Radio frequency microsystem based on wave-absorbing shielding structure

Abstract

The present application relates to a kind of radio frequency microsystem based on wave-absorbing shielding structure, comprising: radiation source, it is configured to produce electromagnetic radiation;And wave-absorbing shielding structure, it is configured to absorb and shield electromagnetic radiation produced by the radiation source, wherein the wave-absorbing shielding structure includes: electromagnetic material layer, it is configured to absorb electromagnetic radiation;Resonant cavity, it is configured to absorb electromagnetic radiation;Conformal shielding layer, it is configured to shield electromagnetic radiation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to a radio frequency microsystem based on a microwave absorbing shielding structure. Background Technology

[0002] As radio frequency system-in-package (RF SiP) technology advances towards high power, multi-chip heterogeneous integration, and RF miniaturization, the variety of radiation sources within the limited space of RF SiP is increasing. These sources exhibit different radiation frequencies and characteristics, leading to a more complex electromagnetic environment within the RF SiP. Therefore, RF SiP design requires the rational design and utilization of novel absorbing materials to improve the electromagnetic environment and ensure system stability.

[0003] Currently, the main methods for improving the electromagnetic environment of RF SiP (Radio Frequency Identification Platform) are shielding and absorption. Shielding often uses a grounded metal casing, which effectively shields electromagnetic radiation. However, it cannot absorb electromagnetic radiation; the radiation generated by the radiation source inside the RF SiP cavity is confined within the metal casing, causing electromagnetic pollution within the cavity and potentially leading to cavity resonance and self-excitation. Therefore, in addition to electromagnetic shielding, absorption is also necessary. Furthermore, the metal casing in shielding solutions is relatively thick, often on the order of millimeters, increasing the thickness of the RF SiP. Currently, absorption materials often use composite magnetic materials or porous dielectric materials, which can absorb electromagnetic waves in specific frequency bands. These materials are mostly on the order of millimeters or centimeters, but the usable space in RF SiP is mostly on the order of micrometers (µm), making the material thickness a problem when applying absorption materials. Therefore, considering these two points, it is difficult to apply existing absorption materials to RF SiPs to achieve high absorption rates of electromagnetic radiation. Summary of the Invention

[0004] The objective of this invention is to provide a radio frequency microsystem based on an absorbing shielding structure. By combining an electromagnetic metamaterial layer, a resonant cavity, and a conformal shielding layer to form an absorbing shielding structure, the invention can simultaneously absorb and shield electromagnetic radiation generated within the radio frequency microsystem, thereby improving the electromagnetic environment within the radio frequency microsystem. Furthermore, the absorbing shielding structure is on the micrometer scale, meeting the size requirements of the radio frequency microsystem.

[0005] To address the problems existing in the prior art, this invention provides a radio frequency microsystem based on an absorbing shielding structure, comprising:

[0006] A radiation source, configured to produce electromagnetic radiation; and

[0007] An absorbing shielding structure configured to absorb and shield electromagnetic radiation generated by the radiation source, wherein the absorbing shielding structure comprises:

[0008] An electromagnetic metamaterial layer configured to absorb electromagnetic radiation;

[0009] A resonant cavity, configured to absorb electromagnetic radiation;

[0010] A conformal shielding layer, configured to shield electromagnetic radiation.

[0011] In one embodiment of the present invention, the conformal shielding layer is disposed on the top and sides of the radio frequency microsystem, and the electromagnetic metamaterial layer and the resonant cavity are located on the top of the radio frequency microsystem.

[0012] In one embodiment of the present invention, the resonant cavity includes:

[0013] Dielectric layer;

[0014] A resonant metal unit is arranged on the first side of the dielectric layer;

[0015] A partially conformal shielding layer is disposed on the second side of the dielectric layer; and

[0016] A metal pillar penetrates the dielectric layer and is connected to the resonant metal unit and the conformal shielding layer.

[0017] In one embodiment of the present invention, the electromagnetic metamaterial layer includes:

[0018] Dielectric layer;

[0019] Electromagnetic metamaterial units, which are arranged on the first side of the dielectric layer; and

[0020] A partially conformal shielding layer is arranged on the second side of the dielectric layer.

[0021] In one embodiment of the present invention, the resonant metal unit comprises a plurality of metal plates, and each metal plate is connected to a metal post.

[0022] In one embodiment of the present invention, multiple electromagnetic metamaterial units are arranged in the central blank area of ​​a resonant metal unit composed of multiple metal sheets.

[0023] In one embodiment of the present invention, the resonant metal unit and the electromagnetic metamaterial unit are formed by a metal rewiring process.

[0024] In one embodiment of the present invention, it further includes:

[0025] A molding layer that encapsulates the radiation source;

[0026] A metal interconnect structure electrically connected to the radiation source and electrically connected to the conformal shielding layer; and

[0027] Solder balls, which are electrically connected to the metal interconnect structure.

[0028] In one embodiment of the present invention, the electromagnetic metamaterial layer and the resonant cavity are located on the encapsulation layer.

[0029] In one embodiment of the present invention, the radiation source includes a chip.

[0030] The present invention has at least the following beneficial effects: The radio frequency microsystem based on an absorbing shielding structure disclosed in this invention combines an electromagnetic metamaterial layer, a resonant cavity, and a conformal shielding layer to form an absorbing shielding structure. The electromagnetic metamaterial layer and the resonant cavity can absorb electromagnetic radiation, while the conformal shielding layer can shield electromagnetic radiation. This absorbing shielding structure can simultaneously absorb and shield electromagnetic radiation generated within the radio frequency microsystem, improving the electromagnetic environment within the radio frequency microsystem. The absorbing shielding structure is on the micrometer scale, meeting the size requirements of the radio frequency microsystem. The absorption frequency of the electromagnetic metamaterial layer can be changed by altering the size of the electromagnetic metamaterial unit. The natural frequency of the resonant cavity, i.e., the absorption frequency, can be changed by adjusting the thickness of the dielectric layer, the spacing of the resonant metal units, and the spacing of the metal pillars. Attached Figure Description

[0031] To further illustrate the above and other advantages and features of the various embodiments of the present invention, a more specific description of the various embodiments of the present invention will be presented with reference to the accompanying drawings. It is to be understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by identical or similar reference numerals for clarity.

[0032] Figure 1 A schematic diagram of a conformal shielding structure according to the prior art is shown;

[0033] Figure 2 A schematic diagram of a radio frequency microsystem based on an absorbing shielding structure according to an embodiment of the present invention is shown.

[0034] Figure 3 A partial schematic diagram of an electromagnetic metamaterial layer according to an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram of the arrangement of multiple electromagnetic metamaterial units according to an embodiment of the present invention is shown;

[0036] Figure 5 A partial schematic diagram of a resonant cavity according to an embodiment of the present invention is shown;

[0037] Figure 6 A schematic diagram of the arrangement of the resonant metal unit according to an embodiment of the present invention is shown;

[0038] Figure 7 A schematic diagram of the arrangement of electromagnetic metamaterial units and resonant metal units according to an embodiment of the present invention is shown; and

[0039] Figure 8 The absorption rate curves of the electromagnetic metamaterial layer and the resonant cavity according to an embodiment of the present invention are shown. Detailed Implementation

[0040] It should be noted that the components in the accompanying drawings may be shown exaggerated for illustrative purposes and may not be to scale.

[0041] In this invention, the various embodiments are merely intended to illustrate the solutions of the invention and should not be construed as limiting.

[0042] In this invention, unless otherwise specified, the quantifiers “a” and “one” do not exclude scenarios involving multiple elements.

[0043] It should also be noted that, in the embodiments of the present invention, only a portion of the parts or components may be shown for clarity and simplicity. However, those skilled in the art will understand that, under the teachings of the present invention, the required parts or components can be added as needed for specific scenarios.

[0044] It should also be noted that within the scope of this invention, the terms "same", "equal", and "equal to" do not mean that the two values ​​are absolutely equal, but allow for a certain reasonable error. In other words, the terms also cover "substantially the same", "substantially equal", and "substantially equal to".

[0045] It should also be noted that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not explicitly or implicitly suggest that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] Furthermore, the embodiments of the present invention describe the process steps in a specific order; however, this is only for the convenience of distinguishing each step, and is not intended to limit the order of the steps. In different embodiments of the present invention, the order of each step can be adjusted according to the process.

[0047] Figure 1 A schematic diagram of a conformal shielding structure according to the prior art is shown.

[0048] like Figure 1 As shown, the chip 101 inside the package structure emits electromagnetic radiation in all directions. Metal layers are arranged on the top and around the package structure to form a grounded conformal shielding layer 102. The conformal shielding layer can effectively shield electromagnetic radiation, but it cannot absorb electromagnetic radiation.

[0049] Figure 2 A schematic diagram of a radio frequency microsystem based on an absorbing shielding structure according to an embodiment of the present invention is shown.

[0050] like Figure 2 As shown, a radio frequency microsystem based on a microwave absorbing shielding structure includes a chip 201, a molding layer 202, a metal interconnect structure 203, solder balls 204, a conformal shielding layer 205, an electromagnetic metamaterial unit 206, a dielectric layer 207, a metal pillar 208, and a resonant metal unit 209.

[0051] Chip 201 is located in molding compound 202 and is electrically connected to metal interconnect structure 203. Chip 201 is an electromagnetic radiation source, thereby generating electromagnetic radiation in molding compound 202 and polluting the electromagnetic environment of the radio frequency microsystem. Molding compound 202 may be, for example, an epoxy molding compound.

[0052] Solder ball 204 is located at the bottom of the RF microsystem and is electrically connected to metal interconnect structure 104 for electrical connection to the outside world.

[0053] A conformal shielding layer 205 is disposed on the top and four sides of the RF microsystem, enclosing the RF microsystem and electrically connected to the metal interconnect structure 203. The conformal shielding layer 205 can shield electromagnetic radiation generated by an electromagnetic radiation source. The conformal shielding layer 205 is formed by sputtering metal on the top and sides of the RF microsystem. The conformal shielding layer prepared by this method has two advantages: first, the metal layer is thin; second, the metal layer is conformal to the surface of the RF microsystem, with no air gaps, which can further reduce the thickness.

[0054] The electromagnetic metamaterial unit 206, the dielectric layer 207, and the conformal shielding layer 205 located on top of the radio frequency microsystem can constitute the electromagnetic metamaterial layer 20. The electromagnetic metamaterial unit 206 is fabricated using a metal rewiring process.

[0055] The resonant metal unit 209, dielectric layer 207, metal pillar 208, and conformal shielding layer 205 located on top of the RF microsystem can form a resonant cavity 21 to absorb electromagnetic radiation. The resonant metal unit 209 is fabricated using a metal rewiring process. The dielectric layer 207 can be, for example, an epoxy molding compound.

[0056] The thickness of the conformal shielding layer 205, the electromagnetic metamaterial unit 206, and the resonant metal unit 209 is 3-30 micrometers.

[0057] The electromagnetic metamaterial layer 20 and the resonant cavity 21 form an absorbing structure located above the molding layer 202, which can absorb the electromagnetic radiation generated by the chip 201. By utilizing the integrated thin-layer absorbing shielding structure of the electromagnetic metamaterial layer, resonant cavity, and conformal shielding layer, the thickness of the absorbing and shielding structure of the RF microsystem is reduced, thereby improving the electromagnetic environment within the RF microsystem.

[0058] Figure 3 A partial schematic diagram of an electromagnetic metamaterial layer according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of the arrangement of multiple electromagnetic metamaterial units according to an embodiment of the present invention is shown.

[0059] like Figure 3 As shown, electromagnetic metamaterial unit 301 is arranged on the first side of dielectric layer 302, and partially conformal shielding layer 303 is arranged on the second side of dielectric layer 302. The thickness of dielectric layer 302 varies depending on the electromagnetic radiation frequency and the material properties of the dielectric layer, but the thickness is on the order of micrometers, which is smaller than the traditional millimeter and centimeter orders of magnitude.

[0060] The conformal shielding layer 303 can shield electromagnetic radiation to prevent electromagnetic radiation from escaping, and can also shield the influence of external electromagnetic radiation on the radio frequency microsystem. The electromagnetic metamaterial unit 301 can absorb electromagnetic radiation.

[0061] like Figure 4 As shown, multiple electromagnetic metamaterial units 301 are periodically arranged on the dielectric layer 302 to form an electromagnetic metamaterial layer.

[0062] Figure 5 A partial schematic diagram of a resonant cavity according to an embodiment of the present invention is shown; Figure 6 A schematic diagram of the arrangement of resonant metal units according to an embodiment of the present invention is shown.

[0063] like Figure 5 As shown, a resonant metal unit 401 is arranged on the first side of the dielectric layer 402, a conformal shielding layer 403 is arranged on the second side of the dielectric layer 402, and a metal pillar 404 penetrates the dielectric layer 402 and is connected to the resonant metal unit 401 and the conformal shielding layer 403. The resonant metal unit 401 includes multiple metal sheets, each of which is connected to a metal pillar 404.

[0064] like Figure 6 As shown, multiple resonant metal units 401 are periodically arranged on the dielectric layer 402 to form a resonant metal layer. The resonant metal layer, together with the corresponding metal pillars, dielectric layer, and conformal shielding layer, constitute a resonant cavity.

[0065] Figure 7 A schematic diagram of the arrangement of electromagnetic metamaterial units and resonant metal units according to an embodiment of the present invention is shown.

[0066] like Figure 7 As shown, multiple periodically arranged electromagnetic metamaterial units 502 are arranged in the blank area in the middle of the resonant metal unit 501 composed of multiple metal sheets. The resonant metal unit 501 and the electromagnetic metamaterial unit 502 are periodically arranged on the dielectric layer 503.

[0067] The absorption principle of a resonant cavity is as follows:

[0068] The absorption principle of a resonant cavity is to capture electromagnetic wave energy in free space by utilizing the inherent resonance characteristics. This energy is dissipated through the dielectric loss of the dielectric layer and the ohmic loss of the metal surface (resonant metal units, metal pillars, conformal shielding layer), thus achieving the absorption effect. By adjusting parameters such as the thickness of the dielectric layer, the spacing of the resonant metal units, and the spacing of the metal pillars, the natural frequency of the resonant cavity, i.e., the absorption frequency, can be changed.

[0069] Figure 8 The absorption rate curves of the electromagnetic metamaterial layer and the resonant cavity according to an embodiment of the present invention are shown.

[0070] like Figure 8 As shown, the resonant frequency corresponding to the electromagnetic metamaterial layer is f1, and the absorption frequency corresponding to the resonant cavity is f2. When only the electromagnetic metamaterial layer is present, the absorption bandwidth of the absorbing structure is only w1. However, when the resonant cavity is introduced, the absorption bandwidth increases by w2, and the right side of the absorption rate curve becomes the dashed line, meaning the total absorption bandwidth is w1 + w2. The introduction of the resonant cavity greatly increases the absorption bandwidth. By adjusting the resonant frequencies of the electromagnetic metamaterial layer and the resonant cavity, the absorption rate and absorption bandwidth can be changed. The resonant frequency of the electromagnetic metamaterial layer can be changed by altering the size of the electromagnetic metamaterial unit.

[0071] The present invention has at least the following beneficial effects: The radio frequency microsystem based on an absorbing shielding structure disclosed in this invention combines an electromagnetic metamaterial layer, a resonant cavity, and a conformal shielding layer to form an absorbing shielding structure. The electromagnetic metamaterial layer and the resonant cavity can absorb electromagnetic radiation, while the conformal shielding layer can shield electromagnetic radiation. This absorbing shielding structure can simultaneously absorb and shield electromagnetic radiation generated within the radio frequency microsystem, improving the electromagnetic environment within the radio frequency microsystem. The absorbing shielding structure is on the micrometer scale, meeting the size requirements of the radio frequency microsystem. The absorption frequency of the electromagnetic metamaterial layer can be changed by altering the size of the electromagnetic metamaterial unit. The natural frequency of the resonant cavity, i.e., the absorption frequency, can be changed by adjusting the thickness of the dielectric layer, the spacing of the resonant metal units, and the spacing of the metal pillars.

[0072] While some embodiments of the present invention have been described in this application, those skilled in the art will understand that these embodiments are merely illustrative. Numerous variations, alternatives, and improvements will arise in those skilled in the art under the teachings of this invention without departing from its scope. The appended claims are intended to define the scope of the invention and thereby cover methods and structures within the scope of the claims themselves and their equivalents.

Claims

1. A radio frequency microsystem based on an absorbing shielding structure, characterized in that, include: A radiation source configured to produce electromagnetic radiation; as well as An absorbing shielding structure configured to absorb and shield electromagnetic radiation generated by the radiation source, wherein the absorbing shielding structure comprises: An electromagnetic metamaterial layer configured to absorb electromagnetic radiation; A resonant cavity, configured to absorb electromagnetic radiation; A conformal shielding layer, configured to shield electromagnetic radiation; the conformal shielding layer is formed by sputtering metal on top of and around the RF microsystem. The electromagnetic metamaterial layer includes: a dielectric layer; electromagnetic metamaterial units disposed on a first side of the dielectric layer; and a partially conformal shielding layer disposed on a second side of the dielectric layer. The resonant cavity includes: a dielectric layer; resonant metal units arranged on a first side of the dielectric layer, each resonant metal unit comprising four metal plates distributed vertically and horizontally, and each metal plate connected to a metal pillar; a partially conformal shielding layer arranged on a second side of the dielectric layer; and metal pillars penetrating the dielectric layer and connected to the resonant metal units and the conformal shielding layer; the absorption frequency of the resonant cavity can be changed by adjusting the thickness of the dielectric layer, the spacing of the resonant metal units, and the spacing of the metal pillars. Multiple electromagnetic metamaterial units are arranged in the middle blank area of ​​the resonant metal unit composed of four metal sheets. The four metal sheets surround the electromagnetic metamaterial unit, and the resonant metal unit and the electromagnetic metamaterial unit are periodically arranged on the dielectric layer. The resonant metal unit and the electromagnetic metamaterial unit are formed by a metal rewiring process. The thickness of the conformal shielding layer, the electromagnetic metamaterial unit, and the resonant metal unit is 3 micrometers to 30 micrometers.

2. The radio frequency microsystem based on the absorbing shielding structure according to claim 1, characterized in that, The conformal shielding layer is arranged on the top and sides of the radio frequency microsystem, and the electromagnetic metamaterial layer and the resonant cavity are located on the top of the radio frequency microsystem.

3. The radio frequency microsystem based on the absorbing shielding structure according to claim 1, characterized in that, Also includes: A molding layer that encapsulates the radiation source; A metal interconnect structure electrically connected to the radiation source and electrically connected to the conformal shielding layer; as well as Solder balls, which are electrically connected to the metal interconnect structure.

4. The radio frequency microsystem based on the absorbing shielding structure according to claim 3, characterized in that, The electromagnetic metamaterial layer and the resonant cavity are located on top of the encapsulation layer.

5. The radio frequency microsystem based on the absorbing shielding structure according to claim 1, characterized in that, The radiation source includes a chip.

Images