TWI849515B - Circuit board and method of fabricating the same - Google Patents

Abstract

A circuit board and a method of fabricating the same are provided in the present invention. The method includes filling a first silicone rubber material within a first shielding layer, and the first silicone rubber material wraps the first conductive via connecting to a first circuit layer; and filling a second silicone rubber material within a second shielding layer, and the second silicone rubber material wraps the second conductive via connecting to a second circuit layer. The first shielding layer and the second shielding layer include a low-frequency shielding layer and a high-frequency shielding layer, respectively. The silicone rubber material can be shielding material of electromagnetic radiation; thus, the circuit board of the present invention can shield the electromagnetic radiation in line of conducting signal effectively.

Description

Circuit board and manufacturing method thereof

The present invention relates to a circuit board and a manufacturing method thereof, and in particular to a circuit board with electromagnetic shielding effect and a manufacturing method thereof.

The signals generated by electronic devices include high-frequency signals and low-frequency signals, and both of them will generate electromagnetic waves. The electromagnetic waves generated by each electronic device may interfere with each other, which is called electromagnetic interference (EMI). Furthermore, with the miniaturization of electronic equipment products, the radiated electromagnetic field interference they generate is also more serious. Therefore, in order to reduce the problem of electromagnetic interference, the electromagnetic shielding effect of electronic components must be improved.

One aspect of the present invention is to provide a method for manufacturing a circuit board, which includes disposing a plurality of silicone rubber materials on a circuit layer to shield electromagnetic radiation generated by a signal.

Another aspect of the present invention is to provide a circuit board made by the method of the above aspect.

According to one aspect of the present invention, a method for manufacturing a circuit board is provided, which includes forming a groove in an insulating substrate; placing an electronic component in the groove, wherein the electronic component includes a first circuit layer; forming a first shielding layer on the insulating substrate and the electronic component, wherein the first shielding layer includes a first low-frequency shielding layer and a first high-frequency shielding layer; forming a plurality of first openings in the first shielding layer to expose the first circuit layer; filling a plurality of first silicone rubber materials in the plurality of first openings; forming a plurality of first conductive blind holes in the plurality of first silicone rubber materials, wherein the plurality of first The conductive blind via is electrically connected to the first circuit layer; a composite layer is formed on the first shielding layer and the plurality of first silicone rubber materials, wherein the composite layer includes a graphene layer and a metal layer; the composite layer is patterned to form a second circuit layer; a second shielding layer is formed on the second circuit layer, wherein the second shielding layer includes a second low-frequency shielding layer and a second high-frequency shielding layer; a plurality of second openings are formed on the second shielding layer to expose the second circuit layer; a plurality of second silicone rubber materials are filled in the plurality of second openings; and a plurality of second conductive blind vias are formed in the plurality of second silicone rubber materials.

According to an embodiment of the present invention, before forming the second shielding layer, the method further comprises forming a plurality of conductive vias in the second circuit layer, wherein the plurality of conductive vias are electrically connected to the plurality of first conductive blind vias respectively.

According to an embodiment of the present invention, the step of forming the composite layer includes forming an insulating layer on the first shielding layer and the plurality of first silicone rubber materials; forming the graphene layer on the insulating layer; and forming the metal layer on the graphene layer.

According to an embodiment of the present invention, the method further comprises forming at least one third opening on the second shielding layer and between the plurality of second openings to expose the insulating layer; and filling a third silicone rubber material into the at least one third opening.

According to an embodiment of the present invention, the step of patterning the composite layer includes removing the metal layer; and patterning the graphene layer using plasma.

According to an embodiment of the present invention, before placing the electronic component in the groove, the method further comprises forming an adhesive layer at the bottom of the groove; and placing the electronic component on the adhesive layer.

According to one embodiment of the present invention, the step of forming the first shielding layer includes forming a first dielectric layer on the insulating substrate and the electronic element; forming the first low-frequency shielding layer on the first dielectric layer; and forming the first high-frequency shielding layer on the first low-frequency shielding layer.

According to one embodiment of the present invention, the step of forming the second shielding layer is to form a second dielectric layer on the second circuit layer; to form the second low-frequency shielding layer on the second dielectric layer; to form the second high-frequency shielding layer on the second low-frequency shielding layer; and to form a third dielectric layer on the second high-frequency shielding layer.

According to another aspect of the present invention, a circuit board is provided, which includes an insulating substrate having a groove, an electronic component disposed in the groove, a first circuit layer disposed on the top surface of the electronic component, a first shielding layer disposed on the insulating substrate and the electronic component, a plurality of first silicone rubber materials disposed in the first shielding layer, a plurality of first silicone rubber materials disposed in the first shielding layer, a second circuit layer disposed on the first shielding layer, a second shielding layer disposed on the second circuit layer, a plurality of second silicone rubber materials disposed in the second shielding layer, and a plurality of second conductive blind vias disposed in the plurality of second conductive blind vias. The first shielding layer overlaps with the electronic component. The first conductive blind via is electrically connected to the first circuit layer, and the second conductive blind via is electrically connected to the second circuit layer.

According to an embodiment of the present invention, the first shielding layer includes a first dielectric layer disposed on the insulating substrate and the electronic element, a first low-frequency shielding layer disposed on the first dielectric layer, and a first high-frequency shielding layer disposed on the first low-frequency shielding layer.

According to one embodiment of the present invention, the second shielding layer includes a second dielectric layer disposed on the second circuit layer, a second dielectric layer disposed on the second circuit layer, a second high-frequency shielding layer disposed on the second low-frequency shielding layer, and a third dielectric layer disposed on the second high-frequency shielding layer.

According to an embodiment of the present invention, the circuit board further comprises a plurality of conductive vias disposed in the second circuit layer, wherein the plurality of conductive vias are electrically connected to the plurality of first conductive blind vias respectively.

According to an embodiment of the present invention, the second circuit layer includes at least one of graphene and copper.

According to an embodiment of the present invention, the circuit board further includes a third silicone rubber material disposed in the second shielding layer and between the plurality of second silicone rubber materials.

By applying the circuit board and the manufacturing method thereof of the present invention, silicone rubber material is used as electromagnetic radiation shielding material, and a low-frequency shielding layer and a high-frequency shielding layer are combined to more effectively shield electromagnetic radiation in the signal output path.

The present invention provides many different embodiments or examples to implement different features of the invention. The specific examples of components and configurations described below are intended to simplify the present invention. These are of course only examples and are not intended to be limiting. For example, a description of a first feature formed on or above a second feature includes embodiments in which the first feature and the second feature are in direct contact, and also includes embodiments in which other features are formed between the first feature and the second feature, so that the first feature and the second feature are not in direct contact. In addition, the present invention repeats component symbols and/or letters in various specific examples. The purpose of this repetition is to simplify and clarify the description and does not indicate a relationship between the various discussed embodiments and/or configurations.

Furthermore, spatially relative terms, such as "beneath," "below," "lower," "above," "upper," etc., are used to facilitate description of the relationship of a part or feature to other parts or features depicted in the drawings. Spatially relative terms include different orientations of the component when in use or operation in addition to the orientation depicted in the drawings. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used in the present invention can be interpreted in this manner.

As used in the present invention, "around", "about", "approximately" or "substantially" generally means within 20%, within 10%, or within 5% of the stated value or range.

It is known that a common method for shielding electromagnetic radiation is to use shielding conductive materials to seal the outside of a circuit board. Shielding conductive materials are mostly metals, but they are expensive and difficult to process. Therefore, the present invention provides a circuit board and a manufacturing method thereof, which uses silicone rubber material as an electromagnetic radiation shielding material and combines a low-frequency shielding layer and a high-frequency shielding layer to more effectively shield electromagnetic radiation in the signal output path.

1A to 1M are cross-sectional views of intermediate stages of the manufacturing process of a circuit board 100 according to some embodiments of the present invention. First, referring to FIG. 1A , an insulating substrate 110 is provided, and a groove R1 is formed in the insulating substrate 110. Next, referring to FIG. 1B , an electronic component 120 is placed in the groove R1, and a first circuit layer 125 is formed on the electronic component 120. In some embodiments, an adhesive layer 115 is formed on the bottom of the groove R1, and the electronic component 120 is placed on the adhesive layer 115.

Referring to FIG. 1C , the first shielding layer 130 is formed on the insulating substrate 110 and the electronic element 120. In other words, the first shielding layer 130 overlaps with the electronic element 120. In some embodiments, the first shielding layer 130 includes a first dielectric layer 135, a first low-frequency shielding layer 140, and a first high-frequency shielding layer 145. Therefore, the step of forming the first shielding layer 130 includes forming the first dielectric layer 135 on the insulating substrate 110 and the electronic element 120, then forming the first low-frequency shielding layer 140 on the first dielectric layer 135, and then forming the first high-frequency shielding layer 145 on the first low-frequency shielding layer 140. It should be noted that the first dielectric layer 135 is further partially formed in the groove R1 (see FIG. 1B ) and on the adhesive layer 115 .

In some embodiments, the first dielectric layer 135 includes an insulating line and a mask layer to protect the first line layer 125. In some embodiments, the first low-frequency shielding layer 140 includes a carbon fiber composite material to shield electromagnetic radiation in the low frequency band. In some embodiments, the first high-frequency shielding layer 145 includes an alloy grid, which can be nickel, chromium, copper, silver, gold, and any combination of the foregoing metal materials to shield electromagnetic radiation in the high frequency band. In some embodiments, the first high-frequency shielding layer 145 can be formed by chemical plating, physical vapor deposition (PVD) (such as evaporation or sputtering), chemical vapor deposition (CVD) or electroplating.

Referring to FIG. 1D , a first opening O1 is formed in the first shielding layer 130 . In some embodiments, the first opening O1 passes through the first high-frequency shielding layer 145 and the first dielectric layer 135 to expose the first circuit layer 125 . Next, referring to FIG. 1E , the first silicone rubber material 150 is filled in the first opening O1 (refer to FIG. 1D ). In some embodiments, the bottom of the first silicone rubber material 150 contacts the first circuit layer 125 , and the top of the first silicone rubber material 150 is flush with the top surface 145T of the first high-frequency shielding layer 145 . The first silicone rubber material 150 is mainly used to shield electromagnetic waves. Compared with the conventional shielding conductive material (ie, metal), the silicone rubber composite material included in the first silicone rubber material 150 can not only effectively suppress electromagnetic radiation and prevent external electromagnetic radiation from interfering with the circuit board, but also reduce material costs.

Referring to FIG. 1F , a hole is drilled in the first silicone rubber material 150 to form an opening (not shown). It should be noted that the width of the aforementioned opening is smaller than the first opening O1. Then, a conductive material is filled into the aforementioned opening to form a first conductive blind via 155 in the first silicone rubber material 150 and electrically connected to the first circuit layer 125. In some embodiments, the first conductive blind via 155 can be formed by filling the conductive material using electroplating and chemical plating methods. In a specific example, the first conductive blind via 155 includes copper.

1G , a composite layer 165 is formed on the first shielding layer 130 and the first silicone rubber material 150. In some embodiments, the composite layer 165 includes an insulating layer 160, a graphene layer 161, and a metal layer 163. Therefore, the step of forming the composite layer 165 includes forming the insulating layer 160 on the first shielding layer 130 and the first silicone rubber material 150, then forming the graphene layer 161 on the insulating layer 160, and then forming the metal layer 163 on the graphene layer 161. In a specific example, the metal layer 163 includes copper.

1H to 1M are used as an example to illustrate the production of a circuit board 100 having a low-frequency signal line. Referring to FIG. 1H , the composite layer 165 (refer to FIG. 1G ) is patterned to form a second circuit layer 170. First, the metal layer 163 (refer to FIG. 1G ) is exposed and developed to form a metal circuit layer 168 on the graphene layer 161 (refer to FIG. 1G ). Then, the graphene layer 161 is etched by oxygen plasma to form a graphene circuit layer 166 on the insulating layer 160. In some embodiments, as shown in FIG. 1H , the second circuit layer 170 includes a metal circuit layer 168 and a graphene circuit layer 166.

Referring to FIG. 1I , the second circuit layer 170 and the insulating layer 160 may be drilled to form an opening (not shown) extending from the second circuit layer 170 to the insulating layer 160, wherein the opening may partially expose one end of the first conductive blind via 155. Then, a conductive material is filled into the opening to form a conductive via 175 passing through the second circuit layer 170 and the insulating layer 160, and electrically connected to the first conductive blind via 155. In some embodiments, the conductive via 175 may be formed by filling the conductive material using electroplating and chemical plating methods. In a specific example, the conductive via 175 includes copper.

1J , a second shielding layer 180 is formed on the second circuit layer 170. In some embodiments, the second shielding layer 180 includes a second dielectric layer 182, a second low-frequency shielding layer 184, a second high-frequency shielding layer 186, and a third dielectric layer 188. Therefore, the step of forming the second shielding layer 180 includes first forming the second dielectric layer 182 on the second circuit layer 170 and the insulating layer 160, then forming the second low-frequency shielding layer 184 on the second dielectric layer 182, forming the second high-frequency shielding layer 186 on the second low-frequency shielding layer 184, and then forming the third dielectric layer 188 on the second high-frequency shielding layer 186.

In some embodiments, the second dielectric layer 182 includes an insulating circuit and a mask layer to protect the first circuit layer 125. In some embodiments, the second low-frequency shielding layer 184 includes a carbon fiber composite material to shield electromagnetic radiation in the low frequency band. In some embodiments, the second high-frequency shielding layer 186 includes an alloy grid, which can be nickel, chromium, copper, silver, gold, and any combination of the aforementioned metal materials to shield electromagnetic radiation in the high frequency band. In some embodiments, the second high-frequency shielding layer 186 can be formed by chemical plating, physical vapor deposition (PVD) (such as evaporation or sputtering), chemical vapor deposition (CVD) or electroplating. The third dielectric layer 188 is used to protect the second high frequency shielding layer 186 and the second low frequency shielding layer 184.

Referring to FIG. 1K , a second opening O2 is formed in the second shielding layer 180 to expose the metal wiring layer 168 of the second wiring layer 170. In some embodiments, the second opening O2 extends from the third dielectric layer 188 to a portion of the second dielectric layer 182. In some embodiments, a third opening O3 may be selectively formed to expose the insulating layer 160. In some embodiments, the third opening O3 is between at least two second openings O2. In some embodiments, the third opening O3 extends from the third dielectric layer 188 to the top of the insulating layer 160 and exposes the sidewall of the second wiring layer 170. Therefore, the depth of the third opening O3 is greater than the depth of the second opening O2.

Referring to FIG. 1L , the second silicone rubber material 190 is filled in the second opening O2 (see FIG. 1K ). In some embodiments, the bottom of the second silicone rubber material 190 contacts the second circuit layer 170 (or the metal circuit layer 168 ), and the top of the second silicone rubber material 190 is flush with the top surface 188T of the third dielectric layer 188 . In some embodiments in which the third opening O3 (see FIG. 1K ) is formed, the third silicone rubber material 192 may be filled in the third opening O3 . In this embodiment, the bottom of the third silicone rubber material 192 contacts the insulating layer 160, and the top of the third silicone rubber material 192 is flush with the top surface 188T of the third dielectric layer 188. In some embodiments, the first silicone rubber material 150, the second silicone rubber material 190, and the third silicone rubber material 192 include the same silicone rubber composite material. Therefore, the second silicone rubber material 190 and the third silicone rubber material 192 are also used to shield electromagnetic waves.

Referring to FIG. 1M , a second conductive blind via 195 is formed in the second silicone rubber material 190 to electrically connect the second circuit layer 170 (or metal circuit layer 168). In some embodiments, a pad 195A may be formed on the top of the second conductive blind via 195. In some embodiments, forming the second conductive blind via 195 includes first forming an opening (not shown) in the second silicone rubber material 190, and then filling (e.g., electroplating) a conductive material into the aforementioned opening. It should be noted that no conductive blind via is formed in the third silicone rubber material 192. As shown in FIG. 1M , the circuit board 100 manufactured according to the above steps mainly uses the metal circuit layer 168 to transmit low-frequency signals.

Please refer to Figures 2A to 2C, which are cross-sectional views of intermediate stages of the manufacturing process of the circuit board 200 according to some embodiments of the present invention. Figures 2A to 2C are for manufacturing a circuit board 200 having a high-frequency signal line. The manufacturing process of the circuit board 200 below can be described starting from the structure of Figure 1G. Please refer to Figure 2A, and the entire metal layer 163 is removed. In other words, the composite layer 165 in Figure 1G may not include the metal layer 163, and the step of removing the metal layer 163 may be omitted. Therefore, the structure shown in Figure 2A includes an insulating substrate 110, an electronic component 120 on the insulating substrate 110, a first circuit layer 125 on the electronic component 120, a first shielding layer 130 on the insulating substrate 110 and the electronic component 120, a first silicone rubber material 150 in the first shielding layer 130, a first conductive blind via 155 in the first silicone rubber material 150, an insulating layer 160 on the first shielding layer 130, and a graphene layer 161 on the insulating layer 160.

2B , the graphene layer 161 (see FIG. 2A ) is patterned to form a second circuit layer 270 . In some embodiments, the graphene layer 161 is etched by oxygen plasma to form the second circuit layer (or graphene circuit layer) 270 on the insulating layer 160 .

Next, please refer to FIG. 2C , and the structure of FIG. 2B is subjected to steps similar to those of FIG. 1I to FIG. 1L , i.e., forming a conductive hole 175 through the second circuit layer 270 and the insulating layer 160; forming a second shielding layer 180 on the second circuit layer 270; and forming a second silicone rubber material 190 and a third silicone rubber material 192. Then, a second conductive blind hole 195 is formed in the second silicone rubber material 190 to electrically connect the second circuit layer (or graphene circuit layer) 270, and a circuit board 200 as shown in FIG. 2C is obtained. The circuit board 200 obtained according to the above steps mainly uses the graphene circuit layer (i.e., the second circuit layer 270) to transmit high-frequency signals.

Please refer to Figures 3A to 3C, which are cross-sectional views of intermediate stages of the manufacturing process of the circuit board 300 according to some embodiments of the present invention. Figures 3A to 3C are for manufacturing a circuit board 300 having a high-frequency signal line and a low-frequency signal line. The manufacturing process of the circuit board 300 can be described below starting from the structure of Figure 1G. Please refer to Figure 3A, and the metal layer 163 (refer to Figure 1G) is patterned by exposure and development to form a metal wiring layer 368. It should be noted that the pattern of the metal wiring layer 368 is different from that of the metal wiring layer 168, and the metal wiring layer 368 is only above a portion of the first wiring layer 125, and is not located above other portions of the first wiring layer 125.

The structure shown in FIG. 3A includes an insulating substrate 110, an electronic component 120 on the insulating substrate 110, a first circuit layer 125 on the electronic component 120, a first shielding layer 130 on the insulating substrate 110 and the electronic component 120, a first silicone rubber material 150 in the first shielding layer 130, a first conductive blind via 155 in the first silicone rubber material 150, an insulating layer 160 on the first shielding layer 130, a graphene layer 161 on the insulating layer 160, and a metal circuit layer 368 on the graphene layer 161.

Referring to FIG. 3B , the graphene layer 161 (refer to FIG. 3A ) is patterned to form a graphene wiring layer 366. In some embodiments, the graphene layer 161 is etched by oxygen plasma to form the graphene wiring layer 366. In some embodiments, as shown in FIG. 3B , the second wiring layer 370 includes a metal wiring layer 368 and a graphene wiring layer 366. Compared to the graphene wiring layer 166 of the second wiring layer 170 being completely covered by the metal wiring layer 168, a portion of the graphene wiring layer 366 in the second wiring layer 370 shown in FIG. 3B is not covered by the metal wiring layer 368.

Next, please refer to FIG. 3C , and the structure of FIG. 3B is subjected to steps similar to those of FIG. 1I to FIG. 1L , that is, a conductive hole 175 is formed to pass through the second circuit layer 370 and the insulating layer 160; a second shielding layer 180 is formed on the second circuit layer 370; and a second silicone rubber material 190 and a third silicone rubber material 192 are formed. Then, a second conductive blind hole 195 is formed in the second silicone rubber material 190 to electrically connect the second circuit layer 370, and a circuit board 300 as shown in FIG. 3C is obtained. The circuit board 300 obtained according to the above steps can mainly use the graphene circuit layer 366 to transmit high-frequency signals and the metal circuit layer 368 to transmit low-frequency signals.

As described above, the present invention provides a circuit board and a manufacturing method thereof, which utilizes silicone rubber material as electromagnetic radiation shielding material, arranges the silicone rubber material around the conductive blind hole, and combines a low-frequency shielding layer and a high-frequency shielding layer to shield the electromagnetic radiation generated by each line signal.

Although the present invention has been disclosed as above with several embodiments, they are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the scope of the attached patent application.

100: Circuit board 110: Insulating substrate 115: Adhesive layer 120: Electronic component 125: First circuit layer 130: First shielding layer 135: First dielectric layer 140: First low-frequency shielding layer 145: First high-frequency shielding layer 145T: Top surface 150: First silicone rubber material 155: First conductive blind hole 160: Insulating layer 161: Graphene layer 163: Metal layer 165: Composite layer 166: Graphene circuit layer 168: Metal circuit layer 170: Second circuit layer 175: Conductive hole 180: Second shielding layer 182: Second dielectric layer 184: Second low-frequency shielding layer 186: Second high-frequency shielding layer 188: Third dielectric layer 188T: Top surface 190: Second silicone rubber material 192: Third silicone rubber material 195: Second conductive blind hole 195A: Pad 200: Circuit board 270: Second circuit layer 300: Circuit board 366: Graphene circuit layer 368: Metal circuit layer 370: Second circuit layer O1: First opening O2: Second opening O3: Third opening R1: Groove

The present invention is best understood by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, for the sake of clarity of discussion, the sizes of many features may be arbitrarily scaled. [Figures 1A] to 1M] illustrate cross-sectional views of intermediate stages of the manufacturing process of circuit boards according to some embodiments of the present invention. [Figures 2A] to 2C] illustrate cross-sectional views of intermediate stages of the manufacturing process of circuit boards according to other embodiments of the present invention. [Figures 3A] to 3C] illustrate cross-sectional views of intermediate stages of the manufacturing process of circuit boards according to other embodiments of the present invention.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

100: Circuit board

110: Insulating substrate

120: Electronic components

125: First circuit layer

135: First dielectric layer

140: First low-frequency shielding layer

145: The first high-frequency shielding layer

150: The first silicone rubber material

155: First conductive blind hole

160: Insulation layer

166: Graphene circuit layer

168: Metal circuit layer

170: Second circuit layer

180: Second shielding layer

182: Second dielectric layer

184: Second low-frequency shielding layer

186: Second high frequency shielding layer

188: The third medium layer

190: Second silicone rubber material

192: The third silicone rubber material

195: Second conductive blind hole

195A: Pad

Claims (14)

A method for manufacturing a circuit board, comprising: forming a groove in an insulating substrate; placing an electronic component in the groove, wherein the electronic component includes a first circuit layer; forming a first shielding layer on the insulating substrate and the electronic component, wherein the first shielding layer includes a first low-frequency shielding layer and a first high-frequency shielding layer; forming a plurality of first openings in the first shielding layer to expose the first circuit layer; filling a plurality of first silicone rubber materials in the plurality of first openings; forming a plurality of first conductive blind holes in the plurality of first silicone rubber materials, wherein the plurality of first conductive blind holes are electrically connected to the first circuit layer; Forming a composite layer on the first shielding layer and the plurality of first silicone rubber materials, wherein the composite layer includes a graphene layer and a metal layer; Patterning the composite layer to form a second circuit layer; Forming a second shielding layer on the second circuit layer, wherein the second shielding layer includes a second low-frequency shielding layer and a second high-frequency shielding layer; Forming a plurality of second openings on the second shielding layer to expose the second circuit layer; Filling a plurality of second silicone rubber materials in the plurality of second openings; and Forming a plurality of second conductive blind vias in the plurality of second silicone rubber materials. The method for manufacturing a circuit board as described in claim 1, wherein before forming the second shielding layer, it further comprises: Forming a plurality of conductive holes in the second circuit layer, wherein the plurality of conductive holes are electrically connected to the plurality of first conductive blind holes respectively. The method for manufacturing a circuit board as described in claim 1, wherein the step of forming the composite layer includes: forming an insulating layer on the first shielding layer and the plurality of first silicone rubber materials; forming the graphene layer on the insulating layer; and forming the metal layer on the graphene layer. The method for manufacturing a circuit board as described in claim 3 further comprises: forming at least one third opening on the second shielding layer and between the plurality of second openings to expose the insulating layer; and filling a third silicone rubber material in the at least one third opening. The method for manufacturing a circuit board as described in claim 1, wherein the step of patterning the composite layer comprises: removing the metal layer; and patterning the graphene layer using plasma. The method for manufacturing a circuit board as described in claim 1, wherein before placing the electronic component in the groove, it further comprises: forming an adhesive layer at a bottom of the groove; and placing the electronic component on the adhesive layer. The method for manufacturing a circuit board as described in claim 1, wherein the step of forming the first shielding layer comprises: forming a first dielectric layer on the insulating substrate and the electronic component; forming the first low-frequency shielding layer on the first dielectric layer; and forming the first high-frequency shielding layer on the first low-frequency shielding layer. The method for manufacturing a circuit board as described in claim 1, wherein the step of forming the second shielding layer comprises: forming a second dielectric layer on the second circuit layer; forming the second low-frequency shielding layer on the second dielectric layer; forming the second high-frequency shielding layer on the second low-frequency shielding layer; and forming a third dielectric layer on the second high-frequency shielding layer. A circuit board comprises: an insulating substrate having a groove; an electronic component disposed in the groove; a first circuit layer disposed on a top surface of the electronic component; a first shielding layer disposed on the insulating substrate and the electronic component, wherein the first shielding layer overlaps the electronic component; a plurality of first silicone rubber materials disposed in the first shielding layer; a plurality of first conductive blind holes disposed in the plurality of first silicone rubber materials to electrically connect the first circuit layer; a second circuit layer disposed on the first shielding layer; a second shielding layer disposed on the second circuit layer; a plurality of second silicone rubber materials disposed in the second shielding layer; and A plurality of second conductive blind vias are arranged in the plurality of second conductive blind vias to electrically connect the second circuit layer. A circuit board as described in claim 9, wherein the first shielding layer comprises: a first dielectric layer disposed on the insulating substrate and the electronic component; a first low-frequency shielding layer disposed on the first dielectric layer; and a first high-frequency shielding layer disposed on the first low-frequency shielding layer. A circuit board as described in claim 9, wherein the second shielding layer comprises: a second dielectric layer disposed on the second circuit layer; a second low-frequency shielding layer disposed on the second dielectric layer; a second high-frequency shielding layer disposed on the second low-frequency shielding layer; and a third dielectric layer disposed on the second high-frequency shielding layer. The circuit board as described in claim 9 further comprises: A plurality of conductive vias disposed in the second circuit layer, wherein the plurality of conductive vias are electrically connected to the plurality of first conductive blind vias respectively. A circuit board as described in claim 9, wherein the second circuit layer includes at least one of graphene and copper. The circuit board as described in claim 9 further comprises: A third silicone rubber material disposed in the second shielding layer and between the plurality of second silicone rubber materials.

Images