Circuit board and manufacturing method thereof
By creating grooves on the conductive pillars of the circuit board and filling them with solder paste, the problem of insufficient soldering strength is solved, and stable soldering of electronic components is achieved, making it suitable for miniaturized circuit board designs.
Patent Information
- Application Number
- CN202410480070.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-19
- Publication Date
- 2025-10-24
AI Technical Summary
In the existing technology, insufficient soldering strength is a common problem when electronic components are soldered onto circuit boards, leading to poor soldering.
Grooves are made on the conductive pillars of the circuit board and filled with solder paste. Electronic components are soldered to the solder paste and surface of the conductive pillars through solder balls, increasing the contact area and improving the bonding force.
By increasing the contact area between the tin and the conductive pillar, the welding strength is improved, ensuring a stable connection of electronic components.
Smart Images
Figure CN120835455A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of circuit board, and in particular to a circuit board and a manufacturing method thereof. BACKGROUND
[0002] With the rapid development of science and technology, high-density miniaturization has become a major development trend of electronic products, and the spacing between the solder pads on the corresponding circuit board for mounting various electronic components is becoming smaller and smaller. In the prior art, when the electronic components are soldered on the circuit board, the problem of poor soldering caused by insufficient soldering strength is prone to occur. SUMMARY
[0003] Therefore, it is necessary to provide a circuit board and a manufacturing method thereof capable of solving the above problems.
[0004] The first aspect of the present application provides a circuit board, comprising a circuit substrate, a plurality of conductive columns, a plurality of tin paste and an electronic component. The circuit substrate comprises a first substrate, the first substrate comprises a first substrate layer and a first conductor layer and a second conductor layer arranged on the opposite two surfaces of the first substrate layer, the first conductor layer comprises a plurality of connection pads, the second conductor layer is provided with an opening exposing the first substrate layer, the first substrate layer is provided with a plurality of through holes exposed in the opening, and a plurality of the connection pads are respectively exposed in a plurality of the through holes. A plurality of the conductive columns are accommodated in the opening and respectively pass through a plurality of the through holes and are connected with a plurality of the connection pads, the conductive columns are arranged away from the second conductor layer, and the surface of the conductive column away from the connection pad is provided with a groove. The tin paste is accommodated in the groove. The electronic component comprises a tin ball, the tin ball covers the surface of the conductive column away from the connection pad and is connected with the tin paste.
[0005] The second aspect of the present application provides a manufacturing method of a circuit board, comprising the following steps:
[0006] A circuit substrate is provided, the circuit substrate comprises a first substrate, the first substrate comprises a first substrate layer and a first conductor layer and a second conductor layer arranged on the opposite two surfaces of the first substrate layer;
[0007] A plurality of through holes are formed on the first substrate, the through holes pass through the second conductor layer and the first substrate layer, and expose part of the first conductor layer;
[0008] A conductive material is filled in the through holes, the conductive material fills a plurality of the through holes and covers the surface of the second conductor layer, and the conductive material is also connected with the first conductor layer;
[0009] Part of the conductive material is removed to form a plurality of conductive columns arranged at intervals, and a plurality of the conductive columns respectively fill a plurality of the filling pieces and are connected with the first conductor layer;
[0010] removing a portion of the second conductor layer so that the conductive pillars are separated from the second conductor layer;
[0011] forming a groove on a surface of the conductive column facing away from the first conductor layer;
[0012] Filling the groove with solder paste;
[0013] Making a plurality of connection pads on the first conductor layer, wherein the plurality of connection pads are connected to the plurality of conductive pillars in a one-to-one correspondence;
[0014] Installing electronic components on the plurality of conductive pillars, the electronic components comprising a plurality of solder balls, the plurality of solder balls being in one-to-one contact with the plurality of solder pastes;
[0015] The circuit substrate on which the electronic components are mounted is placed in a reflow furnace for heating, so that the solder balls and the solder paste are melted and combined.
[0016] In the circuit board and its manufacturing method provided in the embodiment of the present application, a conductive column connected to the connection pad is configured, a groove is opened on the conductive column, and solder paste is filled in the groove, and the electronic components are welded to the solder paste contained in the conductive column and the surface of the conductive column through solder balls, thereby increasing the contact area between the tin and the conductive column, which is conducive to improving the bonding force and thereby improving the welding strength. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a schematic cross-sectional view of a circuit substrate provided in one embodiment of the present application.
[0018] Figure 2 For Figure 1 The schematic cross-sectional view of the circuit substrate after a through hole is formed on the first substrate is shown.
[0019] Figure 3 For Figure 2 A schematic cross-sectional view of a through hole after a filling member is formed is shown.
[0020] Figure 4 For Figure 3 The cross-sectional view of the through hole after being filled with conductive material is shown.
[0021] Figure 5 To remove Figure 4 The schematic cross-sectional view of a portion of the conductive material after forming a conductive pillar is shown.
[0022] Figure 6 For Figure 5 The cross-sectional view of the conductive pillars shown is shown after solder paste is filled in the conductive pillars and connection pads are formed on the circuit substrate.
[0023] Figure 7 Fig. 1 is a schematic view of a circuit board according to an embodiment of the present application. Figure 6 Fig. 2 is a schematic view of a cross section of the circuit board shown in Fig. 1 after mounting electronic components on the conductor.
[0024] Figure 8 Fig. 3 is a schematic view of a structure of a circuit board according to an embodiment of the present application.
[0025] Explanation of main component symbols
[0026] Circuit substrate 10
[0027] First substrate 11
[0028] First base material layer 111
[0029] First conductor layer 112
[0030] Second conductor layer 113
[0031] Second substrate 12
[0032] Adhesive layer 13
[0033] Second base material layer 121
[0034] Third conductor layer 122
[0035] Via hole 110
[0036] Opening 120
[0037] Filling member 20
[0038] Conductive material 30
[0039] Conductive pillar 31
[0040] Groove 311
[0041] Solder paste 40
[0042] Connection pad 112a
[0043] Electronic component 50
[0044] Solder ball 51
[0045] Circuit board 100
[0046] The following detailed description will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0047] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.
[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the present application.
[0049] An embodiment of the present application provides a manufacturing method of a circuit board, comprising the following steps.
[0050] Step S1, referring to Figure 1 , a circuit substrate 10 is provided. The circuit substrate 10 comprises a first substrate 11. The first substrate 11 comprises a first substrate layer 111 and a first conductor layer 112 and a second conductor layer 113 arranged on two opposite surfaces of the first substrate layer 111. In the embodiment, the first conductor layer 112 and the second conductor layer 113 are circuit layers formed by patterned copper layers. In another embodiment, the first conductor layer 112 and the second conductor layer 113 are integral copper foils, and the first substrate 11 is a double-sided copper clad plate.
[0051] In some embodiments, the circuit substrate 10 further comprises a second substrate 12, and the second substrate 12 is bonded to the surface of the second conductor layer 113 through an adhesive layer 13. The second substrate 12 comprises a second substrate layer 121 and a third conductor layer 122 arranged in a stack. The adhesive layer 13 is arranged between and bonded to the second substrate layer 121 and the second conductor layer 113. In the embodiment, the third conductor layer 122 is a circuit layer formed by a patterned copper layer. In another embodiment, the third conductor layer 122 is an integral second substrate 12, and the second substrate 12 is a single-sided copper clad plate. The circuit substrate 10 is provided with an opening 120 penetrating through the third conductor layer 122, the second substrate layer 121 and the adhesive layer 13, and the opening 120 exposes part of the second conductor layer 113.
[0052] The materials of the first substrate layer 111 and the second substrate layer 121 can each be, but are not limited to, a prepreg (PP) containing glass fibers and epoxy resin, polyimide, polyethylene terephthalate, or polyethylene naphthalate, etc. The materials of the first conductor layer 112, the second conductor layer 113 and the third conductor layer 122 can each be, but are not limited to, gold, silver, etc.
[0053] Step S2, referring to Figure 2A plurality of through holes 110 are formed on the first substrate 11. The through holes 110 penetrate the second conductor layer 113 and the first substrate layer 111, and expose part of the first conductor layer 112. The plurality of through holes 110 are exposed in the openings 120, and the sidewalls of the through holes 110 are arranged in a staggered manner with the sidewalls of the openings 120, so as to reduce the risk of interference between the first substrate 11 and electronic components to be mounted subsequently. The through holes 110 are formed by a laser drilling or mechanical drilling process.
[0054] Step S3, please refer to Figure 3 A filler 20 is formed in the through hole 110, and the filler 20 is supported on the first conductor layer 112. There is a gap between the sidewall of the filler 20 and the sidewall of the through hole 110, that is, the filler 20 accommodated in the through hole 110 does not contact the first substrate layer 111 and the second conductor layer 113. The side surface of the filler 20 is beveled to increase the contact area between the filler 20 and the conductive pillar to be formed subsequently. In the present embodiment, the filler 20 is substantially trapezoidal.
[0055] In the present embodiment, the filler 20 is a tin paste. After the tin paste is filled into the through hole 110, the circuit substrate 10 is heated through a reflow oven, so that the tin paste is melted, and the bonding force between the tin paste and the first conductor layer 112 is improved. In another embodiment, the filler 20 is an adhesive, which has good adhesion and is conducive to fixing with the first conductor layer 112. In another embodiment, the filler 20 is a solid refrigerant, such as a fluoride or a high polymer, which is conducive to improving the heat dissipation performance.
[0056] Step S4, please refer to Figure 4 A conductive material 30 is filled in the through hole 110 and the opening 120. The conductive material 30 covers the plurality of fillers 20, and covers the surface of the second conductor layer 113 exposed in the opening 120. The conductive material 30 also contacts the plurality of connection pads 112a. The conductive material 30 can be but is not limited to a metal, such as copper, silver, etc. In the present embodiment, the conductive material 30 is copper. The conductive material 30 can be formed by an electroplating process.
[0057] Step S5, please refer to Figure 5 Part of the conductive material is removed to form a plurality of spaced-apart conductive pillars 31. The plurality of conductive pillars 31 respectively cover the plurality of fillers 20, and are connected with the first conductor layer 112. The conductive pillars 31 are arranged away from the sidewalls of the openings 120. In the present embodiment, along the sidewalls of the through holes 110, the conductive material located outside the through holes 110 is removed by a laser cutting process to form the plurality of conductive pillars 31. That is, the part of the conductive material located in the through hole 110 and aligned with the corresponding through hole 110 constitutes a conductive pillar 31.
[0058] In some embodiments, step S5 further comprises removing part of the second conductor layer 113, such that the conductive pillars 31 are spaced apart from the second conductor layer 113. In some embodiments, along the sidewall of the opening 120, the second conductor layer 113 exposed in the opening 120 is removed by a laser cutting process.
[0059] Step S6, please refer to Figure 5 A groove 311 is formed on the surface of the conductive pillar 31 facing away from the first conductor layer 112. The groove 311 is spaced apart from the filler 20, that is, the groove 311 is separated from the filler 20 by part of the conductive pillar 31. The sidewall of the groove 311 is beveled to increase the contact area between the conductive pillar 31 and the subsequent tin paste. In this embodiment, the groove 311 is substantially inverted trapezoidal. The groove 311 is formed by a laser drilling process.
[0060] Step S7, please refer to Figure 6 The tin paste 40 is filled in the groove 311. The tin paste 40 fills the groove 311. The surface of the tin paste 40 facing away from the bottom wall of the groove 311 is lower than or flush with the surface of the conductive pillar 31 facing away from the first conductor layer 112, so as to reduce the risk of molten tin paste overflowing into the space between the adjacent two conductive pillars 31 during subsequent reflow soldering. In another embodiment, the surface of the tin paste 40 facing away from the bottom wall of the groove 311 is slightly lower than the conductive pillar 31. The tin paste 40 can be filled in the groove 311 by a spraying process.
[0061] Step S8, please refer to Figure 6 A plurality of connection pads 112a are made on the first conductor layer 112. The plurality of conductive pillars 31 are in one-to-one correspondence with the plurality of connection pads 112a. In this embodiment, a laser cutting process is used to make a plurality of connection pads 112a on the first conductor layer 112. Compared with the etching process, the laser cutting process has higher precision and can make connection pads 112a with smaller pitch, which is beneficial to the miniaturization of the circuit board.
[0062] Step S9, please refer to Figure 7 The electronic component 50 is mounted on the plurality of conductive pillars 31. The electronic component 50 includes a plurality of tin balls 51, and the plurality of tin balls 51 are in one-to-one correspondence with the plurality of tin pastes 40. The electronic component 50 is mounted on the plurality of conductive pillars 31 by surface mounting technology. In some embodiments, the electronic component 50 is a chip.
[0063] Step S10, please refer to Figure 8 The circuit board 100 is obtained by placing the circuit board 10 with the electronic component 50 mounted thereon in a reflow oven and heating, so that the tin balls 51 and the tin pastes 40 are molten and combined.
[0064] During the reflow soldering process, the molten solder paste 40 is soldered to the sidewall of the recess 311, thereby improving the bonding force between the solder paste 40 and the conductive pillar 31. The molten solder ball 51 is soldered to the surface of the conductive pillar 31, thereby improving the bonding force between the solder ball 51 and the conductive pillar 31. In addition, the sidewall of the conductive pillar 31 increases the solder capacity, thereby facilitating the maintenance of the small spacing between the adjacent conductive pillars 31. When the molten solder overflows from the surface of the conductive pillar 31, the molten solder flows along the sidewall of the conductive pillar 31 into the space between the adjacent conductive pillars 31. When the amount of the molten solder is small, the molten solder can only cover the sidewall of the conductive pillar 31 without flowing into the space between the adjacent conductive pillars 31.
[0065] In some embodiments, the method for manufacturing the circuit board further comprises the step of forming a solder resist layer (not shown) on the surface of the circuit board, wherein the solder resist layer covers the surface of the third conductor layer facing away from the second substrate layer and the surface of the first conductor layer facing away from the first substrate layer.
[0066] In some embodiments, the method for manufacturing the circuit board further comprises the step of filling the adhesive into the opening, wherein the adhesive fills the gap between the adjacent conductive pillars and the gap between the conductive pillar and the sidewall of the opening, thereby improving the stability.
[0067] Referring to Figure 8 In an embodiment, a circuit board 100 is provided, which comprises a circuit substrate 10, a plurality of conductive pillars 31, a plurality of solder pastes 40, and electronic components 50. The circuit substrate 10 comprises a first substrate 11, which comprises a first substrate layer 111 and a first conductor layer 112 and a second conductor layer 113 arranged on opposite surfaces of the first substrate layer 111. The first conductor layer 112 comprises a plurality of connection pads 112a arranged at intervals. The second conductor layer 113 is provided with an opening 120 exposing the first substrate layer 111. The first substrate layer 111 is provided with a plurality of through holes 110 exposing the plurality of connection pads 112a, and the plurality of through holes 110 are exposed in the opening 120. The conductive pillars 31 are accommodated in the opening 120 and pass through the through holes 110 to connect with the connection pads 112a, and the conductive pillars 31 are arranged away from the second conductor layer 113. The surface of the conductive pillar 31 facing away from the connection pad 112a is provided with a recess 311, and the solder paste 40 is accommodated in the recess 311. The electronic components 50 comprise a plurality of solder balls 51, and the solder balls 51 cover at least part of the surface of the conductive pillar 31 facing away from the connection pad 112a and connect with the solder paste 40.
[0068] In some embodiments, the circuit board 100 further comprises a plurality of fillers 20. The fillers 20 are arranged in the conductive pillars 31 and supported on the connection pads 112a. In some embodiments, the fillers 20 are solder pastes. In other embodiments, the fillers 20 are adhesives or solid coolants.
[0069] In some embodiments, the circuit board 100 further comprises a second substrate 12 and an adhesive layer 13, the second substrate 12 is bonded to the surface of the second conductor layer 113 away from the first substrate layer 111 through the adhesive layer 13. The opening 120 extends through the second substrate 12 and the adhesive layer 13, and the plurality of conductive pillars 31 are accommodated in the opening 120 and arranged away from the sidewall of the opening 120.
[0070] In some embodiments, the side surface of the tin paste 40 and the side surface of the filling piece 20 are both bevels.
[0071] In the circuit board and the manufacturing method thereof provided by the embodiments of the present application, the conductive pillar 31 connected with the connecting pad 112a is configured, the groove 311 is formed on the conductive pillar 31, the tin paste 40 is filled in the groove 311, and the electronic component 50 is welded with the tin paste 40 accommodated in the conductive pillar 31 and the surface of the conductive pillar 31 through the tin ball 51, so that the contact area between the tin and the conductive pillar 31 is increased, the bonding force is improved, and the welding strength is improved. In addition, the conductive pillar 31 and the connecting pad 112a are manufactured by the laser cutting process, so that the spacing between the adjacent connecting pads 112a / conductive pillars 31 is reduced, and miniaturization is facilitated.
[0072] The above only discloses the preferred embodiments of the present application, and of course cannot limit the present application, so the equivalent changes made according to the present application still belong to the scope covered by the present application.
Claims
1. A circuit board, characterized by, The circuit board comprises: a circuit substrate comprising a first substrate, the first substrate comprising a first substrate layer and a first conductor layer and a second conductor layer disposed on two opposite surfaces of the first substrate layer, the first conductor layer comprising a plurality of connection pads, the second conductor layer being provided with an opening exposing the first substrate layer, the first substrate layer being provided with a plurality of through holes exposed in the opening, the plurality of connection pads being respectively exposed in the plurality of through holes; a plurality of conductive pillars, the plurality of conductive pillars being accommodated in the opening and respectively passing through the plurality of through holes and being connected with the plurality of connection pads, the conductive pillars being disposed away from the second conductor layer, the surface of the conductive pillars facing away from the connection pads being provided with a groove; solder paste, the solder paste being accommodated in the groove; an electronic component, the electronic component comprising a plurality of solder balls, the plurality of solder balls covering the surface of the conductive pillars facing away from the connection pads and being connected with the solder paste.
2. The circuit board of claim 1, wherein, The circuit board further comprises a filling piece, the filling piece being disposed in the conductive pillar and being supported on the connection pad.
3. The circuit board of claim 2, wherein, The filling piece is solder paste.
4. The circuit board of claim 2, wherein, The filling piece is an adhesive.
5. The circuit board of claim 1, wherein, The circuit board further comprises a second substrate and an adhesive layer, the second substrate being bonded to the surface of the second conductor layer facing away from the first substrate layer through the adhesive layer, the opening extending through the adhesive layer and the second substrate.
6. A method of manufacturing a circuit board, characterized by, The method comprises the following steps: providing a circuit substrate comprising a first substrate, the first substrate comprising a first substrate layer and a first conductor layer and a second conductor layer disposed on two opposite surfaces of the first substrate layer; forming a plurality of through holes on the first substrate, the through holes penetrating the second conductor layer and the first substrate layer and exposing part of the first conductor layer; filling conductive material in the through holes, the conductive material filling the plurality of through holes and covering the surface of the second conductor layer, the conductive material also being connected with the first conductor layer; removing part of the conductive material to form a plurality of conductive pillars arranged at intervals, the plurality of conductive pillars respectively filling the plurality of through holes and being connected with the first conductor layer; removing part of the second conductor layer to arrange the conductive pillars away from the second conductor layer; forming a groove on the surface of the conductive pillars facing away from the first conductor layer; filling solder paste in the groove; forming a plurality of connection pads on the first conductor layer, the plurality of connection pads being connected with the plurality of conductive pillars one by one; mounting an electronic component on the plurality of conductive pillars, the electronic component comprising a plurality of solder balls, the plurality of solder balls being respectively connected with the plurality of solder paste one by one; placing the circuit substrate with the electronic component in a reflow oven to heat, so that the solder balls and the solder paste are fused and combined.
7. The method of manufacturing a circuit board according to claim 6, wherein Before the step of "filling conductive material in the through holes", the method further comprises the following steps: forming a filling piece in the through hole, the filling piece being supported on the first conductor layer; wherein, after forming the plurality of conductive pillars, the plurality of conductive pillars respectively cover the plurality of filling pieces.
8. The method of manufacturing a circuit board according to claim 7, wherein The filling piece is solder paste.
9. The method of manufacturing a circuit board according to claim 7, wherein The filling piece is an adhesive.
10. The method of manufacturing a circuit board according to claim 6, wherein The plurality of connection pads are formed on the first conductor layer by a laser cutting process.