Circuit board and method for manufacturing the same

Abstract

The present invention proposes a method for manufacturing a circuit board, comprising: providing a first main body, the first main body comprising a first stacking structure and a first conductive layer and a second conductive layer arranged on opposite surfaces of the first stacking structure; opening a blind hole on the first main body, the blind hole penetrating the first stacking structure and the first conductive layer; setting a third conductive layer on the inner wall of the blind hole to form a conductive hole; etching the first conductive layer to obtain a first conductive circuit, etching the second conductive layer to obtain a second conductive circuit; filling solder paste in the conductive hole; removing part of the second conductive circuit and the third conductive layer to form a conductive through hole penetrating the first main body, exposing a part of the solder paste close to the second conductive circuit; providing a second main body, the second main body comprising a plurality of welding gaps, stacking the first main body and the second main body, and connecting the conductive through hole with the welding gap; heating the solder paste by light, and melting the solder paste and flowing into the welding gap to solidify to achieve welding of the first main body and the second main body. The present invention also provides a circuit board.

Description

Technical Field

[0001] The present invention relates to the field of electronic products, and in particular to a circuit board and a manufacturing method thereof. Background Art

[0002] In recent years, electronic products have been widely used in daily work and life. Light, thin and small electronic products are becoming more and more popular. Circuit boards are the key parts of electronic products, and there are many demands for their functionality. Multifunctional circuit boards often need to use welding processes to connect different sub-boards. Low-temperature welding and selective welding are more common welding technologies. Light-curing welding can ensure local welding and low-temperature welding of products due to its advantages of short time and shielding.

[0003] Existing light-curing welding often heats the blind hole to melt the solder paste buried in the blind hole and then achieve welding. However, when this welding method heats the solder paste, some structures in the circuit board (such as the solder mask layer and the conductive circuit) are heated at the same time. Due to the different materials, thermal conductivity and thermal expansion coefficients of the multi-layer structure of the circuit board, there is a possibility of circuit board explosion. The traditional heating method does not directly heat the solder paste, so the heating time of the entire circuit board is relatively long, further increasing the risk of explosion.

[0004] How to solve the above problems is what those skilled in the art need to consider. Summary of the invention

[0005] In view of the above situation, it is necessary to provide a method for manufacturing a circuit board and a circuit board manufactured by the method for manufacturing a circuit board.

[0006] The present application provides a method for manufacturing a circuit board, comprising:

[0007] Providing a first body, the first body comprising a first stacking structure and a first conductive layer and a second conductive layer disposed on two opposite surfaces of the first stacking structure;

[0008] A plurality of blind holes are provided at intervals on the first body, wherein the blind holes penetrate the first stacked structure and the first conductive layer, and the blind holes do not penetrate or partially penetrate the second conductive layer;

[0009] Disposing a third conductive layer on the inner wall of the blind hole to form a conductive hole;

[0010] Etching the first conductive layer to obtain a first conductive circuit, and etching the second conductive layer to obtain a second conductive circuit;

[0011] Filling solder paste in the conductive hole;

[0012] Removing a portion of the second conductive circuit and the third conductive layer to form a conductive through hole penetrating the first body, so that at least a portion of the solder paste near the second conductive circuit is exposed;

[0013] Providing a second body, wherein a welding gap is provided between the first body and the second body, so that the first body and the second body are stacked and arranged, and the conductive through hole is connected to the welding gap; and

[0014] The solder paste is heated by light, and after being melted, the solder paste flows into the welding gap and solidifies to achieve welding of the first body and the second body.

[0015] In a possible implementation, the conductive via includes a first end and a second end, the first end is arranged on a side of the conductive via close to the first conductive circuit, and the second end is arranged on a side of the conductive via close to the second conductive circuit; the second end is connected to the welding gap.

[0016] In a possible embodiment, the solder paste is filled in the conductive through hole and overflows from the first end in a direction away from the first stacking structure; after the first body and the second body are stacked, a heating light is used to irradiate the solder paste on the side close to the first end; the solder paste partially melts and flows into the welding gap through the second end; and the melted solder paste is solidified.

[0017] In a possible embodiment, the conductive via includes a first end and a second end, the first end is arranged on a side of the conductive via close to the first conductive circuit, and the second end is arranged on a side of the conductive via close to the second conductive circuit; after forming the conductive via, solder paste is added to the second end; and the second body is provided so that the first end is connected to the welding gap.

[0018] In a possible implementation manner, the opening aperture of the first end is larger than the opening aperture of the second end; the solder paste is filled in the conductive through hole and overflows from the first end in a direction away from the first stacking structure; when adding solder paste to the second end, the added solder paste overflows from the second end in a direction away from the first stacking structure; after the first body and the second body are stacked, a heating light is used to irradiate the solder paste on a side close to the second end;

[0019] The solder paste partially melts and flows into the welding gap through the first end portion; and the melted solder paste is solidified.

[0020] In a possible implementation manner, one welding gap is connected to at least two of the first end portions.

[0021] The present application also provides a circuit board, comprising:

[0022] A first body, the first body comprising a first stacking structure and a first conductive circuit and a second conductive circuit disposed on two opposite surfaces of the first stacking structure;

[0023] a second body, the second body being stacked with the first body, and a welding gap being sandwiched between the first body and the second body;

[0024] A conductive through hole, the conductive through hole passes through the first body and is connected to the welding gap, a plurality of the conductive through holes are arranged at intervals on the first body, the conductive through hole comprises a conductive hole and a first window, the conductive hole passes through the first conductive line, the first window passes through the second conductive line, and the conductive hole is connected to the first window; and

[0025] Solder paste is filled in the conductive through hole and the welding gap to weld the first body and the second body.

[0026] In a possible embodiment, the conductive via includes a first end and a second end, the first end is arranged on a side of the conductive via close to the first conductive circuit, and the second end is arranged on a side of the conductive via close to the second conductive circuit, the solder paste is filled in the conductive via and overflows from the first end in a direction away from the first stacking structure, and the second end is connected to the welding gap.

[0027] In a possible embodiment, the conductive via includes a first end and a second end, the first end is arranged on a side of the conductive via close to the first conductive circuit, and the second end is arranged on a side of the conductive via close to the second conductive circuit, the solder paste is filled in the conductive via and overflows from the first end and the second end respectively in a direction away from the first stacking structure, and the first end is connected to the welding gap.

[0028] In a possible implementation manner, the opening aperture of the first end is larger than the opening aperture of the second end, and a first solder resist layer is disposed on a portion of the surface of the first conductive circuit and the second conductive circuit away from the first stacking structure.

[0029] The circuit board and the manufacturing method thereof provided in the embodiments of the present invention can be manufactured by printing solder paste, without adding other equipment such as a ball planting machine, thereby reducing costs; the solder paste is directly exposed to light and directly heated, without relying on conductive blind holes or the circuit board body for heat transfer, which can effectively reduce the risk of board explosion; the solder paste is in direct contact with the conductive through-hole, and the hole wall of the conductive through-hole is added to the welding contact surface, thereby improving the welding tensile strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figures 1 to 7 It is a schematic diagram of the manufacturing process of the circuit board according to the first embodiment of the present invention.

[0031] Figure 8 It is a schematic structural diagram of a circuit board according to the first embodiment of the present invention.

[0032] Figures 9 to 16 It is a schematic diagram of the manufacturing process of the circuit board according to the second embodiment of the present invention.

[0033] Fig.17 Schematic diagram of the structure of a circuit board according to the second embodiment of the present invention.

[0034] Main component symbols

[0035] Circuit board 1, 2

[0036] First body 11, 21

[0037] The first stacked structure 110 , 210

[0038] First conductive layers 111, 211

[0039] Second conductive layers 112, 212

[0040] The third conductive layer 113, 213

[0041] First conductive circuits 115, 215

[0042] Second conductive paths 116 , 216

[0043] First solder resist layers 117 and 217

[0044] Second body 12, 22

[0045] The second stacking structure 120 , 220

[0046] Solder pads 121, 221

[0047] Fifth conductive circuit 125, 225

[0048] Sixth conductive circuit 126, 226

[0049] Second solder resist layers 127 and 227

[0050] Welding gap 129, 229

[0051] Blind hole 131, 231

[0052] Conductive holes 132, 232

[0053] Conductive vias 133, 233

[0054] First end 134, 234

[0055] Second end 135, 235

[0056] First window 136, 236

[0057] Solder paste 15, 25

[0058] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centrally disposed element at the same time. When an element is considered to be "disposed on" another element, it may be directly disposed on the other element or there may be a centrally disposed element at the same time.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0062] First embodiment

[0063] like Figures 1 to 7 As shown, a method for manufacturing a circuit board 1 provided in the first embodiment of the present application includes the following steps:

[0064] Step S11: Figure 1 As shown, a first body 11 is provided. The first body 11 includes a first stacking structure 110 and a first conductive layer 111 and a second conductive layer 112 disposed on two opposite surfaces of the first stacking structure 110 .

[0065] In one embodiment, the first stacked structure 110 may be a multilayer board, and the first stacked structure 110 may include at least two layers of substrates, the substrate material may be a resin such as polyimide (PI), and an adhesive layer disposed between the two layers of substrates for connection. In other embodiments, the first stacked structure 110 may be other multilayer circuit structures, for example, a multilayer circuit board including embedded components.

[0066] In one embodiment, the first conductive layer 111 and the second conductive layer 112 are conductive materials, such as copper, and the first conductive layer 111 and the second conductive layer 112 may be formed by an additive method, a subtractive method, or the like.

[0067] Step S12: Figure 1 As shown, a plurality of blind holes 131 are disposed at intervals on the first body 11 , and the blind holes 131 penetrate the first stacking structure 110 and the first conductive layer 111 .

[0068] In one embodiment, the blind hole 131 may be formed by laser drilling. During the laser drilling process, the second conductive layer 112 is not penetrated by the laser.

[0069] In one embodiment, the second conductive circuit layer 112 may be partially broken down.

[0070] Step S13: Figure 2 As shown, a third conductive layer 113 is disposed on the inner wall of the blind hole 131 to form a conductive hole 132 .

[0071] In one embodiment, the third conductive layer 113 at least covers the inner wall of the blind hole 131 , and extends to at least a portion of the surface of the first conductive layer 111 away from the first stacked structure 110 .

[0072] Step S14, as Figure 3 As shown, the first conductive layer 111 is etched to obtain the first conductive line 115 , and the second conductive layer 112 is etched to obtain the second conductive line 116 .

[0073] In one embodiment, the first conductive layer 111 and the second conductive layer 112 may be patterned by a pattern transfer process.

[0074] In one embodiment, the third conductive layer 113 may be surface treated, and a microstructure 114 may be formed on the inner wall of the third conductive layer 113 .

[0075] In one embodiment, a first solder resist layer 117 is formed on the surface of the first conductive circuit 115 and the second conductive circuit 116 away from the first stacked structure 110, and the first solder resist layer 117 can cover the exposed surfaces of the first conductive circuit 115 and the second conductive circuit 116; the conductive through hole 133 is not covered by the first solder resist layer 117, and at least a portion of the second conductive circuit 116 corresponding to the conductive through hole 133 is not covered by the first solder resist layer 117.

[0076] Step S15, as Figure 4 As shown, the conductive hole 132 is filled with solder paste 15 .

[0077] In one embodiment, the solder paste 15 may be disposed by printing so that the solder paste 15 fills the conductive via 132 and overflows from the opening of the conductive via 132 to cover the surface of the conductive via 132 away from the first stacked structure 110 .

[0078] Step S16, as Figure 5 As shown, the second conductive circuit 116 and a portion of the third conductive layer 113 are removed to form a conductive through hole 133 penetrating the first body 11 , so that at least a portion of the solder paste 15 near the second conductive circuit 116 is exposed.

[0079] In one embodiment, a portion of the second conductive circuit 116 and the third conductive layer 113 is removed to form a first window 136 , and the first window 136 is connected to the conductive hole 132 to form a conductive through hole 133 .

[0080] In one embodiment, the portion of the second conductive circuit 116 not covered by the first solder resist layer 117 is removed to expose the bottom of the conductive hole 132, and the third conductive layer 113 at the bottom of the conductive hole 132 is further removed to expose the solder paste in the conductive hole 132. The conductive structure of the conductive hole 132 is changed from a blind hole to a through hole to obtain a conductive through hole 133.

[0081] In one embodiment, the second conductive circuit 116 and a portion of the third conductive layer 113 may be removed by laser cutting.

[0082] In one embodiment, the conductive via 133 includes a first end 134 and a second end 135. The first end 134 is disposed on a side of the conductive via 133 close to the first conductive line 115, and the second end 135 is disposed on a side of the conductive via 133 close to the second conductive line 116. In this embodiment, the cross-sectional area of ​​the first end 134 is greater than the cross-sectional area of ​​the second end 135.

[0083] Step S17, Figure 6As shown, a second body 12 is provided, and the first body 11 and the second body 12 are stacked and arranged. A welding gap 129 is provided between the first body 11 and the second body 12, and the conductive through hole 133 is connected to the welding gap 129.

[0084] In one embodiment, the second body 12 may include a second stacking structure 120 , and a plurality of welding pads 121 are disposed on at least one side surface of the second stacking structure 120 . The plurality of welding pads 121 are disposed in the welding gap 129 .

[0085] In one embodiment, the second end portion 135 is connected to the welding gap 129 . Specifically, the second end portion 135 is directly opposite to the welding gap 129 and is connected to the space in the welding gap 129 to facilitate the flow of the solder paste 15 during the subsequent heating process.

[0086] In one embodiment, the second stacked structure 120 may be a multi-layer board, and the second stacked structure 120 may include at least one layer of substrate (e.g., PI), and a fifth conductive circuit 125 and a sixth conductive circuit 126 disposed on two opposite surfaces of the layer of substrate, and a second solder resist layer 127 may be disposed on the surfaces of the fifth conductive circuit 125 and the sixth conductive circuit 126, and a plurality of welding gaps 129 may be separated by the second solder resist layer 127. In other embodiments, the second stacked structure 120 may be other multi-layer structures, for example, a multi-layer circuit board including inner conductive circuits or embedded components.

[0087] Step S18, Figure 7 As shown, the solder paste 15 is heated by light, and after melting, the solder paste 15 flows into the welding gap 129 and solidifies to achieve welding of the first body 11 and the second body 12 .

[0088] In one embodiment, the solder paste 15 is filled in the conductive through hole 133 and overflows from the first end 134 in a direction away from the first stacking structure 110; a heating light is used to irradiate the solder paste 15 on the side close to the first end 134, and the solder paste 15 overflowing the first end 134 is directly irradiated with the light and heated to melt. The melted solder paste 15 flows into the welding gap 129 through the second end 135 under the action of gravity and contacts the solder pad 121.

[0089] The melted solder paste 15 is solidified to achieve welding between the first body 11 and the second body 12 .

[0090] like Figure 8 As shown, a circuit board 1 is provided in the first embodiment of the present invention. The circuit board 1 includes a first body 11 , a second body 12 and solder paste 15 . The first body 11 and the second body 12 are stacked and soldered by the solder paste 15 .

[0091] The first body 11 includes a first stacking structure 110 and a first conductive circuit 115 and a second conductive circuit 116 disposed on two opposite surfaces of the first stacking structure 110. In one embodiment, the first stacking structure 110 may be a multilayer board, and the first stacking structure 110 may include at least two layers of substrate (e.g., PI), and an adhesive layer disposed between the two layers of substrate for connection. In other embodiments, the first stacking structure 110 may be other multilayer circuit structures. The first conductive circuit 115 and the second conductive circuit 116 are conductive materials, such as copper. In one embodiment, the first body 11 also includes a first solder resist layer 117, and the first solder resist layer 117 may cover the exposed surfaces of the first conductive circuit 115 and the second conductive circuit 116.

[0092] The first main body 11 is provided with a plurality of conductive through holes 133 arranged at intervals. The conductive through holes 133 penetrate the first main body 11. The conductive through holes 133 penetrate the first stacked structure 110, the first conductive circuit 115 and the second conductive circuit 116. The inner wall of the conductive through hole 133 is provided with a third conductive layer 113. The third conductive layer 113 is electrically connected to the first conductive circuit 115 and the second conductive circuit 116. The third conductive layer 113 covers the surface of the first conductive circuit 115 near the periphery of the conductive through hole 133.

[0093] In one embodiment, the conductive via 133 includes a conductive hole 132 and a first window 136 . The conductive hole 132 penetrates the first conductive circuit 115 . The first window 116 penetrates the second conductive circuit 116 . The conductive hole 132 is connected to the first window 136 .

[0094] In one embodiment, the conductive via 133 is not covered by the first solder resist layer 117 , and at least a portion of the second conductive trace 116 corresponding to the conductive via 133 is not covered by the first solder resist layer 117 .

[0095] The conductive via 133 includes a first end 134 and a second end 135. The first end 134 is disposed on a side of the conductive via 133 close to the first conductive line 115, and the second end 135 is disposed on a side of the conductive via 133 close to the second conductive line 116. The solder paste 15 is filled in the conductive via 133 and overflows from the first end 134 in a direction away from the first stacking structure 110. The second end 135 is connected to the welding gap 129. In this embodiment, the cross-sectional area of ​​the first end 134 is greater than the cross-sectional area of ​​the second end 135.

[0096] The first body 11 and the second body 12 are stacked, a welding gap 129 is sandwiched between the first body 11 and the second body 12, and the conductive through hole 133 is connected to the welding gap 129. In one embodiment, the second body 12 may include a second stacked structure 120, and a plurality of solder pads 121 are disposed on at least one side surface of the second stacked structure 120, and the plurality of solder pads 121 are disposed in the welding gap 129. The second stacked structure 120 may be a multi-layer board, and the second stacked structure 120 may include at least one layer of substrate (such as PI), and a fifth conductive circuit 125 and a sixth conductive circuit 126 disposed on two opposite surfaces of the layer of substrate, and a second solder resist layer 127 may be disposed on the surface of the fifth conductive circuit 125 and the sixth conductive circuit 126, and a plurality of welding gaps 129 may be separated by the second solder resist layer 127. In other embodiments, the second stacked structure 120 may be other multi-layer structures, for example, a multi-layer circuit board including embedded components.

[0097] Second embodiment

[0098] like Figures 9 to 16 As shown, a method for manufacturing a circuit board 2 provided in the second embodiment of the present application includes the following steps:

[0099] Step S21: Fig. 9 As shown, a first body 21 is provided. The first body 21 includes a first stacking structure 210 and a first conductive layer 211 and a second conductive layer 212 disposed on two opposite surfaces of the first stacking structure 210 .

[0100] In one embodiment, the first stacked structure 210 may be a multi-layer board, and the first stacked structure 210 may include at least two layers of substrates, the substrate material may be a resin such as polyimide (PI), and an adhesive layer disposed between the two layers of substrates for connection. In other embodiments, the first stacked structure 210 may be other multi-layer circuit structures, for example, a multi-layer circuit board including embedded components.

[0101] In one embodiment, the first conductive layer 211 and the second conductive layer 212 are conductive materials, such as copper, and the first conductive layer 211 and the second conductive layer 212 can be formed by an additive method, a subtractive method, etc. Step S22: Fig. 9 As shown, a plurality of blind holes 231 are provided at intervals on the first body 21 , and the blind holes 231 penetrate the first stacking structure 210 and the first conductive layer 211 .

[0102] In one embodiment, the blind hole 231 may be formed by laser drilling. During the laser drilling process, the second conductive layer 212 is not penetrated by the laser.

[0103] In one embodiment, the second conductive circuit layer 212 may be partially broken down.

[0104] Step S23: Fig.10 As shown, a third conductive layer 213 is disposed on the inner wall of the blind hole 231 to form a conductive hole 232 .

[0105] In one embodiment, the third conductive layer 213 at least covers the inner wall of the blind hole 231 , and extends to at least a portion of the surface of the first conductive layer 211 away from the first stacked structure 210 .

[0106] Step S24, as Fig.11 As shown, the first conductive layer 211 is etched to obtain the first conductive line 215 , and the second conductive layer 212 is etched to obtain the second conductive line 216 .

[0107] In one embodiment, the first conductive layer 211 and the second conductive layer 212 may be patterned by a pattern transfer process.

[0108] In one embodiment, the third conductive layer 213 may be surface treated, and a microstructure 214 may be formed on the inner wall of the third conductive layer 213 .

[0109] In one embodiment, a first solder resist layer 217 is formed on the surface of the first conductive circuit 215 and the second conductive circuit 216 away from the first stacking structure 110, and the first solder resist layer 217 can cover the exposed surface of the first conductive circuit 215 and the second conductive circuit 216; the conductive through hole 233 is not covered by the first solder resist layer 217, and at least a portion of the second conductive circuit 216 corresponding to the conductive through hole 233 is not covered by the first solder resist layer 217.

[0110] Step S25, as Fig.12 As shown, the conductive hole 232 is filled with solder paste 25 .

[0111] In one embodiment, the solder paste 25 may be provided by printing so that the solder paste 25 fills the conductive via 232 and overflows from the opening of the conductive via 232 to cover the surface of the conductive via 232 away from the first stacking structure 210 .

[0112] Step S26, as Fig.13 As shown, the second conductive circuit 216 and part of the third conductive layer 213 are removed to form a conductive through hole 233 penetrating the first body 21 , so that at least part of the solder paste 25 near the second conductive circuit 216 is exposed.

[0113] In one embodiment, a portion of the second conductive circuit 216 and the third conductive layer 213 is removed to form a first window 236 , and the first window 236 is connected to the conductive hole 232 to form a conductive through hole 233 .

[0114] In one embodiment, the portion of the second conductive circuit 216 not covered by the first solder resist layer 217 is removed to expose the bottom of the conductive hole 232, and the third conductive layer 213 at the bottom of the conductive hole 232 is further removed to expose the solder paste in the conductive hole 232. The conductive structure of the conductive hole 232 is changed from a blind hole to a through hole to obtain a conductive through hole 233.

[0115] In one embodiment, the second conductive circuit 216 and a portion of the third conductive layer 213 may be removed by laser cutting.

[0116] In one embodiment, the conductive via 233 includes a first end 234 and a second end 235. The first end 234 is disposed on a side of the conductive via 233 close to the first conductive line 215, and the second end 235 is disposed on a side of the conductive via 233 close to the second conductive line 216. In this embodiment, the cross-sectional area of ​​the first end 234 is greater than the cross-sectional area of ​​the second end 235.

[0117] Step S27, as Fig.14 As shown, after the conductive through hole 233 is formed, solder paste 25 is added to the second end 235 so that the added solder paste 25 overflows from the second end 235 in a direction away from the first stacking structure 210 and covers at least a portion of the surface of the second conductive line 216 away from the first stacking structure 210 .

[0118] In one embodiment, after the conductive through hole 233 is opened, the first body 21 is flipped 180 degrees, and solder paste 25 is added to one side of the second end 235 . The added solder paste 25 is connected and in contact with the solder paste 25 added into the conductive through hole 233 in the previous step through the second end 235 .

[0119] Step S28, as Fig.15 As shown, a second body 22 is provided, so that the first body 21 and the second body 22 are stacked, a welding gap 229 is provided between the first body 21 and the second body 22, so that the conductive through hole 233 is connected to the welding gap 229.

[0120] In one embodiment, the second body 22 may include a second stacking structure 220 , and a plurality of welding pads 221 are disposed on at least one side surface of the second stacking structure 220 . The plurality of welding pads 221 are disposed in the welding gap 229 .

[0121] In one embodiment, the first end portion 234 is connected to the welding gap 229 . Specifically, the first end portion 234 is directly opposite to the welding gap 229 and is connected to the space in the welding gap 229 to facilitate the flow of solder paste 25 during the subsequent heating process.

[0122] In one embodiment, one welding gap 229 is connected to at least two first end portions 234. In this embodiment, one welding gap 229 corresponds to two first end portions 234, and this structure can reduce the gap between the first body 11 and the second body 12.

[0123] In one embodiment, the second stacked structure 220 may be a multi-layer board, and the second stacked structure 220 may include at least one layer of substrate (e.g., PI), and a fifth conductive circuit 225 and a sixth conductive circuit 226 disposed on two opposite surfaces of the substrate, and a second solder resist layer 227 may be disposed on the surfaces of the fifth conductive circuit 225 and the sixth conductive circuit 226, and a plurality of welding gaps 229 may be separated by the second solder resist layer 227. In other embodiments, the second stacked structure 220 may be other multi-layer structures, for example, a multi-layer circuit board including inner conductive circuits or embedded components.

[0124] Step S29, as Fig.16 As shown, the solder paste 25 is heated by light, and after melting, the solder paste 25 flows into the welding gap 229 and solidifies to achieve welding of the first body 21 and the second body 22 .

[0125] In one embodiment, the solder paste 25 is filled in the conductive through hole 233 and overflows from the first end 234 and the second end 235 in a direction away from the first stacking structure 210; a heating light is used to irradiate the solder paste 25 on the side close to the second end 235, and the solder paste 25 overflowing the second end 235 is directly irradiated with the light and heated to melt. The melted solder paste 25 flows into the welding gap 229 through the first end 234 under the action of gravity and contacts the solder pad 221.

[0126] The melted solder paste 25 is solidified to achieve welding between the first body 21 and the second body 22 .

[0127] like Fig.17 As shown, a circuit board 2 is provided in the second embodiment of the present invention. The circuit board 2 includes a first body 21 , a second body 22 and solder paste 25 . The first body 21 and the second body 22 are stacked and soldered by the solder paste 25 .

[0128] The first body 21 includes a first stacking structure 210 and a first conductive circuit 215 and a second conductive circuit 216 disposed on two opposite surfaces of the first stacking structure 210. In one embodiment, the first stacking structure 210 may be a multilayer board, and the first stacking structure 210 may include at least two layers of substrate (such as PI), and an adhesive layer disposed between the two layers of substrate for connection. In other embodiments, the first stacking structure 210 may be other multilayer circuit structures, for example, a multilayer circuit board including embedded components. The first conductive circuit 215 and the second conductive circuit 216 are conductive materials, for example, copper. In one embodiment, the first body 21 also includes a first solder resist layer 217, and the first solder resist layer 217 may cover the exposed surfaces of the first conductive circuit 215 and the second conductive circuit 216.

[0129] A plurality of conductive through holes 233 are disposed at intervals on the first main body 21. The conductive through holes 233 penetrate the first main body 21. The conductive through holes 233 penetrate the first stacked structure 210, the first conductive circuit 215 and the second conductive circuit 216. A third conductive layer 213 is disposed on the inner wall of the conductive through hole 233. The third conductive layer 213 is electrically connected to the first conductive circuit 215 and the second conductive circuit 216. The third conductive layer 213 covers the surface of the first conductive circuit 215 near the periphery of the conductive through hole 233.

[0130] In one embodiment, the conductive via 233 includes a conductive hole 232 and a first window 236 . The conductive hole 232 penetrates the first conductive circuit 215 . The first window 216 penetrates the second conductive circuit 216 . The conductive hole 232 is connected to the first window 236 .

[0131] In one embodiment, the conductive via 233 is not covered by the first solder resist layer 217 , and at least a portion of the second conductive circuit 216 corresponding to the conductive via 233 is not covered by the first solder resist layer 217 .

[0132] The conductive via 233 includes a first end 234 and a second end 235. The first end 234 is disposed on a side of the conductive via 233 close to the first conductive line 215, and the second end 235 is disposed on a side of the conductive via 233 close to the second conductive line 216. The solder paste 25 is filled in the conductive via 233 and overflows from the first end 234 and the second end 235 in a direction away from the first stacking structure 210. The second end 235 is connected to the welding gap 229. In this embodiment, the cross-sectional area of ​​the first end 234 is greater than the cross-sectional area of ​​the second end 235.

[0133] The first body 21 and the second body 22 are stacked, a welding gap 229 is sandwiched between the first body 21 and the second body 22, and the conductive through hole 233 is connected to the welding gap 229. In one embodiment, the second body 22 may include a second stacking structure 220, and a plurality of solder pads 221 are disposed on at least one side surface of the second stacking structure 220, and the plurality of solder pads 221 are disposed in the welding gap 229. The second stacking structure 220 may be a multi-layer board, and the second stacking structure 220 may include at least one layer of substrate (such as PI), and a fifth conductive circuit 225 and a sixth conductive circuit 226 disposed on two opposite surfaces of the layer of substrate, and a second solder resist layer 227 may be disposed on the surface of the fifth conductive circuit 225 and the sixth conductive circuit 226, and a plurality of welding gaps 229 may be separated by the second solder resist layer 227, and one welding gap 229 may correspond to a plurality of first end portions 234. In other embodiments, the second stacking structure 220 may be other multi-layer structures, for example, a multi-layer circuit board including embedded components.

[0134] In addition, those skilled in the art may also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included in the scope of protection required by the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that: include: Providing a first body, the first body comprising a first stacking structure and a first conductive layer and a second conductive layer disposed on two opposite surfaces of the first stacking structure; A plurality of blind holes are provided at intervals on the first body, wherein the blind holes penetrate the first stacked structure and the first conductive layer, and the blind holes do not penetrate or partially penetrate the second conductive layer; Disposing a third conductive layer on the inner wall of the blind hole to form a conductive hole; Etching the first conductive layer to obtain a first conductive circuit, and etching the second conductive layer to obtain a second conductive circuit; Filling solder paste in the conductive hole; Removing a portion of the second conductive circuit and the third conductive layer to form a conductive through hole penetrating the first body, so that at least a portion of the solder paste near the second conductive circuit is exposed, the conductive through hole comprises a first end and a second end, the first end is arranged at a side of the conductive through hole near the first conductive circuit, the second end is arranged at a side of the conductive through hole near the second conductive circuit, the opening aperture of the first end is larger than the opening aperture of the second end, the solder paste is filled in the conductive through hole and overflows from the first end in a direction away from the first stacking structure; The first body is turned over 180 degrees, and solder paste is added to the second end, so that the added solder paste is connected and contacts with the solder paste added to the conductive through hole in the previous step through the second end, and the added solder paste overflows from the second end in a direction away from the first stacking structure; providing a second body, wherein a welding gap is provided between the first body and the second body, so that the first body and the second body are stacked and arranged, and at least two of the first ends are connected to the welding gap; and The solder paste is heated by light, and a heating light is used to irradiate the solder paste near the second end. After the solder paste melts, it flows into the welding gap through the first end and solidifies to achieve welding of the first body and the second body.

2. A circuit board, characterized in that: The circuit board is manufactured by the method for manufacturing a circuit board according to claim 1, and the circuit board comprises: A first body, the first body comprising a first stacking structure and a first conductive circuit and a second conductive circuit disposed on two opposite surfaces of the first stacking structure; a second body, the second body being stacked with the first body, and a welding gap being sandwiched between the first body and the second body; A conductive through hole, the conductive through hole passes through the first body and is connected to the welding gap, a plurality of the conductive through holes are arranged at intervals on the first body, the conductive through hole comprises a conductive hole and a first window, the conductive hole passes through the first conductive line, the first window passes through the second conductive line, the conductive hole is connected to the first window, the conductive through hole comprises a first end and a second end, the first end is arranged on a side of the conductive through hole close to the first conductive line, the second end is arranged on a side of the conductive through hole close to the second conductive line, and the opening aperture of the first end is larger than the opening aperture of the second end; and Solder paste is filled in the conductive through hole and the welding gap to weld the first body and the second body.

3. The circuit board according to claim 2, characterized in that: The solder paste is filled in the conductive through hole and overflows from the first end and the second end respectively in a direction away from the first stacking structure, and the first end is connected to the welding gap.

4. The circuit board according to claim 3, characterized in that: A first solder resist layer is disposed on a portion of the surface of the first conductive circuit and the second conductive circuit away from the first stacking structure.

Images