminum, zinc, tungsten, tin, zirconium, titanium, and magnesium. The two sets of metal layers located on either side of the target material layer can have the same or different materials and layer structures.

[0132] In combination with the target materials and metal materials involved above, some implementation plans are given below. In the following implementation plans, the materials and layer structures of the metal layers on both sides of the target material layer are the same.

[0133] In some embodiments (1), a preparation process for a glass film is provided, wherein the target material layer is glass, the metal layer is arranged in a single layer, the metal layer can be a copper layer, a nickel layer, an aluminum layer, etc., the thickness of the metal layer can be 5 microns to 30 microns, and, when performing heat treatment, the first structure is placed in a heat treatment environment with a preset temperature of 150°C to 300°C, and the constant temperature is maintained for more than 15 seconds, for example, 20 seconds to 60 seconds.

[0134] For example, when preparing a glass film, if the metal layer is a copper layer, the thickness of the metal layer can be 10 to 30 microns, and the preset temperature of the heat treatment environment can be 240°C to 300°C. If the metal layer is a nickel layer or an aluminum layer, the thickness of the metal layer can be 5 to 15 microns, and the preset temperature of the heat treatment environment can be 150°C to 300°C, or further 150°C to 200°C.

[0135] In some embodiments (2), a process for preparing a diamond film is provided, wherein the target material layer is diamond, the metal layer is a multilayer arrangement, and the metal layer includes a combined first metal layer, a second metal layer and an optional third metal layer, and the first metal layer is also bonded to the surface of the diamond.

[0136] The first metal layer can be a titanium layer, a chromium layer, a tungsten layer, etc., and its thickness can be 10 nanometers to 5 microns; the second metal layer can be a copper layer, a nickel layer, etc., and its thickness can be 1 micron to 50 microns; the third metal layer can be a nickel layer, an aluminum layer, etc., and its thickness can be 1 micron to 50 microns, etc.

[0137] To give a further example, for the preparation of diamond films, some arrangements of the metal layers include but are not limited to the following: Ti / Cu, Cr / Cu, W / Cu, Ti / Ni, Ti / Cu / Ni, Cr / Cu / Ni, Ti / Cu / Al (the layer structure of the above metal layers is the first metal layer / the second metal layer, or the first metal layer / the second metal layer / the third metal layer).

[0138] When the metal layer includes a first metal layer and a second metal layer arranged in a stacked manner, and the second metal layer is a copper layer, the thickness of the second metal layer can be 40 microns to 50 microns, and the preset temperature of the heat treatment environment can be greater than or equal to 500°C, for example, 500°C to 800°C, 500°C to 700°C, 500°C to 600°C, etc.

[0139] When the metal layer includes a first metal layer, a second metal layer, and a third metal layer arranged in a stacked manner, and the second metal layer is a copper layer, the thickness of the second metal layer can be 1 micron to 10 microns (for example, 1 micron to 5 microns), and the thickness of the third metal layer can be 1 micron to 50 microns (for example, 20 microns to 50 microns). The preset temperature of the heat treatment environment can be greater than or equal to 350°C, for example, 350°C to 700°C, 350°C to 600°C, 350°C to 500°C, etc. For example, the arrangement of the metal layers is Cr / Cu / Ni, the thickness of the Cr layer is 100 nanometers, the thickness of the Cu layer is 2 microns, the thickness of the Ni layer is 30 microns, and the preset temperature of the heat treatment environment can be 350°C to 500°C.

[0140] In some embodiments (3), a process for preparing a silicon carbide film is provided, wherein the target material layer is silicon carbide, and the metal layer is a multilayer arrangement, the metal layer including a first metal layer and a second metal layer bonded together, the first metal layer also being bonded to the surface of the silicon carbide. The first metal layer can be a titanium layer, a chromium layer, a tungsten layer, a molybdenum layer, or a zirconium layer, and the second metal layer can be a copper layer, a nickel layer, an aluminum layer, a tin layer, or the like. For example, some arrangements of the metal layers include, but are not limited to, the following: Ti / Cu, Ti / Cu, Ti / Ni, Ti / Al, Ti / Sn, and the like.

[0141] The thickness of the first metal layer may be 10 nanometers to 5 micrometers, further 10 nanometers to 2 micrometers, and the thickness of the second metal layer may be 10 micrometers to 80 micrometers, further 35 micrometers to 55 micrometers.

[0142] The preset temperature of the heat treatment environment may be greater than or equal to 300° C., for example, 300° C.-700° C., 300° C.-600° C., 300° C.-500° C., 300° C.-400° C., etc.

[0143] For example, the arrangement of the metal layer is Ti / Cu, the thickness of the titanium layer is 10 nanometers to 2 micrometers, the thickness of the Cu layer is 45 micrometers to 55 micrometers, and the preset temperature of the heat treatment environment can be 300°C to 500°C.

[0144] In some embodiments (4), a preparation process for a lithium niobate thin film is provided, wherein the target material layer is lithium niobate, and the metal layer is arranged in a single layer. The metal layer can be a copper layer, a nickel layer, an aluminum layer, a tin layer, a magnesium layer, etc. The thickness of the metal layer can be 5 microns to 100 microns, and can further be 20 microns to 90 microns, 20 microns to 80 microns, 20 microns to 70 microns, 20 microns to 60 microns, 20 microns to 50 microns, 20 microns to 40 microns, 25 microns to 35 microns, etc. The preset temperature of the heat treatment environment can be greater than or equal to 350°C, for example, 350°C to 600°C, 350°C to 500°C, 350°C to 450°C, etc. Taking the metal layer as a copper layer as an example, its thickness can be 30 microns, and the preset temperature of the heat treatment environment can be 400°C.

[0145] In some embodiments (5), a preparation process for a lithium tantalate thin film is provided, wherein the target material layer is lithium tantalate, and the metal layer is arranged in a single layer. The metal layer can be a copper layer, a nickel layer, an aluminum layer, a tin layer, a magnesium layer, etc. The thickness of the metal layer can be 5 microns to 100 microns, and can further be 20 microns to 90 microns, 20 microns to 80 microns, 20 microns to 70 microns, 20 microns to 60 microns, 20 microns to 50 microns, 20 microns to 40 microns, 25 microns to 35 microns, etc. The preset temperature of the heat treatment environment can be greater than or equal to 350°C, for example, 350°C to 600°C, 350°C to 500°C, 350°C to 450°C, etc. Taking the metal layer as a copper layer as an example, its thickness can be 30 microns, and the preset temperature of the heat treatment environment can be 400°C.

[0146] The specific embodiments of the present disclosure will be described in more detail below. Although the specific embodiments of the present disclosure are described below, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0147] Example 1

[0148] This embodiment 1 provides a process for preparing a glass film, which is obtained by the following preparation steps:

[0149] A first structure was obtained by electroplating copper layers, each 20 microns thick, on the upper and lower surfaces of a 130-micron-thick glass sheet. The first structure was placed in a high-temperature furnace at a preset temperature of 255°C and held at that temperature for 30 seconds. The temperature was then lowered and removed from the furnace, yielding two second structures. The copper layers on the second structures were then removed using a wet etching process, resulting in a 65-micron-thick glass film.

[0150] Among them, the photos of the two second structures after being baked can be seen in Figure 8 , the cross-sectional images of the two second structures under a microscope with a magnification of 500 are shown in Figure 9 .Depend on Figure 8 and Figure 9 It can be seen that the glass is non-destructively cracked, the cracked surface of the glass is flat and smooth, and the thickness of the obtained glass film is highly uniform.

[0151] Example 2

[0152] Example 2 provides a process for preparing a glass thin film. This process differs from Example 1 in that the copper layer above the glass is 10 microns thick, while the copper layer below the glass is 30 microns thick. In Example 2, the cracking of the glass layer is closer to the 30-micron copper layer. Furthermore, the glass is also non-destructively cracked, and the cracked surface is smooth and flat. The resulting glass thin film has a high degree of thickness uniformity.

[0153] Example 3

[0154] This Example 3 provides a preparation process for a glass film, which differs from Example 1 in that the first structure is placed in a high-temperature furnace with a preset temperature of 260°C, and after the second structure is initially prepared, a copper layer with a thickness of 20 microns is electroplated on the fracture surface of the second structure, and then placed in a high-temperature furnace with a preset temperature of 260°C. The cycle is repeated in sequence, and the thickness of the electroplated copper layer is appropriately changed during subsequent cycles until a glass film with a thickness of 10 microns is obtained. Finally, the glass is also non-destructively cracked, and the cracked surface of the glass is flat and smooth. The thickness of the obtained glass film is highly uniform.

[0155] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solutions of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A thin film preparation process, characterized in that: The film preparation process comprises: Providing a first structure, the first structure comprising a target material layer, and two sets of metal layers respectively bonded to two opposite surfaces of the target material layer, wherein the thermal expansion coefficient of the metal layers is greater than the thermal expansion coefficient of the target material layer; performing a temperature treatment on the first structure so that the interior of the target material layer cracks and forms cracks, thereby obtaining a second structure; performing post-processing on the second structure to obtain a non-flexible film, wherein the non-flexible film is derived from the cracked target material layer; Among them, when the target material layer cracks internally, it is subjected to tensile stress applied by the metal layer, and the magnitude of the tensile stress is adjusted by adjusting at least one of the following parameters: the difference in thermal expansion coefficient between the metal layer and the target material layer, the thickness of the metal layer, and the temperature value applied to the first structure after the heating treatment.

2. The thin film preparation process according to claim 1, characterized in that: The crack penetrates the entire target material layer, so that the second structure is formed into two separated from each other, wherein each second structure includes a target material thin film layer and the metal layer bonded to a surface of the target material thin film layer away from the fracture surface; Correspondingly, the post-processing of the second structure to obtain the non-flexible film includes: performing surface treatment on at least one of the two second structures to remove the metal layer, and obtaining the non-flexible film based on the target material film layer.

3. The thin film preparation process according to claim 1, characterized in that: The crack penetrates a portion of the target material layer, so that the second structure is formed into one; Accordingly, the post-processing of the second structure to obtain a non-flexible film comprises: Slicing the non-cracked portion of the target material layer along the crack to obtain two third structures separated from each other, each of the third structures comprising a target material film layer and the metal layer bonded to a surface of the target material film layer facing away from the fracture surface; At least one of the two third structures is surface-treated so that the metal layer is removed, and the non-flexible film is obtained based on the target material film layer.

4. The thin film preparation process according to any one of claims 1 to 3, characterized in that: The cracking position of the target material layer is adjusted by adjusting at least one of the following parameters: the thickness of at least one of the two groups of metal layers, and the thermal expansion coefficient of at least one of the two groups of metal layers.

5. The thin film preparation process according to claim 4, characterized in that: The two groups of metal layers have the same thermal expansion coefficient and the same thickness, and the crack position is centrally located in the target material layer.

6. The thin film preparation process according to claim 4, characterized in that: The two groups of metal layers have the same thermal expansion coefficient and different thicknesses, and the crack position is close to the side of the target material layer that is combined with the metal layer with a larger thickness.

7. The thin film preparation process according to any one of claims 1 to 6, characterized in that: The temperature raising treatment includes: providing a heat treatment environment with a preset temperature; The first structure is placed in the heat treatment environment to perform the temperature increase treatment.

8. The thin film preparation process according to claim 7, characterized in that: The preset temperature is 150°C-800°C.

9. The thin film preparation process according to any one of claims 1 to 8, characterized in that: Each group of metal layers is arranged in a single layer or in multiple layers; The multilayered metal layer comprises at least a first metal layer and a second metal layer arranged in a stacked manner, wherein the first metal layer is further bonded to the target material layer and is used to increase the bonding force between the target material layer and the second metal layer.

10. The thin film preparation process according to any one of claims 1 to 9, characterized in that: The first structure is provided, comprising: performing surface treatment on the target material layer; The metal layer is formed on the surface of the target material layer after surface treatment by using a metal material through an electroplating process or a thin film deposition process to obtain the first structure.

11. The thin film preparation process according to any one of claims 1 to 10, characterized in that: The target material layer is a brittle material, and the brittle material includes an amorphous brittle material, a single crystal brittle material or a polycrystalline brittle material.

12. The thin film preparation process according to claim 11, characterized in that: The metal material corresponding to the metal layer is selected from at least one of copper, chromium, nickel, aluminum, zinc, tungsten, tin, zirconium, titanium, and magnesium.

13. The thin film preparation process according to any one of claims 1 to 12, characterized in that: The film preparation process includes multiple cyclic operations, wherein the cyclic operations include a metal layer forming operation and a temperature increasing operation performed in sequence, so as to reduce the thickness of the non-flexible film to a set thickness threshold.

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