Dielectric shield with emi capability for pressure sensors

Abstract

The present disclosure relates to EMI capable dielectric shields for pressure sensors. Embodiments of a packaged semiconductor device and method of manufacture are provided herein, where the packaged semiconductor device comprises: a package body having a recess in which a pressure sensor is located; a polymer gel within the recess, the polymer gel longitudinally and laterally surrounding the pressure sensor; and a dielectric shield comprising at least one metal layer on a top surface of the polymer gel, wherein the dielectric shield and the polymer gel are flexible enough to transmit pressure to the pressure sensor.

Description

Technical Field

[0001] This disclosure generally relates to packaged pressure sensor devices, and more specifically, to the ability to protect circuit systems from media contamination and from electromagnetic interference (EMI). Background Technology

[0002] Pressure sensors are used in a variety of applications, such as tire pressure monitoring systems (TPMS) in vehicles. TPMS pressure sensors can be packaged together with an RF transmitter configured to transmit real-time tire pressure information from the pressure sensor to a main TPMS control unit, which in turn provides the vehicle's driver with indications (e.g., warnings) regarding the tire pressure information. Summary of the Invention

[0003] In one embodiment of this disclosure, a packaged semiconductor device is provided, the packaged semiconductor device comprising: a package body having a recess in which a pressure sensor is located; a polymer gel located within the recess, the polymer gel longitudinally and laterally surrounding the pressure sensor; and a dielectric shield including at least one metal layer on the top surface of the polymer gel, wherein the dielectric shield and the polymer gel are flexible enough to transmit pressure to the pressure sensor.

[0004] One aspect of the above embodiments is that the recess has one or more recess sidewalls, and each recess sidewall is spaced at least a minimum lateral spacing distance from an adjacent electronic component located within the recess.

[0005] Another aspect of the above embodiments is that the dielectric shield is at least spaced apart from adjacent electronic components located within the recess by a minimum longitudinal spacing distance.

[0006] Another aspect of the above embodiments is that the medium shield extends laterally across the entire top surface of the polymer gel.

[0007] Another aspect of the above embodiments is that the thickness of the dielectric shield is 5 micrometers or less.

[0008] Another aspect of the above embodiments is that the dielectric shield includes a first stainless steel layer, a copper layer, and a second stainless steel layer.

[0009] Another aspect of the above embodiments provides that the packaged semiconductor device further includes: a ground connection, at least one end of which is attached to a ground pad on the die within the recess, wherein the ground connection is in electrical contact with the dielectric shield.

[0010] Another aspect of the above embodiments is that the grounding connection includes a longitudinal conductor, the upper portion of which protrudes over the dielectric shield.

[0011] Another aspect of the above embodiments is that the grounding connection includes a loop conductor with an upper portion protruding over the dielectric shield.

[0012] Another aspect of the above embodiments provides that the packaged semiconductor device further includes: a substrate embedded in the package body; and a semiconductor die attached to the substrate and embedded in the package body, wherein the substrate is one of the group comprising a multilayer substrate and a lead frame.

[0013] Another aspect of the above embodiments provides that the packaged semiconductor device further includes a cover attached to the top surface of the package body, wherein the cover includes a vent.

[0014] In another embodiment of this disclosure, a method for manufacturing a packaged semiconductor device is provided, the method comprising: assembling a semiconductor die and a substrate as part of a device structure; encapsulating the device structure using thin-film assisted molding to form a mold body having a recess; attaching a pressure sensor to an attachment surface exposed within the recess; injecting a low-viscosity polymer gel into the recess to longitudinally and laterally surround the pressure sensor; curing the low-viscosity polymer gel into a high-viscosity polymer gel; and sputtering at least one metal layer onto the top surface of the high-viscosity polymer gel, wherein the at least one metal layer and the high-viscosity polymer gel are flexible enough to transmit pressure to the pressure sensor.

[0015] One aspect of the above embodiments provides that the at least one metal layer is sputtered laterally across the entire top surface of the polymer gel.

[0016] Another aspect of the above embodiments provides that the sputtering includes: directly sputtering a first metal layer onto the top surface of the polymer gel; directly sputtering a second metal layer onto the first metal layer; and directly sputtering a third metal layer onto the second metal layer.

[0017] Another aspect of the above embodiments is that the first metal layer and the third metal layer each comprise stainless steel, and the second metal layer comprises copper.

[0018] Another aspect of the above embodiments is that the method further includes: before the encapsulation, forming a ground connection with at least one end attached to a ground pad on the die within the recess, wherein the ground connection is electrically contacted by a dielectric shield.

[0019] Another aspect of the above embodiments is that the grounding connection includes a longitudinal conductor, the upper portion of which protrudes over the dielectric shield.

[0020] Another aspect of the above embodiments is that the grounding connection includes a loop conductor with an upper portion protruding over the dielectric shield.

[0021] Another aspect of the above embodiments is that the height of the ground connection measured from the active side of the semiconductor die is equal to or less than the height of the mold body measured from the active side of the semiconductor die.

[0022] Another aspect of the above embodiments is that the method further includes: after the sputtering, attaching a cap to the top surface of the package body, wherein the cap includes vent holes. Attached Figure Description

[0023] The invention can be better understood by referring to the accompanying drawings, and many of its objects, features and advantages will become apparent to those skilled in the art.

[0024] Figure 1 and 2 This is a block diagram depicting an example packaged semiconductor device according to some embodiments of the present disclosure.

[0025] Figure 3 , 4 5, 6, 7, 8 and 9 are block diagrams depicting steps of an example process for manufacturing a packaged semiconductor device according to some embodiments of the present disclosure.

[0026] Figure 10 This is a block diagram depicting another example packaged semiconductor device according to some embodiments of the present disclosure.

[0027] This invention is illustrated by way of example and is not limited to the accompanying drawings, in which similar reference numerals denote similar elements unless otherwise specified. The elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. Detailed Implementation

[0028] The following detailed description is intended to illustrate various embodiments of the invention and should not be considered limiting.

[0029] Overview

[0030] Conventional encapsulated pressure sensor devices can be implemented using multilayer substrates or lead frames (such as square flat no-lead (QFN)). The hollow housing can be formed from a molding compound surrounding the pressure sensor on the QFN or substrate, and this hollow housing can be filled with gel to protect the pressure sensor. The pressure sensor is configured to measure pressure in the surrounding environment, where the gel transmits the pressure to the pressure sensor. However, exposing the gel to the environment includes exposing it to media, such as chemicals that introduce contaminants into the gel (e.g., fuels, transmission fluids, engine oil, salt water, chlorinated water, etc.). When such media come into direct contact with the gel, the media can diffuse through the gel and corrode and damage the electronic components within it.

[0031] This disclosure provides a dielectric shield at the interface between the gel and its surrounding environment. The dielectric shield may be a sputtered metal layer that minimizes the area of ​​the gel that the dielectric can directly contact, thus minimizing the amount of dielectric that may diffuse into the gel and reducing the likelihood of corrosion and damage to electronic components within the gel. Both the gel and the dielectric shield should be flexible enough to transmit pressure to the pressure sensor. The dielectric shield may also be grounded via longitudinal wire bonding, which also provides electromagnetic interference (EMI) protection for the circuitry.

[0032] Example Implementation

[0033] Figure 1 A cross-sectional view of an example packaged pressure sensor device 100 (also referred to as device 100) including a dielectric shield is shown. Device 100 includes a substrate 102, a semiconductor die 104, and a pressure sensor 106, having a plurality of interconnect wire bonding connections 108 and 132. The pressure sensor 106 is located within a cavity or recess 112 formed within a mold body 110 (also referred to as package body 110), wherein the pressure sensor 106 is covered (longitudinally and laterally surrounded) by a polymer gel 114. A dielectric shield 118 is formed by a sputtered metal layer on the top surface 116 of the polymer gel 114. These components are discussed further below.

[0034] Substrate 102 provides mechanical support and electrical connection for one or more electronic components, such as die 104 and pressure sensor 106. Figure 1 In the illustrated embodiment, substrate 102 is a multilayer substrate, which is made of multiple dielectric and conductive layers to form a conductive structure through the substrate. The conductive structure includes the top surface of substrate 102 (also shown as...). Figure 3 The substrate pad 122 provides an electrical connection contact surface on the top surface 304 of the substrate 102, and the bottom surface of the substrate 102 (also shown as...) provides an electrical connection contact surface. Figure 3The substrate 102 (bottom surface 302) is provided with substrate pads 128 for external connections 130 (e.g., solder balls). In other embodiments, the substrate 102 may be a lead frame having die markings 202 and a plurality of leads 204, the plurality of leads 204 providing electrical connection contact surfaces on one or more top surfaces of the leads 204, such as... Figure 2 As shown. One or more bottom surfaces of lead 204 may also provide external connectivity. The substrate 102 in the various embodiments described herein may be a multilayer substrate or a lead frame.

[0035] Semiconductor die 104 (or simply die 104) includes an active circuit system implemented on a semiconductor material (e.g., on a semiconductor wafer diced into multiple dies 104) using multiple process steps, wherein the remaining semiconductor material below or behind the active circuit system is typically referred to as bulk silicon. On the active side of die 104 (also shown as...) Figure 3 An active circuit system is implemented on the active side 308 of the die 104, and on the opposite back side (also shown as) of the die 104. Figure 3 The back side 306 of the die 104 is embodied in bulk silicon. The active circuit system includes interconnects to die pads 124, which provide electrical connection contact surfaces on the active side of the die 104. Although the portion of the die 104 below or behind the active circuit system is referred to as bulk silicon, this portion (and the entire semiconductor die 104) can be any semiconductor material or combination of materials, such as gallium arsenide, silicon germanium, silicon-on-insulator (SOI), silicon, single-crystal silicon, and combinations thereof.

[0036] Pressure sensor 106 is configured to measure pressure in an environment and output a pressure measurement signal corresponding to a pressure reading. Pressure sensor 106 may be a microelectromechanical system (MEMS) device implemented in a semiconductor material (e.g., on a semiconductor wafer diced into multiple pressure sensors 106) using multiple process steps. In some embodiments, the pressure sensor is implemented as a capacitive transducer whose capacitance varies with pressure-induced displacement between capacitor plates within the transducer, wherein the transducer converts the capacitance value into a pressure measurement signal. In other embodiments, the pressure sensor is implemented as a piezoresistive transducer whose resistance varies with pressure-induced strain on a piezoresistive element within the transducer, wherein the transducer converts the resistance value into a pressure measurement signal. Pressure sensor 106 has at least one contact pad 126 configured to output a pressure measurement signal, the at least one contact pad 126 being shown on the top surface of pressure sensor 106 (also shown as...). Figure 5On the top surface 312 of the pressure sensor 106, additional contact pads 126 are shown that can be used for bidirectional communication. Contact pads 126 provide electrical connection contact surfaces for the pressure sensor 106.

[0037] The pressure sensor 106 also has a bottom surface (shown as) Figure 5 The bottom surface 310 of the die. In the embodiment shown herein, the bottom surface of the pressure sensor 106 is attached to the active side of the die 104, wherein the die 104 is facing upwards (or face upwards) and the active side of the die 104 includes a sensor attachment area (e.g., a depopulated area) without any die pads 124, to which the pressure sensor 106 is attached. Although Figure 1 Three die pads 124 that appear to be "below" the pressure sensor 106 are shown, but these die pads are actually laterally adjacent to the pressure sensor 106 for wire bonding connections 108, as discussed below. In other embodiments, the pressure sensor 106 may instead be directly attached to the substrate 102 in a similar manner to the die 104 (e.g., the pressure sensor 106 and die 104 are laterally positioned rather than stacked) (e.g., die markings attached to a multilayer substrate or leadframe). However, attachment of the pressure sensor 106 to the active side of the die 104 may be preferred to achieve a smaller overall device footprint. Die attachment materials with adhesive properties may be used to attach the pressure sensor 106 to the die 104 (or to the substrate 102) and the die 104 to the substrate 102. Examples of die attachment materials include, but are not limited to, polymer adhesives, solder alloys, polyimides, silicones, or epoxy-based materials containing suspended fillers such as carbon nanotubes or beryllium oxide, aluminum nitride, boron nitride, or diamond powder, pastes, films, specific die-cut tapes, etc.

[0038] Wire bonding connections 132 are formed between various electrical connection contact surfaces of the substrate 102 (e.g., the top surface of the substrate pad 122 or the lead 204) and the die 104 (e.g., the top surface of the die pad 124), and wire bonding connections 108 are formed between various electrical connection contact surfaces of the die 104 and the pressure sensor 106 (e.g., the top surface of the contact pad 126). For example, wire bonding connections 132 are formed between the die pad 124 of the die 104 and the substrate pad 122 of the substrate 102 (e.g., the top surface of the contact pad 126). Figure 1 (As shown on the left and right sides), the wire bonding connection 132 can be used to provide a signal connection or a power connection. Similarly, the wire bonding connection 132 in Figure 2The diagram shows the die pad 124 of die 104 located between the lead 204 of the lead frame. As another example, a wire bonding connection 108 is formed between the contact pad 126 of the pressure sensor 106 and the die pad 124 of die 104 (e.g., ...). Figure 1 and Figure 2 As shown in the center, the wire bond connection 108 provides the pressure measurement signal output by the pressure sensor 106 to the active circuitry of the die 104. The wire bond connection 108 represents a plurality of wire bond connections 108 that can be connected between the pressure sensor 106 and the die 104, including when the die 104 and the pressure sensor 106 are positioned side-by-side. Similarly, the wire bond connection 132 represents a plurality of wire bond connections 132 that can be connected between the substrate 102 and the die 104.

[0039] The mold body 110 is formed of a sealant material that provides mechanical support and protection for the device 100. Examples of sealant materials include, but are not limited to, molding compounds based on biphenyl- or polyaromatic epoxy resins, which may or may not include fibers or fillers that provide reinforcement (e.g., glass fiber) or other beneficial aspects (e.g., thermal, physical, or electrical properties) to the mold body. The mold body 110 is typically formed over the substrate 102 and wire bonding connections 132 and around the die 104, wherein recesses or cavities 112 exist within the mold body 110, exposing the pressure sensor 106 and any wire bonding connections 108 connected to the pressure sensor 106 (e.g., any wire bonding connection 108 connecting the pressure sensor 106 to the die 104). In the embodiments discussed herein, the recesses 112 may be formed directly within the mold body 110 using a thin-film assisted molding (FAM) technique, as described below. Figure 4 Further discussion. To minimize any stress or tension placed on the pressure sensor 106 that might affect the pressure measurement signal, the sidewalls of the resulting recess 112 are spaced apart from the sidewalls of the pressure sensor 106 and any lead bonding connections 108 connected to the pressure sensor 106 (shown as...). Figure 6 The minimum lateral distance in the text is 602). The following text combines... Figure 4 Further discussion on recess 112.

[0040] The recess 112 is filled with a polymer gel 114, which covers and surrounds the pressure sensor 106 and any wire bonding connections 108 within the recess 112. The polymer gel 114 has an internal cross-linked network within the liquid, wherein the cross-linked network may be caused by physical or chemical bonds. The amount of cross-linking determines the viscosity of the polymer gel 114, wherein the polymer gel 114 can be injected into the recess 112 in a low-viscosity form (also referred to as an uncured form, a low-cross-linked form, or a liquid form) and cured into a high-viscosity form (also referred to as a cured form, a highly cross-linked form, or a gel form), as described below. Figure 7 and 8 Further discussion follows. As the viscosity of gel 114 increases during the curing process, the density of gel 114 also increases (e.g., the volume of gel 114 decreases). Once cured, polymer gel 114 has a low modulus (e.g., less than 1 MPa), which allows gel 114 to elastically deform or non-permanently deform under pressure from the environment, and its flexibility is sufficient to transmit the pressure from the environment to pressure sensor 106. Examples of polymer gel 114 include, but are not limited to, polydimethylsiloxane (e.g., silicone) or other silicone-based gels, such as fluorosilicone gels.

[0041] The dielectric shield 118 is a conformal metal layer on the top surface 116 of the polymer gel 114. The dielectric shield 118 has a thickness 120, which is thick enough to prevent dielectric permeation through the dielectric shield 118, while also being thin enough to allow the polymer gel 114 to flex, so that pressure from the environment can be transferred through the dielectric shield 118 to the polymer gel 114. For example, the thickness of the dielectric shield 118 can be in the range of 1 to 5 micrometers. (The following is in conjunction with...) Figure 9 The formation of the dielectric shield 118 will be discussed further.

[0042] exist Figure 1 In the illustrated embodiment, the dielectric shield 118 is electrically floating. In other embodiments, the dielectric shield 118 may be grounded, which provides the benefit of electromagnetic interference (EMI) shielding for the electronic components within the recess 112. Figure 2A device 200 is shown, which also includes a ground connection 208, which is a wire bond attached to a ground die pad 124 and extends longitudinally within a recess 112 to contact the dielectric shield 118. In some embodiments, the target operating range of the packaged pressure sensor device including the dielectric shield 118 may be in the low range (e.g., atmospheric pressure plus or minus 5 kPa) or the middle range (e.g., 300 to 1000 kPa) of TPMS applications. While larger pressures can be measured by the disclosed packaged pressure sensor, excessive pressure variations (e.g., up to 1500 kPa for some applications) may cause excessive flexing of the dielectric shield 118, which could lead to fatigue at the junction between the dielectric shield 118 and the ground connection 208. However, even when the ground connection 208 is no longer in contact with the shield 118, the dielectric shield 118 continues to provide dielectric protection. The following is combined with Figure 6 The formation of grounding connection 208 will be discussed further below. Figure 10 Another embodiment of the ground connection 208 involving a ring lead bonding connection is further discussed.

[0043] The device 200 is also implemented using a lead frame as a substrate 102, the lead frame including die markers 202 and leads 204. Figure 2 The diagram illustrates a representative configuration of the lead frame, while other embodiments may include lead frame configurations with different arrangements. For example, in different lead frame configurations, the lead 204 may extend beyond the lateral periphery of the mold body 110, or the die mark 108 may be positioned in a different plane from the lead 204, or the die mark 108 may be covered by the mold body 110. Similarly, as discussed above, the device 200 includes a die 104, a pressure sensor 106, lead bonding connections 108 and 132, a mold body 110, a recess 112, a gel 114, and a protective layer 120.

[0044] Figure 2Example paths of possible media exposure are also illustrated. As described above, the pressure sensor 106 of the encapsulated pressure sensor device 200 is configured to measure pressure in the environment, wherein the top surface 116 of the gel 114 is exposed to the environment and transmits pressure from the environment to the pressure sensor 106. Without the media shield 118, this environmental exposure would also allow media to be exposed to the gel 114. The media can be any chemical substance that may corrode or damage the device. Examples of media include, but are not limited to, fuels, transmission fluids, engine oil, brine, chlorinated water, soapy water, acidic liquids, etc. When such media comes into direct contact with the exposed surface 116 of the gel 114, the media can diffuse through the gel 114 and expose the electronic components within the gel 114 to contaminants that may cause corrosion and damage. The electronic components closest to the surface 116 of the gel 114 are at greater risk of this media exposure. Some example risk areas are indicated by dashed lines, such as the upper portion 210 of any wire bonding connection 108 within the gel 114 and the upper portion 212 of the pressure sensor 106.

[0045] Typically, the medium shield 118 reduces the exposed portion of the surface 116 of the gel 114 through which the medium can diffuse, thus reducing the amount of medium that can contact and diffuse into the gel 114 and ultimately reach the risk areas 210 and 212. The arrow 206 indicates the medium exposure to the device 200. In the example shown, the medium shield 118 blocks or at least redirects the medium away from the surface 116 of the gel 114. Exposure to the medium 206 is significantly reduced compared to a device without the medium shield 118, which would otherwise be exposed to the entire medium 206. By minimizing the amount of medium that contacts and diffuses into the gel 114, the likelihood of corrosion and damage occurring in the risk areas 210 and 212 is reduced.

[0046] It should be noted that the embodiments discussed herein implement various example electronic components, and additional electronic components may be included in other embodiments. In some embodiments, device 100 or 200 may further include a temperature sensor for calibrating additional readings of pressure readings, a gyroscope sensor for additional sensor data, or an antenna for transmitting data to another device. In some embodiments, a separate power source (not shown), such as a battery, may be included to power the packaged semiconductor device 100 or 200.

[0047] The active circuitry of die 104 may include a signal processing circuitry configured to receive and calibrate a pressure measurement signal to output an accurate pressure reading. For example, the signal processing circuitry may include a linearization circuitry configured to improve the linearity of the pressure measurement signal, a temperature correction circuitry configured to adjust the pressure measurement signal (e.g., when the pressure depends on temperature), and additional circuitry with configurable settings (e.g., configurable gain of a signal amplifier or configurable monitoring threshold of a signal monitor) to further adjust the pressure measurement signal to output an accurate pressure reading. In some embodiments, the pressure reading may be output at an external connection 130.

[0048] In some embodiments, the active circuitry of die 104 may include a radio frequency (RF) block implementing an RF transmitter, wherein an antenna on device 100 is configured to transmit sensor data, including pressure readings, to a main control unit. For example, device 100 and the main control unit may be implemented in a vehicle's tire pressure monitoring system (TPMS), where pressure sensor 106 is used to monitor the tire pressure of a given tire on the vehicle. Sensor data received by the TPMS main control unit may be used by vehicle control systems (such as driver assistance systems) to provide information or warnings to the driver (e.g., low tire pressure warning). In some embodiments, the sensor data transmitted to the main control unit may also include temperature readings or other data. In some embodiments, the sensor data may also include a unique identifier or serial number for pressure sensor 106, which may be associated with the location of pressure sensor 106 (e.g., a specific tire on the vehicle).

[0049] In some embodiments, the RF block may also implement an RF receiver, thereby providing transceiver functionality for bidirectional communication between the RF block and the main control unit. The RF block implements a front-end component of an RF transmitter, an RF receiver, or both, wherein the front-end component may include, but is not limited to, a transmitter power amplifier, a receiver low-noise amplifier, one or more baluns, one or more filters, circulators or other coupling devices for the antenna, impedance matching elements, oscillators, phase-locked loops, and other suitable front-end components. The front-end component of the RF block may have configurable settings to adjust the output signal for transmitting sensor data. In some embodiments, the RF block may have an operating frequency falling within a frequency band of 300 to 500 MHz, although other operating frequencies falling within other radio frequencies may be implemented in other embodiments.

[0050] The active circuitry system may further implement control logic configured to control the signal processing and RF blocks. For example, the control logic may adjust configurable settings of the signal processing circuitry system, the RF blocks, or both to achieve accurate pressure readings. In embodiments where the RF blocks implement RF receivers, the control logic may receive information from a main control unit used to control configurable settings of the signal processing circuitry system, the RF blocks, or both.

[0051] Figure 3-9 Cross-sectional views are shown of the various steps of an example method for manufacturing a packaged pressure sensor device, performed on the device structure, wherein... Figure 10 Another device embodiment (e.g., with or without ground connection 208) that can be implemented in any of the above embodiments is shown. The intermediate device structure shown in the following figures includes the components discussed above, which represent components that may be included in different device embodiments, possibly having component layouts different from those shown in the following figures. In some embodiments, the device structure is implemented with a 9mm × 9mm footprint; in other embodiments, the footprint size may vary. The single device structure shown in the following figures may represent multiple device structures formed as an array of device structures or as part of a reassembled wafer, which are then diced into multiple package devices, wherein the various steps discussed herein are implemented on all device structures in the array. For simplicity, pads have also been omitted from the following figures.

[0052] Figure 3 An example device structure following the assembly and wire bonding steps is shown. In the illustrated embodiment, the back side 306 of die 104 is attached to the top surface 304 of substrate 102 (e.g., a die marker attached to a multilayer substrate or lead frame). The active side 308 of die 104 includes a plurality of die pads 124, which are described below in conjunction with... Figure 5 Further discussion is given of the reduced fill area (e.g., the area without die pad 124) used as the pressure sensor attachment region. Die pad 124 may be arranged on the active side 308 in a layout implementing one or more regular patterns such as rows, or one or more irregular patterns, or both. Wire bonding connections 108 are formed between the die pad 124 of the die 104 and the substrate pad 122 (in other embodiments, the substrate pad 122 may be a lead 204).

[0053] Figure 4The device structure following an encapsulation step is shown, in which a mold body 110 is formed above a substrate 102 and around a portion of a die 104. In the illustrated embodiment, a recess 112 is formed simultaneously with the mold body 110 using FAM technology. For example, the device structure is placed within the mold, and a plunger member positions the thin film on a pressure sensor assembly region (where the pressure sensor 106 is subsequently placed). In the illustrated embodiment, the pressure sensor assembly region 402 is located on the active side 308 of the die 104 and includes both a reduced fill region for attaching the pressure sensor 106 and a fill region including a die pad 124 on which a wire bonding connection 108 will be formed. In other embodiments, the pressure sensor assembly region 402 may be located on the top surface 304 of the substrate 102 (e.g., on a multilayer substrate or on a die mark of a leadframe). In an embodiment where the pressure sensor 106 is placed directly on the substrate 102, the pressure sensor assembly region 402 also includes a portion of the active side of the die 104, the portion including the die pad 124 on which wire bonding connections 108 will be formed.

[0054] The plunger is large enough to encompass the pressure sensor assembly area 402. As discussed further below, area 402 serves as the space occupied by or forming the pressure sensor 106, any wire bonding connection 108, and any ground connection 208 (if present). The plunger member keeps the diaphragm in contact with the active side 308 of the die 104, wherein the diaphragm also extends upward within the mold, thereby forming the boundary of the sidewall 404 of the recess 112. When a molding compound is injected or otherwise introduced into the mold, the diaphragm acts as a barrier preventing any molding compound from reaching the volume above area 402. The molding compound is then cured or otherwise configured to form the mold body 110, and the plunger member and diaphragm are removed from the resulting recess 112. Once the plunger member is removed, area 402 is exposed within the recess 112. For example, in the illustrated embodiment, region 402 outlines an exposed portion of the active side 308, which serves as the attachment surface for the pressure sensor 106 and wire bonding connections 108 (and 208, if present). In embodiments where the pressure sensor 106 is placed directly on the substrate 102, region 402 outlines an exposed portion of the top side 304 of the substrate 102 (e.g., the top side of a multilayer substrate or the die marking 202 of a lead frame), which serves as the attachment surface for the pressure sensor 106 and wire bonding connections 108 (and 208, if present).

[0055] Furthermore, in the illustrated embodiment, the recess sidewall 404 is formed at a positive angle (e.g., an angle outward from the center of recess 112), but in other embodiments, the recess sidewall 404 may also be formed as a vertical sidewall. Region 402 is also large enough to ensure a minimum lateral distance 602 is achieved between the sidewall 404 and any intended location of an electrical component (such as pressure sensor 106 or any wire bonding connection 108) to minimize any exposure of pressure sensor 106 to stress or tension from the rigid molding compound that would otherwise affect the pressure measurement signal of pressure sensor 106. A minimum lateral distance 602 may also be achieved between the sidewall 404 and ground connection 208 (if present) to minimize any stress or tension from the rigid molding compound placed on ground connection 208.

[0056] Figure 5 The device structure is shown after another assembly step, which attaches the pressure sensor 106 to an attachment surface exposed within the recess 112. In the illustrated embodiment, the bottom surface 310 of the pressure sensor 106 is attached to an exposed portion of the active side 308 of the die 104, such as within the reduced-fill region of the active side 308 in region 402. In other embodiments, the bottom surface 310 of the pressure sensor 106 may instead be attached directly to an exposed portion of the top surface 304 of the substrate 102 (e.g., to a die mark on a multilayer substrate or lead frame) in a similar manner to the die 104 (e.g., the pressure sensor 106 and the die 104 are laterally positioned rather than stacked). In other embodiments, the pressure sensor 106 may be configured as a flip-chip sensor, wherein the bottom surface 310 is the active side of the pressure sensor 106 having one or more contact pads 126 that can be attached to die pads 124 on the active side 308 of the semiconductor die 104 via bumps or pillars, thereby eliminating the need for wire bonding connections 108 formed between the pressure sensor 106 and the semiconductor die 104. Typically, the pressure sensor 106 occupies less space than the underlying die 104 and can be attached to any suitable location (or pressure sensor attachment area) on the die 104.

[0057] Figure 6 The device structure following another wire bonding step is shown. A wire bonding connection 108 is formed between the contact pad 126 of the pressure sensor 106 and the die pad 124 of the die 104, both of which are exposed within the recess 112. A minimum lateral distance 602 is achieved between the recess sidewall 404 and any electrical components within the recess 112, such as the pressure sensor 106 (e.g., sidewall 502 of the pressure sensor 106), any wire bonding connection 108, and any ground connection 208.

[0058] In embodiments including ground connection 208 (shown in dashed outline), the wire bonding step further includes forming ground connection 208 on ground die pad 124. Ground connection 208 may be referred to as a “suspended” wire bond connection, wherein one end of the wire bond connection is attached to ground die pad 124, and the other end of the wire bond connection extends upward and terminates in the air above ground die pad 124, thereby forming a vertical wire bond connection. The length or height 604 of ground connection 208 is measured from the active side 308 of die 104 to the end of ground connection 208 in the air, and the length or height 604 is long enough to ensure that ground connection 208 contacts a portion of dielectric shield 118 once dielectric shield 118 is formed. For example, the length 604 of ground connection 208 may be greater than the intended height of dielectric shield 118 (shown as...). Figure 9 The height of the grounding connection 208 is 902 (in the middle) to ensure contact between the grounding connection 208 and the dielectric shield 118. Another embodiment of the grounding connection 208 is in Figure 10 The diagram shows a high-ring lead bonding connection, which can provide additional stability to ground connection 208 during the device manufacturing steps. Example metals for ground connection 208 include, but are not limited to, gold, copper, aluminum, and any combination thereof (which may include any combination of alloys or different metal layers). While one ground connection 208 is shown herein, ground connection 208 represents multiple ground connections 208 that may be implemented in other embodiments.

[0059] Figure 7 The device structure is shown after a low-viscosity form 702 of polymer gel 114 (also referred to as low-viscosity polymer gel 702 or low-viscosity gel 702) is injected or otherwise introduced into the recess 112. The top surface 704 of gel 702 is spaced apart from any electrical components within the recess 112 (such as the top surface of wire bonding connection 108 or pressure sensor 106) by a distance 706, a minimum longitudinal spacing 804 to be achieved within said distance 706, as described below. Figure 8 As further described herein. In embodiments including at least one ground connection 208, the low-viscosity gel 702 may completely cover the ground connection 208 or may cover most of the ground connection 208.

[0060] Figure 8The device structure is shown after the low-viscosity gel 702 is cured into a high-viscosity form of polymer gel 114 (also referred to as high-viscosity polymer gel 114 or high-viscosity gel 114). During curing, the viscosity of gel 702 increases with the formation of additional crosslinks. Due to curing, the top surface 116 may be slightly curved (e.g., in a recessed manner). In some embodiments, due to the reduction in gel volume during curing, the top portion 802 of the grounding connection 208 may be exposed through the top surface 116 of gel 114 after curing. Typically, a minimum longitudinal distance 804 is achieved between the dielectric shield 118 (e.g., measured from the bottom of the dielectric shield 118 formed on the surface 116 of gel 114) and any electrical components within the recess 112 (other than one or more grounding connections 208, if present) to prevent electrical short circuits.

[0061] Figure 9 The device structure is shown after the dielectric shield 118 has been sputtered. The dielectric shield 118 is formed by a metal layer that is conformally sputtered laterally across the entire top surface 116 of the polymer gel 114. Sputtering achieves uniform deposition across the polymer gel 114, thereby preventing the formation of holes or openings through the dielectric shield 118. In some embodiments, sputtering may be performed across the entire top surface of the device structure, including above the top inner surface of the sidewall of the recess 112 and above the top surface of the mold body 110. Sputtering is performed at room temperature, which may be approximately in the middle of the temperature operating range of the packaged pressure sensor device. The metal layer is thick enough to provide dielectric protection while being thin enough to transmit pressure from the environment to the gel 114. In embodiments including at least one ground connection 208, metal is also sputtered over the exposed portion 802 of the ground connection 208, thereby forming an electrical connection from the dielectric shield 118 to the ground die pad 124 through the ground connection 208. Examples of metals used for sputtering include, but are not limited to, stainless steel, copper, aluminum, other suitable metals, and any combination thereof (which may include any combination of alloys or different metal layers). For example, dielectric shield 118 may include a first layer of stainless steel sputtered over the entire gel 114, a second layer of copper sputtered over the entire first layer of stainless steel, and a third layer of stainless steel sputtered over the entire copper layer. Dielectric shield 118 is formed at a height 902 measured from the active side 308 of die 104 to the bottom of dielectric shield 118 (which is formed on the top surface 116 of gel 114). In embodiments including at least one ground connection 208, it may be preferred that the ground connection 208 is retained within the recess 112. In other words, the length 604 of ground connection 208 may be equal to or less than the height 904 of die body 110 measured from the active side 308 of die 104 to the top surface of die body 110. The upper portion 802 of ground connection 208 may continue to protrude over dielectric shield 118 after sputtering.

[0062] Figure 10 A device 1000, which can be implemented using a multilayer substrate or a lead frame, is shown. In the illustrated embodiment, substrate 102 is a multilayer substrate. Device 1000 includes a dielectric shield 118 formed on gel 114 and may also include a ground connection 208, as discussed above. Device 1000 also includes a cap 1002 or other protective structure attached to the top surface of mold body 110. Cap 1002 includes a vent or aperture 1004 through which ambient pressure is exposed to the dielectric shield 118, and said ambient pressure is then transmitted through gel 114 to pressure sensor 106. Figure 10 The device structure shown can be a single device or a representative device of an array or panel of devices, which can be formed using a multilayer substrate or a lead frame array.

[0063] Figure 10 Another embodiment of a ground connection 208 as a ring wire bond connection is also shown. Such a ground connection 208 is formed in which one end of the wire bond connection is attached to a first ground die pad 124, and the other end is attached to a second ground die pad 124 within region 402, wherein the apex (or peak of the ring wire bond connection) reaches a height equal to or greater than the height 1006 of the dielectric shield 118. In the illustrated embodiment, the apex of the ground connection 208 extends beyond the height 1006 of the dielectric shield 118 to ensure that the ground connection 208 contacts the dielectric shield 118, thereby exposing a portion 802 above the dielectric shield 118. Furthermore, the ground die pad 124 does not need to be connected to... Figure 10 The die pads are spaced as closely as shown. For example, in one embodiment, the ground die pads 124 may be located on different sides of the die 104 within the recess 112. The ring-shaped wire bonding connection can provide additional mechanical stability to the ground connection 208 during manufacturing steps that will cause movement of the ground connection 208. For example, the ring configuration of the ground connection 208 may be better able to withstand any lateral movement introduced by injecting gel 702 into the recess 112, which prevents misalignment of the ground connection 208, such as a "tilted" ground connection 208 with a shorter height 604 that fails to contact the dielectric shield 118. However, it should be noted that even if the ground connection 208 fails to contact the dielectric shield 118, the dielectric shield 118 continues to provide dielectric protection.

[0064] A multilayer substrate is made of multiple dielectric and conductive layers to form a conductive structure through the substrate, the conductive structure including plating, pads (e.g., pad 122), interconnects, and vias. This conductive structure is formed of a conductive material, examples of which include, but are not limited to, nickel, gold, copper, aluminum, or other suitable conductive metals or alloys of one or more suitable conductive metals. The electrical connection contact surfaces on the substrate pads may be coated with a conductive material, examples of which include nickel, gold, copper, aluminum, tin, silver, titanium, or other suitable conductive metals or alloys of one or more suitable conductive metals, to improve the "bondable" properties of the substrate pads. Examples of multilayer substrates include, but are not limited to, ball grid arrays (BGAs), pin grid arrays (PGAs), etc. Figure 1 The stacked substrate shown can be a single substrate, or it can be a substrate array comprising multiple stacked substrates or a representative substrate in a panel.

[0065] The lead frame is formed of a conductive material, examples of which include, but are not limited to, copper, nickel, or other suitable conductive materials or alloys of one or more suitable conductive materials. The electrical connection contact surfaces (and external connections) on the leads may also be coated with a conductive material, examples of which include, but are not limited to, nickel, gold, copper, aluminum, tin, or other suitable conductive metals or alloys of one or more suitable conductive materials, to improve the "bondable" properties of the leads. Figure 2 The lead frame shown can be a single lead frame or a representative lead frame in an array of lead frames that includes multiple lead frames.

[0066] Semiconductor die 104 (also simply referred to as die 104) can be formed as one of a plurality of dies implemented on a semiconductor wafer, which can be implemented using any semiconductor material or combination of materials, such as gallium arsenide, silicon germanium, silicon-on-insulator (SOI), silicon, single-crystal silicon, and combinations thereof. The active circuit system of semiconductor die 104 is formed using a series of numerous process steps applied to the semiconductor wafer, including but not limited to: depositing semiconductor materials comprising dielectric materials and metals, such as growth, oxidation, sputtering, and conformal deposition; etching semiconductor materials, such as using wet or dry etchants; planarizing semiconductor materials, such as performing chemical mechanical polishing or planarization; performing photolithography to achieve patterning, including depositing and removing photomasks or other photoresist materials; ion implantation; annealing, etc. Examples of integrated circuit components include, but are not limited to, processors, memory, logic, analog circuit systems, sensors, microelectromechanical systems (MEMS) devices, discrete devices such as resistors, inductors, capacitors, diodes, power transistors, etc. In some embodiments, the active circuit system may be a combination of the integrated circuit components listed above or may be another type of microelectronic device. In some embodiments, the active circuit system includes a laterally diffused metal-oxide-semiconductor (LDMOS) transistor.

[0067] It should be understood that a dielectric shield has been provided to date, the dielectric shield comprising at least one metal layer sputtered directly onto the top surface of a polymer gel to provide a barrier to the dielectric at the interface between the gel and the surrounding environment, wherein the dielectric shield may be connected to ground to further provide EMI shielding.

[0068] Because the apparatus for implementing this invention is largely composed of electronic components and circuits known to those skilled in the art, as explained above, the explanation of circuit details will not exceed what is deemed necessary in order to facilitate understanding and recognition of the basic concepts of the invention and to avoid obscuring the teachings of the invention or diverting attention away from them.

[0069] It should be noted that, as used herein, the term “adjacent” means “nearby” (e.g., right next to each other and without any intermediate objects), and as used herein, “laterally” means “in the lateral direction” (e.g., horizontally parallel to the plane of the substrate).

[0070] As used herein, the terms “approximately” and “about” mean a value that is close to or within an acceptable range of the indicated value, quantity, or quality, including the precise indicated value itself.

[0071] As used herein, the terms “substantially” or “basically” mean sufficient to achieve the stated purpose or value in a practical manner, taking into account any minor defects or deviations (if any) that are not significant to the stated purpose or value due to normal and expected process anomalies that may occur during device manufacturing.

[0072] Although the invention has been described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the invention as set forth in the following claims. For example, it may be possible to Figure 1 Additional or fewer electronic components may be implemented. Therefore, the specification and drawings should be considered illustrative rather than restrictive, and all such modifications are intended to be included within the scope of the invention. Any benefits, advantages, or problem solutions described herein with respect to specific embodiments are not intended to be construed as key, necessary, or essential features or elements of any or all claims.

[0073] Furthermore, the terms “front,” “back,” “top,” “bottom,” “above,” “below,” etc. (if any) used in the specification and claims are for descriptive purposes and are not necessarily used to describe unchanging relative positions. It should be understood that the terms thus used are interchangeable where appropriate, such that the embodiments of the invention described herein can operate in other orientations than those described herein or otherwise.

[0074] Furthermore, as used herein, the term "a or an" is defined as one or more. Moreover, the use of introductory phrases such as "at least one" and "one or more" in claims should not be interpreted as implying that another claim element introduced by the indefinite article "a or an" limits any particular claim containing such an introduced claim element to an invention containing only one such element, even when the same claim includes the introductory phrase "one or more" or "at least one" and indefinite articles such as "a or an". The same applies to the use of definite articles.

[0075] Unless otherwise stated, terms such as “first” and “second” are used to arbitrarily distinguish the elements described by such terms. Therefore, these terms are not necessarily intended to indicate the chronological or other priority of such elements.

Claims

1. A packaged semiconductor device, characterized in that, include: The package body has a recess, and the pressure sensor is located in the recess; A polymer gel is located within the recess, and the polymer gel longitudinally and laterally surrounds the pressure sensor; A dielectric shield comprising at least one metal layer sputtered on the top surface of the polymer gel, wherein the dielectric shield and the polymer gel are flexible enough to transmit pressure to the pressure sensor. as well as A grounding connection, at least one end of which is attached to a grounding pad on the die within the recess, wherein the grounding connection is in electrical contact with the dielectric shield, and the upper portion of the grounding connection protrudes above the dielectric shield.

2. The packaged semiconductor device according to claim 1, characterized in that, The recess has one or more recess sidewalls, and Each recess sidewall is at least spaced apart from the adjacent electronic components located within the recess by a minimum lateral spacing distance.

3. The packaged semiconductor device according to claim 1, characterized in that, The dielectric shield is at least spaced apart from the adjacent electronic components located within the recess by a minimum longitudinal spacing distance.

4. The packaged semiconductor device according to claim 1, characterized in that, The dielectric shield extends laterally across the entire top surface of the polymer gel.

5. The packaged semiconductor device according to claim 1, characterized in that, In addition, including: Substrate, which is embedded in the package body; as well as Semiconductor die, the semiconductor die being attached to the substrate and embedded in the package body, wherein The substrate is one of the groups comprising a multilayer substrate and a lead frame.

6. A method for manufacturing a packaged semiconductor device, characterized in that, The method includes: Assemble semiconductor dies and substrates as part of the device structure; The device structure is encapsulated using film-assisted molding to form a mold body with recesses; The pressure sensor is attached to the attachment surface exposed within the recess; A low-viscosity polymer gel is injected into the recess to surround the pressure sensor both longitudinally and laterally; The low-viscosity polymer gel is cured into a high-viscosity polymer gel; and At least one metal layer is sputtered onto the top surface of the high-viscosity polymer gel, wherein the flexibility of the at least one metal layer and the high-viscosity polymer gel is sufficient to transmit pressure to the pressure sensor; The method further includes: prior to the encapsulation, forming a ground connection with at least one end attached to a ground pad on the die within the recess, wherein the ground connection is electrically contacted by a dielectric shield; wherein at least one metal layer is sputtered onto the top surface of the high-viscosity polymer gel such that the upper portion of the ground connection protrudes above the metal layer.

7. The method according to claim 6, characterized in that, The sputtering includes: The first metal layer is directly sputtered onto the top surface of the polymer gel; The second metal layer is directly sputtered onto the first metal layer; and The third metal layer is sputtered directly onto the second metal layer.

8. The method according to claim 6, characterized in that, The height of the grounding connection, measured from the active side of the semiconductor die, is equal to or less than the height of the mold body, measured from the active side of the semiconductor die.

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