Filter device preparation method and filter device

Abstract

The embodiment of the invention provides a filter device preparation method and a filter device, and relates to the technical field of semiconductors, and the filter device preparation method comprises the steps: preparing a composite wafer; obtaining and judging whether the thickness distribution of the substrate layer on the surface of the composite wafer meets a preset standard or not; when the thickness distribution does not accord with the preset standard, a filter metal electrode interdigital is prepared on the surface of the composite wafer according to the thickness distribution, and fluctuation defects caused by the thickness distribution of the piezoelectric layer on the surface of the composite wafer at the corresponding position are compensated through the width of the filter metal electrode interdigital; and the frequencies of all areas of the filter device are kept consistent. Based on this, the dynamic compensation of photoetching exposure is realized by quantifying the relevance between the film thickness surface type distribution and the frequency deviation, the photoetching exposure is accurately regulated and controlled in a partitioned manner, the adaptation capability of the traditional exposure compensation method to the film thickness space distribution is made up, and the consistency of the bonding wafer film thickness surface type distribution is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more particularly, to a method for preparing a filtering device and a filtering device. Background Art

[0002] In the field of semiconductor manufacturing, the film thickness uniformity of bonded wafers is closely related to the performance of filtering devices, such as the frequency of filters. To improve the performance of filtering devices, for example, to keep the frequency performance of the devices consistent, it is usually required to keep the thickness of the substrate film on the surface of the bonded wafer highly consistent. However, due to differences in raw materials, fluctuations in the bonding process, or errors in thinning and polishing, there are significant non-uniformities in the actual film thickness surface profile distribution (such as concentric circles, eccentric circles, etc.) obtained during preparation. This non-uniformity leads to discrete frequency distribution and poor consistency of the filtering devices after lithography, directly resulting in a low device yield.

[0003] To overcome the above technical problems, usually, technicians will improve the film thickness uniformity by modifying the parameters of the bonding process or the thinning and polishing process. However, this method is limited by the equipment accuracy and raw material characteristics and is difficult to completely eliminate process fluctuations. Although the prior art improves the above problems by performing overall exposure compensation on the bonded wafers, the accuracy of the exposure compensation during the overall exposure compensation process is limited by the working state and conditions of the machine on the day.

[0004] Based on this, there is an urgent need for a solution to improve the film thickness surface profile distribution of bonded wafers, which can make up for the lack of adaptability to the spatial distribution of film thickness in traditional exposure compensation methods and improve the frequency consistency of filtering devices. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for preparing a filtering device and a filtering device, which realizes dynamic compensation of lithography exposure by quantifying the correlation between the film thickness surface profile distribution and the frequency deviation, so as to accurately control the lithography exposure amount in zones and improve the consistency of the film thickness surface profile distribution of bonded wafers.

[0006] To achieve the above purpose, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, the present invention provides a method for preparing a filtering device, and the method for preparing the filtering device includes the following steps: Prepare a composite wafer; Obtain and determine whether the thickness distribution of the substrate layer on the surface of the composite wafer meets a preset standard; When it does not meet the preset standard, according to the thickness distribution, prepare filtering device metal electrode fingers on the surface of the composite wafer, and compensate for the fluctuation defects of the substrate layer at the corresponding positions through the width of the filtering device metal electrode fingers, so that the frequency distributions of the filtering devices corresponding to each region on the composite wafer are kept consistent; wherein, the fluctuation defects are caused by the thickness distribution.

[0007] Optionally, when preparing the interdigital metal electrodes of the filter device by the development exposure method using an exposure and development device, and the exposure and development device includes an independent exposure unit, and each region on the composite wafer corresponds to an initial exposure amount, the steps of preparing an interdigital metal electrode of a filter device on the surface of the composite wafer according to the thickness distribution include: Determine the exposure compensation amount corresponding to each region on the composite wafer according to the thickness distribution to obtain the exposure compensation amount distribution; Correspondingly adjust the initial exposure amount of the independent exposure unit in the current region using the exposure compensation amount distribution to obtain the target exposure amount corresponding to each region; The independent exposure unit traverses the composite wafer according to the target exposure amount corresponding to each region to obtain the composite wafer after lithography processing; Process the composite wafer after lithography processing using a coating and stripping process to obtain the interdigital metal electrodes of the filter device; Among them, the width of the interdigital metal electrodes of the filter device corresponding to each region has a mapping relationship with the thickness distribution.

[0008] Optionally, the steps of obtaining and determining whether the thickness distribution of the substrate layer on the surface of the composite wafer meets the preset standard include: Traverse the film thickness values corresponding to each region on the substrate layer on the surface of the composite wafer to obtain the thickness distribution of the substrate layer on the surface of the composite wafer; Determine the difference between the film thickness value corresponding to each region and the preset value; Judge whether each difference is less than or equal to the preset value to evaluate whether the thickness distribution of the substrate layer on the surface of the composite wafer meets the preset standard.

[0009] Optionally, the steps of correspondingly adjusting the initial exposure amount of the current independent exposure unit using the exposure compensation amount distribution to determine the target exposure amount include: Obtain the first weight, the second weight, and the third weight respectively; among them, the first weight is used to characterize the mapping coefficient between the film thickness change amount and the device frequency change amount; the second weight is used to characterize the mapping coefficient between the electrode width change amount corresponding to each region and the device frequency change amount; the third weight is used to characterize the mapping coefficient between the exposure amount change amount and the corresponding electrode width change amount; Determine the change amount of the device frequency at any region according to the difference between the film thickness value corresponding to each region and the preset value and the first weight; For any region, determine the width adjustment amount of the interdigital metal electrodes of the filter device corresponding to the current region according to the change amount of the device frequency and the second weight; Determine the exposure adjustment amount of the independent exposure unit in the current region according to the width adjustment amount and the third weight; Adjust the initial exposure amount of the independent exposure unit in the current region according to the exposure adjustment amount to obtain the corresponding target exposure amount.

[0010] Optionally, the calculation formula for determining the change amount of the device frequency at any region is expressed as: Δf = a * Δh; Wherein, Δf is the change amount of the device frequency at any region; Δh is the difference between the corresponding film thickness value and the preset value at any region; a is the first weight.

[0011] Optionally, the calculation formula for determining the width adjustment amount of the interdigital fingers of the metal electrode of the filter device corresponding to the current region is expressed as: Δf = b * Δw; Wherein, Δf is the change amount of the device frequency at any region; Δw is the width adjustment amount of the interdigital fingers of the metal electrode of the filter device at the current regions; b is the second weight.

[0012] Optionally, the calculation formula for determining the exposure adjustment amount of the independent exposure unit under the current region is expressed as: ΔE = c * Δw; Wherein, ΔE is the exposure adjustment amount of any independent exposure unit; Δw is the width adjustment amount of the interdigital fingers of the metal electrode of the filter device at the current region; c is the third weight.

[0013] Optionally, the calculation formula for adjusting the initial exposure amount of the independent exposure unit under the current region according to the exposure adjustment amount to obtain the corresponding target exposure amount is expressed as: E i = ΔE i + E i0 ; Wherein, E i is the target exposure amount of the independent exposure unit at the i-th region; ΔE i is the corresponding exposure adjustment amount at the i-th region; E i0 is the initial exposure amount of the independent exposure unit at the i-th region.

[0014] Optionally, the steps of preparing a composite wafer include: Providing at least two wafers; wherein, at least two wafers include a target wafer, the target wafer serves as the upper wafer substrate layer, and the bottom of the other wafers except the target wafer serves as the lower wafer support substrate layer; Bonding at least two wafers to obtain an initial composite wafer; Thinning and chemical mechanical polishing the upper wafer substrate layer of the initial composite wafer to obtain the final composite wafer.

[0015] In a second aspect, the present invention further provides a filter device, and the filter device is prepared by the filter device preparation method provided in the first aspect above.

[0016] The method for preparing a filtering device and the filtering device provided by the embodiments of the present invention have the following beneficial effects: The method for preparing a filtering device in the present invention includes: preparing a composite wafer; obtaining and determining whether the thickness distribution of the substrate layer on the surface of the composite wafer meets a preset standard; when it does not meet the preset standard, a filtering device metal electrode finger is prepared on the surface of the composite wafer according to the thickness distribution, and the width of the filtering device metal electrode finger is used to compensate for the fluctuation defects caused by the uneven thickness distribution of the piezoelectric layer on the substrate layer at the corresponding position, so that the frequencies of all regions of the filtering device are consistent. Based on this, the present invention realizes dynamic compensation of lithographic exposure by quantifying the correlation between the film thickness surface profile distribution and the frequency deviation, so as to accurately control the lithographic exposure amount in different regions and improve the consistency of the film thickness surface profile distribution of the bonded wafer.

[0017] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, makes a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 Shows the step flowchart of the method for preparing a filtering device provided by the embodiments of the present invention; Figure 2 Shows the sub-step flowchart of step 100 in the embodiments of the present invention; Figure 3 Shows the sub-step flowchart of step 200 in the embodiments of the present invention; Figure 4 Shows the sub-step flowchart of step 300 in the embodiments of the present invention; Figure 5 Shows the schematic diagram of preparing the filtering device metal electrode finger in the embodiments of the present invention; Figure 6 Shows the sub-step flowchart of step 302 in the embodiments of the present invention; Figure 7 Shows the first electrical performance test result in this embodiment; Figure 8 Shows the second electrical performance test result in this embodiment; Figure 9 Shows the third electrical performance test result in this embodiment; Figure 10Shows the film thickness of the bonding wafer substrate layer before exposure amount adjustment in this embodiment; Figure 11 Shows the exposure distribution map after exposure amount adjustment in this embodiment; Figure 12 Shows the frequency distribution corresponding to the filter device prepared based on the adjusted exposure amount in this embodiment. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0022] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0023] To avoid the problems of discrete frequency distribution and poor consistency of the filter device after lithography caused by the film thickness surface profile distribution, the present invention provides a solution for improving the film thickness surface profile distribution of the bonding wafer, which can improve the frequency consistency of the filter device by compensating for the lack of adaptability to the spatial distribution of the film thickness in the traditional exposure compensation method.

[0024] In the first aspect, please refer to Figure 1 , Figure 1 Shows a step flowchart of a method for manufacturing a filter device, and the method for manufacturing the filter device includes steps 100 to 300.

[0025] Step 100: Prepare a composite wafer.

[0026] Step 200: Obtain and determine whether the thickness distribution of the substrate layer on the surface of the composite wafer meets the preset standard.

[0027] Step 300: When it does not meet the preset standard, according to the thickness distribution, prepare the interdigital metal electrodes of the filtering device on the surface of the composite wafer, and compensate for the fluctuation defects of the substrate layer at the corresponding positions by the width of the interdigital metal electrodes of the filtering device, so that the frequency distributions of the filtering devices corresponding to each region on the composite wafer are kept consistent.

[0028] Among them, the fluctuation defects are caused by the thickness distribution.

[0029] In this embodiment, the thickness distribution of the substrate layer on the surface of the prepared composite wafer can be monitored in real time. When it is monitored that the thickness distribution does not meet the preset standard, the interdigital metal electrodes of the filtering device are prepared on the surface of the composite wafer according to the monitored thickness distribution of the surface substrate layer. By adjusting the width of the interdigital metal electrodes of the filtering device, the fluctuation defects of the substrate layer film thickness distribution at the corresponding positions are compensated, so that the frequency distributions of the filtering devices prepared in each region of the whole composite wafer are kept consistent.

[0030] Based on this, in this embodiment, the thickness distribution of the substrate layer on the surface of the composite wafer is compensated by the width of the interdigital metal electrodes of the filtering device, thereby improving the frequency consistency and yield of the filtering device.

[0031] In a possible implementation manner, in this embodiment, the mapping relationship between the thickness distribution, the device frequency, and the exposure amount for preparing the interdigital metal electrodes of the filtering device can be established. Then, according to this mapping relationship, the photolithography exposure amount is accurately regulated in zones, so as to achieve the purpose of compensating the thickness distribution of the substrate layer on the surface of the composite wafer by the width of the interdigital metal electrodes of the filtering device, and making the frequency distributions of the filtering devices prepared in each region of the whole composite wafer consistent.

[0032] Please refer to Figure 2 , Figure 2 which shows the sub-step flowchart of Step 100 in this embodiment. The step 100 of preparing the composite wafer includes steps 101 to 103.

[0033] Step 101: Provide at least two wafers; among them, at least two wafers include a target wafer, and the target wafer serves as the upper wafer substrate layer, and the bottoms of the other wafers except the target wafer serve as the lower wafer support substrate layer.

[0034] Step 102: Bond the at least two wafers to obtain an initial composite wafer.

[0035] Step 103: Thin and perform chemical mechanical polishing on the upper wafer substrate layer of the initial composite wafer to obtain the final composite wafer.

[0036] In this embodiment, when the composite wafer includes two wafers, the lithium tantalate wafer can be used as the upper wafer substrate layer, and the silicon wafer can be used as the lower wafer support substrate layer. Among them, the wafer thickness of the lithium tantalate wafer satisfies: 250μm - 350μm; the total thickness variation TTV of the wafer corresponding to the wafer polished surface is less than 3μm, and the profile arithmetic average deviation Ra is less than 0.3nm. In this embodiment, the wafer thickness of the silicon wafer satisfies 350μm - 700μm. When the wafer thickness of the silicon wafer in this embodiment can be 500μm, correspondingly, the total thickness variation TTV of the wafer is less than 1.5μm, and the profile arithmetic average deviation Ra is less than 0.2nm.

[0037] Then, room-temperature surface activation bonding is performed on the selected wafers. In this embodiment, the set conditions for room-temperature surface activation bonding can meet: The bonding environment needs to be in a high-vacuum state of 10 -6 Pa, the irradiation gas can be argon Ar, the irradiation activation time is 30s - 100s, the bonding pressure is 1000 - 10000N, and the crimping time is 10s - 50s.

[0038] Subsequently, mechanical grinding and CMP chemical mechanical polishing can be performed on the upper lithium tantalate layer of the bonded composite wafer to obtain a two-layer composite wafer. The target thickness of the surface lithium tantalate of this composite wafer is equal to 15μm. It should be noted that the composite wafer can determine different surface materials and corresponding thicknesses according to the simulation data corresponding to the actual situation.

[0039] On this basis, the step of obtaining and judging whether the thickness distribution of the surface substrate layer of the composite wafer in step 200 meets the preset standard can be: Equipment such as an ellipsometer or an infrared interferometer can be used to divide different regions in a matrix manner, and then the thickness distribution of the surface lithium tantalate of a single composite wafer can be obtained; then it is judged whether the thickness distribution meets the preset thickness distribution.

[0040] For example, when the target thickness of lithium tantalate satisfies 15μm, it can be judged whether the film thickness range corresponding to the thickness distribution is less than 0.5μm. If it is less, no compensation is required. If the film thickness range is greater than 0.5μm, compensation is required.

[0041] In this embodiment, a filter device metal electrode finger can be prepared by a development exposure method using an exposure and development device. The exposure and development device includes an independent exposure unit. The independent exposure unit corresponds to an initial exposure amount in each region and traverses the entire composite wafer in a step-by-step manner.

[0042] At this time, please refer to Figure 3 , Figure 3The sub-step flowchart of step 200 in this embodiment is shown. Step 200 of obtaining and determining whether the thickness distribution of the surface substrate layer of the composite wafer meets the preset standard includes steps 201 to 203.

[0043] Step 201, traverse the film thickness values corresponding to each region on the surface substrate layer of the composite wafer to obtain the thickness distribution of the surface substrate layer of the composite wafer.

[0044] Step 202, determine the difference between the film thickness value corresponding to each region and the preset value.

[0045] Step 203, judge whether each difference is less than or equal to the preset value to evaluate whether the thickness distribution of the surface substrate layer of the composite wafer meets the preset standard.

[0046] If not, please refer to Figure 4 , Figure 4 The sub-step flowchart of step 300 in this embodiment is shown. Step 300 of fabricating a filter device metal electrode finger on the surface of the composite wafer according to the thickness distribution includes steps 301 to 304.

[0047] Step 301, determine the exposure compensation amount corresponding to each region on the surface of the composite wafer according to the thickness distribution to obtain the exposure compensation amount distribution.

[0048] Step 302, use the exposure compensation amount distribution to correspondingly adjust the initial exposure amount of the independent exposure unit in the current region to obtain the target exposure amount corresponding to each region.

[0049] Step 303, use the independent exposure unit to traverse the composite wafer according to the target exposure amount corresponding to each region to obtain the composite wafer after lithography processing.

[0050] Step 304, use the coating stripping process to process the composite wafer after lithography processing to obtain the filter device metal electrode finger.

[0051] Among them, the width of the filter device metal electrode finger corresponding to each region has a mapping relationship with the thickness distribution.

[0052] In this embodiment, the steps of fabricating the filter device metal electrode finger by using the exposure and development equipment with the development exposure method are as follows: Please refer to Figure 5 , Figure 5 The schematic diagram of fabricating the filter device metal electrode finger in this embodiment is shown; among them, Si is used to represent the silicon wafer, LT is used to represent the lithium tantalate wafer; IDT is used to represent the filter device metal electrode finger; h is used to represent the thickness of the lithium tantalate wafer; W is used to represent the width of the filter device metal electrode finger.

[0053] Specifically, a photoresist with a certain thickness is coated on one side of the composite wafer substrate layer (the surface of the lithium tantalate wafer), and step-by-step exposure is performed according to a preset and fixed exposure amount E (i.e., the target exposure amount described in this application, which is determined by correspondingly adjusting the initial exposure amount of the current independent exposure unit through the exposure compensation amount distribution). Then, through the developing process, a solidified strip structure of the photoresist is obtained. Then, a metal film layer is formed by physical vapor deposition. The metal is usually pure aluminum or aluminum-copper alloy, etc. Then, the photoresist strip and the metal on the photoresist strip are removed by physical stripping, and a complete interdigital metal electrode of the filtering device is obtained on the surface of the substrate layer.

[0054] Please refer to Figure 6 , Figure 6 which shows the sub-step flowchart of step 302 in this embodiment. Step 302 in this embodiment includes steps 3021 to 3025.

[0055] Step 3021: Obtain the first weight, the second weight, and the third weight respectively.

[0056] Among them, the first weight is used to characterize the mapping coefficient between the film thickness change amount and the device frequency change amount; the second weight is used to characterize the mapping coefficient between the corresponding electrode width change amount in each region and the device frequency change amount; the third weight is used to characterize the mapping coefficient between the exposure amount change amount and the corresponding electrode width change amount.

[0057] Step 3022: Determine the change amount of the device frequency at any region according to the difference between the film layer thickness value corresponding to each region and the preset value and the first weight.

[0058] Step 3023: For any region, determine the width adjustment amount of the interdigital metal electrode of the corresponding filtering device in the current region according to the change amount of the device frequency and the second weight.

[0059] Step 3024: Determine the exposure adjustment amount of the independent exposure unit corresponding to the current region according to the width adjustment amount and the third weight.

[0060] Step 3025: Adjust the initial exposure amount of the independent exposure unit in the current region according to the exposure adjustment amount to obtain the corresponding target exposure amount.

[0061] In this embodiment, the electrode width change amount is the width change amount of the metal electrode fingers.

[0062] In a possible way, the wafer prepared above can be used for electrical performance testing in this embodiment, so as to determine the relationship between the thickness of the piezoelectric layer on the surface layer of the current composite wafer and the device frequency, and then determine the first weight.

[0063] For example, please refer to Figure 7 , Figure 7Shows the first electrical performance test results in this embodiment. Among them, the abscissa is the current bonded wafer lithium tantalate substrate layer film thickness table; the ordinate is the frequency of the filtering device. It can be seen that within a certain bonded substrate layer film thickness range, when the film layer becomes thinner, the device frequency increases, and when the film layer becomes thicker, the device frequency decreases. When the film thickness range is 1.34μm, the device frequency range obtained under the condition of fixed exposure amount is 2.8MHz, and the frequency range distribution is about 1520ppm.

[0064] Among them, R 2 The percentage of the variance of the dependent variable jointly explained by the independent variables, and its value ranges between 0 and 100%. In this embodiment, the percentage R of the variance of the dependent variable jointly explained by the independent variables under the first electrical performance test results 2 can reach 0.9875. A higher R 2 value means that the model can better explain the variation of the dependent variable. In this embodiment, a change in the 1μm substrate layer film thickness corresponds to a frequency change of about 2.09MHz. Based on this, the first weight can be equal to -2.09.

[0065] Similarly, the performance of the structured wafers prepared under different exposure amount conditions can be tested to obtain the average value of the frequency data of each wafer, so as to determine the relationship between the exposure amount and the device frequency, and then obtain the second weight.

[0066] For example, reference can be made to Figure 8 , Figure 8 Shows the second electrical performance test results in this embodiment. The abscissa is the exposure amount, and the ordinate is the frequency of the filtering device. Within a certain exposure amount range, when the exposure amount increases, the interdigital fingers of the metal electrodes of the final device become wider and the device frequency decreases. When the exposure amount decreases, the interdigital fingers of the metal electrodes of the final device become narrower and the device frequency increases. The percentage R of the variance of the dependent variable jointly explained by the independent variables of this linear fitting 2 is equal to 0.9231, indicating that this linear fitting model can better explain the variation of the dependent variable. In this embodiment, with 600nm as the reference, for every 25nm change in the width of the metal finger bars, the corresponding frequency changes by about 1MHz. Based on this, the second weight can be equal to -1 / 25.

[0067] Based on this, in this embodiment, the weight coefficients obtained by fitting the first electrical performance test results and the second electrical performance test results are used. Then, by establishing the mapping relationship between the thickness distribution, the device frequency and the exposure amount for preparing the interdigital fingers of the metal electrodes of the filtering device, when the matrix distribution of the known film thickness is known, by adjusting the exposure amount of the exposure unit at the corresponding point, differential frequency control is realized, and the frequency distribution of the devices on a single wafer is optimized. For example, in the area where the film layer is relatively thick, the corresponding exposure amount needs to be reduced; in the area where the film layer is relatively thin, the corresponding exposure amount needs to be increased; and then the change in frequency is compensated to achieve the purpose of frequency modulation and improve the performance yield of the device.

[0068] Specifically, after determining the change in device frequency corresponding to each region based on the difference between the film layer thickness value corresponding to each region and the preset value and the first weight, the change in device frequency at any region can be used as the deviation compensation requirement for the interdigital fingers of the metal electrode of the filter device corresponding to the current region, and then the size adjustment amount required for the interdigital fingers of the metal electrode obtained after the negative photoresist lithography coating stripping process for the corresponding device can be determined, that is, the above-mentioned width adjustment amount.

[0069] In this embodiment, taking 600 nm as the reference benchmark, for every 1 mj / cm change in the exposure dose, 2 the interdigital fingers of the metal electrode change by approximately 10 nm. Based on this, the third weight can be equal to 10.

[0070] In this embodiment, the calculation formula for determining the change in device frequency at any region is expressed as: Δf = a * Δh; In the formula, Δf is the change in device frequency at any region; Δh is the difference between the film layer thickness value corresponding to the current region and the preset value; a is the first weight.

[0071] In this embodiment, the calculation formula for determining the width adjustment amount of the interdigital fingers of the metal electrode of the filter device corresponding to the current region is expressed as: Δf = b * Δw; In the formula, Δf is the change in device frequency at any region; Δw is the width adjustment amount of the interdigital fingers of the metal electrode of the filter device corresponding to the current region; b is the second weight.

[0072] After obtaining the width adjustment amount, the width adjustment amount can be used as the deviation compensation requirement for the exposure dose, and then the exposure dose corresponding to each exposure unit during the exposure operation can be adjusted.

[0073] In this embodiment, the calculation formula for determining the exposure adjustment amount of the independent exposure unit in the current region is expressed as: ΔE = c * Δw; In the formula, ΔE is the exposure adjustment amount of any independent exposure unit; Δw is the width adjustment amount of the interdigital fingers of the metal electrode of the filter device corresponding to the current region; c is the third weight.

[0074] In this embodiment, the mapping coefficient between the change in exposure dose and the corresponding change in electrode width can be obtained by fitting through a normal lithography process.

[0075] Among them, the calculation formula for obtaining the corresponding target exposure dose by adjusting the initial exposure dose of the independent exposure unit in the current region according to the exposure adjustment amount is expressed as: E i = ΔE i + E i0 ; In the formula, E iis the target exposure amount of the independent exposure unit at the i-th area; ΔE i is the corresponding exposure adjustment amount at the i-th area; E i0 is the initial exposure amount of the independent exposure unit at the i-th area.

[0076] In summary, by establishing the mapping relationship among the thickness distribution, device frequency, and exposure amount of the metal electrode fingers of the fabricated filter device, and then precisely regulating the lithography exposure amount by region, the present application realizes the refined management of the production process. At the same time, it effectively compensates for the frequency deviation of the product device caused by the inconsistent film thickness of the bonding wafer substrate layer, making the frequencies of the filter devices obtained after one lithography more concentrated, the consistency significantly improved, directly reducing the number of unqualified products, increasing the yield rate of the product, reducing the production cost, and enhancing the product competitiveness.

[0077] In a second aspect, the present invention also provides a filter device, which is prepared by the filter device preparation method provided in the first aspect above.

[0078] In addition, please refer to Figure 9 , Figure 9 , which shows the electrical performance test results obtained by performing electrical performance tests on the filter device in this embodiment. The wafer-level test sets the test areas in the same matrix manner as the above-mentioned Figure 7 , Figure 8 corresponding electrical performance tests. The requirements for each test area are corresponding to the film thickness test and the position of the exposure unit. Multiple sets of data of film thickness and frequency corresponding to 2X2 matrices are selected at different positions on the wafer. Among them, after scatter plotting and fitting, a new correlation function relationship between the film thickness of the bonding wafer lithium tantalate substrate layer and the frequency can be obtained: Y = -0.0195x + 920.55; Y is the device frequency, X is the film thickness of the bonding wafer lithium tantalate substrate layer. At this time, the coefficient before the film thickness is extremely small, and R 2 = 0.006, indicating that the device frequency after exposure amount adjustment is more stable and no longer changes significantly with the change of film thickness.

[0079] At the same time, please refer to Figure 10 , Figure 11 , Figure 12 , Figure 10 is the film thickness of the bonding wafer substrate layer before exposure amount adjustment, Figure 11 is the exposure distribution map after exposure amount adjustment, Figure 12 is the frequency distribution corresponding to the filter device prepared based on the exposure amount adjustment; it can be seen that the device frequency distribution after dynamic adjustment of the exposure amount is more concentrated, and the frequency standard deviation is increased to 0.15.

[0080] In summary, the present invention realizes dynamic compensation for lithographic exposure by quantifying the correlation between the film thickness surface profile distribution and the frequency deviation, so as to accurately regulate the lithographic exposure amount in zones and improve the consistency of the film thickness surface profile distribution of the bonded wafers.

[0081] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0082] In addition, in each embodiment of the present invention, the functional modules can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0083] If the described function is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disks, or optical discs that can store program code.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a filtering device, characterized in that, The method for preparing the filtering device includes the following steps: Prepare a composite wafer; Obtain and determine whether the thickness distribution of the substrate layer on the surface of the composite wafer meets a preset standard; When it does not meet the preset standard, according to the thickness distribution, prepare the interdigital filtering device metal electrodes on the surface of the composite wafer, and compensate for the fluctuation defects of the substrate layer at the corresponding positions through the widths of the interdigital filtering device metal electrodes, so that the frequency distributions of the filtering devices corresponding to each area on the composite wafer are kept consistent; wherein, the fluctuation defects are caused by the thickness distribution.

2. The method for preparing a filtering device according to claim 1, wherein When preparing the interdigital filtering device metal electrodes by using the development exposure method through an exposure and development device, and the exposure and development device includes an independent exposure unit, and each area on the composite wafer corresponds to an initial exposure amount, the step of preparing an interdigital filtering device metal electrode on the surface of the composite wafer according to the thickness distribution includes: Determine the exposure compensation amount corresponding to each area on the composite wafer according to the thickness distribution to obtain an exposure compensation amount distribution; Correspondingly adjust the initial exposure amount of the independent exposure unit in the current area by using the exposure compensation amount distribution to obtain the target exposure amount corresponding to each area; Traverse the composite wafer by using the independent exposure unit according to the target exposure amount corresponding to each area to obtain a composite wafer after lithography processing; Process the composite wafer after lithography processing by using a coating and stripping process to obtain the interdigital filtering device metal electrodes; Wherein, the widths of the interdigital filtering device metal electrodes corresponding to each area have a mapping relationship with the thickness distribution.

3. The method for manufacturing a filtering device according to claim 2, wherein, The step of obtaining and determining whether the thickness distribution of the substrate layer on the surface of the composite wafer meets a preset standard includes: Traverse the film thickness values corresponding to each area on the substrate layer on the surface of the composite wafer to obtain the thickness distribution of the substrate layer on the surface of the composite wafer; Determine the difference between the film thickness value corresponding to each area and a preset value; Judge whether each difference is less than or equal to the preset value to evaluate whether the thickness distribution of the substrate layer on the surface of the composite wafer meets the preset standard.

4. The method for preparing a filtering device according to claim 3, wherein The step of correspondingly adjusting the initial exposure amount of the current independent exposure unit by using the exposure compensation amount distribution to obtain the target exposure amount corresponding to each area includes: Respectively obtain a first weight, a second weight and a third weight; wherein, the first weight is used to characterize the mapping coefficient between the film thickness change amount and the device frequency change amount; the second weight is used to characterize the mapping coefficient between the corresponding electrode width change amount at each area and the device frequency change amount; the third weight is used to characterize the mapping coefficient between the exposure amount change amount and the corresponding electrode width change amount; Determine the change amount of the device frequency at any area according to the difference between the film thickness value corresponding to each area and the preset value and the first weight; For any area, determine the width adjustment amount of the corresponding interdigital filtering device metal electrode at the current area according to the change amount of the device frequency and the second weight; Determine the exposure adjustment amount of the independent exposure unit in the current area according to the width adjustment amount and the third weight; Adjust the initial exposure amount of the independent exposure unit in the current area according to the exposure adjustment amount to obtain the corresponding target exposure amount.

5. The method for preparing a filtering device according to claim 4, characterized in that, The calculation formula for determining the change in the device frequency at any region is expressed as: Δf = a * Δh; In the formula, Δf is the change in the device frequency at any region; Δh is the difference between the film thickness value corresponding to the current region and the preset value; a is the first weight.

6. The method for manufacturing a filtering device according to claim 4, wherein, The calculation formula for determining the adjustment amount of the width of the interdigital fingers of the metal electrode of the filtering device corresponding to the current region is expressed as: Δf = b * Δw; In the formula, Δf is the change in the device frequency at any region; Δw is the adjustment amount of the width of the interdigital fingers of the metal electrode of the filtering device corresponding to the current region; b is the second weight.

7. The method for preparing a filtering device according to claim 4, wherein The calculation formula for determining the exposure adjustment amount of the independent exposure unit in the current region is expressed as: ΔE = c * Δw; In the formula, ΔE is the exposure adjustment amount of any independent exposure unit; Δw is the adjustment amount of the width of the interdigital fingers of the metal electrode of the filtering device corresponding to the current region; c is the third weight.

8. The method for preparing a filtering device according to claim 7, wherein The calculation formula for adjusting the initial exposure amount of the independent exposure unit in the current region according to the exposure adjustment amount to obtain the corresponding target exposure amount is expressed as: E i =ΔE i +E i0 ; Where, E i is the target exposure amount of the independent exposure unit at the i-th area; ΔE i is the corresponding exposure adjustment amount at the i-th area; E i0 is the initial exposure amount of the independent exposure unit at the i-th area.

9. The method for preparing a filtering device according to claim 1, wherein, The steps of fabricating a composite wafer include: Providing at least two wafers; wherein, the at least two wafers include a target wafer, the target wafer serves as the upper wafer substrate layer, and the bottom of the wafers other than the target wafer serves as the lower wafer support substrate layer; Bonding the at least two wafers to obtain an initial composite wafer; Thinning and chemically mechanically polishing the upper wafer substrate layer of the initial composite wafer to obtain the final composite wafer.

10. A filtering device, characterized in that, The filtering device is fabricated by the filtering device fabrication method according to any one of claims 1-9.

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