KR100857935B1 - Method of manufacturing an acoustic mirror for a piezoelectric resonator and method of manufacturing a piezoelectric resonator - Google Patents

Abstract

A mirror for a piezoelectric resonator composed of alternating layers of high acoustic impedance and low acoustic impedance is produced by creating a second layer 106a ₁ , 106a _{2 on} the first layer 106b ₁ , 106b ₂ . The second layer 106a ₁ , 106a ₂ partially covers the first layer 106b ₁ , 106b ₂ . Next, a planarization layer 132 is applied on the first layers 106b ₁ , 106b ₂ and the second layers 106a ₁ , 106a ₂ . Subsequently, the regions 134 of the second layers 106a ₁ , 106a ₂ are exposed by structuring the planarization layer 132, where this region is associated with the active region 122 of the piezoelectric resonator. Finally, the resulting structure is planarized by removing regions 132a and 132b of planarization layer 132 that remain outside of this region.

Description

METHOD OF MANUFACTURING AN ACOUSTIC MIRROR FOR A PIEZOELECTRIC RESONATOR AND METHOD OF MANUFACTURING A PIEZOELECTRIC RESONATOR}

1 shows a first example of an SMR with a mirror structured according to the prior art;

2 shows a second example of an SMR having a mirror structured according to the prior art;

3a to 3g show the steps of producing a very flat acoustic mirror according to the invention,

4A-4J illustrate the inventive processing of an acoustic mirror having two conductive layers by a plurality of deposition, structuring and planarization steps in accordance with a first preferred embodiment;

5A-5E illustrate the inventive processing of an acoustic mirror having two conductive layers by common structuring and planarization of all mirror layers in accordance with a second preferred embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

100: substrate 102: lower surface of the substrate

104: upper surface of the substrate 106: layer alignment of the mirror

106a: layer with high acoustic impedance

106a ₁ , 106a ₂ : layer with high acoustic impedance

106b: layer with low acoustic impedance

106b ₁ , 106b ₂ : Layer with low acoustic impedance

108: insulating layer 110: lower electrode

112: piezoelectric layer 114: insulating layer

116a, 116b: open area in insulating layer 114

118: upper electrode 118a, 118b: upper electrode

120a, 120b: tuning layer 122: BAW resonator

122a, 122b: BAW resonator 124: oxide layer

126: settlement 128: insulating layer

130: key phase 132: planarization layer

132a, 132b: Ridge of the planarization layer 134: Open area of the planarization layer

136: surface of the first 106a ₁ 138: surface of the planarization layer

140: floor

TECHNICAL FIELD The present invention relates to the field of piezoelectric resonators, such as, for example, bulk acoustic wave resonators, and more particularly, to a method of manufacturing a piezoelectric resonator and a method of manufacturing an acoustic mirror for a piezoelectric resonator. In particular, the present invention relates to a method of making an acoustic mirror which is very flat and has excellent uniformity in layer deposition and a planar surface in the entire mirror structure.

Radio frequency filters based on BAW resonators are very important for a variety of radio-frequency (RF) applications. In practice, there are two concepts of BAW resonators: so-called thin film BAW resonators (FBARs) and so-called solidly mounted resonators (SMR). The thin film BAW resonator includes a membrane on which it is arranged a layer arrangement consisting of a lower electrode, a piezoelectric layer and an upper electrode. Acoustic resonators operate by reflections on the top and bottom surfaces of the membrane. In another concept of SMR, an SMR includes a substrate, such as, for example, a silicon substrate, with a layer alignment consisting of a lower electrode, a piezoelectric layer, and an upper electrode disposed thereon. In this design, so-called acoustic mirrors are required to keep acoustic waves in the active region. It is located between the active layers, ie the two electrodes and the piezoelectric layer and the substrate. The acoustic mirrors are each composed of alternating layers of alternating layers with high and low acoustic impedances, such as, for example, tungsten layers (high acoustic impedance) and oxide layers (low acoustic impedance).

If the mirror comprises a layer of conductive material, such as tungsten, it is proposed to structure (pattern) the corresponding mirror layer and substantially limit it to the bottom of the active resonator region to prevent parasitic capacitance in the filter. The disadvantage of this procedure is that the phase exhibited by it can no longer be completely flattened. Because of the nonuniformity, unwanted modes can be induced in the resonator and / or degradation of the resonator can occur. This problem has hitherto been very fatal because already a small step or the remaining few percent phase of the layer thickness significantly affects the mode of operation of this resonator.

1 and 2, two known methods of making acoustic mirrors for piezoelectric or BAW resonators have been described in more detail.

1 shows an SMR in which a mirror is configured. The resonator includes a substrate 100 having a bottom surface 102 and a top surface 104. The layer alignment 106 forming the acoustic mirror is disposed on the top surface. Between the substrate and the mirror, for example, one or more intermediate layers can be arranged for reducing pressure or increasing adhesion. The layer alignment alternately includes a layer 106a having a high acoustic impedance and a layer 106b having a low acoustic impedance, where an intermediate layer can be provided between these mirror layers. On the top surface 104 of the substrate 100, a first layer 106b ₁ having a low acoustic impedance is provided. On layer 106b ₁ , materials 106a ₁ , 106a ₂ with high acoustic impedance are deposited and structured in portions associated with the active region of the resonator. On this arrangement, a second layer 106b ₂ with low acoustic impedance is deposited, and on top of it the material 106a ₃ , 106a ₄ with high acoustic impedance is partially deposited and structured. On top of this layer alignment, a layer 106b ₃ having a low acoustic impedance is again deposited. On the resulting mirror structure, the bottom electrode 110 is at least partially formed, on which the active or piezoelectric layer 112, for example AlN, is placed again. On the piezoelectric layer 112, an insulating layer 114 is formed to cover the piezoelectric layer 112 except for the regions 116a and 116b. Two upper electrodes 118a and 118b in contact with the piezoelectric layers in the regions 116a and 116b are formed on the piezoelectric layer. The tuning layers 120a, 120b are at least partially disposed on the top electrodes 118, a, 118b, by which the resonant frequency of the resonator can be adjusted. Two BAW resonators 122a and 122b are defined by the region of the upper electrodes 118a and 118b to which the piezoelectric layer 112 and the lower electrode 110 which is the lower region thereof are connected at their lower ends. The mirror structure 106 shown in FIG. 1 includes lambda / 4 mirror layers 106a and 160b.

In the example of SMR shown in FIG. 1, as produced by Epcos AG, for example, the metal layer 106a can be configured without planarization of the resulting phase. Layer 106b having low acoustic impedance is deposited over layer 106a configured as described above. Thus, the steps shown in FIG. 1 proceed, with the deposition of the layers located thereon continuing. This procedure is disadvantageous in terms of reduced piezoelectric connection of the active layer 112 as well as increased excitation of the resulting strong phase in the layer disposed above the mirror 106, especially the unwanted vibration mode.

2 shows another example of a known prior art for SMR with mirrors configured. In FIG. 2, the substrate 100 is shown again, and an oxide layer 124 is deposited on its upper surface 104, forming a pit or settlement 126 therein. In addition, an intermediate layer may be provided between the oxide layer 124 and the substrate 100. Within the pit 126, an acoustic mirror composed of a layer alignment comprising a first layer 106a ₁ having a high acoustic impedance, a layer 106b having a low acoustic impedance and a layer 160a ₂ having a high acoustic impedance is Is formed. An insulating layer 108 is deposited on the surface of the resulting structure, on top of which a lower electrode 110 is at least partially formed. An area of the insulating layer 108 not covered by the lower electrode 110 is covered by another insulating layer 128. The piezoelectric layer 112 is formed on the insulating layer 128 and the lower electrode 110, and the upper electrode 118 is partially formed on the surface thereof. A portion of the top electrode 118 and the area of the piezoelectric layer 112 not covered by the top electrode 118 are covered by the passivation layer 114. The overlapping portions of the bottom electrode 110, piezoelectric layer 112 and top electrode 118 define a BAW resonator 122.

In the example shown in FIG. 2, the pit 126 in which mirror layers 106a and 106b are sequentially deposited as described above in the region of resonator 122 to be created is etched into oxide layer 124. This is the outer layer of the mirror pit 126 is removed by one or more CMP processes, as described, for example, in US 2002/154425 A1.

The method described based on FIG. 2 shows that the layers are slightly thinner at the corners of the mirror pit 126, and the fine key phase 130 in the resonator region 122 has been developed to again increase the excitation of the unwanted mode and improve the resonator quality. It is disadvantageous in that it can be reduced.

Starting from the prior art, it is an object of the present invention to provide a method for producing an acoustic mirror for an piezoelectric resonator that allows for mirrors in which the entire mirror structure is a planar surface with good uniformity in layer deposition.

According to a first aspect, the present invention provides a method of manufacturing an acoustic mirror in which a high acoustic impedance and a low acoustic impedance layer are alternately arranged, which is preferable for an acoustic resonator, the mirror comprising at least one layer having a high acoustic impedance and (A) creating a first layer of layer alignment, and (b) layer alignment on the first layer to partially cover the first layer, comprising layer alignment of at least one layer having a low acoustic impedance Creating a second layer, (c) applying a planarization layer on the first and second layers, and (d) exposing an area of the second layer by structuring the planarization layer—a second layer. The region of is associated with the active region of the piezoelectric resonator-and (e) planarizing the structure from step (d) by removing the region of the planarization layer remaining outside of this region.

According to a second aspect, the present invention provides a method of manufacturing an acoustic mirror in which a high acoustic impedance and a low acoustic impedance layer are alternately arranged, which is preferable for an acoustic resonator, wherein the mirror comprises a plurality of layers having a high acoustic impedance and low (A) alternatingly creating a first layer (106b ₁ , 106b ₂ ) and a second layer, with alternating layer arrangements of a plurality of layers having an acoustic impedance, and (b) in step (a) Applying a planarization layer on the resulting structure, (c) exposing a region of the top second layer, wherein the region of the top second layer is associated with the active region of the piezoelectric resonator; and (d) outside of the region Planarizing the structure from step (c) by removing regions of the planarization layer remaining in the substrate.

According to a third aspect, the present invention provides a method of manufacturing a piezoelectric resonator, which method comprises (a) an acoustic mirror of a layer in which a high acoustic impedance and a low acoustic impedance layer are alternately arranged, preferably for an acoustic resonator. And having a layer alignment of at least one layer having an acoustic impedance and at least one layer having a low acoustic impedance, the step comprising (a.1) generating a first layer of layer alignment. (A.2) creating a second layer of layer alignment on the first layer to partially cover the first layer, and (a.3) a planarization layer on the first layer and the second layer Applying (a.4) exposing a region of the second layer by structuring the planarization layer, the region of the second layer being associated with an active region of the piezoelectric resonator, and (a.5) outside of the region From step (a.4) by removing the area of the remaining planarization layer Planarizing the body, comprising: (b) generating a bottom electrode at least partially on substantially the acoustic mirror, (c) generating a piezoelectric layer at least partially on the bottom electrode, and (d) Generating an upper electrode at least partially on the piezoelectric layer, wherein the region where the upper electrode, the piezoelectric layer and the lower electrode overlap, defines an active region of the piezoelectric resonator.

According to a fourth aspect, the present invention provides a method for manufacturing a piezoelectric resonator, comprising: (a) a plurality of layers having a high acoustic impedance and a low acoustic impedance layer and a plurality of layers having a low acoustic impedance and a low acoustic impedance; Including alternating layer arrangements of a plurality of layers having impedances, the steps comprising: (a.1) alternatingly generating the first layers 106b ₁ , 106b ₂ and the second layer; (A.2) applying a planarization layer on the structure produced in step (a.1), and (a.3) exposing the region of the topmost layer by structuring the planarization layer—topmost The area of the second layer is associated with the active area of the piezoelectric resonator-and (a.4) planarizing the structure from step (a.3) by removing the area of the planarization layer remaining outside of the area; (b) substantially at least partially on the acoustic mirror Generating a secondary electrode, (c) generating a piezoelectric layer at least partially on the lower electrode, and (d) generating an upper electrode at least partially on the piezoelectric layer, wherein the top electrode, piezoelectric The region where the layer and the bottom electrode overlap defines the active region of the piezoelectric resonator.

The method of the present invention enables the production of very flat acoustic mirrors and produces mirrors that ensure both good uniformity in layer deposition and flat surfaces of the entire mirror structure. Thus, according to the invention, an optimum deposition of the layer located under the mirror is possible, in particular this shows good connection of the piezoelectric layer. In addition, according to the invention, a very uniform layer distribution is obtained in the mirror, which leads to a high quality resonator and minimizes the excitation of the unwanted vibration mode.

According to the invention, the acoustic mirror is manufactured by a new combination of deposition, structuring (patterning) and planarization steps. To this end, according to the invention, one or more layers of the mirror are structured, and then the planarization layer is deposited over the whole area and opened by an etching process in the resonator area. The resonator region is the region of the mirror relative to the active region of the piezoelectric resonator, in which the region to be opened is actually chosen larger than in the case of the subsequent active resonator region, due to the etching side not exactly orthogonal to the adjustment error. Then, in accordance with the present invention, the ridges remaining in the overlapped areas are removed by a planarization process such as, for example, the CMP method, in which, according to a preferred embodiment of the present invention, the aforementioned steps are carried out in an acoustic mirror. It is repeated several times depending on the number of layers to be implemented.

According to the present invention, in order to open the planarization layer in the critical region, an optional etching process is used based on the material of the top layer of the mirror structure, ie this top layer serves as an etch stop layer. According to the present invention, this etching process retains most of the phase developed in the deposition, and thus the very flat acoustic mirror structure of the present invention has the advantage that it is reliably obtained within the critical region of a BAW resonator or piezoelectric resonator.

The very flat shape of the mirror does not appear only from the etching procedure. As mentioned above, since the deposition rate at the corners of the mirror pitch is different from the velocity at the center, an already uneven phase appears in the deposition in the method according to FIG. 2. In addition, a fine key phase is created at the center when mechanical polishing is performed. It is a fundamental core of the present invention that all deposition takes place on a flat base (and therefore no phase develops within the deposition), wherein the planarization step is chosen so as not to create a fundamental phase in the layer in the resonator region.

Preferably, the second layer to be structured is a conductive layer. The mirror layer described in connection with the present invention may be divided into a conductive / non-conductive or non-insulating / insulating layer, or a layer having a low acoustic impedance or a high acoustic impedance. When using a conductive layer, because of the parasitic electrical connection, this is structured independently of whether they have higher or lower acoustic impedance. Semiconductive layers can also be used.

According to a first preferred embodiment of the invention, the layer with high acoustic impedance is a conductive layer, the structuring and planarizing steps of which are performed for each conductive layer of the mirror structure. In the case of a mirror with two conductive layers, all the layers up to the first conductive layer are first deposited. This is then structured and planarized, and then all the layers up to the second conductive layer are deposited and structured and planarized again (FIG. 3).

In a second embodiment of the invention, all the layers of the mirror are first deposited and the conductive layer is structured and planarized with the non-conductive layers located between them. This has the advantage that, in contrast to the first preferred embodiment, only two lithography steps are required, regardless of the number of conductive layers. However, the first embodiment requires two lithographic steps for each of the conductive layers to be structured and planarized. However, the etching process is more concentrated and planarization is more difficult because of the higher steps.

In addition, by depositing an etch stop layer under the conductive layer, the uniformity / reproducibility of the etch stop can be improved using an optional etch process.

Preferably, the etching process is performed using a resist mask or a hard mask, and in the second embodiment it is necessary to use a hard mask because of the longer etching time.

In the above-described embodiment, the plurality of layers may be implemented in one etching process in one chamber or in several successive etching processes in several chambers.

In the first embodiment described above, all of the conductive layers are individually structured and planarized, and the same or different masks can be used to produce layers of substantially the same or different size. In the latter case, for example, a mirror structure in the form of a horn or a pyramid may be produced.

According to another embodiment, the present invention provides a method of manufacturing a piezoelectric resonator, wherein a first acoustic mirror according to the present invention is produced, and then a lower electrode is produced on the acoustic mirror. A piezoelectric layer is at least partially created on this lower electrode, and an upper electrode is created at least partially on the top surface of the piezoelectric layer. The region in which the upper electrode, piezoelectric layer and lower electrode overlap, defines the active region of the piezoelectric resonator. Also, prior to producing the lower electrode, one or more layers with suitable acoustic impedance may be applied and provided on the resulting acoustic mirror, wherein the lower electrode is created on this layer. In particular, this layer acts as an insulating layer when the topmost layer in the mirror structure is a conductive layer, and has any acoustic properties such as dispersion characteristics of the stack, resonance frequency or temperature course in other modes (shear wave mode). It acts as a layer to coordinate. One layer or a plurality of layers having different materials and different layer thicknesses may be provided.

The present invention also provides a method of making a connected acoustic resonator. Such resonators are arranged perpendicular to the top of each other, ie the active regions of the resonators (bottom electrode, piezoelectric layer, upper electrode) are present twice, separated by one or more intermediate layers, through which the strength of the acoustic connection can be adjusted. . The entire stack is located on the acoustic mirror, like individual resonators.

These and other aspects of the features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

In the following description of the preferred embodiment of the invention, the same or similar operating elements have been given the same reference numerals.

In the following description, it is assumed that the layer to be constructed has a higher acoustic impedance. The present invention is not limited to this embodiment, and the method of the present invention operates in a rather completely similar manner when the conductive layer has a smaller acoustic impedance.

Based on FIG. 3, the concepts underlying the present invention will be described in more detail. In FIG. 3A, a substrate 100 is shown, with a first layer 106b ₁ having a low acoustic impedance, for example an oxide, disposed on the top surface 104 of the substrate, for example a tungsten layer or Another suitable conductive layer and a first layer 106a ₁ having high acoustic impedance was deposited over the entire area. In addition, as described above, one or more intermediate layers have been provided between the substrate and the mirror or between the mirror layers. Using a hard mask or resist mask, the structure shown in FIG. 3A undergoes a structuring process whereby a first conductive layer 106a ₁ having a high acoustic impedance is constructed in the form shown in FIG. 3B.

Then, on the structure shown in FIG. 3B, a planarization layer 132 is deposited over the entire area, which is shown in FIG. 3C. The planarization layer 132 is structured using a suitable mask, such as, for example, a resist mask or a hard mask, to define the area of the planarization layer 132 to be removed in the subsequent etching process.

The appearance of the structure shown in FIG. 3C after the masking and etching process is shown in FIG. 3D. The planarization layer 132 is removed from the region 134 to expose the surface 136 of the first layer 106a ₁ with high acoustic impedance, and the ridges 132a and 132b of the planarization layer 132. Only remains in the surrounding area. The region 134 comprises at least the active region of the piezoelectric resonator in which the mirror to be produced is used together, which is generally larger than the active region of the piezoelectric resonator, which actually appears later, due to adjustment errors and oblique eching flanks. 134) is chosen slightly more.

The structure shown in FIG. 3D undergoes a planarization process such that ridges 132a and 132b are removed, for example, by a CMP process. The structure after planarization is shown in FIG. 3E, which has a flat surface, wherein the surface 136 of the first layer 106a ₁ is disposed on the first layer 106b ₁ having a low acoustic impedance. It is substantially the same height as the area surface 138 of the planarization layer 132.

Subsequently, the steps shown based on FIGS. 3A-3E are repeated, with the high acoustic impedance layers 106a ₁ , 106a ₂ and the layers 106b ₁ , 106b ₂ with low acoustic impedance, shown in FIG. 3F. The structure appears.

On the structure shown in FIG. 3F, one or more layers 140 are deposited for insulation or to adjust any acoustic properties when the top layer in the mirror structure is a conductive layer, which is shown in FIG. 3G. In order to produce a BAW resonator, an upper electrode, a lower electrode and a piezoelectric layer can be deposited on this structure, for example in the method described based on FIG. 2. In addition, an intermediate layer can be applied on this resonator, and another resonator structure is created thereon to produce two connected resonators.

Based on FIG. 4, the inventive processing of the acoustic mirror having two conductive layers will be described in more detail through a first preferred embodiment of the present invention, namely a plurality of deposition, structuring and planarization steps.

The sequential steps shown in FIGS. 4A-4E correspond to the sequential steps described based on FIGS. 3A-3E so that a new description thereof is omitted. A second layer 106a ₂ having a high acoustic impedance, for example a tungsten layer or other suitable metal layer, is then deposited over the entire area of the structure shown in FIG. 4E, which is shown in FIG. 4F. Using the process described above, layer 106a ₂ is structured to reveal the structure shown in FIG. 4G. Another planarization layer 132 is then deposited on this structure, which is shown in FIG. 4H. This is again structured, and the region 134 is opened by the etching step to expose the surface 136 of the layer 106a ₂ .

Again, ridges 132a and 132b remain as shown in FIG. 4I. After the planarization of the structure shown in FIG. 4I, a structure with the flat surface shown in FIG. 4J, that is, a structure whose surface 136 and the surface 138 are substantially the same height, is shown.

Based on Fig. 5, a second preferred embodiment of the present invention, namely the processing of an acoustic mirror having two conductive layers through common structuring and planarization of all conductive mirror layers will be described in more detail below.

In FIG. 5A, a substrate 100 is shown, with an insulating layer 108 disposed on the top surface 104 of the substrate. Unlike the embodiment described above, the first layer 106b ₁ with low acoustic impedance, the first layer 106a _{1 with} high acoustic impedance, the additional layer 106b ₂ with low acoustic impedance and the high acoustic A layer arrangement consisting of an additional layer 106a ₂ having an impedance was created as shown in FIG. 5A on the surface 104 of the substrate 100 according to the second embodiment of the present invention.

The structure shown in FIG. 5A then undergoes a structuring process, with the bottom layer 106b ₁ not being structured. By conventional masking and etching steps, the layer alignment of layers 106a ₁ , 106b ₂ , 106a ₂ is given to the desired structure, as shown in FIG. 5B. A planarization layer 132 is deposited over this layer to reveal the structure shown in FIG. 5C. Similar to the previous embodiment, the structure of the layer 132 occurs such that the top surface of the second layer 106a ₂ with high acoustic impedance occurs, and only the ridges 132a and 132b, as shown in FIG. 5D. Will remain. In the subsequent planarization step, the ridges 132a and 132b are removed to reveal the structure shown in FIG. 5E.

To complete the processing of the piezoelectric resonator device, a lower electrode, a piezoelectric layer and an upper electrode can be applied on the structure shown in FIG. 5E, such as the structure shown in FIG. 4J, which has already been described based on FIG. 3.

Although the above-described acoustic mirror according to a preferred embodiment of the present invention includes a layer having a high acoustic impedance, such as, for example, a metal layer as a top layer, the present invention is not limited to this mirror structure. Rather, by the inventive method, a mirror structure can also be produced whose top layer is a layer with low acoustic impedance. Also, a tungsten layer is mentioned as a layer with high acoustic impedance, and an oxide layer is mentioned as a layer with low acoustic impedance. However, the present invention is not limited to these materials, and other materials having high acoustic impedance or low acoustic impedance, conductive or non-conductive materials may equally be used.

As mentioned above, the structured mirror layer can have a variety of sizes such that a pyramidal horn structure appears. In principle, however, the layout of the resonator / mirror can be of any shape (eg trapezoidal), which results in an interesting shape for the three-dimensional mirror. In principle, it is rather preferable that the resonator is not circular or rectangular, since the regular form has many additional vibration modes (mostly unwanted) of similar resonance frequencies.

However, it will be appreciated that with respect to the subject matter of the present invention, the shape of the resonator / mirror is not important. Thus the structured layers may all have the same size or not (ie, cubic or pyramidal or equivalents thereof).

The invention is also independent of the thickness of the layer in the mirror. Acoustic mirrors are generally not λ / 4 mirrors because of the variety of modes and wave types (horizontal / longwave). For this reason, it is most advantageous to produce layer structures that are not periodic, ie each layer has a different thickness.

The foregoing description of the preferred embodiment substantially relates to acoustically or electrically related layers in the mirror. However, other layers or intermediate layers may be provided in addition to these layers. For example, within the mirror structure and the resonator structure disposed thereon, one or more interlayers, structured or not, may serve as etch stop layers and / or adhesion-enhancing layers. In addition, these intermediate layers may serve to influence other acoustic properties of the mirror, resonator structure or the overall structure. In addition, one or more structured or unstructured layers, such as, for example, tuning layers and / or passivation layers, may be applied on the resonator structure or on the overall structure, which further influence the acoustic properties of the protective and / or overall structure. have.

According to the present invention, there is provided a method of making an acoustic mirror for an piezoelectric resonator that allows for mirrors in which the entire mirror structure is a planar surface with good uniformity in layer deposition.

Claims (26)

In the manufacturing method of the acoustic mirror 106 in which the high acoustic impedance layer and the low acoustic impedance layer are alternately arranged, The acoustic mirror comprises a layer arrangement of at least one layer 106a ₁ , 106a _{2 with} the high acoustic impedance and at least one layer 106b ₁ , 106b ₂ with the low acoustic impedance, (a) creating a first layer 106b ₁ , 106b ₂ of the layer alignment, (b) creating a second layer (106a ₁ , 106a ₂ ) on the first layer (106b ₁ , 106b ₂ ) to partially cover the first layer (106b ₁ , 106b ₂ ), (c) applying a planarization layer 132 on the first layers 106b ₁ , 106b ₂ and the second layers 106a ₁ , 106a ₂ ; (d) said second layer (106a _1, 106a ₂₎ exposing area 134 of-the exposed region 134 of the second layer (106a _1, 106a ₂₎ is an active region of the piezoelectric resonators ( Associated with 122) (e) said second layer (106a _1, 106a ₂₎ above by remaining on the outside of the exposed region 134 to remove at least a portion of the planarization layer 132 and the second layer (106a _1, 106a ₂₎ of Planarizing the surface 136 of and the height of the surface 138 of the planarization layer 132 applied on the first layer 106b ₁ , 106b ₂ to be substantially equal. Method of making an acoustic mirror. The method of claim 1, The second layers 106a ₁ , 106a ₂ are conductive layers Method of making an acoustic mirror. The method of claim 1, The acoustic mirror includes a plurality of first layers 106b ₁ , 106b ₂ and a plurality of second layers 106a ₁ , 106a ₂ , The method of manufacturing the acoustic mirror includes repeating steps (a) to (e) for each successive first layer 106b ₁ , 106b ₂ and the second layer 106a ₁ , 106a ₂ . Containing Method of making an acoustic mirror. The method of claim 3, wherein Said step (b) comprises structuring said second layer 106a ₁ , 106a ₂ , The plurality of second layers 106a ₁ , 106a ₂ are structured using substantially the same mask to produce a structured second layer 106a ₁ , 106a ₂ having the same dimension. Method of making an acoustic mirror. The method of claim 3, wherein Said step (b) comprises structuring said second layer 106a ₁ , 106a ₂ , In order to create a predetermined type of acoustic mirror, the plurality of second layers 106a ₁ , 106a ₂ are structured using different masks. Method of making an acoustic mirror. The method of claim 5, wherein The predetermined form of acoustic mirror includes a truncated cone or an angular truncated cone. Method of making an acoustic mirror. The method of claim 1, The step (d) further comprises the step of structuring the planarization layer 132 using a mask. Method of making an acoustic mirror. The method of claim 7, wherein The mask includes a resist mask or a hard mask Method of making an acoustic mirror. The method of claim 1, Further comprising applying an etch stop layer on the first layer 106b ₁ , 106b ₂ prior to providing the second layer. Method of making an acoustic mirror. The method of claim 1, The first layers 106b ₁ , 106b ₂ are non-conductive layers, and the second layers 106a ₁ , 106a ₂ are conductive layers. Method of making an acoustic mirror. The method of claim 1, The first layer 106b ₁ , 106b ₂ is an oxide layer, and the second layer 106a ₁ , 106a ₂ is a tungsten layer. Method of making an acoustic mirror. delete In the manufacturing method of the acoustic mirror 106 in which the high acoustic impedance layer and the low acoustic impedance layer are alternately arranged, The acoustic mirror includes an alternating layer arrangement of a plurality of layers with the high acoustic impedance and a plurality of layers with the low acoustic impedance, (a) alternatingly generating the first layers 106b ₁ , 106b ₂ and the second layers 106a ₁ , 106a ₂ , (b) applying the planarization layer 132 to the structure produced in step (a), (c) top of the exposing area 134 of the second layer (106a _1, 106a ₂₎ - the area 134 is the active region of the piezoelectric resonator of the top of the second layer _{(106a 1, 106a 2) (} 122 )-With, (d) removing at least a portion of the planarization layer 132 remaining outside of the region 134 to remove the surface 136 and the first layer 106b ₁ , of the second layer 106a ₁ , 106a ₂ . Planarizing such that the height of the surface 138 of the planarization layer 132 applied on 106b ₂ ) is substantially the same. Method of making an acoustic mirror. The method of claim 13, The uppermost second layer 106a ₁ , 106a ₂ is a conductive layer Method of making an acoustic mirror. The method of claim 13, Step (c) further comprises structuring the planarization layer 132 using a mask. Method of making an acoustic mirror. The method of claim 15, The mask includes a resist mask or a hard mask Method of making an acoustic mirror. The method of claim 13, The step (a) further comprises applying an etch stop layer to the lowest first layer 106b ₁ , 106b ₂ . Method of making an acoustic mirror. The method of claim 13, The first layer 106b ₁ , 106b ₂ comprises a non-conductive layer, The second layer 106a ₁ , 106a ₂ includes a conductive layer Method of making an acoustic mirror. The method of claim 13, The first layer 106b ₁ , 106b ₂ includes an oxide layer, The second layer 106a ₁ , 106a ₂ comprises a tungsten layer Method of making an acoustic mirror. delete In the manufacturing method of the piezoelectric resonator, (a) an acoustic mirror 106 in which a high acoustic impedance layer and a low acoustic impedance layer are alternately disposed, the layer arrangement of at least one layer having the high acoustic impedance and at least one layer having the low acoustic impedance -Generating steps, which step (a.1) creating a first layer 106b ₁ , 106b ₂ of the layer alignment, (a.2) Create a second layer 106a ₁ , 106a ₂ of the layer alignment on the first layer 106b ₁ , 106b ₂ to partially cover the first layer 106b ₁ , 106b ₂ . To do that, (a.3) applying a planarization layer 132 on the first layer 106b ₁ , 106b ₂ and the second layer 106a ₁ , 106a ₂ , (a.4) exposing the region 134 of the second layer 106a ₁ , 106a ₂ by structuring the planarization layer 132—the region of the second layer 106a ₁ , 106a ₂ . 134 is associated with the active region 122 of the piezoelectric resonator; (a.5) the surface 136 and the first layer of the second layer 106a ₁ , 106a ₂ by removing at least a portion of the planarization layer 132 remaining outside of the exposed area 134. Planarization is performed such that the height of the surface 138 of the planarization layer 132 applied on (106b ₁ , 106b ₂ ) is substantially the same, (b) substantially producing the lower electrode 110 at least partially on the acoustic mirror 106; (c) forming a piezoelectric layer 112 at least partially on the lower electrode 110; (d) generating an upper electrode 118 at least partially on the piezoelectric layer 112, The region in which the upper electrode 118, the piezoelectric layer 112, and the lower electrode 110 overlap each other defines an active region 122 of the piezoelectric resonator. Method of making piezoelectric resonators. The method of claim 21, Prior to generating the lower electrode 110, further comprising providing one or more layers 140 to separate or adjust other acoustic characteristics of the resonator on the acoustic mirror 106, The lower electrode 110 is formed on the one or more layers 140. Method of making piezoelectric resonators. The method of claim 21, (e) creating an intermediate layer on the structure from step (d); Repeating steps (b) to (c) to produce additional resonator structures on the intermediate layer. Method of making piezoelectric resonators. In the manufacturing method of the piezoelectric resonator, (a) an acoustic mirror 106 of a layer of alternating high acoustic impedance and low acoustic impedance layers, the alternating layer arrangement of the plurality of layers having the high acoustic impedance and the plurality of layers having the low acoustic impedance Includes the step of generating At this stage (a.1) alternatingly generating the first layers 106b ₁ , 106b ₂ and the second layers 106a ₁ , 106a ₂ , (a.2) applying the planarization layer 132 on the structure produced in step (a.1), (a.3) exposing the region 134 of the top second layer 106a ₁ , 106a ₂ by structuring the planarization layer 132-the region of the top second layer 106a ₁ , 106a ₂ . 134 is associated with the active region 122 of the piezoelectric resonator; (a.4) removing the areas 132a and 132b of the planarization layer 132 remaining outside of the area so that the surface 136 of the second layer 106a ₁ , 106a ₂ and the first layer ( Planarizing such that the height of the surface 138 of the planarization layer 132 applied on 106b ₁ , 106b ₂ is substantially the same, (b) substantially producing the lower electrode 110 at least partially on the acoustic mirror 106; (c) forming a piezoelectric layer 112 at least partially on the lower electrode 110; (d) generating an upper electrode 118 at least partially on the piezoelectric layer 112, The region in which the upper electrode 118, the piezoelectric layer 112, and the lower electrode 110 overlap each other defines an active region 122 of the piezoelectric resonator. Method of making piezoelectric resonators. The method of claim 24, Prior to generating the lower electrode 110, further comprising providing one or more layers 140 to separate or adjust other acoustic characteristics of the resonator on the acoustic mirror 106, The lower electrode 110 is formed on the one or more layers 140. Method of making piezoelectric resonators. The method of claim 24, (e) creating an intermediate layer on the structure from step (d); Repeating steps (b) to (c) to produce additional resonator structures on the intermediate layer. Method of making piezoelectric resonators.

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