Semiconductor structure and forming method therefor

Abstract

Provided in the present invention are a semiconductor structure and a forming method therefor. The semiconductor structure comprises: a piezoelectric layer; two interdigital transducers located on the piezoelectric layer; and a plurality of reflection structures located between the two interdigital transducers, wherein at least two of the following three aspects are irregular: the shape of the reflection structures, the size of the reflection structures and the arrangement of the plurality of reflection structures, such that the degree of scattering of the reflection structures is increased, causing surface acoustic waves to undergo a plurality of different reflection angles during the reflection process to achieve reverse phase elimination, thereby achieving the effect of further reducing interference, and improving the performance of the ultimately formed semiconductor structure.

Description

Semiconductor structure and method for forming the same

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 4, 2024, with application number 202410010633.4 and invention name “Semiconductor structure and method for forming the same”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor structure and a method for forming the same. Background Art

[0003] Piezoelectric surface acoustic wave (SAW) filters are widely used in radio frequency (RF) front-end chips for wireless communication devices such as mobile phones and base stations. They utilize a metal electrode layer on the surface of a piezoelectric layer to excite surface acoustic waves, achieving acoustic-to-electrical conversion and filtering the signal. SAW resonators are the basic building blocks of SAW filters. Connecting different SAW resonators on the same piezoelectric layer through metal traces forms the core of a SAW filter.

[0004] The increase in communication frequency bands and the miniaturization of communication equipment require SAW filters to be smaller, resulting in congested resonators in limited space. Surface acoustic waves (SAWs) are elastic waves that propagate on solid surfaces. When two SAW resonators are closely spaced (d ≤ 30 μm, where d is the spacing) and have similar wavelengths (|λ1-λ2| ≤ 0.05 μm, where λ is the wavelength), the surface acoustic waves they excite on the substrate surface interfere with each other, degrading the filter's overall performance.

[0005] Therefore, when the distance between two adjacent SAW resonators is close, how to reduce or even eliminate the mutual interference of the surface acoustic waves excited by them on the substrate surface to ensure the overall performance of the filter is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide a semiconductor structure and a formation method to avoid the mutual interference of surface acoustic waves excited on the surfaces of two adjacent resonators, thereby improving the overall performance of the filter.

[0007] To solve the above problems, the present invention provides a semiconductor structure, comprising: a piezoelectric layer; two interdigital transducers located on the piezoelectric layer; and a plurality of reflective structures located between the two interdigital transducers, wherein at least two of the shape of the reflective structure, the size of the reflective structure, and the arrangement of the plurality of reflective structures are irregular.

[0008] Optionally, the shape of the reflection structure projected on the surface of the piezoelectric layer is irregular.

[0009] Optionally, the reflective structure includes a plurality of first reflective portions arranged along a first direction, and the shapes of the projections of the first reflective portions on the surface of the piezoelectric layer include one or more combinations of a trapezoid, a triangle and an arc, and the first direction is parallel to the surface of the piezoelectric layer.

[0010] Optionally, the first reflective portion protrudes from a side surface of the reflective structure.

[0011] Optionally, the first reflective portion is recessed in a side surface of the reflective structure.

[0012] Optionally, the plurality of first reflective portions are symmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0013] Optionally, the plurality of first reflective portions are asymmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0014] Optionally, the spacing between the plurality of first reflective portions in the first direction is the same.

[0015] Optionally, the spacings between the plurality of first reflective portions in the first direction are different.

[0016] Optionally, the sizes of the plurality of first reflecting parts are the same.

[0017] Optionally, the sizes of the plurality of first reflecting parts are different and irregular.

[0018] Optionally, the sizes of the multiple reflective structures are the same.

[0019] Optionally, the sizes of the multiple reflective structures are different and irregular.

[0020] Optionally, the plurality of reflective structures are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0021] Optionally, the spacing between the multiple reflective structures along the first direction is the same.

[0022] Optionally, the spacing between the multiple reflective structures along the first direction is different.

[0023] Optionally, the spacing between the multiple reflective structures along the second direction is the same.

[0024] Optionally, the spacing between the multiple reflective structures along the second direction is different.

[0025] Optionally, when the shape of the reflection structure projected on the surface of the piezoelectric layer is a regular shape, the shape of the reflection structure includes one or a combination of a circle and a polygon.

[0026] Optionally, the sizes of the multiple reflective structures are different and irregular.

[0027] Optionally, the plurality of reflective structures have different spacings along a third direction, and the third direction is parallel to the surface of the piezoelectric layer.

[0028] Optionally, the spacings between the multiple reflective structures along a fourth direction are different, the fourth direction is parallel to the surface of the piezoelectric layer, and the fourth direction is perpendicular to the third direction.

[0029] In response to the above-mentioned semiconductor structure, the present invention also provides a method for forming a semiconductor structure, including: providing a piezoelectric layer; forming two interdigital transducers on the surface of the piezoelectric layer; forming multiple reflective structures on the surface of the piezoelectric layer between the two interdigital transducers, wherein at least two of the three items of the shape of the reflective structure, the size of the reflective structure and the arrangement of the multiple reflective structures are irregular.

[0030] Optionally, the shape of the reflection structure projected on the surface of the piezoelectric layer is irregular.

[0031] Optionally, the reflective structure includes a plurality of first reflective portions arranged along a first direction, and the shapes of the projections of the first reflective portions on the surface of the piezoelectric layer include one or more combinations of a trapezoid, a triangle and an arc, and the first direction is parallel to the surface of the piezoelectric layer.

[0032] Optionally, the sizes of the multiple reflective structures are the same.

[0033] Optionally, the sizes of the multiple reflective structures are different and irregular.

[0034] Optionally, the plurality of reflective structures are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0035] Optionally, when the shape of the reflection structure projected on the surface of the piezoelectric layer is a regular shape, the shape of the reflection structure includes one or a combination of a circle and a polygon.

[0036] Optionally, the sizes of the multiple reflective structures are different and irregular.

[0037] Optionally, the plurality of reflective structures have different spacings along a third direction, and the third direction is parallel to the surface of the piezoelectric layer.

[0038] Optionally, the spacings between the multiple reflective structures along a fourth direction are different, the fourth direction is parallel to the surface of the piezoelectric layer, and the fourth direction is perpendicular to the third direction.

[0039] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0040] In the semiconductor structure scheme of the present invention, there are multiple reflection structures between the two resonators, wherein at least two of the three items of the shape of the reflection structure, the size of the reflection structure and the arrangement of the multiple reflection structures are irregular, thereby improving the scattering degree of the surface acoustic wave at the reflection structure, so that the reflected surface acoustic wave has more different reflection angles, thereby reducing the probability of superposition of reflected surface acoustic waves and increasing the probability of mutual cancellation of reflected surface acoustic waves, so as to achieve the effect of reducing mutual interference between interdigital transducers and reducing the influence of reflected surface acoustic waves on the interdigital transducers, thereby improving the overall performance of the formed semiconductor structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG1 is a top view of a semiconductor structure;

[0042] FIG2 is an enlarged view of the dotted line portion in FIG1 ;

[0043] FIG3 is a top view of another semiconductor structure;

[0044] FIG4 is an enlarged view of the dotted line portion in FIG3 ;

[0045] 5 to 8 are schematic diagrams showing the process of forming a semiconductor structure according to a first embodiment of the present invention;

[0046] 9 to 10 are schematic diagrams showing a method for forming a semiconductor structure according to a second embodiment of the present invention;

[0047] 11 to 13 are schematic diagrams showing a method for forming a semiconductor structure according to a third embodiment of the present invention;

[0048] 14 to 16 are schematic diagrams showing the process of forming a semiconductor structure according to a fourth embodiment of the present invention;

[0049] 17 to 19 are schematic diagrams showing a method for forming a semiconductor structure according to a fifth embodiment of the present invention;

[0050] 20 to 22 are schematic diagrams showing a method for forming a semiconductor structure according to a sixth embodiment of the present invention;

[0051] 23 to 25 are schematic structural diagrams of a method for forming a semiconductor structure according to a seventh embodiment of the present invention. DETAILED DESCRIPTION

[0052] As mentioned in the background art, there are still many problems with the overall performance of the filter, which will be specifically explained with reference to FIG. 1 to FIG. 4 .

[0053] First, referring to FIG. 1 and FIG. 2 , a semiconductor structure includes a piezoelectric layer 100 , a first resonator 101 and a second resonator 102 located on the piezoelectric layer 100 , and a reflective structure 103 located between the first resonator 101 and the second resonator 102 .

[0054] 3 and 4 , a semiconductor structure includes a piezoelectric layer 200 , a first resonator 201 and a second resonator 202 located on the piezoelectric layer 200 , and a reflective structure 203 located between the first resonator 201 and the second resonator 202 .

[0055] In the above embodiment, the arrangement of the reflective structure 103 and the reflective structure 203 is generally regular, and there are many parallel reflective surfaces, which easily lead to the superposition of reflected sound waves. When this superposition reaches a certain extent, it will cause substantial interference to the filter, affecting the overall performance of the filter and being detrimental to the use of the filter.

[0056] On this basis, the present invention provides a semiconductor structure having multiple reflection structures between two resonators, wherein at least two of the three items of the shape of the reflection structure, the size of the reflection structure, and the arrangement of the multiple reflection structures are irregular, thereby improving the scattering degree of surface acoustic waves at the reflection structure, so that the reflected surface acoustic waves have more different reflection angles, thereby reducing the probability of superposition of reflected surface acoustic waves and increasing the probability of mutual cancellation of reflected surface acoustic waves, so as to achieve the effect of reducing mutual interference between interdigital transducers and reducing the impact of reflected surface acoustic waves on the interdigital transducers, thereby improving the overall performance of the formed semiconductor structure.

[0057] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0058] 5 to 8 are schematic structural diagrams of a method for forming a semiconductor structure according to a first embodiment of the present invention.

[0059] First, please refer to FIG. 5 . The present invention provides a method for forming a semiconductor structure, including: providing a piezoelectric layer 300 .

[0060] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0061] Referring to FIG. 6 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0062] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0063] In other embodiments, the material of the interdigital electrodes of the IDT may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, copper, etc.

[0064] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0065] In other embodiments, the number of IDTs may be set according to actual needs.

[0066] 7 and 8 , the forming method further includes: forming a plurality of reflective structures 302 between two IDTs 301 .

[0067] FIG8 is an enlarged view of the arrangement and distribution of some of the multiple reflective structures in FIG7 . It should be noted that the number of reflective structures in the figure is only for illustration purposes, and the specific number of reflective structures is designed according to actual needs.

[0068] In this embodiment, the material of the reflective structure 302 is the same as the material of the interdigital electrodes of the IDT 301 .

[0069] In this embodiment, the thickness of the reflective structure 302 is the same as the thickness of the interdigital electrodes of the IDT 301 .

[0070] In this embodiment, the shape of the reflection structure 302 projected on the surface of the piezoelectric layer 300 is a regular shape. Specifically, the shape of the reflection structure 302 projected on the surface of the piezoelectric layer 300 is a circle.

[0071] In other embodiments, the shape of the reflection structure projected on the surface of the piezoelectric layer is an irregular shape.

[0072] In this embodiment, the step of forming the reflective structure 302 includes: forming a reflective structure layer on the surface of the piezoelectric layer 300 between the two IDTs 301 ; and patterning the reflective structure layer to form a plurality of reflective structures 302 between the two IDTs 301 .

[0073] In this embodiment, the radius sizes of adjacent reflective structures 302 are different and irregular.

[0074] In other embodiments, the radius sizes of adjacent reflective structures 302 are the same.

[0075] In this embodiment, the radius R of the reflective structure 302 ranges from 5 to 10 microns, and the wavelength of the surface acoustic waves propagating through the piezoelectric layer ranges from approximately 1 to 5 microns. If the reflective structure 302 is too small, ideal reflection will not be achieved, and diffraction may even occur, allowing the acoustic waves to propagate around obstacles. If the reflective structure 302 is too large, the degree of scattering of the surface acoustic waves at the reflective structure will be reduced.

[0076] In this embodiment, the plurality of reflective structures 302 have different intervals along a third direction, which is parallel to the surface of the piezoelectric layer 300 .

[0077] In this embodiment, the multiple reflective structures 302 have different intervals along the fourth direction. The fourth direction is parallel to the surface of the piezoelectric layer 300 and perpendicular to the third direction.

[0078] In this embodiment, the third direction is set as the X-axis direction, and the fourth direction is set as the Y-axis direction.

[0079] It should be noted that the fourth direction mentioned in the specification may not be parallel to the direction of surface acoustic wave propagation between the two IDTs 301 , and the Y-axis direction in this embodiment is only a specific embodiment.

[0080] In this embodiment, the interval a between adjacent reflective structures 302 ranges from 0 micrometers to 10 micrometers. If the interval a between adjacent reflective structures 302 is too large, an effective sound wave barrier cannot be provided.

[0081] Correspondingly, using the above-mentioned formation method, please refer to Figures 7 to 8. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and multiple reflective structures 302 located between the two interdigital transducers 301, wherein at least two of the three items of the shape of the reflective structure 302, the size of the reflective structure 302, and the arrangement of the multiple reflective structures 302 are irregular.

[0082] In this embodiment, the shape of the projection of the reflective structure 302 on the surface of the piezoelectric layer is a regular shape. Specifically, the shape of the projection of the reflective structure 302 on the surface of the piezoelectric layer 300 is a circle.

[0083] In this embodiment, the sizes of the plurality of reflective structures 302 are different and irregular. Specifically, the radius sizes of the plurality of reflective structures 302 are different and irregular. In this embodiment, the radius size of the reflective structures 302 ranges from 5 micrometers to 10 micrometers.

[0084] In other embodiments, the sizes of the multiple reflective structures 302 are the same. Specifically, the radius sizes of the multiple reflective structures 302 are the same.

[0085] In this embodiment, the spacings between the plurality of reflective structures 302 along the third direction are different, and the third direction is parallel to the surface of the piezoelectric layer 300 .

[0086] In this embodiment, the spacings between the plurality of reflective structures 302 along the fourth direction are different. The fourth direction is parallel to the surface of the piezoelectric layer and perpendicular to the third direction.

[0087] In this embodiment, the third direction is set as the X-axis direction, and the fourth direction is set as the Y-axis direction.

[0088] In this embodiment, the distance between adjacent reflective structures 302 ranges from 0 micrometers to 10 micrometers.

[0089] In this embodiment, the arrangement of the plurality of reflective structures 302 is irregular.

[0090] In this embodiment, the size of the reflection structure 302 and the arrangement of multiple reflection structures 302 are irregular, which increases the scattering degree of the surface acoustic wave at the reflection structure 302, so that the reflected surface acoustic wave has more different reflection angles, thereby reducing the probability of superposition of reflected surface acoustic waves and increasing the probability of mutual cancellation of reflected surface acoustic waves, so as to achieve the effect of reducing mutual interference between the interdigital transducers and reducing the impact of the reflected surface acoustic wave on the interdigital transducers, thereby improving the overall performance of the formed semiconductor structure.

[0091] 9 and 10 are schematic structural diagrams of a method for forming a semiconductor structure according to a second embodiment of the present invention.

[0092] The difference between this embodiment and the first embodiment is that the shape of the projection of the reflective structure on the surface of the piezoelectric layer is a polygon, specifically a rhombus in this embodiment.

[0093] The viewing direction of FIG. 9 is consistent with that of FIG. 7 . FIG. 10 is an enlarged view of a portion of the arrangement of the plurality of reflective structures 303 in FIG. 9 .

[0094] 9 and 10 , the present invention provides a method for forming a semiconductor structure, including providing a piezoelectric layer 300 .

[0095] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0096] Continuing to refer to FIG. 9 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0097] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0098] In other embodiments, the material of the interdigital electrodes of the IDT 301 may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, or copper.

[0099] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0100] In other embodiments, the number of IDTs may be set according to actual needs.

[0101] 9 and 10 , the forming method further includes: forming a plurality of reflective structures 303 between the two IDTs 301 , wherein the reflective structures 303 are projected onto the surface of the piezoelectric layer 300 in a regular rhombus shape.

[0102] In this embodiment, the material of the reflective structure 303 is the same as the material of the interdigital electrodes of the IDT.

[0103] In this embodiment, the thickness of the reflective structure 303 is the same as the thickness of the interdigital electrodes of the IDT.

[0104] In this embodiment, the side lengths a of adjacent reflective structures 303 are different and irregular. In this embodiment, the internal angles α of adjacent reflective structures 303 are the same.

[0105] In other embodiments, the side lengths a of adjacent reflective structures 303 are the same. In other embodiments, the inner angles α of adjacent reflective structures 303 may be different and irregular. In other embodiments, the side lengths a of adjacent reflective structures 303 are different and irregular.

[0106] In other embodiments, the inner angles α of adjacent reflective structures 303 may be different and irregular.

[0107] In this embodiment, the side length a of the reflective structure 303 ranges from 5 microns to 15 microns, and the wavelength of the surface acoustic wave propagated by the piezoelectric layer ranges from approximately 1 to 5 microns. If the reflective structure 303 is too small, the ideal reflection effect will not be achieved, and diffraction may even occur, allowing the sound wave to propagate around obstacles. If the reflective structure 303 is too large, the degree of scattering of the surface acoustic wave at the reflective structure will be reduced.

[0108] In this embodiment, the internal angle α of the reflective structure 303 ranges from 60° to 120°.

[0109] In this embodiment, the spacings between the plurality of reflective structures 302 along the third direction are different, and the third direction is parallel to the surface of the piezoelectric layer 300 .

[0110] In this embodiment, the spacings between the plurality of reflective structures 303 along the fourth direction are different. The fourth direction is parallel to the surface of the piezoelectric layer 300 and is perpendicular to the third direction.

[0111] In this embodiment, the third direction is set as the X-axis direction, and the fourth direction is set as the Y-axis direction.

[0112] In this embodiment, the interval b between adjacent reflective structures 303 ranges from 0 micrometers to 10 micrometers. If the interval between adjacent reflective structures 303 is too large, an effective sound wave barrier cannot be provided.

[0113] Correspondingly, using the above-mentioned formation method, please refer to Figures 9 to 10. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and multiple reflective structures 303 located between the two interdigital transducers 301, wherein at least two of the three items of the shape of the reflective structure 303, the size of the reflective structure 303, and the arrangement of the multiple reflective structures 303 are irregular.

[0114] In this embodiment, the shape of the reflection structure 303 projected on the surface of the piezoelectric layer 300 is a regular shape. Specifically, the shape of the reflection structure 303 projected on the surface of the piezoelectric layer 300 is a rhombus.

[0115] In this embodiment, the side lengths of adjacent reflective structures 303 are different and irregular, and the inner angles of adjacent reflective structures 303 are the same.

[0116] In other embodiments, the side lengths of adjacent reflective structures 303 are the same, and the inner angles of adjacent reflective structures 303 are different and irregular.

[0117] In other embodiments, the side lengths of adjacent reflective structures 303 are different and irregular, and the inner angles of adjacent reflective structures 303 are different and irregular.

[0118] In this embodiment, the side length of the reflective structure 303 ranges from 5 micrometers to 15 micrometers.

[0119] In this embodiment, the internal angle of the reflective structure 303 ranges from 60° to 120°.

[0120] In this embodiment, the arrangement of the plurality of reflective structures 303 is irregular.

[0121] In this embodiment, the spacing between the multiple reflective structures 303 along the third direction is different, the third direction is parallel to the surface of the piezoelectric layer, and the spacing between the multiple reflective structures 303 along the fourth direction is different, the fourth direction is parallel to the surface of the piezoelectric layer, and the fourth direction is perpendicular to the third direction.

[0122] In this embodiment, the third direction is set as the X-axis direction, and the fourth direction is set as the Y-axis direction.

[0123] In this embodiment, the interval b between adjacent reflective structures 303 ranges from 0 micrometers to 10 micrometers.

[0124] In this embodiment, the size of the reflection structure 303 and the arrangement of multiple reflection structures 303 are irregular, which increases the scattering degree of the surface acoustic wave at the reflection structure 303 and makes the reflected surface acoustic wave have more different reflection angles, thereby reducing the probability of superposition of reflected surface acoustic waves and increasing the probability of mutual cancellation of reflected surface acoustic waves, so as to achieve the effect of reducing mutual interference between the interdigital transducers and reducing the impact of the reflected surface acoustic wave on the interdigital transducers, thereby improving the overall performance of the formed semiconductor structure.

[0125] 11 to 13 are schematic structural diagrams of a method for forming a semiconductor structure according to a third embodiment of the present invention.

[0126] The difference between the third embodiment and the first and second embodiments is that the shape of the reflection structure projected on the surface of the piezoelectric layer is an irregular shape, that is, a composite shape rather than a single shape.

[0127] The viewing direction of Figure 11 is consistent with the viewing direction of Figure 7. Figure 12 is an enlarged structural view of multiple reflective structures 304 in Figure 11; Figure 13 is an enlarged structural view of one reflective structure 304 in Figure 11, where Figure 11 only illustrates several reflective structures 304 and does not represent the number formed in the actual process.

[0128] First, please refer to FIG. 11 . The present invention provides a method for forming a semiconductor structure, including: providing a piezoelectric layer 300 .

[0129] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0130] Referring to FIG. 11 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0131] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0132] In other embodiments, the material of the interdigital electrodes of the IDT may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, copper, etc.

[0133] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0134] In other embodiments, the number of IDTs may be set according to actual needs.

[0135] Please refer to Figures 11 to 13, the formation method also includes: forming a plurality of reflection structures 304 between two interdigital transducers 301, the number of the reflection structures 304 ranges from 2 to 20, and the reflection structure 304 includes a plurality of first reflection parts 304a arranged along a first direction, the shape of the first reflection parts 304a projected on the surface of the piezoelectric layer 300 is an arc, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0136] In this embodiment, the first direction is set as the Y-axis direction, and the second direction is set as the X-axis direction.

[0137] It should be noted that the first direction mentioned in the specification may not be parallel to the direction of surface acoustic wave propagation between the two IDTs 301 , and the Y-axis direction in this embodiment is only a specific embodiment.

[0138] In this embodiment, the first reflective portion 304 a protrudes from the side surface of the reflective structure 304 .

[0139] In this embodiment, referring to FIG. 13 , the central angle θ1 of the first reflective portion 304 a ranges from 90° to 180°, and the radius R1 of the first reflective portion 304 a ranges from 2 μm to 10 μm.

[0140] In this embodiment, referring to FIG13 , the first reflective portions 304 a have the same size, the same central angle θ1, and the same radius R1.

[0141] In other embodiments, the sizes of the plurality of first reflective portions may be different. In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different. In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0142] In this embodiment, the plurality of first reflective portions 304 a are asymmetrically distributed about the central axis of the reflective structure 304 , and the central axis of the reflective structure 304 is parallel to the first direction.

[0143] In this embodiment, the first reflective portions 304a on both sides of the reflective structure 304 are staggered, wherein a ratio of a staggered distance M1 along the first direction to a radius R1 of the first reflective portion 304a is in a range of 0 to 2:1.

[0144] In other embodiments, the plurality of first reflective portions are symmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0145] In this embodiment, the first reflective portions 304a are spaced at the same distance in the first direction. In this embodiment, the ratio of the distance D1 between two first reflective portions 304a to the radius R1 of the first reflective portion 304a is in a range of 1:4 to 2:1.

[0146] In other embodiments, the intervals between the plurality of first reflective portions in the first direction may be different.

[0147] In this embodiment, the ratio of the distance L1 between the two side walls of the reflective structure 304 to the radius R1 of the first reflective portion 304 a ranges from 1:2 to 1:1.

[0148] In this embodiment, the sizes of the multiple reflective structures 304 are the same.

[0149] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0150] In this embodiment, the plurality of reflective structures 304 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0151] In this embodiment, the intervals between the plurality of reflective structures 304 along the first direction are different.

[0152] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0153] In this embodiment, the spacing between the plurality of reflective structures 304 along the second direction is the same.

[0154] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0155] In this embodiment, the arrangement of the plurality of reflective structures 304 is irregular.

[0156] 12 , the plurality of reflective structures 304 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 304 in each reflective structure group may be the same or different.

[0157] In this embodiment, referring to FIG. 12 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 304 in the same reflective structure group ranges from 5 microns to 10 microns.

[0158] Correspondingly, using the above-mentioned formation method, please refer to Figures 11 to 13. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and multiple reflective structures 304 located between the two interdigital transducers 301, wherein the reflective structures 304 include multiple first reflective portions 304a arranged along a first direction, and the shape of the projection of the first reflective portions 304a on the surface of the piezoelectric layer 300 is an arc, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0159] In this embodiment, the multiple reflective structures 304 are divided into multiple reflective structure groups. The multiple reflective structures 304 in the same reflective structure group are distributed along the first direction, and different reflective structure groups are arranged along the second direction.

[0160] Specifically, referring to FIG. 13 , the central angle θ1 of the first reflective portion 304 a ranges from 90° to 180°, and the radius R1 of the first reflective portion 304 a ranges from 2 μm to 10 μm.

[0161] In this embodiment, referring to FIG. 13 , the sizes of the plurality of first reflective portions 304 a are the same.

[0162] In this embodiment, the central angles θ1 of the plurality of first reflective portions 304 a are the same.

[0163] In this embodiment, the radii R1 of the plurality of first reflective portions 304 a are the same.

[0164] In other embodiments, the sizes of the multiple first reflective portions may be different.

[0165] In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different. In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0166] In this embodiment, the plurality of first reflective portions 304 a are asymmetrically distributed about the central axis of the reflective structure 304 , and the central axis of the reflective structure 304 is parallel to the first direction.

[0167] In this embodiment, the first reflective portions 304a on both sides of the reflective structure 304 are staggered, wherein a ratio of a staggered distance M1 along the first direction to a radius R1 of the first reflective portion 304a is in a range of 0 to 2:1.

[0168] In other embodiments, the plurality of first reflective portions are symmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0169] In this embodiment, the first reflective portions 304a are spaced at the same distance in the first direction. In this embodiment, the ratio of the distance D1 between two first reflective portions 304a to the radius R1 of the first reflective portion 304a is in a range of 1:4 to 2:1.

[0170] In other embodiments, the intervals between the plurality of first reflective portions in the first direction may be different.

[0171] In this embodiment, the ratio of the distance L1 between the two side walls of the reflective structure 304 to the radius R1 of the first reflective portion 304 a ranges from 1:2 to 1:1.

[0172] In this embodiment, the sizes of the multiple reflective structures 304 are the same.

[0173] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0174] In this embodiment, the plurality of reflective structures 304 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0175] In this embodiment, the intervals between the plurality of reflective structures 304 along the first direction are different.

[0176] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0177] In this embodiment, the spacing between the plurality of reflective structures 304 along the second direction is the same.

[0178] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0179] In this embodiment, the arrangement of the plurality of reflective structures 304 is irregular.

[0180] 12 , the plurality of reflective structures 304 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 304 in each reflective structure group may be the same or different.

[0181] In this embodiment, referring to FIG. 12 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 304 in the same reflective structure group ranges from 5 microns to 10 microns.

[0182] 14 to 16 are schematic diagrams showing the process structure of a method for forming a semiconductor structure according to a fourth embodiment of the present invention.

[0183] The viewing direction of Figure 14 is consistent with the viewing direction of Figure 7. Figure 15 is an enlarged structural view of multiple reflective structures 305 in Figure 14; Figure 16 is an enlarged structural view of one reflective structure 305 in Figure 14, where Figure 14 only illustrates multiple reflective structures 305 and does not represent the number formed by the actual process.

[0184] Please refer to FIG. 14 . The present invention provides a method for forming a semiconductor structure, including: providing a piezoelectric layer 300 .

[0185] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0186] Referring to FIG. 14 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0187] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0188] In other embodiments, the material of the interdigital electrodes of the IDT may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, copper, etc.

[0189] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0190] In other embodiments, the number of IDTs may be set according to actual needs.

[0191] Please refer to Figures 14 to 16, the formation method also includes: forming a plurality of reflection structures 305 between two interdigital transducers 301, the number of the reflection structures 305 ranges from 2 to 20, the reflection structure 305 includes a plurality of first reflection parts 305a arranged along a first direction, the shape of the first reflection parts 305a projected on the surface of the piezoelectric layer 300 is an arc, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0192] In this embodiment, the first direction is set as the Y-axis direction, and the second direction is set as the X-axis direction.

[0193] It should be noted that the first direction mentioned in the specification may not be parallel to the direction of surface acoustic wave propagation between the two IDTs 301 , and the Y-axis direction in this embodiment is only a specific embodiment.

[0194] In this embodiment, the first reflective portion 305 a is recessed into the side surface of the reflective structure 305 .

[0195] In this embodiment, referring to FIG. 16 , the central angle θ1 of the first reflective portion 305 a ranges from 90° to 180°, and the radius R1 of the first reflective portion 305 a ranges from 2 μm to 10 μm.

[0196] 16 , the sizes of the plurality of first reflective portions 305 a are the same. In the embodiment, the central angles θ1 of the plurality of first reflective portions 305 a are the same.

[0197] In this embodiment, the radii R1 of the plurality of first reflective portions 305 a are the same.

[0198] In other embodiments, the sizes of the multiple first reflective portions may be different.

[0199] In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different.

[0200] In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0201] In this embodiment, the plurality of first reflective portions 305a are asymmetrically distributed about the central axis of the reflective structure 305, and the central axis of the reflective structure 305 is parallel to the first direction. In this embodiment, the first reflective portions 305a on both sides of the reflective structure 305 are staggered, wherein the ratio of the staggered distance M1 along the first direction to the radius R1 of the first reflective portion 305a ranges from 0 to 2:1.

[0202] In other embodiments, the plurality of first reflective portions are symmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0203] In this embodiment, the first reflective portions 305a are spaced at the same distance in the first direction. In this embodiment, the ratio of the distance D1 between two first reflective portions 305a to the radius R1 of the first reflective portion 305a is in a range of 1:4 to 2:1.

[0204] In other embodiments, the intervals between the plurality of first reflective portions in the first direction may be different.

[0205] In this embodiment, the ratio of the distance L2 between the two side walls of the reflective structure 305 to the radius R1 of the first reflective portion 305 a ranges from 1:2 to 1:1.

[0206] In this embodiment, the sizes of the multiple reflective structures 305 are the same.

[0207] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0208] In this embodiment, the plurality of reflective structures 305 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0209] In this embodiment, the intervals between the plurality of reflective structures 305 along the first direction are different.

[0210] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0211] In this embodiment, the spacing between the plurality of reflective structures 305 along the second direction is the same.

[0212] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0213] In this embodiment, the arrangement of the plurality of reflective structures 305 is irregular.

[0214] 15 , the plurality of reflective structures 305 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 305 in each reflective structure group may be the same or different.

[0215] In this embodiment, referring to FIG. 15 , the interval d1 between adjacent reflective structure groups ranges from 5 micrometers to 10 micrometers, and the interval d2 between adjacent reflective structures 305 in the same reflective structure group ranges from 5 micrometers to 10 micrometers.

[0216] Correspondingly, using the above-mentioned formation method, please refer to Figures 14 to 16. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and multiple reflective structures 305 located between the two interdigital transducers 301, wherein the reflective structures 305 include multiple first reflective portions 305a arranged along a first direction, and the shape of the projection of the first reflective portions 305a on the surface of the piezoelectric layer 300 is an arc, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0217] In this embodiment, the multiple reflective structures 305 are divided into multiple reflective structure groups. The multiple reflective structures 305 in the same reflective structure group are distributed along the first direction, and different reflective structure groups are arranged along the second direction.

[0218] Specifically, referring to FIG. 16 , the central angle θ1 of the first reflective portion 305 a ranges from 90° to 180°, and the radius R1 of the first reflective portion 305 a ranges from 2 micrometers to 10 micrometers.

[0219] In this embodiment, referring to FIG16 , the first reflective portions 305a have the same size, the same central angle θ1, and the same radius R1.

[0220] In other embodiments, the sizes of the plurality of first reflective portions may be different. In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different. In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0221] In this embodiment, the plurality of first reflective portions 305 a are asymmetrically distributed about the central axis of the reflective structure 305 , and the central axis of the reflective structure 305 is parallel to the first direction.

[0222] In this embodiment, the first reflective portions 305a on both sides of the reflective structure 305 are staggered, wherein a ratio of a staggered distance M1 along the first direction to a radius R1 of the first reflective portion 305a is in a range of 0 to 2:1.

[0223] In other embodiments, the plurality of first reflective portions are symmetrically distributed about the central axis of the reflective structure, and the central axis of the reflective structure is parallel to the first direction.

[0224] In this embodiment, the first reflective portions 305a are spaced at the same distance in the first direction. In this embodiment, the ratio of the distance D1 between two first reflective portions 305a to the radius R1 of the first reflective portion 305a is in a range of 1:4 to 2:1.

[0225] In other embodiments, the intervals between the plurality of first reflective portions in the first direction may be different.

[0226] In this embodiment, the ratio of the distance L2 between the two side walls of the reflective structure 305 to the radius R1 of the first reflective portion 305 a ranges from 1:2 to 1:1.

[0227] In this embodiment, the sizes of the multiple reflective structures 305 are the same.

[0228] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0229] In this embodiment, the plurality of reflective structures 305 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0230] In this embodiment, the intervals between the plurality of reflective structures 305 along the first direction are different.

[0231] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0232] In this embodiment, the spacing between the plurality of reflective structures 305 along the second direction is the same.

[0233] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0234] In this embodiment, the arrangement of the plurality of reflective structures 305 is irregular.

[0235] 15 , the plurality of reflective structures 305 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 305 in each reflective structure group may be the same or different.

[0236] In this embodiment, referring to FIG. 15 , the interval d1 between adjacent reflective structure groups ranges from 5 micrometers to 10 micrometers, and the interval d2 between adjacent reflective structures 305 in the same reflective structure group ranges from 5 micrometers to 10 micrometers.

[0237] 17 to 19 are schematic diagrams showing the process structure of a method for forming a semiconductor structure according to a fifth embodiment of the present invention.

[0238] The viewing direction of Figure 17 is consistent with the viewing direction of Figure 7. Figure 18 is an enlarged structural view of multiple reflective structures 306 in Figure 17; Figure 19 is an enlarged structural view of one reflective structure 306 in Figure 17, where Figure 17 only illustrates multiple reflective structures 306 and does not represent the number formed by the actual process.

[0239] Please refer to FIG. 17 . The present invention provides a method for forming a semiconductor structure, including: providing a piezoelectric layer 300 .

[0240] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0241] Referring to FIG. 17 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0242] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0243] In other embodiments, the material of the interdigital electrodes of the IDT may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, copper, etc.

[0244] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0245] In other embodiments, the number of IDTs may be set according to actual needs.

[0246] Please refer to Figures 17 to 19. A plurality of reflection structures 306 are formed between two interdigital transducers 301. The number of the reflection structures 306 ranges from 1 to 10. The reflection structure 306 includes a plurality of first reflection portions 306a and second reflection portions 306b arranged along a first direction. The first reflection portions 306a and the second reflection portions 306b are adjacent to each other. The shape of the first reflection portion 306a projected on the surface of the piezoelectric layer 300 is an arc shape. The shape of the second reflection portion 306b projected on the surface of the piezoelectric layer 300 is an arc shape. The first direction is parallel to the surface of the piezoelectric layer 300.

[0247] In this embodiment, the first reflective portion 306 a is recessed in the side surface of the reflective structure 306 , and the second reflective portion 306 b is protruded from the side surface of the reflective structure 306 .

[0248] In this embodiment, please refer to Figure 19, the central angle θ1 of the first reflective portion 306a ranges from 90° to 180°, the radius R1 of the first reflective portion 306a ranges from 2 microns to 10 microns, the central angle θ2 of the second reflective portion 306b ranges from 90° to 180°, and the radius R2 of the second reflective portion 306b ranges from 2 microns to 10 microns.

[0249] In this embodiment, referring to FIG19 , the first reflective portions 306 a have the same size, the same central angle θ1, and the same radius R1.

[0250] In other embodiments, the sizes of the plurality of first reflective portions may be different. In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different. In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0251] In this embodiment, referring to FIG19 , the sizes of the plurality of second reflective portions 306 b are the same. In this embodiment, the central angles θ2 of the plurality of second reflective portions 306 b are the same. In this embodiment, the radius R2 of the plurality of second reflective portions 306 b are the same.

[0252] In other embodiments, the sizes of the plurality of second reflective portions may be different. In other embodiments, the central angles θ2 of the plurality of second reflective portions may be different. In other embodiments, the radii R2 of the plurality of second reflective portions may be different.

[0253] In this embodiment, multiple first reflecting portions 306a are asymmetrically distributed about the central axis of the reflecting structure 306, and multiple second reflecting portions 306b are asymmetrically distributed about the central axis of the reflecting structure 306. The central axis of the reflecting structure 306 is parallel to the first direction, wherein the ratio of the minimum spacing dimension L3 between the first reflecting portions 306a on both side walls of the reflecting structure 306 to the radius R1 of the first reflecting portion 306a is in a range of 1:2 to 1:1; and the ratio of the spacing M2 between the center points of the first reflecting portion 306a and the second reflecting portion 306b on the same side of the reflecting structure 306 in the second direction to the sum of the radius R2 of the second reflecting portion 306b and the radius R1 of the first reflecting portion 306a is in a range of 1:1 to 2:1.

[0254] In other embodiments, the first reflective portions 306a are symmetrically distributed about the central axis of the reflective structure 306, and the second reflective portions 306b are symmetrically distributed about the central axis of the reflective structure 306. The central axis of the reflective structure 306 is parallel to the first direction.

[0255] In this embodiment, the sizes of the multiple reflective structures 306 are the same.

[0256] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0257] In this embodiment, the plurality of reflective structures 306 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0258] In this embodiment, the intervals between the plurality of reflective structures 306 along the first direction are different.

[0259] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0260] In this embodiment, the spacing between the plurality of reflective structures 306 along the second direction is the same.

[0261] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0262] In this embodiment, the arrangement of the plurality of reflective structures 306 is irregular.

[0263] 18 , the plurality of reflective structures 306 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 306 in each reflective structure group may be the same or different.

[0264] In this embodiment, referring to FIG. 18 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 306 in the same reflective structure group ranges from 5 microns to 10 microns.

[0265] Correspondingly, using the above-mentioned formation method, please refer to Figures 17 to 19. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and a plurality of reflective structures 306 located between the two interdigital transducers 301, wherein the reflective structures 306 include a plurality of first reflective portions 306a and second reflective portions 306b arranged along a first direction, the first reflective portions 306a and the second reflective portions 306b are adjacent to each other, the shape of the first reflective portion 306a projected on the surface of the piezoelectric layer 300 is an arc, the shape of the second reflective portion 306b projected on the surface of the piezoelectric layer 300 is an arc, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0266] In this embodiment, the first reflective portion 306 a is recessed in the side surface of the reflective structure 306 , and the second reflective portion 306 b is protruded from the side surface of the reflective structure 306 .

[0267] In this embodiment, please refer to Figure 19, the central angle θ1 of the first reflective portion 306a ranges from 90° to 180°, the radius R1 of the first reflective portion 306a ranges from 2 microns to 10 microns, the central angle θ2 of the second reflective portion 306b ranges from 90° to 180°, and the radius R2 of the second reflective portion 306b ranges from 2 microns to 10 microns.

[0268] In this embodiment, referring to FIG19 , the first reflective portions 306 a have the same size, the same central angle θ1, and the same radius R1.

[0269] In other embodiments, the sizes of the plurality of first reflective portions may be different. In other embodiments, the central angles θ1 of the plurality of first reflective portions may be different. In other embodiments, the radii R1 of the plurality of first reflective portions may be different.

[0270] In this embodiment, referring to FIG19 , the sizes of the plurality of second reflective portions 306 b are the same. In this embodiment, the central angles θ2 of the plurality of second reflective portions 306 b are the same. In this embodiment, the radius R2 of the plurality of second reflective portions 306 b are the same.

[0271] In other embodiments, the sizes of the plurality of second reflective portions may be different. In other embodiments, the central angles θ2 of the plurality of second reflective portions may be different. In other embodiments, the radii R2 of the plurality of second reflective portions may be different.

[0272] In this embodiment, the first reflective portions 306a are asymmetrically distributed about the central axis of the reflective structure 306, and the second reflective portions 306b are asymmetrically distributed about the central axis of the reflective structure 306. The central axis of the reflective structure 306 is parallel to the first direction.

[0273] In other embodiments, the first reflective portions 306a are symmetrically distributed about the central axis of the reflective structure 306, and the second reflective portions 306b are symmetrically distributed about the central axis of the reflective structure 306. The central axis of the reflective structure 306 is parallel to the first direction.

[0274] In this embodiment, the ratio of the minimum distance L3 between the first reflective portions 306 a on both side walls of the reflective structure 306 to the radius R1 of the first reflective portion 306 a ranges from 1:2 to 1:1.

[0275] In this embodiment, the ratio of the distance M2 between the center of the first reflective portion 306a and the center of the second reflective portion 306b on the same side of the reflective structure 306 in the first direction to the sum of the radius R2 of the second reflective portion 306b and the radius R1 of the first reflective portion 306a ranges from 1:1 to 2:1.

[0276] In this embodiment, the sizes of the multiple reflective structures 306 are the same.

[0277] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0278] In this embodiment, the plurality of reflective structures 306 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0279] In this embodiment, the intervals between the plurality of reflective structures 306 along the first direction are different.

[0280] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0281] In this embodiment, the spacing between the plurality of reflective structures 306 along the second direction is the same.

[0282] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0283] In this embodiment, the arrangement of the plurality of reflective structures 306 is irregular.

[0284] 18 , the plurality of reflective structures 306 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 306 in each reflective structure group may be the same or different.

[0285] In this embodiment, referring to FIG. 18 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 306 in the same reflective structure group ranges from 5 microns to 10 microns.

[0286] 20 to 22 are schematic structural diagrams of a method for forming a semiconductor structure according to a sixth embodiment of the present invention.

[0287] The viewing direction of Figure 20 is consistent with the viewing direction of Figure 7. Figure 21 is an enlarged structural view of multiple reflective structures 307 in Figure 20; Figure 22 is an enlarged structural view of one reflective structure 307 in Figure 20, where Figure 20 only illustrates multiple reflective structures 307 and does not represent the number formed by the actual process.

[0288] Please refer to FIG. 20 . The present invention provides a method for forming a semiconductor structure, including: providing a piezoelectric layer 300 .

[0289] In this embodiment, the material of the piezoelectric layer 300 includes lithium tantalate or lithium niobate.

[0290] Referring to FIG. 20 , the forming method further includes: forming two interdigital transducers 301 on the piezoelectric layer 300 .

[0291] In this embodiment, the material of the interdigital electrodes of the IDT 301 is aluminum or aluminum alloy.

[0292] In other embodiments, the material of the interdigital electrodes of the IDT may also be a metal material or a metal alloy material such as molybdenum, tungsten, platinum, copper, etc.

[0293] In this embodiment, two interdigital transducers 301 are formed on the piezoelectric layer 300 .

[0294] In other embodiments, the number of IDTs may be set according to actual needs.

[0295] Please refer to Figures 20 to 22. The formation method also includes: forming a plurality of reflection structures 307 between two interdigital transducers 301, the number of the reflection structures 307 is greater than 2, and the reflection structure 307 includes a plurality of first reflection parts 307a arranged along a first direction, the shape of the first reflection parts 307a projected on the surface of the piezoelectric layer 300 is trapezoidal, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0296] In this embodiment, the first direction is set as the Y-axis direction, and the second direction is set as the X-axis direction.

[0297] In this embodiment, the first reflective portion 307a protrudes from the side surface of the reflective structure 307. Referring to FIG. 22 , the base angle α1 of the first reflective portion 307a ranges from 30° to 60°, the height h1 of the first reflective portion 307a ranges from 2 μm to 6 μm, and the ratio of the upper base a of the first reflective portion 307a to the height h1 of the first reflective portion 307a ranges from 1:1 to 1.5:1. In this embodiment, the height h1 is the height between the upper and lower bases of the first reflective portion 307a.

[0298] In this embodiment, the base angles α1 of the first reflective portions 307 a are the same, and the heights h1 of the first reflective portions 307 a are the same.

[0299] In other embodiments, the base angle α1 of the first reflective portion 307a may be different.

[0300] In other embodiments, the height h1 of the first reflective portion 307a may be different.

[0301] In this embodiment, the plurality of first reflective portions 307a are symmetrically distributed about the central axis of the reflective structure 307, and the central axis of the reflective structure 307 is parallel to the first direction. In this embodiment, the first reflective portions 307a on both sides of the reflective structure 307 are symmetrically arranged, wherein the plurality of first reflective portions 307a are uniformly spaced in the first direction, and the ratio of the distance D2 between two first reflective portions 307a to the height h1 of the first reflective portion 307a ranges from 1:1 to 2:1.

[0302] In this embodiment, the ratio of the distance L4 between opposite sidewalls of the reflective structure 307 to the height h1 of the first reflective portion 307 a ranges from 1:1 to 3:1.

[0303] In this embodiment, the sizes of the multiple reflective structures 307 are the same.

[0304] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0305] In this embodiment, the plurality of reflective structures 307 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0306] In this embodiment, the intervals between the plurality of reflective structures 307 along the first direction are different.

[0307] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0308] In this embodiment, the spacing between the plurality of reflective structures 307 along the second direction is the same.

[0309] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0310] In this embodiment, the arrangement of the plurality of reflective structures 307 is irregular.

[0311] 21 , the plurality of reflective structures 307 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 307 in each reflective structure group may be the same or different.

[0312] In this embodiment, referring to FIG. 21 , the interval d1 between adjacent reflective structure groups ranges from 5 micrometers to 10 micrometers, and the interval d2 between adjacent reflective structures 307 in the same reflective structure group ranges from 5 micrometers to 10 micrometers.

[0313] Correspondingly, using the above-mentioned formation method, please refer to Figures 20 to 22. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and multiple reflective structures 307 located between the two interdigital transducers 301, wherein the reflective structures 307 include multiple first reflective portions 307a arranged along a first direction, and the shape of the projection of the first reflective portions 307a on the surface of the piezoelectric layer 300 is a trapezoid, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0314] In this embodiment, the multiple reflective structures 307 are divided into multiple reflective structure groups. The multiple reflective structures 307 in the same reflective structure group are distributed along the first direction, and different reflective structure groups are arranged along the second direction.

[0315] In this embodiment, the first reflective portion 307 a protrudes from the side surface of the reflective structure 307 .

[0316] Specifically, referring to FIG22 , the base angle α1 of the first reflective portion 307a ranges from 30° to 60°, the height h1 of the first reflective portion 307a ranges from 2 μm to 6 μm, and the ratio of the upper base a of the first reflective portion 307a to the height h1 of the first reflective portion 307a is 1:1 to 1.5:1. In this embodiment, the height h1 is the height between the upper base and the lower base of the first reflective portion 307a.

[0317] In this embodiment, the base angles α1 of the first reflective portions 307 a are the same, and the heights h1 of the first reflective portions 307 a are the same.

[0318] In other embodiments, the base angle α1 of the first reflective portion 307a may be different.

[0319] In other embodiments, the height h1 of the first reflective portion 307a may be different.

[0320] In this embodiment, the plurality of first reflective portions 307a are symmetrically distributed about the central axis of the reflective structure 307, and the central axis of the reflective structure 307 is parallel to the first direction. In this embodiment, the first reflective portions 307a on both sides of the reflective structure 307 are symmetrically arranged, wherein the plurality of first reflective portions 307a are uniformly spaced in the first direction, and the ratio of the distance D2 between two first reflective portions 307a to the height h1 of the first reflective portion 307a ranges from 1:1 to 2:1.

[0321] In this embodiment, the ratio of the distance L4 between opposite sidewalls of the reflective structure 307 to the height h1 of the first reflective portion 307 a ranges from 1:1 to 3:1.

[0322] In this embodiment, the sizes of the multiple reflective structures 307 are the same.

[0323] In other embodiments, the sizes of the plurality of reflective structures are different and irregular.

[0324] In this embodiment, the plurality of reflective structures 307 are staggered along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

[0325] In this embodiment, the intervals between the plurality of reflective structures 307 along the first direction are different.

[0326] In other embodiments, the spacing between the plurality of reflective structures along the first direction is the same.

[0327] In this embodiment, the spacing between the plurality of reflective structures 307 along the second direction is the same.

[0328] In other embodiments, the intervals between the plurality of reflective structures along the second direction are different.

[0329] In this embodiment, the arrangement of the plurality of reflective structures 307 is irregular.

[0330] 21 , the plurality of reflective structures 307 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 307 in each reflective structure group may be the same or different.

[0331] In this embodiment, referring to FIG. 21 , the interval d1 between adjacent reflective structure groups ranges from 5 micrometers to 10 micrometers, and the interval d2 between adjacent reflective structures 307 in the same reflective structure group ranges from 5 micrometers to 10 micrometers.

[0332] 23 to 25 are schematic structural diagrams of a method for forming a semiconductor structure according to a seventh embodiment of the present invention.

[0333] The viewing direction of Figure 23 is consistent with the viewing direction of Figure 7. Figure 24 is an enlarged structural view of multiple reflective structures 308 in Figure 23; Figure 25 is an enlarged structural view of one reflective structure 308 in Figure 23, where Figure 23 only illustrates multiple reflective structures 308 and does not represent the number formed by the actual process.

[0334] Please refer to Figures 23 to 25. A plurality of reflective structures 308 are formed between two interdigital transducers 301. The reflective structure 308 includes a plurality of first reflective portions 308a arranged along a first direction. The shape of the first reflective portions 308a projected on the surface of the piezoelectric layer 300 is a triangle, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0335] In this embodiment, the first reflective portion 308 a protrudes from the side surface of the reflective structure 308 .

[0336] In this embodiment, referring to FIG. 25 , the first reflective portion 308 a has a reference bottom edge d4 in the first direction, a vertex angle α2 of the first reflective portion 308 a ranges from 60° to 120°, a height h2 from the vertex angle α2 to the reference bottom edge d4 ranges from 2 μm to 6 μm, and a distance between adjacent vertex angles α2 on the same side wall of the reflective structure 308 is 1 μm. Comprehensive consideration is given to the numerical values ​​in order to present a more complex reflection surface.

[0337] 25 , the sizes of the plurality of first reflective portions 308 a are the same. In the embodiment, the vertex angles α2 of the plurality of first reflective portions 308 a are the same.

[0338] In this embodiment, the heights h2 of the plurality of first reflective portions 308 a are the same, and the distances b between adjacent vertex angles α2 on the same sidewall of the reflective structure 308 are the same.

[0339] In other embodiments, the sizes of the plurality of first reflective portions may be different. In other embodiments, the top angles α2 of the plurality of first reflective portions may be different.

[0340] In other embodiments, the heights h2 of the plurality of first reflective portions may be different. In other embodiments, the distances b between adjacent vertex angles α2 on the same sidewall of the reflective structure 308 may be different.

[0341] For other features related to this embodiment, reference may be made to the above embodiments, such as the sixth embodiment, and will not be repeated here.

[0342] 24 , the plurality of reflective structures 308 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 308 in each reflective structure group may be the same or different.

[0343] In this embodiment, referring to FIG. 24 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 308 in the same reflective structure group ranges from 5 microns to 10 microns.

[0344] Correspondingly, using the above-mentioned formation method, please refer to Figures 23 to 25. The present invention also provides a semiconductor structure, including a piezoelectric layer 300; two interdigital transducers 301 located on the piezoelectric layer 300; and a plurality of reflective structures 308 located between the two interdigital transducers 301, wherein the reflective structures 308 include a plurality of first reflective portions 308a arranged along a first direction, and the shape of the projection of the first reflective portions 308a on the surface of the piezoelectric layer 300 is a triangle, and the first direction is parallel to the surface of the piezoelectric layer 300.

[0345] In this embodiment, the first reflective portion 308 a protrudes from the side surface of the reflective structure 308 .

[0346] In this embodiment, referring to FIG. 25 , the first reflective portion 308 a has a reference bottom edge d4 in the first direction, a vertex angle α2 of the first reflective portion 308 a ranges from 60° to 120°, a height h2 from the vertex angle α2 to the reference bottom edge d4 ranges from 2 μm to 6 μm, and a distance between adjacent vertex angles α2 on the same side wall of the reflective structure 308 is 1 μm. Comprehensive consideration is given to the numerical values ​​in order to present a more complex reflection surface.

[0347] In this embodiment, referring to FIG. 25 , the dimensions of the plurality of first reflective portions 308 a are identical. In this embodiment, the apex angles α2 of the plurality of first reflective portions 308 a are identical. In this embodiment, the heights h2 of the plurality of first reflective portions 308 a are identical, and the distances b between adjacent apex angles α2 on the same sidewall of the reflective structure 308 are identical.

[0348] In other embodiments, the sizes of the multiple first reflective portions may be different. In other embodiments, the vertex angles α2 of the multiple first reflective portions may be different. In other embodiments, the heights h2 of the multiple first reflective portions may be different. In other embodiments, the distances b between adjacent vertex angles α2 on the same sidewall of the reflective structure 308 may be different.

[0349] For other features related to this embodiment, reference may be made to the above embodiments, such as the sixth embodiment, and will not be repeated here.

[0350] 24 , the plurality of reflective structures 308 are divided into three groups, namely Group I, Group II, and Group III. The number of reflective structures 308 in each reflective structure group may be the same or different.

[0351] In this embodiment, referring to FIG. 24 , the interval d1 between adjacent reflective structure groups ranges from 5 microns to 10 microns, and the interval d2 between adjacent reflective structures 308 in the same reflective structure group ranges from 5 microns to 10 microns.

[0352] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A semiconductor structure, characterized in that, Comprising: A piezoelectric layer; Two interdigital transducers located on the piezoelectric layer; A plurality of reflection structures located between the two interdigital transducers, wherein at least two of the shape of the reflection structure, the size of the reflection structure, and the arrangement of the plurality of reflection structures are irregular.

2. The semiconductor structure according to claim 1, wherein, The shape of the projection of the reflection structure on the surface of the piezoelectric layer is an irregular shape.

3. The semiconductor structure according to claim 2, wherein The reflection structure includes a plurality of first reflection portions arranged along a first direction, and the shape of the projection of the first reflection portion on the surface of the piezoelectric layer includes one or more combinations of a trapezoid, a triangle, and an arc, and the first direction is parallel to the surface of the piezoelectric layer.

4. The semiconductor structure according to claim 3, wherein The first reflection portion protrudes from the side surface of the reflection structure.

5. The semiconductor structure according to claim 3, wherein, The first reflection portion is recessed from the side surface of the reflection structure.

6. The semiconductor structure according to claim 3, wherein, The plurality of first reflection portions are symmetrically distributed about the central axis of the reflection structure, and the central axis of the reflection structure is parallel to the first direction.

7. The semiconductor structure according to claim 3, wherein The plurality of first reflection portions are asymmetrically distributed about the central axis of the reflection structure, and the central axis of the reflection structure is parallel to the first direction.

8. The semiconductor structure according to claim 3, wherein, The distances between the plurality of first reflection portions in the first direction are the same.

9. The semiconductor structure according to claim 3, wherein The distances between the plurality of first reflection portions in the first direction are different.

10. The semiconductor structure according to claim 3, wherein The sizes of the plurality of first reflection portions are the same.

11. The semiconductor structure according to claim 3, wherein, The sizes of the plurality of first reflection portions are different and irregular.

12. The semiconductor structure according to claim 2, wherein, The sizes of the plurality of reflection structures are the same.

13. The semiconductor structure according to claim 2, wherein The sizes of the plurality of reflection structures are different and irregular.

14. The semiconductor structure according to claim 3, wherein The plurality of reflection structures are placed in a staggered manner along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer, and the second direction is perpendicular to the first direction.

15. The semiconductor structure according to claim 14, wherein The distances between the plurality of reflection structures in the first direction are the same.

16. The semiconductor structure according to claim 14, wherein The distances between the plurality of reflection structures in the first direction are different.

17. The semiconductor structure according to claim 14, wherein The distances between the plurality of reflection structures in the second direction are the same.

18. The semiconductor structure according to claim 14, wherein The distances between the plurality of reflection structures in the second direction are different.

19. The semiconductor structure according to claim 1, wherein, When the shape of the projection of the reflection structure on the surface of the piezoelectric layer is a regular shape, the shape of the reflection structure includes one or a combination of a circle and a polygon.

20. The semiconductor structure according to claim 19, wherein The sizes of the plurality of reflection structures are different and irregular.

21. The semiconductor structure according to claim 19, wherein, The distances between the plurality of reflection structures in a third direction are different, and the third direction is parallel to the surface of the piezoelectric layer.

22. The semiconductor structure according to claim 21, wherein, The distances between the plurality of reflection structures in a fourth direction are different, the fourth direction is parallel to the surface of the piezoelectric layer, and the fourth direction is perpendicular to the third direction.

23. A method for forming a semiconductor structure, characterized in that, Comprising: Providing a piezoelectric layer; Forming two interdigital transducers on the surface of the piezoelectric layer; Forming a plurality of reflection structures on the surface of the piezoelectric layer between the two interdigital transducers, wherein at least two of the shape of the reflection structure, the size of the reflection structure, and the arrangement of the plurality of reflection structures are irregular.

24. The method for forming a semiconductor structure according to claim 23, wherein, The shape of the projection of the reflection structure on the surface of the piezoelectric layer is an irregular shape.

25. The method for forming a semiconductor structure according to claim 24, wherein, The reflection structure includes a plurality of first reflection portions arranged along a first direction, and the shape of the projection of the first reflection portion on the surface of the piezoelectric layer includes one or more combinations of a trapezoid, a triangle, and an arc, and the first direction is parallel to the surface of the piezoelectric layer.

26. The method for forming a semiconductor structure according to claim 24, wherein The sizes of the plurality of reflection structures are the same.

27. The method for forming a semiconductor structure according to claim 24, wherein, The sizes of the multiple reflection structures are different and irregular.

28. The method for forming a semiconductor structure according to claim 25, wherein, The multiple reflection structures are placed with a dislocation along a second direction, wherein the second direction is parallel to the surface of the piezoelectric layer and perpendicular to the first direction.

29. The method for forming a semiconductor structure according to claim 23, wherein, When the shape of the projection of the reflection structure on the surface of the piezoelectric layer is a regular shape, the shape of the reflection structure includes one or a combination of a circle and a polygon.

30. The method for forming a semiconductor structure according to claim 29, wherein, The sizes of the multiple reflection structures are different and irregular.

31. The method for forming a semiconductor structure according to claim 29, wherein, The intervals of the multiple reflection structures along a third direction are different, and the third direction is parallel to the surface of the piezoelectric layer.

32. The method for forming a semiconductor structure as described in claim 31, wherein, The intervals of the multiple reflection structures along a fourth direction are different, the fourth direction is parallel to the surface of the piezoelectric layer, and the fourth direction is perpendicular to the third direction.

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