Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.
Embodiments of this disclosure relate to multi-layer piezoelectric substrates, and more particularly to electronic packages with multi-layer a piezoelectric substrate.
Acoustic wave filters can be implemented in radio frequency electronic systems. For instance, filters in a radio frequency front end of a mobile phone can include acoustic wave filters in an electronics package. An acoustic wave filter can filter a radio frequency signal. An acoustic wave filter can be a band pass filter. A plurality of acoustic wave filters can be arranged as a multiplexer. For example, two acoustic wave filters can be arranged as a duplexer.
An acoustic wave filter can include a plurality of resonators in a package arranged to filter a radio frequency signal. Example acoustic wave filters include surface acoustic wave (SAW) filters and bulk acoustic wave (BAW) filters. A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate. The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer on which the interdigital transductor electrode is disposed.
The packaging process for multilayer piezoelectric substrate packages can apply stresses to the piezoelectric layer that can result in reliability issues including cracking of the piezoelectric layer.
Accordingly, there is a need for an electronics package with a multi-layer piezoelectric substrate (e.g., a surface acoustic wave package, such as a SAW or TCSAW package) with improved reliability that can withstand the stresses, for example during the packaging process.
In accordance with one aspect of the disclosure, electronics package with a multi-layer piezoelectric substrate has a piezoelectric layer over a substrate. The outer boundary of the piezoelectric layer is covered with a polyimide layer so that the polyimide layer is interposed between the piezoelectric layer and a metal portion (e.g., of copper (Cu)) to inhibit (e.g., prevent) stresses from the metal layer damaging the piezoelectric layer.
In accordance with one aspect of the disclosure, an electronics package with a multi-layer piezoelectric substrate has a piezoelectric layer over a substrate. The outer boundary of the piezoelectric layer is covered with a polyimide layer, and a metal layer (e.g., of copper (Cu)) of the package is set back from the piezoelectric layer to inhibit (e.g., prevent) stresses from the metal layer damaging the piezoelectric layer.
In accordance with one aspect of the disclosure, a method of making an electronics package with a multi-layer piezoelectric substrate is provided. The method includes bonding a piezoelectric layer over a substrate. The method also includes applying a polyimide layer over an outer boundary of the piezoelectric layer so that the polyimide layer is interposed between the piezoelectric layer and a metal portion (e.g., of copper (Cu)) to inhibit (e.g., prevent) stresses from the metal layer damaging the piezoelectric layer.
In accordance with one aspect of the disclosure, a packaged acoustic wave component is provided. The packaged acoustic wave component comprises an acoustic wave device including a substrate, a piezoelectric layer disposed over at least a portion of the substrate and one or more signal lines. A thermally conductive structure is attached to one or both of the substrate and the one or more signal lines, the one or more signal lines interconnecting the piezoelectric layer and the thermally conductive structure. A dielectric layer is disposed over an outer edge portion of the piezoelectric layer and interposed between the piezoelectric layer and the thermally conductive structure to thereby reduce a stress on the piezoelectric layer from the thermally conductive structure.
In accordance with another aspect of the disclosure, a radio frequency module is provided. The radio frequency module comprises a package substrate and a packaged acoustic wave component. The packaged acoustic wave component comprises an acoustic wave device including a substrate, a piezoelectric layer disposed over at least a portion of the substrate and one or more signal lines. A thermally conductive structure is attached to one or both of the substrate and the one or more signal lines, the one or more signal lines interconnecting the piezoelectric layer and the thermally conductive structure. A dielectric layer is disposed over an outer edge portion of the piezoelectric layer and interposed between the piezoelectric layer and the thermally conductive structure to thereby reduce a stress on the piezoelectric layer from the thermally conductive structure. The radio frequency module also comprises additional circuitry, the packaged acoustic wave component and additional circuitry disposed on the package substrate.
In accordance with another aspect of the disclosure, a wireless communication device is provided. The wireless communication device comprises an antenna and a front end module including one or more packaged acoustic wave components configured to filter a radio frequency signal associated with the antenna. Each packaged acoustic wave component includes an acoustic wave device including a substrate, a piezoelectric layer disposed over at least a portion of the substrate and one or more signal lines. A thermally conductive structure is attached to one or both of the substrate and the one or more signal lines, the one or more signal lines interconnecting the piezoelectric layer and the thermally conductive structure. A dielectric layer is disposed over an outer edge portion of the piezoelectric layer and interposed between the piezoelectric layer and the thermally conductive structure to thereby reduce a stress on the piezoelectric layer from the thermally conductive structure.
In accordance with another aspect of the disclosure, a method of making a packaged acoustic wave component is provided. The method includes forming an acoustic wave device including forming or providing a substrate, forming or providing a piezoelectric layer over at least a portion of the substrate, and forming or providing one or more signal lines. The method also includes forming a dielectric layer over an outer edge portion of the piezoelectric layer. The method also includes attaching a thermally conductive structure to the substrate and the one or more signal lines, the one or more signal lines interconnecting the piezoelectric layer and the thermally conductive structure, the dielectric layer interposed between the piezoelectric layer and the thermally conductive structure to thereby reduce a stress on the piezoelectric layer from the thermally conductive structure.
In accordance with another aspect of the disclosure, a method of making a radio frequency module is provided. The method comprises forming or providing a package substrate. The method also comprises forming or providing a packaged acoustic wave component. Forming or providing the packaged acoustic wave component includes forming an acoustic wave device including forming or providing a substrate, forming or providing a piezoelectric layer over at least a portion of the substrate, and forming or providing one or more signal lines. The method also includes forming a dielectric layer over an outer edge portion of the piezoelectric layer. The method also includes attaching a thermally conductive structure to the substrate and the one or more signal lines, the one or more signal lines interconnecting the piezoelectric layer and the thermally conductive structure, the dielectric layer interposed between the piezoelectric layer and the thermally conductive structure to thereby reduce a stress on the piezoelectric layer from the thermally conductive structure. The method also includes attaching additional circuitry and the packaged acoustic wave component to the package substrate.
Embodiments of this disclosure will now be described, by way of non-limiting example, with reference to the accompanying drawings.
The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings.
Acoustic wave filters can filter radio frequency (RF) signals in a variety of applications, such as in an RF front end of a mobile phone. An acoustic wave filter can be implemented with surface acoustic wave (SAW) devices. SAW devices include SAW resonators, SAW delay lines, and multi-mode SAW (MMS) filters (e.g., double mode SAW (DMS) filters). Any features of the SAW resonators and/or devices discussed herein can be implemented in any suitable SAW device.
In general, high quality factor (Q), large effective electromechanical coupling coefficient (k2), high frequency ability, and spurious free response can be significant aspects for acoustic wave elements to enable low-loss filters, delay lines, stable oscillators, and sensitive sensors.
Multi-layer piezoelectric substrate (MPS) SAW resonators can thermally insulate an interdigital transducer electrode and a piezoelectric layer. By reducing dissipative thermal impedance of the SAW device, the ruggedness and power handling can be improved.
Some MPS SAW resonators have achieved high Q by confining energy and good thermal dissipation using a silicon (Si) support layer. However, such approaches have encountered technical challenges related to undesirable higher frequency spurious responses.
Some other MPS SAW resonators have achieved high Q by confining energy and have also reduced higher frequency spurious responses. However, such approaches have encountered relatively low thermal heat dissipation.
Aspects of the present disclosure relate to SAW resonators that include a support substrate or layer (e.g., a single crystal supporting substrate), a functional layer (e.g., a dielectric layer) over the support substrate or layer, a piezoelectric layer (e.g., a lithium niobate (LN or LiNbO3) layer or a lithium tantalate (LT or LiTaO3) layer) over the functional layer, and an interdigital transducer (IDT) electrode over the piezoelectric layer. Such SAW resonators can also include a temperature compensation layer (e.g., silicon dioxide (SiO2) layer) over the IDT electrode in certain embodiments. The SAW resonators can also include an adhesion layer disposed between the support substrate and the functional layer and/or an adhesion layer between the functional layer and the piezoelectric layer, in certain applications.
SAW resonators with the functional layer and the support layer or substrate can beneficially provide a relatively high effective electromechanical coupling coefficient (k2), a relatively high quality factor (Q), a relatively high power durability and thermal dissipation, and reduced high frequency spurious responses. The high coupling coefficient (k2) can be beneficial for relatively wide bandwidth filters. The high quality factor (Q) can beneficially lead to a relatively low insertion loss. The reduced high frequency spurious may make the SAW resonators compatible with multiplexing with higher frequency bands.
In an embodiment, an MPS SAW resonator includes a piezoelectric layer over a functional layer over a silicon support substrate or layer. The silicon support substrate can reduce thermal impedance of the MPS SAW resonator. The functional layer can be a single crystal layer arranged to confine acoustic energy and lower a higher frequency spurious response. The piezoelectric layer, the functional layer, and the silicon support substrate can all be single crystal layers.
Embodiments of MPS SAW resonators (e.g., packages) will now be discussed. Any suitable principles and advantages of these MPS SAW resonators can be implemented together with each other in an MPS SAW resonator and/or in an acoustic wave filter. MPS SAW resonators (e.g., packages) disclosed herein can have lower loss than certain bulk acoustic wave devices.
With reference to
With continued reference to
The inventors have recognized that improved reliability of electronic packages with multi-layer piezoelectric substrates can be achieved by improvements in the design of the package to reduce stress on the piezoelectric structure or layer, as provided for in the implementations discussed below.
The package 100A differs from the package 100 in that the metal portion 24A is set back (e.g., spaced, separated) from the piezoelectric structure or layer 14A so that the metal portion 24A does not contact the piezoelectric structure or layer 14A in the non-electrically connected portion (or area) of the package 100A, as shown in
In the illustrated implementation, the functional layer 12A and piezoelectric layer 14A extend to the outer boundary of the support substrate 10A or street. In another implementation, the piezoelectric layer 14A (and functional layer 12A) are etched from the dicing street (e.g., section in box C of the piezoelectric layer 14A and functional layer 12A are removed) so that they do not extend to the outer boundary of the support substrate 10A. In another implementation, the piezoelectric layer 14A (and functional layer 12A) are etched to a location inward of the metal portion 24A (e.g., section in box D of the piezoelectric layer 14A and functional layer 12A are removed). The piezoelectric layer 14A (and dielectric layer 12A) can therefore have an outer edge or perimeter that is spaced from (e.g., spaced inward from) the metal portion 24A (e.g., from an inner surface of the metal portion 24A), for example by a distance of between 5 microns (0.005 mm) and 15 microns (0.015 mm), such as 5 microns, 10 microns and 15 microns. Spacing the outer edge of the piezoelectric layer 14A and of the functional layer 12A from the metal portion 24A (e.g., by removing portions in boxes C or D in
The support substrate 10A can include (e.g., be made of, consist of) silicon (Si). In another example, the substrate 10A can be made of poly-silicon. In another example, the substrate 10A can be made of amorphous silicon. In another example, the substrate 10A can be made of silicon nitride (SiN). In another example, the substrate 10A can be made of Sapphire. In another example, the substrate 10A can be made of quartz. In another example, the substrate 10A can be made of aluminum nitride (A1N). In another example, the substrate 10A can be made of polycrystalline ceramic (Mg2O4). In another implementation, the substrate 10A can be made of diamond. However, the substrate 10A can be made of other suitable high impedance materials. An acoustic impedance of the substrate 10A can be higher than an acoustic impedance of the piezoelectric structure or layer 212. In another implementation the support substrate 10A can include a multilayer structure. For example, the support substrate can have a two-layer structure with single crystal silicon (Si) and polysilicon.
The functional (e.g., temperature compensation, dielectric) structure or layer 12A can have a lower acoustic impedance than the substrate 10A. The functional structure or layer 12A can increase adhesion between the substrate 10A and the piezoelectric structure or layer 14A of the package 100A. Alternatively or additionally, the functional structure or layer 12A can increase heat dissipation of the package 100A. The functional structure or layer 12A can be made of silicon dioxide (SiO2). In some implementations, the functional structure or layer is excluded from the package 100A (e.g., the piezoelectric layer 14A is disposed on, adjacent to or in contact with the substrate 10A).
In one implementation, the piezoelectric layer 14A can be made of lithium niobate (LN or LiNbO3). In another implementation, the piezoelectric layer 14A can be made of lithium tantalate (LT or LiTaO3). One or more resonators (e.g., including an interdigital transducer (IDT) electrode 16A, for example, between two reflectors) can be disposed on (e.g., attached or mounted to) the piezoelectric layer 14A.
The package 100B differs from the package 100A in that the dielectric (e.g., polyimide) layer 29B extends along an entire perimeter (e.g., periphery) of the package 100B. As shown in
The package 100C differs from the package 100B in that the metal portion 24C is not set back (e.g., spaced) from the piezoelectric layer 14C in the non-electrically connected portion of the package 100C, as shown in
the dielectric layer 29C (e.g., of polyimide) is disposed over the piezoelectric layer 14C (e.g., interposed between the metal portion 24C and the piezoelectric layer 14C). Accordingly, the dielectric layer 29C (e.g., of polyimide) provides a buffer between the metal portion (e.g., of copper (Cu)) 24C and the piezoelectric layer 14C, which results in a reduction in stress the piezoelectric layer 14C is subjected to, as discussed further below. One of skill in the art will recognize that in other implementations the package 100C can have the piezoelectric layer 14C (and functional layer 12C) etched in the same manner described above in connection with
The electronics package with a multi-layer piezoelectric substrate (e.g., SAW component) 176 shown in
The duplexers 185A to 185N can each include two acoustic wave filters coupled to a common node. The two acoustic wave filters can be a transmit filter and a receive filter. As illustrated, the transmit filter and the receive filter can each be band pass filters arranged to filter a radio frequency signal. One or more of the transmit filters 186A1 to 186N1 can include one or more SAW resonators or packages in accordance with any suitable principles and advantages disclosed herein. Similarly, one or more of the receive filters 186A2 to 186N2 can include one or more SAW resonators in accordance with any suitable principles and advantages disclosed herein. Although
The power amplifier 187 can amplify a radio frequency signal. The illustrated switch 188 is a multi-throw radio frequency switch. The switch 188 can electrically couple an output of the power amplifier 187 to a selected transmit filter of the transmit filters 186A1 to 186N1. In some instances, the switch 188 can electrically connect the output of the power amplifier 187 to more than one of the transmit filters 186A1 to 186N1. The antenna switch 189 can selectively couple a signal from one or more of the duplexers 185A to 185N to an antenna port ANT. The duplexers 185A to 185N can be associated with different frequency bands and/or different modes of operation (e.g., different power modes, different signaling modes, etc.).
The RF front end 422 can include one or more power amplifiers, one or more low noise amplifiers, one or more RF switches, one or more receive filters, one or more transmit filters, one or more duplex filters, one or more multiplexers, one or more frequency multiplexing circuits, the like, or any suitable combination thereof. The RF front end 422 can transmit and receive RF signals associated with any suitable communication standards. The filters 423 can include SAW resonators of a SAW component or electronics package with a multi-layer piezoelectric substrate that includes any suitable combination of features discussed with reference to any embodiments discussed above.
The transceiver 424 can provide RF signals to the RF front end 422 for amplification and/or other processing. The transceiver 424 can also process an RF signal provided by a low noise amplifier of the RF front end 422. The transceiver 424 is in communication with the processor 425. The processor 425 can be a baseband processor. The processor 425 can provide any suitable base band processing functions for the wireless communication device 420. The memory 426 can be accessed by the processor 425. The memory 426 can store any suitable data for the wireless communication device 420. The user interface 427 can be any suitable user interface, such as a display with touch screen capabilities.
Although embodiments disclosed herein relate to surface acoustic wave resonators or electronics packages with a multi-layer piezoelectric substrate, any suitable principles and advantages disclosed herein can be applied to other types of acoustic wave resonators that include an IDT electrode, such as Lamb wave resonators and/or boundary wave resonators.
Any of the embodiments described above can be implemented in association with mobile devices such as cellular handsets. The principles and advantages of the embodiments can be used for any systems or apparatus, such as any uplink wireless communication device, that could benefit from any of the embodiments described herein. The teachings herein are applicable to a variety of systems. Although this disclosure includes some example embodiments, the teachings described herein can be applied to a variety of structures. Any of the principles and advantages discussed herein can be implemented in association with RF circuits configured to process signals in a frequency range from about 30 kHz to 300 GHz, such as in a frequency range from about 450 MHz to 8.5 GHz. Acoustic wave resonators and/or filters disclosed herein can filter RF signals at frequencies up to and including millimeter wave frequencies.
Aspects of this disclosure can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products such as packaged radio frequency modules and/or packaged filter components, uplink wireless communication devices, wireless communication infrastructure, electronic test equipment, etc. Examples of the electronic devices can include, but are not limited to, a mobile phone such as a smart phone, a wearable computing device such as a smart watch or an ear piece, a telephone, a television, a computer monitor, a computer, a modem, a hand-held computer, a laptop computer, a tablet computer, a microwave, a refrigerator, a vehicular electronics system such as an automotive electronics system, a stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi-functional peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” “include,” “including” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. As used herein, the term “approximately” intends that the modified characteristic need not be absolute, but is close enough so as to achieve the advantages of the characteristic. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
Moreover, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.
Number | Date | Country | |
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63266739 | Jan 2022 | US | |
63266741 | Jan 2022 | US |