A method for manufacturing a hetero thin film substrate and a filter

Abstract

The application relates to a preparation method of a heterogeneous thin film substrate and a filter. The method comprises the following steps: providing a thin film transfer substrate, the thin film transfer substrate having opposite first and second surfaces; performing ion implantation on the thin film transfer substrate to form an implantation damage layer in the thin film transfer substrate; the direction of the ion implantation is from the first surface to the second surface; providing a support substrate, the support substrate having opposite third and fourth surfaces; bonding the third surface of the support substrate with the first surface of the thin film transfer substrate to obtain a bonded substrate; and performing heat treatment on the bonded substrate, and applying a deformation limiting pressure with a preset size on the bonded substrate during the heat treatment to make the bonded substrate peel along the implantation damage layer to obtain the heterogeneous thin film substrate. The application guarantees the integrity of the transferred thin film layer when the bonded substrate is peeled by applying the deformation limiting pressure with the preset size.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material preparation technology and radio frequency devices, and particularly relates to a preparation method of a hetero thin film substrate and a filter. BACKGROUND

[0002] With the increasing pursuit of the data transmission speed, performance, power consumption and the like of telecommunication equipment, people need to provide new chip integration schemes to realize high-performance, high-integration and low-power chip technology. According to the different properties of materials, people have realized chips with different superior performances based on the superior performance of the materials themselves. For example, silicon chips with high integration, gallium arsenide chips with high speed and high frequency, gallium nitride chips with high power, and piezoelectric chips are widely used in filters of radio frequency systems. The rise of piezoelectric thin films enables related optical and acoustic devices to greatly reduce device size, improve work efficiency, and realize novel working modes.

[0003] At present, the integration of piezoelectric materials and silicon will provide a wafer substrate for material-level integration, providing a material platform for the preparation of single-chip integrated modules. The current hetero-substrate wafer preparation filter can effectively improve the center frequency, bandwidth and reduce the power consumption and heat dissipation of the related filter. In the preparation process of the wafer substrate, the related technology usually uses an ion beam lift-off method to transfer the piezoelectric single crystal to the required substrate, but the thin film substrate will face a huge thermal stress after being heated by the ion beam lift-off method, which is easy to cause deformation release (see Figure 9 ), affecting the structure of the thin film layer and the transfer effect. Therefore, an improved preparation scheme of a hetero thin film substrate is needed to solve the above problems. SUMMARY

[0004] In view of the above problems of the prior art, the present application provides a preparation method of a hetero thin film substrate and a filter to solve the technical problems of interface acoustic wave energy reflection in the device structure in the prior art. The specific technical scheme is as follows:

[0005] In one aspect, the present application provides a preparation method of a hetero thin film substrate, which comprises:

[0006] providing a thin film transfer substrate, the thin film transfer substrate having opposite first and second surfaces;

[0007] ion implanting the thin film transfer substrate to form an implantation damage layer in the thin film transfer substrate; the direction of the ion implantation is from the first surface to the second surface;

[0008] providing a support substrate, the support substrate having opposite third and fourth surfaces;

[0009] bonding the third surface of the support substrate and the first surface of the thin film transfer substrate to obtain a bonded substrate;

[0010] performing a heat treatment on the bonded substrate, and applying a preset magnitude of deformation limiting pressure on the bonded substrate during the heat treatment to make the bonded substrate peel off along the implantation damage layer to obtain the hetero thin film substrate.

[0011] Further, the applying of the preset magnitude of deformation limiting pressure on the bonded substrate during the heat treatment comprises applying an external force on the bonded substrate and / or placing the bonded substrate in a jig with a preset thermal expansion coefficient.

[0012] Further, the preset magnitude of deformation limiting pressure is 1-100 kN; and the preset thermal expansion coefficient of the jig is less than 50% of the thermal expansion coefficient of the bonded substrate.

[0013] Further, the material of the support substrate comprises at least one of silicon, silicon oxide, sapphire, diamond, aluminum nitride, gallium nitride, silicon carbide and silicon on insulator.

[0014] Further, the ions used in the ion implantation comprise at least one of hydrogen ions, helium ions and neon ions.

[0015] Further, the thin film transfer substrate has a semiconductor material or a piezoelectric material.

[0016] In the case that the thin film transfer substrate is a semiconductor material, the semiconductor material comprises at least one of silicon, germanium, indium phosphide, gallium nitride, silicon carbide, aluminum nitride and gallium arsenide.

[0017] In the case that the thin film transfer substrate is a piezoelectric material, the piezoelectric material comprises at least one of lithium niobate, lithium tantalate, potassium niobate and barium titanate.

[0018] Further, the temperature of the ion implantation is -25-300°C.

[0019] The implantation energy of the ion implantation is 1-2000 keV.

[0020] The dose of the ion implantation is 1×10 16 -1×10 18 cm -2 .

[0021] Further, the performing of the heat treatment on the bonded substrate comprises:

[0022] heating the bonded substrate at a heating rate of 0.1-10 ℃ / min to a peeling temperature of 100-1100 ℃ and maintaining the temperature for 1-1000 h.

[0023] Further, the obtaining the heterogeneous thin film substrate further comprises:

[0024] The heterogeneous thin film substrate is subjected to at least one of annealing treatment and surface treatment.

[0025] In another aspect, the application also provides a heterogeneous thin film substrate prepared by the above method.

[0026] In another aspect, the application also provides a filter comprising the above heterogeneous thin film substrate structure.

[0027] Thanks to the above technical solution, the preparation method of the heterogeneous thin film substrate and the filter have the following beneficial effects:

[0028] In the process of heat treatment of the bonded substrate, the bonded substrate deforms after being heated. By applying a deformation limiting pressure of a preset size to the bonded substrate, the deformation direction of the bonded substrate is limited, so that the strain of the bonded substrate is limited, so that when the bonded substrate is peeled along the implanted damage layer, complete and uniform thin film layer transfer is achieved, so that the stress generated by the bonded substrate mainly exists in the direction that is not easy to break, ensuring the integrity of the transferred thin film layer when the bonded substrate is peeled.

[0029] The filter prepared by the preparation method of the heterogeneous thin film substrate of the application optimizes the frequency offset, loss and heat dissipation of the filter, and effectively widens the application scenarios of the filter. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 is a flowchart of the preparation method of the heterogeneous thin film substrate provided by the embodiments of the application;

[0032] Figure 2 is a structural schematic diagram of the thin film transfer substrate provided by the embodiments of the application;

[0033] Figure 3is a structural schematic diagram of a thin film transfer substrate after ion implantation provided by an embodiment of the present application;

[0034] Figure 4 is a structural schematic diagram of a support substrate provided by an embodiment of the present application;

[0035] Figure 5 is a structural schematic diagram of a bonded substrate provided by an embodiment of the present application;

[0036] Figure 6 is a structural schematic diagram of a hetero thin film substrate provided by an embodiment of the present application;

[0037] Figure 7 is a structural schematic diagram of a filter provided by an embodiment of the present application;

[0038] Figure 8 is a deformation schematic diagram of a bonded substrate after a preset size of deformation limiting pressure is applied to the bonded substrate during heat treatment provided by an embodiment of the present application;

[0039] Figure 9 is a deformation schematic diagram of a bonded substrate during heat treatment provided by an embodiment of the present application.

[0040] In the figure, the reference signs correspond to: 1 - thin film transfer substrate; 2 - support substrate; 3 - metal patterned electrode; 11 - implantation damage layer; 12 - thin film transfer layer. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0042] For the following defined terms, these definitions shall be applied even if these terms are used in the claims or elsewhere in the specification. All numerical values are defined with acceptable limits by the term“about” whether or not explicitly indicated. The term“about” generally means a range of values, which those of ordinary skill in the art will recognize as equivalent to the stated value to produce substantially the same properties, functions, results, etc. A numerical range is defined by a lower value and an upper value, and includes all numerical values between the lower and upper values, and all sub-ranges included within the numerical range.

[0043] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present disclosure and the above-described accompanying drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0044] The following describes the acoustic wave resonator preparation method provided by the embodiments of the present application. Please refer to Figure 1 , Figure 1 is a flowchart of the preparation method of the hetero thin film substrate. The present specification provides method operation steps such as embodiments or flowcharts, but can include more or fewer operation steps based on conventional or non-inventive labor. The order of the steps listed in the embodiments is only one of the many execution orders, and does not represent the only execution order. In actual preparation method execution, the method order shown in the embodiments or the accompanying drawings can be executed or executed in parallel. The method includes:

[0045] S100: providing a thin film transfer substrate 1, the thin film transfer substrate 1 having opposite first and second surfaces. The thin film transfer substrate 1 has a semiconductor material or a piezoelectric material. Please refer to Figure 2 , Figure 2 is a structural diagram of the thin film transfer substrate provided by the embodiments of the present application.

[0046] In some embodiments, in the case of the thin film transfer substrate 1 being a semiconductor material, the semiconductor material includes at least one of silicon, germanium, indium phosphide, gallium nitride, silicon carbide, aluminum nitride, and gallium arsenide.

[0047] In other embodiments, in the case of the thin film transfer substrate 1 being a piezoelectric material, the piezoelectric material includes at least one of lithium niobate, lithium tantalate, potassium niobate, and barium titanate.

[0048] S200: ion implantation is performed on the thin film transfer substrate 1 to form an implantation damage layer 11 in the thin film transfer substrate 1; the direction of ion implantation is from the first surface to the second surface. The ion implantation depth is not limited here, and the implantation damage layer 11 is formed inside the thin film transfer substrate 1 close to one side of the first surface. Please refer to Figure 3 , Figure 3 is a structural diagram of the thin film transfer substrate after ion implantation provided by the embodiments of the present application.

[0049] In some embodiments, the ions used for ion implantation include at least one of hydrogen ions, helium ions, and neon ions.

[0050] The temperature of ion implantation is -25 to 300°C;

[0051] The implantation energy of ion implantation is 1-2000 keV;

[0052] The dose of ion implantation is 1x10 16 -1x10 18 cm -2 .

[0053] S300: providing a support substrate 2, the support substrate 2 having opposite third and fourth surfaces.

[0054] In some embodiments, the material of the support substrate 2 comprises at least one of silicon, silicon oxide, sapphire, diamond, aluminum nitride, gallium nitride, silicon carbide, and silicon on insulator. Please refer to Figure 4 FIG. 4 is a structural schematic diagram of a support substrate provided by an embodiment of the present application.

[0055] S400: bonding the third surface of the support substrate 2 with the first surface of the thin film transfer substrate 1, to obtain a bonded substrate. Please refer to Figure 5 Figure 5 FIG. 5 is a structural schematic diagram of a bonded substrate provided by an embodiment of the present application.

[0056] In actual applications, the method and conditions of bonding the support substrate 2 and the thin film transfer substrate 1 can be the same as those in the prior art, and the present application does not make any limitation.

[0057] S500: performing heat treatment on the bonded substrate, and applying a deformation limiting pressure of a preset size on the bonded substrate during the heat treatment, so as to make the bonded substrate peel along the implantation damage layer 11, to obtain a hetero thin film substrate. Please refer to Figure 6 Figure 6 FIG. 6 is a structural schematic diagram of a hetero thin film substrate provided by an embodiment of the present application. The direction of applying the deformation limiting pressure of a preset size on the bonded substrate can be along the thickness direction (out-of-plane) of the bonded substrate and / or along the peripheral direction (in-plane) of the bonded substrate. Please refer to Figure 8 Figure 8 FIG. 7 is a deformation schematic diagram of the bonded substrate provided by an embodiment of the present application after applying the deformation limiting pressure of a preset size on the bonded substrate during the heat treatment;

[0058] In some embodiments, the heat treatment on the bonded substrate comprises:

[0059] ​​​The bonding substrate is heated at a heating rate of 0.1-10 ℃ / min to a peeling temperature of 100-1100 ℃ and is kept for 1-1000 h. A preset size of deformation limiting pressure is applied to the bonding substrate during the heat treatment, including: applying an external force to the bonding substrate and / or placing the bonding substrate in a jig with a preset thermal expansion coefficient.

[0060] In some embodiments, the preset size of deformation limiting pressure can be applied to the bonding substrate by a commonly used bonder such as Suss or EVG. Specifically, the preset size of deformation limiting pressure can be 1-100 kN, 1-50 kN, 50-100 kN, or 40-80 kN.

[0061] In other embodiments, the bonding substrate can be placed in a jig with a preset thermal expansion coefficient. Specifically, the preset thermal expansion coefficient is less than 50% of the thermal expansion coefficient of the bonding substrate.

[0062] During the heat treatment of the bonding substrate in the present application, the bonding substrate will deform after being heated. By applying a preset size of deformation limiting pressure to the bonding substrate, a limitation is applied in the deformation direction of the bonding substrate, thereby realizing the limitation of the strain of the bonding substrate, so that the bonding substrate realizes complete and uniform thickness of the transferred film layer when being peeled along the implanted damage layer 11, so that the stress generated by the bonding substrate mainly exists in the direction in which fragmentation is not easy to occur, thereby ensuring the integrity of the transferred film layer when the bonding substrate is peeled.

[0063] In some embodiments, obtaining the heterogeneous thin film substrate further includes at least one of annealing treatment and surface treatment on the heterogeneous thin film substrate. The roughness of the surface of the heterogeneous thin film substrate is reduced by annealing treatment and / or surface treatment on the heterogeneous thin film substrate. Specifically, the roughness of the surface of the heterogeneous thin film substrate can be reduced to 0.1-3 nm.

[0064] On the other hand, the present application also provides a filter including a heterogeneous thin film substrate structure prepared by the preparation method of the heterogeneous thin film substrate as above. The filter includes: depositing a metal patterned electrode 3 (such as shown in Figure 7 ) on the surface of the heterogeneous thin film substrate away from the thin film transfer substrate 1, to obtain the filter. Specifically, the patterned electrode can be an interdigital electrode.

[0065] Embodiment 1

[0066] The present embodiment 1 discloses a preparation method of a filter, and the preparation method includes the following steps:

[0067] S100: providing a thin film transfer substrate 1, the thin film transfer substrate 1 having opposite first and second surfaces. The thin film transfer substrate 1 is a silicon semiconductor material.

[0068] S200: performing ion implantation on the thin film transfer substrate 1 to form an implantation damage layer 11 in the thin film transfer substrate 1; the direction of the ion implantation is from the first surface to the second surface. The implantation damage layer 11 is formed on the side of the thin film transfer substrate 1 close to the first surface.

[0069] In some embodiments, the ions used in the ion implantation include at least one of hydrogen ions, helium ions, and neon ions.

[0070] The temperature of the ion implantation is -25 to 300°C;

[0071] The implantation energy of the ion implantation is 1-2000 keV;

[0072] The dose of the ion implantation is 1x10 16 -1x10 18 cm -2 .

[0073] S300: providing a support substrate 2, the support substrate 2 having opposite third and fourth surfaces.

[0074] The material of the support substrate 2 is lithium tantalate.

[0075] S400: bonding the third surface of the support substrate 2 with the first surface of the thin film transfer substrate 1 to obtain a lithium tantalate / silicon bonded substrate.

[0076] In practical applications, the method and conditions for bonding the support substrate 2 and the thin film transfer substrate 1 can be the same as those in the prior art, and the present disclosure is not limited.

[0077] S500: performing heat treatment on the lithium tantalate / silicon bonded substrate, and applying a preset size of deformation limiting pressure on the bonded substrate during the heat treatment to make the bonded substrate peel off along the implantation damage layer 11 to obtain a hetero thin film substrate.

[0078] In some embodiments, the heat treatment on the lithium tantalate / silicon bonded substrate includes:

[0079] The lithium tantalate / silicon bonded substrate is heated at a heating rate of 0.1-10°C / min until the peeling temperature of 200°C is reached, and the temperature is maintained for 100 h.

[0080] In one embodiment, during the heat treatment, a preset size of deformation limiting pressure is applied to the thickness direction (out-of-plane direction) of the bonded substrate by a commonly used bonder such as Suss or EVG. Specifically, the preset size of deformation limiting pressure is 10-30 kN. During the heating process of the lithium tantalate / silicon bonded substrate, the lithium tantalate / silicon bonded substrate is prevented from excessive deformation, thereby facilitating the smooth transfer of the implanted transfer film layer to the support substrate 2.

[0081] In another embodiment, during the heat treatment, the direction of the maximum strain of the lithium tantalate / silicon bonded substrate can be the in-plane direction of the lithium tantalate / silicon bonded substrate. During the heating process, the lithium tantalate / silicon bonded substrate is placed in a fixture with a low coefficient of thermal expansion, such as a quartz boat, where the fixture with a low coefficient of thermal expansion refers to a fixture with a coefficient of thermal expansion less than 50% of the coefficient of thermal expansion of the bonded substrate. During the heating process, the large thermal expansion of the lithium tantalate / silicon bonded substrate is limited by the quartz boat, achieving the peeling of the bonded substrate along the implantation damage layer 11 under a large stress, thereby facilitating the smooth transfer of the implanted transfer film layer to the support substrate 2 to obtain a hetero thin film substrate.

[0082] During the heat treatment of the bonded substrate in the present application, the bonded substrate will deform after being heated. By applying a preset size of deformation limiting pressure to the bonded substrate, the deformation direction of the bonded substrate is limited, thereby achieving the limitation of the strain of the bonded substrate, so that the bonded substrate can be peeled along the implantation damage layer, achieving complete and uniform thickness of the transferred film layer. The stress generated by the bonded substrate mainly exists in the direction that is not prone to fragmentation, ensuring the integrity of the transferred film layer during the peeling of the bonded substrate.

[0083] In some embodiments, after obtaining the hetero thin film substrate, at least one of annealing treatment and surface treatment is performed on the hetero thin film substrate. The annealing treatment and / or surface treatment is performed on the hetero thin film substrate to reduce the roughness of the surface of the hetero thin film substrate. Specifically, the roughness of the surface of the hetero thin film substrate can be reduced to 0.1-3 nm.

[0084] A metal patterned electrode 3 (such as shown in FIG. 1) is deposited on the side surface of the hetero thin film substrate away from the support substrate 2, thereby obtaining a filter. Specifically, the patterned electrode can be an interdigital electrode. Figure 7

[0085] Thanks to the above technical solutions, the preparation method of a hetero thin film substrate and the filter have the following beneficial effects:

[0086] ​In the process of heat treatment of the bonding substrate, the bonding substrate is deformed after being heated. By applying a preset deformation limiting pressure to the bonding substrate, a limitation is applied to the deformation direction of the bonding substrate, thereby realizing the limitation of the strain of the bonding substrate. When the bonding substrate is peeled along the implanted damage layer 11, complete and uniform thickness film layer transfer is realized, so that the stress generated by the bonding substrate mainly exists in the direction in which fragmentation is not easy to occur, thereby ensuring the integrity of the transferred film layer when the bonding substrate is peeled.

Claims

1. A method for producing a hetero thin film substrate, characterized by, The method comprises the following steps: providing a thin film transfer substrate (1) having opposite first and second surfaces; performing ion implantation on the thin film transfer substrate (1) to form an implantation damage layer (11) in the thin film transfer substrate (1); the ion implantation is performed from the first surface to the second surface; providing a support substrate (2) having opposite third and fourth surfaces; bonding the third surface of the support substrate (2) to the first surface of the thin film transfer substrate (1) to obtain a bonded substrate; performing a heat treatment on the bonded substrate to a temperature reaching a peeling temperature of the bonded substrate; applying a deformation limiting pressure of a preset size on the bonded substrate during the heat treatment, the deformation limiting pressure being applied in a direction along a thickness direction of the bonded substrate and / or a direction along a periphery of the bonded substrate, so that the bonded substrate can be completely peeled along the implantation damage layer (11) to obtain the hetero thin film substrate.

2. The method for producing a heterogeneous thin film substrate according to claim 1, wherein The step of applying the deformation limiting pressure of the preset size on the bonded substrate during the heat treatment comprises: applying an external force on the bonded substrate and / or placing the bonded substrate in a jig having a preset thermal expansion coefficient.

3. The method according to claim 2, wherein: the deformation limiting pressure of the preset size is 1-100 kN; and the preset thermal expansion coefficient is less than 50% of a thermal expansion coefficient of the bonded substrate.

4. The method of claim 1, wherein the hetero thin film substrate is a single crystal substrate. The material of the support substrate (2) comprises at least one of silicon, silicon oxide, sapphire, diamond, aluminum nitride, gallium nitride, silicon carbide, and silicon on insulator.

5. The method of claim 1, wherein the hetero thin film substrate is a single crystal substrate. The ions used in the ion implantation comprise at least one of hydrogen ions, helium ions, and neon ions.

6. The method of claim 1, wherein the hetero thin film substrate is a single crystal substrate. The thin film transfer substrate (1) comprises a semiconductor material or a piezoelectric material. In the case where the thin film transfer substrate (1) is a semiconductor material, the semiconductor material comprises at least one of silicon, germanium, indium phosphide, gallium nitride, silicon carbide, aluminum nitride, and gallium arsenide. In the case where the thin film transfer substrate (1) is a piezoelectric material, the piezoelectric material comprises at least one of lithium niobate, lithium tantalate, potassium niobate, and barium titanate.

7. The method of claim 1, wherein the hetero thin film substrate is a single crystal substrate. The temperature of the ion implantation is 25-300 °C. The implantation energy of the ion implantation is 1-2000 keV. The ion implantation dose is 1 x 10 16 -1 x 10 18 cm -2 .

8. The method of claim 1, wherein the hetero thin film substrate is a single crystal substrate. The heat treatment on the bonded substrate comprises: heating the bonded substrate at a heating rate of 0.1-10 °C / min to a peeling temperature of 100-1100 °C and maintaining the temperature for 1-1000 h.

9. The method of claim 1, wherein After obtaining the hetero thin film substrate, the method further comprises: performing at least one of an annealing treatment and a surface treatment on the hetero thin film substrate.

10. A filter, characterized by, A hetero thin film substrate structure obtained by the method according to any one of claims 1-9.

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