Integration of back-end and acoustic processes for high-Q filters.

Abstract

Radio frequency RF filters (500-1, 500-2) are disclosed that vertically integrate an acoustic die (510, 514) with 2D or 3D inductors formed in one or more layers (520, 530, 540) on top of the acoustic die. The acoustic die is overmolded so that the acoustic dome, which is important for maintaining acoustic integrity, can be protected. The 2D inductors can be formed in the RDL layers (520, 540, 545, 555) on the overmold (515). The 3D inductors can be formed using through-mold vias (530) in a second mold (535) formed on top of the overmold (515). The fabrication of the through-mold vias can be by a mold-first method or a copper pillar-first method.

Description

[Technical field]

[0001] The present disclosure relates generally to radio frequency (RF) filters, and more particularly, but not exclusively, to high-Q RF filters and techniques for fabricating same. [Background technology]

[0002] Integrated circuit technology has achieved great strides in increasing computing power by miniaturizing active and passive components. Packaged devices can be found in many electronic devices including processors, servers, radio frequency (RF) integrated circuits, etc. Packaging technologies have become cost-effective for high pin count devices and / or high production volume parts.

[0003] Surface mounted device (SMD) inductors can be used in RF filters, however, they are not the most ideal due to their physical size, and SMD inductors can be expensive.

[0004] Therefore, there is a need for systems, devices, and methods that overcome the shortcomings of conventional RF filters, including the methods, systems, and devices provided herein. Summary of the Invention

[0005] The following presents a simplified summary of one or more aspects and / or examples related to the apparatus and methods disclosed herein. As such, the following summary should not be considered an extensive overview of all contemplated aspects and / or examples, nor should the following summary be considered to identify key or critical elements of all contemplated aspects and / or examples or to delineate the scope related to any particular aspect and / or example. As such, the following summary is intended only to present certain concepts related to one or more aspects and / or examples related to the apparatus and methods disclosed herein in a simplified form prior to the detailed description presented below. [Means for solving the problem]

[0006] An exemplary radio frequency (RF) filter is disclosed. The RF filter may comprise an acoustic die. The RF filter may also comprise a bottom mold formed on a side and a top surface of the acoustic die. The bottom mold may cover an acoustic dome of the acoustic die. The bottom mold may have one or more bottom mold via holes exposing one or more bond pads of the acoustic die. The RF filter may further comprise one or more bottom conductors formed on the bottom mold and in the one or more bottom mold via holes to electrically couple with the one or more bond pads. The RF filter may further comprise one or more inductors formed in one or more layers above the bottom mold. The one or more inductors may be electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that an electrical signal is filtered through the acoustic die and the one or more inductors.

[0007] A method of manufacturing an RF filter is disclosed. The method can include forming a bottom mold on a side and a top surface of an acoustic die. The bottom mold can cover an acoustic dome of the acoustic die. The bottom mold can have one or more bottom mold via holes exposing one or more bond pads of the acoustic die. The method can also include forming one or more bottom conductors on the bottom mold and in the one or more bottom mold via holes to electrically couple with the one or more bond pads. The method can further include forming one or more inductors in one or more layers above the bottom mold. The one or more inductors can be electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that an electrical signal is filtered through the acoustic die and the one or more inductors.

[0008] Other features and advantages associated with the apparatus and methods disclosed herein will become apparent to one with ordinary skill in the art upon review of the following drawings and detailed description.

[0009] A more complete appreciation of the same will be readily obtained as the aspects of the present disclosure and many of its attendant advantages become better understood by reference to the following detailed description, taken in conjunction with the accompanying drawings, which are presented merely to illustrate and not to limit the disclosure, and in which: [Brief description of the drawings]

[0010] [Figure 1] 1 is a graph of an example frequency response of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 2A] 1A and 1B are cross-sectional and top views of a conventional radio frequency filter including a surface mount device inductor. [Figure 2B] 1A and 1B are cross-sectional and top views of a conventional radio frequency filter including a surface mount device inductor. [Diagram 3] FIG. 2 illustrates a cross-sectional view of an example bulk acoustic wave die in accordance with one or more aspects of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view of incorporating a 3D solenoid inductor into a radio frequency filter with a bulk acoustic wave die using conventional manufacturing techniques. [Figure 5A] FIG. 1 illustrates an example of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 5B] FIG. 1 illustrates an example of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 5C] FIG. 1 illustrates an example of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 5D] FIG. 1 illustrates an example of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6A] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6B]1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6C] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6D] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6E] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6F] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 6G] 1A-1D illustrate example stages in the manufacture of a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 7A] 1A-1C illustrate examples of alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 7B] 1A-1C illustrate examples of alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 7C] 1A-1C illustrate examples of alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 7D] 1A-1C illustrate examples of alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 7E] 1A-1C illustrate examples of alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 8A] 11A-11C illustrate other alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 8B] 11A-11C illustrate other alternative stages for manufacturing a radio frequency filter in accordance with one or more aspects of the present disclosure. [Figure 9] 1 is a flowchart of an exemplary method for manufacturing an RF filter in accordance with one or more aspects of the present disclosure. [Figure 10]1 is a flowchart of an exemplary method for manufacturing an RF filter in accordance with one or more aspects of the present disclosure. [Figure 11] 1 is a flowchart of an exemplary method for manufacturing an RF filter in accordance with one or more aspects of the present disclosure. [Figure 12] 1 is a flowchart of an exemplary method for manufacturing an RF filter in accordance with one or more aspects of the present disclosure. [Figure 13] 1 is a flowchart of an exemplary method for manufacturing an RF filter in accordance with one or more aspects of the present disclosure. [Figure 14] FIG. 1 illustrates various electronic devices that may utilize one or more aspects of the present disclosure.

[0011] Other objects and advantages associated with the aspects disclosed herein will become apparent to those skilled in the art based on the accompanying drawings and detailed description. According to common practice, features illustrated by the drawings may not be drawn to scale. Thus, dimensions of illustrated features may be arbitrarily increased or decreased for clarity. According to common practice, some of the drawings have been simplified for clarity. Thus, the drawings may not show all components of a particular apparatus or method. Moreover, like reference numerals refer to like features throughout the specification and figures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Aspects of the present disclosure are illustrated in the following description and related drawings directed to specific embodiments. Alternative aspects or embodiments may be devised without departing from the scope of the teachings herein. In addition, well-known elements of the exemplary embodiments herein may not be described in detail or may be omitted so as not to obscure the relevant details of the teachings in the present disclosure.

[0013] In some described exemplary implementations, instances are identified where portions of the structure and operation of various components may be derived from known conventional techniques and configured in accordance with one or more exemplary embodiments. In such instances, some internal details of the structure and / or operation of known conventional components may be omitted to help avoid potentially obscuring the concepts illustrated in the exemplary embodiments disclosed herein.

[0014] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural unless the context clearly indicates otherwise. It is further to be understood that the terms "comprises", "comprising", "includes" and / or "including" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0015] FIG. 1 shows an example of a desired response of an RF filter, for example, for 5G New Radio (5G NR) applications. The bandpass frequency may be in the range of 2.1 GHz to 3.2 GHz. Typically, acoustic wave dies (e.g., surface acoustic wave (SAW) dies, bulk acoustic wave (BAW) dies, etc.) typically have a sharper roll-off response and better band selection (with narrower band) compared to LC type filters (e.g., LTCC, POG, etc.). If acoustic wave filters can be combined with other filters, it may be possible to achieve RF filters with good performance both near in-band and at harmonics, in terms of filter rejection, sensitivity, etc. Attempts to combine have been made by adding external filters (e.g., low pass filters (LPF), band pass filters (BPF), etc.) via stacked or discrete surface mount devices (SMD).

[0016] Unfortunately, such attempts to combine come with their own problems. For example, adding external filters via stacking or SMD consumes significant space, thus increasing module size and may also lead to performance degradation. SMD is subject to manufacturing and / or assembly variability. This may lead to coupling issues that may degrade RF performance. SMD inductors can also be expensive. Because SMD inductors are separate devices, keep-out zones may be necessary to provide sufficient component-to-chip isolation.

[0017] Another problem is that the SMD inductor is typically the tallest device on an RF filter module. This is illustrated in FIGS. 2A and 2B, which show a cross-sectional view and a top view of a conventional RF filter 200. As shown, the conventional RF filter 200 includes a BAW die 210 along with other circuitry. The RF filter 200 also includes a first SMD inductor 291 and a second SMD inductor 293. As shown, the SMD inductors 291, 293 are very tall relative to the remaining components of the RF filter 200. This means that there may be height limitations on the remaining modules and devices of the RF filter 200 due to the tall SMD inductors 291, 293.

[0018] 3 shows a cross-sectional view of a BAW die (e.g., BAW die 210). BAW die 300 may include a wafer 310 (e.g., a Si wafer), layers 320 including layers mirror and base, piezoelectric layer 350, bond pads 330, and bumps 340 on bond pads 330. To enable proper acoustic behavior, BAW die 300 also includes one or more acoustic dome structures 360, or simply acoustic domes 360. Acoustic domes 360 are on top of piezoelectric layer 350 and between bond pads 330.

[0019] One way to address the above issues may be to incorporate 3D solenoid inductors into RF filter devices instead of relying on SMD inductors. An example of how a 3D solenoid inductor is incorporated into an RF filter using conventional manufacturing techniques is shown in FIG. 4. In FIG. 4, an acoustic wafer structure 400 including multiple RF filters 400 may be placed on a reconstituted wafer 405.

[0020] As shown, multiple BAW dies 410 may be disposed on a reconstructed wafer 405. In this example, two BAW dies 410 are shown. Each BAW die 410 may be a BAW die 300 shown in FIG. 3. The BAW die 410 may include bond pads 412 (corresponding to bond pads 330). For simplicity, other components such as the wafer, layers, bumps, etc. are not shown. The dashed oval indicates the location of an acoustic dome for the BAW die 410. As shown, an acoustic dome 414 may be disposed between the bond pads 412.

[0021] A lower mold 415 may be formed on the reconstituted wafer 405 and on the BAW die 410 and back-ground to expose the bond pads 412. A lower polyimide layer 425 may be formed on the lower mold 415 and on the BAW die 410 and patterned to form via holes (lower polyimide via holes) at positions corresponding to the bond pads 412. That is, the bond pads 412 may be exposed through the lower polyimide via holes. Copper (Cu) may then be plated on the lower polyimide layer 425 and into the lower polyimide via holes to form bottom conductors 420 connected to the bond pads 412. The bottom conductors 420 may form a lower redistribution layer (RDL).

[0022] A Cu pillar 430 may be formed on the bottom conductor 420. Then, a top mold 435 may be deposited and back-ground to expose the top surface of the Cu pillar 430. A first top polyimide layer 445 may be formed on the top mold 435 and patterned to form a first top polyimide via hole at a location corresponding to the Cu pillar 430, exposing the top surface of the Cu pillar 430. Cu may then be plated on the first top polyimide layer 445 and into the first top polyimide via hole to form a top conductor 440 connected to the Cu pillar 430. The top conductor 440 may form the top RDL.

[0023] A second upper polyimide layer 455 may then be formed on the first upper polyimide layer 445 and processed to form a second upper polyimide via hole at a location that exposes the top surface of the top conductor 440. Cu may then be plated onto the second upper polyimide layer 455 and into the second upper polyimide via hole to form an external contact 450 connected to the top conductor 440. Solder 460 may then be formed on the external contact 450. In this manner, at least one solder 460 may be electrically coupled to at least one BAW die 410 via the external contact 450, the top conductor 440, the Cu pillar 430, the bottom conductor 420, and the bond pad 412.

[0024] Unfortunately, the RF filter device shown in FIG. 4 can be problematic. Recall that after the BAW die 410 is placed on the reconstructed wafer 405, a bottom mold 415 can be deposited on the reconstructed wafer 405 and on the BAW die 410 to cover the top of the BAW die 410. The bottom mold 415 can then be back-ground to expose the bond pads 412. However, as seen in FIG. 3, the acoustic dome 360 ​​provided for proper acoustic behavior is above the bond pads 330. This means that the acoustic dome 360 ​​of the BAW die 410 can be damaged when the bottom mold 415 is back-ground to expose the bond pads 412.

[0025] One or more techniques are proposed to address such issues. That is, it is proposed to provide an RF filter by a technique incorporating a 3D (or solenoid) inductor without damaging the acoustic dome of the acoustic die (e.g., BAW die). FIG. 5A shows an example of an RF filter 500-1 that may comprise an acoustic die 510. In one embodiment, the acoustic die 510 may be a BAW die, such as the BAW die 300. For purposes of explanation, it is assumed that the acoustic die 510 is a BAW die, but it is recognized that other types of acoustic dies may be used instead.

[0026] An under mold 515, which may be insulating, may be formed on the sides and top surface of the BAW die 510. That is, the BAW die 510 may be overmolded with the under mold 515. The under mold 515 may be patterned with one or more under mold via holes in a location such that at least a portion of the top surface of the bond pads 512 is exposed through the one or more under mold via holes. The dashed oval 514 may represent an acoustic dome of the BAW die 510.

[0027] By overmolding, the bottom mold 515 may be formed over the BAW die 510 such that the bottom mold 515 covers the acoustic dome 514 of the BAW die. Note that the top surface of the bottom mold 515 is well above the acoustic dome 514 of the BAW die 510. The bottom mold 515 can be said to encapsulate the acoustic dome 514. As a result, the acoustic dome 514 can be protected, which can maintain the acoustic integrity of the BAW die 510 and potentially improve the performance of the RF filter 500-1 overall.

[0028] A conductive material (e.g., Cu, Al, etc.) may be deposited and patterned on the bottom mold 515 and into the bottom mold vias to form one or more bottom conductors 520. The bottom conductors 520 may be electrically coupled to the bond pads 512. For example, the portions of the bottom conductors 520 formed in the bottom mold vias may be in physical or ohmic contact with the bond pads 512. The bottom conductors 520 may form a lower redistribution layer (RDL) of the RF filter 510-1.

[0029] Then, a conductive material (e.g., Cu) may be deposited and patterned to form one or more conductive pillars 530 on the bottom conductor 520 and on the bottom mold 515. In one embodiment, the height of the conductive pillar 530 may be in the range of 150 to 200 microns. The dimensions (height, thickness) of the conductive pillar 530 may be determined based on the desired characteristics (e.g., the desired dielectric value). The conductive pillar 530 may be electrically coupled to the bottom conductor 520. For example, the conductive pillar 530 may be in physical or ohmic contact with the bottom conductor 520. In this case, it can be said that the conductive pillar 530 may be electrically coupled to the lower RDL.

[0030] A top mold 535, which may be insulating, may be deposited and patterned to encapsulate the sides of the conductive pillars 530 while leaving the tops of the conductive pillars 530 exposed.

[0031] A first passivation layer 545 may be deposited and patterned on the top mold 535 to form one or more first top passivation vias to expose at least a portion of the one or more conductive pillars 530. The first passivation layer 545 may be a first polyimide layer.

[0032] A conductive material (e.g., Cu) may be deposited and patterned on the first passivation layer 545 and in the first upper passivation via to form a top conductor 540. The top conductor 540 may be electrically coupled to the conductive pillar 530. For example, the portion of the top conductor 540 formed in the first upper passivation via may be in physical or ohmic contact with the conductive pillar 530. The top conductor 540 may form a top RDL of the RF filter 510-1. In this case, it may be said that the conductive pillar 530 may also be electrically coupled to the top RDL.

[0033] A second passivation layer 555 may be deposited and patterned on the first passivation layer 545 to form one or more second upper passivation vias to expose at least a portion of the one or more upper conductors 540. The second passivation layer 555 may be a second polyimide layer.

[0034] A conductive material (e.g., Cu) may be deposited and patterned on the second passivation layer 555 and in the second upper passivation vias to form one or more external contacts 550. The external contacts 550 may be electrically coupled to the upper conductors 540. For example, the portions of the external contacts 550 formed in the second upper passivation vias may be in physical or ohmic contact with the upper conductors 540. The external contacts 550 may enable the RF filter 500-1 to be connected to devices external to the RF filter 500-1. Also, note that the external contacts 550 do not have to be vertically aligned with the bond pads 512 due to the lower and / or upper RDLs. More specifically, the centers of the external contacts 550 do not have to coincide with the centers of the bond pads 512. This means that there may be a great deal of flexibility in routing signals.

[0035] An interconnect 560 may be formed on the external contact 550. In one embodiment, the interconnect 560 may be formed using solder. As a result, at least one interconnect 560 may be electrically coupled to the BAW die 510 via at least one external contact 550, at least one top conductor 540, at least one conductive pillar 530, at least one bottom conductor 520, and at least one bond pad 512. It may also be said that at least one interconnect 560 is electrically coupled to the BAW die 510 via at least one external contact 550, the top RDL, the at least one conductive pillar 530, the bottom RDL, and at least one bond pad 512.

[0036] FIG. 5B illustrates an example of a 3D inductor 580 (or solenoid inductor 580) that may be formed in the RF filter 500-1. In one embodiment, the 3D inductor 580 may be formed through a combination of one or more conductive pillars 530, one or more bottom conductors 520, and one or more top conductors 540. In particular, one or more loops of the 3D inductor 580 may comprise one or more conductive pillars 530, one or more bottom conductors 520, and one or more top conductors 540. That is, the loops of the 3D inductor 580 may be formed through the bottom RDL (i.e., bottom conductor 520), the top RDL (i.e., top conductor 540), and the conductive pillar 530. Although not shown, there may be any number of 3D inductors 580 formed by the conductive pillars 530, the bottom conductors 520, and the top conductors 540.

[0037] It should be noted that the at least one 3D inductor 580 may be electrically coupled to the BAW die 510. As a result, electrical signals may be filtered through both the BAW die 510 and the at least one 3D inductor 580. Also, the at least one external contact 550 may be electrically coupled to the acoustic die through one or more inductors, such as the at least one 3D inductor 580.

[0038] There may be cases where a very high Q filter is not required. In these instances, a 2D inductor (or stacked inductor) may be sufficient. Figure 5C shows an example of an RF filter 500-2, which may also include an acoustic die 510 (e.g., a BAW die). RF filter 500-2 of Figure 5C may be similar to RF filter 500-1 (of Figure 5A), except that a 2D inductor may be formed instead of a 3D inductor.

[0039] RF filter 500-2 may include a BAW die molded with an under mold 515. Similar to FIG. 5A, BAW die 510 may be overmolded. As a result, acoustic dome 514 of BAW die 510 may be protected by under mold 515. Under mold 515 may be patterned with one or more under mold via holes in locations such that at least a portion of the top surface of bond pad 512 is exposed through the one or more under mold via holes.

[0040] A conductive material (e.g., Cu, Al, etc.) may be deposited and patterned on the bottom mold 515 and into the bottom mold vias to form bottom conductors 520. The bottom conductors 520 may be electrically coupled to the bond pads 512 (e.g., a portion of the bottom conductors 520 may be in physical or ohmic contact with the bond pads 512). The bottom conductors 520 may form a lower RDL of the RF filter 510-2.

[0041] Note that the conductive pillars 530 and the top mold 535 are absent. Instead, a first passivation layer 545 may be deposited and patterned on the bottom mold 515 to form one or more first top passivation vias to expose at least a portion of the one or more bottom conductors 520. The first passivation layer 545 may be a first polyimide layer.

[0042] A conductive material (e.g., Cu) may be deposited and patterned on the first passivation layer 545 and into the first upper passivation via to form a top conductor 540. The top conductor 540 may be electrically coupled to the bottom conductor 520 (e.g., a portion of the top conductor 540 may be in physical or ohmic contact with the bottom conductor 520). The top conductor 540 may form a top RDL of the RF filter 510-2. In this case, it may be said that the top and bottom RDLs may be electrically coupled.

[0043] A second passivation layer 555 may be deposited and patterned on the first passivation layer 545 to form one or more second upper passivation vias to expose at least a portion of the one or more upper conductors 540. The second passivation layer 555 may be a second polyimide layer.

[0044] A conductive material (e.g., Cu) may be deposited and patterned on the second passivation layer 555 and into the second upper passivation vias to form one or more external contacts 550. The external contacts 550 may be electrically coupled to the upper conductors 540 (e.g., a portion of the external contacts 550 may be in physical or ohmic contact with the upper conductors 540).

[0045] Interconnects 560 (e.g., solder) may be formed on the external contacts 550. As a result, at least one interconnect 560 may be electrically coupled to the BAW die 510 via the at least one external contact 550, the at least one top conductor 540, the at least one bottom conductor 520, and the at least one bond pad 512.

[0046] FIG. 5D shows an example of a 2D inductor 585 (or stacked inductor 585) that may be formed in the RF filter 500-2. In one embodiment, the 2D inductor 585 may be formed through one or more bottom conductors 520. That is, the loop of the 2D inductor may be formed by one or more bottom conductors 520, i.e., by the bottom RDL. Alternatively or in addition, the 2D inductor 585 may be formed through one or more top conductors 540. That is, the loop of the 2D inductor may be formed by one or more top conductors 540, i.e., by the top RDL. Although not shown, there may be any number of 3D inductors 580 formed by the bottom conductors 520 and / or the top conductors 540. When there are multiple 2D inductors, some may be formed through the bottom conductors 520 and others may be formed through the top conductors 540.

[0047] It should be noted that the at least one 2D inductor 585 may be electrically coupled to the BAW die 510. As a result, electrical signals may be filtered through both the BAW die 510 and the at least one 2D inductor 585. Also, the at least one external contact 550 may be electrically coupled to the acoustic die through one or more inductors, such as the at least one 2D inductor 585.

[0048] 5A and 5C, it should be noted that RF filters 500-1, 500-2 (collectively RF filters 500) are examples of vertical integration, i.e., acoustic die 510 and passive filters may be vertically integrated, which may help save space.

[0049] 6A-6G illustrate example stages of fabricating an RF filter, such as RF filter 500-1 (of FIGS. 5A and 5B), according to one or more aspects of the present disclosure. In general, an acoustic die may be fabricated first. An integrated passive device (IPD) formation process may then be performed to integrate one or more passive elements (e.g., inductors) with the acoustic die. Again, for purposes of illustration, a BAW die is used as an example of the acoustic die.

[0050] 6A illustrates a stage where one or more BAW dies 510 may be placed on a reconstituted wafer 605. The reconstituted wafer 605 may also be referred to as a bonding / debonding wafer 605.

[0051] 6B shows a stage where a bottom mold 515 may be deposited on the reconstituted wafer 605 and on the BAW die 510 to cover the BAW die 510. The bottom mold 515 may be patterned to form bottom mold via holes 617 at locations corresponding to the bond pads 512 of the BAW die 510. The bond pads 512 may be exposed by the bottom mold via holes 617.

[0052] In one embodiment, the bottom mold via holes 617 may be formed by laser drilling the bottom mold 515. For example, the BAW die 510 may be overmolded such that the top surface of the BAW die 510. In particular, the top of the BAW die 510 between the bond pads 512, i.e., the portion corresponding to the acoustic dome 514, is covered with the bottom mold 515. The portion of the bottom mold 515 corresponding to the bond pads 512 may then be laser drilled to form the bottom mold via holes 617.

[0053] Note that after overmolding the BAW die 510, the bottom mold 515 can be planarized prior to laser drilling. However, the planarization is not used to expose the bond pads 512. Rather, bottom mold via holes 617 are formed to expose the bond pads 512. In this manner, the acoustic dome 514 remains protected by the bottom mold 515.

[0054] 6C illustrates a stage where one or more conductive materials (e.g., metals such as Cu, Al, etc.) may be deposited on the bottom mold 515 and into the bottom mold via holes 617 to form one or more bottom conductors 520. The bottom RDL may comprise one or more bottom conductors 520.

[0055] FIG. 6D shows a stage where one or more conductive materials (e.g., Cu, Al, etc.) can be deposited and patterned on the bottom conductor 520 to form one or more conductive pillars 530.

[0056] 6E illustrates a stage where a top mold 535 may be deposited and patterned over the bottom mold 515 and the bottom RDL (e.g., bottom conductors 520). The top mold 535 may be formed on the sides of the conductive pillars 530 and patterned to expose the top surfaces of the conductive pillars 530. For example, the top mold 535 may be deposited to encapsulate the conductive pillars 530, including their top surfaces. The top mold 535 may then be planarized (e.g., back-ground) to expose the conductive pillars 530.

[0057] 6F shows a stage where a first passivation layer 545 may be deposited on the upper mold 535 and on the conductive pillars 530. The first passivation layer 545 may be patterned to form a first upper passivation via hole to expose at least a portion of the one or more conductive pillars 530. One or more conductive materials (e.g., Cu, Al, etc.) may then be deposited and patterned on the first passivation layer 545 and in the first upper passivation via hole to form one or more upper conductors 540. The upper RDL may comprise one or more upper conductors 540.

[0058] As noted above with respect to FIG. 5B, one or more 3D inductors 580 may be formed in the steps illustrated in FIGS. 6C-6F.

[0059] 6G illustrates a stage where one or more conductive materials (e.g., Cu, Al, etc.) may be deposited and patterned on the top RDL (e.g., on the top conductor 540) to form one or more external contacts 550. One or more interconnects (e.g., solder) 560 may also be formed on the external contacts 550. Although not shown, individual RF filters 500-1 may be sliced ​​from the other RF filters 500-1 after the reconstituted wafer 605 is peeled off.

[0060] 6B and 6C, it is shown that the bottom mold via hole 617 can be laser drilled and the bottom conductor 520 can be formed to fill the bottom mold via hole 617. There are other ways to form the bottom conductor 520.

[0061] Figures 7A-7E show exemplary stages of one such alternative technique. The manufacturing process can proceed from Figure 6A to Figure 7A, which shows a stage where photoresist 715 can be deposited on reconstructed wafer 605 and on BAW die 510 to cover BAW die 510. The photoresist can be patterned (e.g., by masking and exposure) to form photoresist via holes 717 at locations corresponding to bond pads 512 such that bond pads 512 are exposed.

[0062] 7B illustrates a stage where one or more conductive materials (e.g., metals such as Cu, Al, etc.) may be deposited in the photoresist via holes 717 to form bottom conductor pillars 522. For example, a plating process may be utilized to form the bottom conductor pillars 522.

[0063] FIG. 7C shows a stage where the photoresist 715 may be removed.

[0064] 7D shows a stage where the bottom mold 515 may be deposited on the reconstructed wafer 605 and on the BAW die 510 such that the top surface of the bottom mold 515 is at the same level as the bottom conductor pillars 522. For example, the bottom mold 515 may be deposited to cover the bottom conductor pillars 522 and then planarized to expose the top surface of the bottom conductor pillars 522. The acoustic dome 514 of the BAW die 510 is still protected because the portion corresponding to the acoustic dome 514 is covered by the bottom mold 515 and is not subject to planarization.

[0065] 7E shows a stage where one or more conductive materials (e.g., metals such as Cu, Al, etc.) may be deposited to form one or more bottom conductors 520. The manufacturing process then proceeds to the stage shown in FIG. 6D. In this embodiment, one or more 3D inductors 580 may be formed at the stages shown in FIG. 7E-FIG. 6F.

[0066] Figures 8A and 8B show stages in fabricating the alternative RF filter 500-2 shown in Figures 5C and 5D. The fabrication process can proceed from Figure 6C to Figure 8A, which shows a stage where a first passivation layer 545 can be deposited on the lower mold 515 and on the lower conductors 520. Alternatively, the fabrication process can proceed from the stage of Figure 7E to the stage of Figure 8A.

[0067] 8A, the first passivation layer 545 may be patterned to form a first upper passivation via hole to expose at least a portion of the one or more bottom conductors 520. One or more conductive materials (e.g., Cu, Al, etc.) may then be deposited and patterned on the first passivation layer 545 and in the first upper passivation via hole to form one or more top conductors 540. In this case, it may be said that the upper RDL (including the upper conductors 540) may be formed on the lower RDL (including the bottom conductors 520).

[0068] As noted above with respect to Figure 5D, one or more 2D inductors 585 may be formed in the stages shown in Figures 6C and 8 A. Alternatively, one or more 2D inductors 585 may be formed in the stages shown in Figures 7E and 8 A.

[0069] 8B illustrates a stage where one or more conductive materials (e.g., Cu, Al, etc.) may be deposited and patterned on the top RDL (e.g., on the top conductor 540) to form one or more external contacts 550. Also, one or more interconnects (e.g., solder) 560 may be formed on the external contacts 550.

[0070] 9 shows a flowchart of an example method 900 of fabricating an RF filter, such as RF filters 500-1, 500-2. In block 910, a bottom mold 515 may be formed on the sides and top of an acoustic die 510. The bottom mold 515 may cover an acoustic dome 514 of the acoustic die 510 (e.g., a BAW die). The bottom mold 515 may have one or more bottom mold via holes 617 that expose one or more bond pads 512 of the acoustic die 510.

[0071] In block 920, one or more bottom conductors 520 may be formed on the bottom mold 515 and in the one or more bottom mold via holes 617 to electrically couple to the one or more bond pads (512).

[0072] 10 illustrates a flow chart of an exemplary process for implementing blocks 910 and 920. In block 1010, acoustic die 510 may be placed on reconstructed wafer 605.

[0073] In block 1020, a bottom mold 515 may be formed over the reconstructed wafer 605 and the acoustic die 510. The bottom mold 515 may cover the acoustic die 510.

[0074] At block 1030, one or more bottom mold via holes 617 may be formed in the bottom mold 515 to expose one or more bond pads 512. In one embodiment, the bottom mold 515 may be laser drilled to form the one or more bottom mold via holes 617.

[0075] At block 1040, one or more conductive materials (e.g., Cu, Al, etc.) may be deposited and patterned on the bottom mold 515 and in the one or more bottom mold via holes 617 to form one or more bottom conductors 520. The acoustic dome 514 may remain covered by the bottom mold 515 after forming the one or more bottom conductors 520.

[0076] 11 shows a flow chart of another exemplary process for implementing blocks 910 and 920. In block 1110, acoustic die 510 may be placed on reconstructed wafer 605.

[0077] In block 1120, photoresist 715 may be deposited and patterned on the reconstructed wafer 605 and the acoustic die 510 to form one or more photoresist via holes 717 to expose one or more bond pads 512. The photoresist 715 may cover the acoustic dome 514 of the acoustic die 510.

[0078] In block 1130, one or more first conductive materials (e.g., Cu, Al, etc.) may be deposited and patterned into one or more photoresist via holes 717 to form one or more bottom conductor pillars 522.

[0079] In block 1140, the photoresist 715 may be removed.

[0080] In block 1150, a lower mold 515 may be formed over the reconstructed wafer 605 and the acoustic die 510 such that a top surface of the lower mold 515 and a top surface of the one or more lower conductor pillars 522 are flat. The lower mold 515 may cover the acoustic dome 514 of the acoustic die 510.

[0081] In block 1160, one or more second conductive materials (e.g., Cu, Al, etc.) may be deposited and patterned on the lower mold 515 and on the one or more lower conductor pillars 522 to form one or more lower conductors 520.

[0082] 9, in block 930, one or more inductors 580, 585 may be formed in one or more layers above the bottom mold 515. The one or more inductors 580, 585 may be electrically coupled to the acoustic die 510 via one or more bottom conductors 520 and one or more bond pads 512 such that electrical signals are filtered through the acoustic die 510 and the one or more inductors 580, 585.

[0083] In one aspect, the one or more inductors may include at least one 3D (or solenoid) inductor 580. Figure 12 shows a flowchart of an example process for performing block 930 to form the 3D inductor 580. In block 1210, one or more conductive pillars 530 may be formed on the one or more bottom conductors 520.

[0084] In block 1220, an upper mold 535 may be formed over the lower mold 515 and the one or more bottom conductors 520. The upper mold 535 may encapsulate sides of the one or more conductive pillars 530.

[0085] In block 1230, a first passivation layer 545 may be formed on the top mold 535. The first passivation layer 545 may have one or more first passivation via holes that expose the top surfaces of the one or more conductive pillars.

[0086] In block 1240, one or more first conductive materials (e.g., copper, aluminum, etc.) may be deposited and patterned on the first passivation layer 545 and into the one or more first passivation via holes to form one or more top conductors 540. The one or more top conductors 540 may be electrically coupled to the one or more conductive pillars 530. At least one 3D inductor 580 may comprise one or more loops formed by the one or more conductive pillars 530, the one or more bottom conductors 520 (i.e., bottom RDL), and the one or more top conductors 540 (i.e., top RDL).

[0087] In block 1250, a second passivation layer 555 may be formed on the first passivation layer 545. The second passivation layer 555 may have one or more second passivation via holes that expose a top surface of the one or more top conductors 540.

[0088] At block 1260, one or more second conductive materials (e.g., copper, aluminum, etc.) may be deposited and patterned on the second passivation layer 555 and into the one or more second passivation via holes to form one or more external contacts 550. In this case, the one or more external contacts 550 may be electrically coupled to the acoustic die 510 through at least one 3D inductor 580.

[0089] In another aspect, the one or more inductors may include at least one 2D (or stacked) inductor 585. Figure 13 shows a flow chart of an example process for performing block 930 to form the 2D inductor 585. In block 1310, a first passivation layer 545 may be formed on the lower mold 515 and on the one or more bottom conductors 520. The first passivation layer 545 may have one or more first passivation via holes that expose the top surfaces of the one or more bottom conductors 520.

[0090] In block 1320, one or more first conductive materials (e.g., copper, aluminum, etc.) may be deposited and patterned on the first passivation layer 545 and into the one or more first passivation via holes to form one or more top conductors 540. The one or more top conductors 540 may be electrically coupled to the one or more bottom conductors 520. At least one 2D inductor 585 may comprise one or more loops formed by the one or more bottom conductors 520 (e.g., by a bottom RDL) or by the one or more top conductors 540 (e.g., by a top RDL).

[0091] In block 1330, a second passivation layer 555 may be formed on the first passivation layer 545. The second passivation layer 555 may have one or more second passivation via holes that expose a top surface of the one or more top conductors 540.

[0092] At block 1340, one or more second conductive materials (e.g., copper, aluminum, etc.) may be deposited and patterned on the second passivation layer 555 and into the one or more second passivation via holes to form one or more external contacts 550. In this case, the one or more external contacts 550 may be electrically coupled to the acoustic die 510 through at least one 2D inductor 585.

[0093] It will be understood that the foregoing fabrication process and related description are provided merely as general illustrations of some of the aspects of the present disclosure, and are not intended to limit the scope of the present disclosure or the appended claims. Furthermore, many details in the fabrication process known to those skilled in the art may be omitted or combined in a summary process section to facilitate understanding of the various aspects disclosed without detailed description of each detail and / or all possible process variations. Furthermore, it will be understood that the illustrated configurations and descriptions are provided merely to aid in the explanation of the various aspects disclosed herein. For example, the number and location of inductors, the metallization structure may have more or fewer conductive and insulating layers, the orientation, size, and other aspects of the cavities, whether formed of multiple cavities, closed or open, and other aspects may have variations brought about by specific application design features, such as the number of antennas, antenna type, frequency range, power, etc. Thus, the foregoing illustrative examples and related figures should not be construed as limiting the various aspects disclosed and claimed herein.

[0094] 14 illustrates various electronic devices that may be integrated with any of the aforementioned devices according to various aspects of the present disclosure. For example, a mobile phone device 1402, a laptop computer device 1404, and a fixed location terminal device 1406 may each be generally considered user equipment (UE) and may include an RF filter 1400 (e.g., RF filters 500-1, 500-2) as described herein. The devices 1402, 1404, 1406 illustrated in FIG. 14 are merely examples. Other electronic devices may also include RF filters including groups of devices (e.g., electronic devices) including, but not limited to, mobile devices, handheld personal communications system (PCS) units, portable data units such as personal digital assistants, global positioning system (GPS) enabled devices, navigation devices, set-top boxes, music players, video players, entertainment units, stationary data units such as meter reading equipment, communications devices, smartphones, tablet computers, computers, wearable devices, servers, routers, electronic devices implemented within automotive vehicles (e.g., autonomous vehicles), Internet of Things (IoT) devices, or any other device that stores or retrieves data or computer instructions, or any combination thereof.

[0095] The devices and functions disclosed above may be designed and configured into computer files (e.g., RTL, GDSII, GERBER, etc.) stored on a computer readable medium. Some or all of such files may be provided to a fabricator who fabricates devices based on such files. The resulting product may include semiconductor wafers that are then cut into semiconductor dies and packaged with antennas on glass devices. The antennas on glass devices may then be used in devices described herein.

[0096] The following numbered clauses describe example implementations.

[0097] Clause 1: A radio frequency (RF) filter comprising: an acoustic die; a bottom mold having one or more bottom mold via holes formed on a side and a top surface of the acoustic die, covering an acoustic dome of the acoustic die and exposing one or more bond pads of the acoustic die; one or more bottom conductors formed on the bottom mold and in the one or more bottom mold via holes to electrically couple to the one or more bond pads; and one or more inductors formed in one or more layers above the bottom mold, the one or more inductors being electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that an electrical signal is filtered through the acoustic die and the one or more inductors.

[0098] Clause 2: The RF filter of clause 1, wherein the one or more inductors include at least one 3D inductor.

[0099] Clause 3: The RF filter of clause 2, further comprising one or more conductive pillars formed on the one or more bottom conductors and one or more top conductors formed on the one or more conductive pillars, wherein the at least one 3D inductor comprises one or more loops formed by the one or more conductive pillars, the one or more bottom conductors, and the one or more top conductors.

[0100] Clause 4: The RF filter of clause 3, further comprising: an upper mold formed on the lower mold and the one or more lower conductors and encapsulating sides of the one or more conductive pillars; and a first passivation layer formed on the upper mold, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more conductive pillars, the one or more upper conductors being formed on the first passivation layer and in the one or more first passivation via holes so as to be electrically coupled to the one or more conductive pillars.

[0101] Clause 5: An RF filter as described in any of clauses 4, further comprising: a second passivation layer formed on the first passivation layer and having one or more second passivation via holes exposing a top surface of the one or more upper conductors; and one or more external contacts formed on the second passivation layer and in the one or more second passivation via holes for electrically coupling to the acoustic die via at least one 3D inductor.

[0102] Clause 6: The RF filter of clause 5, wherein the first passivation layer is a first polyimide layer, the second passivation layer is a second polyimide layer, the one or more external contacts are formed from copper, or any combination thereof.

[0103] Clause 7: The RF filter of clause 1, wherein the one or more inductors include at least one 2D inductor.

[0104] Clause 8: An RF filter as described in Clause 7, further comprising one or more upper conductors formed on the one or more lower conductors, and wherein at least one 2D inductor comprises one or more loops formed by the one or more lower conductors or by the one or more upper conductors.

[0105] Clause 9: The RF filter of clause 8, further comprising a first passivation layer formed on the lower mold, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more lower conductors, the one or more upper conductors being formed on the first passivation layer and in the one or more first passivation via holes so as to be electrically coupled to the one or more lower conductors.

[0106] Clause 10: The RF filter of clause 9, further comprising: a second passivation layer formed on the first passivation layer and having one or more second passivation via holes exposing top surfaces of the one or more upper conductors; and one or more external contacts formed on the second passivation layer and in the one or more second passivation via holes for electrically coupling to the acoustic die via at least one 2D inductor.

[0107] Clause 11: The RF filter of clause 10, wherein the first passivation layer is a first polyimide layer, the second passivation layer is a second polyimide layer, the one or more external contacts are formed from copper, or any combination thereof.

[0108] Clause 12: The RF filter of any of clauses 1-11, wherein the acoustic die is a bulk acoustic wave (BAW) die.

[0109] Clause 13: An RF filter according to any one of clauses 1 to 12, wherein one or more bottom conductors are formed from copper, one or more inductors are formed from copper, or both.

[0110] Clause 14: An RF filter according to any of clauses 1 to 13, wherein the RF filter is incorporated into an apparatus selected from the group consisting of a music player, a video player, an entertainment unit, a navigation device, a communications device, a mobile device, a mobile phone, a smartphone, a personal digital assistant, a fixed location terminal, a tablet computer, a computer, a wearable device, an Internet of Things (IoT) device, a laptop computer, a server, and a device in an automotive vehicle.

[0111] Clause 15: A method for manufacturing a radio frequency (RF) filter, comprising: forming a bottom mold on a side and a top surface of an acoustic die, the bottom mold covering an acoustic dome of the acoustic die and having one or more bottom mold via holes exposing one or more bond pads of the acoustic die; forming one or more bottom conductors on the bottom mold and in the one or more bottom mold via holes to electrically couple to the one or more bond pads; and forming one or more inductors in one or more layers above the bottom mold, the one or more inductors being electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that an electrical signal is filtered through the acoustic die and the one or more inductors.

[0112] Clause 16: The method of clause 15, wherein forming a lower mold and forming one or more lower conductors includes placing an acoustic die on a reconstructed wafer; forming a lower mold over the reconstructed wafer and the acoustic die, the lower mold covering the acoustic die; forming one or more lower mold via holes in the lower mold to expose one or more bond pads; and depositing and patterning one or more conductive materials on the lower mold and in the one or more lower mold via holes to form the one or more lower conductors, wherein the acoustic dome remains covered by the lower mold after forming the one or more upper conductors.

[0113] Clause 17: The method of clause 16, wherein the one or more lower mold via holes are formed by laser drilling the lower mold.

[0114] Clause 18: The method of any of clauses 16-17, wherein the one or more conductive materials include copper.

[0115] Clause 19: The method of any of clauses 15-18, wherein forming the bottom mold and forming the one or more bottom conductors includes: placing the acoustic die on a reconstructed wafer; depositing and patterning a photoresist, the photoresist covering an acoustic dome of the acoustic die, on the reconstructed wafer and the acoustic die to form one or more photoresist via holes to expose the one or more bond pads; depositing and patterning one or more first conductive materials in the one or more photoresist via holes to form one or more bottom conductor pillars; removing the photoresist; forming a bottom mold, the bottom mold covering the acoustic dome of the acoustic die, on the reconstructed wafer and the acoustic die such that a top surface of the bottom mold and top surfaces of the one or more bottom conductor pillars are planar; and depositing and patterning one or more second conductive materials on the bottom mold and on the one or more bottom conductor pillars to form the one or more bottom conductors.

[0116] Clause 20. The method of clause 19, wherein the one or more bottom conductors including the bottom conductor pillars are formed from copper.

[0117] Clause 21: The method of any of clauses 15 to 20, wherein the one or more inductors include at least one 3D inductor.

[0118] Clause 22: The method of clause 21, wherein forming the one or more inductors includes forming one or more conductive pillars on the one or more bottom conductors; forming an upper mold on the lower mold and the one or more bottom conductors, the upper mold encapsulating sides of the one or more conductive pillars; forming a first passivation layer on the upper mold, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more conductive pillars; and depositing and patterning one or more first conductive materials on the first passivation layer and in the one or more first passivation via holes to form one or more upper conductors, the one or more upper conductors electrically coupled to the one or more conductive pillars, wherein at least one 3D inductor comprises one or more loops formed by the one or more conductive pillars, the one or more bottom conductors, and the one or more upper conductors.

[0119] Clause 23: The method of clause 22, wherein forming the one or more inductors further includes forming a second passivation layer on the first passivation layer, the second passivation layer having one or more second passivation via holes exposing a top surface of the one or more upper conductors, and depositing and patterning one or more second conductive materials on the second passivation layer and in the one or more second passivation via holes to form one or more external contacts, the one or more external contacts being electrically coupled to the acoustic die via the at least one 3D inductor.

[0120] Clause 24: The method of clause 23, wherein one or more conductive pillars are formed from copper, one or more top conductors are formed from copper, one or more external contacts are formed from copper, or any combination thereof.

[0121] Clause 25: The method of any of clauses 15 to 20, wherein the one or more inductors include at least one 2D inductor.

[0122] Clause 26: The method of clause 25, wherein forming the one or more inductors includes forming a first passivation layer on the lower mold and on the one or more lower conductors, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more lower conductors, and depositing and patterning one or more first conductive materials on the first passivation layer and in the one or more first passivation via holes to form one or more upper conductors, the one or more upper conductors being electrically coupled to the one or more lower conductors, wherein at least one 2D inductor comprises one or more loops formed by the one or more lower conductors or by the one or more upper conductors.

[0123] Clause 27: The method of clause 26, wherein forming the one or more inductors further includes forming a second passivation layer on the first passivation layer, the second passivation layer having one or more second passivation via holes exposing a top surface of the one or more upper conductors, and depositing and patterning one or more second conductive materials on the second passivation layer and in the one or more second passivation via holes to form one or more external contacts, the one or more external contacts being electrically coupled to the acoustic die via the at least one 2D inductor.

[0124] Clause 28: The method of clause 27, wherein one or more top conductors are formed from copper, one or more external contacts are formed from copper, or both.

[0125] Clause 29: The method of any of clauses 15 to 28, wherein the acoustic die is a bulk acoustic wave (BAW) die.

[0126] Clause 30: The method of any of clauses 15-29, wherein the one or more bottom conductors are formed from copper, the one or more inductors are formed from copper, or both.

[0127] As used herein, terms such as "user equipment" (or "UE"), "user device", "user terminal", "client device", "communication device", "wireless device", "wireless communication device", "handheld device", "mobile device", "mobile terminal", "mobile station", "handset", "access terminal", "subscriber device", "subscriber terminal", "subscriber station", "terminal", and variations thereof may interchangeably refer to any suitable mobile or fixed device capable of receiving wireless communication and / or navigation signals. These terms include, but are not limited to, music players, video players, entertainment units, navigation devices, communication devices, smartphones, personal digital assistants, fixed location terminals, tablet computers, computers, wearable devices, laptop computers, servers, automotive devices in automotive vehicles, and / or other types of portable electronic devices that are typically carried by a person and / or have communication capabilities (e.g., wireless, cellular, infrared, short range radio, etc.). These terms are also intended to include a device that communicates with another device capable of receiving wireless communication and / or navigation signals, such as by a short-range wireless connection, an infrared connection, a wired connection, or other connection, regardless of whether the satellite signal reception, assistance data reception, and / or location-related processing occurs on that device or on another device. Furthermore, these terms are intended to include all devices, including wireless and wired communication devices, that can communicate with a core network via a Radio Access Network (RAN) through which the UE can connect to external networks, such as the Internet, and to other UEs. Of course, other mechanisms for connecting to a core network and / or the Internet are also possible for a UE, such as via a wired access network, a Wireless Local Area Network (WLAN) (e.g., based on IEEE 802.11, etc.), etc.A UE may be embodied by any of several types of devices, including, but not limited to, a printed circuit (PC) card, a compact flash device, an external or internal modem, a wireless or wired phone, a smart phone, a tablet, a tracking device, an asset tag, etc. A communication link through which a UE can transmit signals to a RAN is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which a RAN can send signals to a UE is called a downlink channel or a forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term traffic channel (TCH) can refer to either an uplink / reverse traffic channel or a downlink / forward traffic channel.

[0128] Wireless communication between electronic devices can be based on various technologies, such as Code Division Multiple Access (CDMA), W-CDMA, Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), Global System for Mobile Communications (GSM), 3GPP® Long Term Evolution (LTE), 5G New Radio, Bluetooth (BT), Bluetooth Low Energy (BLE), IEEE 802.11 (WiFi), and IEEE 802.15.4 (Zigbee / Thread) or other protocols that may be used within wireless or data communication networks. Bluetooth Low Energy (also known as Bluetooth LE, BLE, and Bluetooth Smart) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group that aims to significantly reduce power consumption and cost while maintaining a similar communication range. BLE was integrated into the main Bluetooth standard in 2010 by adopting the Bluetooth Core Specification Version 4.0 and was updated in Bluetooth 5.

[0129] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any detail described herein as "exemplary" should not be construed as advantageous over other examples. Likewise, the term "example" does not imply that all examples include the described features, advantages or modes of operation. Furthermore, particular features and / or structures may be combined with one or more other features and / or structures. Moreover, at least a portion of the apparatus described herein may be configured to perform at least a portion of the methods described herein.

[0130] It should be noted that the terms "connected" and "coupled," or any variation thereof, mean any direct or indirect connection or coupling between elements, unless the connection is expressly disclosed as being directly connected, and may encompass the presence of intermediate elements between two elements that are "connected" or "coupled" together through intermediary elements.

[0131] Any reference herein to an element using a designation such as "first," "second," etc. is not intended to limit the quantity and / or order of those elements. Rather, these designations are used as a convenient method of distinguishing between two or more elements and / or instances of an element. Also, unless otherwise stated, a set of elements can include one or more elements.

[0132] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0133] Nothing described or illustrated or shown in this application is intended to disclose to the public any element, act, feature, benefit, advantage, or equivalent, whether or not that element, act, feature, benefit, advantage, or equivalent is recited in a claim.

[0134] In the above detailed description, it can be seen that various features are grouped together in each example. This method of disclosure should not be understood as the claimed examples having more features than are expressly recited in each claim. Rather, the disclosure may include fewer features than all of the individual examples disclosed. Thus, the following claims are hereby considered incorporated into this description, with each claim standing alone as a separate example. Although each claim standing alone as a separate example, it should be noted that a dependent claim may refer to a specific combination with one or more claims within the scope of the claim, while other examples may include or include a combination of this dependent claim with the subject matter of any other dependent claim, or a combination of any feature with other dependent and independent claims. Such combinations are suggested herein unless it is expressly stated that no specific combination is intended. It is further intended that features of a claim may be included in any other independent claim, even if this claim is not directly dependent on the independent claim.

[0135] It is further noted that the methods, systems and apparatus disclosed in the present description or claims may be implemented by a device comprising means for performing the respective acts and / or functions of the disclosed methods.

[0136] Further, in some examples, an individual act may be subdivided into or include one or more partial acts, and such partial acts may be included in and become part of the disclosure of the individual act.

[0137] Although the above disclosure illustrates examples of the present disclosure, it should be noted that various modifications and changes can be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions and / or acts of the method claims according to the examples of the present disclosure described herein need not be performed in any particular order. In addition, well-known elements may not be described in detail or may be omitted so as not to obscure the relevant details of the aspects and examples disclosed herein. Furthermore, although elements of the present disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims

1. an acoustic die; a bottom mold having one or more bottom mold via holes formed on the side and top surfaces of the acoustic die, covering an acoustic dome of the acoustic die and exposing one or more bond pads of the acoustic die; one or more bottom conductors formed on the bottom mold and in the one or more bottom mold via holes to electrically couple to the one or more bond pads; one or more inductors formed in multiple layers above the bottom mold, the inductors including at least one 3D inductor, the inductors being electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that electrical signals are filtered through the acoustic die and the one or more inductors; one or more conductive pillars formed on the one or more bottom conductors; one or more top conductors formed on the one or more conductive pillars; the at least one 3D inductor comprises one or more loops formed by the one or more conductive pillars, the one or more bottom conductors, and the one or more top conductors; Radio Frequency (RF) filters.

2. an upper mold formed on the lower mold and the one or more lower conductors and encapsulating sides of the one or more conductive pillars; 10. The RF filter of claim 1, further comprising: a first passivation layer formed on the top mold, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more conductive pillars, the one or more top conductors being formed on the first passivation layer and in the one or more first passivation via holes to electrically couple to the one or more conductive pillars.

3. a second passivation layer formed on the first passivation layer and having one or more second passivation via holes exposing top surfaces of the one or more upper conductors; 3. The RF filter of claim 2, further comprising: one or more external contacts formed on the second passivation layer and in the one or more second passivation via holes for electrically coupling to the acoustic die through the at least one 3D inductor.

4. the first passivation layer is a first polyimide layer; the second passivation layer is a second polyimide layer; the one or more external contacts are formed from copper; or 4. The RF filter of claim 3, which is any combination thereof.

5. The RF filter of claim 1 , wherein the acoustic die is a bulk acoustic wave (BAW) die.

6. the one or more bottom conductors are formed from copper; and / or the one or more inductors are formed from copper; 2. The RF filter of claim 1.

7. A device comprising an RF filter according to any one of claims 1 to 6, the device being selected from the group consisting of a music player, a video player, an entertainment unit, a navigation device, a communication device, a mobile device, a mobile phone, a smartphone, a personal digital assistant, a fixed location terminal, a tablet computer, a computer, a wearable device, an Internet of Things (IoT) device, a laptop computer, a server, and a device in an automotive vehicle.

8. forming a bottom mold on the sides and top of the acoustic die, the bottom mold covering an acoustic dome of the acoustic die and having one or more bottom mold via holes exposing one or more bond pads of the acoustic die; forming one or more bottom conductors on the bottom mold and in the one or more bottom mold via holes to electrically couple to the one or more bond pads; forming one or more inductors in multiple layers over the bottom mold, the one or more inductors electrically coupled to the acoustic die via the one or more bottom conductors and the one or more bond pads such that electrical signals are filtered through the acoustic die and the one or more inductors; forming one or more conductive pillars on the one or more bottom conductors; forming one or more top conductors on the one or more conductive pillars; Including, 1. A method for manufacturing a radio frequency (RF) filter, wherein at least one 3D inductor comprises one or more loops formed by the one or more conductive pillars, the one or more bottom conductors, and the one or more top conductors.

9. forming the bottom mold and forming the one or more bottom conductors; placing the acoustic die on a reconstructed wafer; forming the lower mold over the reconstituted wafer and the acoustic die, the lower mold covering the acoustic die; forming the one or more lower mold via holes in the lower mold to expose the one or more bond pads; depositing and patterning one or more conductive materials on the bottom mold and in the one or more bottom mold via holes to form the one or more bottom conductors; The method of claim 8 , wherein the acoustic dome remains covered by the lower mold after forming the one or more upper conductors.

10. The method of claim 9 , wherein the one or more lower mold via holes are formed by laser drilling the lower mold.

11. The method of claim 9 , wherein the one or more conductive materials comprise copper.

12. forming the bottom mold and forming the one or more bottom conductors; placing the acoustic die on a reconstructed wafer; depositing and patterning photoresist over the reconstructed wafer and the acoustic die to form one or more photoresist via holes to expose the one or more bond pads, the photoresist covering the acoustic dome of the acoustic die; depositing and patterning one or more first conductive materials into the one or more photoresist via holes to form one or more bottom conductor pillars; removing the photoresist; forming the lower mold over the reconstructed wafer and the acoustic die, the lower mold covering the acoustic dome of the acoustic die, such that a top surface of the lower mold and a top surface of the one or more bottom conductor pillars are planar; and depositing and patterning one or more second conductive materials on the bottom mold and on the one or more bottom conductor pillars to form the one or more bottom conductors.

13. The method of claim 12 , wherein the one or more bottom conductors, including the bottom conductor pillar, are formed from copper.

14. forming the one or more inductors forming a top mold over the bottom mold and the one or more bottom conductors, the top mold encapsulating sides of the one or more conductive pillars; forming a first passivation layer on the upper mold, the first passivation layer having one or more first passivation via holes exposing top surfaces of the one or more conductive pillars; depositing and patterning one or more first conductive materials on the first passivation layer and in the one or more first passivation via holes to form one or more top conductors, the one or more top conductors being electrically coupled to the one or more conductive pillars; The method of claim 8.

15. forming the one or more inductors forming a second passivation layer on the first passivation layer, the second passivation layer having one or more second passivation via holes exposing top surfaces of the one or more top conductors; 15. The method of claim 14, further comprising: depositing and patterning one or more second conductive materials on the second passivation layer and in the one or more second passivation via holes to form one or more external contacts, the one or more external contacts electrically coupled to the acoustic die through the at least one 3D inductor.

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