Circuit board assembly and manufacturing method thereof

Abstract

The invention provides a circuit board assembly and a manufacturing method thereof. The circuit board assembly comprises a flexible circuit board, a plurality of electronic elements, a circuit board and a plurality of cooling fins. The flexible circuit board comprises a first circuit layer and a dielectric layer. The dielectric layer has a cavity. The first circuit layer covers the cavity. The plurality of electronic components are arranged in the flexible circuit board and are electrically connected with the first circuit layer. The circuit board and the flexible circuit board are stacked, and the circuit board comprises a second circuit layer and is provided with an opening. And the opening exposes a part of the flexible circuit board. The plurality of electronic elements are located between the second circuit layer and the flexible circuit board. The circuit board is located between the plurality of radiating fins and the plurality of electronic components. Heat energy generated by electronic elements in the circuit board assembly can be conducted to the cooling fins for heat dissipation, and therefore the heat dissipation effect is improved.

Description

Technical Field

[0001] This application relates to a circuit board assembly and a method for manufacturing the same. Background Technology

[0002] In recent years, portable electronic products such as laptops, smartphones, tablets, and wearable devices have become increasingly popular. As portable electronic products move towards miniaturization and multifunctionality, the integration density of internal components also increases. Therefore, heat dissipation is becoming increasingly important for portable electronic products. Furthermore, portable electronic products sometimes need to be flexible to ensure comfort for wearers. Summary of the Invention

[0003] At least one embodiment of this application provides a circuit board assembly and a method for manufacturing the same. Heat generated by electronic components within the circuit board assembly can be conducted to a heat sink for dissipation, thereby improving heat dissipation performance.

[0004] The circuit board assembly provided in at least one embodiment of this application includes a flexible circuit board, multiple electronic components, a first circuit board, and multiple heat sinks. The flexible circuit board includes a first wiring layer and a first dielectric layer. The first dielectric layer has a cavity. The first wiring layer has a transmission section. The transmission section covers the cavity. Multiple electronic components are disposed within the flexible circuit board and electrically connected to the first wiring layer. The cavity is located between the multiple electronic components, and the multiple electronic components are electrically connected to each other via the transmission section. The first circuit board is stacked with the flexible circuit board and includes a second wiring layer, having a first opening. The first opening exposes a portion of the flexible circuit board, and the vertical projection of the first opening onto the flexible circuit board overlaps with the vertical projection of the cavity onto the flexible circuit board. Multiple electronic components are located between the second wiring layer and the flexible circuit board. The second wiring layer has a heat-conducting section and at least one trace. The heat-conducting section and the at least one trace are separated. Multiple heat sinks are disposed on the heat-conducting section of the second wiring layer and are respectively stacked on the multiple electronic components. The first circuit board is located between the multiple heat sinks and the multiple electronic components.

[0005] In at least one embodiment of this application, the circuit board assembly further includes a plurality of conductive structures. The plurality of conductive structures are disposed within the flexible circuit board. Each conductive structure extends from the first circuit layer through the first dielectric layer and to one of the electronic components, thereby electrically connecting the first circuit layer and the one of the electronic components.

[0006] In at least one embodiment of this application, the materials of the plurality of conductive structures include epoxy resin and metal. The metal is distributed within the epoxy resin.

[0007] In at least one embodiment of this application, the circuit board assembly further includes a plurality of thermally conductive structures. The plurality of thermally conductive structures are disposed within the first circuit board. Each thermally conductive structure extends from one of the heat sinks through the second circuit layer and to one of the electronic components, thereby connecting the heat sink, the second circuit layer, and the electronic component.

[0008] In at least one embodiment of this application, the materials of the plurality of thermally conductive structures include epoxy resin and metal. The metal is distributed within the epoxy resin.

[0009] In at least one embodiment of this application, the circuit board assembly further includes a second circuit board. The second circuit board is stacked with the flexible circuit board and has a second opening. The second opening exposes a portion of the flexible circuit board, and the vertical projection of the second opening onto the flexible circuit board overlaps with the vertical projection of the cavity onto the flexible circuit board. The flexible circuit board is located between the first circuit board and the second circuit board.

[0010] In at least one embodiment of this application, the circuit board assembly further includes multiple layers of solder resist. The multiple layers of solder resist cover the first circuit board and the second circuit board respectively, and expose portions of the flexible circuit board and multiple heat sinks.

[0011] The method for manufacturing a circuit board assembly provided in at least one embodiment of this application includes: providing a flexible circuit board having a cavity; disposing of a plurality of electronic components within the flexible circuit board, wherein the flexible circuit board exposes the plurality of electronic components, and the cavity is located between the plurality of electronic components; providing a substrate; after disposing of the plurality of electronic components within the flexible circuit board, bonding the substrate and the flexible circuit board, wherein the substrate covers the plurality of electronic components; after bonding the substrate and the flexible circuit board, forming an opening in the substrate, wherein the opening exposes a portion of the flexible circuit board, and the vertical projection of the opening on the flexible circuit board overlaps with the vertical projection of the cavity on the flexible circuit board; after forming the opening, patterning a metal layer of the substrate to form a circuit board; and disposing of a plurality of heat sinks on the circuit board, wherein the circuit board is located between the plurality of heat sinks and the plurality of electronic components.

[0012] In at least one embodiment of this application, providing a flexible circuit board includes: providing a first flexible substrate, wherein the first flexible substrate includes a first metal layer and a first dielectric layer; forming a groove in the first dielectric layer, wherein the groove exposes the first metal layer; providing a second flexible substrate; after forming the groove, bonding the first flexible substrate and the second flexible substrate, wherein the second flexible substrate covers the groove, such that the groove forms a cavity; and after forming the cavity, patterning the first metal layer to form a first circuit layer, such that the first flexible substrate and the second flexible substrate form a flexible circuit board.

[0013] In at least one embodiment of this application, the manufacturing method further includes: after bonding a substrate and a flexible circuit board, forming a plurality of through holes in the substrate, wherein the plurality of through holes expose portions of a plurality of electronic components; disposing a thermally conductive material in the plurality of through holes such that the thermally conductive material contacts the plurality of electronic components; and after disposing the thermally conductive material, heating the thermally conductive material to form a plurality of thermally conductive structures.

[0014] Based on the above, in the circuit board assembly disclosed in the above embodiments, the heat generated by the electronic components can be conducted to the heat sink for heat dissipation, thereby improving the heat dissipation effect. In addition, the circuit board assembly has cavities, which also increases the flexibility of the circuit board assembly. Attached Figure Description

[0015] To gain a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:

[0016] Figure 1 This is a partial cross-sectional schematic diagram of a circuit board assembly according to at least one embodiment of this application;

[0017] Figure 2A yes Figure 1 A partial cross-sectional schematic diagram of a method for manufacturing a circuit board assembly, which provides a flexible substrate.

[0018] Figure 2B yes Figure 1 A cross-sectional view of a portion forming multiple grooves in a method for manufacturing a circuit board assembly;

[0019] Figure 2C yes Figure 1 A partial cross-sectional schematic diagram of the flexible substrate in the manufacturing method of the circuit board assembly.

[0020] Figure 2D yes Figure 1 A partial cross-sectional schematic diagram of the process for manufacturing a flexible circuit board assembly.

[0021] Figure 3 yes Figure 1 A partial cross-sectional view of a method for manufacturing a circuit board assembly in which multiple electronic components are arranged.

[0022] Figure 4 yes Figure 1 A partial cross-sectional view of the conductive structure in the manufacturing method of the circuit board assembly.

[0023] Figure 5 yes Figure 1 A partial cross-sectional schematic diagram of the bonding substrate and flexible circuit board in the manufacturing method of the circuit board assembly.

[0024] Figure 6 yes Figure 1A partial cross-sectional schematic diagram of the process of forming multiple through holes and removing metal layers in the manufacturing method of a circuit board assembly;

[0025] Figure 7 yes Figure 1 A partial cross-sectional schematic diagram of the process of forming an opening, setting a heat-conducting structure, and forming a circuit layer in the manufacturing method of a circuit board assembly.

[0026] Figure 8 yes Figure 1 A partial cross-sectional view of the method for manufacturing a circuit board assembly, including the application of a solder resist layer; and

[0027] Figure 9 yes Figure 1 A cross-sectional view of the portion forming the groove in the manufacturing method of the circuit board assembly. Detailed Implementation

[0028] In the following text, to clearly present the technical features of this application, the dimensions (e.g., length, width, thickness, and depth) of the elements (e.g., layers, films, substrates, and regions) in the accompanying drawings will be enlarged proportionally, and the number of some elements may be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of elements in the drawings or the size and shape of the elements, but should cover the dimensions, shapes, and deviations from both caused by actual manufacturing processes and / or tolerances. For example, a flat surface shown in the drawings may have rough and / or non-linear characteristics, and an acute angle shown in the drawings may be rounded. Therefore, the elements presented in the accompanying drawings are primarily for illustration and are not intended to precisely depict the actual shape of the elements, nor are they intended to limit the claims of this application. Furthermore, some drawings introduce a Cartesian coordinate system (a rectangular coordinate system with three axes: X, Y, and Z) to illustrate the technical features of this application.

[0029] Secondly, the terms "approximately," "approximately," or "substantially" used in this document not only cover explicitly stated numerical values ​​and ranges, but also the permissible deviation range understood by those skilled in the art. This deviation range can be determined by errors that arise during measurement, such as those caused by limitations of the measurement system or process conditions. Furthermore, "approximately" can indicate a deviation within one or more standard deviations of the aforementioned numerical values, such as ±30%, ±20%, ±10%, or ±5%. The terms "approximately," "approximately," or "substantially" used in this document can be chosen based on optical, etching, mechanical, or other properties to select an acceptable deviation range or standard deviation, and do not apply a single standard deviation to all optical, etching, mechanical, and other properties. Additionally, for clarity in the following embodiments, components with the same or similar functions are indicated by the same designation.

[0030] Figure 1 This is a partial cross-sectional schematic diagram of a circuit board assembly 100 according to at least one embodiment of this application. (See also...) Figure 1 The circuit board assembly 100 includes a flexible circuit board 110, multiple electronic components 121 and 122, multiple conductive structures 130, circuit boards 140 and 150, multiple heat sinks 161 and 162, multiple thermally conductive structures 170, and multiple solder resist layers 181 and 182. The circuit board assembly 100 can be used in electronic products that require bending, but is not limited thereto.

[0031] The flexible printed circuit board 110 comprises multiple circuit layers 111-113, multiple dielectric layers 114 and 115, and multiple cover layers 116 and 117. The circuit layers 111-113, dielectric layers 114 and 115, and cover layers 116 and 117 are stacked. Figure 1 In the example, the flexible circuit board 110 includes three circuit layers 111-113, two dielectric layers 114 and 115, and two cover layers 116 and 117. The dielectric layer 114 is sandwiched between adjacent circuit layers 111 and 112. The dielectric layer 115 is sandwiched between adjacent circuit layers 112 and 113.

[0032] Furthermore, the circuit layer 111 has a transmission section 111a. The dielectric layer 114 and the circuit layer 112 have cavities 118. The cavity 118 extends through the dielectric layer 114 and the circuit layer 112 and extends along the Y direction. The transmission section 111a covers the cavity 118. In other words, the vertical projection of the transmission section 111a on the flexible circuit board 110 overlaps with the vertical projection of the cavity 118 on the flexible circuit board 110. That is, the projection of the transmission section 111a in the Z direction overlaps with the projection of the cavity 118 in the Z direction.

[0033] Cover layers 116 and 117 are exposed on the upper and lower surfaces of the flexible circuit board 110, respectively. Cover layer 116 can contact the surface of circuit layer 111 and the surface of the exposed dielectric layer 114 of circuit layer 111. Cover layer 117 can contact the surface of circuit layer 113 and the surface of the exposed dielectric layer 115 of circuit layer 113.

[0034] The materials for circuit layers 111-113 can be copper. The materials for dielectric layers 114 and 115 can be polyimide (PI), modified polyimide (MPI), liquid crystal polymer (LCP), or polytetrafluoroethylene (PTFE). The materials for capping layers 116 and 117 can be polyimide.

[0035] Electronic component 121 may be a wafer or an active component. Electronic component 122 may be a wafer or an active component. Electronic components 121 and 122 are disposed within the flexible circuit board 110. For example, electronic components 121 and 122 are disposed between circuit layer 112, dielectric layer 115, circuit layer 113 and cover layer 117, and cover layer 117 exposes the surfaces of electronic components 121 and 122. Cavity 118 is located between electronic components 121 and 122.

[0036] Multiple conductive structures 130 are disposed within the flexible circuit board 110. The conductive structures 130 may be columnar in shape. Each conductive structure 130 extends from the circuit layer 111 through the dielectric layer 114 and to the electronic component 121 or 122, electrically connecting the circuit layer 111 and the electronic component 121 or 122. A cover layer 116 exposes the top surface of the conductive structure 130. The electronic components 121 and 122 can be electrically connected to the circuit layer 111 via the conductive structure 130 and electrically connected to each other via the transmission section 111a to transmit signals. The material of the conductive structure 130 may include epoxy resin and metal. The metal is distributed within the epoxy resin. The metal may include silver and / or copper. The epoxy resin can bond the electronic components 121, 122 and the circuit layer 111, while the metal can electrically conduct the electronic components 121, 122 and the circuit layer 111.

[0037] The circuit board 140 includes a wiring layer 141 and an adhesive layer 142, and the wiring layer 141 and the adhesive layer 142 are stacked. The wiring layer 141 has a heat-conducting portion 141a and at least one trace 141b. Figure 1 In the example, circuit layer 141 has multiple traces 141b. Circuit board 140 is stacked with flexible circuit board 110. Adhesive layer 142 is disposed on cover layer 117 and located between cover layer 117 and circuit layer 141. Adhesive layer 142 covers the surfaces of electronic components 121 and 122. Circuit board 140 has an opening 143. Opening 143 exposes a portion of cover layer 117 of flexible circuit board 110. Further, the vertical projection of opening 143 on flexible circuit board 110 overlaps with the vertical projection of cavity 118 on flexible circuit board 110. That is, the projection of opening 143 in direction Z overlaps with the projection of cavity 118 in direction Z. The material of circuit layer 141 may be copper. The material of adhesive layer 142 may include glass fiber and epoxy resin.

[0038] Circuit board 150 includes an adhesive layer 151. Circuit board 150 is stacked with flexible circuit board 110 and circuit board 140. Flexible circuit board 110 is located between circuit boards 140 and 150. Adhesive layer 151 is disposed on cover layer 116 and covers the top surface of conductive structure 130. Circuit board 150 has an opening 152. Opening 152 exposes a portion of cover layer 116 of flexible circuit board 110. The vertical projection of opening 152 on flexible circuit board 110 overlaps with the vertical projection of cavity 118 on flexible circuit board 110. That is, the projection of opening 152 in direction Z overlaps with the projection of cavity 118 in direction Z, and the projection of opening 143 in direction Z overlaps with each other. The material of adhesive layer 151 may be similar to or the same as the material of adhesive layer 142, and the material of adhesive layer 151 may include glass fiber and epoxy resin.

[0039] Multiple heat sinks 161 and 162 are disposed on the heat-conducting portion 141a of the circuit layer 141 of the circuit board 140. The circuit board 140 is located between the multiple heat sinks 161 and 162 and multiple electronic components 121 and 122, wherein the circuit layer 141 is located between the heat sinks 161 and 162 and the adhesive layer 142. The circuit board 140 has a more rigid structure than the flexible circuit board 110 and can be used to support the heat sinks 161 and 162. Further, the vertical projections of the heat sinks 161 and 162 on the flexible circuit board 110 are equal to or greater than the vertical projections of the electronic components 121 and 122 on the flexible circuit board 110. That is, the projections of the heat sinks 161 and 162 in the Z direction at least completely overlap or protrude from the projections of the electronic components 121 and 122 in the Z direction. In addition, the projections of the heat sinks 161 and 162 in the Z direction do not overlap with the projections of the cavity 118 and the openings 143 and 152 in the Z direction.

[0040] exist Figure 1 In the example, the vertical projections of heat sinks 161 and 162 onto the flexible circuit board 110 are equal to the vertical projections of electronic components 121 and 122 onto the flexible circuit board 110, respectively. The materials of heat sinks 161 and 162 can be steel sheets or graphite composite thermal conductive films combining graphite and adhesive layers, without limitation.

[0041] Multiple heat-conducting structures 170 are disposed within the circuit board 140. The multiple heat-conducting structures 170 may be columnar in shape. Each heat-conducting structure 170 extends from the heat sink 161 or 162 through the circuit layer 141, the adhesive layer 142, and to the electronic component 121 or 122, connecting the heat sink 161 or 162, the heat-conducting portion 141a of the circuit layer 141, the adhesive layer 142, and the electronic component 121 or 122. The heat-conducting structures 170 are used to conduct the heat generated by the electronic components 121 and 122 to the circuit layer 141 and the heat sinks 161 and 162. Because the surfaces of the heat sinks 161 and 162 are connected to the circuit layer 141 and the heat-conducting structures 170, the heat dissipation area is increased to improve the heat dissipation effect.

[0042] The material of the thermally conductive structure 170 can be similar to or the same as that of the conductive structure 130. The material of the thermally conductive structure 170 can include epoxy resin and metal. The metal is distributed within the epoxy resin. The metal can include silver and / or copper. The epoxy resin can bond the heat sinks 161, 162, the thermally conductive part 141a, the adhesive layer 142, and the electronic components 121, 122, while the metal can conduct the heat energy of the electronic components 121, 122 to the thermally conductive part 141a and the heat sinks 161, 162. It should be noted that the thermally conductive part 141a of the circuit layer 141 is separated from the traces 141b of the circuit layer 141. Therefore, even if the thermally conductive structure 170 is electrically connected to the thermally conductive part 141a and the heat sinks 161, 162, it will not affect the signal transmission of the traces 141b of the circuit layer 141.

[0043] Two solder resist layers 181 and 182 cover circuit boards 150 and 140 respectively, with flexible circuit boards 110, 140, and 150 located between the two solder resist layers 181 and 182. Solder resist layer 181 does not cover opening 152 and exposes a portion of the flexible circuit board 110. Solder resist layer 182 does not cover opening 143 and exposes a portion of the flexible circuit board 110 and multiple heat sinks 161 and 162. The surface of solder resist layer 182 is flush with the surfaces of heat sinks 161 and 162.

[0044] As can be seen from the above structure, electronic components 121 and 122 are embedded within flexible circuit boards 110, 140, and 150, and are directly electrically connected to the transmission section 111a of the circuit layer 111 via conductive structure 130. This shortens the transmission path of electronic components 121 and 122, reduces transmission loss, and improves transmission quality. Furthermore, conductive structure 130 only passes through and electrically connects to the circuit layer 111, without passing through other circuit layers, thus ensuring the shortest transmission path between electronic components 121 and 122.

[0045] Secondly, the cavity 118 covered by the transmission section 111a is designed as an air gap, so that the dielectric material corresponding to the transmission section 111a is air. Therefore, the electronic components 121 and 122 transmit signals through the transmission section 111a, which not only increases the flexibility between the electronic components 121 and 122 and reduces the thickness of the circuit board assembly 100, but also makes the transmission section 111a suitable for transmitting high-frequency and high-speed signals. Furthermore, the heat generated by the electronic components 121 and 122 is conducted through the heat-conducting structure 170 to the heat-conducting section 141a and the heat sinks 161 and 162 of the circuit layer 141, thereby increasing the heat dissipation area and improving the heat dissipation effect.

[0046] Figures 2A to 2D yes Figure 1 A partial cross-sectional view of the step of providing a flexible circuit board 110 in the manufacturing method of circuit board assembly 100, wherein... Figure 2A This is a partial cross-sectional schematic diagram of the flexible substrate 200. Figure 2B This is a partial cross-sectional schematic diagram showing the formation of multiple grooves 230, 240, and 250. Figure 2C This is a partial cross-sectional schematic diagram combining flexible substrates 200 and 300, and Figure 2D This is a partial cross-sectional schematic diagram of the flexible circuit board 110. (See attached diagram.) Figure 2A A flexible substrate 200 is provided, wherein the flexible substrate 200 includes metal layers 210 and 220 and a dielectric layer 114. The metal layers 210 and 220 and the dielectric layer 114 are stacked, and the dielectric layer 114 is sandwiched between the metal layers 210 and 220. The metal layers 210 and 220 may be copper layers.

[0047] See Figure 2B Multiple grooves 230, 240, and 250 are formed. Groove 230 penetrates the metal layer 220 and the dielectric layer 114, exposing the metal layer 210. Grooves 240 and 250 penetrate the metal layer 220, exposing the dielectric layer 114. Groove 230 is located between grooves 240 and 250. The formation of multiple grooves 230, 240, and 250 can be accomplished by laser cutting.

[0048] See Figure 2B and Figure 2CFirst, a flexible substrate 300 is provided, wherein the flexible substrate 300 includes a metal layer 310 and a dielectric layer 115. The metal layer 310 and the dielectric layer 115 are stacked. The metal layer 310 may be a copper layer. Next, a metal layer 220 is patterned such that the metal layer 220 forms a circuit layer 112. The patterned metal layer 220 may be completed by photolithography and etching processes. Next, flexible substrates 200 and 300 are combined. The flexible substrate 300 covers recesses 230, 240, and 250. The dielectric layer 115 of the flexible substrate 300 faces the recesses 230, 240, and 250 to contact the circuit layer 112 and the dielectric layer 114. The dielectric layer 115 covers the recess 230 such that the recess 230 forms a closed cavity 118. Figure 2D The dielectric layer 115 fills the grooves 240 and 250. The flexible substrates 200 and 300 can be bonded together by thermoforming.

[0049] See Figure 2C and Figure 2D The metal layers 210 and 310 are patterned so that they form circuit layers 111 and 113, respectively, wherein the transmission portion 111a of the circuit layer 111 covers the cavity 118. The patterned metal layers 210 and 310 can be fabricated using photolithography and etching processes. Next, capping layers 116 and 117 are formed on the circuit layers 111 and 113, respectively, to form a flexible circuit board 110. The capping layers 116 and 117 can be bonded to the circuit layers 111 and 113 using a thermo-press bonding method.

[0050] Figure 3 yes Figure 1 A partial cross-sectional view of the method for manufacturing the circuit board assembly 100, showing the arrangement of multiple electronic components 121 and 122. (See attached diagram.) Figure 3 Multiple recesses 410 and 420 are formed in the flexible circuit board 110. A cavity 118 is located between these recesses 410 and 420. Each recess 410 or 420 extends from the cover layer 117 to the circuit layer 113, the dielectric layer 115, and then to the circuit layer 112 to expose the dielectric layer 114. In other words, each recess 410 or 420 does not penetrate the dielectric layer 114. The recesses 410 and 420 can be formed using laser cutting. Next, electronic components 121 and 122 are respectively disposed in the multiple recesses 410 and 420. The electronic components 121 and 122 are exposed from the flexible circuit board 110, and the cavity 118 is located between the electronic components 121 and 122.

[0051] Figure 4 yes Figure 1 A partial cross-sectional view of the conductive structure 130 in the manufacturing method of the circuit board assembly 100. (See attached diagram.) Figure 4A plurality of through-holes 430 are formed in the flexible circuit board 110. Each through-hole 430 extends from the cover layer 116 to the circuit layer 111 and then to the dielectric layer 114 to expose a portion of the electronic component 121 or 122. The plurality of through-holes 430 can be formed using laser drilling. Next, a conductive material is disposed within these through-holes 430 such that the conductive material contacts the electronic components 121 and 122 and the sides of the circuit layer 111. Then, the flexible circuit board 110 is heated so that the conductive material within these through-holes 430 respectively forms a plurality of conductive structures 130.

[0052] Figure 5 yes Figure 1 A partial cross-sectional view of the bonding substrates 500 and 600 and the flexible circuit board 110 in the manufacturing method of the circuit board assembly 100. (See attached diagram.) Figure 5 Substrates 500 and 600 are provided. Substrate 500 includes a metal layer 510 and an adhesive layer 142. The metal layer 510 and the adhesive layer 142 are stacked. The metal layer 510 may be a copper layer. Substrate 600 includes a metal layer 610 and an adhesive layer 151. The metal layer 610 and the adhesive layer 151 are stacked. The metal layer 610 may be a copper layer. Next, two recesses 520 are formed on substrate 500. Each recess 520 penetrates the adhesive layer 142 and exposes the metal layer 510. Two recesses 620 are formed on substrate 600. Each recess 620 penetrates the adhesive layer 151 and exposes the metal layer 610.

[0053] Next, substrates 500 and 600 are joined with flexible circuit board 110, which is located between substrates 500 and 600. The adhesive layer 142 of substrate 500 faces the cover layer 117 of flexible circuit board 110 and the exposed electronic components 121 and 122, covering the electronic components 121 and 122. The adhesive layer 151 of substrate 600 faces the cover layer 116 of flexible circuit board 110. Specifically, two grooves 520 are aligned with the two ends of cavity 118, and two grooves 620 are also aligned with the two ends of cavity 118. In other words, the vertical projections of the plurality of grooves 520 and 620 on flexible circuit board 110 overlap with each other and also partially overlap with the vertical projections of cavity 118 on flexible circuit board 110. Substrates 500 and 600 and flexible circuit board 110 can be joined using a thermoforming method.

[0054] Figure 6 yes Figure 1 A partial cross-sectional view of the process of forming multiple through holes 710 and removing the metal layer 610 in the manufacturing method of the circuit board assembly 100. (See attached diagram.) Figure 5 and Figure 6A plurality of through holes 710 are formed on the substrate 500. Each through hole 710 extends from the metal layer 510 to the adhesive layer 142 to expose a local electronic component 121 or 122. The plurality of through holes 710 can be formed using laser drilling. Next, the metal layer 610 is removed to expose the adhesive layer 151, thereby forming a circuit board 150 on the substrate 600. The metal layer 610 can be removed using laser ablation.

[0055] Figure 7 yes Figure 1 A partial cross-sectional view of the method for manufacturing the circuit board assembly 100, including forming openings 143 and 152, setting a heat-conducting structure 170, and forming a circuit layer 141. (See attached diagram.) Figure 6 and Figure 7 Next, a portion of the metal layer 510 and a portion of the adhesive layer 142 between the two recesses 520 are removed, forming an opening 143 in the substrate 500, wherein the opening 143 exposes a portion of the cover layer 117. Then, a portion of the adhesive layer 151 between the two recesses 620 is removed, forming an opening 152 in the circuit board 150, wherein the opening 152 exposes a portion of the cover layer 116. The portion of the metal layer 510 and the portion of the adhesive layer 142 between the two recesses 520, and the portion of the adhesive layer 151 between the two recesses 620, can be removed manually or mechanically.

[0056] Next, a thermally conductive material is placed within these through-holes 710, making the thermally conductive material contact the electronic components 121 and 122. Then, the substrate 500 is heated, causing the thermally conductive material within these through-holes 710 to form multiple thermally conductive structures 170. Next, a patterned metal layer 510 is formed to create a circuit layer 141, thereby forming a circuit board 140 on the substrate 500. The patterned metal layer 510 can be formed using photolithography and etching processes. Next, in the Z-direction projection, the circuit layer 141 forms at least two recesses 810 at positions corresponding to the positions surrounding the electronic components 121 and 122, separating the circuit layer 141 outside the recesses 810 from the thermally conductive structures 170. The recesses 810 can be formed using laser cutting.

[0057] Figure 8 yes Figure 1 A partial cross-sectional view of the solder resist layers 181 and 182 in the manufacturing method of the circuit board assembly 100. (See attached diagram.) Figure 7 and Figure 8Solder resist layers 182 and 181 are respectively provided on the circuit layer 141 of circuit board 140 and the adhesive layer 151 of circuit board 150. Solder resist layers 182 and 181 can be printed onto the circuit layer 141 and adhesive layer 151, respectively. Solder resist layers 182 and 181 cover circuit board 140 and circuit board 150, respectively, and expose portions of flexible circuit board 110. For example, solder resist layer 182 covers groove 810 but does not cover opening 143, and exposes portions of cover layer 117. Solder resist layer 181 does not cover opening 152, and exposes portions of cover layer 116.

[0058] Figure 9 yes Figure 1 A partial cross-sectional view of the groove 910 formed in the manufacturing method of the circuit board assembly 100. (See attached diagram.) Figure 9 Multiple grooves 910 are formed on the solder resist layer 182 to expose portions of the circuit layer 141 and multiple heat-conducting structures 170, wherein the exposed portions of the circuit layer 141 by the multiple grooves 910 are heat-conducting portions 141a. Specifically, these grooves 910 overlap at least with electronic components 121 and 122 in the Z direction, respectively. Next, heat sinks 161 and 162 are provided in these grooves 910, such that the heat sinks 161 and 162 contact the exposed heat-conducting portions 141a and multiple heat-conducting structures 170 of the grooves 910, as shown below. Figure 1 As shown. Thus, the manufacturing of the circuit board assembly 100 is essentially complete.

[0059] In summary, in the circuit board assembly 100 disclosed in the above embodiments, electronic components 121 and 122 are embedded within flexible circuit boards 110, 140, and 150, and are directly electrically connected to the transmission section 111a of the circuit layer 111 via conductive structure 130. This shortens the transmission path of electronic components 121 and 122, reduces transmission loss, and improves transmission quality. Secondly, signals are transmitted between electronic components 121 and 122 via the transmission section 111a covering the cavity 118, which not only increases the flexibility between electronic components 121 and 122 and reduces the thickness of the circuit board assembly 100, but also makes the transmission section 111a suitable for transmitting high-frequency and high-speed signals. Furthermore, the heat generated by electronic components 121 and 122 is conducted to the heat-conducting section 141a and heat sinks 161 and 162 of the circuit layer 141 via heat-conducting structure 170, thereby increasing the heat dissipation area and improving heat dissipation effect.

[0060] Although this application has been disclosed above with reference to embodiments, it is not intended to limit this application. Those skilled in the art can make some modifications and refinements without departing from the spirit and scope of this application. Therefore, the scope of protection of this application shall be determined by the appended claims.

[0061] [Symbol Explanation]

[0062] 100: Circuit board assembly

[0063] 110: Flexible Circuit Board

[0064] 111~113,141: Line layer

[0065] 111a: Transmission Section

[0066] 114, 115: Dielectric layer

[0067] 116, 117: Overlay

[0068] 118: Cavity

[0069] 121, 122: Electronic components

[0070] 130: Conductive structure

[0071] 140, 150: Circuit board

[0072] 141a: Thermal conductive part

[0073] 141b: Wiring

[0074] 142, 151: Adhesive layer

[0075] 143,152: Opening

[0076] 161, 162: Heat sink

[0077] 170: Thermally conductive structure

[0078] 181, 182: Solder resist layer

[0079] 200, 300: Flexible substrate

[0080] 210, 220, 310, 510, 610: Metal layer

[0081] 230, 240, 250, 410, 420, 520, 620, 810, 910: Groove

[0082] 500,600:Substrate

[0083] 430,710: Perforation

[0084] X, Y, Z: Direction.

Claims

1. A circuit board assembly, characterized in that, Include: A flexible circuit board includes a first circuit layer and a first dielectric layer, wherein the first dielectric layer has a cavity, the first circuit layer has a transmission section, and the transmission section covers the cavity. Multiple electronic components are disposed within the flexible circuit board and electrically connected to the first circuit layer, wherein the cavity is located between the multiple electronic components, and the multiple electronic components are electrically connected to each other via the transmission section; A first circuit board, stacked with the flexible circuit board, includes a second circuit layer and has a first opening, wherein the first opening exposes a portion of the flexible circuit board, and the vertical projection of the first opening on the flexible circuit board overlaps with the vertical projection of the cavity on the flexible circuit board. The plurality of electronic components are located between the second circuit layer and the flexible circuit board. The second circuit layer has a heat-conducting portion and at least one trace, the heat-conducting portion and the at least one trace being separated. as well as Multiple heat sinks are disposed on the heat-conducting portion of the second circuit layer and are respectively superimposed on the multiple electronic components, wherein the first circuit board is located between the multiple heat sinks and the multiple electronic components.

2. The circuit board assembly according to claim 1, characterized in that, Also includes: Multiple conductive structures are disposed within the flexible circuit board, wherein each of the multiple conductive structures extends from the first circuit layer through the first dielectric layer and to one of the multiple electronic components, so as to electrically connect the first circuit layer and one of the multiple electronic components.

3. The circuit board assembly according to claim 2, characterized in that, The materials of the plurality of conductive structures include epoxy resin and metal, wherein the metal is distributed within the epoxy resin.

4. The circuit board assembly according to claim 1, characterized in that, Also includes: Multiple heat-conducting structures are disposed within the first circuit board, wherein each of the multiple heat-conducting structures extends from one of the multiple heat sinks through the second circuit layer and to one of the multiple electronic components, so as to connect one of the multiple heat sinks, the second circuit layer and one of the multiple electronic components.

5. The circuit board assembly according to claim 4, characterized in that, The materials of the plurality of thermally conductive structures include epoxy resin and metal, wherein the metal is distributed within the epoxy resin.

6. The circuit board assembly according to claim 1, characterized in that, Also includes: A second circuit board, stacked with the flexible circuit board, has a second opening, wherein the second opening exposes a portion of the flexible circuit board, and the vertical projection of the second opening on the flexible circuit board overlaps with the vertical projection of the cavity on the flexible circuit board, the flexible circuit board being located between the first circuit board and the second circuit board.

7. The circuit board assembly according to claim 6, characterized in that, Also includes: Multiple solder resist layers cover the first circuit board and the second circuit board respectively, and expose portions of the flexible circuit board and the plurality of heat sinks.

8. A method for manufacturing a circuit board assembly, characterized in that, Include: A flexible circuit board is provided, wherein the flexible circuit board has a cavity; Multiple electronic components are disposed within the flexible circuit board, wherein the flexible circuit board exposes the multiple electronic components, and the cavity is located between the multiple electronic components; Provide substrate; After the plurality of electronic components are disposed within the flexible circuit board, the substrate and the flexible circuit board are combined, wherein the substrate covers the plurality of electronic components. After combining the substrate and the flexible circuit board, an opening is formed in the substrate, wherein the opening exposes a portion of the flexible circuit board, and the vertical projection of the opening on the flexible circuit board overlaps with the vertical projection of the cavity on the flexible circuit board. After the opening is formed, the metal layer of the substrate is patterned to form a circuit board; as well as Multiple heat sinks are disposed on the circuit board, wherein the circuit board is located between the multiple heat sinks and the multiple electronic components.

9. The manufacturing method according to claim 8, characterized in that, The flexible circuit board includes: A first flexible substrate is provided, wherein the first flexible substrate includes a first metal layer and a first dielectric layer; A groove is formed in the first dielectric layer, wherein the groove exposes the first metal layer; Provide a second flexible substrate; After the groove is formed, the first flexible substrate and the second flexible substrate are combined, wherein the second flexible substrate covers the groove, so that the groove forms the cavity; as well as After the cavity is formed, the first metal layer is patterned to form a first circuit layer, such that the first flexible substrate and the second flexible substrate form the flexible circuit board.

10. The manufacturing method according to claim 8, characterized in that, Also includes: After combining the substrate and the flexible circuit board, a plurality of through holes are formed in the substrate, wherein the plurality of through holes expose portions of the plurality of electronic components; Thermally conductive material is disposed in the plurality of perforations such that the thermally conductive material contacts the plurality of electronic components; as well as After the thermally conductive material is applied, it is heated to form multiple thermally conductive structures.

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