A packaging structure for a fully encapsulated antenna and its manufacturing process

Abstract

The present invention discloses a packaging structure for a fully encapsulated antenna, including a redistribution layer, a molding compound layer disposed on one surface of the redistribution layer, and solder balls disposed on the other surface of the redistribution layer. An antenna and a device connected to contacts on the redistribution layer are simultaneously encapsulated in the molding compound layer, and the antenna is completely encapsulated within the molding compound body. The present invention also discloses a preparation process for such a packaging structure of a fully encapsulated antenna. First, a redistribution layer is fabricated on a temporary carrier using a thin-film process, and then an antenna structure is fabricated on the redistribution layer using dry-film lithography and electroplating methods. Immediately afterwards, a chip is also mounted on the redistribution layer, and it and the antenna structure are encapsulated together within the molding compound body. By adopting the design solution of the present invention, the area of the package is smaller, more compact, and the thickness is thinner; the entire structure of the antenna is fabricated using lithography methods, so the dimensions of the antenna structure can be controlled very precisely with high precision.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and particularly to a packaging structure for a fully encapsulated antenna and a preparation process therefor. Background Art

[0002] With the advent of the 5G mobile communication era, the demand for heterogeneous integrated radio frequency front-end modules is increasing day by day. In the evolution of antenna packaging technology, the integration of radio frequency chip components and antennas has become a new trend. Therefore, the AiP (Antenna in Package) packaging technology has gradually become the focus of attention in the advanced packaging industry.

[0003] Currently, in the existing fan-out antenna packaging, most are formed on the surface of a plastic package body (including passive components and bare wafers, etc.) with a chip encapsulated, including the upper surface or the lower surface of the plastic package body, using a method for manufacturing a redistribution layer (Re-Distribution Layer, that is, RDL) to form an antenna layer, or the antenna layer is respectively located on the surfaces of the plastic package body and the PCB packaging substrate. In this type of packaging method, the antenna layer structure needs to additionally occupy the area originally used for arranging RDL traces on the surface of the plastic package body, or occupy the area on the PCB surface, thus imposing certain limitations on the design and manufacturing process of the overall packaging traces. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to solve the problem that the existing fan-out antenna packaging arranges the antenna on the upper and lower surfaces of the plastic package body, occupying more trace areas and at the same time increasing the overall thickness of the PCB.

[0005] Technical Solution: To solve the above problems, the present invention provides the following technical solutions:

[0006] A packaging structure for a fully encapsulated antenna, including at least one redistribution layer, a plastic package layer provided on one side surface of the redistribution layer, and solder balls provided on the other side surface of the redistribution layer. The antenna and devices connected to the metal contacts on the redistribution layer are simultaneously encapsulated in the plastic package layer, and the antenna is completely encapsulated within the plastic package layer.

[0007] The existing antenna structures are generally arranged on the upper and lower surfaces of the plastic package body or the substrate. The antennas in the prior art are for electromagnetic waves with longer wavelengths, so the size of the antennas is relatively large, and a relatively large area and region are required to simulate the antenna structure.

[0008] Furthermore, with the continuous progress of technology and the advent of the 5G era, by using electromagnetic waves with shorter wavelengths (millimeter waves), we can consider setting up the antenna in other ways. The present invention proposes to completely encapsulate the antenna without affecting the realization of its own functions, liberating the wiring space on the surface or the upper and lower surfaces of the encapsulation body, and at the same time reducing the overall thickness of the package and further improving the integration level.

[0009] In the technical solution of this application, if the antenna is completely encapsulated and flush with the upper and lower surfaces, the exposed antenna contacts will still conflict with the wiring on the surface of the encapsulation body.

[0010] Furthermore, the antenna includes an independent antenna conductor and a ground reflection conductor, and the ground reflection conductor is arranged between the antenna conductor and the device. The antenna conductor is electrically connected to the signal metal contact on the redistribution layer, and the ground reflection conductor is electrically connected to the ground metal contact on the redistribution layer.

[0011] Furthermore, both the ground reflection conductor and the antenna conductor are made of copper metal. The ground reflection conductor is arranged between the antenna conductor and the chip, preventing signal interference between the antenna signal and the device.

[0012] Furthermore, the redistribution layer includes a dielectric layer and metal interconnect layers penetrating the dielectric layer.

[0013] Furthermore, the device includes a chip and passive components.

[0014] Furthermore, both the antenna conductor and the ground reflection conductor are laid out flat on the redistribution layer and completely encapsulated by the encapsulation layer to form a patterned antenna.

[0015] Since the antenna itself has a certain area or volume, the prior art adopts a technical solution that occupies more volume and occupies more area on both the upper and lower surfaces of the encapsulation body through the encapsulation body. By adopting the technical solution of the present invention, by dividing the antenna into an independent antenna conductor and a ground reflection conductor, the antenna can be designed as a patterned antenna while retaining the realization of the functions of the antenna itself.

[0016] A preparation process for the encapsulation structure of the completely encapsulated antenna described above includes the following steps:

[0017] 1) Adhere a temporary bonding adhesive layer on the surface of the temporary carrier wafer;

[0018] 2) Fabricate a redistribution layer on the surface of the temporary bonding adhesive layer using a thin film process;

[0019] 3) On the redistribution layer, fabricate the antenna using the methods of dry film lithography and electroplating;

[0020] 4) Then, continue to attach the devices to be encapsulated in the area of the rewiring layer where the antenna structure is not fabricated;

[0021] 5) Integrally encapsulate the antenna and devices on the rewiring layer to form an encapsulation layer, so that both the antenna structure and the chip are completely embedded in the encapsulation body;

[0022] 6) Use laser or thermal peeling to separate the temporary carrier from the rewiring layer thereon, and remove the temporary bonding adhesive, so as to expose the other side of the rewiring layer opposite to the side where the encapsulation layer is located;

[0023] 7) Ball grid array (BGA) is implanted on the rewiring layer and the soldering of the solder balls is completed;

[0024] 8) Cut the encapsulated devices into individual encapsulated body units.

[0025] Further, in step 2), the upper and lower surfaces of the metal interconnection layer are at least flush with the upper and lower surfaces of the dielectric layer, and the exposed ends of the metal interconnection layer serve as metal contacts.

[0026] Further, the device includes a chip and passive components. When mounted, the device side of the chip faces the rewiring layer, and the metal bumps of the device are connected to the corresponding metal contacts on the rewiring layer.

[0027] Beneficial effects: Compared with the prior art, the present invention:

[0028] The present invention adopts the method of first fabricating the rewiring layer and then encapsulating the components to form the encapsulation layer, which can effectively improve the accuracy and reliability of the rewiring layer. Moreover, the patterned antenna structure is wrapped in the encapsulation body, without occupying the area of the upper or lower surface of the encapsulation body, that is, without occupying the wiring space of the rewiring layer on the surface of the encapsulation body. Thus, the area of the rewiring layer can be effectively reduced, and further the encapsulation volume can be reduced, the integration degree of the encapsulated device can be improved, and the flexibility of the design and fabrication of the rewiring layer is increased. Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of the product of Embodiment 1 of the present invention;

[0030] Figure 2 is a first example of the patterned antenna of Embodiment 1 of the present invention;

[0031] Figure 3 is a second example of the patterned antenna of Embodiment 1 of the present invention;

[0032] Figure 4 is a schematic structural diagram of the product of Embodiment 2 of the present invention;

[0033] Figure 5Schematic diagram of step 1) of Embodiment 3 of the present invention;

[0034] Figure 6 Schematic diagram of step 2) of Embodiment 3 of the present invention;

[0035] Figure 7 Schematic diagram of step 3) of Embodiment 3 of the present invention;

[0036] Figure 8 Schematic diagram of step 4) of Embodiment 3 of the present invention;

[0037] Figure 9 Schematic diagram of step 5) of Embodiment 3 of the present invention;

[0038] Figure 10 Schematic diagram of step 6) of Embodiment 3 of the present invention;

[0039] Figure 11 Schematic diagram of step 7) of Embodiment 3 of the present invention. Detailed implementation manners

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] Embodiment 1: As Figures 1 to 3 shown, a packaging structure of a fully encapsulated antenna includes at least one rewiring layer 120, a molding layer 160 disposed on one side surface of the rewiring layer 120, and solder balls 170 disposed on the other side surface of the rewiring layer 120. The antenna 130 and the device connected to the metal contacts on the rewiring layer 120 are simultaneously encapsulated in the molding layer 160, and the antenna 130 is completely encapsulated in the molding layer 160.

[0042] The existing antenna structures are generally disposed on the upper and lower surfaces of the molding body or the substrate. The antennas in the prior art are for electromagnetic waves with longer wavelengths, so the sizes of the antennas are relatively large, and a relatively large area and region are required to simulate the antenna structures. With the continuous progress of technology, with the advent of the 5G era, we can consider setting the antennas in other ways by using electromagnetic waves with shorter wavelengths (millimeter waves). The present invention proposes to completely encapsulate the antennas without affecting the realization of the functions of the antennas themselves, liberating the routing space on the surface of the molding body or the upper and lower surfaces of the substrate, and at the same time being able to reduce the overall thickness of the package and further improve the integration level.

[0043] In the technical solution of the present application, if the antenna is completely encapsulated and flush with the upper and lower surfaces, the exposed antenna contacts will still conflict with the traces on the surface of the molding body.

[0044] The antenna 130 includes an independent antenna conductor 131 and a ground reflection conductor 132. The ground reflection conductor 132 is disposed between the antenna conductor 131 and the device. The antenna conductor 131 is electrically connected to the signal metal contact on the rewiring layer 120, and the ground reflection conductor 132 is electrically connected to the ground metal contact on the rewiring layer 120.

[0045] Both the ground reflection conductor and the antenna conductor are made of copper. The antenna conductor is placed near the outside in the plastic package, while the ground reflection conductor is disposed between the antenna conductor and the chip. This not only ensures the signal transmission performance of the antenna conductor but also prevents signal interference between the antenna signal and the chip.

[0046] The rewiring layer 120 includes a dielectric layer 121 and a metal interconnection layer 122 penetrating the dielectric layer 121.

[0047] The device includes a chip 140 and a passive component 150.

[0048] Both the antenna conductor 131 and the ground reflection conductor 132 are laid flat on the rewiring layer 120 and completely encapsulated by the encapsulation layer 160 to form a patterned antenna.

[0049] Since the antenna itself has a certain area or volume, the prior art adopts a technical solution that occupies more volume and occupies more area on both the upper and lower surfaces of the plastic package through the plastic package. However, by adopting the technical solution of the present invention, by dividing the antenna into an independent antenna conductor and a ground reflection conductor, the antenna can be designed as a patterned antenna while retaining the realization of the functions of the antenna itself.

[0050] Embodiment 2: As Figure 4 shown, based on Embodiment 1, Embodiment 2 is proposed. Multilayer encapsulation is performed on the basis of Embodiment 1, that is, it includes more than two rewiring layers. Taking two rewiring layers as an example, the stacking order is solder balls, the first rewiring layer, the first encapsulation layer, the second rewiring layer, and the second encapsulation layer.

[0051] Since a patterned antenna is adopted in the first encapsulation layer, only metal interconnection posts 180 are required for electrical connection between the first rewiring layer and the second rewiring layer, enabling the second rewiring layer to perform more metal contact interconnections through the metal interconnection posts 180 at the position where the antenna originally needed to be led out, improving the integration accuracy.

[0052] Embodiment 3: A manufacturing process of a packaging structure of a fully encapsulated antenna, including the following steps:

[0053] 1) Apply a temporary bonding adhesive 110 on a temporary carrier 100. The material of the temporary carrier can be a silicon wafer, ceramic, glass, quartz, etc. As Figure 5as shown

[0054] 2) A redistribution layer 120 is fabricated on the wafer with the temporary bonding adhesive 110 by a thin film process. The redistribution layer is composed of a dielectric layer 121 and a metal interconnect layer 122.

[0055] The dielectric layer 121 is usually an inorganic dielectric material (such as silicon oxide, silicon nitride, etc.) or an organic dielectric material (such as polyimide, resin, etc.). Preferably, the polyimide organic dielectric material is selected in the present invention. The dielectric layer film is fabricated by a spin coating method, and photolithography is performed on the polyimide dielectric layer to form the required pattern;

[0056] The material of the metal interconnect layer 122 is usually copper, titanium, tin, etc. Preferably, the metal conductive material selected in the present invention is copper (with a little titanium as the copper underlayer under the copper), which is fabricated by physical vapor deposition (PVD) and electroplating (ECD) methods, and the required metal interconnect wiring pattern is photolithographed.

[0057] According to the actual routing requirements, the metal interconnect layer 122 can be one layer or multiple layers, and together with the dielectric layer 121, it constitutes the redistribution layer structure 120. As Figure 6 shown

[0058] 3) An antenna 130 is continuously fabricated on the redistribution layer; the antenna 130 includes an antenna conductor 131 and a ground reflection conductor layer 132, as Figure 7 shown

[0059] 4) Devices are attached to the area on the redistribution layer where the antenna structure is not fabricated. The attached devices include a chip 140 (i.e., a bare die with metal bumps, such as an RF chip) or a passive component 150; the metal bumps of the chip 140 or the passive component 150 correspond one by one to the corresponding metal contact positions on the redistribution layer, and reliable circuit interconnection is formed between the two by adding solder paste and reflow strengthening. As Figure 8 shown

[0060] 5) The antenna fabricated on the redistribution layer and the attached devices are encapsulated to form an encapsulation layer 160, as Figure 9 shown. The antenna and the devices are both embedded in the encapsulation layer, where the height of the antenna is slightly greater than the thickness of the devices, and the height difference between the two is about 50 - 150 um.

[0061] 6) The temporary bonding wafer 100 is removed by a laser or thermal stripping method, and the temporary bonding adhesive 110 is removed to expose the metal contacts on the other side of the redistribution layer relative to the side where the encapsulation layer is located; as Figure 10 shown

[0062] 7) Solder balls 170 are planted on the metal contacts of the rewiring layer and then cured by reflow soldering; as Figure 11 shown.

[0063] After the above process steps are completed, the formed wafer-type fan-out package is subjected to unit cutting to form independent packaged devices.

Claims

1. A packaging structure for a fully encapsulated antenna, comprising at least one rewiring layer, a molding layer disposed on one side surface of the rewiring layer, and solder balls disposed on the other side surface of the rewiring layer, characterized in that: An antenna and a device connected to metal contacts on a redistribution layer are encapsulated in the encapsulation layer at the same time, and the antenna is completely encapsulated within the encapsulation layer; The preparation process of the encapsulation structure for completely encapsulating the antenna includes the following steps: 1) Adhere a temporary bonding adhesive layer on the surface of the temporary carrier wafer; 2) Fabricate a redistribution layer on the surface of the temporary bonding adhesive layer by a thin film process; 3) On the redistribution layer, fabricate an antenna by using the method of dry film lithography and electroplating; 4) Then attach the device to be encapsulated in the area of the redistribution layer where the antenna structure is not fabricated; 5) Integrally encapsulate the antenna and the device on the redistribution layer to form an encapsulation layer, so that the antenna structure and the chip are both completely embedded in the encapsulation body; 6) Separate the temporary carrier wafer from the redistribution layer thereon by using laser or thermal peeling, and remove the temporary bonding adhesive, so that the other side of the redistribution layer opposite to the side where the encapsulation layer is located is exposed; 7) Ball mounting is performed on the redistribution layer and the solder balls are welded; 8) The encapsulated device is diced into individual encapsulated body units.

2. The encapsulation structure of the fully encapsulated antenna according to claim 1, wherein: The antenna includes independent antenna conductors and a ground reflection conductor, and the ground reflection conductor is arranged between the antenna conductor and the device. The antenna conductor is electrically connected to the signal metal contacts on the redistribution layer, and the ground reflection conductor is electrically connected to the ground metal contacts on the redistribution layer.

3. The encapsulation structure of the fully encapsulated antenna according to claim 1, wherein: The redistribution layer includes a dielectric layer and metal interconnect layers penetrating the dielectric layer.

4. The encapsulation structure of the fully encapsulated antenna according to claim 1, characterized in that: The device includes a chip and passive components.

5. The encapsulation structure of the fully encapsulated antenna according to claim 2, characterized in that: The antenna conductor and the ground reflection conductor are both laid out flat on the redistribution layer and completely encapsulated by the encapsulation layer to form a patterned antenna.

6. The encapsulation structure of the fully encapsulated antenna according to claim 3, characterized in that: In the step 2), the upper and lower surfaces of the metal interconnect layer are at least flush with the upper and lower surfaces of the dielectric layer, and the exposed ends of the metal interconnect layer serve as metal contacts.

7. The encapsulation structure of the fully encapsulated antenna according to claim 1, characterized in that: The device includes a chip and passive components. When mounted, the device surface of the chip faces the redistribution layer, and the metal bumps of the chip are connected to the corresponding metal contacts on the redistribution layer.

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