Radiator layer for ultrasonic transducer
By designing a multi-electrode and piezoelectric layer radiator layer structure on a semiconductor die, the problem of difficulty in generating low-frequency sound waves in the prior art is solved, and the efficient excitation and emission of sound waves in the range of 100MHz to 300MHz is achieved, and the target medium is penetrated deeply, thereby improving the imaging resolution and application range.
Patent Information
- Application Number
- CN202380064952.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-30
- Filing Date
- 2023-09-28
- Publication Date
- 2025-04-18
AI Technical Summary
Existing semiconductor die radiators are difficult to successfully generate low-frequency sound waves and cannot penetrate deep into the fluids, tissues or other objects to be studied, limiting the usefulness of sound wave technology in industrial and medical applications.
A semiconductor die is designed, and its radiator layer structure includes multiple electrodes and piezoelectric layers. Through the periodic excitation of the electrodes and the reflection structure of the metal components, the acoustic wave reflection and attenuation in the range of 100 MHz to 300 MHz is enhanced, ensuring that the sound wave resonates in a lower frequency range and penetrates the target medium deeply.
It realizes efficient excitation and emission of sound waves in a lower frequency range (100MHz to 300MHz), penetrates the subjects under investigation, improves imaging resolution and expands the application range of sound wave technology.
Smart Images
Figure CN119855658A_ABST
Abstract
Description
Background Art
[0001] Acoustic waves are useful in a variety of applications, including industrial and medical applications. In many such applications, a transducer converts electrical signals into acoustic waves and provides the acoustic waves to a target medium (e.g., to a human body to view an organ, to a semiconductor package to determine structural integrity). The acoustic waves reflect from features in the target medium and return to the transducer, which converts the acoustic signals into electrical signals. The electrical signals are then processed by appropriate circuitry, such as a processor or microcontroller, to produce images of those features. Summary of the invention
[0002] In an example, a semiconductor die includes: a semiconductor substrate having a surface, the surface having a first surface portion and a second surface portion; and a radiator layer located on the surface. The radiator layer includes: a metal component having a first metal component portion above the first surface portion and a second metal component portion above the second surface portion, a first distance between the first metal component portion and the first surface portion, and a second distance between the second metal component portion and the second surface portion, the first distance being less than the second distance. The radiator layer includes a first electrode and a second electrode. The radiator layer includes: a piezoelectric layer extending along a length of the radiator layer and on each of the first electrode and the second electrode, the piezoelectric layer being located between the first metal component portion and the second metal component portion and the semiconductor substrate. BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Figure 1 is a block diagram of an electronic device having a radiator layer in various examples.
[0004] Figure 2 Schematic cross-sectional views of electronic devices having radiator layers in various examples.
[0005] Figure 3 Schematic cross-sectional views of electronic devices having radiator layers in various examples.
[0006] Figure 4 Schematic cross-sectional views of electronic devices having radiator layers in various examples.
[0007] Figure 5A Schematic cross-sectional views of a semiconductor die with a radiator layer in various examples.
[0008] Figure 5B Schematic cross-sectional views of a semiconductor die with a radiator layer in various examples.
[0009] Figure 5C 1 is a top view of electrically active structures in a radiator layer of a semiconductor die in various examples.
[0010] Figure 5D 1 and 2 are top views of a piezoelectric layer in a radiator layer of a semiconductor die in various examples.
[0011] Figure 5E 1 is a top view of metal features in a radiator layer of a semiconductor die in various examples.
[0012] Fig. 6A Schematic diagrams of cross-sections of semiconductor dies and acoustic wave emission patterns of the semiconductor dies in various examples.
[0013] Figure 6B FIG. 5 is a graph showing how the radiated power from a radiator layer varies with the operating frequency in different examples.
[0014] Figure 7 Schematic cross-sectional views of a semiconductor die contacting a mold compound and acoustic wave emission patterns of the semiconductor die and the mold compound in various examples.
[0015] Figure 8 Schematic cross-sectional views of a semiconductor die having a radiator layer on a matching layer in various examples.
[0016] Fig. 9 Schematic cross-sectional views of semiconductor dies having a rough surface in various examples.
[0017] Fig.10 Schematic cross-sectional views of a semiconductor die having a patterned metal layer in various examples. DETAILED DESCRIPTION
[0018] Ultrasonic devices (such as medical ultrasound machines) include semiconductor chips coupled to ultrasonic transducers that excite sound waves. The ultrasonic transducers guide sound waves toward an object (such as human or animal tissue) outside the ultrasonic device. Low-frequency (e.g., 100 to 300 MHz) sound wave technology is particularly useful for extensive penetration of the object being studied. For example, low-frequency sound waves will penetrate human and animal tissues more deeply than high-frequency sound waves. Semiconductor die radiators are generally unable to successfully generate low-frequency sound waves because the radiator architecture is not suitable for controlling and guiding such low-frequency sound waves. Therefore, such radiators excite and emit sound waves within a higher frequency range (e.g., 700 MHz), and these sound waves cannot penetrate deeply into the fluid, tissue, or other object being studied. In addition, the radiator architecture is not suitable for providing a wide frequency range (e.g., a band of 100 MHz or more), and this lack of flexibility in the sound wave frequency will hinder higher resolution in imaging and limit the usefulness of the radiator in many applications.
[0019] This description describes various examples of electronic devices, such as ultrasonic devices, that include a semiconductor die capable of exciting and emitting acoustic waves within a lower frequency range (e.g., 100 to 300 MHz (inclusive)) and within a wider bandwidth (e.g., 100 MHz or greater). More specifically, the semiconductor die includes a radiator layer structure having a piezoelectric layer in contact with a plurality of electrodes. The electrodes are alternately excited to generate acoustic waves in the piezoelectric layer. When the radiator layer begins to resonate, the metal component above the piezoelectric layer reflects frequencies within a target frequency range (e.g., 100 to 300 MHz (inclusive)) and attenuates other frequencies outside this range, thereby enhancing the acoustic waves within the target frequency range. The periodicity of the electrodes (e.g., lateral dimensions and / or spacing) and the vertical thickness of each layer in the radiator layer determine the reflected signal frequency and the attenuated signal frequency. The electrodes and the metal components are arranged in a pattern that prevents lateral leakage of the acoustic waves, and alternatively, promotes the propagation of the acoustic waves vertically through the semiconductor substrate. These acoustic waves exit the semiconductor substrate and enter space external to both the semiconductor substrate and the electronic device containing the semiconductor die. Because the radiating layer is structurally configured to generate and transmit low frequency acoustic waves (e.g., 100 to 300 MHz (inclusive)) and acoustic waves over a wide frequency range (e.g., 100 MHz or greater), the acoustic waves are able to penetrate deeply into the object of investigation, delivering images with higher resolution than would otherwise be obtained at a lower bandwidth, and expanding the application of acoustic wave technology to other applications (e.g., applications where deep acoustic wave penetration would be useful) rather than applications that might be at higher frequencies and / or lower bandwidths.
[0020] Figure 11 is a block diagram of an electronic device 100 having a radiator layer in various examples. The electronic device 100 may be any device in which acoustic wave technology is useful. Example electronic devices 100 include medical ultrasound devices, navigation devices, communication devices, imaging devices, cleaning devices, and hybrid devices. The following description assumes that the electronic device 100 has a medical ultrasound application, but the scope of this description is not limited to medical ultrasound applications. The electronic device 100 includes a printed circuit board (PCB) 102. The electronic device 100 also includes a controller 104 and a semiconductor die 106. The controller 104 and the semiconductor die 106 may be coupled to the PCB 102. In an example, the semiconductor die 106 is arranged to be flush with the surface of the electronic device 100 or within 5 mm of the surface of the electronic device 100 to facilitate the emission of acoustic waves into and reception of acoustic waves from the object being studied (e.g., human or animal tissue). As described in detail below, the semiconductor die 106 includes a semiconductor substrate and a radiator layer on the semiconductor substrate. The radiator layer is configured to excite and emit acoustic waves through the semiconductor substrate. In addition, as described below, the structure of the radiator layer is adapted to reflect acoustic waves within a relatively low frequency range (e.g., 100 MHz to 300 MHz (inclusive)) and a larger bandwidth (e.g., at least 100 MHz), thereby alleviating challenges associated with other solutions as described above.
[0021] Figure 2 1 is a schematic cross-sectional view of an electronic device 100 having a radiator layer in various examples. Figure 2 The example electronic device 100 includes a PCB 102 and a semiconductor die 106 coupled to the PCB 102. The electronic device 100 may also include a controller 104 ( Figure 1 ), but the controller 104 is not Figure 2 104. PCB 102 includes metal bonding pads 200 coupled to metal traces, which in turn are coupled to other components on PCB 102, such as controller 104. In addition, semiconductor die 106 includes a device side having metal bonding pads 202 coupled to bonding pads 200 through conductive features 204, such as solder balls. Bonding pads 202 are coupled to vias and other metallizations (not explicitly shown) in semiconductor die 106, and these vias and metallizations may be coupled to radiator layer 206 on the device side of semiconductor die 106. In this way, an electrical path is formed between radiator layer 206 and controller 104 ( Figure 1 ), thereby enabling controller 104 to control radiator layer 206 as described herein.
[0022] The portion of the semiconductor die 106 above the radiator layer 206 is a semiconductor substrate through which the radiator layer 206 transmits and receives acoustic waves. Therefore, the semiconductor substrate is adjacent to the research object 208 (e.g., human or animal tissue, fluid). The semiconductor die 106 transmits acoustic waves 210 into the research object 208 and receives reflected acoustic waves 212 from the research object 208. In an example, the acoustic waves are reflected in response to the steep impedance gradient between adjacent structures (between blood and bone). The semiconductor die 106 or another structure on the PCB 102 (such as the controller 104) is configured to characterize the research object 208 based on the acoustic waves transmitted and received by the semiconductor die 106.
[0023] Figure 3 1 is a schematic cross-sectional view of an electronic device 100 having a radiator layer in various examples. Figure 3 The example electronic device 100 includes a PCB 102 and a semiconductor die 106. Other components, such as a controller 104 ( Figure 1 ) can also be coupled to PCB102, but in Figure 3 Not explicitly shown in Figure 2 Compared to the device side of the semiconductor die 106, Figure 3 102. The device side of semiconductor die 106 of PCB 102 faces away from PCB 102. Therefore, bonding pad 202 and radiator layer 206 face away from PCB 102. Therefore, bonding wire 300 couples bonding pad 202 to conductive component 302, and conductive component 302 (e.g., lead of lead frame) is coupled to bonding pad 200 of PCB 102 by means of conductive component 304 (e.g., solder ball). Bonding wire 300 is coupled to conductive component 302 by any suitable type of bonding, such as stitch bonding. Support component 306 is coupled to support component 308 (e.g., solder ball), which in turn is coupled to PCB 102. In some examples, support components 306 and 308 are non-conductive components. In some examples, support members 306 and 308 are conductive members, wherein support member 306 is coupled to metallization within semiconductor die 106, and support member 308 is coupled to bonding pad 200 of PCB 102 (not explicitly shown below support member 308). For example, support members 306 and 308 may constitute die attach pads and may serve as ground planes. In some examples, support members 306 and 308 are metallic and therefore conductive, but are not coupled to bonding pads or other metallizations and are not configured to carry electrical signals. PCB 102 includes an aperture 310 through which acoustic waves emitted by semiconductor die 106 or reflected toward semiconductor die 106 may pass. Molding compound 312 covers portions of semiconductor die 106, bonding wire 300, conductive member 302, and support member 306. In an example, acoustic waves may extend through semiconductor substrate 314, molding compound 312, or both.
[0024] In some cases, it may be useful to block sound waves from passing through the mold compound 312 . Figure 4 1 is a schematic cross-sectional view of an electronic device 100 in various embodiments. Figure 4 The electronic device 100 includes a cover 400 (eg, composed of a semiconductor material such as silicon, a dielectric material, a metal, or an alloy) located on the radiator layer 206. Figure 4 The electronic device 100 and Figure 3 The electronic device 100 of FIG. 4 is the same as that of FIG. 4. A cavity 402 formed by empty space (eg, air) is located between the semiconductor cap 400 and the radiator layer 206. The semiconductor cap 400 and the cavity 402 provide a steep impedance gradient that blocks acoustic waves, thereby limiting acoustic wave transmission and reception to the semiconductor substrate 314.
[0025] Figure 5A 1 is a schematic cross-sectional view of a semiconductor die 106 having a radiator layer in various examples. The semiconductor die 106 includes a radiator layer 206. The radiator layer 206 includes a set of wave control structures 500 having a first pitch, a set of wave control structures 502 having a second pitch greater than the first pitch, and a set of wave control structures 504 having a third pitch greater than the first pitch. In some examples, the second and third pitches are approximately equal (within 10% of each other). In an example, the second pitch is 30% to 40% greater than the first pitch, and in an example, the third pitch is 30% to 40% greater than the first pitch. The semiconductor die 106 also includes a bonding pad 202 between the set of wave control structures 502 and the nearest edge of the semiconductor die 106, and also includes a bonding pad 202 between the set of wave control structures 504 and the nearest edge of the semiconductor die 106. The semiconductor die 106 also includes a semiconductor substrate 506 below the sets of wave control structures 500, 502, and 504. In an example, semiconductor substrate 506 includes silicon, but other semiconductors such as gallium nitride are also possible.
[0026] The operation of semiconductor die 106 is described in detail with reference to FIG5B , but generally speaking, controller 104 ( Figure 1) enables radiator layer 206 to generate acoustic waves that resonate in an operating frequency range of 100 MHz to 300 MHz (e.g., 100 MHz to 200 MHz (inclusive) or 200 MHz to 300 MHz (inclusive)) with a frequency band of 100 MHz or greater. Wave control structure sets 500, 502, and 504 are configured to reflect acoustic waves in the range of 100 MHz to 300 MHz (inclusive) and attenuate acoustic waves of other frequencies. The larger spacing of wave control structure sets 502 and 504 (relative to wave control structure set 500) reduces acoustic wave leakage in the lateral direction, and the smaller spacing of wave control structure set 500 promotes acoustic wave propagation in the vertical direction (through semiconductor substrate 506). This behavior is similar to that of radio frequency waveguides and transmission lines, where the periodicity (e.g., spacing) of wave control structures (e.g., wave control structures 502, 504) in radiator layer 206 enables acoustic waves to propagate horizontally along radiator layer 206. Changing the periodicity or spacing of the wave control structures changes the dispersion characteristics of the radiator layer 206. If the electrodes in the wave control structures are excited in an alternating manner as described herein, the radiator layer 206 will exhibit highly dispersive behavior and have a maximum acoustic wave frequency, and the radiator layer 206 will attenuate acoustic waves exceeding the maximum acoustic wave frequency. Increasing the size (e.g., vertical thickness) of the wave control structures will reduce this maximum acoustic wave frequency, and enlarging the spacing between the wave control structures in the radiator layer 206 will prevent acoustic wave propagation.
[0027] Figure 5B 2 is a schematic cross-sectional view of a semiconductor die 106 having a radiator layer 206 in various examples. Specifically, Figure 5B Adjacent wave control structures are shown, wherein the wave control structure on the left is from the wave control structure set 502 ( Figure 5A ), and the right wave control structure comes from the wave control structure set 500 ( Figure 5A). Radiator layer 206 is located on surface 550 of semiconductor substrate 506. Radiator layer 206 includes multiple structures in a stacked configuration. Specifically, radiator layer 206 includes dielectric layer 551 on surface 550, dielectric layer 552 on dielectric layer 551, and dielectric layer 553 on dielectric layer 552. Other configurations (such as a single dielectric layer instead of dielectric layers 551 to 553) may also be useful. Piezoelectric layer 554 is located on dielectric layer 553. Piezoelectric layer 554 extends along the length of surface 550, and more generally, along the length of radiator layer 206. A pair of electrodes 555 and 556 are located on opposite sides of piezoelectric layer 554, as shown. Electrode 555 is positioned between piezoelectric layer 554 and dielectric layer 553, and electrode 556 is positioned between piezoelectric layer 554 and dielectric layer 557. Dielectric layer 557 is adjacent to piezoelectric layer 554. Metal feature 558 (e.g., composed of tungsten or tungsten-titanium) is located on dielectric layer 557, and dielectric layer 559 is located on metal feature 558. Metal feature 560 (e.g., composed of tungsten or tungsten-titanium) is located on dielectric layer 559. Dielectric layer 561 is located on metal feature 560, and passivation layer 599 is located on dielectric layer 561.
[0028] As depicted, piezoelectric layer 554 extends along the length of radiator layer 206. In some examples, Figure 5B The various dielectric and passivation layers 599 may extend along the length of the radiator layer 206, but Figure 5B The various dielectric layers and passivation layer 599 may also include multiple non-continuous sections. In some examples, electrodes 555 and 556 do not extend along the full length of radiator layer 206, but have a shortened length relative to radiator layer 206, as shown. In some examples, metal features 558 and 560 do not extend along the full length of radiator layer 206, but have a shortened length relative to radiator layer 206, as shown.
[0029] Wave control structure 562 is a portion of radiator layer 206 that includes a portion of piezoelectric layer 554, a pair of electrodes 555 and 556, a pair of metal components 558 and 560, and a dielectric layer that enables electrodes 555, 556, metal components 558, 560, and piezoelectric layer 554 to be separated from each other in the manner shown. Wave control structure 562 has an arched shape because piezoelectric layer 554, a pair of metal components 558, 560, passivation layer 599, and various dielectric layers in radiator layer 206 all have an arched shape. For example, metal component 560 includes portion 563 located directly above corresponding portion 564 of surface 550; metal component 558 includes portion 565 located directly above portion 564 of surface 550 and directly below portion 563 of metal component 560; metal component 560 includes portion 566 located directly above corresponding portion 567 of surface 550; metal component 558 includes portion 568 located directly above portion 567 and directly below portion 566; metal component 560 includes portion 569 located directly above corresponding portion 570 of surface 550; and metal component 558 includes portion 571 located directly above portion 570 and directly below portion 569. In an example, the distance between portions 566 and 567 is greater than the distance between portions 563 and 564. In an example, the distance between portions 566 and 567 is greater than the distance between portions 569 and 570. In an example, the distance between portions 563 and 564 is different from the distance between portions 569 and 570 (e.g., within 10% of each other), and in some examples, the distance between portions 563 and 564 is the same as the distance between portions 569 and 570. In an example, the distance between portions 568 and 567 is greater than the distance between portions 565 and 564. In an example, the distance between portions 568 and 567 is greater than the distance between portions 571 and 570. In an example, the distance between portions 565 and 564 is different from the distance between portions 571 and 570, and in some examples, the distance between portions 565 and 564 is the same as the distance between portions 571 and 570. In an example, the piezoelectric layer 554 and the passivation layer 599 are arched in shape similar to the metal components 558 and 560.
[0030] Radiator layer 206 includes a wave control structure 572. Wave control structure 572 includes piezoelectric layer 554, passivation layer 599, and various dielectric layers 551 to 553, 557, 559, and 561. Wave control structure 572 may also include a pair of electrodes 573 and 574 on opposite sides of piezoelectric layer 554, as shown. Wave control structure 572 may also include a pair of metal components 575 and 576 above electrode 574, as shown. As shown, piezoelectric layer 554, electrodes 573 and 574, metal components 575 and 576, passivation layer 599, and dielectric layers 557, 559, and 561 have an arch shape as described above. In an example, the length of electrodes 573 and 574 (e.g., lengths in the range of 2 microns to 50 microns) is less than the length of electrodes 555 and 556 (e.g., lengths in the range of 40 microns to 90 microns), respectively. In an example, the lengths of metal features 575 and 576 (eg, lengths in a range of 2 microns to 50 microns) are smaller than the lengths of metal features 558 and 560 (eg, lengths in a range of 2 microns to 50 microns), respectively.
[0031] In operation, the controller 104 ( Figure 1 ) excite the pair of electrodes 555, 556 and the pair of electrodes 573, 574, which in turn excite the piezoelectric layer 554. The piezoelectric layer 554 provides acoustic waves in response to the excitation of the pair of electrodes 555, 556 and 573, 574. The acoustic waves propagate along the length of the radiator layer 206. The controller 104 can excite the electrodes 555, 556 and 573, 574 in any suitable manner to generate acoustic waves. In an example, the electrodes 555 and 573 are coupled to ground, and the controller 104 repeatedly excites the electrodes 556 and 574 to generate acoustic waves. In an example, the electrodes 556 and 574 are coupled to ground, and the controller 104 repeatedly excites the electrodes 555 and 573 to generate acoustic waves, but the remainder of this description assumes that the electrodes 555 and 573 are coupled to ground and the controller 104 excites the electrodes 556 and 574. The amplitude of the sound wave depends on the voltage applied by the controller 104 to the pair of electrodes 555, 556 and 573, 574. The frequency and wavelength of the sound wave depends on the frequency at which the controller 104 excites the pair of electrodes 555, 556 and 573, 574. Although this description assumes that the excitation is Figure 5B 555, 556 and 573, 574 are specifically shown in FIG, but in an example, the controller 104 excites the wave control structure sets 500, 502 and 504 ( FIG. 504 ) in any suitable mode (e.g., in an alternating mode, in a serial mode, in a group) at any suitable frequency and any suitable voltage. Figure 5A ) to produce acoustic waves having target characteristics (such as amplitude and frequency).
[0032] Still refer to Figure 5B, radiator layer 206 resonates at the operating frequency by reflecting sound waves having the operating frequency and attenuating sound waves having other frequencies. In an example, the operating frequency is in the range of 100 MHz to 300 MHz (inclusive). In an example, the operating frequency is in the range of 200 MHz to 300 MHz (inclusive). The arched structure of radiator layer 206 (e.g., the arched piezoelectric layer 554, the arched metal members 558, 560, 575 and 576, and the arched dielectrics 557, 559 and 561 in the wave control structures 562, 572) helps reflect sound waves within the operating frequency range because the arched structure is sized to be larger than the wavelength of the sound waves, thereby creating a large contrast in the geometric characteristics of radiator layer 206 (e.g., the size contrast between the wave control structure of radiator layer 206 and the portion of radiator layer 206 that does not include the wave control structure), and creating a large reflection. The arched shapes of the structures in the radiator layer 206 provide large disturbances in the path along which the sound waves propagate, thereby achieving strong sound wave reflection. These arched structures of the radiator layer 206 also help reflect sound waves within a relatively large bandwidth (e.g., 100 MHz or more) because the arched structures are geometrically large structures (relative to the wavelength of the sound waves) and are therefore able to reflect a greater number of sound wave wavelengths covering a relatively large frequency band.
[0033] Figure 5C 2 is a top view of the electro-active structures in the radiator layer 206 in various examples. Specifically, Figure 5C A plurality of bonding pads 202 are shown, which are also shown on Figures 2 to 5A As depicted, bond pads 202 are located on the device side of semiconductor die 106 so as to be accessible to bond wires, solder balls, etc. that couple bond pads 202 to other structures, such as structures on PCB 102. Figure 5C Also shown are multiple electrodes in the radiator layer 206. Specifically, Figure 5C A ground electrode 580 is shown extending along the length of the radiator layer 206, and Figure 5CAlso shown are six electrode sets 582, 584, 586, 588, 590, and 592. Electrode 582 is electrically coupled together, electrode 582 is electrically coupled together, electrode 586 is electrically coupled together, electrode 588 is electrically coupled together, electrode 590 is electrically coupled together, and electrode 592 is electrically coupled together. The electrodes in one electrode set may be arranged in an interleaved pattern with electrodes in another electrode set. For example, electrode sets 582 and 588 have interleaved electrodes, electrode sets 584 and 590 have interleaved electrodes, and electrode sets 586a and 592 have interleaved electrodes. This interleaved pattern facilitates excitation in a particular pattern, such as on an alternating basis, but controller 104 may excite the individual electrodes in any suitable pattern, as described above. Each of electrode sets 582, 584, 586, 588, 590, and 592 is coupled to a different bonding pad 202, and controller 104 ( Figure 1 ) can individually excite the corresponding electrode sets through the bonding pads. Therefore, the controller 104 can excite the electrodes in the electrode set 586 and the electrodes in the electrode set 592 in an alternating mode. In addition, the ground electrode 580 can be coupled to one or more bonding pads 202. Although Figure 5C Ground electrode 580 is shown as a continuous segment of conductive material extending along the length of radiator layer 206, but the ground electrode may be divided into multiple discrete segments, such as Figure 5B 555 and 573 are shown in FIG. Any and all such configurations for the electrodes are possible and are included within the scope of this description.
[0034] Bond pad 202, ground electrode 580, and electrode sets 582, 584, 586, 588, 590, and 592 may be located on different vertical levels of semiconductor die 106. For example, bond pad 202 may be located on the device side of semiconductor die 106, while ground electrode 580 may be located in radiator layer 206, whether above, below, or on the same vertical level as bond pad 202. Similarly, electrode sets 582, 584, 586, 588, 590, and 592 may be located in radiator layer 206, whether above, below, or on the same vertical level as bond pad 202. In an example, and as shown in FIG. Figure 5B , ground electrode 580 may be located on a different vertical level than electrode sets 582, 584, 586, 588, 590, and 592, with piezoelectric layer 554 positioned between (i) ground electrode 580 and (ii) electrode sets 582, 584, 586, 588, 590, and 592. Electrically active structures (such as electrodes and bonding pads) on different vertical levels may be coupled to one another with conductive (e.g., copper) vias as desired.
[0035] Figure 5D5 is a top view of a piezoelectric layer 554 in a radiator layer 206 in various examples. In an example, the piezoelectric layer 554 can have a length extending along the length of the radiator layer 206 and a plurality of electrodes 582, 584, 586, 588, 590, and 592 ( Figure 5C ) have the same width as the electrodes in the embodiment of the present invention, but the size of the piezoelectric layer 554 may vary.
[0036] Figure 5E FIG. 5 is a top view of a metal component 594 in the radiator layer 206 in various embodiments. The metal component 594 represents Figure 5B The upper metal components shown in FIG. 5 , such as metal components 560 and 576. Corresponding to the wave control structure 500 ( Figure 5A ) of the metal parts 594 may have a smaller spacing and correspond to the wave control structures 502 and 504 ( Figure 5A )'s metal features 594 may have a larger spacing.
[0037] Fig. 6A Schematic diagrams of cross-sections of semiconductor die 106 and acoustic wave emission patterns of semiconductor die 106 in various examples. As shown, radiator layer 206 provides acoustic waves that propagate through semiconductor substrate 506 and toward outer region 600. The acoustic waves are strongest in a central portion 602 of semiconductor substrate 506 and are weaker in lateral regions 604 and 606 of semiconductor substrate 506.
[0038] Figure 6B Graphs showing the radiated power of acoustic waves from radiator layer 206 as a function of operating frequency in different examples are shown. The x-axis shows the acoustic wave frequency in Hertz, and the y-axis shows the acoustic wave radiated power in any suitable unit, such as Watts. Although the radiated power is expressed in arbitrary units, the magnitude of the radiated power in the approximate range of 200 MHz to 300 MHz and in the broadband of approximately 100 MHz is noteworthy. Radiator layer 206 achieves a relatively strong output power of acoustic waves in a relatively low frequency range of 200 MHz to 300 MHz (including the endpoints), but the graph is merely illustrative, and depending on the specific structural geometry implemented in radiator layer 206, the output power may be increased in other frequency ranges. The structure of radiator layer 206 is configured to provide increased output power in a relatively low frequency range of 200 MHz to 300 MHz (including the endpoints), as described above.
[0039] Molding Compound 312( Figure 3 ) can make the acoustic emission pattern different from Fig. 6A The acoustic emission pattern shown in . Figure 7Schematic cross-sectional views of the mold compound 312 on the semiconductor die 106 and acoustic wave emission patterns throughout the semiconductor die 106 and the mold compound 312 in various examples. As shown, the emission pattern extends laterally in the mold compound 312 relative to the emission pattern in the semiconductor die 106.
[0040] Figure 8 800 and the radiator layer 206. The matching layer 800 is configured to perform impedance matching between the semiconductor substrate 506 and a medium (such as human tissue or fluid) on the opposite side of the matching layer 800 from the semiconductor substrate 506. The impedance gradient of the matching layer 800 can be adjusted as needed to achieve a target range of acoustic wave reflection and insertion loss. For example, the gradient of the matching layer 800 can be controlled to reduce insertion loss.
[0041] Fig. 9 900 is a cross-sectional schematic diagram of a semiconductor die 106 having a rough surface 900 in various examples. The rough surface 900 mitigates acoustic wave reflections caused by steep impedance gradients (e.g., between the semiconductor substrate 506 and the medium adjacent to the semiconductor substrate 506), thereby reducing insertion loss. In an example, the roughness of the rough surface 900 (e.g., the height of the ridges on the rough surface 900) has a range comparable to the wavelength of the acoustic waves in the semiconductor substrate 506 (e.g., in the range of 90% of the wavelength to 500% of the wavelength), because this will provide sufficient acoustic wave dispersion to scatter the acoustic waves. The roughness of the rough surface 900 becomes larger at smaller frequencies.
[0042] Fig.10 1 is a schematic cross-sectional view of a semiconductor die 106 having a patterned metal layer 1000 located on a non-device side of the semiconductor die 106 in various examples. The patterned metal layer 1000 is configured to manipulate acoustic waves propagating through the semiconductor substrate 506. For example, the patterned metal layer 1000 can be patterned to include openings 1002 to collimate acoustic waves exiting the semiconductor substrate 506. In an example, the patterned metal layer 1000 can be patterned to reduce acoustic wave reflections and accompanying insertion losses.
[0043] In this description, the term "coupled" may encompass connections, communications, or signal paths that achieve a functional relationship consistent with this description. For example, if device A generates a signal to control device B to perform an action, then: (a) in a first instance, device A is coupled to device B through a direct connection; or (b) in a second instance, device A is coupled to device B through an intermediate component C, provided that the intermediate component C does not change the functional relationship between device A and device B, so that device B is controlled by device A via the control signal generated by device A.
[0044] A device "configured to" perform a task or function may be configured (e.g., programmed and / or hardwired) to perform the function when manufactured by a manufacturer, and / or may be configured (or reconfigured) by a user after manufacture to perform the function and / or other additional or alternative functions. The configuration may be performed through firmware and / or software programming of the device, through the construction and / or layout of hardware components and interconnection of the device, or a combination thereof.
[0045] The use of the term "ground" or variations thereof in the foregoing description may include chassis ground, ground wire ground, floating ground, virtual ground, digital ground, universal ground, and / or any other form of ground connection that is applicable or suitable for the teachings of this description. Unless otherwise stated, "about," "approximately," or "substantially" preceding a parameter means within + / - 10% of the parameter. Modifications may be made in the described examples, and other examples are possible within the scope of the claims.
Claims
1. A semiconductor die, comprising: a semiconductor substrate having a surface having a first surface portion and a second surface portion; and a radiator layer located on the surface, the radiator layer comprising: a metal component having a first metal component portion above the first surface portion and a second metal component portion above the second surface portion, the first metal component portion being at a first distance from the first surface portion and the second metal component portion being at a second distance from the second surface portion, the first distance being smaller than the second distance; a first electrode and a second electrode; and A piezoelectric layer extends along the length of the radiator layer and over each of the first electrode and the second electrode, the piezoelectric layer being located between the first and second metal component portions and the semiconductor substrate. 2 . The semiconductor die of claim 1 , wherein the radiator layer is configured to emit acoustic waves having a frequency in the range of 100 MHz to 300 MHz (inclusive).
3. The semiconductor die of claim 2, wherein the acoustic waves are at least 100 MHz wide. 4 . The semiconductor die of claim 2 , wherein the radiator layer is configured to expand and contract in response to the acoustic waves.
5. The semiconductor die of claim 1 , wherein the metal component comprises a third metal component portion, the second metal component portion is located between the first metal component portion and the third metal component portion, the surface has a third surface portion, the second surface portion is located between the first surface portion and the third surface portion, and a third distance between the third metal component portion and the third surface portion is less than the second distance.
6. The semiconductor die of claim 1, wherein the first electrode and the second electrode have a first spacing therebetween, the first spacing being different from a second spacing between the second electrode and a third electrode, and the first electrode, the second electrode, and the third electrode are located on a common surface of the piezoelectric layer.
7. An electronic device, comprising: Printed circuit board (PCB); and a semiconductor die coupled to the PCB, the semiconductor die comprising: a semiconductor substrate comprising a surface having a first surface portion, a second surface portion, and an intermediate surface portion between the first surface portion and the second surface portion; and A radiator layer, which is located on the surface, the radiator layer has a sound wave control structure, and the sound wave control structure includes: a metal component having a first metal component portion, a second metal component portion, and an intermediate metal component portion between the first metal component portion and the second metal component portion, the first metal component portion, the intermediate metal component portion, and the second metal component portion being located above the first surface portion, the intermediate surface portion, and the second surface portion, respectively, and each of a first distance between the first metal component portion and the first surface portion and a second distance between the second metal component portion and the second surface portion being smaller than a third distance between the intermediate metal component portion and the intermediate surface portion; a piezoelectric layer located between the metal component and the semiconductor substrate; first and second electrodes located on opposite surfaces of the piezoelectric layer and coupled to the PCB; and A dielectric layer is located on the metal component. The electronic device according to claim 7 , wherein the first distance is within 10% of the second distance. 9 . The electronic device of claim 7 , wherein the length of the metal component is in the range of 2 μm to 90 μm (inclusive).
10. The electronic device of claim 7, wherein the first electrode and the second electrode are configured to excite the piezoelectric layer to generate an acoustic wave, and the acoustic wave has a frequency in the range of 100 MHz to 300 MHz (inclusive). 11 . The electronic device of claim 10 , wherein the sound wave is a first sound wave, and the metal component is configured to reflect the first sound wave and attenuate a second sound wave having a frequency outside the range of 100 MHz to 300 MHz. 12 . The electronic device of claim 10 , wherein the radiator layer is configured to expand and contract in response to the sound waves.
13. The electronic device of claim 7, further comprising a third electrode and a fourth electrode on the same surface of the piezoelectric layer as the first electrode, wherein a first spacing between the first electrode and the third electrode is different from a second spacing between the third electrode and a fifth electrode.
14. The electronic device of claim 7, wherein the PCB includes an aperture, and the semiconductor die is configured to transmit and receive acoustic waves through the aperture. 15 . The electronic device of claim 7 , further comprising a molding compound on the semiconductor die, wherein the radiator layer is configured to emit acoustic waves through the molding compound.
16. A semiconductor die, comprising: Semiconductor substrate; and A radiator layer, which is located on the semiconductor substrate, and includes: a first metal component and a second metal component; a first electrode and a second electrode; and A piezoelectric layer having a first side and a second side opposite to each other, wherein the piezoelectric layer is located between the first electrode and the second electrode, and the first side faces the semiconductor substrate, and the second side faces the first metal component and the second metal component, and the first electrode and the second electrode are configured to generate an acoustic wave by exciting the piezoelectric layer, and the first metal component and the second metal component are configured to reflect the acoustic wave in response to a frequency of the acoustic wave being within a target frequency band.
17. The semiconductor die of claim 16, wherein the target frequency band comprises 100 MHz to 300 MHz, inclusive.
18. The semiconductor die of claim 16, wherein the target frequency band is at least 100 MHz wide.