Disclosure of Invention
The application provides a method for preparing a composite film by microwave heating, the composite film and an electronic component, and aims to solve the problem that in the prior art, due to the fact that thermal expansion coefficients of a single crystal wafer and a substrate layer are inconsistent during annealing separation, the single crystal wafer bonded on the substrate layer warps, and when the separation critical point is reached, the warping is recovered instantly, so that the thin film layer is broken.
In a first aspect, embodiments of the present application provide, in part, a method for preparing a composite film by microwave heating, the method comprising:
performing ion implantation treatment on the single crystal wafer, wherein the adopted implanted ions are polar ions, and obtaining a single crystal wafer implantation piece with a three-layer structure comprising a residual layer, a polar implantation layer and a thin film layer;
bonding the single crystal wafer injection piece and the substrate wafer pre-matched with the single crystal wafer to obtain a bonding body with a bonding interface containing polar molecules;
heating the bonding body by using a microwave generator according to preset process parameters until the polar injection layer is separated from the thin film layer, so as to obtain the single crystal piezoelectric composite film after the residual layer is stripped; the preset process parameters comprise: and heating the bonding body to a preset temperature and keeping the bonding body for a preset time.
Optionally, the frequency of the microwave generated by the microwave generator is 300MHz-30000 MHz.
Optionally, the preset temperature is 100-600 ℃.
Optionally, the preset time period is 1 minute to 48 hours.
Optionally, the polar ion is selected to be CO+Or H2O+。
Optionally, theThe polar ion parameters were: the injection amount is 1 × 1015ions/cm2To 5X 1018ions/cm2(ii) a The implantation energy is 50-2000 keV.
Optionally, an insulating layer is manufactured on one surface of the substrate wafer pre-matched with the single crystal wafer to obtain a substrate wafer, and the single crystal wafer implantation piece is bonded with the insulating layer of the substrate wafer.
Optionally, the insulating layer is one of silicon dioxide, silicon oxynitride, and silicon nitride.
Optionally, the single crystal wafer is a lithium niobate single crystal wafer or a lithium tantalate single crystal wafer.
Optionally, the substrate wafer is a silicon wafer, a silicon carbide wafer, silicon nitride, quartz, sapphire or quartz glass.
Optionally, the manufacturing of the insulating layer on one side of the substrate wafer includes:
manufacturing a dielectric layer on one surface of the substrate wafer;
and manufacturing an insulating layer on the dielectric layer.
Optionally, the method for manufacturing the dielectric layer adopts a deposition method to deposit polycrystalline silicon or amorphous silicon, or adopts an etching method to generate an etching damage layer on the surface of monocrystalline silicon, or generates an injection damage layer by an injection method.
In a second aspect, the present application provides, in part, a composite film prepared by the method of any one of the first aspect.
In a third aspect, an embodiment of the present application provides an electronic component, where the electronic component includes the composite film according to the second aspect.
The method for preparing the composite film by microwave heating, the composite film and the electronic component have the following beneficial effects:
firstly, the bonding body is heated and stripped by using a microwave generator, and because polar ions are implanted into a single crystal wafer, the polar ions are CO or H losing one charge2O, getting electrons from the single crystal wafer into polar molecules after the polar ions enter the single crystal wafer,microwave heating only heats the implanted layer implanted with polar ions, and does not heat the substrate wafer and the single crystal wafer, so that the situation that the bonded composite film is bent during heat treatment to fracture a certain layer or the whole composite film due to different thermal expansion coefficients of the single crystal wafer and the substrate wafer during annealing separation does not occur;
secondly, the molecules in the heated medium material in the microwave heating are polar molecules, and the polar orientation of the molecules is changed along with the change of an external electric field under the action of a rapidly changed high-frequency electromagnetic field, so that the movement and mutual friction effects of the molecules are caused. At the moment, the field energy of the microwave field is converted into the heat energy in the medium, so that the temperature of the material is raised, and a series of physical and chemical processes of thermalization and puffing are generated to achieve the purpose of microwave heating.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to solve the problem that the single crystal wafer and the substrate wafer are different in material, when a bonding body of the non-homogeneous single crystal wafer and the substrate wafer is subjected to heat treatment, the single crystal wafer is warped due to the fact that expansion coefficients of the single crystal wafer and the substrate wafer are different during annealing separation, when separation occurs under the critical separation condition, a residual layer is peeled off from the substrate layer, a warped thin film layer is instantly restored to a flat state, and the thin film layer is broken due to too large restoring force. The embodiment of the application provides a single crystal piezoelectric composite film, on the basis of the existing composite film, a bonding body is heated through a microwave generator heating process, microwave heating only acts on a polar injection layer, and the situation that a certain layer or the whole of the composite film is broken due to the fact that thermal expansion coefficients of a single crystal wafer and a substrate wafer are different when the single crystal wafer and the substrate wafer are separated is avoided.
Referring to fig. 1, a schematic flow chart of a method for preparing a composite film by microwave heating according to the present application is shown;
as can be seen in fig. 1, the present application provides a method for preparing a composite film by microwave heating, the method comprising:
s101: performing ion implantation treatment on the single crystal wafer, wherein the adopted implanted ions are polar ions, and obtaining a single crystal wafer implantation piece with a three-layer structure comprising a residual layer, a polar implantation layer and a thin film layer;
the method comprises performing ion implantation on single crystal wafer, wherein the implanted polar ions are CO+Or H2O+(ii) a For example CO injection+The depth of the polar ion implantation is determined by the implantation energy, and the implantation amount is 1 × 1015ions/cm2To 5X 1018ions/cm2The implantation energy is 50-2000 keV; in this step, after the polar ions enter the single crystal wafer, electrons are obtained from the single crystal wafer to become polar molecules, and a polar injection layer is formed; in this embodiment, the single crystal wafer may be a lithium niobate single crystal wafer or a lithium tantalate single crystal wafer, which may be selected according to needs and is not specifically limited herein;
s102: bonding the single crystal wafer injection piece and the substrate wafer pre-matched with the single crystal wafer to obtain a bonding body with a bonding interface containing polar molecules;
in this embodiment, the bonding manner is not limited, and a substrate wafer can be obtained by fabricating an insulating layer on one surface of the substrate wafer pre-matched with the single crystal wafer; a dielectric layer can be manufactured on one surface of the non-homogeneous substrate wafer, and then an insulating layer is manufactured on the dielectric layer;
in practical application, the insulating layer can be prepared by a deposition method, and the manner of preparing the insulating layer by the deposition method is not limited, and is Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), magnetron sputtering and the like; the Chemical Vapor Deposition (CVD) may use LPCVD (Low Pressure Chemical Vapor deposition) method or PECVD (Plasma Enhanced Chemical Vapor deposition) method to fabricate the insulating layer, and any one of the prior art methods may be used to fabricate the insulating layer on one side of the substrate wafer, which is not limited herein;
in this embodiment, the substrate wafer may be a silicon wafer, a silicon carbide wafer, silicon nitride, quartz, sapphire, or quartz glass, and the method for manufacturing the dielectric layer adopts a deposition method to deposit polycrystalline silicon or amorphous silicon, or adopts an etching method to generate an etching damage layer on the surface of monocrystalline silicon, or generates an injection damage layer by an implantation method; in this embodiment, the material of the substrate wafer, the insulating layer and the dielectric layer are not limited in the manufacturing method;
s103: heating the bonding body by using a microwave generator according to preset process parameters until the polar injection layer is separated from the thin film layer, so as to obtain the single crystal piezoelectric composite film after the residual layer is stripped; the preset process parameters comprise: and heating the bonding body to a preset temperature and keeping the bonding body for a preset time.
The principle of microwave heating is as follows: the molecules in the heated medium material in microwave heating are polar molecules, and under the action of a rapidly-changing high-frequency electromagnetic field, the polar orientation of the polar molecules is changed along with the change of an external electric field, so that the movement and mutual friction effects of the molecules are caused. At the moment, the field energy of the microwave field is converted into the heat energy in the medium, so that the temperature of the material is raised, and a series of physical and chemical processes of thermalization and puffing are generated to achieve the purpose of microwave heating.
In the prior art, when a bonding body is heated, if a single crystal wafer and a substrate layer are made of two different materials, the single crystal wafer bonded on the substrate layer can warp due to the fact that thermal expansion coefficients of the single crystal wafer and the substrate layer are different during annealing separation, when separation occurs when a critical separation condition is reached, a residual layer is peeled off from the substrate layer, a warped thin film layer is instantly restored to a flat state, and the thin film layer is broken due to too large restoring force.
Referring to fig. 2, a schematic structural diagram of a method for preparing a composite film by microwave heating according to the present application is shown;
as shown in fig. 2, a microwave generator is used to heat the bonding body according to preset process parameters, and microwave heating is applied to a polar injection layer in the bonding body, i.e., heated molecules in the microwave heating are polar molecules; the residual layer at the polar injection layer is stripped, and the single crystal wafer and the substrate wafer are not heated, so that the problem of fracture of the single crystal wafer and the substrate wafer caused by the difference of thermal expansion coefficients is solved; in the step, the preset temperature is 100-600 ℃, and the preset time is 1 minute to 48 hours; in this embodiment, the preset temperature and the preset time period are not particularly limited.
Based on the method disclosed above, the embodiment of the application further discloses a composite film, and the composite film is prepared by adopting the method for preparing the composite film by microwave heating as described in any one of the above.
Based on the above-mentioned compound film that discloses, this application embodiment still discloses an electronic components, electronic components includes the aforesaid compound film.
To further illustrate the technical solutions in the present application, the embodiments of the present application further disclose the following specific examples.
Example 1
1) Preparing a 200-micron silicon wafer and a 200-micron lithium niobate wafer, respectively fixing the silicon wafer or the lithium niobate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
injecting CO into the treated lithium niobate wafer+The implantation dose is 5X 1018ions/cm2(ii) a The energy of implantation is 400keV, so that the lithium niobate wafer is implanted from the implantationThe entering face is sequentially divided into three layers of a residual layer, a polarity injection layer and a film layer, and CO is injected+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) preparing a silicon dioxide layer on the cleaned silicon wafer by adopting a PECVD method, then carrying out chemical mechanical polishing to the thickness of 100nm to obtain a smooth surface, and cleaning the semiconductor RCA to obtain a clean surface;
3) the thin film layer of the single crystal wafer injection piece is contacted with the silicon dioxide layer of the substrate wafer, and a bonding body is obtained by adopting a direct bonding method;
4) performing heating treatment of preset process parameters on the obtained bonding body by using a microwave generator, wherein the preset temperature is 600 ℃, the heat preservation time is 1 minute, the polar injection layer of the bonding body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
Example 2
1) Preparing a 200-micron quartz wafer and a 200-micron lithium niobate wafer, respectively fixing the quartz or lithium niobate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
h is injected into the processed lithium niobate wafer2O+The implantation dose is 2X 1016ions/cm2(ii) a The energy of implantation is 50keV, so that the lithium niobate wafer is sequentially divided into a residual layer, a polar implantation layer and a thin film layer from the implantation surface, and the implanted H2O+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) contacting the thin film layer of the single crystal wafer injection sheet with the substrate wafer, and bonding by adopting a direct bonding method to obtain a bonded body;
3) performing heating treatment of preset process parameters on the obtained bonded body by using a microwave generator, wherein the preset temperature is 100 ℃, the heat preservation time is 48 hours, the polar injection layer of the bonded body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
Example 3
1) Preparing a 500-micron silicon carbide wafer and a 500-micron lithium tantalate wafer, respectively fixing the silicon carbide wafer or the lithium tantalate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
h implantation of the treated lithium tantalate wafer2O+The implantation dose is 1 × 1015ions/cm2(ii) a The energy of implantation is 2000keV, so that the lithium tantalate wafer is sequentially divided into three layers, namely a residual layer, a polar implantation layer and a thin film layer from the implantation surface, and the implanted H2O+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) manufacturing amorphous silicon on the cleaned silicon carbide wafer by adopting an LPCVD (low pressure chemical vapor deposition) method to be used as a dielectric layer, wherein the thickness of the amorphous silicon is 10 micrometers; preparing a silicon dioxide layer on the dielectric layer by adopting a PECVD method, then carrying out chemical mechanical polishing until the thickness is 10 mu m to obtain a smooth surface, and cleaning the semiconductor RCA to obtain a clean surface;
3) the thin film layer of the single crystal wafer injection piece is contacted with the silicon dioxide layer of the substrate wafer, and a bonding body is obtained by adopting a direct bonding method;
4) performing heating treatment of preset process parameters on the obtained bonding body by using a microwave generator, wherein the preset temperature is 300 ℃, the heat preservation time is 5 hours, the polar injection layer of the bonding body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
Example 4
1) Preparing a 200-micron silicon nitride wafer and a 200-micron lithium niobate wafer, respectively fixing the silicon nitride wafer or the lithium niobate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
injecting CO into the treated lithium niobate wafer+The implantation dose is 4X 1017ions/cm2(ii) a The energy of implantation is 800keV, so that the lithium niobate wafer is sequentially divided into a residual layer, a polar implantation layer and a thin film layer from the implantation surface, and the implanted CO+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) preparing polysilicon on the cleaned silicon nitride wafer by an LPCVD (low pressure chemical vapor deposition) method to be used as a dielectric layer, wherein the thickness of the polysilicon is 1 mu m; a silicon dioxide layer is manufactured on the dielectric layer by adopting a thermal oxidation method, then chemical mechanical polishing is carried out until the thickness is 1 mu m, a smooth surface is obtained, and the semiconductor RCA is cleaned to obtain a clean surface;
3) contacting the thin film layer of the single crystal wafer injection piece with the silicon nitride layer of the substrate wafer, and bonding by adopting a direct bonding method to obtain a bonded body;
4) performing heating treatment of preset process parameters on the obtained bonding body by using a microwave generator, wherein the preset temperature is 500 ℃, the heat preservation time is 1 hour, the polar injection layer of the bonding body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
Example 5
1) Preparing a piece of 300 mu m quartz glass and a piece of 400 mu m lithium tantalate wafer, respectively fixing the quartz glass or the lithium tantalate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
CO injection into the treated lithium tantalate wafer+The implantation dose is 4X 1016ions/cm2(ii) a Energy of injectionThe amount is 400keV, the lithium niobate wafer is sequentially divided into a residual layer, a polar injection layer and a thin film layer from the injection surface, and CO is injected+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) manufacturing amorphous silicon on the cleaned quartz glass by adopting an LPCVD (low pressure chemical vapor deposition) method to be used as a dielectric layer, wherein the thickness of the amorphous silicon is 500 nm; preparing a silicon dioxide layer on the dielectric layer by adopting a PECVD method, then carrying out chemical mechanical polishing until the thickness is 5 mu m to obtain a smooth surface, and cleaning the semiconductor RCA to obtain a clean surface;
3) the thin film layer of the single crystal wafer injection piece is contacted with the silicon dioxide layer of the substrate wafer, and a bonding body is obtained by adopting a direct bonding method;
4) performing heating treatment of preset process parameters on the obtained bonding body by using a microwave generator, wherein the preset temperature is 280 ℃, the heat preservation time is 10 hours, the polar injection layer of the bonding body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
Example 6
1) Preparing a 410-micron silicon carbide wafer and a 300-micron lithium niobate wafer, respectively fixing the silicon carbide wafer or the lithium niobate wafer on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment to obtain a smooth surface, and then carrying out semiconductor RCA cleaning on the two wafers to obtain a clean surface;
injecting CO into the treated lithium niobate wafer+The implantation dose is 2X 1016ions/cm2(ii) a The energy of implantation is 1000keV, so that the lithium niobate wafer is sequentially divided into a residual layer, a polar implantation layer and a thin film layer from the implantation surface, and the implanted CO+The ions are distributed on the polar injection layer to obtain a single crystal wafer injection piece;
2) a damaged layer of the silicon carbide is manufactured on the cleaned silicon carbide wafer by adopting an injection method and is used as a dielectric layer, and the thickness of the damaged layer is 1 mu m; preparing a silicon dioxide layer on the dielectric layer by adopting a PECVD method, then carrying out chemical mechanical polishing until the thickness is 500nm to obtain a smooth surface, and cleaning the semiconductor RCA to obtain a clean surface;
3) the thin film layer of the single crystal wafer injection piece is contacted with the silicon dioxide layer of the substrate wafer, and a bonding body is obtained by adopting a direct bonding method;
4) performing heating treatment of preset process parameters on the obtained bonding body by using a microwave generator, wherein the preset temperature is 400 ℃, the heat preservation time is 2 hours, the polar injection layer of the bonding body is separated from the thin film layer, and the residual layer is stripped off to obtain a composite film of the residual thin film layer bonded on the substrate wafer; and fixing the composite film on a porous ceramic sucker of polishing equipment, carrying out chemical mechanical polishing treatment on the film layer, and then carrying out RCA cleaning to obtain a clean surface.
The above examples are only for illustrating the method of preparing the composite film by microwave heating, and do not represent a limitation to the method of preparing the composite film by microwave heating. The various steps or parameters in the foregoing embodiments may also be combined in other ways, and will not be described here. The technical solutions formed by the combination of the aforementioned steps or parameters are also within the scope of the present application.
The embodiment of the application provides a method for preparing a composite film by microwave heating, wherein the method comprises the following steps: performing ion implantation treatment on the single crystal wafer, wherein the adopted implanted ions are polar ions, and obtaining a single crystal wafer implantation piece with a three-layer structure comprising a residual layer, a polar implantation layer and a thin film layer; bonding the single crystal wafer injection piece and the substrate wafer pre-matched with the single crystal wafer to obtain a bonding body with a bonding interface containing polar molecules; heating the bonding body by using a microwave generator according to preset process parameters until the polar injection layer is separated from the thin film layer, so as to obtain the single crystal piezoelectric composite film after the residual layer is stripped; the preset process parameters comprise: and heating the bonding body to a preset temperature and keeping the bonding body for a preset time. According to the method, the difference of thermal expansion coefficients of the single crystal wafer and the substrate wafer can not be generated by utilizing the method of acting microwave heating on polar molecules, so that the partial or integral fracture of the composite film can not be caused, the yield of the composite film is improved, and the production cost of the composite film is reduced.
The present application has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to limit the application. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the presently disclosed embodiments and implementations thereof without departing from the spirit and scope of the present disclosure, and these fall within the scope of the present disclosure. The protection scope of this application is subject to the appended claims.