Composite structure substrate, preparation method thereof and electronic device

Abstract

The invention discloses a composite structure substrate and a preparation method thereof, and an electronic device, the composite structure substrate sequentially comprises a supporting substrate, a bonding structure layer and a functional film layer, the functional film layer is obtained by performing surface treatment on a first functional layer and a second functional layer, a damage layer is formed on a first surface, far away from the supporting substrate, of the first functional layer; wherein the surface treatment comprises the following steps of: performing etching treatment on the first surface in the first functional layer to obtain the second functional layer; the etching thickness of the etching treatment is greater than the thickness of the damaged layer; and performing chemical mechanical polishing treatment on the second functional layer, removing the amorphous layer on the surface of the second functional layer, and performing thinning treatment to obtain the functional thin film layer. According to the invention, the surface treatment is converted into the functional thin film layer twice, so that better film thickness uniformity can be achieved, and the performance of the device can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor electronic technology, and in particular to a composite structure substrate and a preparation method thereof, and an electronic device. Background Art

[0002] In the semiconductor field, heterogeneous integration of multiple materials is an important path to improve chip performance and integration. By preparing materials with piezoelectric, ferroelectric, optoelectronic, pyroelectric, nonlinear and other properties into thin film structures and integrating them with different materials, the advantages of different materials can be fully utilized to improve chip performance. Generally speaking, the composite structure substrate of heterogeneous integration contains a functional film layer, the thickness of which is usually at the nanoscale, and the thickness of the film has an important influence on the performance of the device on its surface. For example, for acoustic devices, the thickness of the functional film layer will affect the resonant frequency of the acoustic device, and then affect parameters such as the electromechanical coupling coefficient of the device. For another example, for optical devices, the thickness of the functional film will affect the effective refractive index of the waveguide and affect the performance of the optical device. Therefore, maintaining good uniformity of the film thickness of the functional film layer in the composite structure substrate helps to improve the performance of the prepared device and the stability of the device performance, which is crucial in the large-scale production of composite structure substrates.

[0003] In the related technology, the chemical mechanical polishing (CMP) process can be used to control the thickness of the film. However, as the amount of functional film removed increases, the non-uniformity of the film thickness will gradually worsen, especially the thickness difference of the functional film layer between different areas on the composite structure substrate becomes larger and larger, which in turn affects the performance of the device. Summary of the invention

[0004] In view of at least one technical problem in the prior art, the purpose of the present application is to provide a composite structure substrate and a preparation method thereof, and an electronic device.

[0005] In order to solve the above technical problems, on the one hand, the present application provides a composite structure substrate, comprising:

[0006] a supporting substrate;

[0007] a bonding structure layer located on the supporting substrate;

[0008] a functional film layer located on the bonding structure layer, wherein the functional film layer is obtained by surface treating a first functional layer and a second functional layer, a damaged layer is formed on a first surface of the first functional layer away from the supporting substrate, and the second functional layer is converted by surface treating the first functional layer;

[0009] The surface treatment of the first functional layer includes: etching the first surface of the first functional layer to obtain the second functional layer; the etching thickness of the etching process is greater than the thickness of the damaged layer;

[0010] The surface treatment of the second functional layer includes: performing chemical mechanical polishing on the second functional layer to remove the amorphous layer on the surface of the second functional layer, and thinning the remaining second functional layer to obtain the functional thin film layer; the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10~1.20.

[0011] In some embodiments, the etching process is implemented by at least one of the following two methods:

[0012] When the initial thickness uniformity of the first functional layer is 1-10 nm, the first functional layer is subjected to a first etching process to remove a material of a first preset thickness, thereby obtaining the second functional layer; the thickness of the second functional layer is the difference between the thickness of the first functional layer and the first preset thickness;

[0013] When the initial thickness uniformity of the first functional layer is 10 to 100 nm, the second functional layer of a second preset thickness is obtained by performing a second etching treatment on the first functional layer; the material removal thickness of the second etching treatment is the difference between the thickness of the first functional layer and the second functional layer; wherein the second preset thickness includes setting the edge thickness of the second functional layer to be smaller than the center thickness or the thickness of one half of the second functional layer to be smaller than the thickness of the opposite half.

[0014] In some embodiments, the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching process is 1:0.20-0.80;

[0015] The thickness uniformity of the second functional layer is 1 to 10 nm;

[0016] The surface roughness of the functional film layer is 0.05-0.5 nm.

[0017] In some embodiments, the chemical mechanical polishing of the second functional layer to remove the amorphous layer on the surface of the second functional layer and thinning the remaining second functional layer to obtain the functional thin film layer includes:

[0018] The second functional layer is subjected to chemical mechanical polishing to remove the surface residual layer and the amorphous layer on the surface of the second functional layer, and the remaining second functional layer is thinned to obtain the functional thin film layer of the second functional layer; wherein the surface roughness of the surface residual layer is between 0.5 and 20 nm.

[0019] In some embodiments, the composite structure substrate satisfies at least one of the following:

[0020] The composite structure substrate further comprises a carrier trapping layer, which is arranged between the support substrate and the bonding structure layer and is used to trap free carriers in the support substrate;

[0021] The material of the functional thin film layer is at least one of single crystal lithium niobate, single crystal lithium tantalate, quartz, aluminum nitride, gallium nitride, gallium oxide, calcium fluoride, silicon, sapphire, silicon carbide, and diamond;

[0022] The material of the bonding structure layer is silicon oxide;

[0023] The material of the carrier trapping layer is polycrystalline silicon, amorphous silicon or porous silicon;

[0024] The support substrate is at least one of silicon, silicon oxide, polysilicon, silicon on insulator, sapphire, silicon carbide, silicon carbide on insulator, quartz, aluminum nitride, gallium nitride, and diamond.

[0025] On the other hand, the present application also provides a method for preparing a composite structure substrate, comprising:

[0026] Providing a supporting substrate, and forming an auxiliary bonding layer on a surface of the supporting substrate;

[0027] Providing a functional substrate having an initial thin film functional layer formed thereon, and performing ion implantation on a surface of the functional substrate away from the initial thin film functional layer;

[0028] Bonding the functional substrate and the supporting substrate via the auxiliary bonding layer to obtain a bonding structure layer;

[0029] Annealing the bonding structure layer once and peeling it off from the damaged layer formed by ion implantation to form a first functional layer on the bonding structure layer;

[0030] The first functional layer is subjected to secondary annealing, and the first functional layer and the second functional layer are subjected to surface treatment to form a thin film functional layer, so as to obtain a composite structure substrate; the second functional layer is formed by converting the first functional layer through surface treatment; wherein the surface treatment includes etching the first functional layer and chemical mechanical polishing the second functional layer, and the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10~1.20.

[0031] In some embodiments, the surface treatment process satisfies at least one of the following:

[0032] The etching method of the etching treatment includes at least one of physical etching, chemical etching, and physical and chemical etching;

[0033] The polishing back pressure of the chemical mechanical polishing is in the range of 0.5-5.5 lbf / square inch, and the thickness of the material removed by the chemical mechanical polishing is in the range of 20-120 nm.

[0034] In some embodiments, before performing the etching process or the chemical mechanical polishing process, the method further includes:

[0035] The step of chamfering the edge of the first functional layer or the second functional layer, wherein the width of the chamfer is 1 to 5 mm, the depth of the chamfer is 10 to 100 um, and the shape of the chamfer is an R-shaped chamfer.

[0036] In some embodiments, the method satisfies at least one of the following:

[0037] The type of implanted ions is at least one of hydrogen ions, helium ions or argon ions, the implantation energy is between 20 KeV and 300 KeV, and the implantation dose is 1E14 ions / cm 2 to 1E17 ions / cm 2 ;

[0038] The bonding structure layer is annealed at a temperature of 100° C. to 400° C., and the atmosphere of the heat treatment is at least one of an inert gas, nitrogen, oxygen, and a vacuum environment;

[0039] The temperature of the secondary annealing of the first functional layer is 200° C. to 1200° C., and the atmosphere of the heat treatment is at least one of an inert gas, oxygen, nitrogen, and a vacuum environment.

[0040] On the other hand, the present application also provides an electronic device, comprising:

[0041] Any of the above-mentioned composite structure substrates, or a composite structure substrate prepared by any of the above-mentioned methods;

[0042] The surface electrode is arranged on the surface of the thin film functional layer in the composite structure substrate.

[0043] The composite structure substrate and its preparation method and electronic device of the present application have at least the following characteristics:

[0044] Beneficial effects:

[0045] The composite structure substrate provided by the embodiment of the present application includes a supporting substrate; a bonding structure layer located on the supporting substrate; a functional thin film layer located on the bonding structure layer, wherein the functional thin film layer is obtained by surface treating a first functional layer and a second functional layer, a damaged layer is formed on a first surface of the first functional layer away from the supporting substrate, and the second functional layer is formed by surface treating the first functional layer; wherein the surface treating the first functional layer includes: etching the first surface in the first functional layer to obtain the second functional layer; the etching thickness of the etching treatment is greater than the thickness of the damaged layer; the surface treating the second functional layer includes: chemically mechanically polishing the second functional layer to remove the amorphous layer on the surface of the second functional layer, and thinning the remaining second functional layer to obtain the functional thin film layer; the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10~1.20.

[0046] In this way, by utilizing the characteristics that the damaged layer on the surface of the functional thin film layer is removed faster and more easily than the single crystal layer located below the damaged layer, the damaged layer on the surface of the first functional layer in the composite structure substrate and part of the first functional layer material are quantitatively removed by surface etching, or the first functional layer is removed to the target thickness distribution, thereby effectively reducing the thickness of the second functional layer that needs to be removed by chemical mechanical polishing. That is, the first functional layer and the second functional layer in the composite structure substrate are surface treated respectively, and the two conversions of the surface treatment into the functional thin film layer are beneficial to achieving better film thickness uniformity and improving device performance, and is suitable for large-scale production of composite structure substrates, thereby reducing processing time, improving processing yield, and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 is a schematic diagram of a preparation process of a composite structure substrate provided in an embodiment of the present application;

[0049] Figure 2 This is a surface electron microscope image of the second functional layer prepared according to the embodiment of the present application;

[0050] Figure 3 is a schematic structural diagram of another composite structure substrate provided in an embodiment of the present application;

[0051] Figure 4 These are AFM and SEM images of the surface residual layer after ion beam etching provided in the embodiments of the present application;

[0052] Figure 5 is a film thickness distribution diagram of the functional thin film layer prepared according to the embodiment of the present application;

[0053] Figure 6 This is an AFM image of the functional thin film layer prepared as provided in the examples of the present application. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0055] The "one embodiment" or "embodiment" referred to below refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. In the description of the present invention, unless otherwise clearly specified and limited, the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0056] It should be understood that when describing the structure of a component, when a layer or a region is referred to as being located "on" or "above" another layer or another region, it may mean that it is directly located on the other layer or another region, or that other layers or regions are included between it and the other layer or another region. Moreover, if the component is turned over, the layer or a region will be located "below" or "beneath" another layer or another region.

[0057] The heterogeneously integrated composite structure substrate contains a functional film layer, the thickness of which is usually at the nanoscale. The thickness of the film has an important influence on the performance of the devices on its surface. For example, for acoustic devices, the thickness of the functional film layer will affect the resonant frequency of the acoustic device, and then affect the parameters such as the electromechanical coupling coefficient of the device. For another example, for optical devices, the thickness of the functional film will affect the effective refractive index of the waveguide and affect the performance of the optical device. Therefore, maintaining good uniformity of the film thickness of the functional film layer in the composite structure substrate is crucial in the large-scale production of composite structure substrates, which helps to improve the performance of the prepared device and the stability of the device performance.

[0058] In the related technology, the chemical mechanical polishing (CMP) process can be used to control the thickness of the film. However, as the amount of functional film removed increases, the non-uniformity of the film thickness will gradually worsen, especially the thickness difference of the functional film layer between different areas on the composite structure substrate becomes larger and larger, which in turn affects the performance of the device.

[0059] In order to solve the above technical problems, the present invention proposes a composite structure substrate and a preparation method thereof, an electronic device, and a composite structure substrate.

[0060] like Figure 1 and Figure 2 As shown, a composite structure substrate provided in an embodiment of the present application includes, from bottom to top, a supporting substrate 10, a bonding structure layer 20 and a functional film layer 33. The bonding structure layer 20 is located between the supporting substrate 10 and the functional film layer 33, and plays a role of bonding and isolation. The functional film layer is a thin layer with functional characteristics.

[0061] The functional film layer 33 is obtained by surface treating the first functional layer 31 and the second functional layer 32. A damaged layer 311 is formed on the first surface of the first functional layer 31 away from the support substrate. Optionally, the damaged layer can be formed by, for example, ion implantation. The second functional layer is formed by surface treating the first functional layer.

[0062] The surface treatment of the first functional layer includes: etching the first surface of the first functional layer to obtain the second functional layer; the etching thickness of the etching process is greater than the thickness of the damaged layer, and the thickness uniformity of the second functional layer is within a first range. The first range can be obtained by uniformly trimming the film thickness of the first functional layer after the etching process.

[0063] The surface treatment of the second functional layer 32 includes: performing chemical mechanical polishing on the second functional layer to remove the amorphous layer 321 on the surface of the second functional layer, and thinning the remaining second functional layer 322 to obtain the functional thin film layer; the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10 to 1.20. Preferably, the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.20 to 0.80.

[0064] The surface roughness of the functional thin film layer is in the second range. Optionally, the thickness uniformity of the second functional layer is 1 to 10 nm, for example, including but not limited to: 1.5 nm, 3 nm, 5 nm, 6 nm, 8 nm, 9.2 nm, etc. The surface roughness of the functional thin film layer is 0.05 to 0.5 nm, for example, including but not limited to: 0.06 nm, 0.08 nm, 0.1 nm, 0.2 nm, 0.3 nm, 0.4 nm, 0.45 nm, etc.

[0065] Optionally, during the etching process, the etching thickness is greater than the thickness of the damaged layer. Exemplarily, the etching removal thickness may be 10 to 80 nm, for example, including but not limited to: 15 nm, 20 nm, 35 nm, 40 nm, 56 nm, 62 nm, 70 nm, etc. The thickness of the damaged layer depends on the implantation depth or the grinding thickness.

[0066] In some embodiments, the etching process is implemented by at least one of the following two methods:

[0067] When the initial thickness uniformity of the first functional layer is 1-10 nm, the first functional layer is subjected to a first etching process to remove a first preset thickness of material to obtain the second functional layer; the thickness of the second functional layer is the difference between the thickness of the first functional layer and the first preset thickness. The first preset thickness is a constant value. By removing the material of the first functional layer of the first preset thickness, fast, large-scale, high-uniformity processing can be achieved.

[0068] When the initial thickness uniformity of the first functional layer is 10 to 100 nm, the second functional layer of a second preset thickness is obtained by performing a second etching treatment on the first functional layer. The material removal thickness of the second etching treatment is the difference between the thickness of the first functional layer and the thickness of the second functional layer. Optionally, the second preset thickness may not be a fixed value, but may be a range. Exemplarily, the second preset thickness includes setting the edge thickness of the second functional layer to be less than the center thickness. Another exemplary embodiment, the second preset thickness includes the thickness of one half of the second functional layer being less than the thickness of the opposite half, for example, the thickness of the left half is less than the thickness of the right half, etc. The second preset thickness can determine the preset value according to actual needs.

[0069] In some embodiments, the chemical mechanical polishing of the second functional layer to remove the amorphous layer on the surface of the second functional layer and thinning the remaining second functional layer to obtain the functional thin film layer includes:

[0070] The second functional layer is subjected to chemical mechanical polishing to remove the surface residual layer and the amorphous layer on the surface of the second functional layer, and the remaining second functional layer is subjected to thinning to obtain the functional film layer and the second functional layer; wherein the surface roughness of the surface residual layer is 0.5 to 20 nm. The surface residual layer and the amorphous layer are located on the surface of the second functional layer away from the bonding structure layer.

[0071] In some embodiments, the etching method of the etching process includes at least one of physical etching (such as ion beam etching), chemical etching (such as plasma etching) or physical and chemical etching (such as reactive ion etching).

[0072] In some embodiments, before performing the etching process or the chemical mechanical polishing process, the following operations are further performed:

[0073] The step of chamfering the edge of the first functional layer or the second functional layer, wherein the width of the chamfer is 1 to 5 mm, the depth of the chamfer is 10 to 100 um, and the shape of the chamfer is an R-shaped chamfer.

[0074] In some embodiments, the polishing back pressure of the chemical mechanical polishing is in a range of 0.5-5.5 psi, and the thickness of the material removed by the chemical mechanical polishing is in a range of 20-120 nm.

[0075] In some embodiments, Figure 3 As shown, the composite structure substrate further includes a carrier trapping layer 40, which is disposed between the support substrate and the bonding structure layer and is used to trap free carriers in the support substrate.

[0076] Optionally, the material of the functional thin film layer is at least one of single crystal lithium niobate, single crystal lithium tantalate, quartz, aluminum nitride, gallium nitride, gallium oxide, calcium fluoride, silicon, sapphire, silicon carbide, and diamond.

[0077] Optionally, the bonding structure layer is made of oxide or carbide, such as silicon oxide.

[0078] Optionally, the carrier trapping layer is made of polycrystalline silicon, amorphous silicon or porous silicon.

[0079] Optionally, the support substrate is at least one of silicon, silicon oxide, polysilicon, silicon on insulator, sapphire, silicon carbide, silicon carbide on insulator (SOI), quartz, aluminum nitride, gallium nitride, and diamond.

[0080] The above-mentioned embodiments utilize the characteristics that the damaged layer on the surface of the functional thin film layer can be removed faster and more easily than the single crystal layer located below the damaged layer, and the damaged layer on the surface of the first functional layer in the composite structure substrate and part of the first functional layer material are quantitatively removed by surface etching, or the first functional layer is removed to the target thickness distribution, thereby effectively reducing the thickness of the second functional layer that needs to be removed by chemical mechanical polishing, that is, the first functional layer and the second functional layer in the composite structure substrate are surface treated respectively, and the two conversions of the surface treatment into the functional thin film layer are beneficial to achieving better film thickness uniformity and improving device performance, and are suitable for large-scale production of composite structure substrates, thereby reducing processing time, improving processing yield, and saving costs.

[0081] On the other hand, continuing Figure 1 As shown, the present application also provides a method for preparing a composite structure substrate, comprising:

[0082] Providing a supporting substrate, and forming an auxiliary bonding layer on a surface of the supporting substrate;

[0083] Providing a functional substrate having an initial thin film functional layer formed thereon, and performing ion implantation on a surface of the functional substrate away from the initial thin film functional layer;

[0084] Bonding the functional substrate and the supporting substrate via the auxiliary bonding layer to obtain a bonding structure layer;

[0085] Annealing the bonding structure layer once and peeling it off from the damaged layer formed by ion implantation to form a first functional layer on the bonding structure layer;

[0086] The first functional layer is subjected to secondary annealing, and the first functional layer and the second functional layer are subjected to surface treatment to form a thin film functional layer, so as to obtain a composite structure substrate; the second functional layer is formed by converting the first functional layer through surface treatment; wherein the surface treatment includes etching the first functional layer and chemical mechanical polishing the second functional layer, and the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10-1.20. Preferably, the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.20-0.80.

[0087] Optionally, the etching method of the etching process includes at least one of physical etching, chemical etching, and physical and chemical etching.

[0088] Optionally, the polishing back pressure of the chemical mechanical polishing is in the range of 0.5-5.5 psi, and the thickness of the material removed by the chemical mechanical polishing is in the range of 20-120 nm.

[0089] It should be noted that the specific processes of the etching treatment and the chemical mechanical polishing treatment can be found in the above embodiments and will not be described in detail here.

[0090] In some embodiments, before performing the etching process or the chemical mechanical polishing process, the method further includes:

[0091] The step of chamfering the edge of the first functional layer or the second functional layer, wherein the width of the chamfer is 1 to 5 mm, the depth of the chamfer is 10 to 100 um, and the shape of the chamfer is an R-shaped chamfer.

[0092] Optionally, the type of implanted ions is at least one of hydrogen ions, helium ions or argon ions, the implantation energy is between 20 KeV and 300 KeV, and the implantation dose is 1E14 ions / cm 2 to 1E17ions / cm 2 .

[0093] Optionally, the bonding structure layer is annealed at a temperature of 100° C. to 400° C., and the atmosphere of the heat treatment is at least one of an inert gas, nitrogen, oxygen, and a vacuum environment.

[0094] Optionally, the temperature of the secondary annealing of the first functional layer is 200° C. to 1200° C., and the atmosphere of the heat treatment is at least one of an inert gas, oxygen, nitrogen, and a vacuum environment.

[0095] Generally, the functional thin film layer is prepared by ion beam stripping. The prepared functional thin film layer usually needs to be flattened with a large amount of surface removal to remove the damaged layer formed by ion implantation and thin the functional thin film layer to the target thickness. If a single chemical mechanical polishing process is used, the surface damaged layer will be removed quickly during the polishing process, which will affect the subsequent uniformity control, especially the increasing thickness difference of the functional thin film layer between different regions on the composite structure substrate, which will affect the performance of the device.

[0096] The present application utilizes the characteristics that the damaged layer on the surface of the functional thin film layer is removed faster and more easily than the single crystal layer located below the damaged layer. The damaged layer on the surface of the first functional layer in the composite structure substrate and part of the first functional layer material are quantitatively removed by surface etching, or the first functional layer is removed to the target thickness distribution, thereby effectively reducing the thickness of the second functional layer that needs to be removed by chemical mechanical polishing. That is, the first functional layer and the second functional layer in the composite structure substrate are surface treated separately, and the two conversions of the surface treatment into the functional thin film layer are beneficial to achieving better film thickness uniformity and improving device performance. The application is suitable for large-scale production of composite structure substrates, thereby reducing processing time, improving processing yield, and saving costs.

[0097] It should be noted that the specific details and beneficial effects in the above-mentioned preparation method embodiment of the composite structure substrate can be referred to the above-mentioned composite structure substrate embodiment, and the details and beneficial effects not expanded in the above-mentioned structure embodiment can be referred to the above-mentioned method embodiment, which will not be repeated here.

[0098] In order to demonstrate that the present application obtains a functional thin film layer through a surface flattening treatment of secondary conversion, the following description is made by taking a single crystal lithium tantalate material as an example of a functional thin film layer:

[0099] Perform etching: use etching gas (Ar, nitrogen trifluoride NF3 and N2 mixed in a ratio of 0.2-0.8:0.15-0.25:1), apply voltage of 60-90KeV, process chamber vacuum degree of 10^-5-10^-6, etching depth of 40nm, and film uniformity after etching of about 2nm. Figure 4 The AFM and SEM images of the residual layer on the surface after ion beam etching are shown in Figure 1. The roughness of the surface obtained by etching is Rq: 15.9nm; Ra: 11.2nm.

[0100] Perform chemical mechanical polishing: Use chemical mechanical planarization to globally planarize the functional film layer and reduce the surface roughness. The main polishing pressure is 3-5 pounds per square inch. Add 4 auxiliary polishing pressures, which are 0.5-0.7 pounds per square inch, 0.4-0.6 pounds per square inch, 0.2-0.3 pounds per square inch, and 0.2-0.3 pounds per square inch greater than the main polishing pressure from the edge to the center of the functional film layer. The polishing removal is 70nm. Figure 5 The functional thin film layer thickness distribution diagram and Figure 6 As shown in the AFM image, the final film thickness uniformity of the prepared functional thin film layer is about 6.308nm, and the surface roughness is about 0.195nm.

[0101] The present application also provides an electronic device, comprising:

[0102] Any of the above-mentioned composite structure substrates, or a composite structure substrate prepared by any of the above-mentioned methods;

[0103] The surface electrode is arranged on the surface of the thin film functional layer in the composite structure substrate.

[0104] Optionally, the electronic device may include but is not limited to at least one of an electrical device, an optical device, an acoustic wave device, and the like.

[0105] It should be noted that the specific details and beneficial effects of the above electronic device embodiments can be found in the above structural embodiments or method embodiments, which will not be repeated here.

[0106] The above description has fully disclosed the specific implementation methods of the present application. It should be pointed out that any changes made by technicians familiar with the field to the specific implementation methods of the present application do not deviate from the scope of the claims of the present application. Accordingly, the scope of the claims of the present application is not limited to the above specific implementation methods.

Claims

1. A composite structure substrate, characterized in that: include: a supporting substrate; a bonding structure layer located on the supporting substrate; a functional film layer located on the bonding structure layer, wherein the functional film layer is obtained by surface treating a first functional layer and a second functional layer, a damaged layer is formed on a first surface of the first functional layer away from the supporting substrate, and the second functional layer is converted by surface treating the first functional layer; The surface treatment of the first functional layer includes: etching the first surface of the first functional layer to obtain the second functional layer; the etching thickness of the etching process is greater than the thickness of the damaged layer; The surface treatment of the second functional layer includes: performing chemical mechanical polishing on the second functional layer to remove the amorphous layer on the surface of the second functional layer, and thinning the remaining second functional layer to obtain the functional thin film layer; the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10~1.

20.

2. The composite structure substrate according to claim 1, characterized in that: The etching process is achieved by at least one of the following two methods: When the initial thickness uniformity of the first functional layer is 1-10 nm, the first functional layer is subjected to a first etching process to remove a material of a first preset thickness, thereby obtaining the second functional layer; the thickness of the second functional layer is the difference between the thickness of the first functional layer and the first preset thickness; When the initial thickness uniformity of the first functional layer is 10 to 100 nm, the second functional layer of a second preset thickness is obtained by performing a second etching treatment on the first functional layer; the material removal thickness of the second etching treatment is the difference between the thickness of the first functional layer and the second functional layer; wherein the second preset thickness includes setting the edge thickness of the second functional layer to be less than or greater than the center thickness or the thickness of one half of the second functional layer to be less than the thickness of the opposite half.

3. The composite structure substrate according to claim 1 or 2, characterized in that: The ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching process is 1:0.20-0.80; The thickness uniformity of the second functional layer is 1 to 10 nm; The surface roughness of the functional film layer is 0.05-0.5 nm.

4. The composite structure substrate according to claim 1 or 2, characterized in that: The chemical mechanical polishing treatment is performed on the second functional layer to remove the amorphous layer on the surface of the second functional layer, and the remaining second functional layer is thinned to obtain the functional thin film layer, which includes: The second functional layer is subjected to chemical mechanical polishing to remove the surface residual layer and the amorphous layer on the surface of the second functional layer, and the remaining second functional layer is thinned to obtain the functional thin film layer of the second functional layer; wherein the surface roughness of the surface residual layer is between 0.5 and 20 nm.

5. The composite structure substrate according to claim 1 or 2, characterized in that: The composite structure substrate satisfies at least one of the following: The composite structure substrate further comprises a carrier trapping layer, which is arranged between the support substrate and the bonding structure layer and is used to trap free carriers in the support substrate; The material of the functional thin film layer is at least one of single crystal lithium niobate, single crystal lithium tantalate, quartz, aluminum nitride, gallium nitride, gallium oxide, calcium fluoride, silicon, sapphire, silicon carbide, and diamond; The material of the bonding structure layer is silicon oxide; The material of the carrier trapping layer is polycrystalline silicon, amorphous silicon or porous silicon; The support substrate is at least one of silicon, silicon oxide, polysilicon, silicon on insulator, sapphire, silicon carbide, silicon carbide on insulator, quartz, aluminum nitride, gallium nitride, and diamond.

6. A method for preparing a composite structure substrate, characterized in that: include: Providing a supporting substrate, and forming an auxiliary bonding layer on a surface of the supporting substrate; Providing a functional substrate having an initial thin film functional layer formed thereon, and performing ion implantation on a surface of the functional substrate away from the initial thin film functional layer; Bonding the functional substrate and the supporting substrate via the auxiliary bonding layer to obtain a bonding structure layer; Annealing the bonding structure layer once and peeling it off from the damaged layer formed by ion implantation to form a first functional layer on the bonding structure layer; The first functional layer is subjected to secondary annealing, and the first functional layer and the second functional layer are subjected to surface treatment to form a thin film functional layer, so as to obtain a composite structure substrate; the second functional layer is formed by converting the first functional layer through surface treatment; wherein the surface treatment includes etching the first functional layer and chemical mechanical polishing the second functional layer, and the ratio of the material removal thickness of the chemical mechanical polishing to the material removal thickness of the etching treatment is 1:0.10~1.

20.

7. The method according to claim 6, characterized in that The surface treatment process satisfies at least one of the following: The etching method of the etching treatment includes at least one of physical etching, chemical etching, and physical and chemical etching; The polishing back pressure of the chemical mechanical polishing is in the range of 0.5-5.5 lbf / square inch, and the thickness of the material removed by the chemical mechanical polishing is in the range of 20-120 nm.

8. The method according to claim 7, characterized in that Before performing the etching process or the chemical mechanical polishing process, the method further comprises: The step of chamfering the edge of the first functional layer or the second functional layer, wherein the width of the chamfer is 1 to 5 mm, the depth of the chamfer is 10 to 100 um, and the shape of the chamfer is an R-shaped chamfer.

9. The method according to any one of claims 6 to 8, characterized in that: The method satisfies at least one of the following: The type of implanted ions is at least one of hydrogen ions, helium ions or argon ions, the implantation energy is between 20 KeV and 300 KeV, and the implantation dose is 1E14 ions / cm 2 to 1E17 ions / cm 2 ; The bonding structure layer is annealed at a temperature of 100° C. to 400° C., and the atmosphere of the heat treatment is at least one of an inert gas, nitrogen, oxygen, and a vacuum environment; The temperature of the secondary annealing of the first functional layer is 200° C. to 1200° C., and the atmosphere of the heat treatment is at least one of an inert gas, oxygen, nitrogen, and a vacuum environment.

10. An electronic device, characterized in that: The electronic device comprises: A composite structure substrate according to any one of claims 1 to 5, or a composite structure substrate prepared by the method according to any one of claims 6 to 9; The surface electrode is arranged on the surface of the thin film functional layer in the composite structure substrate.

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