CN115117630A

CN115117630A - Antenna structure and forming method thereof

Info

Publication number: CN115117630A
Application number: CN202111314038.2A
Authority: CN
Inventors: 林政贤; 谢筱琪
Original assignee: Nanya Circuit Board Co ltd
Current assignee: Nanya Circuit Board Co ltd
Priority date: 2021-03-17
Filing date: 2021-11-08
Publication date: 2022-09-27
Also published as: TWI811648B; TW202239058A

Abstract

An antenna structure includes a core substrate and a pair of patch antennas. The pair of patch antennas are oppositely arranged on opposite side walls of the core substrate, and the core substrate between the pair of patch antennas is a cavity which does not contain a conductive material. The present disclosure also relates to a method of forming an antenna structure.

Description

Antenna structure and forming method thereof

Technical Field

Embodiments of the present invention relate to antenna structures, and more particularly, to a sidewall type antenna structure and a method for forming the same.

Background

Electronic devices often include integrated chips (integrated chips) with wireless communication elements. In general, an integrated chip may use wireless communication elements that include an off-chip antenna (i.e., an external antenna that is not integrated into the integrated chip) or an on-chip antenna (i.e., an antenna that is integrated into the integrated chip). The antenna for the high-frequency wireless communication element may use a patch antenna (patch antenna) provided on a high-frequency substrate or a high-frequency printed circuit board.

In recent years, the demand for wireless communication in consumer electronic products (e.g., smart phones, smart wearable devices, tablet computers, or satellite navigation systems for vehicles, etc.) has been increasing, and the electronic products are expected to have lighter weight, thinner size, and better performance. In some electronic devices using wireless communication elements including off-chip antennas, it may not be possible to reduce the product size because the off-chip antenna occupies additional volume. For these devices, wireless communication elements including on-chip antennas may be used to reduce product size. While existing on-chip antennas have been generally desirable, they have not been satisfactory in all respects.

Disclosure of Invention

An embodiment of the present invention provides an antenna structure, including: a core substrate and a pair of patch antennas. The pair of patch antennas are oppositely arranged on opposite side walls of the core substrate, and the core substrate between the pair of patch antennas is a cavity which does not contain a conductive material.

The embodiment of the invention provides a method for forming an antenna structure, which comprises the following steps: a core substrate is provided, which has a first antenna layer on the top surface and a second antenna layer under the bottom surface. The first antenna layer and the core substrate are patterned to form a first opening and a second opening exposing the second antenna layer, wherein the first opening and the second opening are positioned on two opposite sides of the core substrate. Filling the third antenna layer into the first opening and the second opening. The first antenna layer and the second antenna layer are patterned to expose the core substrate and leave the first antenna layer and the third antenna layer surrounding the third antenna layer and a portion of the second antenna layer under the core substrate. A dicing process is performed on the core substrate, the first antenna layer, the second antenna layer, and the third antenna layer along a loop path. After the cutting process, a pair of patch antennas embedded in opposite side walls of the core substrate in the annular path are formed on the first antenna layer, the second antenna layer and the third antenna layer in the annular path, the pair of patch antennas are oppositely arranged, and the core substrate between the pair of patch antennas is a cavity which does not contain a conductive material.

An embodiment of the present invention further provides a method for forming an antenna structure, including: a core substrate is provided, wherein a first antenna layer is arranged above the top surface of the core substrate, and a second antenna layer is arranged below the bottom surface of the core substrate. A first opening and a second opening are formed through the first antenna layer, the core substrate and the second antenna layer, wherein the first opening and the second opening are located on two opposite sides of the core substrate. And forming a third antenna layer on the side walls of the first opening and the second opening, on the top surface of the first antenna layer and under the bottom surface of the second antenna layer. The first antenna layer, the second antenna layer, and the third antenna layer are patterned to expose the core substrate and leave the first antenna layer, the second antenna layer, and the third antenna layer adjacent to the first opening and the second opening, and leave the third antenna layer on sidewalls of the first opening and the second opening. And performing a cutting process on the core substrate, the first antenna layer, the second antenna layer and the third antenna layer along the loop path. After the cutting process, the first antenna layer, the second antenna layer and the third antenna layer in the annular path form a pair of patch antennas on the surfaces of a pair of gaps of opposite side walls of the core substrate in the annular path, the pair of gaps are oppositely arranged, and the core substrate between the pair of patch antennas is a cavity which does not contain a conductive material.

Drawings

The embodiments of the present invention will be described in detail below with reference to the attached drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale and are merely illustrative. In fact, the dimensions of the elements may be arbitrarily expanded or reduced to clearly illustrate the features of the embodiments of the present invention.

Fig. 1A and 2 are perspective views illustrating an antenna structure according to some embodiments of the present invention.

Fig. 1B is a top view of an antenna structure, according to some embodiments of the present invention.

Fig. 3A is a perspective view illustrating an antenna structure according to other embodiments of the present invention.

Fig. 3B is a top view of an antenna structure according to further embodiments of the present invention.

Fig. 4, 5, 6A-8A, and 10A are cross-sectional views illustrating a process of forming an antenna structure according to some embodiments of the present invention.

Fig. 6B-8B, 9A, 9B, and 10B are top views illustrating a process of forming an antenna structure according to some embodiments of the present invention.

Fig. 11-14 are cross-sectional views illustrating a process of forming an antenna structure according to some embodiments of the present invention.

Fig. 15, 16A-18A, and 20A-21A are cross-sectional views illustrating processes for forming an antenna structure according to other embodiments of the present invention.

Fig. 16B-18B, 19 and 20B are top views illustrating fabrication of antenna structures according to other embodiments of the present invention.

Fig. 21B is a perspective view illustrating an antenna structure according to further embodiments of the present invention.

Wherein the reference numerals are as follows:

10, 20: antenna structure

100: core substrate

110: solder mask layer

101: first antenna layer

102: second antenna layer

103: third antenna layer

104: fourth antenna layer

105: fifth antenna layer

106: sixth antenna layer

107: seventh antenna layer

111: a first dielectric layer

112: a second dielectric layer

116: connecting piece

A1, a2, A3, a4, a5, a 6: patch antenna pair

C, C1, C2, C6: hollow cavity

D: distance between two adjacent devices

D1, D2, D3: direction of rotation

N: gap(s)

OP, OP1, OP2, OP3, OP4, OP5, OP 6: opening of the container

P: circular path

P _H1 ，P _H2 ，P _H3 ，P _V1 ，P _V2 ，P _V3 Cutting path

S: main surface

Detailed Description

The following disclosure provides many embodiments, or examples, for implementing different elements of the provided subject matter. Specific examples of components and arrangements thereof are described below to simplify the description of the embodiments of the invention. These are, of course, merely examples and are not intended to limit the invention from that described in the embodiments. For example, references in the description to a first element being formed on a second element may include embodiments in which the first and second elements are in direct contact, and may also include embodiments in which additional elements are formed between the first and second elements such that they are not in direct contact. Moreover, embodiments of the invention may have repeated reference numerals in various instances. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Furthermore, in some embodiments of the present invention, terms such as "connected," "interconnected," and the like, with respect to bonding, connecting, and the like, may refer to two structures being in direct contact, or may also refer to two structures not being in direct contact, unless otherwise specified, with another structure being interposed therebetween. And the terms coupled and connected should also be construed to include both structures being movable or both structures being fixed.

Also, spatially relative terms, such as "below" … …, "below," "lower," "above," "higher," and the like, may be used herein to facilitate describing one element or feature's relationship to another element or feature in the drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. When the device is turned to a different orientation (rotated 90 degrees or otherwise), the spatially relative adjectives used herein will also be interpreted in terms of the turned orientation.

As used herein, the term "about", "about" or "substantially" generally means within 20%, preferably within 10%, and more preferably within 5%, or within 3%, or within 2%, or within 1%, or within 0.5% of a given value. Where a given value is an approximate value, that is, where the meaning of "about", "about" or "substantial" is not expressly stated, that given value may still connote the meaning of "about", "about" or "substantial".

Some embodiments of the invention are described below in which additional steps may be provided before, during, and/or after various stages described in the embodiments. Some of the stages described may be replaced or eliminated in different embodiments. The antenna structure of the embodiment of the invention can be added with additional components. Some of the components described may be replaced or eliminated in different embodiments. Although some embodiments discussed are performed in a particular order of steps, these steps may be performed in another logical order.

In the prior art, a pair of patch antennas is usually disposed on the front surface of a substrate of an antenna structure, and in order to increase the thickness of a cavity between the pair of patch antennas to achieve high frequency performance, a plurality of layers may be formed between the pair of patch antennas. However, since the plurality of layers and the pair of patch antennas are formed in different steps, the thickness of the cavity between the pair of patch antennas may be affected by the materials and processes for forming the layers, so that the thickness of the cavity is not easily controlled, and the alignment of the pair of patch antennas formed in different steps is not easily controlled, thereby affecting the performance and yield of the patch antennas.

The embodiment of the invention provides an antenna structure and a forming method thereof, wherein a patch antenna pair is arranged on the side wall of a substrate of the antenna structure, so that the thickness of a cavity can be controlled. In addition, the method provided by the embodiment of the invention can simultaneously form the patch antenna pair so as to improve the accuracy of the alignment of the patch antennas.

Fig. 1A, 1B, and 2 are schematic diagrams illustrating an antenna structure 10 according to some embodiments of the present invention. Fig. 1A is a perspective view of the antenna structure 10, and fig. 1B is a top view of the antenna structure 10. The antenna structure 10 includes a core substrate 100, a first dielectric layer 111, a second dielectric layer 112, and a pair of patch antennas a1, a2, and A3. In some embodiments, the core substrate 100 material may include: Bismaleimide-Triazine resin (Bismaleimide Triazine resin), paper phenolic resin (paper phenolic resin), composite epoxy resin (composite epoxy), polyimide resin (polyimide resin), fiberglass (glass fiber), other suitable insulating materials, or combinations of the foregoing.

A first dielectric layer 111 and a second dielectric layer 112 may be optionally disposed above and below the main surface S of the core substrate 100, wherein the first dielectric layer 111 may be disposed above the core substrate 100, and the second dielectric layer 112 may be disposed below the core substrate 100. For example, the materials of the first dielectric layer 111 and the second dielectric layer 112 may be the same or different, and each of them includes: epoxy resin, bismaleimide-triazine resin, polyimide, a build-up film (ABF), polyphenylene oxide (PPO), polypropylene (PP), polymethyl methacrylate (PMMA), Polytetrafluoroethylene (PTFE), fiberglass, or other suitable materials. In some embodiments, the first dielectric layer 111 and the second dielectric layer 112 are pre-preg materials obtained by pre-impregnating insulating sheets, glass fibers, or other materials. According to some embodiments of the present invention, the core substrate 100, the first dielectric layer 111 and the second dielectric layer 112 may comprise the same material.

Referring to fig. 1B, it should be noted that, for clarity of illustrating the positions of the patch antenna and the core substrate, fig. 1B only shows a top view including the core substrate 100 and the patch antenna pairs a1, a2 and A3. Referring to fig. 1A and 1B, the patch antenna pairs a1, a2, and A3 are disposed on opposite sidewalls of the core substrate 100. The core substrate 100 between the pair of patch antennas is a cavity that does not contain a conductive material, such as cavity C1 between pair of patch antennas a1 and cavity C2 between pair of patch antennas a 2. Herein, "cavity" means not containing a conductive material, and does not mean that a void is necessarily formed therein (i.e., a void may or may not be included in the cavity), and thus, according to some embodiments of the present invention, a core substrate without a conductive material between pairs of patch antennas is referred to as a "cavity". In further embodiments, the core substrate and the dielectric layer between the patch antenna pairs may also include a conductive material, and thus in such embodiments, the core substrate and the dielectric layer between the patch antenna pairs are also cavities. As shown in fig. 1B, the pair of patch antennas a1, a2, and A3 are embedded in opposite sidewalls of the core substrate 100, and one of the sidewalls of the patch antennas is coplanar with one of the sidewalls of the core substrate 100. The materials of the patch antenna pairs a1, a2, and A3 may include conductive materials, such as: copper, aluminum, tungsten, silver, gold, nickel, or combinations of the foregoing. As described below in the process of forming the antenna structure, the embodiments of the present invention can simultaneously form the pair of patch antennas to improve the alignment accuracy of the pair of patch antennas, and can determine the thickness of the cavity between the pair of patch antennas according to the product design to achieve the desired frequency performance.

In some embodiments, at least one of the patch antennas of the pair of patch antennas may extend above the top surface of the core substrate 100. For example, as shown in fig. 1A, one of the pair of patch antennas a1 extends higher than the top surface of the core substrate 100 in a direction D3 perpendicular to the main surface S of the core substrate 100. In some embodiments, at least one of the patch antennas in the pair of patch antennas may extend below the bottom surface of the core substrate 100. For example, as shown in fig. 1A, one of the pair of patch antennas a2 extends lower than the bottom surface of the core substrate 100 in a direction D3 perpendicular to the main surface S of the core substrate 100. According to some embodiments of the invention, the pair of patch antennas a1, a2 and A3 may also be embedded in the sidewalls of the first dielectric layer 111 and the second dielectric layer 112, and the pair of patch antennas may also extend to be higher than the first dielectric layer 111 or lower than the second dielectric layer 112 along the direction D3, and the patch antennas extending beyond the core substrate 100 may be referred to as antenna buildup.

The pair of patch antennas may have various shapes in a top view, as shown in fig. 1B, and may have a rectangular shape, a partially elliptical shape, a polygonal shape with a curvature at a portion of a corner, or other shapes. In embodiments including the first dielectric layer 111 or the second dielectric layer 112, the first dielectric layer 111 and the antenna build-up layer embedded therein may be referred to as a build-up structure, and similarly, the second dielectric layer 112 and the antenna build-up layer embedded therein may also be referred to as a build-up structure. The build-up structure may be disposed above or below the core substrate 100. The size of the patch antenna can be adjusted by using the layer-adding structure according to the application and design requirements of the product, and the number of the patch antennas can be one or more. For example, by forming a multi-layer structure including a core substrate by a build-up structure, the size of the patch antenna pair can be increased to achieve a predetermined frequency performance.

Referring to fig. 1A, in some embodiments, the antenna structure 10 may include a solder mask layer 110 covering the antenna patch pairs a1, A3 and the top surface of the first dielectric layer 111. The antenna structure 10 may also include a solder mask layer 110 covering the antenna patch pairs a1, a2, A3 and the bottom surface of the second dielectric layer 112. In some embodiments, the solder mask layer 110 can be a photosensitive material (e.g., a uv-based photosensitive material), a thermo-sensitive material (e.g., a thermosetting thermo-sensitive material), other suitable materials, or a combination thereof. For example, the solder mask layer 110 may include: epoxy, urethane, ethyl ester, or other materials.

Referring to fig. 2, the antenna structure 10 may further include a plurality of connecting members 116 disposed on the solder mask layer 110. The connector 116 may be used to transmit signals. The material of the connection member 116 may include a metal material, such as tin or nickel. As shown in fig. 2, depending on the product characteristic requirements, in the embodiment including the first dielectric layer 111 and the second dielectric layer 112, the patch antenna may extend only above the first dielectric layer 111 and not below the second dielectric layer 112, such as the pair a5 of patch antennas shown in fig. 2; or the patch antenna may extend only above the top surface of the core substrate 100 and below the bottom surface of the core substrate 100 without extending above the first dielectric layer 111 and below the second dielectric layer 112, as shown in the patch antenna pair a4 of fig. 2.

Fig. 3A and 3B are schematic diagrams illustrating an antenna structure 20 according to other embodiments of the present invention, wherein similar components to those of the antenna structure 10 are denoted by the same reference numerals, and the related description is not repeated herein. Fig. 3A illustrates a perspective view of the antenna structure 20, and fig. 3B illustrates a top view of the antenna structure 20. It should be noted that fig. 3B only shows the core substrate 100 and patch antenna pair a6 for clarity of the placement of the patch antennas and the core substrate. Referring to fig. 3A and 3B, the core substrate 100 of the antenna structure 20 has a pair of notches N disposed opposite to each other on opposite sidewalls. The pair of notches N penetrate the core substrate 100, and the pair of patch antennas a6 are respectively disposed on the sidewalls of the core substrate 100 exposed by the notches N. As shown in fig. 3A and 3B, the pair of patch antennas a6 of the antenna structure 20 is compliantly disposed along the notch N, so that the pair of patch antennas a6 is recessed in the sidewall of the core substrate 100. In some embodiments, the patch-antenna pair a6 may extend above the top surface of the core substrate 100 in a direction D3 perpendicular to the major surface S of the core substrate 100 and/or the patch-antenna pair a6 may extend below the bottom surface of the core substrate 100 in a direction D3 perpendicular to the major surface S of the core substrate 100. In some embodiments, the core substrate 100 between the pair of patch antennas is a cavity that does not contain conductive material, such as cavity C6 between pair of patch antennas a 6.

According to some embodiments of the present invention, the antenna structure 20 may include a first dielectric layer 111 disposed on the core substrate 100 and/or a second dielectric layer 112 disposed under the core substrate 100. In these embodiments, the pair of notches N also penetrate the first dielectric layer 111 and/or the second dielectric layer 112, and the patch antenna pair a6 is disposed on the sidewalls of the first dielectric layer 111 and/or the second dielectric layer 112 exposed by the notches N, respectively, and recessed into the sidewalls of the first dielectric layer 111 and/or the second dielectric layer 112. The patch antenna pair a6 may extend above the first dielectric layer 111 and/or below the second dielectric layer 112 along direction D3. It should be noted that the pair of patch antennas a6 over the pair of gaps N shown in fig. 3A is merely exemplary, and a plurality of pairs of patch antennas may be disposed in a plurality of pairs of gaps on the sidewalls of the core substrate 100, the first dielectric layer 111, and/or the second dielectric layer 112 of the antenna structure 20, respectively, and a plurality of pairs of gaps may be further disposed on another pair of opposite sidewalls of the core substrate 100, or another pair of opposite sidewalls of the core substrate 100, the first dielectric layer 111, and the second dielectric layer 112.

Fig. 4, 5, 6A-8A, 6B-8B, 10A, 10B, and 11-14 are schematic diagrams illustrating a process for forming the antenna structure 10 according to some embodiments of the present invention. Referring to fig. 4, a core substrate 100 is provided. The core substrate 100 has a first antenna layer 101 above the top surface and a second antenna layer 102 below the bottom surface. Then, as shown in fig. 5, 6A and 6B, the first antenna layer 101 and the core substrate 100 are patterned to form an opening OP1 and an opening OP2 exposing the second antenna layer 102 on two opposite sides of the core substrate 100. Fig. 5 and 6A are cross-sectional views illustrating the patterned antenna structure 10, and fig. 6B is a top view illustrating the antenna structure 10, wherein the cross-section a-a in fig. 6B may correspond to fig. 6A. As shown in fig. 5, the process of patterning the first antenna layer 101 and the core substrate 100 may include patterning the first antenna layer 101 to form an opening OP exposing the core substrate 100, and then patterning the core substrate 100 to form an opening OP1 and an opening OP2 exposing the second antenna layer 102, as shown in fig. 6A and 6B. In some embodiments, the process of patterning the first antenna layer 101 may include forming a patterned mask (not shown) on the first antenna layer 101, removing a portion of the first antenna layer 101 using an etching process to form the opening OP, and removing the patterned mask. The first antenna layer 101 and the second antenna layer 102 may comprise the same or different materials, for example, may comprise: copper, aluminum, tungsten, silver, gold, or combinations of the foregoing. The patterning mask may include: dry film, liquid photoresist, other suitable materials, or combinations thereof. In embodiments where the material of the first antenna layer 101 comprises copper, the etching process may comprise a wet etching process, wherein the etchant used comprises: sulfuric acid-hydrogen peroxide solution, sodium chlorate solution, or other suitable solution. The patterned mask may be removed using an appropriate etchant, such as: copper chloride solution, sulfuric acid-hydrogen peroxide solution, sodium hydroxide solution, potassium hydroxide solution, amine-based solution, or other suitable solution. In some embodiments, the process of patterning the core substrate 100 includes removing the core substrate 100 under the opening OP using a laser.

Referring next to fig. 7A, 7B, 8A, and 8B, fig. 7A and 8A are cross-sectional views of the antenna structure 10, and fig. 7B and 8B are top views of the antenna structure 10, wherein the a-a cross-section may correspond to fig. 7A and 8A, respectively. In fig. 7A and 7B, the third antenna layer 103 is filled into the opening OP1 and the opening OP 2. The material of the third antenna layer 103 may be the same as the material of the first antenna layer 101 and/or the second antenna layer 102. In some embodiments, the third antenna layer 103 may be formed by a deposition process or an electroplating process to fill the opening OP1 and the opening OP 2. Next, as shown in fig. 8A and 8B, the first antenna layer 101 and the second antenna layer 101 are patterned. The patterning process shown in fig. 8A and 8B may be the same as or similar to the process of patterning the first antenna layer 101 to form the opening OP. In some embodiments, the core substrate 100 is exposed after patterning, and the first antenna layer 101 is left surrounding the third antenna layer 103, and the third antenna layer 103 and a portion of the second antenna layer 102 under the core substrate 100 are left.

Referring to fig. 9A, a cutting process is performed along the circular path P. In some embodiments, the dicing process includes dicing the core substrate 100, the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103. According to some embodiments of the invention, the loop path P may also be constituted by a plurality of cutting paths. FIG. 9B also illustrates a plurality of antenna structures that may be formed using processes similar to those described above, including forming a plurality of openings simultaneously and then forming an antenna layer in the openings simultaneously, and performing a process including cutting a path P _V1 、P _V2 And P _V3 And a cutting path P _H1 、P _H2 、P _H3 The antenna structure 10 shown in fig. 1A is formed by the dicing process. As shown in FIG. 9B, the circular path P may include two cutting paths P _H1 、P _H2 And two cutting paths P therewith _H1 、P _H2 Two other cutting paths P perpendicular _V1 、P _V2 . In other embodiments, the circular path P may be circular, elliptical, rectangular, diamond-shaped, or other suitable shapes, depending on design and/or process requirements.

Fig. 10A and 10B illustrate the antenna structure 10 after a dicing process, where fig. 10A is a cross-sectional view, and fig. 10B is a top view, where the cross-section a-a may correspond to fig. 10A. The first antenna layer 101, the second antenna layer 102 and the third antenna layer 103 in the loop path P form a pair of patch antennas embedded in opposite sidewalls of the core substrate 100 in the loop path P, the pair of patch antennas are disposed opposite to each other and the core substrate 100 between the pair of patch antennas is a cavity C containing no conductive material. In some embodiments, the pair of patch antennas formed by the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 may correspond to the pair of patch antennas a4 of fig. 2. As described above, the pair of patch antennas of the present disclosure can be formed in the openings formed in the same process (for example, the openings OP1 and OP2, refer to fig. 6B), so that the alignment accuracy between the pair of patch antennas can be improved, for example, about 30% better than that of the conventional pair of patch antennas formed on the substrate at a non-same time. In addition, since the cavity distance (or the cavity thickness) between the pair of conventional patch antennas is determined by the multi-layer material between the pair of patch antennas, the process of forming the multi-layer material may affect the uniformity of the multi-layer material, resulting in the cavity distance being not easily controlled and the cavity distance being limited by the number of layers of the multi-layer material. In some embodiments of the present invention, the cavity distance between the patch antennas (e.g., the cavity C, see fig. 10B) may be the distance D between the oppositely disposed antenna layers (e.g., the first antenna layer 101, see fig. 10B) after the patterning and cutting processes, so that the variation of the cavity distance (or thickness) can be better controlled through the patterning process, and the cavity distance is determined by the unit size of the antenna structure after the cutting process, thereby achieving the desired frequency performance. In addition, the embodiment of the invention does not need to add an additional material layer to increase the cavity distance, so that the manufacturing cost can be reduced.

Fig. 11-14 are cross-sectional views of build-up structures for forming antenna structures according to some embodiments of the invention. In some embodiments, after patterning the first antenna layer 101 and the second antenna layer 102 and before performing the dicing process, build-up structures may be formed on and/or under the core substrate. In some embodiments of the present invention, the first build-up structure and the second build-up structure may be formed simultaneously, i.e., build-up layers above and below the antenna structure 10 simultaneously. Referring to fig. 11, a first dielectric layer 111 is formed on the top surfaces of the first antenna layer 101, the third antenna layer 103 and the core substrate 100, a fourth antenna layer 104 is formed on the first dielectric layer 111, a second dielectric layer 112 is formed under the bottom surfaces of the second antenna layer 102 and the core substrate 100, and a sixth antenna layer 106 is formed under the second dielectric layer 112. In some embodiments, forming the first dielectric layer 111, the fourth antenna layer 104, the second dielectric layer 112, and the sixth antenna layer 106 includes laminating the material layer of the first dielectric layer 111 and the material layer of the fourth antenna layer 104 onto the top surfaces of the first antenna layer 101, the third antenna layer 103, and the core substrate 100 and laminating the material layer of the second dielectric layer 112 and the material layer of the sixth antenna layer 106 under the bottom surfaces of the second antenna layer 102 and the core substrate 100. In some embodiments, a portion of the first antenna build-up (e.g., the fifth antenna layer 105) may pass through the first dielectric layer 111 and connect to the third antenna layer 103. Similarly, in some embodiments, a portion of the second antenna build-up (e.g., the seventh antenna layer 107) may pass through the second dielectric layer 112 and connect to the second antenna layer 102.

Then, referring to fig. 12, a patterning process is performed to pattern the fourth antenna layer 104, the first dielectric layer 111, the sixth antenna layer 106, and the second dielectric layer 112 to form an opening OP3 and an opening OP 4. According to some embodiments of the present invention, the opening OP3 exposes the third antenna layer 103 and the opening OP4 exposes the second antenna layer 102 under the third antenna layer 103. The process of patterning the fourth antenna layer 104, the first dielectric layer 111, the sixth antenna layer 106, and the second dielectric layer 112 may be similar to the process described above with respect to fig. 5, 6A, and 6B.

The fifth antenna layer 105 is then filled into the opening OP3 and the seventh antenna layer 107 is filled into the opening OP4, as shown in fig. 13. The process of filling the fifth antenna layer 105 and the seventh antenna layer 107 may be similar to the process of filling the third antenna layer 103 into the opening OP1 and the opening OP2 described above with reference to fig. 7A and 7B. The fourth antenna layer 104 and the sixth antenna layer 106 are then patterned to expose the first dielectric layer 111 and the second dielectric layer 112, and leave the fourth antenna layer 104 surrounding the fifth antenna layer 105 and the sixth antenna layer 106 surrounding the seventh antenna layer 107, as shown in fig. 14. Thereby forming a first build-up structure comprising the first dielectric layer 111, the fourth antenna layer 104 and the fifth antenna layer 105 and a second build-up structure comprising the second dielectric layer 112, the sixth antenna layer 106 and the seventh antenna layer 107, wherein the fourth antenna layer 104 and the fifth antenna layer 105 may be collectively referred to as a first antenna build-up and the sixth antenna layer 106 and the seventh antenna layer 107 may be collectively referred to as a second antenna build-up. In some embodiments, after forming the build-up structure, a dicing process as shown in fig. 9A may be performed to dice the core substrate 100, the first antenna layer 101, the second antenna layer 102, the third antenna layer 103, the first build-up structure, and the second build-up structure, and after the dicing process, the first antenna layer 101, the second antenna layer 102, the third antenna layer 103, the first antenna build-up layer, and the second antenna build-up layer in the loop path P may form the patch antenna a1 or A3 as shown in fig. 1A-1B. In some embodiments, the first antenna layer 101, the second antenna layer 102, the third antenna layer 103, the first antenna build-up layer, and the second antenna build-up layer comprise the same material. In some embodiments, the core substrate 101, the first dielectric layer 111, and the second dielectric layer 112 comprise the same material.

In some embodiments, no antenna build-up may be formed during build-up. For example, only the first dielectric layer 111 is formed when the first build-up structure is formed, and the second dielectric layer 112 and the second antenna build-up layer are formed when the second build-up structure is formed. In these embodiments, after forming the build-up structure, a dicing process as shown in fig. 9A may be performed, and after dicing, the antenna layer and the second antenna build-up layer in the loop path P form the patch antenna a2 as shown in fig. 1A. Similarly, when the first build-up structure is formed, the first dielectric layer 111 and the first antenna build-up layer are formed, and when the second build-up structure is formed, only the second dielectric layer 112 is formed, after the cutting process, the patch antenna a5 shown in fig. 2 can be formed. In other embodiments, only the first build-up structure or only the second build-up structure may be formed. In alternative embodiments, the first build-up structure may be formed first and then the second build-up structure, or vice versa.

Although only one first build-up structure above the core substrate 100 or one second build-up structure below the core substrate 100 is shown in the above embodiments, the embodiments of the present invention may include a plurality of first build-up structures or second build-up structures, and may also include only one or more first build-up structures, or only one or more second build-up structures. According to some embodiments of the present invention, the area of the patch antenna on the sidewall of the core substrate and/or the dielectric layer may be adjusted by using the build-up structure to achieve the desired frequency performance according to the design or requirement of the product. Furthermore, not both patch antennas of a patch antenna pair need include an antenna buildup, for example, in patch antenna pair a1 of fig. 1B, only one patch antenna may include an antenna buildup.

Fig. 15, 16A-18A, 16B-18B, 19, 20A-21A, and 20B-21B are diagrams illustrating processes for forming the antenna structure 20 according to further embodiments of the present invention. Referring first to fig. 15, a core substrate 100 is provided. The core substrate 100 has a first antenna layer 101 above the top surface and a second antenna layer 102 below the bottom surface. Next, as shown in fig. 16A and 16B (fig. 16A is a cross-sectional view of the antenna structure 20, fig. 16B is a top view of the antenna structure 20, and the cross-section a-a of fig. 16B may correspond to fig. 16A), openings OP5 and OP6 are formed on two opposite sides of the core substrate 100 through the first antenna layer 101, the core substrate 100, and the second antenna layer 102. In some embodiments, the process of forming the opening OP5 and the opening OP6 includes a forming-cutting process (otherwise referred to as a slot-fishing process).

Referring next to fig. 17A, 17B, 18A, and 18B, fig. 17A and 18A are cross-sectional views of the antenna structure 20, and fig. 17B and 18B are top views of the antenna structure 20, wherein the a-a cross-section may correspond to fig. 17A and 18A, respectively. In fig. 17A and 17B, the third antenna layer 103 is formed on the sidewalls of the opening OP5 and the second opening OP6, on the top surface of the first antenna layer 101, and under the bottom surface of the second antenna layer 102. In some embodiments, the process of forming the third antenna layer 103 may include using an electroplating process. Next, referring to fig. 18A and 18B, the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 are patterned to expose the core substrate 100, and leave the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 adjacent to the first opening OP5 and the second opening OP6, and leave the third antenna layer 103 on sidewalls of the first opening OP5 and the second opening OP 6. In some embodiments, the process of patterning the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 may include forming a patterned mask on the first antenna layer 103, removing a portion of the first antenna layer 103 by an etching process to expose a portion of the first antenna layer 101 and the second antenna layer 102, and removing the exposed portion of the first antenna layer 101 and the second antenna layer 102 by another etching process. In an embodiment in which the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 comprise the same material, the patterning process can be performed in the same etching process. The etching process may comprise a wet etching process, wherein the etchant used comprises: sulfuric acid-hydrogen peroxide solution, sodium chlorate solution, or other suitable solution.

Referring to fig. 19, a cutting process is performed on the core substrate 100, the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 along the loop path P. Fig. 20A and 20B illustrate the antenna structure 20 after a dicing process, where fig. 20A is a cross-sectional view and fig. 20B is a top view, where the cross-section a-a may correspond to fig. 20A. After the dicing, the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 in the loop path P form a pair of patch antennas on the surfaces of a pair of notches N of the opposite sidewalls of the core substrate 100 in the loop path P. In some embodiments, the patch antenna pair is compliantly disposed on the surface of the notch N. The notch N may be rectangular, semicircular, partially elliptical, polygonal with a portion of the corners having a curvature, or other shapes. As shown in fig. 20B, the pair of notches N are disposed oppositely, and the core substrate 100 between the pair of patch antennas is a cavity C containing no conductive material. The embodiment of the invention also comprises a plurality of antenna structures which can be formed by using the processes similar to the above, and a cutting process is carried out to form the patch antenna which is concave inwards to the core substrate of the antenna structures. In some embodiments, similar to fig. 9B, the loop path P of fig. 19 may also be made up of multiple cutting paths.

In some embodiments, before performing the cutting process, a solder mask layer 110 may be formed to cover the top and bottom surfaces of the core substrate 100, the third antenna layer 103, and the exposed sidewalls of the first antenna layer 101 and the second antenna layer 102, as shown in fig. 21A. For example, coating or dry film (dryfilm) lamination may be performed to form the solder mask layer 110. After the solder mask 110 is formed, a dicing process may be performed to form the antenna structure 20 as shown in fig. 21B. In some embodiments, the first antenna layer 101, the second antenna layer 102, and the third antenna layer 103 of the antenna structure 20 comprise the same material. In some embodiments, the first antenna layer 101 and the second antenna layer 102 of the antenna structure 20 shown in fig. 15 may be patterned to expose the substrate 100, then, a process similar to the above-mentioned process for forming a build-up structure is performed on the antenna structure 20 to form a first build-up structure on the core substrate 100 of the antenna structure 20 and a second build-up structure under the bottom surface of the core substrate 100 of the antenna structure 20, then, a patterning process (e.g., a forming and cutting process) is performed to form an opening penetrating through the first and second build-up structures (including the dielectric and the build-up antenna), the first antenna layer 101, the core substrate 100, and the second antenna layer 102, and then a third antenna layer 103 is formed on the sidewall of the opening, above the first build-up structure, and below the second build-up structure, and then the third antenna layer 103 is patterned and then a cutting process is performed, so as to form the patch antenna pair a6 shown in fig. 3A and 3B. In other embodiments, a patterning process (e.g., a forming and cutting process) may be performed on the antenna structure 10 shown in fig. 14 to form an opening penetrating through the fifth antenna layer 105, the third antenna layer 103, the second antenna layer 102, and the seventh antenna layer 107 and leave a portion of the fifth antenna layer 105, the third antenna layer 103, the second antenna layer 102, and the seventh antenna layer 107 on a sidewall of the opening, and then a cutting process is performed to form the pair of patch antennas a6 shown in fig. 3A and 3B. In other embodiments, the surface of the patch antenna may be treated, such as by electroplating, to form nickel, palladium, or gold on the surface of the patch antenna before performing the dicing process. In the embodiment of treating the surface of the patch antenna, a cutting process may be performed without forming a solder mask layer after the treatment.

In some embodiments, one antenna of an antenna pair may be configured as an antenna plane and the other antenna may be configured as a ground plane, respectively, with the cavity between the antenna pair acting as an insulator and a resonant cavity. Although the above embodiments are described as patch antennas, the embodiments of the present invention can also be applied to other antennas, such as micro-strip antennas.

The antenna structure and the forming method thereof provided by the embodiment of the invention comprise the steps of forming the patch antenna pairs on the side wall of the core substrate, improving the alignment accuracy between the patch antenna pairs, and controlling the cavity distance (or the cavity thickness) between the patch antenna pairs so as to achieve the required frequency efficiency. For example, the cavity distance between the patch antenna pair can be increased according to design requirements to improve performance. In addition, the forming method of the antenna structure provided by the embodiment of the invention can also reduce the cost of the manufacturing process.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. An antenna structure comprising:

a core substrate; and

the core substrate between the patch antennas is a cavity which does not contain conductive materials.

2. The antenna structure of claim 1, wherein the pair of patch antennas are embedded in opposing sidewalls of the core substrate, and a sidewall of each of the pair of patch antennas is coplanar with the sidewalls of the core substrate.

3. The antenna structure of claim 1, wherein a pair of notches are oppositely disposed on opposite sidewalls of the core substrate, the notches penetrate through the core substrate, and the patch antennas are respectively disposed on the sidewalls of the core substrate exposed by the notches.

4. The antenna structure of claim 1, wherein at least one of the pair of patch antennas extends above the top surface of the core substrate in a direction perpendicular to the major surface of the core substrate.

5. The antenna structure of claim 4, further comprising a solder mask covering the top surface of the core substrate and the top surface of the at least one patch antenna.

6. The antenna structure of claim 5, further comprising a plurality of connectors disposed on the solder mask.

7. The antenna structure of claim 1, wherein at least one of the pair of patch antennas extends below the bottom surface of the core substrate in a direction perpendicular to the major surface of the core substrate.

8. The antenna structure of claim 7, further comprising a solder mask covering the bottom surface of the core substrate and the bottom surface of the at least one patch antenna.

9. The antenna structure of claim 1 further comprising a build-up structure disposed above the top surface or below the bottom surface of the core substrate.

10. The antenna structure of claim 9 wherein the build-up structure comprises a dielectric layer and an antenna build-up layer.

11. A method of forming an antenna structure, comprising:

providing a core substrate, wherein a first antenna layer is arranged above the top surface of the core substrate, and a second antenna layer is arranged below the bottom surface of the core substrate;

patterning the first antenna layer and the core substrate to form a first opening and a second opening exposing the second antenna layer, wherein the first opening and the second opening are located at two opposite sides of the core substrate;

filling a third antenna layer into the first opening and the second opening;

patterning the first antenna layer and the second antenna layer to expose the core substrate and leave the first antenna layer and the third antenna layer surrounding the third antenna layer and a portion of the second antenna layer under the core substrate; and

performing a cutting process on the core substrate, the first antenna layer, the second antenna layer and the third antenna layer along a loop path, wherein

After the cutting process, a pair of patch antennas embedded in opposite sidewalls of the core substrate in the loop path are formed on the first antenna layer, the second antenna layer and the third antenna layer in the loop path, the pair of patch antennas are disposed opposite to each other, and the core substrate between the pair of patch antennas is a cavity not containing a conductive material.

12. The method of claim 11, further comprising forming a first build-up structure on the top surface of the core substrate after patterning the first and second antenna layers and before performing the dicing process, the first build-up structure comprising a first dielectric layer and a first antenna build-up layer, wherein a portion of the first antenna build-up layer extends through the first dielectric layer and connects to the third antenna layer.

13. The method of claim 12, wherein the dicing process further comprises dicing the first build-up structure along the loop path, wherein

After the cutting process, at least one patch antenna of the pair of patch antennas is formed on the first antenna layer, the second antenna layer, the third antenna layer and the first antenna build-up layer in the annular path.

14. The method of forming an antenna structure of claim 12, further comprising: forming a second build-up structure under the bottom surface of the core substrate, the second build-up structure including a second dielectric layer and a second antenna build-up layer, wherein a portion of the second antenna build-up layer passes through the second dielectric layer and is connected to the second antenna layer.

15. The method of claim 14, wherein the dicing process further comprises dicing the first build-up structure and the second build-up structure along the circular path, wherein the dicing process further comprises dicing the first build-up structure and the second build-up structure

After the cutting process, at least one patch antenna of the pair of patch antennas is formed on the first antenna layer, the second antenna layer, the third antenna layer, the first antenna build-up layer and the second antenna build-up layer in the loop path.

16. The method of claim 14, wherein the first antenna layer, the second antenna layer, the third antenna layer, the first antenna build-up layer, and the second antenna build-up layer comprise the same material, and the core substrate, the first dielectric layer, and the second dielectric layer comprise the same material.

17. A method of forming an antenna structure, comprising:

forming a first opening and a second opening through the first antenna layer, the core substrate and the second antenna layer, wherein the first opening and the second opening are located on two opposite sides of the core substrate;

forming a third antenna layer on the sidewalls of the first opening and the second opening, on the top surface of the first antenna layer, and under the bottom surface of the second antenna layer;

patterning the first antenna layer, the second antenna layer, and the third antenna layer to expose the core substrate and leave the first antenna layer, the second antenna layer, and the third antenna layer adjacent to the first opening and the second opening, and leave the third antenna layer on sidewalls of the first opening and the second opening; and

After the cutting process, a pair of patch antennas is formed on the surfaces of a pair of gaps of opposite side walls of the core substrate in the loop path on the first antenna layer, the second antenna layer and the third antenna layer in the loop path, the pair of gaps are oppositely arranged, and the core substrate between the pair of patch antennas is a cavity which does not contain conductive materials.

18. The method of forming an antenna structure of claim 17, further comprising: a build-up structure is formed over the top surface or under the bottom surface of the core substrate, wherein the build-up structure includes a dielectric layer and an antenna build-up layer.

19. The method of forming an antenna structure of claim 17, further comprising:

before the cutting process is performed, a solder mask is formed to cover the top and bottom surfaces of the core substrate and cover the third antenna layer.

20. The method of claim 17, wherein the first antenna layer, the second antenna layer, and the third antenna layer comprise the same material.