Circuit board, multilayer circuit board and light-emitting module

Abstract

The invention provides a circuit board, a multi-layer circuit board and a light-emitting module. The circuit board comprises a conducting layer, and the conducting layer is provided with a plurality of conducting circuits and a polymer arranged adjacent to at least one conducting circuit; the polymer contains carboxyl; the adhesive force of the polymer and the metal can be improved, and the yield of the circuit board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a circuit board, a multi-layer circuit board, and a light-emitting module having the circuit board or the multi-layer circuit board. Background Art

[0002] The conductive layer in the existing circuit board is generally formed by first coating a layer of UV glue or embossed glue on the substrate layer, and then attaching the mold to the substrate. After curing and demolding, a conductive groove is formed at the UV glue or embossed glue, and finally a conductive material is deposited in the conductive groove to form a conductive circuit. Among them, the side where the substrate layer is located is the bottom, and the side where the conductive layer is located is the top. In order to facilitate demolding, the conductive groove is generally formed in the shape of an inverted trapezoid with a larger top and a smaller bottom. However, the bonding adhesion between the conductive material itself and the UV glue or embossed glue is average, and because the conductive groove is in the shape of an inverted trapezoid with a larger top and a smaller bottom, it is impossible to limit the conductive circuit, resulting in a reduced bonding adhesion between the formed conductive circuit and the conductive groove, resulting in a low final yield. Summary of the invention

[0003] The object of the present invention is to provide a circuit board, a multi-layer circuit board, and a light-emitting module having the circuit board or the multi-layer circuit board.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a circuit board, comprising a conductive layer, wherein the conductive layer has a plurality of conductive lines and a polymer arranged adjacent to at least one conductive line; the polymer contains a carboxyl group.

[0005] As a further improved technical solution of the present invention, the mass proportion of the carboxyl groups in the polymer is 0.1% to 5%.

[0006] As a further improved technical solution of the present invention, the polymer further comprises at least one of amino, hydroxyl, methacryloxy functional silane and γ-glycidyloxypropyltrimethoxysilane.

[0007] As a further improved technical solution of the present invention, the amino group accounts for 0.5% to 15% of the mass of the polymer; the hydroxyl group accounts for 0.5% to 5% of the mass of the polymer; the methacryloxy functional silane accounts for 1% to 3% of the mass of the polymer; and the γ-glycidyloxypropyltrimethoxysilane accounts for 1% to 3% of the mass of the polymer.

[0008] As a further improved technical solution of the present invention, the polymer is a light-curing adhesive after light curing or a heat-curing adhesive after heat curing.

[0009] As a further improved technical solution of the present invention, the conductive circuit is a copper conductive circuit.

[0010] As a further improved technical solution of the present invention, the circuit board also includes a substrate layer, the conductive layer includes a lower surface connected to the substrate layer and an upper surface opposite to the lower surface; the lower edge located at the lower surface in the cross section of the conductive circuit is arc-shaped.

[0011] As a further improved technical solution of the present invention, the circuit board also includes a substrate layer, the conductive layer includes a lower surface connected to the substrate layer, and an upper surface opposite to the lower surface; the cross-section of the conductive circuit has an upper edge located at the upper surface, a lower edge located at the lower surface, and a side edge connecting the upper edge and the lower edge at one end on the same side, and at least one of the side edges has an angle greater than 90° with the upper edge.

[0012] As a further improved technical solution of the present invention, conductive lines with different widths correspond to different thicknesses, and the width of the conductive line is inversely proportional to the thickness.

[0013] As a further improved technical solution of the present invention, at least two conductive circuits have different widths, and the thickness of the conductive circuit with a larger width is not greater than the thickness of the conductive circuit with a smaller width.

[0014] As a further improved technical solution of the present invention, the circuit board also includes a substrate layer, the conductive layer includes a lower surface connected to the substrate layer and an upper surface opposite to the lower surface; the lower surface of the conductive circuit has an adhesion promoting layer.

[0015] As a further improved technical solution of the present invention, the circuit board further includes a thermally conductive adhesive layer connected to the lower surface of the conductive layer and a substrate layer connected to the thermally conductive adhesive layer; the thermally conductive adhesive layer includes:

[0016] Epoxy resin, wherein the epoxy resin accounts for 20%-75% of the mass of the thermal conductive adhesive layer;

[0017] Heat dissipation powder, the heat dissipation powder accounts for 5%-50% of the mass of the thermal conductive adhesive layer;

[0018] Modified propane derivatives and / or γ-glycidyloxypropyltrimethoxysilane, wherein the modified propane derivative accounts for 10%-30% by weight of the thermally conductive adhesive layer, and the γ-glycidyloxypropyltrimethoxysilane accounts for 1%-5% by weight of the thermally conductive adhesive layer;

[0019] Mercapto derivatives and / or toughened elastomeric resins, wherein the mass of mercapto derivatives accounts for 5%-10% of the thermally conductive adhesive layer, and the mass of toughened elastomeric resin accounts for 5%-20% of the thermally conductive adhesive layer.

[0020] As a further improved technical solution of the present invention, the circuit board further includes a heat-conducting insulating layer located between the heat-conducting adhesive layer and the substrate layer.

[0021] To achieve the above-mentioned purpose of the invention, the present invention also provides a multi-layer circuit board, which includes at least two stacked circuit boards mentioned above; there is a connecting hole between two adjacent conductive layers, and an electrical connection column is located in the connecting hole to electrically connect the two conductive layers.

[0022] In order to achieve the above-mentioned object of the invention, the present invention further provides a light-emitting module, which includes the above-mentioned circuit board or multi-layer circuit board.

[0023] The beneficial effects of the present invention are as follows: the polymer of the conductive layer in the circuit board of the present invention is configured to contain a carboxyl group (—COOH); on the one hand, the oxygen atom in the carboxyl group contains unbonded electrons, which can cooperate with the empty orbits of the ions on the metal surface to form a monodentate, bidentate, or bridged coordination bond adsorption, thereby improving the adhesion between the polymer and the metal. At the same time, a thin oxide film is often easily formed on the metal surface, resulting in poor adhesion of the metal, and the carboxyl group is acidic and will react with the metal oxide film or the metal to micro-etch the metal surface, further improving the adhesion between the metal and the polymer, that is, it can improve the bonding adhesion between the polymer and the conductive circuit, and improve the yield rate of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of a circuit board in a first embodiment of the present invention;

[0025] Figure 2 Is prepared Figure 1 Step diagram of the circuit board shown;

[0026] Figure 3 is a schematic structural diagram of a circuit board in a second embodiment of the present invention;

[0027] Figure 4 is a schematic structural diagram of a circuit board in a third embodiment of the present invention;

[0028] Figure 5 is a schematic structural diagram of a circuit board in a fourth embodiment of the present invention;

[0029] Figure 6 Is prepared Figure 5 Step diagram of the circuit board shown;

[0030] Figure 7 is a schematic structural diagram of a circuit board in a fifth embodiment of the present invention;

[0031] Figure 8is a schematic structural diagram of a multi-layer circuit board in a specific embodiment of the present invention;

[0032] Fig. 9 It is a schematic structural diagram of a multi-layer circuit board in another specific embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below in conjunction with the various embodiments shown in the accompanying drawings. Figures 1 to 9 It is shown as a preferred embodiment of the present invention. However, it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformation or replacement of functions, methods, or structures made by ordinary technicians in the field according to these embodiments shall fall within the protection scope of the present invention.

[0034] Please refer to Figure 1 As shown, a circuit board 10 in the first embodiment of the present invention is shown, and the circuit board 10 includes a conductive layer 1, and the conductive layer 1 has a plurality of conductive lines 11 and a polymer 12 disposed adjacent to at least one conductive line 11. In this embodiment, the conductive layer 1 includes the conductive lines 11 and the polymer 12, and the polymer 12 forms a patterned conductive groove, and the conductive lines 11 are formed in the conductive groove. Of course, this is not limited to this, and in other embodiments, only part of the conductive lines 11 in the conductive layer 1 can be formed in the conductive groove formed by the polymer 12, and the other conductive lines 11 can be prepared by other line forming processes in the prior art, such as etching.

[0035] In a specific embodiment, the conductive circuit 11 is a copper conductive circuit, which can reduce the cost of the circuit board 10 and has good conductivity. Of course, it is not limited to this. In other embodiments, the conductive circuit 11 can also be a conductive metal such as a silver conductive circuit, a conductive non-metal, a conductive alloy, or the like.

[0036] Furthermore, the polymer 12 contains a carboxyl group (—COOH). On the one hand, the oxygen atom in the carboxyl group contains unbonded electrons, which can cooperate with the empty orbital of the ions on the metal surface to form a monodentate, bidentate, or bridged coordination bond adsorption, thereby improving the adhesion between the polymer 12 and the metal. At the same time, a thin oxide film is often easily formed on the metal surface, resulting in poor adhesion of the metal. The carboxyl group is acidic and will react with the metal oxide film or metal to micro-etch the metal surface, further improving the adhesion between the metal and the polymer 12, that is, it can improve the bonding adhesion between the polymer 12 and the conductive circuit 11, and improve the yield rate of the circuit board 10.

[0037] Furthermore, the mass proportion of the carboxyl group in the polymer 12 is 0.1% to 5%, which can avoid the carboxyl group content being too low, which reduces the adhesion to the metal, and can also avoid the carboxyl group content being too high, which affects the water boiling performance and the film separation force being too large.

[0038] Specifically, infrared spectroscopy or nuclear magnetic resonance hydrogen spectroscopy can be used to qualitatively detect whether the polymer 12 contains carboxyl groups. Alternatively, the polymer 12 can be dissolved and then detected by titration (0.2-5 mgKOH / g).

[0039] In a specific embodiment, the polymer 12 contains at least one of 2-hydroxyethyl methacrylate phosphate, 2-hydroxyethyl methacrylate phosphate, alkyl acrylate phosphate, and multifunctional acidic acrylate, and the carboxyl group refers to the carboxyl group in 2-hydroxyethyl methacrylate phosphate, 2-hydroxyethyl methacrylate phosphate, alkyl acrylate phosphate, and multifunctional acidic acrylate. Of course, this is not limited to this.

[0040] Furthermore, the polymer 12 further includes at least one of hydroxyl, methacryloxy functional silane, and γ-glycidyloxypropyltrimethoxysilane, which can further improve the adhesion between the polymer 12 and the metal, that is, the bonding adhesion between the polymer 12 and the conductive circuit 11 can be improved, thereby improving the yield rate of the circuit board 10.

[0041] The hydroxyl group has strong polarity and can easily form strong hydrogen bonds on the metal surface. It can also coordinate with the empty orbitals of ions on the metal surface to form monodentate, bidentate, or bridging coordination bonds, thereby enhancing the bonding strength between the polymer 12 and the metal surface, that is, enhancing the bonding strength between the polymer 12 and the copper conductive circuit, thereby improving the yield rate of the circuit board 10.

[0042] Furthermore, the mass proportion of the hydroxyl group in the polymer 12 is 0.5% to 5%, which can avoid the hydroxyl content being too low, which reduces the adhesion to the metal, and can also avoid the hydroxyl content being too high, which affects the water boiling performance and the film separation force being too large.

[0043] Specifically, infrared spectroscopy or nuclear magnetic resonance hydrogen spectroscopy can be used to qualitatively detect whether the polymer 12 contains hydroxyl groups. Alternatively, the polymer 12 can be dissolved and then the carboxyl groups can be quantitatively detected by titration (1-5 mgKOH / g).

[0044] In a specific embodiment, the polymer 12 contains at least one of hydroxypropyl acrylate, hydroxyethyl acrylate and hydroxyethyl methacrylate, and the hydroxyl group mentioned above refers to the hydroxyl group in hydroxypropyl acrylate, hydroxyethyl acrylate and hydroxyethyl methacrylate. Of course, it is not limited to this.

[0045] The methacryloxy functional silane and γ-glycidyloxypropyltrimethoxysilane, as coupling agents, can form covalent bonds with the molecules on the surface of the inorganic metal, and can obtain good interface bonding. At the same time, the coupling agent can connect the inorganic metal with the organic glue, thereby greatly improving the adhesion between the polymer 12 and the inorganic metal, that is, enhancing the adhesion strength between the polymer 12 and the copper conductive line 11, and improving the yield rate of the circuit board 10.

[0046] The mass proportion of the methacryloxy functional silane in the polymer 12 is 1% to 3%, and the mass proportion of the γ-glycidyloxypropyltrimethoxysilane in the polymer 12 is 1% to 3%. This can prevent the coupling agent content from being too low, which affects the adhesion of the metal, and can also prevent the coupling agent content from being too high, which affects the curing and molding of the polymer.

[0047] Furthermore, in a specific embodiment, the polymer 12 is a light-cured photocurable adhesive, which can improve the stability of the shape / size of the formed conductive groove, facilitate the linearity / size control of the conductive line 11, and improve the stability of the circuit board 10. Of course, this is not limited to this, and in other embodiments, the polymer 12 can also be a heat-cured thermal adhesive.

[0048] Furthermore, the circuit board 10 also includes a thermally conductive adhesive layer 2 connected to the lower surface of the conductive layer 1, and a substrate layer 3 connected to the thermally conductive adhesive layer 2. In this embodiment, the substrate layer 3 is a heat dissipation plate, such as a non-metallic plate or a metal plate such as a BT board / PET board. The conductive layer 1 is connected to the substrate layer 3 through the thermally conductive adhesive layer 2, and at the same time, the heat dissipation of the conductive layer 1 can be achieved. The conductive layer 1 includes a lower surface connected to the substrate layer 3 and an upper surface opposite to the lower surface, and the conductive circuit 11 is exposed outward from the upper surface. The lower edge 111 located at the lower surface in the cross section of the conductive circuit 11 is arc-shaped. It is possible to increase the contact area between the conductive circuit 11 and the thermally conductive adhesive layer 2, thereby improving the connection strength between the conductive circuit 11 and the substrate layer 3.

[0049] In a specific embodiment, the lower edge 111 located at the lower surface in the cross section of the conductive circuit 11 is in a downward convex arc shape. Of course, it is not limited to this. It is known that the above-mentioned conductive circuit 11 is exposed outward from the upper surface means that when there is only one layer of the circuit board 10, the conductive circuit 11 is exposed outward from the upper surface. In the case of a multi-layer circuit board 20 stacked, the conductive circuit 11 is exposed from the upper surface toward the circuit board 10 stacked thereon.

[0050] Furthermore, the cross section of the conductive circuit 11 also has an upper edge 112 located at the upper surface, and two side edges 113 connecting the upper edge 112 and the lower edge 111 located at one end of the same side, that is, the cross section of the conductive circuit 11 is a quadrilateral. Among them, the angle α between at least one of the side edges 113 and the upper edge 112 is greater than 90°, and the conductive slot 13 can limit the conductive circuit 11, improve the combination stability between the conductive circuit 11 and the conductive slot 13, and improve the yield rate of the circuit board 10.

[0051] In a specific embodiment, the angle α between the two side edges 113 and the upper edge 112 is greater than 90°, that is, the cross-section of the conductive circuit 11 is a trapezoidal structure that is small at the top and large at the bottom. In the corresponding direction, the conductive groove 13 is also a trapezoidal structure that is small at the top and large at the bottom, which can limit the conductive circuit 11, improve the combination stability between the conductive circuit 11 and the conductive groove 13, and improve the yield rate of the circuit board 10.

[0052] In this embodiment, the side edge 113 is in a straight line shape. Of course, this is not limiting, and the side edge 113 can also be configured as: at least one side edge 113a is in an arc shape that bulges outward in a direction away from the center of the cross section. It can further limit the conductive circuit 11, improve the combination stability between the conductive circuit 11 and the conductive slot 13; at the same time, increase the cross-sectional area of ​​the conductive circuit 11, improve the conductivity of the conductive circuit 11, and improve the yield rate of the circuit board 10. Figure 3 As shown, in the second embodiment of the present invention, the two side edges 113a are both in an arc shape convex toward a direction away from the center of the cross section.

[0053] For further information, see Figure 1 As shown, in this embodiment, the upper edge 112 and the upper surface are located in the same plane; the distance h1 between the lower edge 111 and the upper edge 112 is smaller than the distance h2 between the lower surface and the upper surface, that is, the thickness of the conductive circuit 11 is smaller than the thickness of the polymer 12, so as to avoid bridging between adjacent conductive circuits 11. Of course, this is not limited to this. Figure 4As shown, in the third embodiment, the upper edge 112 and the upper surface are located in the same plane; the distance h1 between the lower edge 111 and the upper edge 112 and the distance h2 between the lower surface and the upper surface satisfy: 0≤h1-h2<10μm, that is, the lower edge 111 is flush with the lower surface or protrudes from the lower surface, and the protrusion height protruding from the lower surface is less than 10μm, on the basis of enhancing the conductivity of the conductive circuit 11, it can also avoid bridging between adjacent conductive circuits 11, avoid the infiltration of the polymer 12, and avoid the short circuit of the conductive circuit 11. That is, the distance h1 between the lower edge 111 and the upper edge 112 can be less than, equal to, or greater than the distance h2 between the lower surface and the upper surface.

[0054] Furthermore, the maximum distance h between the lower edge 111 and the upper edge 112 is max The minimum distance d between the two side edges 113 min The ratio is not less than 0.5 to ensure the conductivity of the conductive circuit 11.

[0055] It should be noted that, in the embodiment where the lower edge 111 is in a downwardly convex arc shape, the maximum distance h between the lower edge 111 and the upper edge 112 is max It refers to the distance between the lowest point of the lower edge 111 and the upper edge 112, that is, the maximum thickness value of the conductive circuit 11 at a specific cross section. In the embodiment where the cross section of the conductive circuit 11 is a trapezoid, the minimum distance d between the two side edges 113 is min It refers to the length of the upper edge 112 .

[0056] Furthermore, the roughness of the upper surface is less than that of the lower surface, which can meet the requirement of the flatness of the upper surface of the circuit board 10. Of course, this is not limited to this, and in other embodiments, the roughness of the upper surface can also be greater than that of the lower surface to meet the roughness requirement of the circuit board 10.

[0057] Furthermore, the overall roughness Ra1 of the upper surface is in the range of 0.3 μm-5 μm.

[0058] Furthermore, the lower surface of the conductive circuit 11 has an adhesion promoting layer for improving the adhesion of the lower surface of the conductive circuit 11. Specifically, the adhesion promoting layer can be formed by increasing the roughness or viscosity of the lower surface of the conductive circuit 11 through a process such as browning or grinding the lower surface of the conductive circuit 11, thereby increasing the adhesion between the conductive circuit 11 and the thermally conductive adhesive layer 2, thereby improving the conductive performance and production yield.

[0059] Specifically, through the browning process, the lower surface of the conductive circuit 11 undergoes a chemical reaction to form an adhesion promoting layer to increase adhesion. Through the roughening process, the bonding area of ​​the lower surface of the conductive circuit 11 can be increased to increase adhesion and form the adhesion promoting layer.

[0060] Specifically, the adhesion between the conductive layer 1 and the thermal conductive adhesive layer 2 is not less than 5B.

[0061] Furthermore, at least two conductive circuits have different widths, and the thickness of the conductive circuit with a larger width is not greater than the thickness of the conductive circuit with a smaller width, so as to ensure the overall conductive performance.

[0062] Please refer to Figure 1 As shown, in this embodiment, the conductive circuits 11 with different widths have different corresponding thicknesses, and the width d of the conductive circuit 11 is inversely proportional to the thickness h. That is, the larger the width d of the conductive circuit 11, the thinner the thickness h of the corresponding conductive circuit 11 to ensure the conductive performance.

[0063] It should be noted that when the angle between the two side edges 113 and the upper edge 112 in the cross section of the conductive circuit 11 is 90°, the width d of the conductive circuit 11 is the distance between the two side edges 113 in the cross section of the conductive circuit 11. When the angle between at least one of the side edges 113 and the upper edge 112 is greater than 90°, it can be seen that the distance between the two side edges 113 gradually increases in the downward direction perpendicular to the conductive layer 1. The comparison of the width of the conductive circuit 11 is based on the same plane parallel to the upper surface of the conductive layer 1. The width of the conductive circuit 11 in the plane is the distance between the two side edges 113 and the two intersections of the plane.

[0064] Furthermore, the thickness difference between the conductive circuits 11 with different widths is no more than 9 μm, thereby reducing the difference in conductivity between the conductive circuits 11, improving the yield of the circuit board 10, and ensuring the stability of the conductive performance.

[0065] Specifically, the thermally conductive adhesive layer 2 includes epoxy resin, heat dissipation powder, modified propane derivatives and / or γ-glycidyloxypropyl trimethoxysilane, mercapto derivatives and / or toughened elastomer resin. By adding modified propane derivatives and / or γ-glycidyloxypropyl trimethoxysilane to the thermally conductive adhesive layer 2, the thermally conductive adhesive layer 2 can be connected to inorganic metals and organic materials at the same time, so that the thermally conductive adhesive layer can connect the conductive layer 1 to the substrate layer 3.

[0066] The epoxy resin accounts for 20%-75% of the mass of the thermally conductive adhesive layer 2 . The thermally conductive adhesive layer 2 is mainly composed of the epoxy resin. The epoxy resin can make the thermally conductive adhesive layer 2 have heat resistance, pressure resistance and insulation properties.

[0067] Specifically, the epoxy resin is bisphenol A epoxy resin, but is not limited thereto.

[0068] The heat dissipation powder accounts for 5%-50% of the mass of the heat conductive adhesive layer 2. The heat dissipation powder can make the heat conductive adhesive layer 2 have a certain thermal conductivity, which is beneficial to the heat dissipation of the conductive layer 1.

[0069] Specifically, the heat dissipation powder can be nano-aluminum oxide or nano-aluminum nitride. Of course, it is not limited thereto.

[0070] The modified propane derivative accounts for 10%-30% of the mass of the thermally conductive adhesive layer 2 , which can adjust the viscosity of the thermally conductive adhesive layer 2 finally formed and improve the adhesion between the thermally conductive adhesive layer 2 and the conductive layer 1 and the substrate layer 3 .

[0071] The mass proportion of the γ-glycidyloxypropyltrimethoxysilane in the thermally conductive adhesive layer 2 is 1%-5%, which can adjust the viscosity of the thermally conductive adhesive layer 2 formed finally, and improve the bonding force between the thermally conductive adhesive layer 2 and the conductive layer 1 and the substrate layer 3 .

[0072] The mercapto derivative accounts for 5% to 10% of the mass of the thermally conductive adhesive layer 2 , which can improve the acid and alkali resistance of the thermally conductive adhesive layer 2 formed finally, and can also improve the flexibility of the thermally conductive adhesive layer 2 .

[0073] The toughened elastomer resin accounts for 5% to 20% of the mass of the thermally conductive adhesive layer 2 , which can improve the flexibility of the thermally conductive adhesive layer 2 .

[0074] Please combine Figure 2 FIG. 1 is a specific embodiment of a method for preparing the circuit board 10 in the first embodiment of the present invention. It is understood that the method for preparing the circuit board 10 in the first embodiment of the present invention is not limited thereto.

[0075] Specifically, the preparation method comprises the following steps:

[0076] A photocurable adhesive is coated on a carrier 4, and then a polymer 12 having a patterned conductive groove 13 is formed by photocuring, and the carrier 4 corresponding to the conductive groove 13 is exposed outward from the conductive groove 13, that is, the conductive groove 13 passes through the photocurable adhesive;

[0077] By filling copper powder in the conductive groove 13 and sintering to form a copper conductive line 11, a conductive layer 1 is formed;

[0078] A heat-conducting adhesive layer 2 and a substrate layer 3 are sequentially arranged on the lower surface of the conductive layer 1 away from the carrier 4;

[0079] The carrier board 4 is removed to form the circuit board 10 .

[0080] The components of the polymer 12 are as described above and will not be elaborated herein.

[0081] Specifically, the overall roughness Ra1 of the side of the carrier 4 connected to the polymer 12 is in the range of 0.3 μm-5 μm, so that the overall roughness Ra1 of the upper surface of the finally formed circuit board 10 is in the range of 0.3 μm-5 μm.

[0082] Of course, this is not limited to the above. In other embodiments, the carrier board 4 can also be directly used as the base material layer of the final circuit board 10, that is, copper powder is filled in the conductive groove 13 and sintered to form the copper conductive line 11, and the circuit board is formed after the conductive layer 1 is formed. In this case, there is no need to separately set the thermal conductive adhesive layer 2 and the base material layer 3 on the lower surface of the conductive layer 1 away from the carrier board 4, and there is no need to remove the carrier board 4.

[0083] Meanwhile, the conductive groove 13 may be filled with silver paste and sintered to form a silver conductive circuit, or other conductive metals or conductive non-metals may be filled to form the conductive circuit.

[0084] Combination Figure 2 As shown, when the side where the carrier 4 is located is at the bottom, the conductive slot 13 is in an inverted trapezoidal shape that is larger at the top and smaller at the bottom, and the side of the conductive circuit 11 away from the carrier 4 is in an arc shape that bulges outwards toward the side away from the carrier 4. Therefore, in the circuit board 10 that is finally formed after flipping, the conductive circuit 11 is in a trapezoidal shape that is smaller at the top and larger at the bottom, and the lower edge 111 of the cross section of the conductive circuit 11 is in an arc shape that bulges outwards.

[0085] Please refer to Figure 5 As shown, it is a circuit board 10c in the fourth embodiment of the present invention. The difference between the circuit board 10c in the fourth embodiment of the present invention and the circuit board 10 in the first embodiment is that the substrate layer 3c is a metal plate, and the circuit board 10c also includes a thermally conductive insulating layer 5 located between the thermally conductive adhesive layer 2 and the substrate layer 3c.

[0086] The thermally conductive insulating layer 5 may be a thermally conductive insulating layer 5 in the prior art, which will not be described in detail herein.

[0087] Corresponding, combined Figure 6As shown, the difference between the preparation method of the circuit board 10c in the fourth embodiment and the preparation method of the circuit board 10 in the first embodiment is that after the conductive layer 1 is formed, a thermally conductive adhesive layer 2, a thermally conductive insulating layer 5 and a substrate layer 3c are sequentially arranged on the lower surface of the conductive layer 1 away from the carrier 4.

[0088] The fourth embodiment of the present invention is the same as the first embodiment except for the above differences, and will not be described in detail here.

[0089] Please refer to Figure 7 As shown, a circuit board 10d in the fifth embodiment of the present invention is shown. The circuit board 10d in the fifth embodiment of the present invention is different from the circuit board 10 in the first embodiment in that the thicknesses of the conductive lines 11 with different widths are the same to meet the requirement for consistency of circuit thickness in the circuit board 10d.

[0090] Furthermore, the conductive layer 1d also includes a virtual circuit 14, which can improve the heat dissipation effect of the circuit board 10d and can also improve the electromagnetic shielding effect of the circuit board 10d.

[0091] Specifically, the virtual circuit 14 is disposed close to the conductive circuit 11 with a smaller width, and the sum of the width of the conductive circuit 11 with a smaller width and the width of the corresponding virtual circuit 14 is equal to the width of the conductive circuit 11 with a larger width.

[0092] It should be noted that if Figure 7 As shown, when the angle between the two side edges 113 and the upper edge 112 in the cross section of the conductive circuit 11 is 90°, the cross section of the virtual circuit 14 is also rectangular, and the width of the virtual circuit 14 refers to the distance between the two side edges 113 in the cross section of the virtual circuit 14. It can be seen that the cross section of the conductive circuit 11 with a smaller width and the corresponding cross section of the virtual circuit 14 can be spliced ​​along the direction of the plane where the conductive layer 1 is located to form a cross section of the conductive circuit 11 with a larger width. For example, the conductive layer 1 includes a first conductive circuit 114 and a second conductive circuit 115, wherein the width d1 of the first conductive circuit 114 is less than the width d2 of the second conductive circuit 115, then, the virtual circuit 14 is arranged at a position adjacent to the first conductive circuit 114, and the sum of the width d3 of the virtual circuit 14 and the width d1 of the first conductive circuit 114 is equal to the width d2 of the second conductive circuit 115.

[0093] When the angle between at least one of the side edges 113 and the upper edge 112 is greater than 90°, it can be known that the distance between the two side edges 113 gradually increases along the downward direction perpendicular to the conductive layer 1. At this time, the width of the virtual circuit 14 and the width of the conductive circuit 11 are based on the same plane parallel to the upper surface of the conductive layer 1. In this plane, the width of the conductive circuit 11 is the distance between the two side edges 113 in the cross section of the conductive circuit 11 and the two intersections of the plane, and the width of the virtual circuit 14 is the distance between the two side edges 113 in the cross section of the virtual circuit 14 and the two intersections of the plane. At this time, the sum of the width of the conductive circuit 11 with a smaller width and the corresponding width of the virtual circuit 14 is equal to the width of the conductive circuit 11 with a larger width. Specifically, in each plane parallel to the upper surface of the conductive layer 1, the sum of the width of the conductive circuit 11 with a smaller width and the corresponding width of the virtual circuit 14 is equal to the width of the conductive circuit 11 with a larger width.

[0094] In a specific embodiment, a corresponding virtual circuit 14 is provided on one side of the conductive circuit 11 with a smaller width. Of course, this is not limited thereto, and corresponding virtual circuits 14 may be provided on both opposite sides of the conductive circuit 11 with a smaller width, or at least two virtual circuits 14 may be provided on one side, and the sum of the widths of all corresponding virtual circuits 14 is equal to the width of the conductive circuit 11 with a larger width.

[0095] Furthermore, the spacing distance between the dummy circuit 14 and the corresponding conductive circuit 11 is no greater than 2 μm.

[0096] Correspondingly, the difference between the method for preparing the circuit board 10d in the fifth embodiment of the present invention and the method for preparing the circuit board 10 in the first embodiment is that:

[0097] A photocurable adhesive is coated on a carrier 4, and then a polymer 12 having a patterned conductive groove 13 and a patterned virtual groove is formed by photocuring, wherein the carrier 4 at the conductive groove 13 and the virtual groove is exposed outward from the conductive groove 13, that is, the conductive groove 13 and the virtual groove penetrate the photocurable adhesive;

[0098] The conductive groove 13 is filled with copper powder and sintered to form the copper conductive line 11, and the virtual groove is filled with copper powder and sintered to form the virtual line 14, thereby forming a conductive layer.

[0099] The circuit board 10d and the manufacturing method thereof in the fifth embodiment of the present invention are the same as the circuit board 10 and the manufacturing method thereof in the first embodiment except for the above-mentioned differences, and are not described herein in detail.

[0100] Please refer to Figure 8-Figure 9As shown, the present invention also provides a multi-layer circuit board 20, which includes at least two stacked circuit boards 10; there is a connecting hole between two adjacent conductive layers 1, and an electrical connection column 202 located in the connecting hole to electrically connect the two conductive layers 1.

[0101] Specifically, the communicating hole may be a blind hole or a through hole. Figure 8 As shown, in a specific embodiment, the connecting hole is a blind hole. In this case, a blind hole penetrating the conductive layer 1 on the circuit board 10 and an electrical connection column 202 located in the blind hole can be formed on the corresponding circuit board 10 before the circuit board 10 is stacked. Fig. 9 As shown, in another specific embodiment, the connecting hole is a through hole that penetrates the circuit board 10 on which the connecting hole is set. At least two circuit boards 10 can be stacked and connected first, and then the corresponding circuit board 10 is penetrated to form the connecting hole and the electrical connection column 202 located in the connecting hole.

[0102] Furthermore, the present invention also provides a light-emitting module, which includes the above-mentioned circuit board 10 or the above-mentioned multi-layer circuit board 20, a solder resist layer arranged on the exposed conductive layer 1, and LED lamp beads, wherein the solder resist layer exposes the welding part on the upper surface of the conductive layer 1, and the LED lamp beads are soldered to the welding part.

[0103] It can be known that when the light-emitting module includes the multi-layer circuit board 20 , the above-mentioned exposed conductive layer 1 is the conductive layer 1 in the circuit board 10 stacked on the uppermost side.

[0104] Compared with the prior art, the polymer 12 of the conductive layer 1 in the circuit board 10 of the present invention is configured to contain a carboxyl group (—COOH); on the one hand, the oxygen atom in the carboxyl group contains unbonded electrons, which can cooperate with the empty orbitals of the ions on the metal surface to form monodentate, bidentate, or bridged coordination bond adsorption, thereby improving the adhesion between the polymer 12 and the metal. At the same time, a thin oxide film is often easily formed on the metal surface, resulting in poor adhesion of the metal. The carboxyl group is acidic and will react with the metal oxide film or the metal to micro-etch the metal surface, further improving the adhesion between the metal and the polymer 12, that is, it can improve the bonding adhesion between the polymer 12 and the conductive line 11, and improve the yield rate of the circuit board 10.

[0105] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0106] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A circuit board, comprising a conductive layer, wherein the conductive layer has a plurality of conductive lines and a polymer disposed adjacent to at least one conductive line; characterized in that: The polymer contains carboxyl groups.

2. The circuit board according to claim 1, wherein: The carboxyl groups account for 0.1% to 5% of the mass of the polymer.

3. The circuit board according to claim 1, wherein: The polymer further comprises at least one of amino, hydroxyl, methacryloxy functional silane, and gamma-glycidyloxypropyltrimethoxysilane.

4. The circuit board according to claim 3, characterized in that: The amino group accounts for 0.5% to 15% of the mass of the polymer; the hydroxyl group accounts for 0.5% to 5% of the mass of the polymer; the methacryloxy functional silane accounts for 1% to 3% of the mass of the polymer; and the γ-glycidyloxypropyltrimethoxysilane accounts for 1% to 3% of the mass of the polymer.

5. The circuit board according to claim 1, wherein: The polymer is a light-curing adhesive after light curing or a heat-curing adhesive after heat curing.

6. The circuit board according to claim 1, wherein: The conductive circuit is a copper conductive circuit.

7. The circuit board according to claim 1, wherein: The circuit board also includes a substrate layer, and the conductive layer includes a lower surface connected to the substrate layer and an upper surface opposite to the lower surface; the lower edge of the conductive circuit located at the lower surface in the cross section is arc-shaped.

8. The circuit board according to claim 1, wherein: The circuit board also includes a substrate layer, and the conductive layer includes a lower surface connected to the substrate layer and an upper surface opposite to the lower surface; the cross-section of the conductive circuit has an upper edge located at the upper surface, a lower edge located at the lower surface, and a side edge connecting the upper edge and the lower edge at one end on the same side, and at least one of the side edges has an angle greater than 90° with the upper edge.

9. The circuit board according to claim 1, wherein: Conductive circuits with different widths have corresponding thicknesses of different types, and the width of the conductive circuit is inversely proportional to the thickness.

10. The circuit board according to claim 1, wherein: At least two conductive lines have different widths, and the thickness of the conductive line with a larger width is not greater than the thickness of the conductive line with a smaller width.

11. The circuit board according to claim 1, wherein: The circuit board also includes a substrate layer, and the conductive layer includes a lower surface connected to the substrate layer and an upper surface opposite to the lower surface; the lower surface of the conductive circuit has an adhesion promoting layer.

12. The circuit board according to claim 1, wherein: The circuit board further comprises a heat-conducting adhesive layer connected to the lower surface of the conductive layer and a substrate layer connected to the heat-conducting adhesive layer; the heat-conducting adhesive layer comprises: Epoxy resin, wherein the epoxy resin accounts for 20%-75% of the mass of the thermal conductive adhesive layer; Heat dissipation powder, the heat dissipation powder accounts for 5%-50% of the mass of the thermal conductive adhesive layer; Modified propane derivatives and / or γ-glycidyloxypropyltrimethoxysilane, wherein the modified propane derivative accounts for 10%-30% by weight of the thermally conductive adhesive layer, and the γ-glycidyloxypropyltrimethoxysilane accounts for 1%-5% by weight of the thermally conductive adhesive layer; Mercapto derivatives and / or toughened elastomeric resins, wherein the mass of mercapto derivatives accounts for 5%-10% of the thermally conductive adhesive layer, and the mass of toughened elastomeric resin accounts for 5%-20% of the thermally conductive adhesive layer.

13. The circuit board according to claim 12, wherein: The circuit board further includes a heat-conductive insulating layer located between the heat-conductive adhesive layer and the substrate layer.

14. A multi-layer circuit board, characterized in that: The multilayer circuit board comprises at least two stacked circuit boards as claimed in any one of claims 1 to 13; a connecting hole is provided between two adjacent conductive layers, and an electrical connection column is located in the connecting hole to electrically connect the two conductive layers.

15. A light emitting module, characterized in that: The light-emitting module comprises the circuit board according to any one of claims 1 to 13 or the multi-layer circuit board according to claim 14.

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