Method for frequency correction of a surface acoustic wave device

Abstract

The application provides a surface acoustic wave device frequency correction method, which comprises the following steps: providing a plurality of dummy pieces and a first surface acoustic wave device sample; uniformly etching a first dummy piece for a preset time and obtaining the etching rate of each position of the first dummy piece; setting a first preset etching thickness for a second dummy piece and etching the second dummy piece, measuring and obtaining the actual etching thickness, and obtaining a proportionality coefficient; determining whether the proportionality coefficient is within a preset proportionality coefficient deviation range; if yes, correcting the frequency of the first surface acoustic wave device sample and measuring and obtaining a frequency variation; establishing a first variation relationship between the frequency variation and the actual etching thickness; and correcting the frequency of the same batch of surface acoustic wave devices according to the first variation relationship. The frequency correction method can improve the frequency correction accuracy and the production pass rate of the surface acoustic wave device.

Description

Technical Field

[0001] This invention relates to the field of surface acoustic wave (SAW) device technology, and in particular to a frequency correction method for a SAW device. Background Technology

[0002] While surface acoustic wave (SAW) devices are widely used in the RF front-end field, they suffer from high R&D costs and low profits. Besides reducing R&D and production costs, improving the yield rate of SAW devices is also a pressing issue. Inconsistencies in processes such as on-chip warpage, photolithography precision, and coating can lead to frequency differences in different regions within the chip, resulting in severe frequency failures and significantly reducing the production yield of SAW devices.

[0003] To avoid frequency differences in different regions within the wafer and improve the production yield of surface acoustic wave (SAW) devices, existing technologies employ frequency correction techniques based on the relationship between frequency and film thickness. These techniques convert frequency variations into film thickness etching amounts, thereby ensuring that the frequencies in different regions within the wafer can be corrected to the target frequency value.

[0004] Although frequency correction based on the relationship between frequency and film thickness can ensure that the frequency of each region within the surface acoustic wave device can be corrected to the target frequency value, for some surface acoustic wave devices, the frequency difference between the edge region and the center region is large. This frequency difference and the amount of film thickness correction will gradually deviate from the relationship between frequency and film thickness. This will lead to inaccurate frequency correction in the edge region of the surface acoustic wave device, and ultimately reduce the production qualification rate of the surface acoustic wave device. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention proposes a novel frequency correction method for surface acoustic wave (SAW) devices, thereby solving the problem that frequency correction of SAW devices in the existing technologies leads to a decrease in their production qualification rate.

[0006] To solve the above-mentioned technical problems, the present invention provides a frequency correction method for a surface acoustic wave device, which includes the following steps:

[0007] Multiple dummy wafers and a first surface acoustic wave (SAW) device sample having a temperature compensation layer and a frequency correction layer deposited sequentially thereon are provided; wherein, the dummy wafer includes a substrate and a temperature compensation layer and a frequency correction layer deposited sequentially on the substrate, the thickness and process of the temperature compensation layer of the dummy wafer are the same as the thickness and process of the temperature compensation layer of the first SAW device sample, and the thickness and process of the frequency correction layer of the dummy wafer are the same as the thickness and process of the frequency correction layer of the first SAW device sample.

[0008] The first dummy wafer is etched at a uniform speed for a preset time. Based on the thickness of each position of the first dummy wafer before etching and the thickness of each position of the first dummy wafer before etching, the etching rate of each position of the first dummy wafer is obtained.

[0009] A first preset etching thickness is set for at least one target location of the second dummy wafer, and the second dummy wafer is etched to the first preset etching thickness according to the etching rate at the same location of the first dummy wafer corresponding to the target location of the second dummy wafer. The actual etching thickness of the second dummy wafer after etching is measured and obtained. Then, the corresponding ratio relationship between the first preset etching thickness and the actual etching thickness is fitted to obtain the ratio coefficient.

[0010] Determine whether the proportional coefficient is within the preset proportional coefficient deviation range:

[0011] If so, the first surface acoustic wave device sample is frequency corrected according to the etching rate, the preset etching thickness and the proportional coefficient, and the frequency change of the first surface acoustic wave device sample after frequency correction is measured.

[0012] Establish a first relationship between the frequency change and the actual etching thickness;

[0013] Based on the first change relationship, the surface acoustic wave devices that are from the same batch as the first surface acoustic wave device sample are subjected to the first frequency correction.

[0014] Preferably, the step of determining whether the proportionality coefficient is within the preset proportionality coefficient deviation range further includes:

[0015] If not, a new scaling factor is obtained until the new scaling factor is within the preset scaling factor deviation range.

[0016] Preferably, obtaining a new scaling factor specifically includes: taking a new second dummy wafer, setting a second preset etching thickness at at least one new target position on the new second dummy wafer, etching the new second dummy wafer to the second preset etching thickness according to the etching rate at the same position on the first dummy wafer corresponding to the new target position on the new second dummy wafer, measuring and obtaining the actual etching thickness of the new second dummy wafer after etching, and then fitting the corresponding proportional relationship between the second preset etching thickness and the new actual etching thickness until a new scaling factor within the preset scaling factor deviation range is obtained, and then proceeding to the next step.

[0017] Preferably, the step of uniformly etching the first dummy wafer for a preset time, and obtaining the etching rate of each location on the first dummy wafer based on the thickness of each location before etching and the thickness of the corresponding location before etching after etching, includes the following sub-steps:

[0018] Obtain the thickness of each location on the first fake piece before etching;

[0019] The frequency correction layer of the first dummy chip is etched at a constant speed for a preset time;

[0020] Obtain the thickness of each location on the first dummy piece after etching, corresponding to the thickness before etching;

[0021] The etching rate at each location of the first dummy is obtained based on the thickness of each location before etching, the thickness of each location after etching corresponding to the thickness before etching, and the preset time.

[0022] Preferably, the deviation range of the preset proportional coefficient is 1 ± 0.5%.

[0023] Preferably, the frequency correction method for the surface acoustic wave device further includes the following steps:

[0024] Take any one of the first surface acoustic wave device samples after the first frequency correction as the second surface acoustic wave device sample, and obtain the position where the variance of the frequency offset of the edge region of the second surface acoustic wave device sample is greater than 0.02, which is defined as the edge frequency correction position.

[0025] Increase the scaling factor, and perform frequency correction on the edge region of the second surface acoustic wave device sample according to the etching rate at the same position of the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor, and measure the frequency change of the edge region of the second surface acoustic wave device sample.

[0026] The dummy wafer is etched according to the etching rate at the same position on the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor. The thickness change of the edge region of the dummy wafer after etching is measured. The dummy wafer includes a substrate and a temperature compensation layer and a correction layer sequentially deposited on the substrate. The thickness and process of the temperature compensation layer of the dummy wafer are the same as those of the temperature compensation layer of the second surface acoustic wave device sample. The thickness and process of the correction layer of the dummy wafer are the same as those of the correction layer of the second surface acoustic wave device sample.

[0027] Establish a second relationship between the frequency change in the edge region and the film thickness change in the edge region;

[0028] The surface acoustic wave device after the first frequency correction is subjected to edge correction according to the second change relationship.

[0029] Preferably, the step of frequency correction of the edge region of the second surface acoustic wave device sample based on the etching rate at the same position corresponding to the first dummy wafer, the edge correction position, and the increased scaling factor, and measuring the frequency change of the edge region of the second surface acoustic wave device sample, includes the following sub-steps:

[0030] The edge region of the second surface acoustic wave device sample is frequency corrected according to the etching rate at the same position of the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor. The frequency change of the edge region of the second surface acoustic wave device sample after frequency correction is measured and the variance of the edge region frequency and the preset target frequency is calculated.

[0031] Determine whether the variance between the edge region frequency and the preset target frequency is less than or equal to 0.01:

[0032] If so, the frequency change of the edge region of the second surface acoustic wave device sample is obtained.

[0033] Preferably, the step of determining whether the variance between the edge region frequency and the preset target frequency is less than or equal to 0.01 further includes:

[0034] If not, then a new edge region frequency is acquired again until the variance between the new edge region frequency and the preset target frequency is less than or equal to 0.01.

[0035] Preferably, obtaining the new edge region frequency specifically includes: performing frequency correction on the edge region of the new second surface acoustic wave device sample based on the etching rate at the same position corresponding to the first dummy wafer, the edge correction position, and the readjusted scaling factor; measuring and obtaining the edge region frequency and the edge region frequency change of the new second surface acoustic wave device sample until the variance between the obtained new edge region frequency and the preset target frequency is less than or equal to 0.01, and then proceeding to the next step.

[0036] Compared with the prior art, the frequency correction method of the surface acoustic wave (SAW) device of the present invention firstly etches a first dummy wafer at a uniform speed for a preset time. Based on the thickness of each position of the first dummy wafer before etching and the thickness of the corresponding position before etching after etching, the etching rate of each position of the first dummy wafer is obtained. This allows the creation of an etching rate distribution map, thus taking into account the differences in etching rate caused by the thickness of the medium and the uniformity of internal stress. Then, by using the proportional relationship between the first preset etching thickness and the actual etching thickness, a proportionality coefficient is obtained, thus taking into account the deviation between the actual frequency correction amount and the theoretical frequency correction amount. Combining these two corrections can improve the frequency correction accuracy of the SAW device, thereby increasing the production qualification rate of the SAW device. Attached Figure Description

[0037] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and more readily understood through the detailed description following the accompanying drawings. In the drawings:

[0038] Figure 1 A flowchart of steps S11-S17 of the frequency correction method for a surface acoustic wave device provided in an embodiment of the present invention;

[0039] Figure 2 A schematic cross-sectional view of the dummy piece provided in an embodiment of the present invention;

[0040] Figure 3 A schematic cross-sectional view of a first surface acoustic wave device sample provided in an embodiment of the present invention;

[0041] Figure 4 A flowchart of steps S18-S22 of the surface acoustic wave device frequency correction method provided in the embodiments of the present invention;

[0042] Figure 5 The diagram shows the proportional coefficient relationship of the second fake film provided in the embodiment of the present invention. Detailed Implementation

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] This invention provides a frequency correction method for a surface acoustic wave (SAW) device, combined with... Figure 1 As shown, it includes the following steps:

[0048] S11. Provide multiple dummy wafers and a first surface acoustic wave device sample with a temperature compensation layer and a frequency correction layer deposited sequentially.

[0049] Among them, such as Figure 2 As shown, each dummy wafer 1 includes a substrate 101 and a first temperature compensation layer 102 and a first frequency correction layer 103 sequentially deposited on the substrate 101; the substrate 101 is a piezoelectric substrate, and its material and thickness are the same as those of the piezoelectric substrate of the first surface acoustic wave device sample. The function of the dummy wafer 1 is to simulate the frequency correction environment of the first surface acoustic wave device sample.

[0050] The thickness and process of the temperature compensation layer of each dummy wafer are the same as those of the temperature compensation layer of the first surface acoustic wave device sample, and the thickness and process of the frequency correction layer of each dummy wafer are the same as those of the frequency correction layer of the surface acoustic wave device sample; the process includes material selection, deposition method, deposition location, etc.

[0051] The multiple fake videos are listed as the first fake video, the second fake video, the third fake video, and so on.

[0052] like Figure 3As shown, the first surface acoustic wave device sample 200 in this embodiment includes a piezoelectric substrate 201, interdigitated electrodes 202 prepared on the piezoelectric substrate 201, a second temperature compensation layer 203 deposited on the side of the piezoelectric substrate 201 on which the interdigitated electrodes 202 are prepared, and a second frequency correction layer 204 deposited on the second temperature compensation layer 203; the material of the second temperature compensation layer 203 is silicon dioxide (SiO2), and the material of the second frequency correction layer 204 is silicon nitride (SiN).

[0053] S12. The first dummy wafer is etched at a uniform speed for a preset time. Based on the thickness of each position of the first dummy wafer before etching and the thickness of each position of the first dummy wafer before etching, the etching rate of each position of the first dummy wafer is obtained.

[0054] The preset time is set according to actual needs, and this embodiment does not impose specific limitations.

[0055] Step S12 includes the following sub-steps:

[0056] S121. Obtain the thickness of each location before etching the first dummy piece.

[0057] S122. Perform uniform etching on the frequency correction layer of the first dummy chip for a preset time.

[0058] S123. Obtain the thickness of each position corresponding to the position before etching after etching the first dummy piece.

[0059] S124. Based on the thickness of each position of the first dummy before etching, the thickness of each position of the first dummy after etching corresponding to the thickness before etching, and the preset time, obtain the etching rate of each position of the first dummy.

[0060] The etching rate can be obtained by subtracting the thickness of the first dummy at each location before etching from the thickness of the first dummy at each location after etching, and then dividing by a preset time. At the same time, the change in thickness of the first dummy can also be obtained.

[0061] Step S12 takes into account the differences in etching rate caused by the thickness of the medium and the uniformity of internal stress, and therefore can improve the frequency correction accuracy of the surface acoustic wave device by correction.

[0062] S13. Set a first preset etching thickness to be etched at at least one target position of the second dummy wafer, and etch the second dummy wafer to the first preset etching thickness according to the etching rate at the same position of the first dummy wafer corresponding to the target position of the second dummy wafer, measure and obtain the actual etching thickness of the second dummy wafer after etching, and then fit the corresponding proportional relationship between the first preset etching thickness and the actual etching thickness to obtain the proportional coefficient.

[0063] When etching the second dummy wafer, the etching is performed at the target position of the first preset etching thickness. The first preset etching thickness can be set to one value, which can also be used to obtain the actual etching thickness. Of course, in order to improve accuracy, multiple first preset etching thicknesses can also be set, so that the average value can be taken as the actual etching thickness.

[0064] The first preset etching thickness can be set to multiple locations; when etching the second dummy wafer, etching is performed sequentially according to multiple first preset etching thicknesses at different locations; during fitting, the correspondence between each first preset etching thickness and the corresponding actual etching thickness is fitted to obtain multiple initial scaling factors; the final scaling factor is the average of the multiple initial scaling factors or as shown in the figure. Figure 5 The curve in the middle.

[0065] The surface acoustic wave device frequency correction method in this embodiment is based on the frequency correction device; after obtaining the etching rate in step S12, it can be made into an etching rate distribution map and then input into the system of the frequency correction device; the first preset etching thickness of the second dummy is set according to the specific coordinates of the etching rate distribution map, and when etching the second dummy, etching is also performed based on the specific coordinates, that is, etching is performed based on the position and etching rate corresponding to the specific coordinate position.

[0066] S14. Determine whether the proportional coefficient is within the preset proportional coefficient deviation range.

[0067] The preset proportional coefficient deviation range is 1 ± 0.5%, that is, the preset proportional coefficient K deviates from 1 by ± 0.5%.

[0068] If so, proceed to the next step, S15.

[0069] If not, obtain a new scaling factor until the new scaling factor is within the preset scaling factor deviation range, then proceed to the next step S15. Figure 5 As shown, the first preset etching thickness is set to 5, such as... Figure 5 The five punctuation marks in the text have a scale factor k of 0.9606, as shown in the example. Figure 5 The lines in the diagram are not within the range of 1±0.5%, so a new scaling factor needs to be obtained.

[0070] Obtaining a new scaling factor specifically includes: taking a new second dummy wafer, equivalent to a third dummy wafer; setting a second preset etching thickness at at least one new target position of the third dummy wafer according to the etching rate distribution map; etching the third dummy wafer to the second preset etching thickness according to the etching rate at the same position of the first dummy wafer corresponding to the new target position of the third dummy wafer; measuring and obtaining the actual etching thickness of the third dummy wafer after etching; fitting the corresponding ratio between the preset etching thickness of the third dummy wafer and the actual etching thickness of the third dummy wafer until a new scaling factor within the preset scaling factor deviation range is obtained; then proceeding to the next step S15, where the scaling factor used in step S15 is the new scaling factor within the preset scaling factor deviation range. If a new scaling factor within the preset scaling factor deviation range is still not obtained, the fourth dummy wafer, fifth dummy wafer, etc., are etched in the same way until a new scaling factor within the preset scaling factor deviation range is obtained; the actual etching thickness in the next step S16 is the actual etching thickness when the new scaling factor within the preset scaling factor deviation range is obtained. The etching method for the third dummy wafer is the same as or similar to that for the second dummy wafer, and will not be elaborated here. The range or value of the second preset etching thickness can be the same as or different from the range or value of the first preset etching thickness.

[0071] Step S14 takes into account the discrepancy between the actual frequency correction amount and the theoretical frequency correction amount, and therefore can improve the frequency correction accuracy of the surface acoustic wave device through correction.

[0072] S15. Then, the first surface acoustic wave device sample is frequency corrected according to the etching rate and the proportional coefficient, and the frequency change of the first surface acoustic wave device sample after frequency correction is measured.

[0073] S16. Establish a first relationship between the frequency change and the actual etching thickness.

[0074] The first change relationship can be a polynomial relationship or a corresponding function, etc.

[0075] S17. Based on the first change relationship, perform the first frequency correction on the surface acoustic wave devices that are from the same batch as the first surface acoustic wave device sample.

[0076] The etching and frequency correction mentioned above are the same concept, that is, the purpose of etching is to correct the frequency, and both are performed on the frequency correction area. In this field, frequency correction is to change the thickness of the frequency correction layer by etching so that the frequency correction layer reaches the required thickness, thereby achieving the purpose of frequency correction.

[0077] By first determining the correct relationship between the frequency variation of the surface acoustic wave (SAW) device and the actual etching thickness, and then performing the first frequency correction on the same batch of SAW devices, the production qualification rate of that batch of SAW devices can be improved.

[0078] Steps S12 to S17 in the frequency correction method of the surface acoustic wave device in this embodiment are performed based on the frequency correction device, as detailed below:

[0079] 12. Calibrate the coordinate system of the film thickness gauge to make it correspond one-to-one with the coordinate system of the probe station; send the first dummy wafer into the frequency correction machine, etch the whole wafer at a uniform speed for a certain period of time, and use the film thickness gauge to measure the thickness or film thickness of the first dummy wafer before and after frequency correction to obtain the film thickness change of the first dummy wafer. Combined with the etching time, the etching rate distribution map of the first dummy wafer can be obtained. Then, the etching rate distribution map is input into the frequency correction system of the frequency correction device.

[0080] 13. Send the second dummy wafer into the frequency correction machine and etch different preset thicknesses (20nm: 10nm: 60nm) of the second dummy wafer according to a specific rate distribution map coordinate system. Measure the thickness of the second dummy wafer before and after etching to obtain the actual film thickness change of the second dummy wafer. At the same time, obtain the correspondence between the theoretical etching thickness and the actual etching thickness. Fit the relationship between the two to obtain the proportionality coefficient, which is close to 1. Here, the theoretical etching amount is the preset thickness or the preset etching thickness, and the actual etching amount is obtained by measurement after etching is completed.

[0081] 14. If the scaling factor deviates from 1 by ±0.5%, the scaling factor needs to be corrected. That is, the current scaling factor is input into the above frequency correction system, the new second dummy is etched repeatedly, and a new scaling factor is obtained by fitting until the final new scaling factor is within ±0.5% of the deviation from 1. The actual film thickness change at this time is recorded, that is, the actual etching amount or the actual etching thickness.

[0082] 15. Correct the frequency of the first surface acoustic wave device sample according to the specific rate distribution map coordinates mentioned above, and measure the corresponding frequency change.

[0083] 16. Establish the correspondence between the frequency change and the actual film thickness change, and fit it into a polynomial relationship.

[0084] 17. Based on the above polynomial relationship, perform the first frequency correction on the surface acoustic wave device that is from the same batch as the first surface acoustic wave device sample.

[0085] Compared with the prior art, the frequency correction method of the surface acoustic wave (SAW) device in this embodiment firstly etches a first dummy wafer at a uniform speed for a preset time. Based on the thickness of each position of the first dummy wafer before etching and the thickness of the corresponding position before etching after etching, the etching rate of each position of the first dummy wafer is obtained. This allows the creation of an etching rate distribution map, thus taking into account the differences in etching rate caused by the thickness of the medium and the uniformity of internal stress. Then, by using the proportional relationship between the first preset etching thickness and the actual etching thickness, a proportionality coefficient is obtained, thus taking into account the deviation between the actual frequency correction amount and the theoretical frequency correction amount. Combining these two corrections can improve the frequency correction accuracy of the SAW device, thereby increasing the production qualification rate of the SAW device.

[0086] Existing surface acoustic wave (SAW) device frequency correction techniques suffer from limitations due to manufacturing deviations in some products. These deviations result in significant frequency differences between the edge and center regions, limited film thickness variations, and a map coordinate system radius smaller than or equal to the wafer radius. These factors prevent the correction amount in the edge regions of the SAW device from meeting the fitted polynomial curve, further reducing the yield rate of SAW devices during production. Therefore, the SAW device frequency correction method of this invention aims to further improve its correction accuracy and thus increase the production yield rate of SAW devices. Figure 4 As shown, the following steps are included after step 17.

[0087] S18. Take any one of the first surface acoustic wave device samples after the first frequency correction as the second surface acoustic wave device sample, and obtain the position where the variance of the frequency offset of the edge region of the second surface acoustic wave device sample is greater than 0.02, and define it as the edge frequency correction position.

[0088] The edge correction position can also be regarded as the coordinate position of the edge.

[0089] S19. Increase the scaling factor, and use the etching rate at the same position of the edge correction position corresponding to the first dummy, the edge correction position, and the increased scaling factor to correct the frequency of the edge region of the second surface acoustic wave device sample, and measure the frequency change of the edge region of the second surface acoustic wave device sample.

[0090] The increased proportionality coefficient is 1 + 0.05%, meaning the increased proportionality coefficient deviates from 1 by 0.05%.

[0091] Step 19 includes the following sub-steps:

[0092] The edge region of the second surface acoustic wave device sample is frequency corrected based on the etching rate at the same position on the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor. The edge region frequency and the change in edge region frequency of the second surface acoustic wave device sample after frequency correction are measured and obtained, and the variance between the edge region frequency and the preset target frequency is calculated.

[0093] Determine whether the variance between the edge region frequency and the preset target frequency is less than or equal to 0.01:

[0094] If so, the frequency change of the edge region of the second surface acoustic wave device sample is obtained, that is, the frequency change of the edge region of the second surface acoustic wave device sample after frequency correction.

[0095] If not, then a new edge region frequency is acquired again until the variance between the new edge region frequency and the preset target frequency is less than 0.01.

[0096] The process of re-acquiring the new edge region frequency specifically includes: performing frequency correction on the edge region of the new second surface acoustic wave device sample based on the etching rate at the same position corresponding to the first dummy wafer, the edge correction position, and the readjusted scaling factor; measuring and acquiring the edge region frequency and edge region frequency change of the new second surface acoustic wave device sample until the variance between the obtained edge region frequency and the preset target frequency is less than 0.01; and then proceeding to the next step S20. The edge region frequency change used in the next step S21 is the edge region frequency change of the new second surface acoustic wave device sample.

[0097] The readjusted scaling factor is the increased scaling factor, which is different from the first increased scaling factor. It is mainly used to ensure that the variance between the obtained edge region frequency and the preset target frequency is less than 0.01.

[0098] S20. The co-electrode is etched according to the etching rate corresponding to the edge correction position, the edge correction position, and the increased scaling factor, and the change in film thickness in the edge region of the co-electrode after etching is measured.

[0099] The accompanying wafer includes a substrate and a temperature compensation layer and a frequency correction layer sequentially deposited on the substrate. The thickness and manufacturing process of the temperature compensation layer of the accompanying wafer are the same as those of the temperature compensation layer of the second surface acoustic wave device sample. Similarly, the thickness and manufacturing process of the frequency correction layer of the accompanying wafer are the same as those of the frequency correction layer of the second surface acoustic wave device sample. The accompanying wafer is essentially the same as or similar to the aforementioned dummy wafer; however, this step is referred to as the accompanying wafer for ease of distinction.

[0100] The change in film thickness in the edge region mentioned in this step is the actual etching thickness of the edge region of the substrate, which is to reflect the actual thickness change of the edge region of the substrate after etching.

[0101] S21. Establish a second relationship between the frequency change of the edge region and the film thickness change of the edge region.

[0102] The second change relationship can be a polynomial relationship, a corresponding function, or a polynomial curve, etc.

[0103] S22. Perform edge frequency correction on the surface acoustic wave device after the first frequency correction according to the second change relationship.

[0104] The frequency correction method for the surface acoustic wave device in this embodiment first performs frequency correction on the entire surface acoustic wave device, and then performs edge frequency correction on the surface acoustic wave device after the first frequency correction. The data in the edge region is richer, which can greatly improve the frequency correction accuracy of the edge region of the surface acoustic wave device, thereby further improving the production qualification rate of the surface acoustic wave device.

[0105] Example 2

[0106] This invention provides a surface acoustic wave device, which is obtained by frequency correction using the surface acoustic wave device frequency correction method in Embodiment 1.

[0107] Since the surface acoustic wave device in this embodiment is obtained by frequency correction using the surface acoustic wave device frequency correction method in embodiment one, it can also achieve the technical effect achieved by the surface acoustic wave device frequency correction method in embodiment one, and will not be elaborated here.

[0108] It should be noted that the various embodiments described above with reference to the accompanying drawings are merely illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be included within the scope of the present invention. Furthermore, unless the context otherwise requires, words appearing in the singular include those in the plural, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.

Claims

1. A frequency correction method for a surface acoustic wave device, characterized in that, The frequency correction method for the surface acoustic wave device includes the following steps: Multiple dummy wafers and a first surface acoustic wave (SAW) device sample having a temperature compensation layer and a frequency correction layer deposited sequentially thereon are provided; wherein, the dummy wafer includes a substrate and a temperature compensation layer and a frequency correction layer deposited sequentially on the substrate, the thickness and process of the temperature compensation layer of the dummy wafer are the same as the thickness and process of the temperature compensation layer of the first SAW device sample, and the thickness and process of the frequency correction layer of the dummy wafer are the same as the thickness and process of the frequency correction layer of the first SAW device sample. The first dummy wafer is etched at a uniform speed for a preset time. Based on the thickness of each position of the first dummy wafer before etching and the thickness of each position of the first dummy wafer before etching, the etching rate of each position of the first dummy wafer is obtained. A first preset etching thickness is set for at least one target location of the second dummy wafer, and the second dummy wafer is etched to the first preset etching thickness according to the etching rate at the same location of the first dummy wafer corresponding to the target location of the second dummy wafer. The actual etching thickness of the second dummy wafer after etching is measured and obtained. Then, the corresponding ratio relationship between the first preset etching thickness and the actual etching thickness is fitted to obtain the ratio coefficient. Determine whether the proportional coefficient is within the preset proportional coefficient deviation range: If so, the first surface acoustic wave device sample is frequency corrected according to the etching rate and the proportional coefficient, and the frequency change of the first surface acoustic wave device sample after frequency correction is measured. Establish a first relationship between the frequency change and the actual etching thickness; Based on the first change relationship, the surface acoustic wave devices that are from the same batch as the first surface acoustic wave device sample are subjected to the first frequency correction.

2. The frequency correction method for a surface acoustic wave device as described in claim 1, characterized in that, The step of determining whether the scaling factor is within the preset scaling factor deviation range further includes: If not, a new scaling factor is obtained until the new scaling factor is within the preset scaling factor deviation range.

3. The frequency correction method for a surface acoustic wave device as described in claim 2, characterized in that, Obtaining a new scaling factor specifically includes: taking a new second dummy wafer, setting a second preset etching thickness at at least one new target position on the new second dummy wafer, etching the new second dummy wafer to the second preset etching thickness according to the etching rate at the same position on the first dummy wafer corresponding to the new target position on the new second dummy wafer, measuring and obtaining the actual etching thickness of the new second dummy wafer after etching, and then fitting the corresponding proportional relationship between the second preset etching thickness and the new actual etching thickness until a new scaling factor within the preset scaling factor deviation range is obtained, and then proceeding to the next step.

4. The frequency correction method for a surface acoustic wave device as described in claim 1, characterized in that, The step of uniformly etching the first dummy wafer for a preset time, and obtaining the etching rate at various locations on the first dummy wafer based on the thickness of each location before etching and the thickness of the corresponding locations before etching after etching, includes the following sub-steps: Obtain the thickness of each location on the first fake piece before etching; The frequency correction layer of the first dummy chip is etched at a constant speed for a preset time; Obtain the thickness of each location on the first dummy piece after etching, corresponding to the thickness before etching; The etching rate at each location of the first dummy is obtained based on the thickness of each location before etching, the thickness of each location after etching corresponding to the thickness before etching, and the preset time.

5. The frequency correction method for a surface acoustic wave device as described in claim 1, characterized in that, The preset proportional coefficient deviation range is 1 ± 0.5%.

6. The frequency correction method for a surface acoustic wave device as described in claim 1, characterized in that, The frequency correction method for the surface acoustic wave device further includes the following steps: Take any one of the first surface acoustic wave device samples after the first frequency correction as the second surface acoustic wave device sample, and obtain the position where the variance of the frequency offset of the edge region of the second surface acoustic wave device sample is greater than 0.02, which is defined as the edge frequency correction position. Increase the scaling factor, and perform frequency correction on the edge region of the second surface acoustic wave device sample according to the etching rate at the same position of the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor, and measure the frequency change of the edge region of the second surface acoustic wave device sample. The dummy wafer is etched according to the etching rate at the same position on the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor. The thickness change of the edge region of the dummy wafer after etching is measured. The dummy wafer includes a substrate and a temperature compensation layer and a correction layer sequentially deposited on the substrate. The thickness and process of the temperature compensation layer of the dummy wafer are the same as those of the temperature compensation layer of the second surface acoustic wave device sample. The thickness and process of the correction layer of the dummy wafer are the same as those of the correction layer of the second surface acoustic wave device sample. Establish a second relationship between the frequency change in the edge region and the film thickness change in the edge region; The surface acoustic wave device after the first frequency correction is subjected to edge correction according to the second change relationship.

7. The frequency correction method for a surface acoustic wave device as described in claim 6, characterized in that, The step of frequency correction of the edge region of the second surface acoustic wave device sample based on the etching rate at the same position corresponding to the first dummy wafer, the edge correction position, and the increased scaling factor, and measuring the frequency change of the edge region of the second surface acoustic wave device sample, includes the following sub-steps: The edge region of the second surface acoustic wave device sample is frequency corrected according to the etching rate at the same position of the first dummy wafer corresponding to the edge correction position, the edge correction position, and the increased scaling factor. The edge region frequency and the edge region frequency change of the second surface acoustic wave device sample after frequency correction are measured and obtained, and the variance of the edge region frequency and the preset target frequency are calculated. Determine whether the variance between the edge region frequency and the preset target frequency is less than or equal to 0.01: If so, the frequency change of the edge region of the second surface acoustic wave device sample is obtained.

8. The frequency correction method for a surface acoustic wave device as described in claim 7, characterized in that, The step of determining whether the variance between the edge region frequency and the preset target frequency is less than or equal to 0.01 further includes: If not, then a new edge region frequency is acquired again until the variance between the new edge region frequency and the preset target frequency is less than or equal to 0.

01.

9. The frequency correction method for a surface acoustic wave device as described in claim 8, characterized in that, The process of re-acquiring the new edge region frequency specifically includes: performing frequency correction on the edge region of the new second surface acoustic wave device sample based on the etching rate at the same position corresponding to the first dummy wafer, the edge correction position, and the readjusted scaling factor; measuring and acquiring the edge region frequency and the edge region frequency change of the new second surface acoustic wave device sample until the variance between the obtained new edge region frequency and the preset target frequency is less than or equal to 0.01, and then proceeding to the next step.

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