Solder resist composition, solder resist film and printed circuit board

Abstract

This invention relates to a solder resist composition, a solder resist film thereof, and a printed circuit board. The solder resist composition comprises a liquid photosensitive solder resist and a composite magnetic material. The composite magnetic material comprises a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coating the surface of the composite material. In the composite material, multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene cluster, and the zinc sulfide nanomaterials are fused into the graphene cluster. The solder resist film formed by the solder resist composition of this invention has excellent electromagnetic shielding performance. Therefore, after forming the solder resist film on the surface of the printed circuit board, it can effectively shield the signal crosstalk of the printed circuit board itself and interference from other external electronic devices. Moreover, it does not affect the manufacturing process of the printed circuit board. Furthermore, the solder resist film occupies little space, which is beneficial to the trend of miniaturized electronic devices.

Description

Technical Field

[0001] This invention relates to the field of electronic industry technology, and in particular to solder resist compositions, solder resist films and printed circuit boards thereof. Background Technology

[0002] With the rapid development of electronic information technology, high-power, high-speed electronic devices are developing towards high integration and miniaturization, which inevitably leads to electromagnetic radiation interference. Due to the high sensitivity of electronic components to electromagnetic fields, any slight interference may cause electronic components to malfunction in highly integrated electronic devices. If electronic devices without any electromagnetic interference (EMI) shielding are exposed to the electromagnetic fields generated by nearby devices, the electronic devices will easily malfunction.

[0003] Currently, printed circuit boards (PCBs) typically use metal shielding to improve interference immunity. However, metal shielding cannot completely block interference from other external electronic devices. Furthermore, large-area application of metal shielding is costly and requires significant space. If the entire PCB needs shielding, 5mm-10mm of space needs to be reserved around it for the metal shielding, which clearly contradicts the trend towards miniaturized electronic devices. Additionally, crosstalk between high-speed signals on the PCB itself can currently only be addressed through good wiring and component placement to optimize crosstalk between lines, or by adding filtering and protection measures. Summary of the Invention

[0004] Therefore, it is necessary to provide a solder resist composition, its solder resist film, and a printed circuit board in response to the above-mentioned technical problems. The solder resist film formed by the solder resist composition has excellent electromagnetic shielding performance and can effectively shield the signal crosstalk of the printed circuit board itself and the interference from other external electronic devices.

[0005] This invention provides a solder resist composition comprising a liquid photoresist and a composite magnetic material, wherein the composite magnetic material comprises a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coated on the surface of the composite material, wherein in the composite material, a plurality of porous graphene ellipsoids are arranged in an orderly manner to form a graphene cluster, and the zinc sulfide nanomaterials are fused into the graphene cluster.

[0006] In one embodiment, the mass ratio of the liquid photoresist to the composite magnetic material is 5:1 to 8:1.

[0007] In one embodiment, the porous graphene ellipsoids in the graphene group are arranged in a three-dimensional array.

[0008] In one embodiment, the porous graphene ellipsoid has an equatorial radius of 100nm-120nm and a polar radius of 200nm-250nm.

[0009] In one embodiment, the pore size of the porous graphene ellipsoid is 14nm-25nm.

[0010] In one embodiment, the ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous carbon rod is 1:8 to 1:12.

[0011] In one embodiment, the mass ratio of the zinc sulfide nanomaterial to the graphene group in the composite magnetic material is 1:3-1:5.

[0012] The present invention also provides a solder resist film, which is made using the aforementioned solder resist composition.

[0013] The present invention also provides a printed circuit board having the aforementioned solder resist film.

[0014] In one embodiment, the solder resist film is obtained by forming a solder resist composition on a printed circuit board and then curing it.

[0015] This invention, through the selection of materials and the control of the structure in the composite magnetic material, enables the composite magnetic material to achieve an insertion loss of approximately 25 dB in the 20 MHz-1200 MHz frequency band, exhibiting excellent wave absorption performance. Furthermore, the solder resist film formed by the solder resist composition composed of the composite magnetic material and liquid photoresist exhibits excellent electromagnetic shielding performance.

[0016] Therefore, after forming a solder resist film on the surface of a printed circuit board using the solder resist composition of the present invention, it can effectively shield the signal crosstalk of the printed circuit board itself and the interference from other external electronic devices. Moreover, the solder resist film occupies little space and can be used over a large area, which is beneficial to the development trend of miniaturized electronic devices. In addition, the solder resist composition of the present invention is obtained by directly mixing traditional liquid photoresist and composite magnetic materials, which simplifies the manufacturing process. Furthermore, when preparing a solder resist film on the surface of a printed circuit board using the solder resist composition of the present invention, it does not affect the manufacturing process of the printed circuit board, thus having a wide range of applications. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a high-magnification scanning electron microscope image of the graphene group obtained in Example 1;

[0019] Figure 2 This is a high-magnification scanning electron microscope image of the composite magnetic material prepared in Example 1;

[0020] Figure 3 Electromagnetic compatibility (EMC) radiation emissions diagram for a printed circuit board using liquid photoresist;

[0021] Figure 4 Electromagnetic compatibility (EMC) radiation emissions diagram of a printed circuit board using the solder resist composition of Example 1 of the present invention. Detailed Implementation

[0022] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0023] 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 invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0024] The solder resist composition provided by the present invention includes a liquid photoresist solder resist and a composite magnetic material, wherein the composite magnetic material includes a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials and an organic insulating material coated on the surface of the composite material, wherein in the composite material, a plurality of porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, and the zinc sulfide nanomaterials are fused into the graphene group.

[0025] Specifically, the zinc sulfide nanomaterials are integrated into the graphene group in the following ways: zinc sulfide nanomaterials are attached to the surface of at least a portion of the porous graphene ellipsoids, and zinc sulfide nanomaterials are filled in at least a portion of the gaps in the graphene group; furthermore, when the particle size of the zinc sulfide nanomaterials is smaller than the pore size of the porous graphene ellipsoids, the integration of the zinc sulfide nanomaterials into the graphene group also includes the presence of zinc sulfide nanomaterials within the channels of at least a portion of the porous graphene ellipsoids. Of course, the specific integration method will not have a substantial impact on the wave absorption performance.

[0026] Different structural types and materials exhibit varying electromagnetic wave conversion capabilities. In this invention, graphene and zinc sulfide are combined in terms of materials. Structurally, graphene particles are bonded together with binders such as phenolic resin to form porous graphene ellipsoids, which are then arranged in an orderly manner to form graphene clusters. Zinc sulfide nanomaterials are integrated into these graphene clusters in various ways. This allows for faster and more efficient conversion of electromagnetic waves into heat energy. Furthermore, graphene's excellent thermal conductivity enables rapid heat transfer, resulting in an insertion loss of approximately 25 dB for the composite magnetic material in the 20 MHz-1200 MHz frequency band, demonstrating excellent wave absorption performance.

[0027] Meanwhile, the composite magnetic material of this invention uses a graphene cluster composed of multiple porous graphene ellipsoids arranged in an orderly manner as the matrix, and integrates zinc sulfide nanomaterials. It exhibits a dense structure, good toughness, and is not prone to breakage failure under load. Furthermore, the composite material is coated with an organic insulating material, which not only imparts insulation to the composite magnetic material but also makes the bonding of the composite material more stable. Optionally, during the coating process, the organic insulating material can partially coat the surface of the composite material or completely coat the composite material; preferably, the organic insulating material completely coats the composite material. The organic insulating material is preferably a block polymer, such as ethylene oxide and propylene oxide block copolymer ether.

[0028] Furthermore, the solder resist film formed by mixing composite magnetic materials with liquid photoresist exhibits excellent electromagnetic shielding performance. In particular, it demonstrates a more efficient shielding effect against electromagnetic radiation in the 30MHz-1GHz range.

[0029] To further optimize the microwave absorption properties of the solder resist composition, the composite magnetic material can be further optimized.

[0030] For example, in composite magnetic materials, when multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, the porous graphene ellipsoids are arranged in a three-dimensional array; and / or, the equatorial radius of the porous graphene ellipsoids is 100nm-120nm, and the polar radius is 200nm-250nm; and / or, the pore size of the porous graphene ellipsoids is 14nm-25nm, and the ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous graphene ellipsoids is 1:8-1:12.

[0031] Furthermore, the mass ratio of porous graphene ellipsoids to zinc sulfide nanomaterials in the composite magnetic material can be further optimized, as can the mass fraction of the composite magnetic material in the solder resist composition. In one embodiment, the mass ratio of zinc sulfide nanomaterials to graphene groups in the composite magnetic material is 1:3-1:5; in another embodiment, the mass ratio of the liquid photoresist to the composite magnetic material is 5:1-8:1.

[0032] It is understood that the present invention does not limit the selection of the liquid photoresist; any existing liquid photoresist can be used. Common liquid photoresist includes photosensitive epoxy and acrylic resins, such as hydroquinone epoxy resin, phenolic epoxy resin, phenolic epoxy resin, and ethyl carbamate; photoinitiators, such as thioxanthone, benzophenone, carbonyl compounds, chalcone, and organometallic amine compounds; fillers, such as silica powder; curing agents, such as aromatic esters, acid anhydrides, and imidazoles; solvents, such as ether esters; defoamers, etc.

[0033] Based on this, the present invention also provides a solder resist film, which is made of the aforementioned solder resist composition. Thus, the solder resist film has excellent electromagnetic shielding performance, especially for electromagnetic radiation in the range of 30MHz-1GHz, and can be selectively applied to various carriers that require electromagnetic shielding performance.

[0034] In application, the solder resist composition can be coated onto a carrier and dried to form a solder resist film, or the solder resist composition can be coated onto a substrate film and dried to obtain a solder resist film, and then the solder resist film can be pressed onto a carrier.

[0035] It is understood that the solder resist composition of the present invention can be prepared in advance, or the liquid photoresist and composite magnetic material can be stored separately. When applying, the liquid photoresist and composite magnetic material can be mixed and stirred evenly. The manufacturing process is simple. When preparing, an appropriate amount of water can be added.

[0036] Furthermore, the present invention does not limit the preparation method of composite magnetic materials, and any preparation method can be used to obtain them, as long as the structure and materials meet the above conditions of the present invention, the desired effect can be achieved.

[0037] In one embodiment, the preparation method of the composite magnetic material includes the following steps: preparing graphene groups using a colloidal crystal template method, then mixing the graphene groups with zinc sulfide nanomaterials, adding organic insulating materials, heating to a viscous state, and then cooling to obtain the composite magnetic material.

[0038] The specific steps for preparing graphene groups using the colloidal crystal template method include: preparing a first formulation by mixing graphene with water, then mixing the first formulation with a binder to form a second formulation, then adding the second formulation to a colloidal crystal template and heating it under an inert atmosphere, and then cooling it under a reducing atmosphere to obtain the graphene group.

[0039] The graphene to water mass ratio is 1:2-1:4, the graphene to binder mass ratio is 10:1-10:3, the binder is preferably a resin-based binder, such as phenolic resin, the graphene to colloidal crystal mass ratio is 6:1-12:1, the colloidal crystal template is selected from polymethyl methacrylate colloidal crystal template, the heating temperature is preferably 180℃-220℃, the heating time is preferably 20h-28h, the inert atmosphere is selected from nitrogen, argon, etc., and the reducing atmosphere is selected from carbon monoxide, hydrogen, etc.

[0040] To further improve the stability of graphene, a reducing catalyst, such as SnCl2 or FeCl2, can be added to the first formulation. The mass ratio of graphene to the reducing catalyst is 1:1 to 2:1. Then, the mixture is heated in an inert gas and cooled in a reducing atmosphere to obtain a more stable first formulation. The preferred heating temperature is 220℃ to 280℃, and the preferred heating time is 4h to 8h.

[0041] The manufacturing process of printed circuit boards mainly includes copper plating, tin plating, film removal, circuit etching, tin removal, and solder resist. Based on this, the present invention also provides a printed circuit board in which the solder resist process adopts the solder resist composition of the present invention to give the printed circuit board the solder resist film.

[0042] Optionally, the solder resist process includes: using a screen to roll the solder resist composition of the present invention onto a printed circuit board, then pre-baking at a temperature of about 100°C to prevent it from sticking to the film during exposure, followed by exposure treatment, and finally, at a temperature of about 200°C, to completely harden the hardener in the liquid photoresist to form a solder resist film.

[0043] After the solder resist composition of the present invention forms a solder resist film on the surface of a printed circuit board, it can effectively shield the signal crosstalk of the printed circuit board itself and the interference of other external electronic devices. Moreover, the solder resist film occupies little space and can be used over a large area, which is conducive to the development trend of miniaturized electronic devices.

[0044] In addition, the solder resist composition of the present invention is obtained by directly mixing traditional liquid photoresist and composite magnetic materials, which is simple to manufacture. Moreover, when the solder resist composition of the present invention is used to prepare solder resist film on the surface of printed circuit board, it will not affect the manufacturing process of printed circuit board, and has a wide range of applications.

[0045] The following specific examples will further illustrate the solder resist composition, its solder resist film, and the printed circuit board.

[0046] Example 1

[0047] Graphene powder was added to water at a mass ratio of 1:3 and mixed. Then, SnCl2 was added at a mass ratio of 1:1 to the graphene powder. The mixture was placed in an argon atmosphere and heated at 250°C for 6 hours, followed by cooling in a CO atmosphere to obtain the first formulation. The first formulation was then mixed with phenolic resin to obtain the second formulation, wherein the mass ratio of graphene powder to phenolic resin was 10:2.

[0048] The second formulation was added to polymethyl methacrylate colloidal crystals at a mass ratio of graphene to polymethyl methacrylate colloidal crystals of 8:1. The mixture was then placed in an argon atmosphere and heated at 200°C for 24 hours, followed by cooling in a carbon monoxide atmosphere to obtain the desired product. Figure 1 The graphene group shown is composed of porous graphene ellipsoids arranged in a three-dimensional array. The equatorial radius of the porous graphene ellipsoids is 100 nm, the polar radius is 210 nm, and the pore size is 18 nm.

[0049] Graphene groups and zinc sulfide nanomaterials with a particle size of 1.8 nm were added to water, with a mass ratio of graphene groups to zinc sulfide nanomaterials of 4:1. The mixture was stirred and mixed, then ethylene oxide and propylene oxide block copolymer ether were added, and the mixture was placed in an argon atmosphere and heated to 150°C until it reached a viscous state. After cooling, the desired result was obtained. Figure 2 The composite magnetic material shown.

[0050] The composite magnetic material obtained above was dispersed in water to obtain a suspension. Then, commercially available PM-500 liquid photoresist was taken and mixed with the suspension. The mixture was stirred evenly to obtain a resist composition. The mass ratio of liquid photoresist to composite magnetic material in the resist composition was 6:1.

[0051] Example 2

[0052] Example 2 was carried out in accordance with Example 1, except that the mass ratio of graphene group to zinc sulfide nanomaterial was 5:1.

[0053] Example 3

[0054] Example 3 was carried out in accordance with Example 1, except that the mass ratio of graphene group to zinc sulfide nanomaterial was 3:1.

[0055] Example 4

[0056] Example 4 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 180°C for 24 hours. The equatorial radius of the porous carbon rod was 100 nm, the polar radius was 200 nm, and the pore diameter was 14 nm. In addition, the particle size of the zinc sulfide nanomaterial was 1.7 nm.

[0057] Example 5

[0058] Example 5 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 220°C for 22 hours. The equatorial radius of the porous carbon rod was 110 nm, the polar radius was 210 nm, and the pore diameter was 17 nm. In addition, the particle size of the zinc sulfide nanomaterial was 1.7 nm.

[0059] Example 6

[0060] Example 6 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 220°C for 24 hours. The equatorial radius of the porous carbon rod was 120 nm, the polar radius was 220 nm, and the pore diameter was 22 nm. In addition, the particle size of the zinc sulfide nanomaterial was 2 nm.

[0061] Example 7

[0062] Example 7 was carried out in accordance with Example 1, except that the mass ratio of liquid photoresist to composite magnetic material in the solder resist composition was 5:1.

[0063] Example 8

[0064] Example 8 was carried out in accordance with Example 1, except that the mass ratio of liquid photoresist to composite magnetic material in the solder resist composition was 8:1.

[0065] Comparative Example 1

[0066] Comparative Example 1 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 150°C for 24 hours to obtain a three-dimensional arrangement of spherical graphene groups.

[0067] Comparative Example 2

[0068] Comparative Example 2 was carried out in accordance with Example 1, except that the second formulation was added to polymethyl methacrylate colloidal crystals and heated at 190°C for 18 hours to obtain a three-dimensional arrangement of rod-shaped graphene groups.

[0069] Comparative Example 3

[0070] Comparative Example 3 was carried out in accordance with Example 1, except that carbon nanotubes were used instead of graphene to obtain a group of carbon nanotubes arranged in three dimensions of porous carbon nanotube ellipsoids.

[0071] The solder resist compositions obtained in Examples 1-8 and Comparative Examples 1-3 were used to prepare solder resist films using the same process. The microwave absorption properties of the solder resist films obtained in Examples 1-8 and Comparative Examples 1-3 were tested. The test methods are shown below, and the test results are shown in Table 1.

[0072] Absorption performance: Refer to GB / T32596 to test absorption bandwidth and insertion loss.

[0073] Table 1

[0074]

[0075]

[0076] Application Experiment:

[0077] The same copper-clad laminate was provided, and printed circuit boards were manufactured through processes such as copper plating, tin plating, film removal, circuit etching, tin removal and solder resist. The solder resist process used the solder resist composition obtained in Example 1 to obtain Sample 1.

[0078] Blank sample: The solder resist process directly uses commercially available PM-500 liquid photoresist.

[0079] Sample 1 and the blank sample were subjected to far-field EMI measurements in an anechoic chamber at a field depth of 3m. The results are as follows: Figure 3 He Ru Figure 4 As shown, from Figure 3 and Figure 4 It can be seen that the electromagnetic radiation of sample 1 is significantly reduced.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A solder resist composition, characterized in that, The invention includes a liquid photoresist solder resist and a composite magnetic material, wherein the composite magnetic material comprises a composite material composed of porous graphene ellipsoids and zinc sulfide nanomaterials, and an organic insulating material coated on the surface of the composite material. In the composite material, multiple porous graphene ellipsoids are arranged in an orderly manner to form a graphene group, and the zinc sulfide nanomaterials are fused into the graphene group.

2. The solder resist composition according to claim 1, characterized in that, The mass ratio of the liquid photoresist to the composite magnetic material is 5:1 to 8:

1.

3. The solder resist composition according to claim 1 or 2, characterized in that, In the graphene group, the porous graphene ellipsoids are arranged in a three-dimensional array.

4. The solder resist composition according to claim 1 or 2, characterized in that, The porous graphene ellipsoid has an equatorial radius of 100nm-120nm and a polar radius of 200nm-250nm.

5. The solder resist composition according to claim 1 or 2, characterized in that, The porous graphene ellipsoid has a pore size of 14nm-25nm.

6. The solder resist composition according to claim 1 or 2, characterized in that, The ratio of the particle size of the zinc sulfide nanomaterial to the pore size of the porous graphene ellipsoid is 1:8 to 1:

12.

7. The solder resist composition according to claim 1 or 2, characterized in that, In the composite magnetic material, the mass ratio of the zinc sulfide nanomaterial to the graphene group is 1:3-1:

5.

8. A solder resist film, characterized in that, The solder resist film is made from the solder resist composition as described in any one of claims 1-7.

9. A printed circuit board, characterized in that, The printed circuit board has the solder resist film as described in claim 8.

10. The printed circuit board according to claim 9, characterized in that, The solder resist film is obtained by forming a solder resist composition on a printed circuit board and then curing it.

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