Package structure and method of forming the same

Abstract

This invention provides a packaging structure and its forming method. By directly forming the antenna element on the surface of a ceramic substrate, it replaces the secondary integration of prefabricated antenna modules, effectively simplifying the packaging process and directly reducing material and manufacturing costs. Simultaneously, by eliminating the additional assembly interface between the antenna module and the substrate, it significantly reduces accuracy deviations caused by mismatches in the thermal expansion coefficients of different components and accumulated tolerances, achieving higher integration accuracy and stricter process tolerance control.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a packaging structure and a method for forming the same. Background Technology

[0002] With the development of 5G, satellite communications, and automotive radar, operating frequency bands are shifting from Sub-6GHz to millimeter waves (30-300GHz). High-frequency signals suffer significant transmission losses in traditional PCB traces, and their extremely short wavelengths make them highly sensitive to the manufacturing tolerances and installation precision of external antenna components. Traditional solutions combining chips and external antennas face bottlenecks in performance, size, and cost.

[0003] Against this backdrop, AIP (Antenna-in-Package) technology emerged. AIP integrates the antenna from the PCB board into the chip package, creating an ultra-short-range, low-loss signal path from the chip to the antenna. This solves the critical loss problem in millimeter-wave transmission, while modularizing and miniaturizing the entire RF front-end, significantly lowering the design threshold for downstream applications. Therefore, AIP is not merely a change in antenna location, but a paradigm shift from discrete design to system integration. It represents the future direction of high-performance, miniaturized RF front-ends and is a key enabling technology supporting next-generation wireless communication and sensing applications.

[0004] However, while current AIP technology has achieved system-integrated design, it typically manufactures the antenna as a separate antenna module, integrates it onto the packaging substrate, and then encapsulates it. This process of manufacturing the antenna module separately not only increases the overall cost, but also introduces significant process tolerances due to the separate processing of the antenna module and the package, making it difficult to meet the requirements of high-precision integration. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a packaging structure and a method for forming the same, which can realize the integrated manufacturing of antenna and package, thereby reducing manufacturing costs and achieving good process tolerance control.

[0006] To address the aforementioned problems, the present invention provides a method for forming a package structure, comprising: providing a lead frame, the lead frame including a frame unit, the frame unit including a ceramic substrate island and metal pins disposed around the ceramic substrate island; forming an antenna unit in an antenna mounting area on the upper surface of the ceramic substrate island; mounting a chip in a chip mounting area on the upper surface of the ceramic substrate island; wire bonding for electrically connecting the chip to the antenna unit via a first lead and to the metal pins via a second lead; and molding to form a molding compound, the molding compound covering the lead frame, the antenna unit, the chip, the first lead, and the second lead, wherein the molding compound does not cover the lower surface of the ceramic substrate island and the lower surface of the metal pins.

[0007] In one embodiment, the step of providing a lead frame further includes: the metal pins being disposed on the periphery of the ceramic substrate island near the chip mounting area.

[0008] In one embodiment, the step of forming an antenna element in the antenna placement area on the upper surface of the ceramic substrate island further includes: forming a metal layer in the antenna placement area on the upper surface of the ceramic substrate island; and patterning the metal layer to form the antenna element.

[0009] In one embodiment, the step of forming a metal layer in the antenna mounting area on the upper surface of the ceramic substrate further includes: forming the metal layer using a direct copper plating process, or forming the metal layer using a direct copper cladding process, or forming the metal layer using an active metal brazing process.

[0010] In one embodiment, the step of forming an antenna element in the antenna placement area on the upper surface of the ceramic substrate further includes: forming the antenna element on the upper surface of the ceramic substrate using a screen printing process.

[0011] In one embodiment, the step of forming an antenna element in the antenna setting area on the upper surface of the ceramic substrate further includes: the antenna element includes a radiating array and a feed line connected to the radiating array; the wire bonding step further includes: the chip is electrically connected to the feed line through the first lead.

[0012] In one embodiment, the step of forming an antenna element in the antenna setting area on the upper surface of the ceramic substrate island further includes: forming at least one receiving antenna element and at least one transmitting antenna element on the upper surface of the ceramic substrate island.

[0013] In one embodiment, the step of forming at least one receiving antenna unit and at least one transmitting antenna unit on the upper surface of the ceramic substrate island further includes: the receiving antenna unit and the transmitting antenna unit being disposed opposite each other at opposite corners of the ceramic substrate island.

[0014] In one embodiment, the step of mounting a chip in the chip mounting area on the surface of the ceramic substrate island further includes: mounting the chip in the chip mounting area on the surface of the ceramic substrate island using a surface mount process.

[0015] In one embodiment, the step of providing a lead frame further includes: the lead frame further includes a pre-molding layer disposed between the ceramic substrate island and the metal pin; the step of molding to form a molded body further includes: the molded body further covering the surface of the pre-molding layer.

[0016] In one embodiment, the method further includes the step of forming a thermally conductive layer on the lower surface of the ceramic substrate island.

[0017] In one embodiment, the method further includes the step of forming an electromagnetic shield that electromagnetically isolates the antenna unit from the chip.

[0018] In one embodiment, the step of forming an electromagnetic shielding cover further includes: forming an electromagnetic shielding wall between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island; molding, the step of forming a molded body further includes: the molded body further covers the electromagnetic shielding wall, and the top surface of the electromagnetic shielding wall is exposed on the top surface of the molded body; after the step of forming the molded body, the step further includes: forming an electromagnetic shielding layer on the top surface and part of the side surface of the molded body, the electromagnetic shielding layer being in contact with the top surface of the electromagnetic shielding wall to form the electromagnetic shielding cover, and the chip being located inside the electromagnetic shielding cover.

[0019] In one embodiment, the step of forming an electromagnetic shielding wall between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island further includes: the electromagnetic shielding wall is made of a metal plate and has a gap at the first lead position, through which the first lead passes.

[0020] In one embodiment, the step of forming an electromagnetic shielding wall between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island further includes: the electromagnetic shielding wall is composed of a plurality of metal pillars arranged at a set interval, and the first lead passes through the gap between two adjacent metal pillars.

[0021] In one embodiment, the step of forming an electromagnetic shielding layer on the top surface and part of the side surface of the encapsulated body further includes: the electromagnetic shielding layer is a metal plate, and the step of forming the electromagnetic shielding layer further includes: the metal plate is attached to the top surface and part of the side surface of the encapsulated body by an adhesive layer.

[0022] In one embodiment, the step of forming an electromagnetic shielding layer on the top surface and part of the side surface of the molded body further includes: forming the electromagnetic shielding layer on the top surface and part of the side surface of the molded body using physical or chemical processes.

[0023] In one embodiment, the step of providing a lead frame further includes: dividing the lead frame into a plurality of frame units by a dicing groove; and molding, the step of forming a molded body further includes: cutting along the dicing groove to form a plurality of independent package structures such that the sides of the metal pins are exposed to the sides of the molded body.

[0024] This invention also provides a packaging structure, including: a lead frame including a ceramic substrate island and metal pins disposed around the periphery of the ceramic substrate island; an antenna unit formed in an antenna mounting area on the upper surface of the ceramic substrate island; a chip mounted in a chip mounting area on the upper surface of the ceramic substrate island and electrically connected to the antenna unit via a first lead and electrically connected to the metal pins via a second lead; and a molding compound covering the lead frame, the antenna unit, the chip, the first lead, and the second lead, wherein the molding compound does not cover the lower surface of the ceramic substrate island and the lower surface of the metal pins.

[0025] In one embodiment, the metal pins are disposed around the periphery of the chip mounting area.

[0026] In one embodiment, the antenna unit includes a radiating array and a feed line connected to the radiating array, and the chip is electrically connected to the feed line via the first lead.

[0027] In one embodiment, the radiating array and the feed line are located on the same layer.

[0028] In one embodiment, the packaging structure includes at least one receiving antenna element and at least one transmitting antenna element.

[0029] In one embodiment, the receiving antenna unit and the transmitting antenna unit are disposed diagonally opposite each other on the ceramic substrate island.

[0030] In one embodiment, the chip is attached to the surface of the ceramic substrate island via an adhesive layer.

[0031] In one embodiment, a pre-molding layer is further included, the pre-molding layer being disposed between the ceramic substrate island and the metal pin, and the molding compound further covering the surface of the pre-molding layer.

[0032] In one embodiment, a thermally conductive layer is further included, the thermally conductive layer being disposed on the lower surface of the ceramic substrate island.

[0033] In one embodiment, an electromagnetic shielding cover is further included, with the chip located inside the electromagnetic shielding cover. The electromagnetic shielding cover includes: an electromagnetic shielding wall disposed between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island, the molding compound further covering the electromagnetic shielding wall, and the top surface of the electromagnetic shielding wall exposed on the top surface of the molding compound; and an electromagnetic shielding layer disposed on the top surface and part of the side surface of the molding compound, and in contact with the top surface of the electromagnetic shielding wall.

[0034] In one embodiment, the electromagnetic shielding wall is made of a metal plate and has a gap at the location of the first lead, through which the first lead passes.

[0035] In one embodiment, the electromagnetic shielding wall is composed of a plurality of metal pillars arranged at a set interval, and the first lead passes through the gap between two adjacent metal pillars.

[0036] In one embodiment, the electromagnetic shielding layer is adhered to the top surface and part of the side surface of the encapsulation by an adhesive layer.

[0037] In one embodiment, the side of the metal pin is exposed to the side of the molding compound.

[0038] The above-mentioned technical solution directly forms the antenna element on the surface of the ceramic substrate island, replacing the secondary integration of prefabricated antenna modules. This effectively simplifies the packaging process, eliminating the need for separate module manufacturing, procurement, handling, and assembly of the antenna element, thereby directly reducing material and manufacturing costs. Simultaneously, by eliminating the additional assembly interface between the antenna module and the substrate island, it significantly reduces accuracy deviations caused by mismatches in the thermal expansion coefficients of different components and accumulated tolerances, achieving higher integration accuracy and stricter process tolerance control. Furthermore, the antenna element and the chip are directly connected on the same ceramic substrate island via an extremely short first lead, constructing an ultra-short high-frequency signal transmission path, minimizing feed loss, and improving antenna efficiency and overall system RF performance. In addition, the packaging structure and its formation method provided by this invention fully utilize the high thermal conductivity and excellent mechanical stability of the ceramic substrate island, not only enhancing the heat dissipation capacity of the packaging structure but also ensuring its long-term reliability under operating conditions such as thermal cycling.

[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the steps in a method for forming a packaging structure according to an embodiment of the present invention; Figure 2 This is a top view schematic diagram of the lead frame in a method for forming a packaging structure according to an embodiment of the present invention; Figure 3 It is along Figure 2 A schematic diagram of the cross-section along the A-A1 direction; Figure 4 This is a schematic cross-section of the metal layer formed in a method for forming an encapsulation structure according to an embodiment of the present invention; Figure 5 This is a top view schematic diagram of the antenna element formed in the method for forming the packaging structure provided in an embodiment of the present invention; Figure 6 It is along Figure 5 A schematic diagram of the cross-section along the A-A1 direction; Figure 7 This is a top view schematic diagram of a packaged chip in a method for forming a packaging structure according to an embodiment of the present invention; Figure 8 It is along Figure 7 A schematic diagram of the cross-section along the A-A1 direction; Figure 9 This is a top view schematic diagram of wire bonding in a method for forming a packaging structure according to an embodiment of the present invention; Figure 10 It is along Figure 9 A schematic diagram of the cross-section along the A-A1 direction; Figure 11 This is a top view schematic diagram of the molding process in the packaging structure formation method provided in an embodiment of the present invention; Figure 12 It is along Figure 11 A schematic diagram of the cross-section along the A-A1 direction; Figure 13 This is a cross-sectional schematic diagram of the encapsulation structure formed in the encapsulation structure forming method provided in an embodiment of the present invention; Figure 14 This is a cross-sectional schematic diagram of the formation of a thermally conductive layer in a method for forming an encapsulation structure according to another embodiment of the present invention; Figure 15 This is a cross-sectional schematic diagram of the lead frame in a method for forming a packaging structure according to another embodiment of the present invention; Figure 16 This is a cross-sectional schematic diagram of the encapsulation in the method for forming the encapsulation structure provided in another embodiment of the present invention; Figure 17 This is a top view schematic diagram of the method for forming an electromagnetic shielding wall in the packaging structure forming method provided in another embodiment of the present invention; Figure 18 This is a side view of the electromagnetic shielding wall in a method for forming an encapsulation structure according to another embodiment of the present invention; Figure 19 This is a top view schematic diagram of the molding process in the method for forming the packaging structure provided in another embodiment of the present invention; Figure 20 It is along Figure 19 A schematic diagram of the cross-section along the A-A1 direction; Figure 21 This is a top view schematic diagram of the method for forming an electromagnetic shielding layer in the packaging structure formation method provided in another embodiment of the present invention; Figure 22 It is along Figure 21 A schematic diagram of the cross-section along the A-A1 direction; Figure 23 This is another top view schematic diagram of the method for forming an electromagnetic shielding wall in another embodiment of the present invention.

[0042] Explanation of reference numerals in the attached figures: 200 lead frame 201 frame unit 202 Connecting Reinforcement Structure 203 outer frame 204 cutting track 210 Ceramic Base Island 210A antenna setting area 210B chip mounting area 220 metal pins 300 antenna elements 310 radiation array 320 feeder line 400 metal layers 500 chip 510 First Lead 520 second lead 600 molded body 700 thermal conductive layer 800 Pre-molded Seal 900 Electromagnetic Shielding Cover 910 Electromagnetic Shielding Wall 911 Gap 920 electromagnetic shielding layer. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Figure 1 This is a schematic diagram illustrating the steps of a method for forming a packaging structure according to an embodiment of the present invention, as shown below. Figure 1 As shown, the forming method includes: step S10, providing a lead frame, the lead frame including a frame unit, the frame unit including a ceramic substrate island and metal pins disposed around the ceramic substrate island; step S11, forming an antenna unit in an antenna mounting area on the upper surface of the ceramic substrate island; step S12, mounting a chip in a chip mounting area on the upper surface of the ceramic substrate island; step S13, wire bonding, for electrically connecting the chip to the antenna unit via a first lead and to the metal pins via a second lead; step S14, molding, forming a molding compound, the molding compound covering the lead frame, the antenna unit, the chip, the first lead and the second lead, wherein the molding compound does not cover the lower surface of the ceramic substrate island and the lower surface of the metal pins.

[0045] The packaging structure formation method provided in this invention effectively simplifies the packaging process, eliminating the need for separate module manufacturing, procurement, handling, and assembly of antenna elements, thereby directly reducing material and manufacturing costs. Simultaneously, it significantly reduces accuracy deviations caused by mismatched thermal expansion coefficients and accumulated tolerances among different components, achieving higher integration accuracy and stricter process tolerance control. Furthermore, it constructs an ultra-short high-frequency signal transmission path, minimizing feed loss and improving antenna efficiency and overall system RF performance. In addition, it fully utilizes the high thermal conductivity and excellent mechanical stability of the ceramic substrate island, enhancing the heat dissipation capacity of the packaging structure and ensuring its long-term reliability under operating conditions such as thermal cycling.

[0046] Figures 2-13 This is a process flow diagram of a method for forming a packaging structure according to an embodiment of the present invention. The following is in conjunction with... Figures 1-13 A method for forming a packaging structure according to an embodiment of the present invention will be described in detail.

[0047] Step S10: A lead frame 200 is provided, the lead frame 200 including a frame unit 201, the frame unit 201 including a ceramic substrate island 210 and metal pins 220 disposed around the ceramic substrate island 210. Figure 2 and Figure 3 As shown, where, Figure 2This is a top view of the lead frame 200 in a method for forming a packaging structure according to an embodiment of the present invention; Figure 3 It is along Figure 2 A cross-sectional schematic diagram along the A-A1 direction, wherein the ceramic substrate island 210 serves as chip 500 (labeled as...). Figure 7 ) and antenna element 300 (marked in Figure 4 The ceramic substrate 210 serves as the carrier for the electromagnetic wave. Its high dielectric constant significantly shortens the electromagnetic wave wavelength, enabling miniaturization of the packaging structure. Its low dielectric loss ensures high efficiency in high-frequency signal radiation and reduces energy loss. Excellent temperature stability minimizes the drift of the antenna resonant frequency with environmental changes, ensuring operational reliability. Furthermore, the ceramic substrate 210 possesses high thermal conductivity and excellent mechanical stability, enhancing the heat dissipation capacity of the packaging structure and guaranteeing its long-term reliability under thermal cycling and other operating conditions.

[0048] In some embodiments, the ceramic substrate 210 is made of materials including alumina (Al2O3), aluminum nitride (AlN), and silicon nitride (Si3N4). Alumina is low in cost and has good insulation properties; aluminum nitride has excellent thermal conductivity, and its coefficient of thermal expansion is highly matched with that of silicon chips, effectively reducing thermal stress; silicon nitride exhibits outstanding mechanical strength and thermal shock resistance, and its low coefficient of thermal expansion allows it to maintain structural stability under high-temperature cycling conditions. Furthermore, signal transmission loss can be reduced by optimizing the dielectric constant of the ceramic substrate 210, thereby meeting the requirements of low loss and high integration for high-frequency applications such as 5G millimeter-wave and terahertz communication.

[0049] The ceramic substrate island 210 is divided into an antenna setting area 210A and a chip mounting area 210B. In subsequent processes, the antenna setting area 210A serves as the area for forming the antenna unit 300, and the chip mounting area 210B serves as the area for setting the chip 500.

[0050] In some embodiments, the ceramic base island 210 may include one or more independent antenna mounting areas 210A, each of which may form one or more antenna elements 300. For example, in this embodiment, the ceramic base island 210 includes two antenna mounting areas 210A, which are used in subsequent processes to form a receiving antenna element and a transmitting antenna element, respectively, to achieve full-duplex communication. Furthermore, the two antenna mounting areas 210A are arranged diagonally opposite each other on the ceramic base island 210, so as to maximize the distance between the receiving antenna element and the transmitting antenna element formed in subsequent processes by utilizing the diagonal distance of the ceramic base island 210, thereby effectively suppressing near-field coupling and far-field interference between the receiving antenna element and the transmitting antenna element.

[0051] In some embodiments, the final package structure includes one chip 500, in which case the ceramic substrate island 210 includes one chip mounting area 210B; in other embodiments, the final package structure includes multiple chips 500, in which case the ceramic substrate island 210 includes multiple chip mounting areas 210B. The position of the chip mounting areas 210B can be arranged according to the position of the antenna mounting area 210A to ensure the shortest possible RF front-end signal path and optimal electromagnetic compatibility (EMC) performance.

[0052] In some embodiments, the ceramic base island 210 is mechanically connected to the outer frame 203 of the lead frame 200 via a connecting rib structure 202, thereby ensuring the positioning and support stability of the ceramic base island 210 in the early stages of the packaging process. In the molding compound 600 (labeled as...) Figure 12 After molding, the connecting rib structure 202 is cut off by a precise cutting process to disconnect the ceramic base island 210 from the outer frame 203 of the lead frame 200, thereby forming an independent packaging structure.

[0053] The metal pin 220 is disposed around the ceramic base island 210, and its upper surface near one end of the ceramic base island 210 is connected by a second lead 520 (marked as...). Figure 9 The metal pin 220 is electrically connected to the input / output pads of the chip 500, and its lower surface at the end furthest from the ceramic substrate island 210 serves as the external connection point for the final package structure. Further, in some embodiments, the cross-section of the metal pin 220 is inverted trapezoidal or has a stepped structure to enhance its bonding strength with the molding compound 600. In some embodiments, the metal pin 220 is integrally formed from a highly conductive material such as a copper alloy or an iron-nickel alloy, and a nickel / gold or nickel / palladium / gold plating layer is plated on the bonding area surface, which enhances the solderability and oxidation resistance of the metal pin 220 and ensures the quality of the intermetallic compound formation at the bonding interface.

[0054] In some embodiments, the lead frame 200 includes a plurality of metal pins 220, which can be configured as a functional group including power pins, ground pins, and signal pins. The metal pins 220 are arranged in an equidistant circular array or with non-uniform spacing according to signal integrity requirements.

[0055] Furthermore, in one embodiment, the metal pin 220 is disposed on the periphery of the chip mounting area 210B, that is, the metal pin 220 is disposed on the periphery of the ceramic substrate island 210 near the chip mounting area 210B, so that the linear spacing between the pads of the chip 500 and the bonding area corresponding to the metal pin 220 is minimized, thereby reducing the physical length of the second lead 520 connecting the chip 500 and the metal pin 220, enhancing the mechanical stability of the bonding point, improving its fatigue resistance under temperature cycling and mechanical vibration, and thus improving the reliability of the packaging structure in harsh environments.

[0056] In some embodiments, the lead frame 200 is divided into a plurality of frame units 201 by a cutting channel 204. Two frame units 201 are schematically illustrated in the accompanying drawings of this embodiment.

[0057] In some embodiments, the lead frame 200 is divided into a plurality of regularly arranged frame units 201 by a predetermined dicing channel 204, which serves as a precise path for subsequent package separation. The accompanying drawings of this embodiment schematically illustrate two adjacent frame units 201, with the dicing channel 204 between them. In some embodiments, the dicing channel 204 may contain specific stress-relieving structures, such as openings, to alleviate thermal stress and reduce the generation of metal burrs during cutting. The connection points of the frame units 201 at the dicing channel 204 may be partially etched to reduce the metal thickness, thereby ensuring the smoothness of the package edges and electrical safety during final separation.

[0058] Step S11: An antenna element 300 is formed in the antenna mounting area 210A on the upper surface of the ceramic substrate island 210. For example... Figure 5 and Figure 6 As shown, where, Figure 5 This is a top view schematic diagram of the formation of antenna element 300 in a method for forming a packaging structure according to an embodiment of the present invention. Figure 6 It is along Figure 5 A schematic diagram of the cross section along the A-A1 direction.

[0059] The antenna unit 300 is used to achieve efficient energy conversion between guided waves and free-space electromagnetic waves. Specifically, in the transmission path, the antenna unit 300 converts the high-frequency electrical signal processed by the chip 500 into electromagnetic waves and radiates them into space. In the receiving path, the antenna unit 300 captures electromagnetic waves in space and converts them into electrical signals, which are then fed into the chip 500 for processing.

[0060] This step directly fabricates the antenna element 300 on the upper surface of the ceramic substrate island 210, fully utilizing the high dielectric constant of ceramic materials. This allows for a significant reduction in the physical size of the antenna in high-frequency bands such as millimeter waves, thereby achieving miniaturization and integration of the packaging structure. Simultaneously, the inherent low dielectric loss characteristics of the ceramic substrate island 210 help reduce signal energy attenuation during transmission, thus improving the antenna's radiation efficiency.

[0061] Furthermore, in some embodiments, a plurality of antenna elements 300 are formed on the antenna mounting area 210A on the upper surface of the ceramic substrate island 210. Each antenna element 300 can serve as a receiving channel or a transmitting channel to achieve full-duplex communication. For example, in this embodiment, one receiving antenna element and one transmitting antenna element are formed in this step to achieve full-duplex communication. Furthermore, two antenna elements 300 are arranged diagonally opposite each other on the ceramic substrate island 210 to maximize the distance between the receiving antenna element and the transmitting antenna element using the diagonal distance of the ceramic substrate island 210. This effectively suppresses near-field coupling and far-field interference between the receiving antenna element and the transmitting antenna element. Combined with the high heat dissipation performance of the ceramic substrate island 210, the stability and reliability of the antenna elements 300 under high-power operating conditions are ensured.

[0062] Furthermore, in some embodiments, the antenna element 300 includes a radiating array 310 and a feed line 320 connected to the radiating array 310, wherein the radiating array 310 and the feed line 320 are formed synchronously.

[0063] As an example, in one embodiment, the step of forming an antenna element 300 in the antenna placement area 210A on the upper surface of the ceramic substrate island 210 further includes: A metal layer 400 is formed on the antenna mounting area 210A on the upper surface of the ceramic substrate island 210. For example... Figure 4 The diagram shown is a cross-sectional schematic of the formation of a metal layer 400 in a method for forming a packaging structure according to an embodiment of the present invention. In this step, the metal layer 400 is also formed in other areas on the upper surface of the ceramic substrate island 210.

[0064] The metal layer 400 covers the upper surface of the ceramic substrate island 210. The thickness of the metal layer 400 can be set according to the electrical and mechanical performance requirements of the antenna element 300 formed by subsequent patterning. The material of the metal layer 400 may include highly conductive materials, such as copper, silver, aluminum, and their alloys.

[0065] In one embodiment, the metal layer 400 is formed using a direct copper plating (DPC) process. Specifically, a highly adhesive titanium / chromium layer is first deposited on the surface of the ceramic substrate island 210 by magnetron sputtering; a very thin copper layer is sputtered onto the titanium / chromium layer as a seed layer for electroplating; and the copper layer is thickened to the required thickness using electroplating.

[0066] In one embodiment, the metal layer 400 is formed using a direct copper cladding (DBC) process. This process achieves bonding at high temperatures through a eutectic reaction between copper and ceramic. Specifically, after stacking copper foil and ceramic substrate island 210, the mixture is heated to a eutectic temperature of 1065-1083°C and held in an oxygen-containing nitrogen protective atmosphere. At this temperature, copper and oxygen form a Cu-O eutectic liquid, which reacts with the ceramic surface (such as Al2O3) to generate an intermediate phase (such as CuAlO2), thereby achieving a chemical metallurgical bond between copper and ceramic. After bonding is completed, the mixture is cooled through a controlled cooling process to reduce thermal stress.

[0067] In one embodiment, the metal layer 400 is formed using an active metal brazing (AMB) process. This process achieves a high-strength connection between copper and ceramic in a vacuum furnace using a special brazing filler metal containing active elements such as titanium and zirconium. The active elements can chemically react with the ceramic surface to achieve a high-strength connection. Specifically, the brazing filler metal is precisely printed onto the surface of the ceramic substrate island 210 using thick-film screen printing technology; copper foil is then placed on the brazing filler metal-coated ceramic substrate island 210 and sintered in a vacuum sintering furnace. Under vacuum and high temperature, the brazing filler metal melts, and the active elements (such as titanium) react chemically with the ceramic surface to form strong chemical bonds, thereby "brazing" the copper foil onto the ceramic. The vacuum environment prevents oxidation and ensures the connection quality between the copper foil and the ceramic substrate island 210.

[0068] After forming the metal layer 400, the metal layer 400 is patterned to form the antenna element 300. For example... Figure 5 and Figure 6 As shown.

[0069] In some embodiments, the metal layer 400 is patterned using photolithography and etching techniques. Specifically, the step of patterning the metal layer 400 further includes: coating or laminating a layer of photoresist or photosensitive dry film as a resist layer on the surface of the metal layer 400; exposing the resist layer to ultraviolet light using a pre-designed antenna pattern mask to cause a chemical reaction in the resist layer on the metal areas to be retained; dissolving and removing the unexposed (positive resist) or exposed (negative resist) portions of the resist layer with a developing solution, thereby transferring the antenna pattern onto the resist layer and exposing the metal areas to be etched away; selectively etching the exposed metal with an acidic or alkaline etching solution (such as ferric chloride or ammonia system) to remove the metal not protected by the resist layer; removing the residual resist layer using chemical stripping or plasma stripping, and finally obtaining the precisely shaped antenna unit 300 on the ceramic substrate island 210.

[0070] As an example, in another embodiment, the step of forming the antenna element 300 in the antenna placement area 210A on the upper surface of the ceramic substrate island 210 further includes: forming the antenna element 300 on the upper surface of the ceramic substrate island 210 using a screen printing process. This step directly forms the antenna element 300 on the surface of the ceramic substrate island 210 using a screen printing process, omitting the traditional multiple processes such as photolithography, development, and etching. By printing the conductive paste in one step and sintering it at high temperature, not only is the process cycle shortened, significantly improving production efficiency and economy, but also reducing the deviations that may be introduced by multi-step processing, thereby better controlling the shape accuracy and positional accuracy of the antenna element 300.

[0071] Furthermore, in some embodiments, the antenna element 300 is formed by printing and sintering a metal paste containing conductive phase particles such as silver, copper, and aluminum. Specifically, the metal paste containing conductive phase particles such as silver, copper, and aluminum is first precisely coated onto a preset pattern on the ceramic substrate 210 by screen printing. After printing, the ceramic substrate 210 needs to undergo a drying and high-temperature sintering process. During the sintering process, the metal particles are densified and fused together at high temperature, and at the same time, the glass frit and other components in the paste react with the ceramic surface to form mechanical interlocking and alloy bonding.

[0072] Step S12: The chip 500 is mounted on the chip mounting area 210B on the upper surface of the ceramic substrate island 210. For example... Figure 7 and Figure 8 As shown, where, Figure 7 This is a top view schematic diagram of the packaged chip 500 in the method for forming a packaging structure according to an embodiment of the present invention. Figure 8 It is along Figure 7 A schematic diagram of the cross section along the A-A1 direction.

[0073] The chip 500 includes a functional side and a back side. In this step, the back side of the chip 500 is attached to the upper surface of the ceramic substrate 210 via an adhesive layer (not shown in the figures), while the functional side of the chip 500 faces away from the ceramic substrate 210. The chip 500 can be a millimeter-wave chip, an RF front-end chip, a power amplifier, or a low-noise amplifier. The functional side of such chips typically includes pads for signal input / output and active circuit areas. The back-mount method allows the heat generated by the chip 500 to be efficiently conducted to the ceramic substrate 210, which has a high thermal conductivity, through the thermal interface material between the back side and the ceramic substrate 210. Simultaneously, the upward orientation of the functional side provides a convenient process interface for subsequent electrical connections with the antenna unit 300 and the metal pins 220 via wire bonding. This mounting structure is particularly beneficial for high-frequency chips such as millimeter-wave chips, shortening the signal transmission path and optimizing heat dissipation and electromagnetic performance.

[0074] In some embodiments, this step involves mounting one or more chips 500 on the upper surface of the ceramic substrate island 210. The position of the chip 500 can be arranged according to the position of the antenna unit 300 to ensure the shortest possible RF front-end signal path and optimal electromagnetic compatibility (EMC) performance.

[0075] As an example, in one embodiment, the chip 500 is mounted onto the chip mounting area 210B on the upper surface of the ceramic substrate island 210 using a surface mount process. Specifically, this step includes: cleaning the chip mounting area 210B of the ceramic substrate island 210 and applying a selected adhesive (such as conductive silver paste or thermally conductive adhesive); using a high-precision pick-and-place device and a vision system to accurately pick up the back side of the chip 500 and align it to the chip mounting area 210B, achieving a positive mounting position with the functional side facing up; performing a curing process, in which the adhesive is completely cured in a protective atmosphere at a temperature below 200°C to form an adhesive layer, thereby reducing thermal stress and thermal damage while achieving mechanical fixation and electrical connection between the chip 500 and the ceramic substrate island; and inspecting the mounting position, adhesive layer uniformity, and electrical performance using automated optical inspection (AOI) and other means to ensure packaging quality and reliability.

[0076] Step S13, wire bonding, electrically connecting the chip 500 to the antenna unit 300 via the first lead 510 and to the metal pin 220 via the second lead 520. For example... Figure 9 and Figure 10 As shown, where, Figure 9 This is a top view schematic diagram of wire bonding in a method for forming a packaging structure according to an embodiment of the present invention. Figure 10 It is along Figure 9 A schematic diagram of the cross-section along the A-A1 direction. Figure 10The first lead 510 and the feed line 320 are shown as dashed lines in the following figures. In this step, the chip 500 is electrically connected to the feed line 320 through the first lead 510.

[0077] The wire bonding uses the first wire 510 to achieve a high-precision electrical connection between a specific RF pad on the functional surface of the chip 500 and the feed line 320 of the antenna unit 300 already formed on the ceramic substrate island 210. Simultaneously, the second wire 520 is used to bond the other input / output, power and ground pads of the chip 500 to the corresponding metal pins 220, thereby constructing a complete internal electrical interconnection network.

[0078] In some embodiments, the first lead 510, due to its involvement in high-frequency signal transmission, requires the use of low-loss bonding wire (such as gold wire) and strict control of lead arc height, length, and loop shape to minimize parasitic inductance and impedance discontinuity. The second lead 520 may be selected from copper or gold wire with a thicker diameter depending on the current carrying requirements.

[0079] As an example, the specific steps of wire bonding further include: First solder joint bonding: The first lead 510 or the second lead 520 is guided to the pad of the chip 500 by a wedge (capillary or wedge tool), and ultrasonic energy, thermo-pressure, or thermo-ultrasonic energy is applied to form a metal-to-metal bond between the first lead 510 or the second lead 520 and the pad, completing the connection of the first solder joint. Wire arc forming: The bonding equipment controls the wedge to move along a preset path, pulling the first lead 510 or the second lead 520 into a specific arc (such as a fishhook shape or trapezoidal shape) to buffer stress and avoid the wire contacting the edge of the chip 500. Second solder joint bonding: The first lead 510 or the second lead 520 is led to the corresponding bonding area of ​​the metal pin 220 or the antenna unit 300, energy is applied again to form the second solder joint, and the wire tail is cut off by tearing or clamping. After bonding, non-destructive tensile testing and electrical continuity testing are required to ensure that all bonding points have sufficient mechanical strength and electrical continuity, thereby ensuring the reliability of signal transmission and the long-term stability of the packaging structure.

[0080] Step S14, molding, forming a molding compound 600, the molding compound 600 covering the lead frame 200, the antenna unit 300, the chip 500, the first lead 510 and the second lead 520, wherein the molding compound 600 does not cover the lower surface of the ceramic substrate island 210 and the lower surface of the metal pin 220. Figure 11 and Figure 12 As shown, where, Figure 11 This is a top view schematic diagram of the molding process in a method for forming a packaging structure according to an embodiment of the present invention. Figure 12 It is along Figure 11 A schematic diagram of the cross section along the A-A1 direction.

[0081] The molding compound 600 is made of epoxy molding compound (EMC) with low dielectric constant and high thermal conductivity, which is injected into a mold cavity and cured under specific temperature and pressure through a transfer molding process. The molding compound 600 provides robust mechanical protection and airtight environmental protection for the delicate internal chip 500, first lead 510, second lead 520 and antenna unit 300, effectively resisting moisture, dust and chemical corrosion.

[0082] The molding compound 600 does not cover the lower surface of the ceramic substrate island 210. The exposed lower surface of the ceramic substrate island 210 fully utilizes the high thermal conductivity of the ceramic material, establishing an efficient vertical heat dissipation path to the external heat sink for the heat generated during the operation of the chip 500, significantly reducing the junction temperature.

[0083] The molding compound 600 does not cover the lower surface of the metal leads 220. The exposed lower surface of the metal leads 220 ensures reliable electrical interconnection and mechanical fixation between the package structure and an external substrate, such as a printed circuit board (PCB), via solder. In some embodiments, the cross-section of the metal leads 220 is inverted trapezoidal or has a stepped structure, which can enhance the bonding force between the metal leads 220 and the molding compound 600, further avoid interface delamination, and improve the reliability of the package structure.

[0084] Furthermore, this step can significantly reduce the internal thermomechanical stress caused by temperature cycling by optimizing the matching of the thermal expansion coefficients between the molding compound and ceramic and metal materials, thereby comprehensively improving the long-term operational reliability, signal integrity and heat dissipation performance of the packaging structure.

[0085] Furthermore, in some embodiments, the lead frame 200 is divided into a plurality of frame units 201 by a dicing groove 204; after the step of molding to form a molded body 600, the process further includes: cutting along the dicing groove 204 to form a plurality of independent package structures, such that the sides of the metal leads 220 are exposed to the sides of the molded body 600. Figure 13 The diagram shows a cross-sectional view of the encapsulation structure formed in a method for forming an encapsulation structure according to an embodiment of the present invention. In the cutting step, a precise cutting process is used to cut the connecting rib structure 202 that connects the ceramic base island 210 to the outer frame 203 of the lead frame 200, as well as the metal pins 220 that connect adjacent frame units 201, thereby severing the connection between the ceramic base island 210 and the outer frame 203 of the lead frame 200, and the connection between adjacent frame units 201, thus forming an independent encapsulation structure.

[0086] Furthermore, in some embodiments, after molding, the forming method further includes the step of forming a thermally conductive layer 700 on the lower surface of the ceramic substrate island 210. For example... Figure 14 The diagram shown is a cross-sectional schematic of the formation of a thermally conductive layer 700 in a method for forming a packaging structure according to another embodiment of the present invention. The thermally conductive layer 700 covers at least a portion of the lower surface of the ceramic substrate island 210, and its thermal conductivity is greater than that of ceramic. Heat inside the packaging structure can be conducted through the ceramic substrate island 210 to the thermally conductive layer 700, and then dissipated through the thermally conductive layer 700. This efficiently conducts the heat generated by the chip 500 during operation to the external environment or an integrated microchannel heat sink, thereby improving the heat dissipation performance and reliability of the packaging structure. The thermally conductive layer 700 is formed by printing, coating, filling, or electroplating, and is in close contact with the lower surface of the ceramic substrate island 210 to reduce interfacial thermal resistance.

[0087] Furthermore, in some embodiments, the step of providing a lead frame 200 further includes: The lead frame 200 also includes a pre-molding layer 800 disposed between the ceramic substrate island 210 and the metal pin 220. Figure 15 The diagram shown is a cross-sectional view of the lead frame 200 in a method for forming a packaging structure according to another embodiment of the present invention. The pre-molding layer 800 fills and solidifies the gap between the ceramic base island 210 and the metal pin 220, firmly connecting the originally separate ceramic base island 210 and metal pin 220 into one unit, effectively enhancing the integrity and structural stability of the lead frame 200, and preventing the metal pin 220 from shifting or deforming due to external forces during subsequent transportation or processing.

[0088] The step of molding to form a molded body further includes: the molded body 600 further covering the surface of the pre-molded layer 800. For example... Figure 16 The diagram shown is a cross-sectional schematic of the molding process in a method for forming a packaging structure according to another embodiment of the present invention. During molding, the molding body 600 forms a tight physical bond with the surface of the pre-molding layer 800, thereby eliminating interface gaps between the two and enhancing the overall mechanical integrity, moisture resistance, sealing performance, and insulation reliability of the packaging structure.

[0089] Furthermore, in some embodiments, the forming method further includes the step of forming an electromagnetic shield 900, which electromagnetically isolates the antenna unit 300 from the chip 500.

[0090] The electromagnetic shielding cover 900, through its conductive continuity structure, forms an isolation barrier against electromagnetic waves radiated outward from the antenna unit 300 and interference signals intruding into the chip 500 from the outside, thereby significantly suppressing near-field coupling and far-field radiation interference between the antenna unit 300 and the chip 500, and improving the signal-to-noise ratio. The shielding cover can be made of materials such as copper, aluminum, or silver-plated ceramic through sputtering, electroplating, or pre-formed mounting. Its shielding effectiveness needs to be optimized according to the operating frequency band (such as the millimeter-wave band) to effectively block high-frequency crosstalk.

[0091] As an example, another embodiment of the present invention provides a method for forming an encapsulation structure having an electromagnetic shielding cover 900. The method includes: An electromagnetic shielding wall 910 is formed between the antenna mounting area 210A and the chip mounting area 210B of the ceramic substrate island 210. For example... Figure 17 The diagram shown is a top view of the formation of an electromagnetic shielding wall 910 in a method for forming a packaging structure according to another embodiment of the present invention. This step can be performed after the wire bonding step. The electromagnetic shielding wall 910 extends to the cleaving channel 204.

[0092] In some embodiments, the electromagnetic shielding wall 910 is made of a metal plate. The bottom of the metal plate is firmly attached to the upper surface of the ceramic substrate island 210 by an adhesive layer. Figure 18 As shown, it is a side view of the electromagnetic shielding wall 910 in the method of forming the packaging structure provided in another embodiment of the present invention. At the position corresponding to the first lead 510, the metal plate has a gap 911 so that the first lead 510 passes through the gap 911 to realize the electrical connection between the chip 500 and the antenna unit 300.

[0093] In one embodiment, the step of forming an electromagnetic shielding wall 910 between the antenna mounting area 210A and the chip mounting area 210B of the ceramic substrate island 210 further includes: the electromagnetic shielding wall 910 is composed of a plurality of metal pillars arranged at a predetermined interval. Figure 23The diagram shown is another top view of the electromagnetic shielding wall 910 formed in a packaging structure forming method according to another embodiment of the present invention. The metal pillars extend along a direction perpendicular to the ceramic substrate island 210, and their bottoms are attached to the upper surface of the ceramic substrate island 210 via an adhesive layer. Multiple metal pillars are spaced apart and distributed around the chip mounting area 210B. The first lead 510 passes through the gap between two adjacent metal pillars, realizing the electrical connection between the chip 500 and the antenna unit 300. The electromagnetic shielding wall 910 is composed of multiple metal pillars arranged at a set interval, meaning that multiple metal pillars are uniformly arranged at a fixed interval matching the wavelength of the electromagnetic wave to be shielded. The metal pillars are arranged regularly with consistent gaps, forming a continuous and sealed electromagnetic shielding barrier to effectively block electromagnetic waves of a specified frequency band. In one embodiment, the set interval is less than one-twentieth of the wavelength corresponding to the electromagnetic wave to be shielded.

[0094] The device is encapsulated to form an encapsulated body 600, which further covers the electromagnetic shielding wall 910, with the top surface of the electromagnetic shielding wall 910 exposed to the top surface of the encapsulated body 600. For example... Figure 19 and Figure 20 As shown, where, Figure 19 This is a top view schematic diagram of the molding process in the method for forming the packaging structure provided in another embodiment of the present invention. Figure 20 It is along Figure 19 A cross-sectional schematic diagram along the A-A1 direction. The top surface of the electromagnetic shielding wall 910 is exposed to the top surface of the encapsulated body 600 for subsequent contact and connection with the electromagnetic shielding layer 920 to form a closed electromagnetic shielding cover 900.

[0095] In one embodiment, the step of molding to form a molded body 600 further includes: performing a molding process to encapsulate the lead frame 200, the antenna unit 300, the chip 500, the first lead 510, the second lead 520, and the electromagnetic shielding wall 910 with a molding compound; and thinning the molding compound to expose the top surface of the electromagnetic shielding wall 910.

[0096] Following the step of molding and forming the molded body 600, the process further includes: forming an electromagnetic shielding layer 920 on the top surface and part of the side surfaces of the molded body 600; the electromagnetic shielding layer 920 is in contact with the top surface of the electromagnetic shielding wall 910 to form the electromagnetic shielding cover 900; and the chip 500 is located within the electromagnetic shielding cover 900. Figure 21 and Figure 22 As shown, where, Figure 21 This is a top view schematic diagram of the formation of the electromagnetic shielding layer 920 in the method for forming the packaging structure provided in another embodiment of the present invention. Figure 22 It is along Figure 21 A schematic diagram of the cross-section along the A-A1 direction. Figure 21 The electromagnetic shielding wall 910 is depicted using dashed lines. The electromagnetic shielding layer 920 covers the top surface and part of the side surfaces of the molding compound 600 and is in contact with the electromagnetic shielding wall 910, thereby forming the electromagnetic shielding cover 900. The electromagnetic shielding layer 920 also has a grounding area (not shown in the figure), which can be electrically connected to the grounding pads of structures such as printed circuit boards, or to the grounding pins in the metal pins 220, to achieve grounding of the electromagnetic shielding cover 900.

[0097] In some embodiments, the lead frame 200 is divided into a plurality of frame units 201 by the slit 204, and the step of forming the electromagnetic shield 920 is performed after the slit step. Specifically, multiple independent encapsulation structures are formed by slits along the slit 204 (see reference). Figure 13 In the step of cutting, the electromagnetic shielding wall 910 is cut simultaneously, and its side is exposed to the side of the encapsulated body 600. After the cutting step, an electromagnetic shielding layer 920 is formed on the top surface and part of the side surface of the encapsulated body 600.

[0098] In some embodiments, the step of forming an electromagnetic shielding layer 920 on the top surface and part of the side surfaces of the encapsulation 600 further includes: the electromagnetic shielding layer 920 being a metal plate, and the step of forming the electromagnetic shielding layer 920 further includes: the metal plate being adhered to the top surface and part of the side surfaces of the encapsulation 600 by an adhesive layer. Specifically, in one embodiment, a three-dimensional structure consisting of a top plate and side plates is pre-formed, and this three-dimensional structure is adhered to the top surface and part of the side surfaces of the encapsulation 600 by an adhesive layer. In another embodiment, the top plate and side plates are separate components, respectively adhered to the top surface and part of the side surfaces of the encapsulation 600 by adhesive layers, and the top plate and the side plates are in contact connection.

[0099] In some embodiments, the step of forming an electromagnetic shielding layer 920 on the top surface and part of the side surfaces of the molding compound 600 further includes: forming the electromagnetic shielding layer 920 on the top surface and part of the side surfaces of the molding compound 600 using physical or chemical processes. Specifically, the physical processes for forming the electromagnetic shielding layer 920 mainly include physical vapor deposition, such as magnetron sputtering; and hot pressing, which directly presses a pre-fabricated conductive polymer film onto the surface of the molding compound 600. Chemical processes include chemical plating and electrodeposition, which reduce and deposit metal ions on the surface of the molding compound 600 into a conductive layer through chemical reactions in a solution or an applied electric field.

[0100] The packaging structure formation method provided in this embodiment of the invention directly forms the antenna element 300 on the upper surface of the ceramic substrate island 210 (e.g., through direct patterning or screen printing), replacing the secondary integration of prefabricated antenna modules. This effectively simplifies the packaging process, eliminating the need for separate module manufacturing, procurement, handling, and assembly of the antenna element 300, thereby directly reducing material and manufacturing costs. Simultaneously, by eliminating the additional assembly interface between the antenna module and the substrate island, the accuracy deviation caused by the mismatch of thermal expansion coefficients of different components and accumulated tolerances is significantly reduced, achieving higher integration accuracy and stricter process tolerance control. Furthermore, the antenna element 300 and the chip 500 are directly connected on the same ceramic substrate island 210 via an extremely short first lead 510, constructing an ultra-short high-frequency signal transmission path, minimizing feed loss, and improving antenna efficiency and overall system RF performance. In addition, the packaging structure formation method provided in this embodiment of the invention fully utilizes the high thermal conductivity and excellent mechanical stability of the ceramic substrate island 210, not only enhancing the heat dissipation capacity of the packaging structure but also ensuring its long-term reliability under operating conditions such as thermal cycling.

[0101] The packaging structure formation method provided in this embodiment of the invention can form a QFN packaging structure, which can significantly reduce costs by replacing AIP packaging using a substrate, greatly improve the design flexibility and diversity of the chip 500, and has better performance than AIP using an organic substrate.

[0102] The packaging structure formation method provided in this invention forms a high-performance QFN (Quad Flat No-Lead) package structure. This package structure abandons the traditional AIP (Antenna in Package) technology path that relies on high-cost substrates (such as organic substrates) as antenna carriers, thereby significantly reducing material and process costs. This method allows the chip 500 to more flexibly design antenna modes and feed networks according to specific RF requirements, greatly improving design freedom and product diversification potential. Simultaneously, because the QFN lead frame has superior dielectric loss and thermal stability compared to organic substrates in the millimeter-wave band, its package structure performs better in key performance indicators such as insertion loss, heat dissipation efficiency, and frequency response, providing a cost-effective and high-performance hardware solution for high-frequency applications such as 5G millimeter-wave communication.

[0103] Based on the same inventive concept, embodiments of the present invention also provide a packaging structure manufactured using the above-described forming method. For example... Figures 2-13As shown, the packaging structure includes: a lead frame 200, including a ceramic substrate island 210 and metal pins 220 disposed around the ceramic substrate island 210; an antenna unit 300, forming an antenna mounting area 210A on the upper surface of the ceramic substrate island 210; a chip 500, mounted on a chip mounting area 210B on the upper surface of the ceramic substrate island 210, and electrically connected to the antenna unit 300 via a first lead 510, and electrically connected to the metal pins 220 via a second lead 520; and a molding compound 600, covering the lead frame 200, the antenna unit 300, the chip 500, the first lead 510, and the second lead 520, wherein the molding compound 600 does not cover the lower surface of the ceramic substrate island 210 and the lower surface of the metal pins 220.

[0104] The ceramic substrate 210 serves as the carrier for the chip 500 and the antenna unit 300. Its high dielectric constant significantly shortens the electromagnetic wave wavelength, enabling miniaturization of the packaging structure. Its low dielectric loss ensures high efficiency in high-frequency signal radiation and reduces energy loss. Excellent temperature stability minimizes the drift of the antenna resonant frequency with environmental changes, ensuring operational reliability. Furthermore, the ceramic substrate 210 possesses high thermal conductivity and excellent mechanical stability, enhancing the heat dissipation capacity of the packaging structure and guaranteeing its long-term reliability under thermal cycling and other operating conditions. In some embodiments, the ceramic substrate 210 is made of alumina (Al2O3), aluminum nitride (AlN), and silicon nitride (Si3N). 4） wait.

[0105] The ceramic substrate island 210 is divided into an antenna mounting area 210A and a chip mounting area 210B. The antenna element 300 is formed in the antenna mounting area 210A, and the chip 500 is disposed in the chip mounting area 210B. The ceramic substrate island 210 may include one or more independent antenna mounting areas 210A, and each antenna mounting area 210A may form one or more antenna elements 300. The ceramic substrate island 210 may include one or more independent chip mounting areas 210B, and the position of the chip mounting area 210B may be arranged according to the position of the antenna mounting area 210A.

[0106] The metal pins 220 are disposed around the ceramic substrate island 210. The upper surface of the pins 220 near the ceramic substrate island 210 is electrically connected to the input / output pads of the chip 500 via a second lead 520. The lower surface of the pins 220 away from the ceramic substrate island 210 serves as the external connection point for the final package structure. Furthermore, in some embodiments, the cross-section of the metal pins 220 is inverted trapezoidal or has a stepped structure to enhance its adhesion to the molding compound 600.

[0107] In some embodiments, the lead frame 200 includes a plurality of metal pins 220, which can be configured as a functional group including power pins, ground pins and signal pins, and can be electrically connected to the pads of different functions of the chip 500 via the second lead 520.

[0108] In some embodiments, the metal pins 220 are disposed around the chip mounting area 210B, thereby minimizing the linear spacing between the pads of the chip 500 and the bonding areas corresponding to the metal pins 220. This reduces the physical length of the second lead 520 connecting the chip 500 and the metal pins 220, enhancing the mechanical stability of the bonding points and improving their fatigue resistance under temperature cycling and mechanical vibration, thereby improving the reliability of the packaging structure in harsh environments.

[0109] The antenna unit 300 is disposed on the upper surface of the ceramic substrate island 210 to achieve efficient energy conversion between guided waves and free-space electromagnetic waves. Specifically, in the transmission path, the antenna unit 300 converts the high-frequency electrical signal processed by the chip 500 into electromagnetic waves and radiates them into space. In the receiving path, the antenna unit 300 captures electromagnetic waves in space and converts them into electrical signals, which are then fed into the chip 500 for processing. In this embodiment of the invention, the antenna unit 300 is fabricated directly on the ceramic substrate island 210. This directly reduces material and manufacturing costs, achieving higher integration precision and stricter process tolerance control. Furthermore, it fully utilizes the high thermal conductivity and excellent mechanical stability of the ceramic substrate island 210, enhancing the heat dissipation capacity of the packaging structure and ensuring its long-term reliability under operating conditions such as thermal cycling.

[0110] In some embodiments, the antenna unit 300 includes a radiating array 310 and a feed line 320 connected to the radiating array 310, and the chip 500 is electrically connected to the feed line 320 via the first lead 510. In this embodiment, the radiating array 310 is illustrated by way of a 2x2 configuration; however, the design of this package structure has inherent scalability and flexibility. The size, scale, and arrangement of the radiating array 310 can be customized according to specific system requirements, target frequency bands, and radiation characteristics. For example, it can be expanded to a larger array of MxN (M and N are both positive integers) to improve gain and directivity, or adjusted to an asymmetric arrangement to achieve specific beamforming. This configurability ensures that the package can adapt to diverse antenna performance requirements, from narrowband high gain to broadband scanning.

[0111] In some embodiments, since the radiating array 310 and the power supply circuit are fabricated in the same step, the radiating array 310 and the power supply line 320 are located on the same layer in the package structure.

[0112] In some embodiments, the packaging structure includes at least one receiving antenna unit and at least one transmitting antenna unit to enable full-duplex communication. In this embodiment, the packaging structure includes one receiving antenna unit and one transmitting antenna unit as an example.

[0113] In some embodiments, the receiving antenna unit and the transmitting antenna unit are arranged diagonally opposite each other on the ceramic base island 210, so as to maximize the distance between the receiving antenna unit and the transmitting antenna unit by utilizing the diagonal distance of the ceramic base island 210, so as to effectively suppress near-field coupling and far-field interference between the receiving antenna unit and the transmitting antenna unit.

[0114] The chip 500 is disposed in the chip mounting area 210B on the upper surface of the ceramic substrate island 210, and is mounted on the upper surface of the ceramic substrate island 210 via an adhesive layer. The chip includes a functional side and a back side. The back side of the chip 500 is mounted on the upper surface of the ceramic substrate island 210 via an adhesive layer, and the functional side of the chip 500 faces away from the ceramic substrate island 210. The chip 500 can be a millimeter-wave chip, an RF front-end chip, a power amplifier, or a low-noise amplifier. The heat generated by the chip 500 is efficiently conducted to the ceramic substrate island 210, which has a high thermal conductivity, through the thermal interface material between the back side and the ceramic substrate island 210. Simultaneously, the upward orientation of the functional side provides a convenient process interface for electrical connection with the antenna unit 300 and the metal pin 220 via the first lead 510 and the second lead 520.

[0115] The chip 500 is electrically connected to the antenna unit 300 via a first lead 510 and to the metal pin 220 via a second lead 520. In some embodiments, the first lead 510, due to its involvement in high-frequency signal transmission, requires the use of low-loss bonding wire (such as gold wire) and strict control over the lead arc height, length, and loop shape to minimize parasitic inductance and impedance discontinuities. The second lead 520 may be selected using copper or gold wire with a thicker diameter, depending on the current carrying requirements.

[0116] The molding compound 600 encapsulates the lead frame 200, the antenna unit 300, the chip 500, the first lead 510, and the second lead 520. The molding compound 600 provides robust mechanical and hermetically sealed protection for the chip 500, the first lead 510, the second lead 520, and the antenna unit 300, effectively resisting moisture, dust, and chemical corrosion. The molding compound 600 does not cover the lower surface of the ceramic substrate island 210, establishing an efficient vertical heat dissipation path for the heat generated by the chip 500 during operation, significantly reducing junction temperature. The molding compound 600 does not cover the lower surface of the metal pins 220, ensuring reliable electrical interconnection and mechanical fixation between the package structure and the external substrate via solder.

[0117] In some embodiments, the packaging structure further includes a thermally conductive layer 700 disposed on the lower surface of the ceramic substrate island 210, as shown in the reference. Figure 14 As shown. The thermally conductive layer 700 covers all or part of the lower surface of the ceramic substrate island 210. Its thermal conductivity is greater than that of ceramic. The heat inside the packaging structure can be conducted through the ceramic substrate island 210 to the thermally conductive layer 700, and then dissipated through the thermally conductive layer 700. This efficiently conducts the heat generated by the chip 500 during operation to the external environment or an integrated microchannel heat sink, thereby improving the heat dissipation performance and reliability of the packaging structure.

[0118] In some embodiments, the packaging structure further includes a pre-molding layer 800 disposed between the ceramic substrate island 210 and the metal pins 220, and the molding compound 600 further covers the surface of the pre-molding layer 800. (See reference...) Figure 16 As shown. The pre-molded layer 800 fills and cures the gap between the ceramic substrate island 210 and the metal pin 220, firmly connecting the originally separate ceramic substrate island 210 and metal pin 220 into one, effectively enhancing the integrity and structural stability of the packaging structure.

[0119] In one embodiment, the packaging structure further includes an electromagnetic shielding cover 900, within which the chip 500 is located. The electromagnetic shielding cover 900 includes: an electromagnetic shielding wall 910 disposed between the antenna mounting area 210A and the chip mounting area 210B of the ceramic substrate island 210; the molding compound 600 further covers the electromagnetic shielding wall 910, with the top surface of the electromagnetic shielding wall 910 exposed to the top surface of the molding compound 600; and an electromagnetic shielding layer 920 disposed on the top surface and part of the side surfaces of the molding compound 600, and in contact with the top surface of the electromagnetic shielding wall 910. (See reference...) Figures 17-22 .

[0120] The electromagnetic shield 900 forms an isolation barrier for the electromagnetic waves radiated outward by the antenna unit 300 and the interference signals intruding into the chip 500 from the outside through its conductive continuity structure, thereby significantly suppressing the near-field coupling and far-field radiation interference between the antenna unit 300 and the chip 500 and improving the signal-to-noise ratio.

[0121] In some embodiments, the electromagnetic shielding wall 910 is made of a metal plate, the bottom of which is firmly attached to the upper surface of the ceramic substrate island 210 by an adhesive layer, and the top of which is exposed to the molding compound 600. A gap is provided at the location of the first lead 510, through which the first lead 510 passes to achieve electrical connection between the chip 500 and the antenna unit 300. (See reference...) Figure 17 and Figure 18 .

[0122] In some embodiments, the electromagnetic shielding wall 910 is composed of a plurality of metal pillars arranged at a predetermined interval, and the first lead 510 passes through the gap between two adjacent metal pillars. The metal pillars extend in a direction perpendicular to the ceramic substrate island 210, with their bottoms attached to the upper surface of the ceramic substrate island 210 via an adhesive layer, and their tops exposed to the molding compound 600. The plurality of metal pillars are arranged at intervals and distributed around the periphery of the chip mounting area 210B, and the first lead 510 passes through the gap between two adjacent metal pillars to achieve electrical connection between the chip 500 and the antenna unit 300. (See reference...) Figure 23 .

[0123] The electromagnetic shielding layer 920 covers the top surface and part of the side surface of the molding compound 600 and is in contact with the electromagnetic shielding wall 910, thereby forming the electromagnetic shielding cover 900. The electromagnetic shielding layer 920 also has a grounding area (not shown in the figure), which can be electrically connected to the grounding pad of the printed circuit board or other structure, or to the grounding pin in the metal pin 220, so as to realize the grounding of the electromagnetic shielding cover 900.

[0124] In some embodiments, the electromagnetic shielding layer 920 is a metal plate, and the electromagnetic shielding layer 920 is adhered to the top surface and part of the side surface of the encapsulation body 600 by an adhesive layer. Specifically, in one embodiment, a three-dimensional structure consisting of a top plate and a side plate is pre-formed, and this three-dimensional structure is adhered to the top surface and part of the side surface of the encapsulation body 600 by an adhesive layer. In another embodiment, the top plate and the side plate are separate components, respectively adhered to the top surface and part of the side surface of the encapsulation body 600 by an adhesive layer, and the top plate and the side plate are in contact connection.

[0125] In one embodiment, the electromagnetic shielding layer 920 is formed on the top surface and part of the side surface of the molded body 600 by electroplating or sputtering process, that is, the electromagnetic shielding layer 920 is directly formed on the top surface and part of the side surface of the molded body 600 without the need for adhesive layer bonding.

[0126] In one embodiment, the side of the metal pin 220 is exposed to the side of the molding compound 600 to increase the area of ​​the metal pin 220 for external connection, thereby improving the reliability of the electrical connection of the package structure.

[0127] The packaging structure provided by this invention effectively simplifies the packaging process, eliminating the need for separate module manufacturing, procurement, handling, and assembly of antenna elements, thereby directly reducing material and manufacturing costs. Simultaneously, it significantly reduces accuracy deviations caused by mismatched thermal expansion coefficients and accumulated tolerances among different components, achieving higher integration accuracy and stricter process tolerance control. Furthermore, it constructs an ultra-short high-frequency signal transmission path, minimizing feed loss and improving antenna efficiency and overall system RF performance. In addition, it fully utilizes the high thermal conductivity and excellent mechanical stability of the ceramic substrate island, enhancing the heat dissipation capacity of the packaging structure and ensuring its long-term reliability under operating conditions such as thermal cycling.

[0128] It should be noted that references to "an embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0129] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data used interchangeably where appropriate. Furthermore, embodiments and features within embodiments of this invention can be combined with each other unless otherwise specified. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0130] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for forming an encapsulation structure, characterized in that, include: A lead frame is provided, the lead frame including a frame unit, the frame unit including a ceramic substrate island and metal pins disposed around the ceramic substrate island; An antenna element is formed in the antenna mounting area on the upper surface of the ceramic substrate island; A chip is mounted on the chip mounting area on the upper surface of the ceramic substrate island; Wire bonding connects the chip to the antenna unit via a first lead and to the metal pin via a second lead. Molding is performed to form a molded body that encapsulates the lead frame, the antenna unit, the chip, the first lead, and the second lead, wherein the molded body does not cover the lower surface of the ceramic substrate island and the lower surface of the metal pins.

2. The method for forming the packaging structure according to claim 1, characterized in that, The step of providing a lead frame further includes: the metal pins being disposed around the periphery of the chip mounting area.

3. The method for forming the packaging structure according to claim 1, characterized in that, The step of forming an antenna element in the antenna placement area on the upper surface of the ceramic substrate island further includes: forming a metal layer in the antenna placement area on the upper surface of the ceramic substrate island; and patterning the metal layer to form the antenna element.

4. The method for forming the packaging structure according to claim 3, characterized in that, The step of forming a metal layer in the antenna mounting area on the upper surface of the ceramic substrate island further includes: forming the metal layer using a direct copper plating process, or forming the metal layer using a direct copper cladding process, or forming the metal layer using an active metal brazing process.

5. The method for forming the packaging structure according to claim 1, characterized in that, The step of forming an antenna element in the antenna mounting area on the surface of the ceramic substrate island further includes: forming the antenna element on the surface of the ceramic substrate island using a screen printing process.

6. The method for forming the packaging structure according to claim 1, characterized in that, The step of forming an antenna unit in the antenna setting area on the upper surface of the ceramic substrate island further includes: the antenna unit includes a radiating array and a feed line connected to the radiating array; the wire bonding step further includes: the chip is electrically connected to the feed line through the first lead.

7. The method for forming the packaging structure according to claim 1, characterized in that, The step of forming an antenna unit in the antenna mounting area on the surface of the ceramic substrate island further includes: forming at least one receiving antenna unit and at least one transmitting antenna unit on the surface of the ceramic substrate island.

8. The method for forming the packaging structure according to claim 7, characterized in that, The step of forming at least one receiving antenna unit and at least one transmitting antenna unit on the upper surface of the ceramic substrate island further includes: the receiving antenna unit and the transmitting antenna unit are disposed opposite each other on the ceramic substrate island.

9. The method for forming the packaging structure according to claim 1, characterized in that, The step of mounting the chip in the chip mounting area on the surface of the ceramic substrate island further includes: mounting the chip in the chip mounting area on the surface of the ceramic substrate island using a surface mount process.

10. The method for forming the packaging structure according to claim 1, characterized in that, The step of providing a lead frame further includes: the lead frame further includes a pre-molding layer disposed between the ceramic substrate island and the metal pin; the step of molding to form a molded body further includes: the molded body further covering the surface of the pre-molding layer.

11. The method for forming the packaging structure according to claim 1, characterized in that, It also includes the following step: forming a thermally conductive layer on the lower surface of the ceramic substrate island.

12. The method for forming the packaging structure according to claim 1, characterized in that, It also includes the following steps: forming an electromagnetic shield, which electromagnetically isolates the antenna unit from the chip.

13. The method for forming the packaging structure according to claim 12, characterized in that, The step of forming an electromagnetic shielding cover further includes: forming an electromagnetic shielding wall between the antenna placement area and the chip mounting area of ​​the ceramic substrate island; molding, the step of forming a molding body further includes: the molding body further covers the electromagnetic shielding wall, and the top surface of the electromagnetic shielding wall is exposed on the top surface of the molding body; molding, the step of forming a molding body further includes: forming an electromagnetic shielding layer on the top surface and part of the side surface of the molding body, the electromagnetic shielding layer being in contact with the top surface of the electromagnetic shielding wall to form the electromagnetic shielding cover, and the chip being located inside the electromagnetic shielding cover.

14. The method for forming the packaging structure according to claim 13, characterized in that, The step of forming an electromagnetic shielding wall between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island further includes: the electromagnetic shielding wall is made of a metal plate and has a gap at the first lead position, through which the first lead passes.

15. The method for forming the packaging structure according to claim 13, characterized in that, The step of forming an electromagnetic shielding wall between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island further includes: the electromagnetic shielding wall is composed of a plurality of metal pillars arranged at a set interval, and the first lead passes through the gap between two adjacent metal pillars.

16. The method for forming the packaging structure according to claim 13, characterized in that, The step of forming an electromagnetic shielding layer on the top surface and part of the side surface of the encapsulated body further includes: the electromagnetic shielding layer is a metal plate, and the step of forming the electromagnetic shielding layer further includes: the metal plate is attached to the top surface and part of the side surface of the encapsulated body by an adhesive layer.

17. The method for forming the packaging structure according to claim 13, characterized in that, The step of forming an electromagnetic shielding layer on the top surface and part of the side surface of the molded body further includes: forming the electromagnetic shielding layer on the top surface and part of the side surface of the molded body using physical or chemical processes.

18. The method for forming the packaging structure according to claim 1, characterized in that, The step of providing a lead frame further includes: the lead frame being divided into a plurality of frame units by a slit; The step of forming the molded enclosure further includes cutting along the dicing groove to form multiple independent package structures, such that the sides of the metal pins are exposed to the sides of the molded enclosure.

19. A packaging structure, characterized in that, include: A lead frame, comprising a ceramic substrate island and metal pins disposed around the periphery of the ceramic substrate island; Antenna element, formed in the antenna mounting area on the upper surface of the ceramic substrate island; The chip is mounted on the chip mounting area on the upper surface of the ceramic substrate island and is electrically connected to the antenna unit through a first lead and to the metal pin through a second lead. A molding compound encapsulates the lead frame, the antenna unit, the chip, the first lead, and the second lead, wherein the molding compound does not cover the lower surface of the ceramic substrate island or the lower surface of the metal pins.

20. The packaging structure according to claim 19, characterized in that, The metal pins are located around the chip mounting area.

21. The packaging structure according to claim 19, characterized in that, The antenna unit includes a radiating array and a feed line connected to the radiating array, and the chip is electrically connected to the feed line through the first lead.

22. The packaging structure according to claim 21, characterized in that, The radiating array and the feed line are located on the same layer.

23. The packaging structure according to claim 19, characterized in that, The packaging structure includes at least one receiving antenna unit and at least one transmitting antenna unit.

24. The packaging structure according to claim 23, characterized in that, The receiving antenna unit and the transmitting antenna unit are arranged diagonally opposite each other on the ceramic substrate island.

25. The packaging structure according to claim 19, characterized in that, The chip is attached to the surface of the ceramic substrate island via an adhesive layer.

26. The packaging structure according to claim 19, characterized in that, It also includes a pre-molded layer disposed between the ceramic substrate island and the metal pin, and the molding compound further covers the surface of the pre-molded layer.

27. The packaging structure according to claim 19, characterized in that, It also includes a thermally conductive layer disposed on the lower surface of the ceramic substrate island.

28. The packaging structure according to claim 19, characterized in that, It also includes an electromagnetic shielding cover, within which the chip is located. The electromagnetic shielding cover includes: An electromagnetic shielding wall is disposed between the antenna mounting area and the chip mounting area of ​​the ceramic substrate island. The molding compound also covers the electromagnetic shielding wall, and the top surface of the electromagnetic shielding wall is exposed to the top surface of the molding compound. An electromagnetic shielding layer is disposed on the top surface and part of the side surface of the encapsulated body, and is in contact with and connected to the top surface of the electromagnetic shielding wall.

29. The packaging structure according to claim 28, characterized in that, The electromagnetic shielding wall is made of a metal plate and has a gap at the position of the first lead wire, through which the first lead wire passes.

30. The packaging structure according to claim 28, characterized in that, The electromagnetic shielding wall is composed of multiple metal pillars arranged at a set interval, and the first lead passes through the gap between two adjacent metal pillars.

31. The packaging structure according to claim 28, characterized in that, The electromagnetic shielding layer is attached to the top surface and part of the side surface of the plastic encapsulation through an adhesive layer.

32. The packaging structure according to claim 19, characterized in that, The sides of the metal pins are exposed to the sides of the molding compound.

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