WO2021184171A1

WO2021184171A1 - Manufacturing method for multilayer film and multilayer film

Info

Publication number: WO2021184171A1
Application number: PCT/CN2020/079554
Authority: WO
Inventors: 秦健鹰; 杨喜超; 邢彦敏; 张岩; 魏侠
Original assignee: 华为技术有限公司
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2021-09-23
Also published as: CN115298827A

Abstract

Disclosed are a manufacturing method for a multilayer film and the multilayer film. The method primarily comprises: manufacturing a first material layer; furthermore, stacking multiple second material layers on the surface of the first material layer. In the embodiments of the present application, each second material layer comprises a second substrate, and the second substrate is constituted by a ferroelectric single crystal material. The employment of the method allows the manufacturing of multiple film layers constituted by the ferroelectric single crystal material in the multilayer film, and favors the expansion of applications of the ferroelectric single crystal material in multilayer films.

Description

Method for preparing multilayer film and multilayer film

Technical field

This application relates to the technical field of semiconductor manufacturing processes, and in particular to a method for preparing a multilayer film and a multilayer film.

Background technique

With the development of material processing technology and technology, the application of thin film materials in devices has become increasingly widespread. In particular, multi-layer films, including a plurality of stacked film layers, have applications in various semiconductor devices. For example, semiconductor devices such as lasers, memories, sensors, and capacitors are mostly composed of multilayer films.

At present, multilayer films can be prepared by growth or deposition processes. Commonly used growth or deposition processes mainly include magnetron sputtering, chemical vapor deposition, atomic layer growth, molecular beam epitaxy, and so on. However, current growth or deposition processes cannot directly prepare ferroelectric single crystal materials in multilayer films, which limits the application of ferroelectric single crystal materials in multilayer films.

Therefore, the current preparation process of multilayer films needs further study.

Summary of the invention

The present application provides a method for preparing a multilayer film and a multilayer film, which are used to prepare multiple film layers composed of ferroelectric single crystal materials in the multilayer film.

In the first aspect, an embodiment of the present application provides a method for preparing a multilayer film. The method mainly includes: preparing a first material layer, and then stacking a plurality of second material layers on the surface of the first material layer. In the embodiment of the present application, each second material layer includes a second substrate, and the second substrate is composed of a ferroelectric single crystal material.

The use of the multilayer film preparation method provided in the embodiments of the present application facilitates the preparation of multiple film layers composed of ferroelectric single crystal materials in the multilayer film. Specifically, in the embodiment of the present application, a plurality of second material layers are laminated on the surface of the first material layer, and each second material layer includes a second substrate. Therefore, the obtained multilayer film may include multiple layers made of iron. The second substrate is made of electric single crystal material, and the second substrate is made of ferroelectric single crystal material, which in turn realizes the preparation of multiple thin film layers made of ferroelectric single crystal material in a multilayer film .

Exemplarily, the ferroelectric single crystal material in the embodiments of the present application may be lithium niobate, blackened lithium niobate, doped lithium niobate, lithium tantalate, blackened lithium tantalate, doped lithium tantalate, iron Any of bismuth, barium titanate, barium strontium titanate, strontium titanate, etc.

In the embodiment of the present application, a plurality of second material layers may also be prepared first, and then a plurality of second material layers are stacked on the surface of the first material layer. It can be understood that, in addition to the second substrate, the second material layer may also include other thin film layers.

In a possible implementation manner, for each second material layer, a second intermediate layer may be prepared on the surface of the second substrate to obtain the second material layer. In the embodiments of the present application, the function of the second material layer can be flexibly designed according to application scenarios. Exemplarily, the second intermediate layer may be a sacrificial layer, a buffer layer, a contact layer, etc., which are not listed in the embodiment of the present application.

In another possible implementation, for each second material layer, a second intermediate layer can be prepared on the surface of the second substrate; continue to prepare the second bond on the surface of the second intermediate layer away from the second substrate Layer to obtain a second material layer. Some thin film materials cannot be directly bonded, or the bonding effect is not good. Therefore, the second bonding layer can be prepared to optimize the bonding effect.

In the case where the second material layer includes a second substrate and other thin film layers (such as a second intermediate layer and a second bonding layer), the first surfaces of the plurality of second material layers are all disposed toward the first material layer, wherein The first surface of each second material layer can be understood as the surface of the second material layer away from the second substrate.

Similar to preparing the second material layer, in a possible implementation manner, when preparing the first material layer, a first intermediate layer may also be prepared on the surface of the first substrate to obtain the first material layer.

In another possible implementation manner, when preparing the first material layer, the first intermediate layer can be prepared on the surface of the first substrate first, and then the first bonding layer can be prepared on the surface of the first intermediate layer away from the first substrate. Layer to obtain the first material layer.

The effects of the first intermediate layer and the first bonding layer can be referred to the second intermediate layer and the second bonding layer respectively, which will not be repeated here.

It can be understood that when the first material layer includes the first substrate and other thin film layers (such as the first intermediate layer and the first bonding layer), the multiple second material layers should be arranged on the first material layer away from the first material layer. The surface of the substrate to maintain the load of the first substrate.

In the embodiment of the present application, a third intermediate layer may be spaced between the second material layers, so as to more flexibly apply to multi-layer films of different structures. Exemplarily, in a possible implementation manner, when multiple second material layers are stacked on the surface of the first material layer, a second material layer may be provided on the surface of the first material layer, and a second material layer may be provided on the surface of the first material layer. A third intermediate layer is prepared on the surface of the second material layer, and then another second material layer is disposed on the surface of the third intermediate layer away from the second material layer that has been disposed, until the multiple second material layers are disposed.

In another possible implementation, when multiple second material layers are stacked on the surface of the first material layer, a second material layer may be provided on the surface of the first material layer; Prepare a third intermediate layer on the surface of the third intermediate layer; then prepare a third bonding layer on the surface of the third intermediate layer away from the second material layer; One second material layer until the multiple second material layers are set up.

The effects of the third intermediate layer and the third bonding layer can be referred to the second intermediate layer and the second bonding layer respectively, which will not be repeated here.

Generally speaking, there are certain requirements for the film thickness of ferroelectric single crystal materials in multilayer films. In view of this, before the third intermediate layer is prepared on the surface of the second material layer that has been provided, the second surface of the second material layer that has been provided can also be thinned to make the second material layer that has been provided The second substrate in the second material layer reaches the target thickness, where the second surface of the second material layer can be understood as the surface where the second substrate in the second material layer is located; the second surface of the second material layer that has been set is flattened Chemical treatment; afterwards, a third intermediate layer is prepared on the second surface of the second material layer.

In the second aspect, the embodiments of the present application also provide a multilayer film. The multilayer film can be prepared by any of the multilayer film preparation methods provided in the first aspect. The technical effects of the corresponding solutions in the second aspect can refer to the technical effects that can be obtained by the corresponding solutions in the first aspect, and the repetitions are not described in detail. Exemplarily, the multilayer film provided by the embodiments of the present application mainly includes a plurality of second material layers and a first material layer; wherein, a plurality of second material layers are stacked on the surface of the first material layer, and each second material layer is stacked on the surface of the first material layer. The material layer includes a second substrate, and the second substrate is composed of a ferroelectric single crystal material.

In addition to the second substrate, the second material layer may also include other thin film layers. In a possible implementation manner, each second material layer may further include a second intermediate layer provided on the surface of the second substrate.

In another possible implementation manner, each second material layer may further include a second intermediate layer and a second bonding layer; wherein the second intermediate layer is disposed on the surface of the second substrate, and the second bonding layer It is arranged on the surface of the second intermediate layer away from the second substrate.

In the case that the second material layer may include other thin film layers in addition to the second substrate, the first surfaces of the plurality of second material layers are all disposed toward the first material layer, wherein the first material layer of the second material layer The surface can be understood as the surface of the second material layer away from the second substrate.

Similar to the second material layer, the first material layer may include other thin film layers in addition to the first substrate. In a possible implementation manner, the first material layer may include a first substrate and a first intermediate layer provided on the surface of the first substrate.

In another possible implementation manner, the first material layer may include a first substrate, a first intermediate layer, and a first bonding layer; wherein the first intermediate layer is disposed on the surface of the first substrate, and the first bond The laminated layer is arranged on the surface of the first intermediate layer away from the first substrate.

In the case where the first material layer may include other thin film layers in addition to the first substrate, a plurality of second material layers may be stacked on the surface of the first material layer away from the first substrate.

In order to adapt to different application scenarios, in a possible implementation manner, a third intermediate layer may also be provided between adjacent second material layers.

In another possible implementation manner, a third intermediate layer and a third bonding layer may also be stacked between adjacent second material layers. Wherein, the third intermediate layer is arranged close to the first substrate, and the third bonding layer is arranged away from the first substrate.

Exemplarily, the thickness of the second substrate in the multilayer film may be 10-100 μm.

These and other aspects of the application will be more concise and understandable in the description of the following embodiments.

Description of the drawings

FIG. 1 is a schematic flow chart of a method for preparing a multilayer film according to an embodiment of the application;

2 is a schematic diagram of a multilayer film structure provided by an embodiment of the application;

3a-3e are schematic diagrams of a first material layer structure provided by an embodiment of the application;

4a-4e are schematic diagrams of a second material layer structure provided by an embodiment of the application;

5 is one of the schematic diagrams of the intermediate structure in the preparation process of a multilayer film provided by an embodiment of the application;

FIG. 6 is a schematic diagram of a process of arranging a second material layer on the surface of the first material layer according to an embodiment of the application;

FIG. 7 is the second schematic diagram of the intermediate structure in the preparation process of a multilayer film according to an embodiment of the application;

FIG. 8 is the third schematic diagram of the intermediate structure in the preparation process of a multilayer film provided by an embodiment of the application.

Detailed ways

With the development of material processing technology and technology, the application of thin film materials in devices has become increasingly widespread. In particular, multilayer films are used in various semiconductor devices. For example, semiconductor devices such as lasers, memories, sensors, and capacitors are mostly composed of multilayer films.

Generally speaking, a multilayer film is composed of a plurality of film layers laminated, and the film layers of different layers can be composed of the same or different materials. At present, multi-layer films are mainly prepared through growth or deposition processes to prepare multiple film layers layer by layer on a substrate to obtain a multi-layer film. For example, magnetron sputtering, chemical vapor deposition, atomic layer growth, molecular beam epitaxy, etc., can all be used to prepare multilayer films. Through these growth or deposition processes, thin film materials of a wide variety of material types can be prepared, and the growth film surface is flat, the structure is better, and the cost is low, which can meet many application scenarios.

However, most of the ferroelectric single crystal materials cannot be prepared by growth or deposition processes in the current multilayer film preparation process, which limits the application of these materials in multilayer films. It can be seen that there are still some shortcomings in the scope of application of the growth or deposition process. At present, there is an urgent need for a multilayer thin film preparation method (process) that can complement the growth or deposition process so that ferroelectric single crystal materials can be used in multiple layers. The film is applied.

In view of this, the embodiments of the present application provide a method for preparing a multilayer film. The method is based on a second substrate made of a ferroelectric single crystal material without a growth or deposition process. In the preparation of multiple thin film layers composed of ferroelectric single crystal materials.

In order to make the purpose, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operation method in the method embodiment can also be applied to the device embodiment or the system embodiment. It should be noted that in the description of this application, "at least one" refers to one or more, and multiple refers to two or more. In view of this, in the embodiments of the present invention, “a plurality of” may also be understood as “at least two”. "And/or" describes the association relationship of the associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. In addition, the character "/", unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship. In addition, it should be understood that in the description of this application, words such as “first” and “second” are only used for the purpose of distinguishing description, and cannot be understood as indicating or implying relative importance, nor can it be understood as indicating Or imply the order.

For convenience, a specific spatial relative terminology system is used in the following description, and this is not restrictive. The terms "upper" and "lower" identify directions in the drawings to which reference is made. The terms include the terms specifically mentioned above, their derivatives, and similarly introduced terms. "Above", "Above", "Above the surface", "Above", etc., are used to describe the difference between a device or feature and other devices or features as shown in the figure Spatial location relationship. It should be understood that the spatial relative terms are intended to encompass different orientations other than the orientation of the device described in the figure. For example, if the device in the drawing is turned upside down, then a device described as "above other devices or structures" or "above other devices or structures" will then be positioned as "below other devices or structures" or "on Under other devices or structures". Therefore, the exemplary term "above" can include both orientations "above" and "below". The device can also be positioned in other different ways (rotated by 90 degrees or in other orientations), and the relative description of the space used here shall be explained accordingly.

It should be pointed out that the surface of each film in the multilayer film can be understood as the surface of the film in contact with the adjacent film, or the surface perpendicular to the thickness direction, where the thickness direction can be understood as the multilayer film The direction of stacking sequentially.

Exemplarily, the method for preparing the multilayer film provided in the embodiment of the present application may be as shown in FIG. 1, and mainly includes the following steps:

S101: Prepare the first material layer.

S102: A plurality of second material layers are stacked on the surface of the first material layer, where each second material layer includes a second substrate, and the second substrate is made of a ferroelectric single crystal material.

Through the preparation method of the multilayer film shown in FIG. 1, the multilayer film as shown in FIG. 2 can be obtained. As shown in FIG. 2, the multilayer film includes a first material layer 10 and a plurality of second material layers (21 to 2N), where N is an integer greater than 1. Next, the first material layer 10 and the second material layers 21 to 2N, and the preparation process thereof will be described respectively.

The first material layer 10

In the embodiment of the present application, the first material layer 10 may include a first substrate, and the first substrate has a relatively high mechanical strength, and therefore can carry the second material layers 21 to 2N. In a possible implementation manner, the first material layer 10 may be composed of a first substrate, or it can be understood that the first substrate serves as the first material layer 10 and carries the second material layers 21 to 2N. In this case, when preparing the first material layer, the first substrate may be subjected to pretreatment such as cleaning and annealing, and then the pretreated first substrate may be used as the first material layer 10.

It should be pointed out that the embodiment of the present application does not limit the specific material of the first substrate. When preparing the first material layer, the material of the first substrate can be flexibly selected according to the application scenarios of the multilayer film. Generally speaking, the first substrate can be made of materials such as silicon and germanium.

In another possible implementation manner, other thin film layers can also be prepared on the first substrate to obtain the first material layer 10. Exemplarily, as shown in FIG. 3a, the first material layer 10 may include a first substrate 101 and a first intermediate layer 102 disposed on the surface of the first substrate 101. When preparing the first material layer 10, A first intermediate layer 102 is prepared on the surface of the first substrate 101 to obtain the first material layer 10. Specifically, the first intermediate layer 102 can be prepared on the surface of the first substrate 101 through a deposition or growth process, or the first intermediate layer 102 can be prepared on the surface of the first substrate 101 through a bonding process. The application embodiment does not restrict this.

The functions of the first intermediate layer 102 can be flexibly designed according to application scenarios. Illustratively, the first intermediate layer 102 can be a sacrificial layer, a buffer layer, a contact layer, etc., which are not listed in the embodiment of the present application. It should be pointed out that, in the embodiment of the present application, the first intermediate layer 102 may have a single-layer structure or a multi-layer structure. As shown in Figure 3b, the first intermediate layer 102 may include i first intermediate sublayers (1021 to 102i), i is an integer greater than or equal to 1, and different first intermediate sublayers may have the same or Different physical parameters such as material, thickness and crystal structure. When preparing the first intermediate layer 102, the first intermediate sublayer 1021 may be prepared layer by layer to the first intermediate sublayer 102i, so as to obtain the first intermediate layer 102.

In the embodiment of the present application, a plurality of second material layers 21 to 2N may be stacked on the surface of the first material layer 10 through a bonding process. In other words, the second material layer 21 needs to be bonded to the surface of the first material layer 10. However, some thin film materials cannot be directly applied to the bonding process. In view of this, a first bonding layer can also be prepared in the first material layer 10 to facilitate bonding of the second material layer 21.

Exemplarily, the first bonding layer 103 may include silicon dioxide, polysilicon, silicon nitride, copper, zirconium, gold-tin alloy, benzocyclobutene resin type thermosetting polymer or ultraviolet curing polymer, spin coating One or more of polymers (such as polyarylether), methyl silsesquioxane, hydrogen silsesquioxane, gaseous deposition polymer polypara-xylene-N and other materials.

In a possible implementation, as shown in FIG. 3c, the first material layer 10 may include a first substrate 101, a first intermediate layer 102 disposed on the surface of the first substrate 101, and a first intermediate layer 102 disposed on the surface of the first substrate 101. The first bonding layer 103 on the surface of 102. When preparing the first material layer 10, the first intermediate layer 102 may be prepared on the surface of the first substrate 101 first, and then the first bonding layer 103 may be prepared on the surface of the first intermediate layer 102 away from the first substrate 101. Thus, the first material layer 10 is obtained. Specifically, the first bonding layer 103 may be prepared on the surface of the first intermediate layer 102 through a deposition or growth process, or the first bonding layer 103 may be prepared on the surface of the first intermediate layer 102 through a bonding process. The embodiments of the application do not limit this.

It should be pointed out that, in the embodiment of the present application, the first bonding layer 103 may have a single-layer structure or a multi-layer structure. As shown in Figure 3d, the first bonding layer 103 may include j first bonding sublayers (1031 to 103j), j is an integer greater than or equal to 1, and different first bonding sublayers may have the same Or different physical parameters such as material, thickness and crystal structure. When preparing the first bonding layer 103, the first bonding sublayer 1031 can be prepared layer by layer to the first bonding sublayer 102j, so as to obtain the first bonding layer 103.

It can be understood that in another possible implementation manner, in the case that the first intermediate layer 102 does not need to be prepared in the first material layer 10, the first bonding layer 103 can also be prepared on the surface of the first substrate 101 to obtain The first material layer 10 is shown in Fig. 3e. The specific preparation process will not be repeated.

The second material layer 21 to 2N

Taking the second material layer 21 (other second material layers are similar) as an example, the second material layer 21 may include a second substrate, and the second substrate may be composed of a ferroelectric single crystal material. Specifically, the second substrate may be composed of an intrinsic (undoped) ferroelectric single crystal material, or it may be composed of a doped ferroelectric single crystal material, which is not limited in the embodiments of the present application. .

At present, the preparation process of the ferroelectric single crystal material wafer is relatively mature. Therefore, the second substrate in the embodiment of the present application can be obtained on the basis of the ferroelectric single crystal material wafer, that is, the embodiment of the present application The second substrate in can be understood as part or all of the ferroelectric single crystal material wafer.

Exemplarily, the ferroelectric single crystal material in the embodiments of the present application may be lithium niobate, blackened lithium niobate, doped lithium niobate, lithium tantalate, blackened lithium tantalate, doped lithium tantalate, iron Any one of bismuth oxide, barium titanate, barium strontium titanate, strontium titanate, etc., will not be listed one by one in the embodiment of the present application.

It should be pointed out that the second substrates in the different second material layers in the embodiments of the present application may be composed of the same or different ferroelectric single crystal materials, and the embodiments of the present application do not limit this.

In a possible implementation, the second material layer 21 can be composed of a second substrate, or it can be understood that the second substrate is used as the second material layer 21, that is, it is bonded on the surface of the first material layer 10.合Second substrate. In this case, when preparing the first material layer 10, after pretreatments such as cleaning and annealing are performed on the second substrate, the pretreated second substrate can be used as the second material layer 21.

In another possible implementation manner, other thin film layers can also be prepared on the second substrate to obtain the second material layer 21. Exemplarily, as shown in FIG. 4a, the second material layer 21 may include a second substrate 211 and a second intermediate layer 212 provided on the surface of the second substrate 211. When preparing the second material layer 21, A second intermediate layer 212 is prepared on the surface of the second substrate 211 to obtain the second material layer 21. Specifically, the second intermediate layer 212 may be prepared on the surface of the second substrate 211 through a deposition or growth process, or the second intermediate layer 212 may be prepared on the surface of the second substrate 211 through a bonding process. The application embodiment does not restrict this.

Similar to the first intermediate layer 102, the second intermediate layer 212 may have a single-layer structure or a multi-layer structure, as shown in FIG. 4b. The second intermediate layer 212 includes stacked second intermediate sub-layers 2121 to 212k. For specific implementation, reference may be made to the first intermediate layer 102, which will not be repeated.

Similar to the first intermediate layer 102, the second intermediate layer 212 may also include a second bonding layer. In a possible implementation, as shown in FIG. 4c, the second material layer 21 may include a second substrate 211, a second intermediate layer 212 provided on the surface of the second substrate 211, and a second intermediate layer provided on the surface of the second substrate 211. 212 on the surface of the second bonding layer 213. When preparing the second material layer 21, the second intermediate layer 212 may be prepared on the surface of the second substrate 211 first, and then the second bonding layer 213 may be prepared on the surface of the second intermediate layer 212 away from the second substrate 211. Thus, the second material layer 21 is obtained. Specifically, the second bonding layer 213 may be prepared on the surface of the second intermediate layer 212 through a deposition or growth process, or the second bonding layer 213 may be prepared on the surface of the second intermediate layer 212 through a bonding process. The embodiments of the application do not limit this.

Similar to the first bonding layer 103, the second bonding layer 213 may have a single-layer structure or a multi-layer structure. As shown in FIG. 4d, the second bonding layer 213 may include m first bonding sublayers (2131 to 213m), and m is an integer greater than or equal to 1. For specific implementation, please refer to the first bonding layer 103. This application This is not repeated in the embodiment.

In another possible implementation manner, in the case that the second intermediate layer 212 does not need to be prepared in the second material layer 21, the second bonding layer 213 can also be prepared on the surface of the second substrate 211, as shown in FIG. 4e The second material layer 21 is shown. The specific preparation process will not be repeated.

After the first material layer 10 and the second material layers 21 to 2N are obtained, S102 can be continued, and multiple second material layers are stacked on the surface of the first material layer. This process mainly includes: disposing the second material layer 21 on the surface of the first material layer 10, disposing the second material layer 22 on the surface of the second material layer 21 away from the first material layer 10, and so on, until the first material layer The second material layer 2N is arranged on the surface of the second material layer 2 (N-1) (not shown in FIG. 2) away from the first material layer 10.

Next, the second material layer 21 provided on the surface of the first material layer 10 will be further described.

Generally speaking, the second material layer 21 can be disposed on the surface of the first material layer 10 by means such as a bonding process. It should be pointed out that in the case where the first material layer 10 only includes the first substrate 101, the second material layer 21 may be provided on any surface of the first substrate 101. In the case where the first material layer 10 includes the first intermediate layer 102, as shown in FIG. 3a, the second material layer 21 may be disposed on the surface of the first intermediate layer 102 away from the first substrate 101. In the case where the first material layer 101 further includes the first bonding layer 103, as shown in FIGS. 3c and 3e, the second material layer 21 may be disposed on the first bonding layer 103 away from the first substrate 101. surface.

In the embodiment of the present application, the surface of the second material layer 21 in contact with the first material layer 10 may be referred to as the first surface of the second material layer 21. Specifically, in the case where the second material layer 21 only includes the second substrate 211, the first surface may be any surface of the second substrate 211. In the case where the second material layer 21 further includes the second intermediate layer 211, as shown in FIG. 4a, the first surface may be the surface of the second intermediate layer 211 away from the first substrate, that is, the second intermediate layer 211 It is in contact with the first material layer 10. In the case where the second material layer 21 further includes the second bonding layer 213, as shown in FIGS. 4c and 4e, the first surface may be the surface of the second bonding layer 213 away from the first substrate, that is to say , The second bonding layer 213 is in contact with the first material layer 10.

FIG. 5 exemplarily shows the intermediate structure obtained after the first material layer 10 and the second material layer 21 are fixed. As shown in FIG. 5, the first bonding layer 103 in the first material layer 10 is bonded to the second bonding layer 213 in the second material layer 21, thereby completing the first material layer 10 and the second material layer 21 Between the fixed. On the basis of the intermediate structure shown in FIG. 5, the second material layer 22 can be stacked continuously.

Next, taking FIG. 6 as an example, the process of disposing the second material layer 21 on the surface of the first material layer 10 is further exemplified to obtain the intermediate structure shown in FIG. 7. As shown in Figure 6, it mainly includes the following steps:

S601: Perform preprocessing on the first substrate 101. Such as cleaning, annealing, etc., the embodiments of the present application do not limit this.

S602: sequentially preparing first intermediate sublayers 1021 to 102i on the surface of the first substrate 101 to obtain the first intermediate layer 102.

S603: Continue to sequentially prepare the first bonding sublayers 1031 to 103j on the surface of the first intermediate sublayer 102i to obtain the first bonding layer 103.

S604: Perform preprocessing on the second substrate 211. Such as cleaning, annealing, etc., the embodiments of the present application do not limit this.

S605: The second intermediate sublayers 2121 to 212k are sequentially prepared on the surface of the second substrate 211 to obtain the second intermediate layer 212.

S606: Continue to sequentially prepare the second bonding sublayers 2131 to 213m on the surface of the second intermediate sublayer 202k to obtain the second bonding layer 213.

It should be pointed out that the embodiment of the present application does not strictly limit the sequence of preparing the first material layer 10 and the second material layer 21, that is to say, S601 to S603 can be performed first, and then S604 to S606; or Execute S604 to S606, and then execute S601 to S603; it is also possible to execute the process of S601 to S603 and the process of S604 to S606 in parallel.

S607: Perform planarization treatment on the surface of the first bonding sublayer 103j away from the first substrate 101, and perform planarization treatment on the surface of the second bonding sublayer 213m away from the second substrate 211. The planarization process can eliminate the surface defects of the first substrate 101 and the second substrate 211, which is beneficial to improve the subsequent bonding effect.

S608: Bonding the first bonding sublayer 103j away from the surface of the first substrate 101 and the surface of the second bonding sublayer 213m away from the second substrate 211, thereby obtaining the intermediate structure shown in FIG. 7.

In a possible implementation manner, S609: thinning the second substrate 211 can also be continued.

S610: Perform a planarization treatment on the thinned surface of the second substrate 211.

After the intermediate structure shown in FIG. 5 or FIG. 7 is obtained, the second material layer 22 can be continuously provided. Specifically, the first surface of the second material layer 22 may be continuously provided on the surface of the second substrate 211 away from the first substrate 101. The first surface of the second material layer 22 is similar to the second material layer 21, which will not be repeated here. In other words, the first surfaces of the second material layers 21 to 2N are all disposed toward the first material layer 10.

In a possible implementation manner, before the second material layer 22 is provided, the second substrate 211 in the second material layer 21 may be thinned first, so that the thickness of the second substrate can reach the target thickness. Generally, the second substrate 211 can be thinned to a thickness range of 10-100 μm.

After the thinning, the surface of the second material layer 21 away from the first material layer 10 can be flattened, and the second material layer 22 can be continuously provided on the surface after the flattening treatment to reduce the defects of the multilayer film and improve The quality of the multilayer film.

It can be understood that a third intermediate layer may be spaced between the second material layer 22 and the second material layer 21 to optimize the structure of the multilayer film or to realize the specific function of the multilayer film. In other words, the third intermediate layer may be prepared on the surface of the second substrate 211 away from the first substrate 101, and then the second material layer 22 may be disposed on the surface of the third intermediate layer away from the second substrate 211.

In a possible implementation manner, as shown in FIG. 8, a third material layer 31 is provided on the surface of the second material layer 21. The third material layer 31 may only include the third intermediate layer 311 or only the third bonding layer 312. It can be understood that the third material layer 31 may also include both the third intermediate layer 311 and the third bonding layer 312. In this case, when the second material layer 22 is provided on the surface of the second material layer 21, the A third intermediate layer 311 is prepared on the surface of the second material layer 21, and then a third bonding layer 312 is prepared on the surface of the third intermediate layer away from the second material layer 21, and then the third bonding layer is away from the second material layer 21 On the surface, a second material layer 22 is provided.

It can be understood that the third intermediate layer 311 may have a single-layer structure or a multi-layer structure. For specific implementation, refer to the first intermediate layer 102, which will not be described in detail. The third bonding layer 312 may be a single-layer structure or a multi-layer structure. For the specific implementation, please refer to the first bonding layer 103, which will not be repeated here. The setting process of the second material layer 23 to 2N can refer to the second material layer 22, which will not be repeated here.

The use of the multilayer film preparation method provided in the embodiments of the present application is beneficial to expand the applicable scope of the multilayer film preparation process. Specifically, in the embodiment of the present application, a plurality of second material layers are laminated on the surface of the first material layer, and each second material layer includes a second substrate. Therefore, the obtained multilayer film may include multiple layers made of iron. The second substrate is made of electric single crystal material, and the second substrate is made of ferroelectric single crystal material, which in turn realizes the preparation of multiple thin film layers made of ferroelectric single crystal material in a multilayer film .

Obviously, those skilled in the art can make various changes and modifications to this application without departing from the protection scope of this application. In this way, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, then this application is also intended to include these modifications and variations.

Claims

A method for preparing a multilayer film, which is characterized in that it comprises:

Preparing the first material layer;

A plurality of second material layers are stacked on the surface of the first material layer, wherein each second material layer includes a second substrate, and the second substrate is made of a ferroelectric single crystal material.
The method according to claim 1, characterized in that, before stacking a plurality of second material layers on the surface of the first material layer, the method further comprises:

For each second material layer, a second intermediate layer is prepared on the surface of the second substrate to obtain the second material layer.
The method according to claim 1, characterized in that, before stacking a plurality of second material layers on the surface of the first material layer, the method further comprises:

For each second material layer, a second intermediate layer is prepared on the surface of the second substrate;

A second bonding layer is prepared on the surface of the second intermediate layer away from the second substrate to obtain the second material layer.
The method according to claim 2 or 3, wherein the stacking and disposing of the plurality of second material layers on the surface of the first material layer comprises:

The plurality of second material layers are stacked on the surface of the first material layer, wherein the first surfaces of the plurality of second material layers are all disposed toward the first material layer, and the second material layer The first surface of is the surface of the second material layer away from the second substrate.
The method according to any one of claims 1 to 4, wherein preparing the first material layer comprises:

A first intermediate layer is prepared on the surface of the first substrate to obtain the first material layer.
The method according to any one of claims 1 to 4, wherein preparing the first material layer comprises:

Preparing a first intermediate layer on the surface of the first substrate;

A first bonding layer is prepared on the surface of the first intermediate layer away from the first substrate to obtain the first material layer.
The method according to claim 5 or 6, wherein the stacking and disposing the plurality of second material layers on the surface of the first material layer comprises:

The plurality of second material layers are stacked on the surface of the first material layer away from the first substrate.
The method according to any one of claims 1 to 7, wherein the stacking and disposing of the plurality of second material layers on the surface of the first material layer comprises:

Disposing a second material layer on the surface of the first material layer, and preparing a third intermediate layer on the surface of the already disposed second material layer;

Another second material layer is provided on the surface of the third intermediate layer away from the second material layer that has been provided, until the multiple second material layers are completed.
The method according to any one of claims 1 to 7, wherein the stacking and disposing of the plurality of second material layers on the surface of the first material layer comprises:

Disposing a second material layer on the surface of the first material layer;

Preparing a third intermediate layer on the surface of the second material layer that has been set;

Preparing a third bonding layer on the surface of the third intermediate layer away from the second material layer;

On the surface of the third bonding layer away from the second material layer that has been arranged, another second material layer is arranged until the arrangement of the plurality of second material layers is completed.
The method according to claim 8 or 9, characterized in that, before preparing the third intermediate layer on the surface of the second material layer that has been set, the method further comprises:

Performing thinning at the position of the second surface of the second material layer that has been provided, so that the second substrate in the second material layer that has been provided reaches a target thickness;

Planarizing the second surface of the second material layer that has been set;

The second surface of the second material layer is the surface where the second substrate is located in the second material layer.
The method according to any one of claims 1 to 10, wherein the ferroelectric single crystal material comprises: lithium niobate, blackened lithium niobate, doped lithium niobate, lithium tantalate, blackened Lithium tantalate, doped lithium tantalate, bismuth ferrite, barium titanate, barium strontium titanate, or strontium titanate.
A multilayer film, characterized by comprising: a plurality of second material layers and a first material layer;

The plurality of second material layers are stacked on the surface of the first material layer;

Wherein, each of the second material layers includes a second substrate, and the second substrate is composed of a ferroelectric single crystal material.
The multilayer film according to claim 12, wherein each of the second material layers further comprises a second intermediate layer provided on the surface of the second substrate.
The multilayer film according to claim 12, wherein each of the second material layers further comprises a second intermediate layer and a second bonding layer;

Wherein, the second intermediate layer is arranged on the surface of the second substrate, and the second bonding layer is arranged on the surface of the second intermediate layer away from the second substrate.
The multilayer film according to any one of claims 12 to 14, wherein the first surfaces of the plurality of second material layers are all disposed toward the first material layer, and the second material layer The first surface is the surface of the second material layer away from the second substrate.
The multilayer film according to any one of claims 12 to 15, wherein the first material layer comprises a first substrate and a first intermediate layer provided on the surface of the first substrate.
The multilayer film according to any one of claims 12 to 15, wherein the first material layer comprises a first substrate, a first intermediate layer and a first bonding layer;

Wherein, the first intermediate layer is arranged on the surface of the first substrate, and the first bonding layer is arranged on the surface of the first intermediate layer away from the first substrate.
The multilayer film according to claim 16 or 17, wherein the plurality of second material layers are stacked on the surface of the first material layer away from the first substrate.
The multilayer film according to any one of claims 12 to 18, wherein a third intermediate layer is further provided between adjacent second material layers.
The multilayer film according to any one of claims 12 to 18, wherein a third intermediate layer and a third bonding layer are laminated between adjacent second material layers.
The multilayer film according to any one of claims 13 to 20, wherein the thickness of the second substrate is 10-100 μm.
The multilayer film according to any one of claims 12 to 21, wherein the ferroelectric single crystal material comprises: lithium niobate, blackened lithium niobate, doped lithium niobate, lithium tantalate, Blackened lithium tantalate, doped lithium tantalate, bismuth ferrite, barium titanate, barium strontium titanate, or strontium titanate.