Polyamine compounds, flexible substrate BAW devices and preparation methods thereof
By using polyamine compounds as buffer layer during AlN film growth, the problem of excessive bonding force between AlN and the hard substrate is solved, and high-quality separation and efficient preparation of flexible BAW devices are achieved.
Patent Information
- Application Number
- CN202411926040.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-08
AI Technical Summary
In the prior art, the bonding force between AlN and the hard substrate is too strong and difficult to separate, resulting in difficulties in replacing the flexible substrate.
By depositing the compound on a heterogeneous substrate, the lattice mismatch and thermal adaptation between AlN and the substrate is alleviated, and the buffer layer is removed by organic solvent when needed, so as to facilitate separation.
High-quality separation between AlN film and substrate is achieved, the preparation process of flexible substrate BAW devices is simplified, and the efficiency and quality of the process are improved.
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Figure CN119775217A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a polyamine compound, a flexible substrate BAW device and a preparation method thereof, and belongs to the technical field of semiconductor materials and electronic communication devices. Background Art
[0002] AlN (aluminum nitride) has become the preferred material for RF devices based on piezoelectric films due to its high acoustic velocity and large quality factor. Currently, AlN materials are mainly grown directly on sapphire, SiC (silicon carbide) or Si substrates. There are a series of problems such as lattice mismatch and thermal mismatch between AlN and heterogeneous substrates, which makes the growth of AlN more difficult, and usually faces problems such as slow growth rate and poor crystal quality.
[0003] Many buffer layers have been developed in the prior art to alleviate the lattice mismatch and thermal mismatch between AlN and foreign substrates. Most of these buffer layers are made by physical vapor deposition methods. The lattice mismatch and thermal mismatch between AlN and foreign substrates are alleviated by gradually changing the elements in the buffer layers, or by alternating the stacking of two materials to alleviate the lattice mismatch and thermal mismatch between AlN and foreign substrates.
[0004] In order to meet the requirements of flexible wearable and portable devices, RF filters need to have flexible substrates. When making BAW devices (bulk acoustic wave filters) with flexible substrates, it is necessary to first complete the preparation of each layer on a hard substrate such as sapphire, silicon carbide or silicon, and finally replace the hard substrate with a flexible substrate. However, the buffer layer prepared by the physical vapor deposition method above causes the AlN to have a very strong bonding force with the hard substrate, making it difficult to separate, which causes difficulties when replacing the flexible substrate. Summary of the invention
[0005] In order to overcome the shortcomings of the prior art, the present invention provides a polyamine compound and a preparation method thereof. When the polyamine compound is applied to the growth of aluminum nitride film, the lattice mismatch and thermal mismatch between AlN and a foreign substrate can be alleviated, and the AlN and the foreign substrate will not be difficult to separate. Therefore, a flexible substrate BAW device and a preparation method thereof are also provided.
[0006] The technical solution adopted by the present invention to solve its technical problem is: In a first aspect, the present application provides a polyamine compound having a structure of formula D: ; Among them, R m , R n It is an amino group, a double bond, a triple bond, a hydrogen atom or a halogen atom.
[0007] When the polyamine compounds provided in the present application are used as a buffer layer for depositing aluminum nitride on a foreign substrate, they can alleviate the lattice mismatch and thermal adaptation between the AlN film and the substrate, and can be removed with an organic solvent later to facilitate the separation of the aluminum nitride film from the foreign substrate.
[0008] In a second aspect, the present application provides a method for preparing a polyamine compound, comprising the steps shown in reaction formula group 1: Reaction group 1; Dissolve the compound having the structure of formula A in a solvent, add ammonia water and a phase transfer catalyst, react at 0°C to 25°C for 8h to 24h, stop the reaction, cool, filter, and perform column chromatography to obtain a compound having the structure of formula B; Dissolve the compound having the structure of formula B in a solvent, add iodomethane, react at 25°C to 50°C for 12h to 24h, stop the reaction, cool, filter, and recrystallize to obtain a compound having the structure of formula C; Catalytically hydrogenating a compound having a structure of Formula C to obtain a compound having a structure of Formula D; Among them, R m , R n It is an amino group, a double bond, a triple bond, a hydrogen atom or a halogen atom.
[0009] In a third aspect, the present application provides a method for preparing a flexible substrate BAW device, comprising the following steps: Spin-coating a polyamine compound solution on a hard substrate to form a buffer layer, wherein the solute of the polyamine compound solution is the polyamine compound described in the first aspect; sequentially forming an AlN piezoelectric film, a bottom electrode, and a first SiO2 layer on the buffer layer to obtain a first epitaxial wafer; dry-etching the first SiO2 layer on the first epitaxial wafer to form a groove in the center of the first SiO2 layer; Depositing a second SiO2 layer on the flexible substrate to obtain a second epitaxial wafer; Bonding the first epitaxial wafer to the second epitaxial wafer with the first SiO2 layer facing the second SiO2 layer so that the groove becomes a cavity to obtain a bonded epitaxial wafer; Soaking the bonded epitaxial wafer in an organic solvent to dissolve the buffer layer, and peeling off the hard substrate to expose the AlN piezoelectric film; A top electrode is prepared on the AlN piezoelectric film to obtain the flexible substrate BAW device.
[0010] This method can form a high-quality AlN piezoelectric film on the buffer layer. When transferring the substrate, the buffer layer is easy to remove, making it easy to separate the hard substrate and the aluminum nitride film (AlN piezoelectric film), which is convenient for making flexible substrate BAW devices.
[0011] Furthermore, the step of sequentially forming an AlN piezoelectric film, a bottom electrode, and a first SiO2 layer on the buffer layer comprises: Depositing an AlN seed layer on the buffer layer by PVD; Growing an AlN layer on the AlN seed layer by MOCVD; the AlN seed layer and the AlN layer constitute the AlN piezoelectric film; Depositing the bottom electrode on the AlN layer by PVD; Depositing the first SiO2 layer on the bottom electrode by PECVD; The step of depositing a second SiO2 layer on the flexible substrate comprises: A second SiO2 layer was deposited on the flexible substrate using PECVD.
[0012] Further, the temperature for growing the AlN layer is greater than the temperature for depositing the AlN seed layer. The temperature for depositing the first SiO2 layer is greater than the temperature for depositing the bottom electrode. The temperature for depositing the second SiO2 layer is greater than the temperature for bonding the first epitaxial wafer to the second epitaxial wafer. The temperature for dry etching.
[0013] Furthermore, the temperature for growing the AlN layer is 1100℃~1300℃; the temperature for depositing the AlN seed layer is 300℃~500℃; the temperature for depositing the first SiO2 layer is 300℃~450℃; the temperature for depositing the bottom electrode is 300℃~400℃; the temperature for depositing the second SiO2 layer is 150℃~250℃; the temperature for bonding the first epitaxial wafer to the second epitaxial wafer is 25℃~150℃; and the temperature for dry etching is 15℃~50℃.
[0014] Further, the pressure for growing the AlN seed layer is less than the pressure for depositing the second SiO2 layer. The pressure for depositing the first SiO2 layer is less than the pressure for growing the AlN seed layer. The pressure for bonding the first epitaxial wafer to the second epitaxial wafer is less than the pressure for growing the AlN seed layer.
[0015] Furthermore, the pressure for growing the AlN seed layer is 1×10 -7 Torr ~7×10 -7 Torr; the pressure for depositing the second SiO2 layer is 1×10 -2 Torr ~1×10 -1 Torr; the pressure for depositing the first SiO2 layer is 1×10 - 1 Torr ~5×10 -1Torr; the pressure for growing the AlN layer is 40 Torr~60 Torr; the pressure for bonding the first epitaxial wafer and the second epitaxial wafer is 100 Torr~200 Torr.
[0016] Optionally, the organic solvent is chloroform or dichloromethane, which can remove the buffer layer quickly and completely.
[0017] In a fourth aspect, the present application provides a flexible substrate BAW device, which is manufactured by the flexible substrate BAW device manufacturing method described in the third aspect.
[0018] The beneficial effects of the present invention are as follows: the polyamine compound of the present invention can be used as a buffer layer when aluminum nitride is deposited on a hard substrate, and can alleviate the lattice mismatch and thermal mismatch between AlN and a foreign substrate. When a flexible substrate is needed to replace the hard substrate, the buffer layer can be simply washed away with an organic solvent, which facilitates separation of the hard substrate and the AlN piezoelectric film. The exposed AlN piezoelectric film has a higher quality surface, which is conducive to making the process of manufacturing a flexible substrate BAW device more efficient and high-quality.
[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic diagram of a method for preparing a flexible substrate BAW device provided in an embodiment of the present application.
[0021] Figure numerals: 10, hard substrate; 20, buffer layer; 30, AlN seed layer; 40, AlN layer; 50, bottom electrode; 60, first SiO2 layer; 70, flexible substrate; 80, second SiO2 layer; 90, top electrode. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0023] It should be understood that, under the premise of no conflict, any and all embodiments of the present invention can be combined with the technical features in any other embodiment or multiple other embodiments to obtain another embodiment. The present invention includes such a combination to obtain another embodiment.
[0024] In this specification, groups and substituents thereof can be selected by those skilled in the art to provide stable structural moieties and compounds. When substituents are described by conventional chemical formulas written from left to right, the substituents also include chemically equivalent substituents obtained when the structural formula is written from right to left.
[0025] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.
[0026] The buffer layer in the prior art makes the bonding force between AlN and the hard substrate extremely strong. When the hard substrate needs to be replaced with a flexible substrate, it is usually necessary to grind or cut the hard substrate and then perform chemical mechanical polishing to expose the aluminum nitride film. This process not only easily causes fine cracks in the epitaxial wafer, but also easily corrodes the side walls of the epitaxial wafer.
[0027] Reference Figure 1 The present invention provides a method for preparing a flexible substrate BAW device, comprising the following steps: S1: Spin-coating a polyamine compound solution on a hard substrate 10 to form a buffer layer 20; sequentially forming an AlN piezoelectric film, a bottom electrode 50, and a first SiO2 layer 60 on the buffer layer 20 to obtain a first epitaxial wafer.
[0028] S2: dry-etching the first SiO2 layer 60 on the first epitaxial wafer to form a groove in the center of the first SiO2 layer.
[0029] S3: depositing a second SiO2 layer 80 on the flexible substrate 70 to obtain a second epitaxial wafer.
[0030] S4: Bonding the first epitaxial wafer to the second epitaxial wafer with the first SiO2 layer 60 and the second SiO2 layer 80 facing each other so that the groove becomes a cavity to obtain a bonded epitaxial wafer.
[0031] S5: soaking the bonded epitaxial wafer in an organic solvent to dissolve the buffer layer 20 and peeling off the hard substrate 10 to expose the AlN piezoelectric film.
[0032] S6: Prepare a top electrode 90 on the AlN piezoelectric film to obtain a flexible substrate BAW device.
[0033] The AlN piezoelectric film may include an AlN seed layer 30 deposited on the buffer layer 20 and an AlN layer 40 grown on the AlN seed layer 30. Exposing the AlN piezoelectric film in step S5 specifically exposes the surface of the AlN seed layer 30. The thickness of the AlN seed layer may be 20nm-50nm, and the thickness of the AlN layer may be 1000nm-1500nm.
[0034] The solvent of the polyamine compound solution in step S1 is chloroform or dichloromethane, and the solute is a polyamine compound having a structure of formula D: ; Among them, R m , R n It is an amino group, a double bond, a triple bond, a hydrogen atom or a halogen atom.
[0035] The preparation steps of the compound are shown in reaction group 1: Reaction Group 1 The compound having the structure of formula A is dissolved in a solvent, and aqueous ammonia and a phase transfer catalyst are added, and the mixture is reacted at 0°C to 25°C for 8h to 24h. The reaction is stopped, and the mixture is cooled, filtered, and subjected to column chromatography to obtain a compound having the structure of formula B.
[0036] The compound having the structure of formula B is dissolved in a solvent, iodomethane and methanol are added, and the mixture is reacted at 25° C. to 50° C. for 12 h to 24 h. The reaction is stopped, and the mixture is cooled, filtered, and recrystallized to obtain a compound having the structure of formula C.
[0037] The compound having the structure of formula C is catalytically hydrogenated to obtain a compound having the structure of formula D.
[0038] The hard substrate may be a silicon substrate, a sapphire substrate, a silicon carbide substrate, a glass substrate, a gallium nitride substrate, an aluminum nitride substrate or a gallium oxide substrate.
[0039] The material of the flexible substrate can be silk or plastic, such as polyimide, polyparaxylene, polycarbonate, polyester resin, polyethylene naphthalate, polyethersulfone, polyetherimide, polydimethylsiloxane, polyvinyl alcohol or fluoropolymer.
[0040] The bottom electrode and the top electrode may be made of pure metal, alloy or arsenic-doped metal. The metal element is selected from gold, tungsten, molybdenum, platinum, ruthenium, iridium, germanium, copper, titanium, aluminum and chromium.
[0041] The organic solvent in step S5 may be chloroform or dichloromethane.
[0042] In order to protect the flexible deposition and buffer layers and to achieve the desired quality of each layer, an AlN seed layer is deposited on the buffer layer at a first temperature and a first pressure using PVD (physical vapor deposition).
[0043] An AlN layer is grown on the AlN seed layer at a second temperature and a second pressure by MOCVD (metal organic chemical vapor deposition).
[0044] A bottom electrode is deposited on the AlN layer at a third temperature using PVD.
[0045] A first SiO2 layer is deposited on the bottom electrode by PECVD (plasma enhanced chemical vapor deposition) at a fourth temperature and a third pressure.
[0046] A second SiO2 layer is deposited on the flexible substrate by PECVD at a fifth temperature and a fourth pressure.
[0047] The dry etching in step S2 is performed at a sixth temperature.
[0048] Step S4: bonding the two epitaxial wafers at the seventh temperature and the fifth pressure.
[0049] The second temperature is required to be greater than the first temperature, greater than the fourth temperature, greater than the third temperature, greater than the fifth temperature, greater than the seventh temperature, and greater than the sixth temperature. The first pressure is less than the fourth pressure, less than the third pressure, less than the second pressure, and less than the fifth pressure. This is beneficial to protecting the flexible substrate, and the buffer layer can still be dissolved by an organic solvent after the epitaxial wafer has been processed multiple times.
[0050] Specifically, the thickness of the AlN seed layer is 20nm to 50nm. The thickness of the AlN layer is 1000 nm to 1500 nm. The thickness of the bottom electrode is 1nm to 500nm. The thickness of the first SiO2 layer is 1000nm to 2000nm. The thickness of the second SiO2 layer is 500nm to 1000nm. The thickness of the top electrode is 1nm to 500nm. The growth temperature of the AlN seed layer is 300℃ to 500℃. The growth temperature of the AlN layer is 1100℃ to 1300℃. The growth temperature of the bottom electrode is 300℃ to 400℃. The growth temperature of the first SiO2 layer is 300℃ to 450℃. The growth temperature of the second SiO2 layer is 150℃ to 250℃. The etching temperature of the first SiO2 layer is 15℃ to 50℃. The bonding temperature of the first SiO2 and the second SiO2 layer is 25℃ to 150℃. The growth temperature of the top electrode is 300℃ to 400℃. The growth pressure of the AlN seed layer is 1×10 -7 Torr ~7×10 -7 Torr. The growth pressure of AlN layer is 40 Torr ~60 Torr. The growth pressure of bottom electrode is 1×10 -7 Torr ~7×10 -7 Torr. The growth pressure of the first SiO2 layer is 1×10 -1 Torr ~5×10 -1Torr. The pressure for depositing the second SiO2 layer is 1×10 -2 Torr ~1×10 -1 Torr. The bonding pressure between the first SiO2 layer and the second SiO2 layer is 100 Torr ~ 200 Torr. The growth pressure of the top electrode is 1×10 -7 Torr ~7×10 -7 Torr.
[0051] Example 1 The polyamine compounds are synthesized according to reaction formula 2.
[0052] Reaction Group 2 In a 250 mL round-bottom flask, 2-bromotriazine was dissolved in N,N'-dimethylformamide, and ammonia and a phase transfer catalyst were added, and stirred at 25°C for 10 h. The sample point plate was taken, and the heating was stopped when the reaction was complete. The reaction was quenched with a saturated NH4Cl solution, and extracted with dichloromethane three times. The organic phase was combined, dried with anhydrous Na2SO4, filtered, and the filtrate was spin-dried and separated by column chromatography to obtain the product 3-(1,3,5-triazinyl)amine, as shown in the structural formula B1 in reaction group 2.
[0053] Dissolve B1 in a solvent, add iodomethane, react at 30°C for 12 hours, stop the reaction, cool, filter, and recrystallize to obtain a 3-(1,3,5-triazine)amine methyl salt compound, such as structural formula C1 in reaction group 2.
[0054] C1 is placed in a 300° C. condition with a palladium catalyst and a nickel catalyst for catalytic hydrogenation to obtain a polyamine compound having a structural formula D1 as shown in reaction group 2.
[0055] The polyamine ring compound D1 was dissolved in dichloromethane, and the solution was dropped onto a sapphire substrate, and a buffer layer of the polyamine ring compound D1 was prepared by spin coating at a rotation speed of 4000 rpm.
[0056] The epitaxial wafer was transferred to a magnetron sputtering reaction chamber and 6×10 -7 A 50 nm AlN seed layer was deposited on the substrate at a pressure of 10 Torr.
[0057] The epitaxial wafer was transferred to the MOCVD reaction chamber, H2 and N2 were introduced into the reaction chamber, the temperature was raised to 1300°C, NH3 and Al sources were introduced, and the ratio of NH3 to Al sources was adjusted. The pressure in the reaction chamber was adjusted to 40 Torr, and an AlN layer was grown with a growth thickness of 1250nm.
[0058] The epitaxial wafer was transferred to a magnetron sputtering reaction chamber, and a 6×10-7 A 50 nm thick Mo electrode was deposited on the substrate under a pressure of 10 Torr as the bottom electrode.
[0059] The epitaxial wafer was transferred to the PECVD reaction chamber and -1 A first SiO2 layer of 2000 nm is deposited under a pressure of 0.1 torr. For ease of description, the epitaxial wafer at this time is referred to as the first epitaxial wafer.
[0060] The first epitaxial wafer with the first SiO2 layer is transferred into the reaction chamber, and a groove is etched at an etching temperature of 45°C.
[0061] Take a piece of flexible substrate and transfer it to the PECVD reaction chamber. -2 A second SiO2 layer of 500 nm is deposited under a pressure of Torr to obtain a second epitaxial wafer.
[0062] The first epitaxial wafer and the second epitaxial wafer are placed in a bonding machine and bonded at a temperature of 125° C. and a pressure of 150 Torr to form a bonded epitaxial wafer.
[0063] The bonded epitaxial wafer is placed in a dichloromethane solution to dissolve the buffer layer and peel off the sapphire substrate.
[0064] The bonded epitaxial wafer was transferred to a magnetron sputtering reaction chamber, and a 6×10 -7 A 50 nm Mo electrode was deposited on the substrate under a pressure of 10 Torr as the top electrode.
[0065] Example 2 The polyamine compounds are synthesized according to reaction formula 3.
[0066] Reaction Group 3 In a 250 mL round-bottom flask, 2-bromo-4,6-dimethyltriazine was dissolved in N,N'-dimethylformamide, and ammonia and a phase transfer catalyst were added, and stirred at 25°C for 12 hours. The sample point plate was taken, and the heating was stopped when the reaction was completely completed. The reaction was quenched with a saturated NH4Cl solution, and extracted with dichloromethane five times. The organic phase was combined, dried with anhydrous Na2SO4, filtered, and the filtrate was spin-dried and separated by column chromatography to obtain the product 3-(4,6-dimethyl-1,3,5-triazinyl)amine, as shown in the structural formula B2 in reaction group 3.
[0067] Dissolve B2 in a solvent, add iodomethane, react at 50°C for 24 hours, stop the reaction, cool, filter, and recrystallize to obtain a 3-(4,6-dimethyl-1,3,5-triazinyl)amine methyl salt compound, such as structural formula C2 in reaction group 3.
[0068] C2 is placed in a 400° C. condition with a palladium catalyst and a nickel catalyst for catalytic hydrogenation to obtain a polyamine compound having a structural formula D2 as shown in reaction group 3.
[0069] The polyamine ring compound D2 was dissolved in dichloromethane, and the solution was dropped onto a sapphire substrate, and a buffer layer of the polyamine ring compound D2 was prepared by spin coating at a rotation speed of 4000 rpm.
[0070] The epitaxial wafer was transferred to a magnetron sputtering reaction chamber and the epitaxial wafer was deposited at 7×10 -7 A 50 nm AlN seed layer was deposited on the substrate at a pressure of 10 Torr.
[0071] The epitaxial wafer was transferred to the MOCVD reaction chamber, H2 and N2 were introduced into the reaction chamber, the temperature was raised to 1200°C, NH3 and Al sources were introduced, and the ratio of NH3 to Al sources was adjusted. The pressure in the reaction chamber was adjusted to 45 Torr, and an AlN layer was grown with a growth thickness of 1250nm.
[0072] The epitaxial wafer was transferred to a magnetron sputtering reaction chamber, and the AlN layer was deposited by physical vapor deposition at a rate of 7×10 -7 A 55 nm Mo electrode was deposited on the substrate under a pressure of 10 Torr as the bottom electrode.
[0073] The epitaxial wafer was transferred to the PECVD reaction chamber and heated at 7×10 -1 A first SiO2 layer of 1500 nm is deposited under a pressure of 0.1 torr. For ease of description, the epitaxial wafer at this time is referred to as the first epitaxial wafer.
[0074] The first epitaxial wafer with the first SiO2 layer is transferred into the reaction chamber, and a groove is etched at an etching temperature of 45°C.
[0075] Take a piece of flexible substrate and transfer it to the PECVD reaction chamber. -2 A second SiO2 layer of 500 nm is deposited under a pressure of Torr to obtain a second epitaxial wafer.
[0076] The first epitaxial wafer and the second epitaxial wafer are placed in a bonding machine and bonded under the conditions of a temperature of 120° C. and a pressure of 140 Torr to form a bonded epitaxial wafer.
[0077] The bonded epitaxial wafer is placed in a dichloromethane solution to dissolve the buffer layer and peel off the sapphire substrate.
[0078] The bonded epitaxial wafer was transferred to a magnetron sputtering reaction chamber, and a 7×10 -7 A 40 nm Mo electrode was deposited on the substrate under a pressure of 10 Torr as the top electrode.
[0079] In the embodiment of the present application, a buffer layer is first formed by spin coating a polyamine compound on a hard substrate. Such compounds can effectively alleviate the lattice mismatch and thermal adaptation between the AlN film and the substrate. Subsequently, an AlN seed layer is deposited on the polyamine ring compound buffer layer by PVD, which can provide a good nucleation site for the subsequent growth of AlN. After that, an AlN layer with high crystal quality can be grown by MOCVD to form an aluminum nitride piezoelectric film. Then, the bottom electrode and the first SiO2 layer are deposited on the AlN piezoelectric film by PVD and PECVD methods. A second SiO2 layer is deposited on a flexible substrate by PECVD, and then a groove is etched on the first SiO2 layer by dry etching. The two substrates are non-metallic bonded, and then the polyamine compound is removed by an organic solvent such as dichloromethane and chloroform, and finally the top electrode is deposited on the AlN layer to complete the preparation of a flexible BAW device.
[0080] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0081] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A polyamine compound, characterized in that Having the structure of formula D: ； Among them, R m , R n It is an amino group, a double bond, a triple bond, a hydrogen atom or a halogen atom.
2. A method for preparing a polyamine compound, characterized in that: The method comprises the steps shown in reaction group 1: Reaction group 1; Dissolve the compound having the structure of formula A in a solvent, add ammonia water and a phase transfer catalyst, react at 0°C to 25°C for 8h to 24h, stop the reaction, cool, filter, and perform column chromatography to obtain a compound having the structure of formula B; Dissolve the compound having the structure of formula B in a solvent, add iodomethane, react at 25°C to 50°C for 12h to 24h, stop the reaction, cool, filter, and recrystallize to obtain a compound having the structure of formula C; Catalytically hydrogenating a compound having a structure of Formula C to obtain a compound having a structure of Formula D; Among them, R m , R n It is an amino group, a double bond, a triple bond, a hydrogen atom or a halogen atom.
3. A method for preparing a flexible substrate BAW device, characterized in that: The following steps are involved: Spin-coating a polyamine compound solution on a hard substrate to form a buffer layer, wherein the solute of the polyamine compound solution is the polyamine compound according to claim 1; sequentially forming an AlN piezoelectric film, a bottom electrode, and a first SiO2 layer on the buffer layer to obtain a first epitaxial wafer; dry-etching the first SiO2 layer on the first epitaxial wafer to form a groove in the center of the first SiO2 layer; Depositing a second SiO2 layer on the flexible substrate to obtain a second epitaxial wafer; Bonding the first epitaxial wafer to the second epitaxial wafer with the first SiO2 layer facing the second SiO2 layer so that the groove becomes a cavity to obtain a bonded epitaxial wafer; Soaking the bonded epitaxial wafer in an organic solvent to dissolve the buffer layer, and peeling off the hard substrate to expose the AlN piezoelectric film; A top electrode is prepared on the AlN piezoelectric film to obtain the flexible substrate BAW device.
4. The method for preparing a flexible substrate BAW device according to claim 3, characterized in that: The step of sequentially forming an AlN piezoelectric film, a bottom electrode, and a first SiO2 layer on the buffer layer comprises: Depositing an AlN seed layer on the buffer layer by PVD; Growing an AlN layer on the AlN seed layer by MOCVD; the AlN seed layer and the AlN layer constitute the AlN piezoelectric film; Depositing the bottom electrode on the AlN layer by PVD; Depositing the first SiO2 layer on the bottom electrode by PECVD; The step of depositing a second SiO2 layer on the flexible substrate comprises: A second SiO2 layer was deposited on the flexible substrate using PECVD.
5. The method for preparing a flexible substrate BAW device according to claim 4, characterized in that: The temperature for growing the AlN layer>the temperature for depositing the AlN seed layer>the temperature for depositing the first SiO2 layer>the temperature for depositing the bottom electrode>the temperature for depositing the second SiO2 layer>the temperature for bonding the first epitaxial wafer to the second epitaxial wafer>the temperature for dry etching.
6. The method for preparing a flexible substrate BAW device according to claim 5, characterized in that: The temperature for growing the AlN layer is 1100°C to 1300°C; the temperature for depositing the AlN seed layer is 300°C to 500°C; the temperature for depositing the first SiO2 layer is 300°C to 450°C; the temperature for depositing the bottom electrode is 300°C to 400°C; The temperature for depositing the second SiO2 layer is 150°C to 250°C; the temperature for bonding the first epitaxial wafer to the second epitaxial wafer is 25°C to 150°C; and the temperature for dry etching is 15°C to 50°C.
7. The method for preparing a flexible substrate BAW device according to claim 4, characterized in that: The pressure for growing the AlN seed layer is less than the pressure for depositing the second SiO2 layer. The pressure for depositing the first SiO2 layer is less than the pressure for growing the AlN layer. The pressure for bonding the first epitaxial wafer to the second epitaxial wafer is less than the pressure for growing the AlN layer.
8. The method for preparing a flexible substrate BAW device according to claim 7, characterized in that: The pressure for growing the AlN seed layer is 1×10 -7 Torr ~7×10 -7 Torr; the pressure for depositing the second SiO2 layer is 1×10 -2 Torr ~1×10 -1 Torr; the pressure for depositing the first SiO2 layer is 1×10 -1 Torr ~5×10 -1 Torr; the pressure for growing the AlN layer is 40 Torr~60 Torr; the pressure for bonding the first epitaxial wafer and the second epitaxial wafer is 100 Torr~200 Torr.
9. The method for preparing a flexible substrate BAW device according to claim 3, characterized in that: The organic solvent is chloroform or dichloromethane.
10. A flexible substrate BAW device, characterized in that: The device is manufactured by the method for manufacturing a flexible substrate BAW device according to any one of claims 3 to 9.