Interposer for transducer array

Abstract

An architecture of an electro-acoustic module (EAM (200)) of an ultrasound probe (104) is provided. In one example, an EAM (200) includes a rigid interposer (1101, 402, 402) positioned between an application specific integrated circuit (111) (ASIC (904, 708, 702, 706, 704, 600, 205)) chip of the EAM (200) and a flexible circuit interconnect (207) coupled to a connector (209) of the EAM (200), where the interposer (1101, 402) facilitates electrical interconnection between a plurality of transducer cells (810) of the EAM (200), the ASIC (904, 708, 702, 706, 704, 600, 205), and the flexible circuit interconnect (207). The interposer (1101, 402) may be electrically coupled to a flex circuit interconnect (207) at a top side (406, 408) or a bottom side (406) of the interposer (1101, 402) via an anisotropic conductive film (ACF) and / or an anisotropic conductive paste (ACP) or via a wire bond (502).

Description

Technical Field

[0001] Embodiments of the subject matter disclosed herein relate to ultrasound imaging, and in particular to ultrasound transducer array architecture and fabrication. Background Art

[0002] Ultrasonic imaging is a medical imaging technique for imaging organs and soft tissues in the human body. Ultrasonic imaging uses real-time, non-invasive high-frequency sound waves to produce a series of two-dimensional (2D) images and / or three-dimensional (3D) images. The ultrasonic transducer unit converts the ultrasonic signal into an electrical signal and / or converts the electrical signal into an ultrasonic signal. The ultrasonic transducer unit may include a traditional piezoelectric transducer and a micro-electromechanical system (MEMS) device, such as a cMUT (capacitive micro-machined ultrasonic transducer) or a pMUT (piezoelectric micro-machined ultrasonic transducer). The ultrasonic transducer unit may be assembled into an electro-acoustic module (EAM) of a transducer array. The EAM may include an application-specific integrated circuit (ASIC) chip that sends an electrical signal from the transducer unit to an ultrasonic imaging system via a flexible circuit. Due to the high complexity of the interconnection between the transducer unit, the ASIC, and the flexible circuit, the cost of the transducer array may be very high. Summary of the invention

[0003] In one embodiment, an EAM of an ultrasound probe includes: an acoustic stack including a plurality of transducer units; at least one ASIC chip; and a rigid interposer positioned between the at least one ASIC chip and a flexible circuit coupled to one or more connectors of the EAM, the interposer facilitating electrical interconnection between a plurality of internal contacts of the at least one ASIC and the flexible circuit. The transducer unit may be a conventional piezoelectric material or a MEMS device, such as a cMUT or a pMUT. The flexible circuit (e.g., a flexible organic substrate, referred to herein as a flexible circuit) may be electrically coupled to the ASIC using an anisotropic conductive film (ACF) and / or anisotropic conductive paste (ACP) or via solder balls or wire bonds. In this way, the first level interconnection of the EAM is achieved via the interposer, simplifying the output for connecting to the flexible circuit. Therefore, the complexity of the second level interconnection between the interposer and the flexible circuit may be reduced, allowing the flexible circuit to have fewer layers, thereby reducing the cost of the flexible circuit and the overall cost of the EAM.

[0004] It should be understood that the above brief description is provided to introduce in a simplified form selected concepts that are further described in the detailed description. It is not meant to identify key features or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0006] Figure 1 A block diagram of an exemplary ultrasound system that may be used for ultrasound imaging according to one or more embodiments of the present disclosure is shown;

[0007] Figure 2 An exemplary architecture of an EAM as a prior art is shown;

[0008] Figure 3 As a prior art Figure 2 The decomposition part of the EAM;

[0009] Figure 4 shows a first alternative architecture of a decomposed portion of an EAM according to one or more embodiments of the present disclosure;

[0010] Figure 5 shows a second alternative architecture of a decomposed portion of an EAM according to one or more embodiments of the present disclosure;

[0011] Figure 6 An exemplary ASIC as prior art is shown;

[0012] Figure 7 An exemplary tiled configuration of an ASIC as a prior art is shown;

[0013] Figure 8 A plurality of transducers are shown as a prior art acoustic stack;

[0014] Fig. 9 shows an exemplary interconnection between an ASIC, a transducer array, and a flexible circuit as prior art;

[0015] Fig.10 An exemplary method for assembling an EAM according to one or more embodiments of the present disclosure is shown;

[0016] Fig.11 shows a first side of an exemplary interposer according to one or more embodiments of the present disclosure; and

[0017] Fig.12 A second side of an exemplary interposer according to one or more embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0018] An ultrasound array architecture and manufacturing method are provided. An ultrasound probe may include a plurality of electro-acoustic modules (EAMs), each EAM including a plurality of transducer units and one or more dedicated application specific integrated circuit (ASIC) chips to direct electrical signals from the transducer units.

[0019] The transducer unit may be a piezoelectric ceramic, a piezoelectric single crystal, or a microelectromechanical system (MEMS) device, such as a cMUT (capacitive micromachined ultrasonic transducer) or a pMUT (piezoelectric micromachined ultrasonic transducer). A MEMS device may rely on the vibration of a membrane having a first electrode to receive and transmit signals. A MEMS device may use real-time, non-invasive high-frequency (e.g., in the range of 100 KHz to tens of MHz) sound waves to generate a series of two-dimensional (2D) images and / or three-dimensional (3D) images. The sound waves may be emitted by a transmitting transducer unit, and the reflections of the emitted sound waves may be received by a receiving transducer unit. The received sound waves may then be processed to display an image of the target. Some types of MEMS devices may be used as transmitting transducers and / or receiving transducers, such as a capacitive micromachined ultrasonic transducer (cMUT). The basic structure of a cMUT includes a thin film and a supporting substrate separated by a vacuum cavity. The membrane vibrates when excited with an electrical AC signal. Conversely, when the membrane vibrates due to an impacting sound wave, an electrical signal is generated.

[0020] To be compatible with various probe configurations and reduce development costs, the ASIC can be spliced ​​to guide a given probe. To allow this splicing, the power input and input / output (I / O) for guiding the ASIC and transducer units can be arranged on one side of the ASIC. In one example, a 2x2 ASIC configuration can guide an array of 6000 transducer units. Typically, the interconnection between these spliced ​​ASICs and the transducer units of the transducer array is performed via a flexible circuit. The flexible circuit typically includes a flexible organic substrate that allows flexible routing of electrical signals around the components of the EAM.

[0021] During assembly of the EAM, in a first step, a first set of contacts of a plurality of ASICs are interconnected with a second set of contacts of a flexible circuit. In a second step, the first set of contacts of a plurality of ASICs are interconnected with a third set of contacts of an acoustic stack including a transducer unit. Each contact of each ASIC may be individually connected to a corresponding transducer unit and a corresponding contact of the flexible circuit, resulting in a high interconnect complexity with a large number of individual connections. The high interconnect complexity may increase the cost of the EAM.

[0022] To reduce the cost of the EAM, the proposed EAM design relies on the use of an interposer with high complexity for the first level interconnection of the EAM, simplifying the output. The interposer can then be connected to the flex circuit with lower complexity, thereby producing a flex circuit with fewer layers, which is less expensive to manufacture than current transducer array designs that may rely on a flexible substrate with higher complexity. By connecting the ASIC to the flex circuit via an interposer, the overall cost of the EAM can be advantageously reduced.

[0023] Figure 1 An exemplary ultrasound system including an ultrasound probe is shown. The ultrasound probe may include multiple EAMs, each of which may have Figure 2 The architecture shown in Figure 1 is broken down into its Figure 3 , where the ASIC of the EAM can be coupled to the acoustic stack of the EAM via a flexible circuit. Figure 4 shows a proposed first alternative architecture corresponding to the decomposed part, and Figure 5 The proposed second alternative architecture corresponding to the decomposed part is shown. Figures 6 to 9 Exemplary configurations of a single ASIC, multiple spliced ​​ASICs, an acoustic stack of transducer units, and interconnections between the ASIC, acoustic stack, and flex circuits are shown, respectively. Fig.10 An exemplary method for assembling an EAM including a rigid interposer is shown. Fig.11 A first side of a rigid interposer is shown, and Fig.12 A second side of the rigid interposer is shown.

[0024] Figures 2 to 9 , Fig.11 and Fig.12 An exemplary configuration with relative positioning of various parts is shown. In at least one example, if shown as being in direct contact or directly coupled to each other, such elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. For example, parts placed in coplanar contact with each other may be referred to as being in coplanar contact. For another example, in at least one example, elements positioned to be spaced apart from each other and having only space therebetween without other parts may be described and referenced as such. For another example, elements shown as being located above / below each other, located on opposite sides of each other, or located on the left / right side of each other may be described and referenced as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the point of the element may be referred to as the "top" of the part, and the bottommost element or the point of the element may be referred to as the "bottom" of the part. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the figure, and may be used to describe the position of the elements relative to each other in the figure. Thus, in one example, elements shown as being above other elements are positioned vertically above the other elements.

[0025] Now turning to the attached figure, Figure 11 is a block diagram of an exemplary ultrasound system 100 that may be used for ultrasound imaging according to various embodiments. The ultrasound system 100 includes a transmitter 102, an ultrasound probe 104, a transmit beamformer 110, a receiver 118, a receive beamformer 120, an A / D converter 122, an RF processor 124, an RF / IQ buffer 126, a user input device 130, a signal processor 132, an image buffer 136, a display system 134, and an archive 138. The circuit 111 is a non-limiting example of a bias for a cMUT, and variations in the configuration of the circuit 111 are possible without departing from the scope of the present disclosure.

[0026] The transmitter 102 may comprise suitable logic, circuitry, interfaces and / or code that may be operable to drive the ultrasound probe 104. The ultrasound probe 104 may comprise a set of transducer elements 106, each of which may comprise, for example, a plurality of transducer units (e.g., cMUTs). The transducer elements 106 may be arranged in an EAM, such as Figure 2 , wherein each EAM includes a transducer array and at least a dedicated ASIC chip to guide the transducer signals from the transducer array. The cMUT may include, for example, a single cMUT, a 1D array of cMUTs, a 2D array of cMUTs, an annular (ring) array of cMUTs, etc. In some embodiments, the ultrasound probe 104 may be operable to acquire ultrasound image data covering, for example, at least a substantial portion of an anatomical structure such as a heart, a blood vessel, or any suitable anatomical structure. Each of the transducer elements 106 may be referred to as a channel.

[0027] The transmit beamformer 110 may include suitable logic, circuitry, interfaces, and / or code operable to control the transmitter 102, which drives the set of transmit transducer elements 106 to transmit ultrasound transmit signals into an area of ​​interest (e.g., a person, an animal, an underground cavity, a physical structure, etc.). The transmitted ultrasound signals may be backscattered from structures (such as blood cells or tissue) in the object of interest to produce echoes. The transducer elements 106 may then receive the echoes. For example, one or more drive circuits 111 may be coupled to and drive or control electrodes of each transducer element 106. For example, one or more drive circuits may be coupled to separate AC voltage sources and DC voltage sources.

[0028] The set of transducer elements 106 in the ultrasound probe 104 may be operable to convert the received echoes into analog signals and transmit to the receiver 118. Specifically, analog signals may be converted from echoes received at each of the plurality of cMUTs of the transducer element 106, and the analog signals of the plurality of cMUTs may be bundled into a single analog signal output by the transducer element 106. The receiver 118 may comprise suitable logic, circuitry, interfaces, and / or code that may be operable to receive the signals from the ultrasound probe 104. The analog signals may be transmitted to one or more of the plurality of A / D converters 122.

[0029] Thus, the ultrasound system 100 may be multiplexed so that ultrasound transmit signals are transmitted during certain time periods and echoes of these ultrasound signals are received during other time periods. Although not explicitly shown, various embodiments of the present disclosure may allow for the transmission of ultrasound signals and the reception of echoes from these signals to occur simultaneously. In such cases, the probe may include a transmitting transducer element and a receiving transducer element.

[0030] The plurality of A / D converters 122 may include suitable logic components, circuits, interfaces, and / or codes that are operable to convert analog signals from the receiver 118 into corresponding digital signals. The plurality of A / D converters 122 are disposed between the receiver 118 and the RF processor 124. Nevertheless, the present disclosure is not limited in this regard. Therefore, in some embodiments, the plurality of A / D converters 122 may be integrated within the receiver 118.

[0031] The RF processor 124 may include suitable logic components, circuits, interfaces and / or codes that are operable to demodulate the digital signals output by the plurality of A / D converters 122. According to an embodiment, the RF processor 124 may include a complex demodulator (not shown) that is operable to demodulate the digital signals to form I / Q data pairs representing corresponding echo signals. The RF data (which may be, for example, I / Q signal data, real-valued RF data, etc.) may then be transmitted to the RF / IQ buffer 126. The RF / IQ buffer 126 may include suitable logic components, circuits, interfaces and / or codes that are operable to provide temporary storage of RF or I / Q signal data generated by the RF processor 124.

[0032] Thus, various embodiments may cause, for example, the RF processor 124 to process real-valued RF data or any other equivalent representation of the data with an appropriate RF buffer 126. The receive beamformer 120 may include suitable logic, circuitry, interfaces, and / or code that may be operable to perform digital beamforming processing to, for example, sum delayed channel signals, phase-shifted channel signals, and / or weighted channel signals received from the RF processor 124 via the RF / IQ buffer 126 and output a beam summed signal. The delayed channel data, phase-shifted channel data, and / or weighted channel data may be summed to form a scan line output from the receive beamformer 120, where the scan line may be, for example, complex-valued or non-complex-valued. The specific delay of the channel may be provided, for example, by the RF processor 124 or any other processor configured to perform this task. The delayed channel data, phase-shifted channel data, and / or weighted channel data may be referred to as delay-aligned channel data.

[0033] The resulting processed information may be a beam-summed signal output from the receive beamformer 120 and transmitted to the signal processor 132. According to some embodiments, the receiver 118, the plurality of A / D converters 122, the RF processor 124, and the beamformer 120 may be integrated into a single beamformer, which may be a digital beamformer. In various embodiments, the ultrasound system 100 may include a plurality of receive beamformers 120.

[0034] The user input device 130 may be used to input patient data, scan parameters, settings, select protocols and / or templates, etc. In an exemplary embodiment, the user input device 130 is operable to configure, manage, and / or control the operation of one or more components and / or modules in the ultrasound system 100. In this regard, the user input device 130 is operable to configure, manage, and / or control the operation of the transmitter 102, the ultrasound probe 104, the transmit beamformer 110, the receiver 118, the receive beamformer 120, the RF processor 124, the RF / IQ buffer 126, the user input device 130, the signal processor 132, the image buffer 136, the display system 134, and / or the archive 138. The user input device 130 may include switches, buttons, rotary encoders, touch screens, motion tracking, voice recognition, a mouse device, a keyboard, a camera, and / or any other device capable of receiving user guidance. In certain embodiments, for example, one or more of the user input devices 130 may be integrated into other components such as the display system 134 or the ultrasound probe 104. For example, user input device 130 may include a touch screen display.

[0035] The signal processor 132 may include suitable logic components, circuits, interfaces and / or codes that are operable to process ultrasound scan data (e.g., summed IQ signals) to generate ultrasound images for presentation on a display system 134. The signal processor 132 is operable to perform one or more processing operations based on a plurality of selectable ultrasound modalities on the acquired ultrasound scan data. In an exemplary embodiment, the signal processor 132 may be used to perform display processing and / or control processing, etc. The acquired ultrasound scan data may be processed in real time during a scanning session as echo signals are received. Additionally or alternatively, the ultrasound scan data may be temporarily stored in the RF / IQ buffer 126 during a scanning session and processed in an online operation or an offline operation. In various embodiments, the processed image data may be presented at the display system 134 and / or stored at the archive 138. The archive 138 may be a local archive, a picture archiving and communication system (PACS), or any suitable device for storing images and related information.

[0036] The signal processor 132 may include one or more central processing units, microprocessors, microcontrollers, etc. For example, the signal processor 132 may be an integrated component, or may be distributed in various locations. In an exemplary embodiment, the signal processor 132 may be capable of receiving input information from the user input device 130 and / or the archive 138, generating output that may be displayed by the display system 134, and manipulating the output in response to the input information from the user input device 130, etc. For example, the signal processor 132 may be capable of executing any of the methods and / or instruction sets discussed herein according to various embodiments.

[0037] The ultrasound system 100 may be operable to continuously acquire ultrasound scan data at a frame rate suitable for the imaging situation under consideration. Typical frame rates may be in the range of 20 to 120, but may be lower or higher. The acquired ultrasound scan data may be displayed on the display system 134 at a display rate that is the same as the frame rate, or at a display rate that is slower or faster than the frame rate. An image buffer 136 is included to store processed frames of acquired ultrasound scan data that are not scheduled for immediate display. Preferably, the image buffer 136 has sufficient capacity to store frames of ultrasound scan data for at least several minutes. The frames of ultrasound scan data are stored in a manner that is easy to retrieve from them according to their acquisition order or time. The image buffer 136 may be embodied as any known data storage medium.

[0038] The display system 134 may be any device capable of conveying visual information to a user. For example, the display system 134 may include a liquid crystal display, a light emitting diode display, and / or any suitable one or more displays. The display system 134 may be operable to present an ultrasound image and / or any suitable information.

[0039] The archive 138 may be one or more computer-readable memories, such as a picture archiving and communication system (PACS), a server, a hard disk, a floppy disk, a CD, a CD-ROM, a DVD, a compact memory, a flash memory, a random access memory, a read-only memory, an electrically erasable and programmable read-only memory, and / or any suitable memory, that are integrated with the ultrasound system 100 and / or communicatively coupled (e.g., via a network) to the ultrasound system 100. The archive 138 may include, for example, a database, a library, a collection of information, or other memory that is accessed by and / or associated with the signal processor 132. For example, the archive 138 may be capable of storing data temporarily or permanently. The archive 138 may be capable of storing medical image data, data generated by the signal processor 132, and / or instructions readable by the signal processor 132, etc.

[0040] The components of the ultrasound system 100 may be implemented in software, hardware, firmware, etc. The various components of the ultrasound system 100 are communicatively connected. The components of the ultrasound system 100 may be implemented separately and / or integrated in various forms. For example, the display system 134 and the user input device 130 may be integrated as a touch screen display. In addition, although the ultrasound system 100 is described as including a receive beamformer 120, an RF processor 124, and a signal processor 132, various embodiments of the present disclosure may use various numbers of processors. For example, various devices that execute code may generally be referred to as processors. Various embodiments may refer to each of these devices including each of the RF processor 124 and the signal processor 132 as a processor. In addition, there may be other processors to additionally perform the tasks described as being performed by these devices including the receive beamformer 120, the RF processor 124, and the signal processor 132, and for ease of description, all of these processors may be referred to as "processors".

[0041] Figure 2An exemplary prior art EAM 200 is shown, which includes an acoustic stack 201, two ASICs 205, one or more flexible circuit interconnects 207, one or more connectors 209, and an acoustic backing 211. In one embodiment, the acoustic stack 201 may include one or more transducer arrays of cMUTs, pMUTs, or traditional piezoelectric elements, where the micromachined elements can be actuated by ultrasonic signals in a receive mode, or can generate ultrasonic signals when driven by appropriate electrical signals in a transmit mode. An exemplary material for cMUT elements is silicon. In another exemplary embodiment, the transducer array 201 may include an array of piezoelectric elements, where the piezoelectric material mechanically vibrates when a voltage is applied and thereby generates an ultrasonic signal, or conversely generates an electrical signal when an ultrasonic signal is projected onto the material.

[0042] Each ASIC 205 may include circuitry for driving and / or receiving signals from the acoustic stack 201, and thus may include, for example, processing, amplification, transmit, and receiver circuitry. For example, the ASIC 205 may provide electrical signals to a cMUT or piezoelectric element in a transducer array of the acoustic stack 201 to generate an ultrasonic signal, or may receive electrical signals from the transducer array when exposed to an ultrasonic signal.

[0043] Each flexible circuit interconnect 207 may include a flat flexible electrical interconnect device that includes conductive traces within a flexible insulating material such as, for example, polyimide. In this way, electrical signals may be transmitted between the connector 209 and the ASIC 205 using a flexible and configurable physical connector. In the depicted embodiment, the flexible circuit interconnect 207 includes a first wing 220 extending from the first side 206 of the EAM 200 and a second wing 222 extending from the second side 208 of the EAM 200. In other embodiments, the flexible circuit interconnect 207 may include a greater or lesser number of wings, and / or may extend over the entire length of the surface of the ASIC 205, depending on the desired configuration.

[0044] Each connector 209 may include an electrical and mechanical connector for EAM 200, wherein electrical signals may be transmitted between EAM 200 and external circuitry of an ultrasound imaging system. In addition, connector 209 may mechanically attach EAM 200 to a support structure, such as a printed circuit board or other suitable substrate.

[0045] The EAM 200 can be designed to occupy a footprint equal to or less than the active area of ​​the acoustic stack 201, thereby allowing additional EAMs to be stitched on four sides of a given EAM without significant gaps in the larger overall stitched 2D transducer array. The EAM 200 can include an acoustic backing 211 beneath the ASIC 205 to provide isolation from ultrasonic signals. Figure 2 Section 202 of Figure 3 This is shown in more detail in the exploded view 300 of FIG.

[0046] Reference now Figure 3 , an exploded view 300 of the EAM 200 is shown, wherein the exploded view 300 shows the positioning of the flexible circuit interconnect 207 relative to the acoustic stack 201 and the ASIC 205. In particular, in the interface 302 between the flexible circuit interconnect 207 and the ASIC 205, a plurality of connections 304 are shown, wherein each connection 304 connects a single ASIC contact (which leads to a single transducer element of the transducer array of the ASIC 205) to a corresponding contact on the flexible circuit interconnect 207.

[0047] from Figures 6 to 9 The arrangement of connection 304 may be understood in greater detail. Figure 6 An exemplary ASIC 600 for an EAM is shown, which may be Figure 2 and Figure 3 ASIC 600 includes a first two-dimensional (2D) array 602 of internal contacts 608 and a second 2D array 604 of output contacts 610. The internal contacts 608 may be electrically coupled to corresponding transducer cells of a transducer array positioned in an adjacent acoustic stack (e.g., acoustic stack 201).

[0048] Figure 7 An exemplary tiled ASIC configuration 700 is shown including a first ASIC 702, a second ASIC 704, a third ASIC 706, and a fourth ASIC 708 arranged in a 2x2 array. The tiled ASIC configuration 700 is depicted in a plane defined vertically by elevation angle 790 and horizontally by azimuth angle 792.

[0049] In other examples, the tiled ASIC configuration 700 may include a greater or lesser number of ASICs. For example, the tiled ASIC configuration 700 may include a 3x3 array of ASICs. Figure 7 , the output contacts of ASICs 702 and 706 (e.g., output contacts 610) are arranged within dashed box 710, while the output contacts of ASICs 704 and 708 are arranged within dashed box 712. In other embodiments, the output contacts of ASICs 702, 704, 706, and 708 may be arranged along different edges of the tiled ASIC configuration 700, such as top edge 720 and bottom edge 722.

[0050] Figure 8An exemplary acoustic stack 800 that can be electrically coupled to the tiled ASIC configuration 700 is shown. The acoustic stack 800 includes a plurality of transducer cells 810. The acoustic stack 800 can be arranged adjacent to the tiled ASIC configuration 700 such that each transducer cell 810 is aligned adjacent to a corresponding internal contact (e.g., internal contact 608) of an ASIC of the tiled ASIC configuration 700 in a manner that facilitates interconnection between each transducer cell 810 and a corresponding internal contact (e.g., internal contact 608) of an adjacent ASIC. Specifically, a first portion 802 of the transducer cell 810 can be aligned with the ASIC 702; a second portion 804 of the transducer cell 810 can be aligned with the ASIC 704; a third portion 806 of the transducer cell 810 can be aligned with the ASIC 706; and a fourth portion 808 of the transducer cell 810 can be aligned with the ASIC 708. The tiled ASIC configuration 700 also includes a first ground connection 812 and a second ground connection 814, wherein each transducer unit 802 may be electrically coupled to one of the first ground connection 812 and the second ground connection 814. Each transducer unit of the acoustic stack 800 may then be electrically coupled to a corresponding internal contact of the corresponding ASIC via a single electrical connection.

[0051] Fig. 9 A connection diagram 900 is shown, which includes an acoustic stack 902 and an ASIC 904 arranged adjacent to each other. The acoustic stack 902 may be a non-limiting example of the acoustic stack 800, and the ASIC 904 may be Figure 7 ASICs 702, 704, 706 and 708, Figure 6 ASIC 600 and Figure 2 and Figure 3 904. The acoustic stack 902 includes a plurality of ground connections 903 (e.g., the first ground connection 812 or the second ground connection 814). The ASIC 904 includes a 2D array 906 of internal contacts (e.g., the internal contact 608) and a 2D array 905 of output contacts (e.g., the output contact 610). Each transducer unit of the acoustic stack 902 can be electrically coupled to a corresponding internal contact of the 2D array 906. For example, a first transducer unit 910 of the acoustic stack 902 can be electrically coupled to a corresponding internal contact 912 of the ASIC 904, and a second transducer unit 920 of the acoustic stack 902 can be electrically coupled to a corresponding internal contact 922 of the ASIC 904. Therefore, the number of individual connections between the acoustic stack 902 and the ASIC 904 can be large.

[0052] Now back to Figure 3 , since there are a large number of electrical interconnections between the acoustic stack 201, the ASIC 205 and the flexible circuit interconnect 207, such as Figures 6 to 9As illustrated, the complexity and cost of the flexible circuit interconnect 207 may therefore be high. For example, the ASIC 205 / 904 may include 1500 transducer cells, making it almost impossible to guide each transducer cell from the external contacts (more than 1500 input / output (I / O) contacts + power and ground). As described in more detail below, in the proposed design, the transducer cells can be grouped into groups of, for example, 15 cells, where one of the functions of the ASIC is to guide each group rather than each individual cell. This reduces the number of I / Os that guide the transducer cells to 100, which can be managed more easily and at a lower cost. Therefore, in order to reduce the cost of the flexible circuit interconnect 207, alternative architectures of the EAM 200 may be used, such as Figure 4 shown.

[0053] Reference now Figure 4 , showing the corresponding Figure 3 A first alternative architecture 400 of the EAM 200 of the prior art exploded view 300 is shown. Figure 4 In the first alternative architecture 400, a plurality of electrical connections between the acoustic stack 201, the ASIC 205, and the wing 220 of the flexible circuit interconnect 207 are established via a rigid interposer 402 disposed between the acoustic stack 201 and the ASIC 205. For simplicity, the wing 220 and / or other wings of the flexible circuit interconnect 207 are not shown, but the wing 220 and / or other wings may be similarly configured. In the first alternative architecture 400, the wing 222 of the flexible circuit interconnect 207 may not be in coplanar contact with the ASIC 205, such as Figure 3 As shown. The lower surface 406 of the wing 222 of the flexible circuit interconnect 207 can be in coplanar contact with the upper surface of the top side 408 of the interposer 402. In one of the proposed configurations, the plurality of contacts 405 of the ASIC 205 can include solder bumps, and the ASIC 205 can be assembled to the interposer 402 by solder reflow. A layer of underfill 404 can be included between the interposer 402 and the ASIC 205, which can be used to mechanically strengthen the assembly and can improve the transmission of ultrasonic signals.

[0054] The interposer 402 may include a plurality of conductive traces and insulating materials for providing electrical contact between the transducer array of the acoustic stack 201 and the ASIC 205. For example, the contacts on the ASIC 205 may not be adjacent to and / or have the same location as the corresponding contacts of the transducer cells of the acoustic stack 201. The use of the interposer 402 may enable interconnection of these devices without having to design the devices with the same contact locations, thereby reducing the complexity of the EAM 200.

[0055] In various embodiments, the interposer 402 may be an organic substrate. An ideal organic substrate may have a low coefficient of thermal expansion (CTE), low cost, low development cost, and low thickness. For example, the interposer 402 may be a bismaleimide triazine (BT) substrate, for which a thickness of 0.15 mm may be achieved using four metal layers. In other embodiments, the interposer 402 may be a glass substrate or a silicon substrate having a through hole that connects a first side of the substrate to a second opposing side of the substrate, thereby allowing contact redistribution on both sides. A disadvantage of glass and silicon substrates is that their development costs may be higher than organic substrates. In addition, the thickness of the interposer may be greater (e.g., 0.4 mm).

[0056] In various embodiments, the interposer 402 may be a rigid interposer that is compatible with conventional assembly techniques for assembling the ASIC 205. In particular, the rigid interposer may be compatible with conventional widely used ASIC assembly via a reflow soldering process, which means that the solder alloy forming the contacts 405 is melted to form contacts with the interposer. Due to the rigidity of the substrate, an ASIC with solder bumps (a very conventional technique, widely used among contractors) may be assembled via reflow soldering (this is more difficult for flex circuits, as their CTE is very different from that of silicon ASICs and due to the flexibility of the flex circuits).

[0057] The interconnection between the interposer 402 and the wing 410 of the flexible circuit interconnect 207 can be established at the top side 408 of the interposer 402, where the top side 408 is located on the side of the acoustic stack 201. The advantage of forming the interconnection at the top side 408 is that, relative to Figure 3 The prior art shown (and / or elevation direction, Figure 4 450), the increase 460 in the length of the EAM 200 in the azimuthal direction (indicated by arrow 450) can be reduced and / or limited. In some embodiments, the interconnection between the interposer 402 and the wing 410 of the flexible circuit interconnect 207 can be formed using anisotropic conductive film (ACF) and / or anisotropic conductive paste (ACP), wherein the conductive particles embedded in the ACF are compressed by applying pressure during the bonding process. When the conductive particles are compressed, the conductive particles ensure that the contacts (e.g., electrodes) of the ASIC 205 (e.g., Figure 6 Conductivity between contacts 610).

[0058] Establishing interconnections through ACF / ACP can simplify the assembly of EAM 200. Such interconnections using ACF / ACP will have the advantage of limiting the azimuth length or elevation length and simplifying such assembly operations (no need for specific contact finishing on the flexible circuit and interposer). In addition, since both ACF and ACP rely on high pressure during assembly, the interposer 402 and the contacts with the flexible circuit interconnect 207 can be positioned relative to the ASIC 205 to have a flat support during assembly. For example, the coplanar contact between the contacts of the interposer 402 and the flexible circuit interconnect 207 can be positioned above the ASIC so that the ASIC provides a flat support for the application of the ACF / ACP under high pressure.

[0059] Reference now Figure 5 , showing the corresponding Figure 3 An exploded view of the EAM 200 of FIG. 300 is provided in FIG. Figure 5 , the connection between the wing 222 of the flexible circuit interconnect 207 and the interposer 402 is established via a plurality of wire bonds 502, wherein each wire bond 502 is formed between a first contact (e.g., electrode) 506 of the interposer 402 and a second contact 508 of the flexible circuit interconnect 207. The first contact 506 may be positioned at a side portion 512 of the interposer 402 proximate to the flexible circuit interconnect 207 to reduce the length of the wire bonds 502. Figure 11 to Figure 12 The side portion 512 is described in more detail. Additionally, in the second alternative architecture 500, the shape of the acoustic backing 211 can be altered to provide adequate support for the flexible circuit interconnect 207 during wire bonding. For example, a portion 510 of the acoustic backing 211 can extend below the flexible circuit interconnect 207 in the azimuthal direction 450 to provide support.

[0060] Protection for the wire bonds 502 may be provided by an encapsulant applied as a glob top 504. An advantage of the second alternative architecture 500 over the first alternative architecture 400 is that fewer contacts are established between the flexible circuit interconnect 207 and the interposer 402 because a single wire bond 502 can handle large currents (e.g., greater than 500 mA). However, more assembly steps may be performed, such as assembling the flexible circuit wings 410 to the backing 211, applying an encapsulant to the wire bonds 502 for the glob top 504, and placing a gasket 522 before applying the encapsulant to prevent leakage of the liquid encapsulant before curing. Additionally, a disadvantage of the second alternative architecture 500 is that the azimuthal length of the EAM 200 may be longer. In one example, the length of the EAM 200 of the second alternative architecture 500 may be 6 mm longer than that of the first alternative architecture 400.

[0061] Reference now Fig.10, shows the method for manufacturing a Figure 4 Alternative Architecture 400 or Figure 5 Alternative architectures 500 of EAMs (such as Figure 2 1. The method 1000 of the embodiment of the present invention is provided as a simplified method, wherein the simplified method includes steps related to the systems and methods disclosed herein, for example, including a rigid interposer that facilitates electrical connection between multiple ASICs and a flexible circuit. Therefore, other steps that are not related to the systems and methods disclosed herein when manufacturing the EAM are intentionally omitted.

[0062] Method 1000 begins at 1002, where method 1000 includes assembling a plurality of ASICs of an EAM. The ASICs may be Figure 6 and Figure 7 205 and / or ASICs 600, 702, 704, 706, and 708. In a first step, the ASICs may be assembled using solder bumps by a conventional reflow soldering process typically used in ASIC assembly. In a second step, an underfill resin may be added to fill the gap between the rigid interposer and the ASIC for acoustic purposes (transmission of ultrasonic signals). The rigid interposer may be connected to the ASIC. Figure 4 and Figure 5 The rigid interposer 402 may be the same or similar to the rigid interposer 402 of FIG. In some embodiments, the rigid interposer may include bismaleimide triazine (BT), or a different organic substrate with low CTE, low cost, low development cost, and low thickness. In other embodiments, the rigid interposer may include a glass substrate or a silicon substrate with a through hole connecting a first side of the rigid interposer with a second opposing side of the rigid interposer, thereby allowing redistribution of contacts between the first side and the second side.

[0063] Fig.11A first side 1100 of an exemplary interposer 1101 is shown, which can be a non-limiting example of a rigid interposer 402. In the depicted embodiment, the interposer 1101 is a glass interposer or a silicon interposer that includes vias connecting two sides of the interposer 1101. In other embodiments, the interposer 1101 can be a two-layer organic interposer, where the vias can connect the two sides of the interposer 1101. In still other embodiments, the interposer 1101 can be an organic interposer including more than two layers, where the vias may not connect the two sides of the interposer 1101. In the depicted example, the first side 1100 is coupled to two ASICs, where a first portion 1102 of contacts 1105 on the interposer 1101 can be connected to a first ASIC, and a second portion 1104 of contacts 1109 on the interposer 1101 can be connected to a second ASIC (e.g., the first ASIC and the second ASIC are stitched). In some examples, the first ASIC and the second ASIC can be included within a larger stitched configuration of ASICs of an EAM, such as Figure 7 The splicing configuration 700. The contact 1105 can be connected to the transducer unit via a corresponding plurality of through holes 1107, and the contact 1109 can be connected to the transducer unit via a corresponding plurality of through holes 1111.

[0064] The first side 1100 includes redistribution lines 1106 for ground connections and various other redistribution lines 1110 that can simplify interfacing with redistribution lines on the other side (e.g., Fig.12 The redistribution lines 1210) are combined with the interposer outputs (eg, Figure 4 The portion 1114 of the first side 1100 includes columns of ASIC output contacts 1112 (eg, ground, power, I / O), where each output contact 1112 may correspond to an ASIC bond pad. The portion 1114 also includes various through-holes 1108.

[0065] Returning to method 1000, at 1004, method 1000 includes coupling the rigid interposer to at least one flex circuit of the EAM (e.g., flex circuit interconnect 207), wherein the flex circuit is electrically coupled to one or more connectors of the EAM (e.g., connector 209). In some examples, the coupling between the at least one ASIC and the flex circuit can be electrically tested even before assembling the acoustic stack.

[0066] In some embodiments, a rigid interposer may be coupled to a flexible circuit using ACF / ACP, such as Figure 4The first alternative configuration of the EAM 200 is shown, which can simplify the assembly of the EAM 200, as described above. During a first coupling process using ACF / ACP, the ACF / ACP can be applied to a first set of electrodes (e.g., Fig.12 A first set of conductive particles embedded in the ACF / ACP and positioned between the first set of electrodes and the second set of electrodes may be compressed when pressure is applied, thereby allowing conduction between opposing electrode pairs of the first set of electrodes and the second set of electrodes. A second set of conductive particles embedded in the ACF / ACP and positioned around the first set of electrodes and the second set of electrodes may not be compressed and may not be conductive, thereby providing insulation between the electrode pairs. During the bonding of the rigid interposer and the flexible circuit, an ASIC and / or backing (e.g., backing 211) located underneath may be used as a flat support to facilitate the application of pressure.

[0067] In other embodiments, the rigid interposer may be coupled to the flexible circuit using a wire bonding process, such as Figure 5 A second alternative configuration of the EAM 200 is shown. During the wire bonding process, the output contacts (e.g., Fig.12 A wire bond (e.g., an output contact 1220 of the output circuit) is formed with a contact (e.g., contact 508) of the flexible circuit. Figure 5 During the wire bonding process, support for the pressure used to form the wire bonds may be provided by one or more ASICs positioned at opposite sides of the rigid interposer and / or backing material (eg, backing 211), as described above.

[0068] An advantage of the wire bonding process over using ACF / ACP is that since a single wire can accommodate large currents (e.g., continuous power greater than 500 mA), the number of contacts used to form the interconnect between the flexible circuit and the rigid interposer can be reduced. However, a disadvantage of the wire bonding process over using ACF / ACP is that more steps may be performed during the assembly of the EAM. The wire bonding process may include assembling a portion of the flexible circuit (e.g., a wing) to a backing, placing a gasket (e.g., gasket 522) to prevent leakage of the encapsulant, and then applying the encapsulant as a glob top package (e.g., glob top package 504) to cover and protect the wire bond. Another disadvantage of the wire bonding process is that the azimuthal length of the EAM may increase. In one example, the azimuthal length is increased by at least 6 mm.

[0069] Returning to method 1000, at 1006, method 1000 includes physically and electrically coupling a plurality of transducer cells of an acoustic stack of the EAM to a second opposing side of the rigid interposer. When the transducer cells are coupled to the second opposing side, an electrical connection (e.g., a through-hole connection) is established between each transducer cell on the second side of the rigid interposer and a corresponding contact of a corresponding ASIC on the first side of the rigid interposer. In other words, the transducer cells are coupled to contacts of a corresponding ASIC positioned at the opposing side of the rigid interposer via the rigid interposer, rather than via a flexible circuit as is typically done.

[0070] Fig.12 Shows Fig.11 1 , wherein the second side 1200 is coupled to an acoustic stack of the EAM (e.g., acoustic stack 201 and / or acoustic stack 800). In the depicted example, a first portion 1203 of the second side 1200 includes a plurality of contacts 1202, wherein each contact 1202 can be electrically connected to a single transducer unit of the acoustic stack. After the second side 1200 is coupled to the acoustic stack, each contact 1202 can be electrically coupled to a corresponding contact of the ASIC on the first side 1100 of the interposer 1101 through a corresponding through hole 1204.

[0071] The second portion 1205 of the second side 1200 includes a first column 1214 and a second column 1216 of interposer output contacts 1220 that can be used to interface with a flexible circuit (e.g., Figure 5 The second portion 1205 also includes various through holes 1208, redistribution lines 1206 for ground connection, and various other redistribution lines 1210, similar to Fig.11 The first side 1100. It should be understood that Fig.11 and Fig.12 The exemplary contacts, vias, lines, and other features of the interposer 1101 shown in FIG. 1 are for illustrative purposes, and other embodiments may include different arrangements and / or numbers of contacts, vias, lines, and other features without departing from the scope of the present disclosure.

[0072] Therefore, two alternative architectures for EAM are proposed, which can be achieved by imposing high complexity at the interposer level and reducing interconnect complexity elsewhere (such as by simplifying I / O contacts (e.g., Figure 6The cost of the EAM can be reduced by reducing the number of contacts 610)). In addition, the design of the flexible circuit interconnect can be simplified. The distance between the ASIC and the interposer after assembly can be increased, thereby increasing the efficiency of distributing the bottom filler. In one example, the first typical pitch of the passive components may be equal to or higher than 0.5 mm, compared to the second pitch of 0.2 mm to 0.3 mm for the proposed EAM. The proposed architecture can be applied to various types of probes with transducer matrix arrays. Alternative methods for redesigning the EAM interconnect, such as redistribution of I / O contacts via a redistribution layer (RDL) at a single ASIC level, may be more expensive and / or may not significantly simplify the output flexible circuit (e.g., I / O redundancy between ASICs). RDL at the EAM level (e.g., four ASICs in the preferred option) is potentially possible (fan-out wafer level), but is limited due to limited probe volume and 16×24 mm 2 The machining costs, technical feasibility and cost-effectiveness required for the EAM surface (in one example) may not be ideal.

[0073] A technical effect of forming interconnections between the transducer unit, ASIC contacts, and the flexible circuit of the EAM via a rigid interposer is that the cost of the EAM may be reduced and the complexity of the interconnections of the EAM may be reduced.

[0074] The present disclosure also provides support for an electroacoustic module (EAM) for an ultrasound probe, the EAM comprising: an acoustic stack comprising a plurality of transducer units; at least one application specific integrated circuit (ASIC) chip; and a rigid interposer positioned between the at least one ASIC chip and a flexible circuit coupled to one or more connectors of the EAM, the interposer facilitating electrical interconnection between a plurality of internal contacts of the at least one ASIC and the flexible circuit. In a first embodiment of the system, the rigid interposer comprises an organic substrate. In a second embodiment of the system, optionally including the first embodiment, the organic substrate is bismaleimide triazine. In a third embodiment of the system, optionally including one or both of the first and second embodiments, the rigid interposer comprises one of a glass substrate and a silicon substrate. In a fourth embodiment of the system, optionally including one or more or each of the first to third embodiments, the rigid interposer comprises a through hole connecting a first side of the rigid interposer to a second opposite side of the rigid interposer, the through hole allowing contact redistribution on both the first and second sides. In a fifth embodiment of the system, optionally including one or more or each of the first to fourth embodiments, the rigid interposer is electrically coupled to the at least one ASIC via solder bumps. In a sixth embodiment of the system, optionally including one or more or each of the first to fifth embodiments, the flexible circuit includes one or more wings arranged at one or more corresponding sides of the acoustic stack, each wing connecting a portion of the plurality of internal contacts of the at least one ASIC with a corresponding connector of the one or more connectors via the rigid interposer. In a seventh embodiment of the system, optionally including one or more or each of the first to sixth embodiments, the wing of the flexible circuit is electrically coupled to one of the bottom side of the rigid interposer and the top side of the rigid interposer, the bottom side of the rigid interposer is electrically coupled to the at least one ASIC, and the top side of the rigid interposer is electrically coupled to the transducer unit of the acoustic stack. In an eighth embodiment of the system, optionally including one or more or each of the first to seventh embodiments, the electrical interconnection between the rigid interposer and the wing of the flexible circuit includes at least one of an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP). In a ninth embodiment of the system, optionally including one or more or each of the first to eighth embodiments, the wing of the flex circuit is electrically coupled to the top side of the rigid interposer, and the coplanar contact between the contacts of the rigid interposer and the wing of the flex circuit is positioned above the at least one ASIC so that the at least one ASIC provides a flat support for applying ACF / ACP at high voltage. In a tenth embodiment of the system, optionally including one or more or each of the first to ninth embodiments, the electrical interconnection between the rigid interposer and the wing of the flex circuit includes a plurality of wire bonds.In an eleventh embodiment of the system, optionally including one or more or each of the first to tenth embodiments, the plurality of wire bonds are protected by an encapsulant applied as a glob top package. In a twelfth embodiment of the system, optionally including one or more or each of the first to eleventh embodiments, the system further comprises: a gasket is placed to prevent leakage of liquid encapsulant. In a thirteenth embodiment of the system, optionally including one or more or each of the first to twelfth embodiments, the wing of the flexible circuit is electrically coupled to the top side of the rigid interposer, and the EAM further comprises an acoustic backing assembled behind the at least one ASIC to support the wing of the flexible circuit during wire bonding.

[0075] The present disclosure also provides support for a method for assembling an electro-acoustic module (EAM) of an ultrasound probe, the method comprising: assembling at least one application specific integrated circuit (ASIC) chip of the EAM by solder bumps using a conventional reflow soldering process, coupling the at least one ASIC chip to a first side of a rigid interposer via the solder bumps, coupling a plurality of transducer units of an acoustic stack to a second opposing side of the rigid interposer, and coupling the rigid interposer to a flexible circuit coupled to a connector of the EAM, the rigid interposer facilitating electrical interconnection between a plurality of internal contacts of the at least one ASIC and the flexible circuit. In a first embodiment of the method, coupling the rigid interposer to the flexible circuit further comprises establishing interconnection between the rigid interposer and the flexible circuit using at least one of an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP). In a second embodiment of the method, optionally including the first embodiment, coupling the rigid interposer to the flexible circuit further comprises establishing interconnection between the rigid interposer and the flexible circuit via a plurality of wire bonds. In a third embodiment of the method, optionally including one or both of the first and second embodiments, the method further includes: applying an encapsulant to the plurality of wire bonds as a glob top package to protect the wire bonds. In a fourth embodiment of the method, optionally including one or more or each of the first to third embodiments, the flex circuit is electrically coupled to one of a bottom side of a rigid interposer and a top side of the rigid interposer, the bottom side of the rigid interposer is electrically coupled to at least one ASIC, and the top side of the rigid interposer is electrically coupled to a transducer unit of the acoustic stack.

[0076] The present disclosure also provides support for an electro-acoustic module (EAM) of an ultrasound probe, the EAM comprising a plurality of transducer units, at least one application-specific integrated circuit (ASIC) chip, and a flexible circuit coupled to one or more connectors of the EAM, wherein electrical interconnection between the plurality of transducer units, the corresponding plurality of internal contacts of the at least one ASIC chip, and the corresponding plurality of contacts of the flexible circuit is achieved via a rigid interposer, the rigid interposer being arranged to be in coplanar contact with the transducer units at a first surface of the rigid interposer, in coplanar contact with the at least one ASIC chip at a second surface of the rigid interposer, and in coplanar contact with the corresponding plurality of contacts of the flexible circuit at either the first surface or the second surface.

[0077] This written description uses examples to disclose the invention, including the best mode, and also to enable a person skilled in the relevant art to practice the invention, including making and using any devices or systems and performing any included methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insignificant differences from the literal language of the claims.

Claims

1. An electroacoustic module (EAM (200)) of an ultrasound probe (104), the EAM (200) comprising: An acoustic stack (201, 800, 902), the acoustic stack comprising a plurality of transducer units (810); at least one application specific integrated circuit (111) (ASIC (904, 708, 702, 706, 704, 600, 205)) chip; and A rigid interposer (1101, 402, 402) positioned between the at least one ASIC (904, 708, 702, 706, 704, 600, 205) chip and a flexible circuit (111) coupled to one or more connectors (209) of the EAM (200), the interposer (1101, 402) facilitating electrical interconnection between a plurality of internal contacts (1220, 508, 1109, 1202, 610, 1105, 405, 608) of the at least one ASIC (904, 708, 702, 706, 704, 600, 205) and the flexible circuit (111).

2. The EAM (200) of claim 1, wherein the rigid interposer (1101, 402, 402) comprises an organic substrate.

3. The EAM (200) of claim 2, wherein the organic substrate is bismaleimide triazine.

4. The EAM (200) of claim 1, wherein the rigid interposer (1101, 402, 402) comprises one of a glass substrate and a silicon substrate.

5. The EAM (200) of claim 1, wherein the rigid interposer (1101, 402, 402) comprises through-holes (1208, 1108, 1107, 1111) connecting a first side (406, 1100, 206) of the rigid interposer (1101, 402, 402) with a second (2D) opposing side (406) of the rigid interposer (1101, 402, 402), the through-holes (1208, 1108, 1107, 1111) allowing for redistribution of contacts (1202) on both the first side (406, 1100, 206) and the second (2D) side (406, 1200, 208).

6. The EAM (200) of claim 1, wherein the rigid interposer (1101, 402, 402) is electrically coupled to the at least one ASIC (904, 708, 702, 706, 704, 600, 205).

7. The EAM (200) of claim 1, wherein the flexible circuit (111) includes one or more wings arranged at one or more respective sides of the acoustic stack (201, 800, 902), each wing (220, 222, 410) connecting a portion (510, 512, 202, 1114) of the plurality of internal contacts (1220, 508, 1109, 1202, 610, 1105, 405, 608) of the at least one ASIC (904, 708, 702, 706, 704, 600, 205) to a respective connector (209) of the one or more connectors (209) via the rigid interposer (1101, 402, 402).

8. The EAM (200) of claim 7, wherein the wing (220, 222, 410) of the flexible circuit (111) is electrically coupled to one of a bottom side (406) of the rigid interposer (1101, 402, 402) and a top side (406, 408) of the rigid interposer (1101, 402, 402), the bottom side (406) of the rigid interposer (1101, 402, 402) being electrically coupled to the at least one ASIC (904, 708, 702, 706, 704, 600, 205), and the top side (406, 408) of the rigid interposer (1101, 402, 402) being electrically coupled to the transducer unit (810) of the acoustic stack (201, 800, 902).

9. The EAM (200) of claim 8, wherein the electrical interconnection between the rigid interposer (1101, 402, 402) and the wing (220, 222, 410) of the flexible circuit (111) comprises at least one of an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP).

10. The EAM (200) of claim 9, wherein the wing (220, 222, 410) of the flexible circuit (111) is electrically coupled to the top side (406, 408) of the rigid interposer (1101, 402, 402), and the rigid interposer (1101, 402, 402) is electrically coupled to the contact (106, 408) of the wing (220, 222, 410) of the flexible circuit (111). The coplanar contacts (1202) between the at least one ASIC (904, 708, 702, 706, 704, 600, 205) are positioned above the at least one ASIC (904, 708, 702, 706, 704, 600, 205) such that the at least one ASIC (904, 708, 702, 706, 704, 600, 205) provides a flat support for applying ACF / ACP under high pressure.

11. The EAM (200) of claim 8, wherein the electrical interconnection between the rigid interposer (1101, 402, 402) and the wing portion (220, 222, 410) of the flexible circuit (111) comprises a plurality of wire bonds (502).

12. The EAM (200) of claim 11, wherein the plurality of wire bonds (502) are protected by an encapsulant applied as a glob top (504).

13. The EAM (200) of claim 12, further comprising a gasket (522) placed to prevent leakage of liquid encapsulant.

14. The EAM (200) of claim 11, wherein the wings (220, 222, 410) of the flexible circuit (111) are electrically coupled to the top side (406, 408) of the rigid interposer (1101, 402, 402), and the EAM (200) further comprises an acoustic backing (211) assembled behind the at least one ASIC (904, 708, 702, 706, 704, 600, 205) to support the wings (220, 222, 410) of the flexible circuit (111) during wire bonding.

15. A method for assembling an electro-acoustic module (EAM) of an ultrasound probe, the method comprising: Assembling at least one application specific integrated circuit (ASIC) chip (1002) of the EAM via solder bumps using a conventional reflow soldering process; coupling the at least one ASIC chip to a first side of a rigid interposer via the solder bumps; coupling a plurality of transducer elements of an acoustic stack to a second opposing side of the rigid interposer (1006); as well as The rigid interposer is coupled to a flexible circuit coupled to a connector of the EAM (1004), the rigid interposer facilitating electrical interconnection between a plurality of internal contacts of the at least one ASIC and the flexible circuit.

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