Precise circuit board and manufacturing method thereof

Abstract

The invention discloses a precise circuit board and a manufacturing method thereof, and relates to the technical field of electronic additive manufacturing. The method comprises the following steps: forming a photosensitive activatable catalyst layer on an insulating substrate; forming a light-transmitting and positive photoresist layer on the catalyst layer; performing integrated exposure treatment on the photoresist layer and the catalytic layer under the photoresist layer based on the target circuit pattern; developing the photoresist layer to form a groove which exposes the activation part of the catalyst layer; and performing plating treatment based on the activation part of the catalyst layer to obtain a groove beam type conductive circuit. The photosensitive composite structure is formed by the photosensitive activatable catalyst layer and the transparent and positive photoresist layer on the photosensitive activatable catalyst layer, so that selective activation of the catalyst layer and selective degradation of the photoresist layer can be completed in synchronous exposure treatment of the photosensitive activatable catalyst layer and the transparent and positive photoresist layer, and then the beam type groove can be obtained by developing the photoresist layer. And finally, a groove bundle type conductive circuit can be obtained through plating, so that the yield and the quality of the circuit board are effectively improved.

Description

Technical Field

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

[0002] At present, in order to meet the precision requirements of industrial circuit boards, many manufacturers are more likely to use UV photosensitive layer exposure and development processing methods to form wiring grooves consistent with the target wiring pattern, and then transfer and horizontally cover the wiring grooves with low-temperature conductive paste to form a printed wiring layer with a wiring groove bundle shape. Then, a plated wiring layer is formed on the printed wiring layer in the wiring grooves through electroplating or chemical plating. Finally, the photosensitive layer is removed through a film stripping process to obtain a double-layer wiring structure with a printed wiring layer as the bottom layer and a plated wiring layer as the top layer.

[0003] In the above process structure, although a laterally precise circuit board can be obtained by the bundle shape of the wiring grooves, solving the problem of shortened line spacing and even line short circuit caused by the side growth of the printed wiring layer during the electroplating or chemical plating process, it is still limited by the plating performance of the low-temperature conductive paste, resulting in poor yield and quality. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method for manufacturing a precision circuit board to solve the problem of poor yield and quality of circuit boards in the prior art.

[0005] In some illustrative embodiments, the method for manufacturing the precision circuit board includes: step one, providing an insulating substrate; step two, forming a photosensitive and activatable catalytic layer on the insulating substrate; step three, forming a light-transmitting and positive photoresist layer on the catalytic layer; step four, performing an integrated exposure treatment on the photoresist layer and the catalytic layer thereunder based on a target circuit pattern, and forming a degradation portion and an activation portion consistent with the target circuit pattern on the photoresist layer and the catalytic layer, respectively; step five, performing a development treatment on the photoresist layer, removing the degradation portion on the photoresist layer, so as to form a groove exposing the activation portion of the catalytic layer; step six, performing a plating treatment based on the activation portion of the catalytic layer, to obtain a conductive circuit formed by the groove.

[0006] In some optional embodiments, after obtaining the conductive circuit formed by the grooves, the method further includes: removing the remaining photoresist layer.

[0007] In some optional embodiments, after removing the remaining photoresist layer, the method further includes: removing the unactivated catalytic layer.

[0008] In some optional embodiments, before forming the photosensitive activatable catalytic layer on the insulating substrate, the method further includes: forming a modified primer on the insulating substrate to enhance the adhesion of the catalytic layer on the insulating substrate.

[0009] In some optional embodiments, the plating treatment is performed on the activated portion of the catalytic layer to obtain a conductive circuit consisting of the groove bundle type, including: performing a chemical plating treatment on the activated portion of the catalytic layer to obtain a conductive circuit consisting of the groove bundle type.

[0010] In some optional embodiments, the plating treatment is performed on the activated portion of the catalytic layer to obtain a conductive circuit consisting of the groove bundle type, including: performing a chemical plating treatment on the activated portion of the catalytic layer to obtain a first conductive circuit consisting of the groove bundle type; wherein the thickness of the first conductive circuit is less than the depth of the groove; and performing an electroplating treatment on the first conductive circuit to obtain a second conductive circuit attached to the first conductive circuit.

[0011] In some optional embodiments, a thickness of the second conductive line does not exceed a depth of the groove.

[0012] In some optional embodiments, the insulating substrate is a flexible or hard substrate.

[0013] Another object of the present invention is to provide a precision circuit board obtained by implementing the method for manufacturing a precision circuit board as described in any one of the above.

[0014] In some optional embodiments, the precision circuit board is a single-sided board, a double-sided board or a multi-layer board.

[0015] Compared with the prior art, this application has the following advantages:

[0016] The present application utilizes a photosensitive and activatable catalyst layer and a transparent and positive photoresist layer thereon to form a photosensitive laminate, so that the two can simultaneously complete the selective activation of the catalyst layer and the selective degradation of the photoresist layer in a single exposure process, and then the beam-shaped grooves and the activated portion exposed in the beam-shaped grooves can be obtained by developing the photoresist layer. Finally, the conductive circuit formed by the beam-shaped grooves can be obtained by plating, which not only ensures the precision of the circuit board, but also effectively improves the yield and quality of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an example of a process for manufacturing a precision circuit board in an embodiment of the present invention;

[0018] Figure 2 This is a process example of a method for manufacturing a precision circuit board in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0020] It should be noted that the various technical features in the embodiments of the present invention can be combined with each other without conflict.

[0021] The present invention discloses a method for manufacturing a precision circuit board. Figure 1-2 As shown, Figure 1 This is an example of a process for manufacturing a precision circuit board in an embodiment of the present invention; Figure 2 This is a process example of a method for manufacturing a precision circuit board in an embodiment of the present invention; the manufacturing method comprises:

[0022] Step S11, providing an insulating substrate;

[0023] Step S12, forming a photosensitive activatable catalytic layer on the insulating substrate;

[0024] Step S13, forming a light-transmitting and positive photoresist layer on the catalyst layer;

[0025] Step S14, performing an integrated exposure process on the photoresist layer and the catalyst layer thereunder based on the target circuit pattern, and forming a degradation portion and an activation portion consistent with the target circuit pattern on the photoresist layer and the catalyst layer respectively;

[0026] Step S15, developing the photoresist layer to remove the degraded portion on the photoresist layer to form a groove exposing the activated portion of the catalyst layer;

[0027] Step S16: performing plating treatment based on the activated part of the catalyst layer to obtain a conductive circuit with grooves.

[0028] The present application utilizes a photosensitive and activatable catalyst layer and a transparent and positive photoresist layer thereon to form a photosensitive laminate, so that the two can simultaneously complete the selective activation of the catalyst layer and the selective degradation of the photoresist layer in a single exposure process, and then the beam-shaped grooves and the activated portion exposed in the beam-shaped grooves can be obtained by developing the photoresist layer. Finally, the conductive circuit formed by the beam-shaped grooves can be obtained by plating, which not only ensures the precision of the circuit board, but also effectively improves the yield and quality of the circuit board.

[0029] The insulating substrate in the embodiment of the present invention may include: a flexible substrate, a hard substrate, a soft-hard combination substrate, etc., preferably a sheet or a film, etc.; wherein, the hard substrate may be a traditional PCB board, such as a glass fiber board, a semi-glass fiber board, specifically FR-4, CEM-1, 22F, CEM-3, etc.; in some embodiments, in addition to the traditional PCB board, wood, glass, plastic, PMMA (Acrylic), etc. may also be used; the flexible substrate may include a flexible stretchable substrate and a flexible non-stretchable substrate, such as PET, PVC, PU, ​​PC, PP, PA, PI, CPI (transparent PI), TPE film, etc. In addition to the above substrates, PDMS, silica gel, fabrics (such as non-woven fabrics, nylon, washed cotton, polyester, spandex and woven fabrics blended with various materials, etc.), adhesive films (not limited to TPU, TPV), etc. may also be used. It should be understood by those skilled in the art that in addition to the above substrates, the substrate in the embodiment of the present invention may also be other substrates in the prior art that can satisfy the formation of conductive structures thereon.

[0030] In some embodiments, the insulating substrate in the embodiments of the present invention is suitable for PI or PI improved substrates to create flexible FPC electronics, and can even meet the needs of PET or PET improved substrates, which are substrates with lower temperature resistance, thereby increasing the selection range of the substrate and reducing the production cost of printed circuit boards.

[0031] The photosensitive activatable catalytic layer in the embodiment of the present invention is formed by a photosensitive activatable catalyst, the components of which are as follows: 1-6 parts of a palladium source, 2-8 parts of a dispersant, 1-6 parts of a photoinitiator, 10-30 parts of a resin, 10-30 parts of a multifunctional acrylic monomer, 0.01-0.5 parts of a leveling agent, and the balance is a solvent; or, 0.5-3 parts of a palladium source, 2-8 parts of a dispersant, 0.5-3 parts of a photoinitiator, 0.1-2 parts of a surfactant, 10-15 parts of a solvent, and the balance is deionized water. During UV exposure, the catalyst is excited by free radicals excited by the photoinitiator to convert Pd 2+ Reduction to palladium Pd 0 .

[0032] Preferably, the palladium source used in the embodiment of the present invention is palladium acetate, palladium chloride or palladium sulfate, and the dispersant is a polyester-type hyperdispersant Solsperse-46000 or a polyolefin-type hyperdispersant PVPK30.

[0033] Preferably, the dispersant used plays the role of a stabilizer and disperser after the palladium metal particles are nucleated, and its content ratio also affects the morphology of the metal particles after reduction. The dispersant selected in the present invention is conducive to obtaining spherical palladium metal nanoparticles, increasing the specific surface area of ​​the catalyst and ensuring efficient catalytic properties.

[0034] Preferably, the solvent used is one or a mixture of ethyl lactate, acetone, propylene glycol methyl ether acetate, propylene glycol methyl ether acetate, butyl acetate, and acetylacetone.

[0035] Preferably, the photoinitiator is a cleavage-type free radical photoinitiator: acetophenone compounds (DEAP), acylphosphine oxide (TEPO), α-amino ketone derivatives (2959). The photoinitiator used generates free radicals under ultraviolet light and is a key component in the system formula. It controls the nature and quantity of free radicals generated by light excitation and determines the nucleation and growth process of metal particles. The photoinitiator selected in the present invention is a type 1 cleavage-type photoinitiator, which has high initiation efficiency, a high proportion of palladium metal particles obtained by reduction, and has high catalytic properties.

[0036] Preferably, the multifunctional acrylic monomers used include but are not limited to alkoxylated bisphenol A di(methacrylate), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), tri(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol tetraacrylate (PETTA), trimethylolpropane tetraacrylate (DTMPTA), dipentaerythritol pentaacrylate (DPPA), and dipentaerythritol hexaacrylate (DPHA). The selected monomers have good copolymerizability under the action of free radicals, and have good plasticity, will not hinder the expansion effect, and provide support for the growth of palladium nanoparticles, so as to obtain a nanocomposite material with more uniform catalyst distribution and better dispersibility.

[0037] Preferably, the leveling agent used is a polyether-modified silicone surfactant, an acrylic leveling agent or a fluorocarbon leveling agent.

[0038] Preferably, the resin material used includes aromatic acid acrylic acid oligomers, polyester acrylic acid oligomers, epoxy acrylic acid oligomers, silicone modified acrylic acid oligomers, polyurethane acrylic acid oligomers, etc. The selected resin material is also acrylic acid, and the preferred polyurethane acrylic acid oligomer has good plasticity, which is conducive to the dispersion of free radicals and more conducive to the reduction of palladium nanoparticles in the system.

[0039] In some embodiments, the photosensitivity-activatable catalyst in the embodiments of the present invention may be copper salt, silver salt, gold salt, nickel salt, etc. in addition to palladium salt.

[0040] In some embodiments, after obtaining the conductive circuit formed by the grooves, the method further includes: removing the remaining photoresist layer. This embodiment is used when the circuit board does not need the photoresist layer. In other embodiments, the photoresist layer can also be used as the structure of the circuit board and does not need to be removed.

[0041] In some embodiments, after removing the remaining photoresist layer, the process further includes: removing the unactivated catalytic layer. This embodiment is used when the circuit board does not need a catalytic layer. In other embodiments, since the catalytic layer itself does not have a conductive property, it will not affect the circuit board and therefore does not need to be removed.

[0042] In some embodiments, before forming the photosensitive activatable catalytic layer on the insulating substrate, the method further includes: forming a modified primer on the insulating substrate to enhance the adhesion of the catalytic layer on the insulating substrate.

[0043] Preferably, the primer includes 5-10wt% of polyester polyol; the primer also includes a composite resin; the mass ratio of the composite resin to the polyester polyol is (15-30): (5-10); the composite resin includes a polyurethane resin and an epoxy resin in a mass ratio of (10-20): (5-10). The primer can effectively improve the adhesion of the catalyst layer on the insulating substrate.

[0044] The plating treatment in the embodiment of the present invention is not limited to the chemical plating process or the combination of chemical plating and electroplating process, such as directly growing a conductive circuit of target thickness through the chemical plating process, or first growing an electroplating seed layer (i.e., the first conductive circuit) through the chemical plating process, and then growing a conductive circuit of target thickness (i.e., the second conductive circuit) through the electroplating process.

[0045] In some embodiments, a plating treatment is performed based on the activated portion of the catalytic layer to obtain a conductive circuit with a groove bundle shape, including: a chemical plating treatment is performed based on the activated portion of the catalytic layer to obtain a conductive circuit with a groove bundle shape.

[0046] In some embodiments, a plating treatment is performed based on the activated portion of the catalytic layer to obtain a conductive circuit with a groove bundle shape, including: a chemical plating treatment is performed based on the activated portion of the catalytic layer to obtain a first conductive circuit with a groove bundle shape; wherein the thickness of the first conductive circuit is less than the depth of the groove; and an electroplating treatment is performed based on the first conductive circuit to obtain a second conductive circuit attached to the first conductive circuit.

[0047] In some embodiments, the thickness of the second conductive trace does not exceed the depth of the groove.

[0048] The present invention discloses a method for manufacturing a precision circuit board, comprising:

[0049] S21, providing an insulating substrate;

[0050] S22, forming a modified primer on the insulating substrate;

[0051] S23, forming a photosensitive activatable catalytic layer on the modified primer;

[0052] S24, forming a light-transmitting and positive photoresist layer on the catalyst layer;

[0053] S25, performing an integrated exposure process on the photoresist layer and the catalyst layer thereunder based on the target circuit pattern, and forming a degradation portion and an activation portion consistent with the target circuit pattern on the photoresist layer and the catalyst layer respectively;

[0054] S26, developing the photoresist layer to remove the degraded portion on the photoresist layer to form a groove exposing the activated portion of the catalyst layer;

[0055] S27, performing chemical plating on the activated portion of the catalyst layer to obtain a first conductive circuit with a groove shape; wherein the thickness of the first conductive circuit is less than the depth of the groove;

[0056] S28, performing electroplating on the first conductive circuit to obtain a second conductive circuit attached to the first conductive circuit; wherein the thickness of the second conductive circuit does not exceed the depth of the groove;

[0057] S29, removing the remaining photoresist layer;

[0058] S30, removing the inactivated catalyst layer.

[0059] Another object of the present invention is to provide a precision circuit board, which is obtained by implementing any of the above-mentioned methods for manufacturing a precision circuit board. In some optional embodiments, the precision circuit board is a single-sided board, a double-sided board or a multi-layer board. Among them, the double-sided board, i.e., both sides of the insulating substrate, are manufactured using the above-mentioned process, and a laminate of a catalytic layer and a photoresist layer is formed on both sides, and after exposure respectively, the subsequent processes on both sides can be carried out simultaneously, i.e., simultaneous development, simultaneous plating, etc.

[0060] The double-sided board in the embodiment of the present invention may also be one side of the insulating substrate that uses the above process to form a conductive circuit, while the other side of the insulating substrate uses other processes to form a conductive circuit.

[0061] The multilayer board in the embodiment of the present invention can be formed by stacking and combining the single-sided board and / or the double-sided board in the embodiment of the present invention, or by additionally stacking and combining the single-sided board or the double-sided board.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a precision circuit board, characterized in that: include: Step 1: providing an insulating substrate; Step 2: forming a photosensitive activatable catalytic layer on the insulating substrate; Step 3, forming a light-transmitting and positive photoresist layer on the catalyst layer; Step 4: performing an integrated exposure process on the photoresist layer and the catalyst layer thereunder based on the target circuit pattern, and forming a degradation portion and an activation portion consistent with the target circuit pattern on the photoresist layer and the catalyst layer respectively; Step 5, developing the photoresist layer to remove the degraded portion of the photoresist layer to form a groove exposing the activated portion of the catalyst layer; Step six: performing plating treatment on the activated part of the catalytic layer to obtain a conductive circuit formed by the grooves.

2. The manufacturing method according to claim 1, characterized in that: After obtaining the conductive circuit formed by the grooves, the method further includes: removing the remaining photoresist layer.

3. The manufacturing method according to claim 2, characterized in that: After removing the remaining photoresist layer, the method further includes: removing the unactivated catalytic layer.

4. The manufacturing method according to claim 1, characterized in that: Before forming the photosensitive activatable catalytic layer on the insulating substrate, the method further comprises: A modified primer is formed on the insulating substrate to enhance the adhesion of the catalytic layer on the insulating substrate.

5. The manufacturing method according to claim 1, characterized in that: The method of plating the activated part of the catalyst layer to obtain a conductive circuit formed by the grooves comprises: A chemical plating treatment is performed based on the activated part of the catalyst layer to obtain a conductive circuit formed by the grooves.

6. The manufacturing method according to claim 1, characterized in that: The method of plating the activated part of the catalyst layer to obtain a conductive circuit formed by the grooves comprises: Performing chemical plating on the activated portion of the catalytic layer to obtain a first conductive circuit formed by the grooves; wherein the thickness of the first conductive circuit is less than the depth of the grooves; Electroplating is performed based on the first conductive circuit to obtain a second conductive circuit attached to the first conductive circuit.

7. The manufacturing method according to claim 6, characterized in that: The thickness of the second conductive circuit does not exceed the depth of the groove.

8. The manufacturing method according to claim 1, characterized in that: The insulating substrate is a flexible or hard substrate.

9. A precision circuit board, characterized in that: It is obtained by implementing the method for manufacturing a precision circuit board as described in any one of claims 1-8.

10. The precision circuit board according to claim 9, characterized in that: The precision circuit board is a single-sided board, a double-sided board or a multi-layer board.

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