Radio frequency module, communication equipment and preparation method thereof

Abstract

The invention relates to the technical field of radio frequency communication, and discloses a radio frequency module, communication equipment and a preparation method thereof, the radio frequency module comprises a radio frequency chip, a first device is arranged on a first surface of the radio frequency chip; a second surface of the radio frequency substrate is provided with a second device; the first surface and the second surface are oppositely arranged, the first device is in bonding connection with the radio frequency substrate, and the first device is electrically connected with the second device; the radio frequency chip and the radio frequency substrate are made of different substrate materials, the first device is an active device, and the second device is a passive device. The radio frequency communication circuit has the beneficial effects that the active device and the passive device required by the communication circuit are respectively processed on the radio frequency chip and the radio frequency substrate, and the complete radio frequency communication circuit is formed based on the bonding connection of the active device and the radio frequency substrate, so that the advantages of different substrate materials in the processing process are fully utilized; the process complexity and the processing cost of the radio frequency chip are reduced, and the process flow of the radio frequency module is effectively optimized.

Description

Technical Field

[0001] This application relates to the field of radio frequency communication technology, and in particular to a radio frequency module, communication equipment and its manufacturing method. Background Technology

[0002] With the development and popularization of mobile communication technology, hardware such as RF front-end chips and RF modules are gradually evolving towards miniaturization. However, with increasing communication requirements, hardware devices typically need to integrate multiple communication components to achieve various communication functions and meet practical communication needs. In related technologies, RF modules include RF front-end chips and RF substrates. The RF front-end chip usually has fully functional communication circuits fabricated on it, including active and passive components. However, due to the increasing number of active and passive components, the manufacturing process of the RF front-end chip becomes excessively complex when using traditional techniques, leading to increased manufacturing costs.

[0003] Therefore, there is an urgent need to propose a technical solution that can optimize the process flow of the RF module while ensuring that the communication capability of the RF module is not affected. Summary of the Invention

[0004] This application provides a radio frequency (RF) module, a communication device, and a method for fabricating the same. Active and passive devices required for the communication circuit are fabricated on an RF chip and an RF substrate, respectively, to form a complete RF communication circuit based on the bonding connection between the active devices and the RF substrate. This fully utilizes the advantages of different substrate materials in the processing, reduces the process complexity and processing cost of the RF chip, and effectively optimizes the process flow of the RF module.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a radio frequency module, including: A radio frequency chip, wherein a first device is disposed on a first surface of the radio frequency chip; A radio frequency substrate, wherein a second device is disposed on the second surface of the radio frequency substrate; The first surface and the second surface are disposed opposite to each other, the first device is bonded to the radio frequency substrate, and the first device and the second device are electrically connected. The radio frequency chip and the radio frequency substrate are made of different substrate materials. The first device is an active device and the second device is a passive device.

[0006] The RF module proposed in this application uses RF chips and RF substrates with different substrate materials. An active device, serving as a first device, is provided on the first surface of the RF chip, and a passive device, serving as a second device, is provided on the second surface of the RF substrate, with the first and second surfaces positioned opposite each other. Through bonding between the first device and the RF substrate, the first and second devices are electrically connected to form a complete RF communication circuit, thereby enabling communication functionality. Compared with related technologies, this application splits the communication circuit in conventional RF chips, retaining the active devices on the RF chip and transferring the passive devices from the RF chip to the RF substrate. This reduces the number of devices on the RF chip, effectively reducing the process complexity of the RF chip and optimizing the RF module's process flow by leveraging the advantages of the RF substrate over the RF chip in substrate material, while ensuring that communication functionality is not affected. Furthermore, utilizing the advantages of the RF substrate over the RF chip in substrate material also reduces the processing cost of the RF module, which is beneficial for the large-scale production and promotion of the RF module.

[0007] Optionally, the substrate of the radio frequency chip is any one of a compound substrate, a silicon substrate, and an insulating silicon substrate.

[0008] Optionally, the substrate of the radio frequency substrate is a glass substrate.

[0009] Optionally, the first device includes a transistor, on which bonding bumps are grown, and the transistor is bonded to the radio frequency substrate through the bonding bumps.

[0010] Optionally, the sum of the height of the bonding protrusion and the height of the first device is greater than the height of the second device.

[0011] Optionally, the second device includes two or more passive devices.

[0012] Optionally, the second surface is provided with metal wiring, and the first device is electrically connected to the second device through the metal wiring.

[0013] Optionally, there may be multiple first devices, and the metal wiring and the second devices form a functional circuit on the second surface, with the first devices being electrically connected to each other through the functional circuit.

[0014] Secondly, embodiments of this application provide a communication device, which includes the radio frequency module described in any of the above embodiments.

[0015] Thirdly, embodiments of this application provide a method for fabricating a radio frequency module, the method comprising: A radio frequency (RF) chip and an RF substrate are provided; wherein the RF chip includes a first surface and the RF substrate includes a second surface; A first device is formed on the first surface by photolithography and etching using a first photomask; wherein the first device includes an electrode metal layer for electrical connection; Using a second photomask, a second device and metal wiring are formed on the second surface by photolithography and etching; Bonding protrusions are grown on the electrode metal layer; The first surface is placed relative to the second surface, and the first device is bonded to the RF substrate through the bonding bumps to obtain the RF module; wherein the first device and the second device are electrically connected through the metal wiring and the bonding bumps. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1a This is a schematic diagram of the device layout of an RF module in related technologies; Figure 1b This is a schematic diagram of the device layout of the radio frequency module provided in the embodiments of this application; Figure 2 This is a cross-sectional schematic diagram of the radio frequency module provided in the embodiments of this application; Figure 3 This is a cross-sectional schematic diagram of the radio frequency module in the embodiments of this application; Figure 4 A flowchart illustrating the fabrication method of the radio frequency module provided in this application embodiment; Figure 5a This is a schematic diagram of the fabrication process of the radio frequency module in the embodiments of this application; Figure 5b This is a schematic diagram of the fabrication process of the radio frequency module in the embodiments of this application; Figure 5c This is a schematic diagram of the fabrication process of the radio frequency module in the embodiments of this application; Figure 6a This is a schematic diagram of the fabrication process of the radio frequency module in the embodiments of this application; Figure 6b This is a schematic diagram of the fabrication process of the radio frequency module in the embodiments of this application.

[0018] The reference numerals in the accompanying drawings are as follows: 100. Radio frequency chip, 110. First device, 120. Bonding bump, 200. Radio frequency substrate, 210. Second device, 220. Metal wiring. Detailed Implementation

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0021] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0022] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0023] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0024] With the development and popularization of mobile communication technology, hardware such as RF front-end chips and RF modules are gradually evolving towards miniaturization. However, as communication requirements increase, hardware devices typically need to integrate multiple communication components to implement various communication functions and meet practical communication needs. (Refer to...) Figure 1a As shown, in related technologies, an RF module includes an RF front-end chip and an RF substrate. The RF front-end chip typically has a fully functional communication circuit, including electrically connected first and second devices. This communication circuit is electrically connected to a matching circuit on the RF substrate to form a complete RF module. However, due to the increased number of first and second devices, when using conventional techniques to process the RF module, these devices not only occupy a large portion of the RF front-end chip's area but also increase the chip's manufacturing complexity, leading to higher processing costs. Furthermore, conventional processes typically use resin or similar materials for the RF substrate. Resin substrates generate high signal loss when transmitting high-frequency signals, affecting the RF module's communication function. Designing a dedicated high-frequency signal substrate for this purpose would increase processing costs. Therefore, there is an urgent need for a technical solution that optimizes the RF module's process flow while ensuring the module's communication capabilities are not compromised.

[0025] Based on the above problems, this application provides a radio frequency module, a communication device and a method for manufacturing the same. The radio frequency module includes: a radio frequency chip, a first device disposed on a first surface of the radio frequency chip; a radio frequency substrate, a second device disposed on a second surface of the radio frequency substrate; the first surface and the second surface are disposed opposite to each other, the first device is bonded to the radio frequency substrate, and the first device and the second device are electrically connected; the radio frequency chip and the radio frequency substrate are respectively made of different substrate materials, the first device is an active device and the second device is a passive device.

[0026] The radio frequency module provided in this application uses radio frequency chips and radio frequency substrates with different substrate materials. An active device as a first device is provided on the first surface of the radio frequency chip, and a passive device as a second device is provided on the second surface of the radio frequency substrate, wherein the first surface and the second surface are arranged opposite to each other. Through the bonding connection between the first device and the radio frequency substrate, the first device and the second device can be electrically connected. Through the cooperative work between the first device and the second device, a complete radio frequency communication circuit is formed, thereby realizing the communication function.

[0027] Compared with related technologies, this application splits the communication circuit in a conventional RF chip, retains the active devices on the RF chip, and transfers the passive devices on the RF chip to the RF substrate, thereby reducing the number of devices on the RF chip. Thus, while ensuring that the communication function is not affected, the advantages of the RF substrate over the RF chip in substrate material are utilized to effectively reduce the process complexity of the RF chip and optimize the process flow of the RF module.

[0028] Furthermore, leveraging the advantages of RF substrates over RF chips in substrate materials can reduce the processing costs required for RF modules, which is beneficial for the large-scale production and promotion of RF modules.

[0029] The RF module provided in this manual can be used in communication devices with communication functions. These communication devices may include laptops, desktop computers, smartphones, smart wearable devices (virtual reality glasses, smartwatches, etc.), and tablets. It is understood that the RF module provided in this manual, after adaptive modifications, can also be used in other fields outside the communication field, such as radar sensing, positioning and navigation, or precision fields.

[0030] Embodiments of the invention are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures) of the invention, thus allowing for variations in the illustrated shape due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of the invention.

[0031] This embodiment provides a radio frequency module that can be used in the aforementioned communication device. (Refer to...) Figure 1b As shown, the radio frequency module includes: a first device disposed on a first surface of a radio frequency chip; a second device disposed on a second surface of a radio frequency substrate; the first surface and the second surface are disposed opposite to each other, the first device is bonded to the radio frequency substrate, and the first device and the second device are electrically connected; the radio frequency chip and the radio frequency substrate are respectively made of different substrate materials, the first device is an active device, and the second device is a passive device.

[0032] Specifically, the RF module includes an RF chip 100 and an RF substrate 200. The number of RF chips 100 can be one or more, and all RF chips 100 are integrated on the surface of the RF substrate 200. The electrical connection between the two forms an RF module with complete communication circuitry. The substrate of the RF chip 100 uses a first substrate material suitable for implementing a first device 110, ensuring that the first device 110 exhibits excellent RF signal processing performance across multiple frequency ranges. The substrate of the RF substrate 200 uses a second substrate material suitable for implementing a second device 210, ensuring that the second device 210 can function normally on the surface of the RF substrate 200 and cooperates with the first device 110 on the RF chip 100 to realize the communication function of the RF module. The first substrate material and the second substrate material are different. The difference between the two may be that they have different effects on device performance, making the types of devices that the two substrate materials are suitable for. Alternatively, the two substrate materials may have different material costs, making it impossible for the more expensive substrate material to be used on a large scale. Or, the two substrate materials may have different processing technologies, making it impossible for the more complex substrate material to be used on a large scale.

[0033] The radio frequency chip 100 has two opposing surfaces, with a first device 110 disposed on the first surface. The first device 110 can be formed on the first surface using semiconductor processing technology, or it can be pre-manufactured and then mounted on the first surface using surface mounting technology. The first device 110 is an active device, and its quantity can be one or more. Its type can be a device that must be implemented using a first substrate material, or a device whose implementation effect on the first substrate material is better than that on other substrate materials, including but not limited to transistors or diodes, for use in forming driver amplifiers or power amplifiers, etc. It should be noted that... Figure 1b The connection method between the first device 110 and the second device 210 is only for illustration. The surface of the RF chip 100 has only the first device 110. The connection between the first devices 110 and the connection between the first device 110 and the second device 210 can be achieved through the surface of the RF substrate 200, thereby avoiding the processing of connection circuits on the surface of the RF chip 100, effectively reducing the surface area of ​​the RF chip 100 and reducing the material cost of the RF chip 100.

[0034] The RF substrate 200 has two opposing surfaces, with a second device 210 disposed on the second surface. The second device 210 can be formed on the second surface using semiconductor processing technology, or it can be pre-manufactured and then mounted on the second surface using surface mounting technology. The second device 210 is a passive device, and its number can be one or more. Its types can include, but are not limited to, capacitors, inductors, matching networks, impedance transformation networks, filter networks, and couplers. The second devices 210 can be interconnected on the second surface or used to electrically connect with the first device 110, thereby combining with the first device 110 to ensure that RF signals can be transmitted with minimal signal loss and improve the signal quality of the RF module.

[0035] In some embodiments, the first substrate material can also be used to implement the second device 210. When the first substrate material is gallium arsenide and the second substrate material is glass, the reason for implementing the second device 210 on the RF substrate 200 is explained exemplarily: the second device 210 typically occupies a large area. If the second device 210 is implemented on the RF chip 100, it will occupy most of the area of ​​the RF chip 100, preventing the area of ​​the RF chip 100 from being reduced. Furthermore, the material cost of gallium arsenide is much higher than that of glass; the larger the area of ​​the RF chip 100, the higher the material cost required to produce the RF module. Therefore, if the second device 210 is transferred to the surface of the RF substrate 200, the second device 210 can be implemented using glass, which has a lower material cost, instead of gallium arsenide. This effectively reduces the surface area of ​​the RF chip 100 and lowers the material cost of the RF chip 100 while ensuring that the performance of the second device 210 is not affected.

[0036] Furthermore, device fabrication on gallium arsenide substrates typically employs a multi-step conventional process using photomasks, including active device fabrication, passive device integration, and interconnection between active and passive devices. Each step requires a separate photomask, necessitating photomask design and production for each step. Moreover, conventional processes impose high requirements on the linewidth accuracy of the photomasks, all of which contribute to increased processing costs. While device fabrication on glass substrates still requires photomasks, the required linewidth accuracy is significantly lower compared to conventional processes, resulting in a substantial reduction in processing costs. Therefore, in this embodiment, only some steps of the conventional process are performed on the RF chip 100 to form the first device 110 on its first surface. The remaining steps can be performed on the RF substrate 200 using the corresponding steps from the glass substrate process to form the second device 210 on its second surface. This reduces the processing cost of the RF module and facilitates its large-scale production and widespread adoption.

[0037] Furthermore, in this embodiment, the first surface of the RF chip 100 and the second surface of the RF substrate 200 are arranged opposite to each other, that is, the first device 110 is arranged facing the RF substrate 200, and the second device 210 is arranged facing the RF chip 100. Based on this, the first device 110 is bonded to the RF substrate 200, enabling the first device 110 to be electrically connected to the second device 210 on the second surface and the corresponding connection circuit. Through the cooperative work between the first device 110 and the second device 210, a complete RF communication circuit is formed, thereby realizing the communication function. It is understood that by arranging the first and second surfaces opposite to each other, the first device 110 can be electrically connected to the second device 210 through a shorter connection path, reducing the cost of connection wiring and reducing the loss of RF signals in the connection wiring. In some embodiments, the first and second surfaces can be arranged in opposite directions to meet specific requirements. For example, the first device 110 is arranged with its back to the RF substrate 200 and the second device 210 is arranged with its back to the RF chip 100. Alternatively, the first and second surfaces can be arranged in the same direction, i.e., the first device 110 is arranged with its back to the RF substrate 200 and the second device 210 is arranged with its back to the RF chip 100, or the first device 110 is arranged with its back to the RF substrate 200 and the second device 210 is arranged with its back to the RF chip 100.

[0038] The radio frequency module provided in this embodiment uses radio frequency chips and radio frequency substrates with different substrate materials. An active device as a first device is provided on the first surface of the radio frequency chip, and a passive device as a second device is provided on the second surface of the radio frequency substrate, wherein the first surface and the second surface are arranged opposite to each other. Through the bonding connection between the first device and the radio frequency substrate, the first device and the second device can be electrically connected. Through the cooperative work between the first device and the second device, a complete radio frequency communication circuit is formed, thereby realizing the communication function.

[0039] Compared with related technologies, this application splits the communication circuit in a conventional RF chip, retains the active devices on the RF chip, and transfers the passive devices on the RF chip to the RF substrate, thereby reducing the number of devices on the RF chip. Thus, while ensuring that the communication function is not affected, the advantages of the RF substrate over the RF chip in substrate material are utilized to effectively reduce the process complexity of the RF chip and optimize the process flow of the RF module.

[0040] Furthermore, leveraging the advantages of RF substrates over RF chips in substrate materials can reduce the processing costs required for RF modules, which is beneficial for the large-scale production and promotion of RF modules.

[0041] As one embodiment of this application, the substrate of the radio frequency chip is any one of a compound substrate, a silicon substrate, and an insulating silicon substrate.

[0042] Specifically, the radio frequency chip 100 is used to implement the first device 110, and the substrate used may include any one of a compound substrate, a silicon substrate, and an insulating silicon substrate. The first substrate material corresponding to the compound substrate is a crystal material composed of two or more elements, including but not limited to materials such as gallium arsenide, silicon carbide, indium phosphide, and gallium nitride.

[0043] Understandably, the specific type of the first substrate material can be determined according to the needs of the actual scenario. For example, the substrate material that best meets the requirements can be selected based on the performance, integration level, or cost of the RF module. For instance, in a real-world scenario where higher performance requirements are placed on the RF module, requiring it to have high output power and low noise, a compound substrate can be used as the substrate of the RF chip 100 to ensure that the RF module performs well during communication.

[0044] Similarly, real-world scenarios place higher demands on the integration of RF modules, requiring the integration of signal processing circuits capable of complex functions. In such cases, a silicon substrate can be used as the substrate for the RF chip 100 to ensure the RF module can handle complex RF signals. Furthermore, real-world scenarios require a balance between performance and integration in the RF module. In this case, an insulating silicon substrate can be used as the substrate for the RF chip 100, enabling the RF module to perform well in both dimensions.

[0045] As one embodiment of this application, the substrate of the radio frequency substrate is a glass substrate.

[0046] Specifically, the RF substrate 200 is used to implement the second device 210, and the substrate used can be a glass substrate. Compared with the resin substrate used in related technologies, the material cost of the glass substrate is lower than that of the resin substrate. With the same area of ​​the RF substrate 200, using a glass substrate can effectively reduce the material cost of the RF module. Furthermore, the glass substrate has good thermal conductivity and a low coefficient of thermal expansion, preventing heat buildup in the RF module and ensuring that it is not affected by temperature changes. This guarantees long-term stable performance of the RF module, improving its reliability and lifespan.

[0047] Furthermore, the glass substrate possesses high insulation properties, enabling the formation of a high-Q passive network when passive devices are placed on its surface. This reduces energy loss in the passive devices, improves frequency selectivity, and ensures that the overall RF performance of the RF module does not significantly degrade, maintaining a high level. It should be noted that the glass substrate also exhibits high integration and high-frequency, low-loss characteristics, allowing passive devices to be integrated with smaller linewidths and spacing, reducing the area of ​​the RF substrate 200, while also effectively reducing RF signal loss during high-frequency communication.

[0048] Reference Figure 2 As shown in the embodiment of this application, the first device includes a transistor, and bonding bumps are grown on the electrode metal layer of the transistor. The transistor is bonded to the radio frequency substrate through the bonding bumps.

[0049] Specifically, the first device 110 may include a transistor, which may include, but is not limited to, field-effect transistors and heterojunction bipolar transistors (HBTs). The transistor is used to form a multi-functional amplifier on the radio frequency chip 100, including but not limited to a driver amplifier and a power amplifier. The transistor includes electrode metal layers for electrical connection to external circuitry. These electrode metal layers correspond to different electrodes of the transistor. For a field-effect transistor, the electrodes may include a source, a gate, and a drain; for a heterojunction bipolar transistor, the electrodes may include an emitter, a base, and a collector.

[0050] Furthermore, bonding bumps 120 are grown on the electrode metal layer of the transistor. The number of bonding bumps 120 corresponds to the number of electrodes, and each bonding bump 120 corresponds to a corresponding electrode of the transistor, so that the corresponding electrodes can be electrically connected to external circuits respectively without confusion. During the packaging of the RF module, the transistor is bonded to the RF substrate 200 through the bonding bumps 120, so that the transistor die is connected to the surface of the RF substrate 200, realizing the electrical connection between the first device 110 and the second device 210, so that a communication circuit with complete communication function can be formed through the cooperative work between the first device 110 and the second device 210.

[0051] Understandably, by aligning the first and second surfaces and bonding the transistor to the RF substrate 200 via bonding bumps 120, this connection method allows the first device 110 to be electrically connected to the second device 210 via a shorter connection path. This shortens the interconnection path between the first device 110 and the second device 210, thereby reducing parasitic parameters in the communication circuit and effectively improving the performance of the RF module. Furthermore, the bonding method using bonding bumps 120 also improves the heat dissipation of the RF module, reducing the impact of heat generated during operation on the RF module.

[0052] As one embodiment of this application, the sum of the heights of the bonding protrusion and the first device is greater than the height of the second device.

[0053] Specifically, the bonding bump 120 is grown on the electrode metal layer of the first device 110. The first device 110 is bonded to the RF substrate 200 through the bonding bump 120. Therefore, the vertical distance between the RF chip 100 and the RF substrate 200 can be determined based on the respective heights of the first device 110 and the bonding bump 120. Since the first surface and the second surface are arranged opposite each other, the second device 210 can also be located between the RF chip 100 and the RF substrate 200. To avoid collisions between the second device 210 and the RF chip 100, which could damage the RF chip 100 or the second device 210 and affect the function of the RF module, the sum of the heights of the bonding bump 120 and the first device 110 needs to be greater than the height of the second device 210, so as to reserve sufficient space for the second device 210 between the RF chip 100 and the RF substrate 200.

[0054] As one embodiment of this application, the second device includes two or more passive devices.

[0055] Specifically, in this embodiment, the second device 210 on the RF substrate 200 includes at least two passive devices. When the second device 210 includes only two passive devices, their types may include filters and RF switches, so that the RF module has the functions of frequency selection and path control.

[0056] In some embodiments, in addition to filters and RF switches, other types of passive devices may be provided on the RF substrate 200, including but not limited to capacitors, inductors, matching networks, impedance transformation networks, filter networks, and couplers. For example, when the first device 110 is a transistor, the surface of the RF chip 100 forms a multi-stage amplifier structure including a driver amplifier and a power amplifier through transistors. Different amplifiers can be matched and connected through impedance transformation networks to achieve maximum power transfer between amplifiers and improve the signal transmission performance of the RF module.

[0057] As one embodiment of this application, a metal wiring is provided on the second surface, and the first device is electrically connected to the second device through the metal wiring.

[0058] Specifically, a second device 210 and a metal wiring 220 are formed on the second surface of the RF substrate 200, and the second device 210 is electrically connected to the metal wiring 220. After the first device 110 is bonded to the RF substrate 200, the first device 110 is electrically connected to the metal wiring 220 through the bonding bump 120. At this time, the first device 110 and the second device 210 are electrically connected through the metal wiring 220 and the bonding bump 120, forming a communication circuit with complete functionality.

[0059] It is understandable that the metal wiring layer 220 typically occupies a large area on the substrate surface. If the metal wiring layer 220 is formed on the surface of the RF chip 100, it will limit the area of ​​the RF chip 100, preventing the area of ​​the RF chip 100 from being reduced, thereby increasing the material cost required for the RF chip 100. Therefore, in this embodiment, the metal wiring 220 is implemented on the RF substrate 200, and the second device 210 can be implemented using a second substrate material with lower material cost, thereby effectively reducing the surface area of ​​the RF chip 100 and reducing the material cost of the RF chip 100.

[0060] As one embodiment of this application, there are multiple first devices, metal wiring and second devices forming a functional circuit on the second surface, and the first devices are electrically connected to each other through the functional circuit.

[0061] Reference Figure 3 As shown, the number of first devices 110 on the RF chip 100 can be one or more. When there are multiple first devices 110, the first devices 110 can be electrically connected directly through their respective bonding bumps 120 and metal wiring 220 on the second surface, or they can be electrically connected through the metal wiring 220 and the functional circuit formed on the second surface by the second device 210.

[0062] It is understood that the functional circuit can be a matching network, impedance transformation network, filter network, and coupler, etc., used to provide matching circuits between different first devices 110, realize high-performance interconnection between the first devices 110, and improve the signal transmission performance of the RF module.

[0063] This application also provides a communication device that includes the radio frequency module described in any of the above embodiments.

[0064] Reference Figure 4 As shown, this application also provides a method for fabricating an radio frequency module, the method comprising: S410. Provides an RF chip and an RF substrate; wherein the RF chip includes a first surface and the RF substrate includes a second surface.

[0065] S420. Using a first photomask, a first device is formed on a first surface by photolithography and etching; wherein the first device includes an electrode metal layer for electrical connection.

[0066] S430. A second device and metal wiring are formed on a second surface by photolithography and etching using a second photomask.

[0067] S440. Bonding protrusions are grown on the electrode metal layer.

[0068] S450. The first surface is placed relative to the second surface, and the first device is bonded to the radio frequency substrate by bonding bumps to obtain a radio frequency module; wherein the first device and the second device are electrically connected by metal wiring and bonding bumps.

[0069] Reference Figures 5a to 5c As shown, for the RF chip 100, firstly, a chip substrate prepared using a first substrate material is provided as the substrate of the RF chip 100. Secondly, a first photomask corresponding to the RF chip 100 is designed according to the communication requirements of the RF module. Photolithography is performed on the first surface of the chip substrate using the first photomask to transfer the device pattern of the first device 110 to the first surface. Based on this, etching is performed on the first surface according to the device pattern of the first device 110 to form the first device 110 including an electrode metal layer, thus completing the processing of the RF chip 100. Finally, bump growth is performed on the electrode metal layer of the first device 110 to obtain bonding bumps 120 for bonding with the RF substrate 200.

[0070] Reference Figures 6a to 6b As shown, for the RF substrate 200, firstly, a substrate made of a second substrate material is provided as the substrate of the RF substrate 200. Secondly, a second photomask corresponding to the RF substrate 200 is designed according to the communication requirements of the RF module. Photolithography is performed on the second surface of the substrate using the second photomask to transfer the device pattern of the second device 210 to the second surface. Based on this, etching is performed on the second surface according to the device pattern of the second device 210 to form the second device 210 and the metal wiring 220, thus completing the processing of the RF substrate 200.

[0071] Furthermore, the RF substrate 200 is placed with its second surface facing upwards, and the RF chip 100 is inverted, that is, the RF chip 100 is placed on the RF substrate 200 with its first surface facing downwards at the corresponding position. The first device 110 is then bonded to the RF substrate 200 using the bonding bumps 120. It is understood that the second surface of the RF substrate 200 has a second device 210 and metal wiring 220. After the first device 110 completes the bonding connection, it is electrically connected to the second device 210 through the metal wiring 220 and the bonding bumps 120, thereby forming a communication circuit with complete communication functions, thus obtaining an RF module.

[0072] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0074] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0075] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A radio frequency module, characterized by, The application relates to a radio frequency module. The radio frequency chip is provided with a first device on a first surface thereof; The radio frequency substrate is provided with a second device on a second surface thereof; The first surface and the second surface are oppositely arranged, the first device is bonded to the radio frequency substrate, and the first device and the second device are electrically connected; The radio frequency chip and the radio frequency substrate are made of different substrate materials, the first device is an active device, and the second device is a passive device.

2. The radio module of claim 1, wherein, The substrate of the radio frequency chip is any one of a compound substrate, a silicon substrate and an insulating silicon substrate.

3. The radio module of claim 1, wherein, The substrate of the radio frequency substrate is a glass substrate.

4. The radio module of claim 1, wherein, The first device comprises a transistor, a bonding bump is grown on an electrode metal layer of the transistor, and the transistor is bonded to the radio frequency substrate through the bonding bump.

5. The radio module of claim 4, wherein, The sum of the height of the bonding bump and the height of the first device is higher than the height of the second device.

6. The radio module of claim 1, wherein, The second device comprises two or more passive devices.

7. The radio module of claim 1, wherein, The second surface is provided with a metal wiring, and the first device is electrically connected to the second device through the metal wiring.

8. The radio module of claim 7, wherein, The number of the first devices is plural, the metal wiring and the second device form a functional circuit on the second surface, and the first devices are electrically connected through the functional circuit.

9. A communication device, characterized by The communication device comprises the radio frequency module as claimed in any one of claims 1 to 8.

10. A method for fabricating a radio frequency module, characterized in that, The method comprises: providing a radio frequency chip and a radio frequency substrate, wherein the radio frequency chip comprises a first surface, and the radio frequency substrate comprises a second surface; using a first mask to form a first device on the first surface through photoetching and etching, wherein the first device comprises an electrode metal layer for electrical connection; using a second mask to form a second device and a metal wiring on the second surface through photoetching and etching; growing a bonding bump on the electrode metal layer; arranging the first surface relative to the second surface, bonding the first device to the radio frequency substrate through the bonding bump to obtain the radio frequency module, wherein the first device and the second device are electrically connected through the metal wiring and the bonding bump.

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