Bonding structure, substrate and preparation method of bonding structure

Abstract

The invention provides a bonding structure, a substrate and a preparation method of the bonding structure. The bonding structure comprises a first stacked sheet, a second stacked sheet, a bonding layer and a first anti-reflection layer, the bonding layer is deposited between the first stacking piece and the second stacking piece so as to bond the first stacking piece and the second stacking piece; the first anti-reflection layer is laid on the face, back to the second stacking piece, of the first stacking piece. Wherein the refractive index of the first anti-reflection layer is smaller than that of the first stacked sheet. According to the bonding structure, the first anti-reflection layer with the lower refractive index is prepared on the first stacking sheet, so that the laser transmittance in the de-bonding process is improved. Therefore, the energy waste is reduced, and the utilization rate of the laser is improved. Therefore, the bonding knowing efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor chip manufacturing, and in particular to a bonding structure, a substrate, and a method for preparing the bonding structure. Background Art

[0002] Bonding is a method that effectively improves device performance by stacking substrates. It can achieve precise stacking of silicon wafers thinned to tens of microns or even several microns. Since silicon wafers (also called substrates) are fragile, the thinned substrates need to be adhered to a carrier with a certain rigidity. This adhesion process is called bonding. The bonded substrates and the supporting carrier complete a series of subsequent processes together. When the process is completed, the substrate needs to be separated from the supporting carrier. This process is called debonding.

[0003] At present, the commonly used debonding method is to use laser to irradiate the carrier. After the laser passes through the carrier, the bonding material absorbs energy, and the bonding material vaporizes or expands rapidly, thereby achieving debonding. From the principle of optics, we know that if a beam of light is incident from the air into an object, due to the difference in refractive index between the two materials, the light will be reflected at their interface. The refractive index difference between the object and the air determines the strength of the reflection. If the refractive index difference between the materials on both sides of the interface is smaller, less light energy will be reflected at the interface, and more light energy will enter the object. On the contrary, more light energy will be reflected back into the air and cannot enter the object, resulting in waste.

[0004] However, the current bonding structure is not able to solve the above problems well, resulting in the bonding efficiency being not high enough. Summary of the invention

[0005] The purpose of the present application is to provide a bonding structure, a substrate and a method for preparing the bonding structure, which can improve the transmittance of the laser and thus improve the efficiency of debonding.

[0006] In a first aspect, the present application provides a bonding structure, comprising a first stacked sheet, a second stacked sheet, a bonding layer and a first anti-reflection layer; the bonding layer is deposited between the first stacked sheet and the second stacked sheet to bond the first stacked sheet and the second stacked sheet; the first anti-reflection layer is prepared on a side of the first stacked sheet facing away from the second stacked sheet; wherein the refractive index of the first anti-reflection layer is less than the refractive index of the first stacked sheet.

[0007] The above bonding structure improves the transmittance of laser light during the debonding process by preparing a first anti-reflection layer with a lower refractive index on the first stacked sheet, thereby reducing energy waste and improving the utilization rate of laser energy, thereby improving the debonding efficiency.

[0008] In combination with the first aspect, optionally, the thickness of the first anti-reflection layer is determined according to the following formula:

[0009]

[0010] In the formula, d represents the thickness of the first anti-reflection layer; λ represents the wavelength of the laser used in the process of debonding the first stacked sheet and the second stacked sheet; m is an integer multiple of the wavelength of the laser; and n represents the refractive index of the first anti-reflection layer.

[0011] The above bonding structure, through the thickness of the first anti-reflection layer determined by the above calculation formula, can further reduce the reflection of the laser during the debonding process, thereby further improving the transmittance of the laser, that is, further improving the debonding efficiency.

[0012] In combination with the first aspect, optionally, m=1.

[0013] The bonding structure described above further determines the thickness of the first anti-reflection layer calculated by the calculation formula of the first anti-reflection layer. The use of this thickness will increase the transmittance of the laser, thereby further improving the efficiency of debonding.

[0014] In combination with the first aspect, optionally, the material of the first anti-reflection layer includes silicon dioxide.

[0015] The above bonding structure uses silicon dioxide as the material of the first anti-reflection layer, so that the reflection loss on the surface of the first anti-reflection layer is reduced to 3.4%, that is, the transmittance of the laser is further improved, thereby further improving the efficiency of debonding.

[0016] In combination with the first aspect, optionally, the structure further includes a second anti-reflection layer; the second anti-reflection layer is deposited on a side of the first anti-reflection layer facing away from the first stacked sheet; wherein the refractive index of the second anti-reflection layer is lower than the refractive index of the first anti-reflection layer.

[0017] The above bonding structure further improves the transmittance of laser by adding a second anti-reflection layer on the first anti-reflection layer, thereby further improving the efficiency of debonding.

[0018] In combination with the first aspect, optionally, the first stacked sheet includes a silicon support carrier, and the second stacked sheet includes a semiconductor substrate.

[0019] The above-mentioned bonding structure improves the efficiency of debonding the bonding structure during the semiconductor chip manufacturing process by applying the bonding structures provided by the previous embodiments of the present application to the semiconductor chip manufacturing process.

[0020] In a second aspect, the present application provides a substrate comprising the bonding structure described in the first aspect.

[0021] The above-mentioned substrate has the same beneficial effects as the bonding structure described in the first aspect, which will not be described in detail here.

[0022] In a third aspect, the present application provides a method for preparing a bonding structure, comprising: bonding a first stacked sheet and a second stacked sheet via a bonding layer; and preparing a first anti-reflection layer on a side of the first stacked sheet facing away from the second stacked sheet.

[0023] The method for preparing the above bonding structure has the same beneficial effects as the bonding structure described in the first aspect, and will not be described in detail here.

[0024] In combination with the third aspect, optionally, the material of the first anti-reflection layer includes silicon dioxide; preparing the first anti-reflection layer on the side of the first stacked sheet facing away from the second stacked sheet includes: oxidizing the side of the first stacked sheet facing away from the second stacked sheet to generate the first anti-reflection layer.

[0025] The preparation method of the above-mentioned bonding structure uses the obtained silicon dioxide as the first anti-reflection layer by oxidation, thereby reducing the production cost. According to the previous description, by using silicon dioxide as the material of the first anti-reflection layer, the reflection loss on the surface of the first anti-reflection layer is reduced to 3.4%, thereby further improving the debonding efficiency.

[0026] In combination with the third aspect, optionally, preparing the first anti-reflection layer on the side of the first stacked sheet facing away from the second stacked sheet includes: depositing the first anti-reflection layer on the side of the first stacked sheet facing away from the second stacked sheet using a deposition process; wherein the deposition process includes any one of chemical vapor deposition, atomic layer deposition and physical vapor deposition.

[0027] The preparation method of the bonding structure adopts chemical vapor deposition to deposit the first anti-reflection layer, so that the thickness distribution of the first anti-reflection layer is more uniform, and the purity and density of the first anti-reflection layer are improved. That is, the deposition effect of the first anti-reflection layer is improved. By adopting physical vapor deposition to prepare the first anti-reflection layer, the adhesion of the first anti-reflection layer is improved. In addition, physical vapor deposition can deposit a thin film faster, thereby improving production efficiency. By adopting atomic layer deposition to prepare the first anti-reflection layer, the temperature required in the deposition process is lower, thereby better protecting the first stacked sheet and the second stacked sheet. In addition, the thickness of the first anti-reflection layer can be controlled more accurately.

[0028] In summary, the bonding structure, substrate and bonding structure preparation method provided by each embodiment of the present application improves the transmittance of the laser during the debonding process by laying a first anti-reflection layer with a lower refractive index on the first stacked sheet, thereby improving the efficiency of the debonding. The thickness of the first anti-reflection layer determined by the calculation formula can further reduce the reflection of the laser during the debonding process. Thereby further improving the transmittance of the laser. In other words, the efficiency of the debonding is further improved. By using silicon dioxide as the material of the first anti-reflection layer, the reflection loss on the surface of the first anti-reflection layer is reduced to 3.4%, which further improves the efficiency of the debonding. By adding a second anti-reflection layer on the first anti-reflection layer, the transmittance of the laser is further improved. Thereby further improving the efficiency of the debonding. In the case where the material of the first stacked sheet is silicon, the silicon dioxide obtained by oxidation is used as the first anti-reflection layer, which reduces the production cost and further improves the efficiency of the debonding. By using chemical vapor deposition to prepare the first anti-reflection layer, the thickness distribution of the first anti-reflection layer is more uniform, and the purity and density of the first anti-reflection layer are improved. By using physical vapor deposition to prepare the first anti-reflection layer, the adhesion of the first anti-reflection layer is improved. By using atomic layer deposition to prepare the first anti-reflection layer, the temperature required during the deposition process is lower, thereby better protecting the first stacked sheet and the second stacked sheet. In addition, the thickness of the first anti-reflection layer can be controlled more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the first structure of the bonding structure provided in the embodiment of the present application;

[0031] Figure 2 A second structural schematic diagram of a bonding structure provided in an embodiment of the present application;

[0032] Figure 3 A flow chart of a method for preparing a bonding structure provided in an embodiment of the present application.

[0033] Icons: 100, bonding structure; 110, first stacked sheet; 120, second stacked sheet; 130, bonding layer; 140, first anti-reflection layer; 150, second anti-reflection layer. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0038] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] Please refer to Figure 1 , Figure 11 is a schematic diagram of the first structure of the bonding structure 100 provided in the embodiment of the present application. The bonding structure 100 provided in the embodiment of the present application may include a first stacked sheet 110, a second stacked sheet 120, a bonding layer 130 and a first anti-reflection layer 140. The bonding layer 130 may be deposited between the first stacked sheet 110 and the second stacked sheet 120 to bond the first stacked sheet 110 and the second stacked sheet 120. The first anti-reflection layer 140 may be prepared on the side of the first stacked sheet 110 facing away from the second stacked sheet 120. The refractive index of the first anti-reflection layer 140 may be less than the refractive index of the first stacked sheet 110.

[0041] The first stacked sheet 110 may be a carrier sheet in a wafer, and the second stacked sheet 120 may be a substrate in a wafer. The first stacked sheet 110 and the second stacked sheet 120 are bonded via the bonding layer 130 , and an inorganic material may be prepared on the first substrate by a deposition process, and then the second stacked sheet 120 is bonded to the bonding layer 130 .

[0042] The first anti-reflection layer 140 can be deposited on the first stacked sheet 110 by a deposition process. When the first stacked sheet 110 is made of silicon, the first stacked sheet 110 can be directly oxidized to form a layer of silicon dioxide on its surface as the first anti-reflection layer 140 .

[0043] The refractive index of the material is different, and the difficulty of light entering from the outside will be different. The higher the refractive index, the higher the reflectivity of the light entering on the surface, and the lower the transmittance. On the contrary, the lower the refractive index, the lower the reflectivity of the light entering on the surface, and the higher the transmittance.

[0044] In the above implementation process, by laying the first anti-reflection layer 140 with a lower refractive index on the first stacked sheet 110, the transmittance of the laser during the debonding process is improved, thereby reducing energy waste and improving the utilization rate of the laser, thereby improving the efficiency of the debonding.

[0045] In some optional embodiments, the thickness of the first anti-reflection layer 140 may be determined according to the following formula:

[0046]

[0047] Wherein, d represents the thickness of the first anti-reflection layer 140 . λ represents the wavelength of the laser used in the process of debonding the first stacked sheet 110 and the second stacked sheet 120 . m is an integer multiple of the wavelength of the laser. n represents the refractive index of the first anti-reflection layer 140 .

[0048] In the above implementation process, the thickness of the first anti-reflection layer 140 determined by the above calculation formula can further reduce the reflection of the laser during the debonding process, thereby further improving the transmittance of the laser, that is, further improving the efficiency of the debonding.

[0049] In some optional embodiments, m=1.

[0050] That is to say, the calculation formula for the thickness of the first anti-reflection layer 140 provided above is further determined as:

[0051]

[0052] In the above implementation process, the thickness of the first anti-reflection layer 140 is further determined by the calculation formula of the thickness of the first anti-reflection layer 140. The thickness calculated by the formula will further improve the transmittance of the laser, thereby further improving the efficiency of debonding.

[0053] In some optional embodiments, the material of the first anti-reflection layer 140 may include silicon dioxide.

[0054] Normally, the refractive index of the silicon support is 3.47, and the refractive index of air is 1.00. According to the vertical incidence reflectivity calculation formula:

[0055]

[0056] In the formula, R is the reflectivity, n1 is the refractive index of the surface material, and n0 is the refractive index of air. When the laser is incident vertically from the air to the surface of the silicon material, 30.5% of the light will be reflected into the air, and only 69.5% of the light will enter the interior of the silicon material. If a first anti-reflection layer 140 with a refractive index lower than that of silicon is added to the silicon surface, for example, the first anti-reflection layer 140 is silicon dioxide with a refractive index of 1.45. At this time, the reflection loss of light projected from the air to the surface of the first anti-reflection layer 140 is reduced to 3.4%, which shows that most of the light enters the first anti-reflection layer 140.

[0057] In the above implementation process, by using silicon dioxide as the material of the first anti-reflection layer 140, the reflection loss on the surface of the first anti-reflection layer 140 is reduced to 3.4%, that is, the transmittance of the laser is further improved, thereby further improving the efficiency of debonding.

[0058] Please refer to Figure 2 , Figure 2 1 is a schematic diagram of a second structure of the bonding structure 100 provided in an embodiment of the present application. In some optional embodiments, the structure may further include a second anti-reflection layer 150. The second anti-reflection layer 150 may be prepared on a side of the first anti-reflection layer 140 facing away from the first stacked sheet 110. The refractive index of the second anti-reflection layer 150 may be lower than the refractive index of the first anti-reflection layer 140.

[0059] When the reflection loss of the first anti-reflection layer 140 and the surface of the first stacked sheet 110 is further considered, the reflection condition of the laser on the surface of the first stacked sheet 110 can be obtained according to the following calculation formula.

[0060]

[0061] Where R is the reflectivity, n1 is the refractive index of the surface material, n0 is the refractive index of air, and n Si is the refractive index of silicon material. It can be seen that after two reflections between air and the first anti-reflection layer 140, and between the first anti-reflection layer 140 and the silicon material (first stacked sheet 110), the overall loss of the incident light is about 19.7%, that is, 80.3% of the light will enter the silicon material (first stacked sheet 110). Obviously, adding a second anti-reflection layer 150 to the first anti-reflection layer 140 increases the transmittance of the laser by about 11%.

[0062] In the above implementation process, by adding a second anti-reflection layer 150 on the first anti-reflection layer 140, the transmittance of the laser is further improved, thereby further improving the efficiency of debonding.

[0063] In some optional embodiments, the first stacked sheet 110 may include a silicon support carrier, and the second stacked sheet 120 may include a semiconductor substrate.

[0064] That is to say, the bonding structure 100 provided in the previous embodiments of the present application can be applied to the field of semiconductor chips.

[0065] In the above implementation process, by applying the bonding structure 100 provided in the previous embodiments of the present application to a substrate composed of semiconductors, the efficiency of debonding the bonding structure 100 in the semiconductor chip is improved.

[0066] Based on the same concept, an embodiment of the present application provides a substrate that may include the bonding structure 100 described above.

[0067] The above implementation process may be the same as the bonding structure 100 described above, and will not be described again here.

[0068] Please refer to Figure 3 , Figure 3 : is a flow chart of a method for preparing a bonding structure provided in an embodiment of the present application. Based on the same concept, an embodiment of the present application provides a method for preparing a bonding structure, which may include:

[0069] Step S110: bonding the first stacked sheet and the second stacked sheet via a bonding layer.

[0070] In the above step S110 , the bonding between the first stacked sheet and the second stacked sheet can be performed by chemical vapor deposition or physical vapor deposition.

[0071] Step S120: preparing a first anti-reflection layer on a side of the first stacked sheet facing away from the second stacked sheet.

[0072] In step S120, the process for preparing the first anti-reflection layer may be chemical vapor deposition, atomic layer deposition or physical vapor deposition, etc. When the first stack is made of silicon, the first stack may be directly oxidized to form a layer of silicon dioxide on its surface as the first anti-reflection layer.

[0073] The above implementation process may be the same as the bonding structure described above, and will not be repeated here.

[0074] In some optional embodiments, the material of the first anti-reflection layer may include silicon dioxide.

[0075] Accordingly, step S120 may include:

[0076] Step S121: oxidizing a surface of the first stacked sheet facing away from the second stacked sheet to form a first anti-reflection layer.

[0077] The above step S121, that is, when the material of the first stacked sheet is silicon, the first anti-reflection layer of silicon dioxide is obtained by oxidizing the first stacked sheet. A specific implementation method for oxidizing the first stacked sheet may be that after the first stacked sheet is chemically cleaned, it is placed in an oxidation furnace, and oxygen or water vapor may be used as an oxidant in the oxidation furnace. The temperature of the oxidation furnace may then be controlled to be between 800°C and 1200°C. The specific temperature selection may be determined by those skilled in the art based on the desired thickness of the oxide layer (that is, the first anti-reflection layer) and the growth rate. Similarly, depending on the desired thickness of the oxide layer, the oxidation time may vary from a few minutes to a few hours.

[0078] In the above implementation process, the obtained silicon dioxide is used as the first anti-reflection layer by oxidation, which reduces the production cost. According to the previous description, by using silicon dioxide as the material of the first anti-reflection layer, the reflection loss on the surface of the first anti-reflection layer is reduced to 3.4%, thereby further improving the debonding efficiency.

[0079] In some optional implementations, step S120 may include:

[0080] Step S122: depositing a first anti-reflection layer on a side of the first stacked sheet facing away from the second stacked sheet by using a deposition process.

[0081] The deposition process may include any one of chemical vapor deposition, atomic layer deposition and physical vapor deposition.

[0082] In the above implementation process, chemical vapor deposition is used to prepare the first anti-reflection layer, so that the thickness distribution of the first anti-reflection layer is more uniform, and the purity and density of the first anti-reflection layer are improved. That is, the deposition effect of the first anti-reflection layer is improved. Physical vapor deposition is used to prepare the first anti-reflection layer, and the adhesion of the first anti-reflection layer is improved. Physical vapor deposition can deposit a thin film faster, thereby improving production efficiency. Atomic layer deposition is used to prepare the first anti-reflection layer, so that the temperature required during the deposition process is lower, thereby better protecting the first stacked sheet and the second stacked sheet. And the control of the thickness of the first anti-reflection layer is more precise.

[0083] In summary, the bonding structure 100, substrate and bonding structure 100 preparation method provided by each embodiment of the present application improves the transmittance of the laser during the debonding process by laying the first anti-reflection layer 140 with a lower refractive index on the first stacked sheet 110, thereby improving the efficiency of debonding. The thickness of the first anti-reflection layer 140 determined by the calculation formula can further reduce the reflection of the laser during the debonding process. Thereby further improving the transmittance of the laser. In other words, further improving the efficiency of debonding. By using silicon dioxide as the material of the first anti-reflection layer 140, the reflection loss on the surface of the first anti-reflection layer 140 is reduced to 3.4%, which further improves the efficiency of debonding. By adding another layer of the second anti-reflection layer 150 on the first anti-reflection layer 140, the transmittance of the laser is further improved. Thereby further improving the efficiency of debonding. In the case where the material of the first stacked sheet 110 is silicon, the silicon dioxide obtained by oxidation is used as the first anti-reflection layer 140, which not only reduces the production cost, but also further improves the efficiency of debonding. By using chemical vapor deposition to deposit the first anti-reflection layer 140, the thickness distribution of the first anti-reflection layer 140 is more uniform, and the purity and density of the first anti-reflection layer 140 are improved. By using physical vapor deposition to prepare the first anti-reflection layer 140, the adhesion of the first anti-reflection layer 140 is improved. By using atomic layer deposition to prepare the first anti-reflection layer 140, the temperature required during the deposition process is lower, thereby better protecting the first stacked sheet 110 and the second stacked sheet 120. And the control of the thickness of the first anti-reflection layer 140 is more precise.

[0084] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A bonding structure, characterized in that: It includes a first stacked sheet, a second stacked sheet, a bonding layer and a first anti-reflection layer; The bonding layer is deposited between the first stacked sheet and the second stacked sheet to bond the first stacked sheet and the second stacked sheet; The first anti-reflection layer is prepared on a side of the first stacked sheet facing away from the second stacked sheet; Wherein, the refractive index of the first anti-reflection layer is smaller than the refractive index of the first stacked sheet.

2. The bonding structure according to claim 1, characterized in that: in, The thickness of the first anti-reflection layer is determined according to the following formula: In the formula, d represents the thickness of the first anti-reflection layer; λ represents the wavelength of the laser used in the process of debonding the first stacked sheet and the second stacked sheet; m is an integer multiple of the wavelength of the laser; and n represents the refractive index of the first anti-reflection layer.

3. The bonding structure according to claim 2, characterized in that: in, m＝1。 4. The bonding structure according to claim 1, characterized in that: in, The material of the first anti-reflection layer includes silicon dioxide.

5. The bonding structure according to claim 1, characterized in that: The structure also includes a second anti-reflection layer; The second anti-reflection layer is prepared on a side of the first anti-reflection layer facing away from the first stacked sheet; Wherein, the refractive index of the second anti-reflection layer is lower than the refractive index of the first anti-reflection layer.

6. The bonding structure according to any one of claims 1 to 5, characterized in that: The first stack includes a silicon support carrier, and the second stack includes a semiconductor substrate.

7. A substrate, characterized in that: Comprising the bonding structure as claimed in any one of claims 1 to 6.

8. A method for preparing a bonding structure, characterized in that: include: Bonding the first stacked sheet and the second stacked sheet via a bonding layer; A first anti-reflection layer is prepared on a side of the first stacked sheet facing away from the second stacked sheet.

9. The method according to claim 8, characterized in that in, The material of the first anti-reflection layer includes silicon dioxide; A first anti-reflection layer is prepared on a side of the first stacked sheet facing away from the second stacked sheet, comprising: The first stacked sheet is oxidized on a side facing away from the second stacked sheet to form the first anti-reflection layer.

10. The method according to claim 8, characterized in that A first anti-reflection layer is prepared on a side of the first stacked sheet facing away from the second stacked sheet, comprising: The first anti-reflection layer is deposited on a side of the first stacked sheet facing away from the second stacked sheet by a deposition process; wherein the deposition process includes any one of chemical vapor deposition, atomic layer deposition and physical vapor deposition.

Images