WO2023206939A1 - Electronic structure and manufacturing method therefor - Google Patents

Abstract

The present application relates to the technical field of electronic manufacturing. Disclosed are an electronic structure and a manufacturing method therefor. The manufacturing method for an electronic structure comprises: providing a substrate; using a first low-temperature conductive slurry to form a first conductive layer on the substrate, and performing surface drying treatment on the first conductive layer; using a second low-temperature conductive slurry to form on the first conductive layer a second conductive layer which at least covers a target area, and thus obtaining a pad electrode; and performing thermosetting treatment on the first conductive layer and the second conductive layer at the same time, so as to obtain an electronic structure in which the first conductive layer and the second conductive layer are cross-linked and fused into a whole. In the present application, a first conductive layer in direct contact with a substrate is formed by using a first low-temperature conductive slurry having low-conductivity particles and high resin, and a pad electrode is formed on the first conductive layer by using a second low-temperature conductive slurry having high-conductivity particles and low resin. In addition, the first conductive layer and the second conductive layer are subjected to thermosetting at the same time, such that the high-adhesion and weldability effects of an electronic structure are achieved.

Description

An electronic structure and its production method

This application claims priority to the Chinese patent application submitted to the China Patent Office on April 29, 2022, with the application number 2022104740565 and the application title "An electronic structure and its production method", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application belongs to the field of electronic manufacturing technology, and in particular relates to an electronic structure and a manufacturing method thereof.

Background technique

As an emerging additive manufacturing raw material for electronic circuits, conductive paste is often used to form the electronic structures required by users through printing and other methods. Compared with traditional copper foil and aluminum foil etching technologies, the printed conductive paste process is low-cost and cost-effective. Pollution-free, fast, high-volume manufacturing advantages.

According to the sintering and curing temperature, conductive pastes are generally divided into high-temperature conductive pastes and low-temperature conductive pastes. In high-temperature conductive pastes, the glass powder is mainly used as a binder for conductive particles. The sintering temperature generally needs to reach thousands of degrees. , even if expensive low-melting point glass powder on the market is used, its sintering temperature needs to be at least 500°C, which requires high energy consumption, high equipment and supporting costs, and poor versatility, which cannot meet the needs of substrates with poor temperature resistance.

Low-temperature conductive paste mainly uses resin as a binder for conductive particles. The curing temperature generally only needs to be between 100°C and 300°C. It has low energy consumption, low equipment and supporting costs, and can meet the use of most substrates. Conventional low-temperature conductive paste, such as low-temperature conductive silver paste, is mainly a viscous blend formed by mechanical mixing of silver powder, resin (also known as binder), solvent and additives. During the molding and solidification process, In the process, its solvents and additives will gradually evaporate, forming conductive traces composed of silver powder and resin film-forming materials.

At present, the existing low-temperature conductive silver paste is difficult to meet the user requirements for high adhesion and weldability. Especially when molded on glass substrates, the adhesion is poor and it is easy to peel off.

Application content

In view of this, one purpose of this application is to propose a method of manufacturing an electronic structure to solve the problem in the prior art that low-temperature conductive silver paste cannot meet the user requirements of high adhesion and solderability at the same time.

In some illustrative embodiments, the manufacturing method of the electronic structure includes: providing a substrate; providing a first low-temperature conductive slurry that at least contains a resin carrier and conductive particles, and using the first low-temperature conductive slurry Form a first conductive layer on the base material, and perform surface drying treatment on the first conductive layer; wherein, the first conductive layer has at least one target area for forming a pad electrode; and provide at least one A second low-temperature conductive slurry containing a resin carrier and conductive particles is used to form a second conductive layer on the first conductive layer that at least covers the target area to obtain the welding Disk electrode; perform thermosetting treatment on the first conductive layer and the second conductive layer at the same time to obtain an electronic structure in which the first conductive layer and the second conductive layer are cross-linked and fused together; wherein, the The mass fraction of the resin carrier in the first low-temperature conductive slurry is higher than the mass fraction of the resin carrier in the second low-temperature conductive slurry, and the mass fraction of the conductive particles in the first low-temperature conductive slurry is lower than the mass fraction of the resin carrier in the first low-temperature conductive slurry. The mass fraction of conductive particles in the second low-temperature conductive slurry.

In some optional embodiments, in terms of mass fraction, the first low-temperature conductive slurry includes: 55% to 65% of conductive particles, 13% to 18% of resin carrier, 0% to 0.5% of additives, and the rest as solvent.

In some optional embodiments, in terms of mass fraction, the second low-temperature conductive slurry includes: 75% to 85% of conductive particles, 7% to 10% of resin carrier, 0% to 0.5% of additives, and the rest as solvent.

In some optional embodiments, after obtaining the electronic structure cross-linked and integrated by the first conductive layer and the second conductive layer, the method further includes: providing a component; and soldering the component to the on the welding electrode.

In some optional embodiments, soldering the component to the electronic structure specifically includes: printing solder paste at the position of the pad electrode, and using reflow soldering to realize the connection between the component and the electronic structure. Welding between pad electrodes.

In some optional embodiments, the base material is selected from one or more composites of PET, PI, PTFE, PC, ABS, LCP, PU, TPU, FR4, paper, wood, glass, stone, and fabric. base material.

In some optional embodiments, the conductive particles are selected from one or more of gold, silver, copper, aluminum, zinc, nickel, and silver-coated copper.

In some optional embodiments, the resin carrier is selected from polyester resin, polyurethane resin, epoxy resin, acrylic resin, phenolic resin, alkyd resin, silicone resin, chlorine-vinyl resin, and polyimide resin. one or more.

In some optional embodiments, the second conductive layer is consistent with the pattern of the first conductive layer and completely covers the first conductive layer.

Another object of the present application is to propose an electronic structure to solve the technical problems in the prior art.

In some illustrative embodiments, the electronic structure is obtained using any one of the methods for fabricating an electronic structure described above.

Compared with the existing technology, this application has the following advantages:

In the embodiments of the present application, a first low-temperature conductive slurry with low conductive particles and high resin is used to form a first conductive layer that is in direct contact with the base material, thereby ensuring the adhesion of the first conductive layer on the base material. The second low-temperature conductive slurry of the resin forms a pad electrode on the first conductive layer to achieve the tinning performance of the pad electrode, thereby meeting the solderability requirements; in addition, the second conductive layer is formed after the first conductive layer dries. The two are thermally cured at the same time, so that the two form an integrated structure due to the cross-linking reaction, ensuring the bonding strength of the second conductive layer on the first conductive layer, and achieving high adhesion and weldability effects as a whole.

Description of the drawings

Figure 1 is a flow chart of a manufacturing method of an electronic structure in an embodiment of the present application;

Figure 2 is a schematic diagram of the manufacturing process of the electronic structure in the embodiment of the present application;

Figure 3 is a structural example 1 of the electronic structure in the embodiment of the present application;

Figure 4 is a flow chart of a method for manufacturing a transparent display screen in an embodiment of the present application.

Detailed ways

Reference will now be made in detail to various embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. When described in conjunction with these embodiments, it should be understood that the embodiments are not intended to limit the disclosure to these embodiments. On the contrary, the disclosure is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the disclosure as defined by the appended claims. Additionally, in the following detailed description of the disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it is understood that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present disclosure.

It should be noted that the technical features in the embodiments of the present application can be combined with each other as long as there is no conflict.

The embodiment of the present application discloses a method of manufacturing an electronic structure. Specifically, as shown in Figures 1-3, Figure 1 is a flow chart of the method of producing an electronic structure in the embodiment of the present application; Figure 2 is a diagram of the implementation of the present application. A schematic diagram of the manufacturing process of the electronic structure in the example; Figure 3 is a structure example 1 of the electronic structure in the embodiment of the present application; the manufacturing method of the electronic structure includes:

Step S11, provide a substrate 10;

Step S12: Provide a first low-temperature conductive slurry that at least contains a resin carrier and conductive particles, use the first low-temperature conductive slurry to form a first conductive layer 20 on the base material, and apply the first conductive layer 20 to the base material. The conductive layer 20 is surface dried;

Wherein, the first conductive layer 20 has at least one target area for forming a pad electrode;

Step S13: Provide a second low-temperature conductive slurry that at least contains a resin carrier and conductive particles, and use the second low-temperature conductive slurry to form a second layer on the first conductive layer 20 that at least covers the target area. Conductive layer 30 to obtain the pad electrode;

Step S14: Perform thermosetting treatment on the first conductive layer 20 and the second conductive layer 30 at the same time to obtain an electronic structure 40 in which the first conductive layer and the second conductive layer are cross-linked and integrated;

Wherein, the mass fraction of the resin carrier in the first low-temperature conductive slurry is higher than the mass fraction of the resin carrier in the second low-temperature conductive slurry, and the mass fraction of the conductive particles in the first low-temperature conductive slurry is Lower than the mass fraction of conductive particles in the second low-temperature conductive slurry.

In the embodiments of the present application, a first low-temperature conductive slurry with low conductive particles and high resin is used to form a first conductive layer that is in direct contact with the base material, thereby ensuring the adhesion of the first conductive layer on the base material. The second low-temperature conductive slurry of the resin forms a pad electrode on the first conductive layer to achieve the tinning performance of the pad electrode, thereby meeting the solderability requirements; in addition, the second conductive layer is formed after the first conductive layer dries. The two are thermally cured at the same time, so that the two form an integrated structure due to the cross-linking reaction, ensuring the bonding strength of the second conductive layer on the first conductive layer, and achieving high adhesion and weldability effects as a whole.

The base material in the embodiment of this application is selected from one or more composite base materials among PI, PTFE, PC, LCP, FR4, wood, glass, stone, and fabric.

The first low-temperature conductive slurry and the second low-temperature conductive slurry in the embodiments of the present application are at least composed of a resin carrier and conductive particles. In some embodiments, they may also include solvents and/or additives. On the other hand, the first low-temperature conductive slurry and the second low-temperature conductive slurry in the embodiments of the present application are low-temperature conductive slurries, which mainly rely on resin carriers as adhesives, rather than being used in high-temperature environments. Glass powder, and when the role of the glass powder is not used as an adhesive (that is, the melting temperature of the glass powder has not been reached), the low-temperature conductive slurry may also contain glass powder.

Preferably, in order to ensure that the first conductive layer has good conductivity, the mass fraction of the conductive particles of the first low-temperature conductive slurry in the embodiment of the present application needs to be no less than 55%, and in order to improve the first low-temperature conductive slurry For adhesion, the mass fraction of the resin carrier must be no less than 13%, thereby ensuring both the conductivity and adhesion of the first conductive layer.

Those skilled in the art will understand that the mass fraction of the conductive particles in the first low-temperature conductive slurry can be appropriately reduced without considering or having low requirements on the conductive performance of the first conductive layer.

Further, the embodiments of this application propose a low-temperature conductive slurry, which is suitable for use as the first low-temperature conductive slurry in the embodiments of this application. In terms of mass fraction, the low-temperature conductive slurry includes: conductive particles 55 % ~ 65%, resin carrier 13% ~ 18%, additives 0% ~ 0.5%, and the rest is solvent.

The conductive particles in this embodiment can be metal conductive particles, which are not limited to gold, silver, copper, aluminum, zinc, nickel, silver-coated copper, gallium, indium, tin, bismuth, gallium-based alloys, indium-based alloys, and bismuth-based alloys. , tin-based alloy and other metal conductive particles.

Preferably, the conductive particles in the embodiments of the present application can be gold powder, silver powder, and silver-coated copper powder. Compared with copper, aluminum, zinc, nickel, gallium, indium, tin, bismuth, gallium-based alloys, indium-based alloys, and bismuth-based alloys, For base alloys and tin-based alloys, these conductive particles have relatively stable properties under the micron size structure, are not easy to form oxides, and have good conductivity; among them, the conductive particles can be selected from spherical, rod-shaped, flake-shaped, and branch-shaped. Or several.

Preferably, the conductive particles in the low-temperature conductive slurry may have a sheet structure. The conductive particles in this embodiment use a flake structure. The conductive particles with a flake structure have a wider overlapping area, so the conductive slurry of the conductive particles has better conductivity, and under the same conductivity, the conductivity is The demand for particles is lower, so more resin carriers can be mixed in while ensuring conductive properties, thereby improving the adhesion of the conductive slurry.

The size of the conductive particles in this embodiment may range from 2 μm to 10 μm.

The resin carrier in this embodiment can be one or more of polyester resin, polyurethane resin, epoxy resin, acrylic resin, phenolic resin, alkyd resin, silicone resin, chlorine-acetyl resin, and polyimide resin. . Among them, the applicant found that the adhesion of the low-temperature conductive paste to the substrate mainly depends on the type of resin. When the substrate is a glass substrate, preferably, the low-temperature conductive paste can use epoxy resin as the resin carrier. , which can greatly improve the adhesion of low-temperature conductive paste on the glass substrate.

The auxiliaries and solvents in this embodiment are conventional selections in the art and will not be described again.

Specifically, the mass fraction of conductive particles in the low-temperature conductive slurry may be 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64% or 65%. The mass fraction of the resin carrier in the low-temperature conductive slurry may be 13%, 14%, 15%, 16%, 17% or 18%. The mass fraction of the additive in the low-temperature conductive slurry can be 0, 0.1%, 0.2%, 0.3%, 0.4% or 0.5%.

Preferably, in order to ensure that the second conductive layer has good tin application performance, the mass fraction of the conductive particles of the second low-temperature conductive slurry in the embodiment of the present application needs to be no less than 75%. In order to ensure that the second low-temperature conductive slurry has In order to ensure the printability of the second conductive layer, the mass fraction of the resin carrier must be no less than 7%, thus ensuring the printability and solderability of the second conductive layer.

Furthermore, the embodiments of this application propose a low-temperature conductive slurry, which is suitable for use as the second low-temperature conductive slurry in the embodiments of this application. In terms of mass fraction, the low-temperature conductive slurry includes: conductive particles 75 % ~ 85%, resin carrier 7% ~ 10%, additives 0% ~ 0.5%, and the rest is solvent.

The conductive particles in this embodiment can be metal conductive particles, which are not limited to gold, silver, copper, aluminum, zinc, nickel, silver-coated copper, gallium, indium, tin, bismuth, gallium-based alloys, indium-based alloys, and bismuth-based alloys. , tin-based alloy and other metal conductive particles.

Preferably, the conductive particles in the embodiments of the present application can be gold powder, silver powder, and silver-coated copper powder. Compared with copper, aluminum, zinc, nickel, gallium, indium, tin, bismuth, gallium-based alloys, indium-based alloys, and bismuth-based alloys, For base alloys and tin-based alloys, these conductive particles have relatively stable properties under the micron size structure, are not easy to form oxides, and have good conductivity; among them, the conductive particles can be selected from spherical, rod-shaped, flake-shaped, and branch-shaped. Or several.

Preferably, the conductive particles in the low-temperature conductive slurry may have a spherical structure. The conductive particles in this embodiment adopt a spherical structure. The conductive particles with a spherical structure have a larger specific surface area, so the conductive slurry of the conductive particles has more area to react with tin, making it easier to form an alloy;

In addition, the smaller the particle size, the lower the melting point of the conductive particles, which can further enhance the reaction with tin. Specifically, the size range of conductive particles is no more than 2 μm, but if the size is too small, the manufacturing cost of conductive particles will be higher. Therefore, when the size range of conductive particles is selected from 0.5 μm to 2 μm, the cost and tin application performance will be more cost-effective. .

The resin carrier in this embodiment can be one or more of polyester resin, polyurethane resin, epoxy resin, acrylic resin, phenolic resin, alkyd resin, silicone resin, chlorine-acetyl resin, and polyimide resin. . Preferably, polyester resin can be used as the resin carrier in this embodiment, taking into account both heat resistance and electrical conductivity.

The auxiliaries and solvents in this embodiment are conventional selections in the art and will not be described again.

Specifically, the mass fraction of conductive particles in the low-temperature conductive slurry may be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%. The mass fraction of the resin carrier in the low-temperature conductive slurry may be 7%, 8%, 9% or 10%. The mass fraction of the additive in the low-temperature conductive slurry can be 0, 0.1%, 0.2%, 0.3%, 0.4% or 0.5%.

Preferably, the mass fraction of conductive particles in the low-temperature conductive slurry can be 80% to 85%, thereby further improving the tin application performance of the low-temperature conductive slurry. In this embodiment, the mass fraction of the conductive particles can be 80% to 85%. During the tin application process, there is sufficient contact area between the conductive particles and the solder paste, and the solder paste is not easily separated from the conductive particles.

Preferably, the first low-temperature conductive paste in the embodiment of the present application uses an epoxy resin system, and the second low-temperature conductive paste uses a polyester resin system, so that the electronic structure formed by the combination of the two has good performance on the glass substrate. Excellent adhesion, temperature resistance, electrical conductivity and tin application properties.

Optionally, after obtaining the electronic structure cross-linked and integrated by the first conductive layer and the second conductive layer, the method further includes: providing a component; and welding the component to the welding electrode. The components in this embodiment are not limited to chips, LEDs, diodes, transistors, resistors, capacitors, inductors, wires and other components.

Preferably, soldering the component to the electronic structure specifically includes: printing solder paste at the position of the pad electrode, and using reflow soldering to realize the connection between the component and the pad electrode. welding.

Optionally, the second conductive layer in the embodiment of the present application has the same pattern as the first conductive layer and completely covers the first conductive layer. The second conductive layer in this embodiment not only constitutes a welding electrode, but also enhances the overall conductivity and overall weldability of the first conductive layer.

The embodiments of the present application also disclose an electronic structure, which can be obtained by any of the above-mentioned electronic structure manufacturing methods. This electronic structure can be used in electronic circuits such as PCB, FPC, smart wear, transparent display and other fields.

The embodiment of the present application discloses a method for making a transparent display screen, which includes:

Step S21, provide a glass substrate;

Step S22: Use the first low-temperature conductive paste to print the first conductive layer on the glass substrate;

Step S23: Perform surface drying treatment on the first conductive layer;

Step S24: Use the second low-temperature conductive paste to print the second conductive layer on the first conductive layer;

Step S25: Perform thermosetting treatment on the first conductive layer and the second conductive layer at the same time to obtain an electronic structure in which the first conductive layer and the second conductive layer are cross-linked and integrated;

Step S26: Print solder paste on the pad electrode of the obtained electronic structure;

Step S27: Mount the LED lamp beads and perform reflow soldering to obtain a transparent display screen.

The transparent display screen specifically includes: a glass substrate, an electronic structure of an integrated structure formed by cross-linking of a first conductive layer and a second conductive layer printed and formed in succession, and LED lamp beads mounted and welded on the electronic structure.

In addition, other transparent substrates can also be used as the glass substrate in this embodiment to meet the production requirements of film screens and soft film screens.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. scope.

Claims (10)

1. A method for making an electronic structure, which is characterized by including:

   Provide a base material;

   Provide a first low-temperature conductive slurry that at least contains a resin carrier and conductive particles, use the first low-temperature conductive slurry to form a first conductive layer on the substrate, and surface the first conductive layer. Dry processing; wherein, the first conductive layer has at least one target area for forming a pad electrode;

   Provide a second low-temperature conductive slurry that at least contains a resin carrier and conductive particles, and use the second low-temperature conductive slurry to form a second conductive layer on the first conductive layer that at least covers the target area, to obtain The pad electrode;

   Simultaneously perform thermosetting treatment on the first conductive layer and the second conductive layer to obtain an electronic structure in which the first conductive layer and the second conductive layer are cross-linked and integrated;

   Wherein, the mass fraction of the resin carrier in the first low-temperature conductive slurry is higher than the mass fraction of the resin carrier in the second low-temperature conductive slurry, and the mass fraction of the conductive particles in the first low-temperature conductive slurry is Lower than the mass fraction of conductive particles in the second low-temperature conductive slurry.
2. The method of making an electronic structure according to claim 1, characterized in that, in terms of mass fraction, the first low-temperature conductive slurry includes: 55% to 65% of conductive particles, 13% to 18% of resin carrier, and auxiliary materials. Agent 0% ~ 0.5%, the rest is solvent.
3. The manufacturing method of an electronic structure according to claim 1, characterized in that, in terms of mass fraction, the second low-temperature conductive slurry includes: 75% to 85% of conductive particles, 7% to 10% of resin carrier, and auxiliary materials. Agent 0% ~ 0.5%, the rest is solvent.
4. The manufacturing method of an electronic structure according to claim 1, characterized in that, after obtaining the electronic structure cross-linked and integrated by the first conductive layer and the second conductive layer, it further includes:

   provide a component;

   The element is welded to the welding electrode.
5. The method of manufacturing an electronic structure according to claim 4, wherein said soldering the component to the electronic structure specifically includes:

   Solder paste is printed at the position of the pad electrode, and reflow soldering is used to achieve soldering between the component and the pad electrode.
6. The method of manufacturing an electronic structure according to claim 1, wherein the substrate is selected from one or more composite substrates selected from the group consisting of PI, PTFE, PC, LCP, FR4, wood, glass, stone and fabric.
7. The method of making an electronic structure according to claim 1, wherein the conductive particles are selected from gold, silver, copper, aluminum, zinc, nickel, silver-coated copper, gallium, indium, tin, bismuth, and gallium-based alloys. One or more of indium-based alloy, bismuth-based alloy, and tin-based alloy.
8. The manufacturing method of an electronic structure according to claim 1, characterized in that the resin carrier is selected from polyester resin, polyurethane resin, epoxy resin, acrylic resin, phenolic resin, alkyd resin, silicone resin, chlorine-acetic resin , one or more polyimide resins.
9. The method of manufacturing an electronic structure according to claim 1, wherein the second conductive layer has the same pattern as the first conductive layer and completely covers the first conductive layer.
10. An electronic structure, characterized in that it is obtained by the manufacturing method of the electronic structure according to any one of claims 1-9.

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