Circuit board assembly and electronic equipment

Abstract

The invention relates to the technical field of electronic equipment, and discloses a circuit board assembly and electronic equipment. The circuit board assembly comprises a first substrate and a packaging module, the packaging module is arranged on the first substrate, and the packaging module comprises a second substrate and a chip arranged on the second substrate; a first dielectric layer is arranged in the first substrate, and a second dielectric layer is arranged in the second substrate; and a humidity sensor is embedded in at least one of the first dielectric layer and the second dielectric layer. According to the invention, the humidity sensor is embedded in the first substrate and / or the second substrate, so that the humidity data in the circuit board assembly can be accurately measured.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to a circuit board assembly and an electronic device. Background Technology

[0002] Humidity is a crucial indicator of the proper functioning of electronic components within electronic devices. High humidity levels inside electronic devices can lead to problems such as dendrite short-circuit failures related to electrochemical migration at the circuit board level and decreased interfacial bonding strength within the package structure. Therefore, real-time monitoring of humidity-sensitive locations within electronic devices is essential for mitigating moisture-related failures. Currently, electronic devices primarily rely on internet-based weather data for humidity information. However, this data does not accurately reflect the internal humidity of the electronic device and cannot be used to analyze related failures. Summary of the Invention

[0003] This application provides a circuit board assembly and electronic device to enable the circuit board assembly to perform accurate humidity measurement.

[0004] Firstly, this application provides a circuit board assembly including a first substrate and a packaging module. The packaging module is disposed on the first substrate and includes a second substrate and a chip disposed on the second substrate. The first substrate includes a first dielectric layer, and the second substrate includes a second dielectric layer. At least one of the first and second dielectric layers has a humidity sensor embedded within it. In this application, embedding the humidity sensor within the first and / or second substrates allows for accurate measurement of humidity data within the circuit board assembly. At the product design level, accurate measurement of humidity data within the circuit board assembly facilitates monitoring under what humidity conditions reliability issues may arise, thereby providing big data support for the reliability design of the circuit board assembly and reducing the risk of failure due to humidity issues in subsequent designs. At the product application level, obtaining accurate humidity data within electronic devices enables the devices to provide early warnings for users in high-humidity environments, reducing the risk of using electronic devices in high-humidity conditions and improving the reliability of electronic devices.

[0005] In some embodiments, the material of the first dielectric layer may be, but is not limited to, polytetrafluoroethylene (PTFE), or may also be a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyimide, etc. The material of the second dielectric layer may be, but is not limited to, polytetrafluoroethylene (PTFE), or may also be a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyimide, etc.

[0006] In some implementations, the chip may include one or more chips such as a processor chip, a memory chip, or a power management chip.

[0007] In some embodiments, a first substrate includes a first surface, and a second substrate includes a second surface. The second surface is soldered to the first surface via a plurality of solder balls to achieve an electrical connection between the package module and the first substrate. Among the solder balls, the orthographic projection of some solder balls onto the first surface lies within a first region of the first surface. Among the solder balls whose orthographic projections lie within the first region, at least one solder ball has a voltage difference greater than a first voltage difference threshold with respect to another solder ball. At least one humidity sensor embedded in a first dielectric layer has its orthographic projection onto the first surface within the first region. Since dendrites tend to grow in areas with relatively large voltage differences, by embedding a humidity sensor in the first dielectric layer at a position corresponding to the first region, the humidity of the first region can be measured more accurately using the humidity sensor. This allows for appropriate measures to be taken to reduce the humidity of the first substrate when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the first substrate.

[0008] In some embodiments, a filler adhesive layer is disposed between the first surface and the second surface. This filler adhesive layer can encapsulate solder balls and cover areas opposite to the first and second surfaces. The filler adhesive layer has void regions, and the orthographic projection of at least one humidity sensor embedded in the first dielectric layer onto the first surface at least partially coincides with the orthographic projection of the void regions onto the first surface. Dendrites tend to grow at locations on the first surface corresponding to the void regions. By embedding a humidity sensor in the first dielectric layer at the location corresponding to the void regions, the humidity of the area on the first surface corresponding to the void regions can be accurately measured. This allows for appropriate measures to be taken to reduce the humidity of the first substrate in cases of excessive humidity, thereby suppressing dendrite growth and ensuring the reliability of the first substrate.

[0009] In some implementations, among the multiple solder balls, the orthographic projection of some solder balls onto the first surface lies within a second region of the first surface, where the welding stress is greater than a first stress threshold. At least one humidity sensor embedded in the first dielectric layer has its orthographic projection onto the first surface within this second region. Areas on the first surface with high welding stress are also prone to dendrite growth. By embedding a humidity sensor in the first dielectric layer at a position corresponding to the second region, the humidity of the second region can be measured more accurately. This allows for appropriate measures to be taken to reduce the humidity of the first substrate when it is too high, thereby suppressing dendrite growth and ensuring the reliability of the first substrate.

[0010] In some embodiments, among the multiple solder balls, the orthographic projection of some solder balls onto the second surface lies within a third region of the second surface. Among these solder balls, at least one has a voltage difference greater than a second voltage difference threshold with respect to another solder ball. At least one humidity sensor embedded in the second dielectric layer has its orthographic projection onto the second surface within the third region. Since dendrites tend to grow in areas with relatively large voltage differences, embedding a humidity sensor in the second dielectric layer at a position corresponding to the third region allows for more accurate measurement of the humidity in the third region. This enables appropriate measures to be taken to reduce the humidity of the second substrate when humidity is excessive, thereby suppressing dendrite growth and ensuring the reliability of the second substrate.

[0011] In some embodiments, a filler adhesive layer is disposed between the first surface and the second surface. This filler adhesive layer can encapsulate solder balls and cover areas opposite to the first and second surfaces. The filler adhesive layer has void regions, and the orthographic projection of at least one humidity sensor embedded in the second dielectric layer onto the second surface at least partially coincides with the orthographic projection of the void regions onto the second surface. Dendrites tend to grow at locations on the second surface corresponding to the void regions. By embedding a humidity sensor in the second dielectric layer at the location corresponding to the void regions, the humidity of the area on the second surface corresponding to the void regions can be accurately measured. This allows for appropriate measures to be taken to reduce the humidity of the second substrate in cases of excessive humidity, thereby suppressing dendrite growth and ensuring the reliability of the second substrate.

[0012] In some embodiments, among the multiple solder balls, the orthographic projection of some solder balls onto the second surface lies within a fourth region of the second surface, where the welding stress is greater than a second stress threshold. At least one humidity sensor embedded in the second dielectric layer has its orthographic projection onto the second surface within this fourth region. Areas on the second surface with high welding stress are also prone to dendrite growth. By embedding a humidity sensor in the second dielectric layer at a position corresponding to the fourth region, the humidity of the fourth region can be measured more accurately. This allows for appropriate measures to be taken to reduce the humidity of the second substrate when it is too high, thereby suppressing dendrite growth and ensuring the reliability of the second substrate.

[0013] In some embodiments, the humidity sensor is a resistive humidity sensor. The humidity sensor includes a substrate, a humidity-sensitive material layer, a first electrode, and a second electrode. The humidity-sensitive material layer is disposed on the surface of the substrate, and the first and second electrodes are disposed on the side of the humidity-sensitive material layer facing away from the substrate. The first and second electrodes can each be comb-shaped electrodes, with the comb teeth of the first electrode and the comb teeth of the second electrode alternately arranged. When the humidity at the location of the humidity sensor changes, the humidity-sensitive material layer absorbs or releases moisture according to the change in humidity, causing a change in its dielectric constant, which in turn causes a change in the resistance value between the first and second electrodes.

[0014] In some implementations, the humidity sensor is a capacitive humidity sensor. The humidity sensor includes a substrate, a humidity-sensitive material layer, a first electrode, a second electrode, and an insulating layer, which are sequentially stacked on the substrate. When the humidity at the location of the humidity sensor changes, the humidity-sensitive material layer absorbs or releases moisture according to the change in humidity, causing a change in its dielectric constant, which in turn causes a change in the capacitance between the first and second electrodes.

[0015] In some implementations, the circuit board assembly may further include a shielding cover disposed on a first surface of the first substrate and enclosing the packaging module within it. The shielding cover is made of metal and can shield the packaging module from electromagnetic interference from other electronic devices disposed on the first substrate or other electronic devices inside the electronic device, thereby ensuring the operational reliability of the packaging module.

[0016] Secondly, this application also provides an electronic device, which includes a housing and a circuit board assembly as described in any of the embodiments of the first aspect, the circuit board assembly being disposed within the housing. This electronic device can acquire accurate internal humidity data using a humidity sensor embedded in the circuit board assembly, enabling it to provide users with early warnings in high humidity scenarios, reducing the risk of using the electronic device in high humidity environments, and improving the reliability of the electronic device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application;

[0018] Figure 2 A schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application;

[0019] Figure 3 A side sectional view of a circuit board assembly provided in an embodiment of this application;

[0020] Figure 4 A side sectional view of a partial structure of a circuit board assembly provided in an embodiment of this application;

[0021] Figure 5 Another side sectional view of a partial structure of the circuit board assembly provided in an embodiment of this application;

[0022] Figure 6 This is a schematic diagram of the structure of a humidity sensor provided in an embodiment of this application;

[0023] Figure 7 This is a schematic diagram of another humidity sensor provided in an embodiment of this application.

[0024] Figure label:

[0025] 1000 - Electronic device; 100 - Circuit board assembly; 100A - Main circuit board assembly; 100B - Secondary circuit board assembly; 100a - Processor;

[0026] 100b - Memory; 100c - Power management unit; 110 - First substrate; 110a - First surface; 110a1 - First region; 110a2 - Second region;

[0027] 110b - Third surface; 111 - First copper-clad substrate; 1111 - First dielectric layer; 1112 - First copper layer; 112 - First via; 113 - Second via;

[0028] 120 - Package module; 121 - Second substrate; 121a - Second surface; 121a1 - Third region; 121a2 - Fourth region; 121b - Fourth surface;

[0029] 1211-Second copper-clad substrate; 12111-Second dielectric layer; 12112-Second copper layer; 122-Chip; 123-Molded package; 130-Solder ball;

[0030] 140 - Filler adhesive layer; 141 - Void area; 150 - Shielding cover; 151 - Frame; 152 - Cover;

[0031] 160 / 160a / 160b / 160c / 160d / 160e / 160f - Humidity sensor; 161 / 161a / 161d - First connection terminal;

[0032] 162 / 162a / 162d - Second connection terminal; 163 - Substrate; 164 - Humidity-sensitive material layer; 165 - First electrode; 166 - Second electrode;

[0033] 167 - Insulation layer; 200 - Housing; 300 - Battery; 400 - Display screen; 410 - Display panel; 500 - Camera; 600 - Audio module;

[0034] 610 - Speaker; 620 - Microphone; 700 - Communication module; 710 - Mobile communication module; 720 - Wireless communication module. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0036] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0037] Figure 1 This is a schematic diagram of the structure of the electronic device 1000 provided in an embodiment of this application. (Reference) Figure 1 As shown, the electronic device 1000 provided in this application embodiment can be a mobile phone, tablet PC, personal computer, wearable device (such as a smartwatch, smart bracelet, etc.), augmented reality (AR) / virtual reality (VR) device, laptop computer, netbook, personal digital assistant (PDA), headset, and other various devices, which will not be listed here. The electronic device 1000 includes a circuit board assembly 100 and a housing 200. The circuit board assembly 100 is disposed within the housing 200 to provide protection for the circuit board assembly 100. Various electronic components and functional modules can be integrated in the circuit board assembly 100 to support the electronic device 1000 in realizing corresponding functions.

[0038] In some embodiments, the electronic device 1000 may include a plurality of circuit board assemblies 100, for example Figure 1The illustration shows an example of an electronic device 1000 comprising two circuit board assemblies 100. The two circuit board assemblies 100 are a main circuit board assembly 100A and a secondary circuit board assembly 100B, i.e., a motherboard and a secondary board, where the secondary board may also be referred to as a backplane or expansion board. The main circuit board assembly 100A is responsible for most of the system functions of the electronic device 1000, such as storage management, battery management, and communication transmission. The secondary circuit board assembly 100B is connected to the main circuit board assembly 100A and can provide the electronic device 1000 with additional storage space, interfaces, or other functions to improve the performance of the electronic device 1000.

[0039] Of course, in some other embodiments, the electronic device 1000 may not include the secondary circuit board assembly 100B, and the electronic device 1000 may perform various functions through the main circuit board assembly 100A.

[0040] Continue to refer to Figure 1 The electronic device 1000 also includes a battery 300, which is connected to the main circuit board assembly 100A, the secondary circuit board assembly 100B, and other electronic components (such as cameras, microphones, speakers, and various sensors) in the electronic device 1000 to provide power to these electrical components and ensure the normal operation of the electronic device 1000.

[0041] Figure 2 This is a schematic diagram of the hardware structure of the electronic device 1000 provided in an embodiment of this application. (Reference) Figure 2 As shown in the embodiments of this application, in addition to the circuit board assembly 100, the electronic device 1000 may also include a display screen 400, a camera 500, an audio module 600, a communication module 700, and a sensor module 800, etc., which are respectively connected to the circuit board assembly 100. The circuit board assembly 100 may include a processor 100a, a memory 100b, an analog circuit module, a mixed-signal module, on-chip programmable logic, and a power management unit (PMU) 100c, etc. Each device may be independently packaged in the circuit board assembly 100, or it may be packaged as a system on chip (SoC) and then assembled in the circuit board assembly 100. This application does not limit this.

[0042] In the circuit board assembly, processor 100a is the control center of the electronic device. Processor 100a can connect to various electronic components of electronic device 1000 via various interfaces and lines. By running or executing software programs and / or modules stored in memory 100b, and by calling data stored in memory 100b, processor 100a performs various functions of electronic device 1000 and processes data, thereby realizing various services based on electronic device 1000. Processor 100a may include one or more processing units, such as application processors (APs), modem processors, graphics processing units (GPUs), image signal processors (ISPs), controllers, video codecs, digital signal processors (DSPs), baseband processors, and / or neural network processing units (NPUs). Different processing units can be independent devices or integrated into one or more processors. Memory is used to store instructions and data. Memory 100b can store instructions or data that the processor has just used or that is being used repeatedly. If the processor 100a needs to use the instruction or data again, it can directly retrieve it from the memory 100b, avoiding repeated accesses and reducing the waiting time of the processor 100a, thus improving system efficiency. The PMU 100c can dynamically adjust the power supply, operating frequency, and voltage of devices such as the processor 100a and memory 100b by monitoring the power consumption requirements and battery status of the electronic device 1000, thereby optimizing the power efficiency of the electronic device 1000.

[0043] The display screen 400 can be used to display information input by the user or information provided to the user, as well as various menus of the electronic device. The display screen 400 may include a display panel 410. The display panel 410 may be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), etc.

[0044] Camera 500 is used to capture still images or videos. Camera 500 includes an optical lens and a photosensitive element. An object is projected onto the photosensitive element through the optical lens, generating an optical image. The photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the light signal into an electrical signal, which is then passed to an ISP (Internet Service Provider) for conversion into a digital image signal. The ISP outputs the digital image signal to a DSP (Digital Signal Processor) for processing. The DSP converts the digital image signal into image signals in standard RGB, YUV, or other formats.

[0045] The audio module 600 includes a speaker 610, a microphone 620, etc. The circuit board assembly 100 also includes an audio circuit, which can convert audio data into signals that the speaker 610 can recognize, and transmit the signals to the speaker 610, where the speaker 610 converts them into sound signals for output. The microphone 620 is used to collect external sound signals, convert the collected external sound signals into signals that the audio circuit can recognize, and send them to the audio circuit.

[0046] The communication module 700 may include a mobile communication module 710 and a wireless communication module 720. The mobile communication module 710 can provide wireless communication solutions, including 2G / 3G / 4G / 5G, for use on the electronic device 1000; the wireless communication module 720 can provide wireless communication solutions, including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies, for use on the electronic device 1000.

[0047] The sensor module 800 may include pressure sensors, gyroscope sensors, barometric pressure sensors, magnetic sensors, accelerometers, distance sensors, proximity sensors, fingerprint sensors, temperature sensors, touch sensors, ambient light sensors, bone conduction sensors, etc. Each sensor can send its detection signal to the processor 100a for processing and analysis, and the processor 100a will execute the corresponding function. The functions of various sensors will not be described in detail here.

[0048] Those skilled in the art will understand that Figure 2 The hardware structure of the electronic device shown does not constitute a limitation on the electronic device 1000. The electronic device 1000 provided in the embodiments of this application may include more or fewer components than shown, may combine two or more components, or may have different component configurations.

[0049] In this embodiment, the processor 100a, memory 100b, PMU 100c, and other devices are assembled in a packaged structure within the circuit board assembly 100. The circuit board assembly 100 and the aforementioned components can be installed in different locations according to the internal spatial layout of the electronic device 1000 and the functions they need to perform. Typically, electronic devices or components require a relatively dry environment to maintain normal operation. In cases of severe humidity inside the electronic device 1000, problems such as dendrite short-circuit failures related to electrochemical migration at the circuit board level and decreased interface bonding strength within the packaged structure may occur. During the overall reflow soldering assembly of the circuit board assembly 100, short circuits between adjacent solder joints are also prone to occur. Therefore, real-time monitoring of humidity data at humidity-sensitive locations within the electronic device 1000 is crucial for improving humidity-related failures of the electronic device 1000.

[0050] Currently, electronic devices 1000 typically acquire humidity data in two ways: one is through internet weather data, and the other is through humidity sensors mounted on the circuit board. However, humidity data acquired via the internet cannot characterize the internal humidity of the electronic device 1000. While surface-mount humidity sensors can detect internal humidity, they cannot reflect the humidity at high-risk failure locations within the circuit board assembly 100. Therefore, humidity data acquired using these two methods cannot be used to accurately analyze humidity-related failures of the circuit board assembly.

[0051] In view of this, embodiments of this application provide a circuit board assembly that can accurately measure humidity, thereby providing big data support for humidity-related reliability design and reducing the risk of circuit board assembly failure due to humidity issues. The circuit board assembly will be described in detail below with reference to specific embodiments.

[0052] Figure 3 This is a side sectional view of a circuit board assembly 100 provided in an embodiment of this application. (See reference...) Figure 3As shown in the embodiments of this application, the circuit board assembly 100 can be a motherboard or a sub-board of an electronic device, and this application does not limit this. The circuit board assembly 100 includes a first substrate 110 and a packaging module 120, with the packaging module 120 disposed on the first substrate 110. The packaging module 120 includes a second substrate 121 and a chip 122. One side surface of the second substrate 121 is used to mount the chip 122, and the other side surface of the second substrate 121 is fixed to the first substrate 110. The second substrate 121 can serve as a carrier for the chip 122, providing electrical connection, protection, support, heat dissipation, and other functions for the chip 122. Exemplarily, the chip 122 can be connected to the second substrate 121 by flip-chip bonding, wire bonding, or other methods.

[0053] In the packaging module 120, the chip 122 may include one or more chips such as a processor chip, a memory chip, or a power management chip. It is worth noting that when there are multiple chips 122, they can be packaged into a single unit using system-in-package (SIP) technology. Additionally, the packaging module 120 may also include a molding compound 123, which can be used to encapsulate at least a portion of the chip 122 and the second substrate 121 to secure the packaging module 120 as a single unit.

[0054] The packaging module 120 can be fixed to the first substrate 110 using a packaging method such as a ball grid array (BGA). The surface of the first substrate 110 facing the second substrate 121 is defined as the first surface 110a, and the surface of the second substrate 121 facing the first substrate 110 is defined as the second surface 121a. The second surface 121a and the first surface 110a are soldered together using multiple solder balls 130, thereby establishing an electrical connection between the second substrate 121 and the packaging module 120, enabling signal flow between the first substrate 110 and the packaging module 120.

[0055] Additionally, a filler adhesive layer 140 may be provided between the first surface 110a and the second surface 121a. The filler adhesive layer 140 can be formed by applying adhesive to the edge of the gap between the first surface 110a and the second surface 121a after the packaging module 120 is soldered onto the first substrate 110. This filler adhesive layer 140 can encapsulate the solder ball 130 and cover the second surface 121a, as well as the area opposite the first surface 110a. The filler adhesive layer 140 can improve the connection strength between the packaging module 120 and the first surface 110a, and also provide protection for the corresponding areas of the solder ball 130, the second surface 121a, and the first surface 110a, thereby improving the reliability of the circuit board assembly 100.

[0056] It should be understood that during the process of dispensing adhesive to form the filling adhesive layer 140, due to factors such as the fluidity and curing speed of the adhesive, the filling adhesive layer 140 may not completely fill the gap between the first surface 110a and the second surface 121a, resulting in a so-called void area 141. For example, when dispensing adhesive from the edge of the gap, the adhesive flows from the edge of the gap towards the center, making it easy for a void area 141 to appear in the center of the gap.

[0057] In this embodiment, the first substrate 110 can be a rigid circuit board, a flexible circuit board, or a rigid-flex circuit board. The first substrate 110 can be a single-layer circuit board or a multi-layer circuit board. In one embodiment, the first substrate 110 is a single-layer circuit board, formed from a single first copper-clad substrate 111. In another embodiment, the first substrate 110 is a multi-layer circuit board, formed by laminating multiple first copper-clad substrates 111, with adjacent first copper-clad substrates 111 bonded together using prepreg. The first copper-clad substrate 111 includes a first dielectric layer 1111 and a first copper layer 1112 disposed on at least one surface of the first dielectric layer 1111. The first copper layer 1112 can be formed into the desired circuit pattern through processes such as hole opening and etching.

[0058] As is readily understood, when the first substrate 110 is a multilayer board, the first substrate 110 includes a plurality of first dielectric layers 1111. The material of the first dielectric layer 1111 includes, but is not limited to, polytetrafluoroethylene (PTFE), or it may also be polyfluoroalkoxy (PFA), polyimide (PI), etc.

[0059] In this embodiment, the second substrate 121 can be a rigid circuit board, a flexible circuit board, or a rigid-flex circuit board. The second substrate 121 can be a single-layer circuit board or a multi-layer circuit board. In one embodiment, the second substrate 121 is a single-layer circuit board, and it can be formed from a single second copper-clad substrate 1211. In another embodiment, the second substrate 121 is a multi-layer circuit board, and it can be formed by laminating multiple second copper-clad substrates 1211, with adjacent second copper-clad substrates 1211 bonded together using prepreg. The second copper-clad substrate 1211 includes a second dielectric layer 12111 and a second copper layer 12112 disposed on at least one surface of the second dielectric layer 12111. The second copper layer 12112 can be formed into the desired circuit pattern through processes such as hole drilling and etching.

[0060] Similarly, when the second substrate 121 is a multilayer board, the second substrate 121 includes multiple second dielectric layers. The material of the second dielectric layer 12111 can also be PTFE, PFA, PI, etc.

[0061] In this embodiment, the circuit board assembly 100 may further include a shielding cover 150, which covers the first surface 110a of the first substrate 110 and encloses the packaging module 120. In other words, the packaging module 120 is located within the shielding space formed by the shielding cover 150 and the first substrate 110. The shielding cover 150 is made of metal and can shield the packaging module 120 from electromagnetic interference from other electronic devices disposed on the first substrate 110 or other electronic devices inside the electronic device, thereby ensuring the operational reliability of the packaging module 120.

[0062] In one embodiment, the shielding cover 150 is a split structure. The shielding cover 150 includes a frame 151 and a cover 152. The frame 151 is fixed to the first surface 110a and surrounds the periphery of the encapsulation module 120. The cover 152 covers the frame 151. Thus, the cover 152, the frame 151, and the first substrate 110 together form a shielding space to accommodate the encapsulation module 120. Specifically, the frame 151 can be fixed to the first surface 110a by welding, and the cover 152 can be fixed to the frame 151 by adhesive bonding. Since the cover 152 and the frame 151 are detachable, if a problem occurs with the encapsulation module 120, the encapsulation module 120 can be easily repaired by disassembling the cover 152 without damaging the connection between the frame 151 and the first substrate 110. Therefore, the circuit board assembly 100 using this type of shielding cover 150 has good maintainability.

[0063] In one embodiment, the shielding cover 150 is an integral structure. The shielding cover 150 is integrally disposed on the packaging module 120, and the shielding cover 150 and the first surface 110a can be fixed together by welding. The integral shielding cover 150 is relatively simple to assemble and position, which helps to simplify the overall assembly process of the circuit board assembly 100.

[0064] Please continue to refer to this. Figure 3As shown in the embodiments of this application, at least one of the first dielectric layer 1111 and the second dielectric layer 12111 is embedded with a humidity sensor 160. That is, the humidity sensor 160 is embedded inside the first substrate 110 and / or the second substrate 121. For example, the humidity sensor 160 may be embedded in the first dielectric layer 1111 and the second dielectric layer 12111 respectively; or, the humidity sensor 160 may be embedded in the first dielectric layer 1111 and not embedded in the second dielectric layer 12111; or, the humidity sensor 160 may be embedded in the second dielectric layer 12111 and not embedded in the first dielectric layer 1111.

[0065] Furthermore, when the first substrate 110 includes a plurality of first dielectric layers 1111, the humidity sensor 160 can be embedded in any one of the first dielectric layers 1111. Similarly, when the second substrate 121 includes a plurality of second dielectric layers 12111, the humidity sensor 160 can be embedded in any one of the second dielectric layers 12111.

[0066] In this embodiment, embedding the humidity sensor 160 in the first dielectric layer 1111 can be achieved during the fabrication of the first substrate 110. For example, during the fabrication of the first copper-clad substrate 111, the humidity sensor 160 is embedded in the molten first dielectric layer 1111, and then the humidity sensor 160 is fixed therein by curing the first dielectric layer 1111. Similarly, embedding the humidity sensor 160 in the second dielectric layer 12111 can be achieved during the fabrication of the second substrate 121. For example, during the fabrication of the second copper-clad substrate 1211, the humidity sensor 160 is embedded in the molten second dielectric layer 12111, and then the humidity sensor 160 is fixed therein by curing the second dielectric layer 12111.

[0067] Compared to surface-mounting the humidity sensor 160 onto the substrate surface, this embodiment embeds the humidity sensor 160 inside the first substrate 110 and / or the second substrate 121, enabling precise measurement of humidity data within the circuit board assembly 100. At the product design level, accurate measurement of humidity data within the circuit board assembly 100 facilitates monitoring under what humidity conditions reliability issues may arise, providing large-scale humidity-related data support for the reliability design of the circuit board assembly 100 and reducing the risk of failure due to humidity problems in subsequent designs. At the product application level, obtaining accurate humidity data within electronic devices allows them to provide early warnings in high-humidity environments, reducing the risk of using electronic devices in high-humidity conditions and improving their reliability.

[0068] In addition, the built-in humidity sensor 160 of the electronic device can provide users with temperature and humidity information of their location, enabling the device to function as a personal real-time weather station. Based on this function, the electronic device can achieve a variety of applications. For example, it can record the user's exercise performance under different weather conditions and remind the user to adjust their training and water intake accordingly; remind the user to adjust their skin care plan in dry or humid weather conditions; support users to control the electronic device by blowing air (in scenarios where disabled people take photos); and help farmers more easily understand the precise local climate changes, etc.

[0069] Figure 4 This is a side sectional view of a partial structure of the circuit board assembly 100 provided in an embodiment of this application. Figure 4 An example is shown where a humidity sensor 160 is embedded in a first substrate 110. One or more humidity sensors 160 may be embedded in the first substrate 110, for example... Figure 4 The illustration shows one scenario in which three humidity sensors 160 are embedded in the first substrate 110. The three humidity sensors 160 can be embedded in the same first dielectric layer 1111 of the first substrate 110, or they can be embedded in different first dielectric layers 1111 of the first substrate 110. The specific design can be made according to actual needs, and this application does not impose any restrictions on this.

[0070] Through-holes are respectively provided at the positions of the two connection terminals of the humidity sensor 160 in the first substrate 110. These through-holes allow the connection terminals of the humidity sensor 160 to be connected to the surface of the first substrate 110. The surface of the first substrate 110 opposite to the first surface 110a is defined as the third surface 110b. When both the first surface 110a and the third surface 110b are the first copper layer 1112, the through-holes can connect to either the first surface 110a or the third surface 110b; this application does not limit this connection. For example… Figure 4 As shown, the first via 112 can connect the first connection terminal 161a of the humidity sensor 160a to one lead terminal of the first surface 110a, and the second via 113 can connect the second connection terminal 162a of the humidity sensor 160a to the other lead terminal of the first surface 110a. In this way, the lead terminal can be connected to the corresponding solder ball 130 through the trace of the first surface 110a, and further connected to the package module 120 through the solder ball 130, so that the chip 122 (such as a processor chip) in the package module 120 can obtain the humidity information detected by the humidity sensor 160a.

[0071] Please refer to the above. Figure 3 and Figure 4As shown, among the plurality of solder balls 130 connecting the first surface 110a and the second surface 121a, the orthographic projection of some solder balls 130 onto the first surface 110a lies within a first region 110a1 of the first surface 110a. Among these solder balls 130 whose orthographic projection lies within the first region 110a1, the voltage difference between at least one solder ball 130 and another solder ball 130 is greater than a voltage difference threshold. The first voltage difference threshold can be determined experimentally or empirically, and will not be elaborated upon here.

[0072] In this embodiment, at least one humidity sensor 160 embedded in the first dielectric layer 1111 has its orthographic projection on the first surface 110a located within the first region 110a1, for example... Figure 4 The humidity sensor 160a is embedded in the first dielectric layer 1111. That is, the humidity sensor 160 is positioned opposite to the area with a relatively large voltage difference.

[0073] Dendrites tend to grow more easily on the first surface 110a of the first substrate 110 in areas with relatively large voltage differences. As mentioned above, humidity is a significant factor promoting dendrite growth. If areas with relatively large voltage differences also have high humidity, dendrite growth is more likely to occur. Therefore, monitoring the humidity in areas with relatively large voltage differences is crucial for controlling dendrite growth. In this embodiment, the first region 110a1 of the first surface 110a is connected to the solder ball 130 with a relatively large voltage difference. Therefore, the corresponding position of the first region 110a1 also has a large voltage difference. By embedding a humidity sensor 160a in the first dielectric layer 1111 at a position corresponding to the first region 110a1, the humidity of the first region 110a1 can be measured more accurately using the humidity sensor 160a. This allows for appropriate measures to be taken to reduce the humidity of the first substrate 110 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the first substrate 110.

[0074] In this embodiment, measures to reduce the humidity of the first substrate 110 may include at least one of the following: using a first substrate 110 made of a material with low moisture absorption rate; using an adhesive with low moisture absorption rate to form a filling adhesive layer 140.

[0075] Please continue to refer to this. Figure 3 and Figure 4 In some embodiments, when the filler layer 140 has void regions 141, the orthographic projection of at least one humidity sensor 160 embedded in the first dielectric layer 1111 onto the first surface 110a at least partially coincides with the orthographic projection of the void region 141 onto the first surface 110a, for example... Figure 4The humidity sensor 160b is shown in the figure. The area on the first surface 110a corresponding to the void region 141 of the filler layer 140 is also a location prone to dendrite growth; therefore, monitoring the humidity in this area is crucial for controlling dendrite growth. In this embodiment, by embedding the humidity sensor 160b in the first dielectric layer 1111 at the position corresponding to the void region 141, the humidity sensor 160b can accurately measure the humidity of the area on the first surface 110a corresponding to the void region 141. This allows for appropriate measures to be taken to reduce the humidity of the first substrate 110 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the first substrate 110. The measures for reducing the humidity of the first substrate 110 can be referred to the description in the previous embodiments and will not be repeated here.

[0076] In other embodiments, the embedding position of the humidity sensor 160 in the first dielectric layer 1111 can also be determined based on the welding stress of the first substrate 110. For example, among the plurality of solder balls 130 connecting the first surface 110a and the second surface 121a, the orthographic projection of some solder balls 130 on the first surface 110a is located within a second region 110a2 of the first surface 110a, and the welding stress in the second region 110a2 is greater than a stress threshold. In this case, at least one humidity sensor 160 embedded in the first dielectric layer 1111 has its orthographic projection on the first surface 110a located within the second region 110a2, for example... Figure 4 The humidity sensor 160c is embedded in the first dielectric layer 1111. That is, the humidity sensor 160c is positioned opposite to the area with relatively high welding stress.

[0077] In specific implementation, the welding stress in each region of the first surface 110a can be obtained through simulation during the design phase based on the arrangement of the solder balls 130, and the first stress threshold can be determined based on experiments or experience. As those skilled in the art know, areas with high welding stress on the first surface 110a are also prone to dendrite growth; therefore, monitoring the humidity in this area is crucial for controlling dendrite growth. In this embodiment, by embedding a humidity sensor 160c in the first dielectric layer 1111 at a position corresponding to the second region 110a2, the humidity of the second region 110a2 can be measured more accurately using the humidity sensor 160c. This allows for appropriate measures to be taken to reduce the humidity of the first substrate 110 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the first substrate 110. The measures for reducing the humidity of the first substrate 110 can be referred to the description in the preceding embodiments, and will not be repeated here.

[0078] Figure 5 This is another side sectional view of a partial structure of the circuit board assembly 100 provided in an embodiment of this application. Figure 5The diagram illustrates an example of a humidity sensor 160 embedded in a second substrate 121. One or more humidity sensors 160 may be embedded in the second substrate 121, for example... Figure 5 The illustration shows one scenario in which three humidity sensors 160 are embedded in the second substrate 121. The three sensors can be embedded in the same second dielectric layer 12111 of the second substrate 121, or they can be embedded in different second dielectric layers 12111 of the second substrate 121. The specific design can be made according to actual needs, and this application does not impose any restrictions on this.

[0079] Through-holes are provided at the positions of the two connection terminals of the humidity sensor 160 in the second substrate 121. These through-holes allow the connection terminals of the humidity sensor 160 to be connected to the surface of the second substrate 121. The surface of the second substrate 121 opposite to the second surface 121a is defined as the fourth surface 121b. When both the second surface 121a and the fourth surface 121b are the second copper layer 12112, the through-holes can connect to either the second surface 121a or the fourth surface 121b; this application does not limit this connection. Figure 5 As shown, the third via 1212 can connect the first connection terminal 161d of the humidity sensor 160d to one lead terminal of the fourth surface 121b, and the fourth via 1213 can connect the second connection terminal 162d of the humidity sensor 160d to another lead terminal of the fourth surface 121b. In this way, the lead terminal can be connected to the chip 122 (such as a processor chip) using the traces on the fourth surface 121b, so that the chip 122 can obtain the humidity information detected by the humidity sensor 160d.

[0080] Please refer to the above. Figure 3 and Figure 5 As shown, among the plurality of solder balls 130 connecting the first surface 110a and the second surface 121a, the orthographic projection of some solder balls 130 onto the second surface 121a lies within a third region 121a1 of the second surface 121a. Among these solder balls 130 whose orthographic projection lies within the third region 121a1, at least one solder ball 130 has a voltage difference greater than a voltage difference threshold with another solder ball 130. The second voltage difference threshold can be determined experimentally or empirically, and will not be elaborated upon here.

[0081] In this embodiment, at least one humidity sensor 160 embedded in the second dielectric layer 12111 has its orthographic projection on the second surface 121a located within the third region 121a1, for example... Figure 5 The humidity sensor 160d is embedded in the second dielectric layer 12111. That is, the humidity sensor 160d is positioned opposite to the area with a relatively large voltage difference.

[0082] Dendrites tend to grow more easily on the second surface 121a of the second substrate 121 in areas with relatively large voltage differences. Therefore, monitoring the humidity in these areas is crucial for controlling dendrite growth on the second surface 121a. In this embodiment, the third region 121a1 of the second surface 121a is connected to the solder ball 130 with a relatively large voltage difference. Therefore, the corresponding position in the third region 121a1 also has a large voltage difference. By embedding a humidity sensor 160d in the second dielectric layer 12111 at a position corresponding to the third region 121a1, the humidity of the third region 121a1 can be measured more accurately. This allows for appropriate measures to be taken to reduce the humidity of the second substrate 121 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the second substrate 121.

[0083] In this embodiment, measures for reducing the humidity of the second substrate 121 may include at least one of the following: using a second substrate 121 made of a material with low moisture absorption; using an adhesive with low moisture absorption to form a filling adhesive layer 140; and reducing the relative humidity of the chip 122 before assembling the chip 122 onto the second substrate 121.

[0084] Please continue to refer to this. Figure 3 and Figure 5 In some embodiments, when the filler layer 140 has void regions 141, the orthographic projection of at least one humidity sensor 160 embedded in the second dielectric layer 12111 onto the second surface 121a can be located within the orthographic projection of the void region 141 onto the second surface 121a, for example... Figure 5 The humidity sensor 160e is shown in the figure. The area on the second surface 121a corresponding to the void region 141 of the filler layer 140 is also a location prone to dendrite growth; therefore, monitoring the humidity in this area is crucial for controlling dendrite growth. In this embodiment, by embedding the humidity sensor 160e in the second dielectric layer 12111 at the position corresponding to the void region 141, the humidity sensor 160e can accurately measure the humidity of the area on the second surface 121a corresponding to the void region 141. This allows for appropriate measures to be taken to reduce the humidity of the second substrate 121 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the second substrate 121. The measures for reducing the humidity of the second substrate 121 can be referred to the description in the previous embodiments, and will not be repeated here.

[0085] In other embodiments, the embedding position of the humidity sensor 160 in the second dielectric layer 12111 can also be determined based on the welding stress of the second substrate 121. For example, among the plurality of solder balls 130 connecting the first surface 110a and the second surface 121a, the orthographic projection of some solder balls 130 on the second surface 121a is located within a fourth region 121a2 of the second surface 121a, and the welding stress in the fourth region 121a2 is greater than a stress threshold. In this case, at least one humidity sensor 160 embedded in the second dielectric layer 12111 has its orthographic projection on the second surface 121a located within the fourth region 121a2, for example... Figure 5 The humidity sensor 160f is embedded in the second dielectric layer 12111. In other words, the humidity sensor 160f is positioned opposite to the area with relatively high welding stress.

[0086] In the specific implementation, the welding stress in each region of the second surface 121a can be obtained through simulation during the design phase based on the arrangement of the solder balls 130, and the second stress threshold can be determined based on experiments or experience. Since areas with high welding stress on the second surface 121a are also prone to dendrite growth, monitoring the humidity in this area is also important for controlling dendrite growth. In this embodiment, by embedding a humidity sensor 160f in the second dielectric layer 12111 at a position corresponding to the fourth region 121a2, the humidity of the fourth region 121a2 can be measured more accurately using the humidity sensor 160f. This allows for appropriate measures to be taken to reduce the humidity of the second substrate 121 when the humidity is too high, thereby suppressing dendrite growth and ensuring the reliability of the second substrate 121. The measures to reduce the humidity of the second substrate 121 can be referred to the description in the previous embodiments, and will not be repeated here.

[0087] In this application embodiment, the specific type of humidity sensor 160 is not limited and can be selected according to actual needs. The following are examples illustrating the structure of two humidity sensors 160 and their application in the circuit board assembly 100.

[0088] Figure 6 This is a schematic diagram of the structure of a humidity sensor 160 provided in an embodiment of this application. (Reference) Figure 6As shown in this embodiment, the humidity sensor 160 is a resistive humidity sensor 160. The humidity sensor 160 includes a substrate 163, a humidity-sensitive material layer 164, a first electrode 165, and a second electrode 166. The substrate 163 is made of an insulating material; exemplarily, the substrate 163 can be made of alumina. The humidity-sensitive material layer 164 is disposed on the surface of the substrate 163, and the resistance of the humidity-sensitive material layer 164 can change with humidity. Exemplarily, the material of the humidity-sensitive material layer 164 can be, but is not limited to, polyimide. The first electrode 165 and the second electrode 166 are disposed on the side of the humidity-sensitive material layer 164 facing away from the substrate. The first electrode 165 and the second electrode 166 can each be a comb-shaped electrode, with the comb teeth of the first electrode 165 and the comb teeth of the second electrode 166 interleaved.

[0089] Combination Figure 4 As shown, taking the humidity sensor 160 in the first substrate 110 as an example of the aforementioned resistive humidity sensor 160, the humidity sensor 160 is embedded in the first dielectric layer 1111. One end of the first electrode 165 can serve as the first connection terminal 161 of the humidity sensor 160, and is connected to one lead terminal of the first surface 110a through a via. One end of the second electrode 166 can serve as the second connection terminal 162 of the humidity sensor 160, and is connected to the other lead terminal of the first surface 110a through a via. When the humidity of the first surface 110a changes, the humidity at the location of the humidity sensor 160 will also change accordingly. In this way, the humidity-sensitive material layer 164 will absorb or release moisture according to the change in humidity, causing its dielectric constant to change, which in turn causes the resistance value between the first electrode 165 and the second electrode 166 to change. After the chip 122 obtains the resistance value between the first electrode 165 and the second electrode 166, it can determine the humidity information at the location of the humidity sensor 160 according to the correspondence between the resistance value and the humidity.

[0090] Of course, in some embodiments, the humidity sensor 160 may also have its own integrated chip. In this case, one end of the first electrode 165 and one end of the second electrode 166 are respectively connected to the two input pins of the sensor chip. The sensor chip calculates the humidity information based on the resistance value between the first electrode 165 and the second electrode 166, and then transmits the humidity information to the chip 122 in the packaging module 120 through the two output pins. It is easy to understand that in this case, the two output pins of the sensor chip are the first connection terminal and the second connection terminal of the humidity sensor 160.

[0091] Figure 7 This is a schematic diagram of another humidity sensor 160 provided in an embodiment of this application. (See reference...) Figure 7As shown in this embodiment, the humidity sensor 160 is a capacitive humidity sensor. The humidity sensor 160 includes a substrate 163, a humidity-sensitive material layer 164, a first electrode 165, a second electrode 166, and an insulating layer 167. The substrate 163 can be made of silicon, and the insulating layer 167, the first electrode 165, the humidity-sensitive material layer 164, and the second electrode 166 are sequentially stacked on the substrate 163. The resistance of the humidity-sensitive material layer 164 can change with humidity. Exemplarily, the material of the humidity-sensitive material layer 164 can be, but is not limited to, polyimide. The first electrode 165 and the second electrode 166 each include an electrode port for external connection.

[0092] Combination Figure 5 As shown, taking the humidity sensor 160 in the second substrate 121 as an example (e.g., the capacitive humidity sensor 160), the humidity sensor 160 is embedded in the second dielectric layer 12111. The electrode port of the first electrode 165 can serve as the first connection terminal of the humidity sensor 160 and is connected to one lead terminal of the fourth surface 121b through a via. The electrode port of the second electrode can serve as the second connection terminal of the humidity sensor 160 and is connected to another lead terminal of the fourth surface 121b through a via. When the humidity of the second surface 121a changes, the humidity at the location of the humidity sensor 160 will also change accordingly. Thus, the humidity-sensitive material layer 164 will absorb or release moisture according to the change in humidity, causing a change in its dielectric constant, which in turn causes a change in the capacitance between the first electrode 165 and the second electrode 166. After obtaining the capacitance between the first electrode 165 and the second electrode 166, the chip 122 can determine the humidity information at the location of the humidity sensor 160 based on the correspondence between capacitance and humidity.

[0093] Similarly, in some embodiments, the humidity sensor 160 may also have its own integrated chip. In this case, the electrode ports of the first electrode 165 and the second electrode 166 are respectively connected to the two input pins of the sensor chip. The sensor chip calculates the humidity information based on the capacitance between the first electrode 165 and the second electrode 166, and then transmits the humidity information to the chip 122 through its two output pins. It is easy to understand that in this case, the two output pins of the sensor chip are the first and second connection terminals of the humidity sensor 160.

[0094] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A circuit board assembly, characterized in that, The device includes a first substrate and a packaging module, wherein the packaging module is disposed on the first substrate, and the packaging module includes a second substrate and a chip disposed on the second substrate; the first substrate includes a first dielectric layer, and the second substrate includes a second dielectric layer. A humidity sensor is embedded in at least one of the first and second dielectric layers.

2. The circuit board assembly as claimed in claim 1, characterized in that, The first substrate includes a first surface, and the second substrate includes a second surface, wherein the second surface is soldered to the first surface by a plurality of solder balls; Among the plurality of solder balls, the orthographic projection of some of the solder balls on the first surface is located within a first region of the first surface, and among the solder balls whose orthographic projection is located within the first region, the voltage difference between at least one solder ball and another solder ball is greater than a first voltage difference threshold. At least one of the humidity sensors embedded in the first medium layer has its orthographic projection on the first surface located within the first region.

3. The circuit board assembly as described in claim 2, characterized in that, A filler adhesive layer is disposed between the first surface and the second surface, the filler adhesive layer being used to encapsulate the solder ball, and the filler adhesive layer having void areas; The orthographic projection of at least one of the humidity sensors embedded in the first dielectric layer onto the first surface coincides at least partially with the orthographic projection of the void region onto the first surface.

4. The circuit board assembly as described in claim 2 or 3, characterized in that, Among the plurality of solder balls, the orthographic projection of some of the solder balls onto the first surface is located in a second region of the first surface, and the welding stress in the second region is greater than a first stress threshold. At least one of the humidity sensors embedded in the first dielectric layer has its orthographic projection on the first surface located in the second region.

5. The circuit board assembly as described in any one of claims 2-4, characterized in that, Of the plurality of solder balls, the orthographic projection of some of the solder balls onto the second surface lies within a third region of the second surface, and among the solder balls whose orthographic projection lies within the third region, the voltage difference between at least one solder ball and another solder ball is greater than a second voltage difference threshold. At least one of the humidity sensors embedded in the second dielectric layer has its orthographic projection on the second surface located within the third region.

6. The circuit board assembly as described in any one of claims 2-5, characterized in that, A filler adhesive layer is disposed between the first surface and the second surface, the filler adhesive layer being used to include the solder ball, and the filler adhesive layer having void areas; The orthographic projection of at least one of the humidity sensors embedded in the second dielectric layer on the second surface at least partially coincides with the orthographic projection of the void region on the second surface.

7. The circuit board assembly as described in any one of claims 2-6, characterized in that, Of the plurality of solder balls, the orthographic projection of some of the solder balls onto the second surface lies within a fourth region of the second surface, and the welding stress in the fourth region is greater than or equal to a second stress threshold. The orthographic projection of the second surface of at least one humidity sensor embedded in the second dielectric layer is located within the fourth region.

8. The circuit board assembly as described in any one of claims 1-7, characterized in that, The humidity sensor is a resistive humidity sensor.

9. The circuit board assembly as described in any one of claims 1-7, characterized in that, The humidity sensor is a capacitive humidity sensor.

10. An electronic device, characterized in that, It includes a housing and a circuit board assembly as described in any one of claims 1-9, the circuit board assembly being disposed within the housing.

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