Self-repairing integrated circuit based on dispersion particles and preparation method thereof

Abstract

The invention relates to the technical field of integrated circuit chip packaging, in particular to a self-repairing integrated circuit based on dispersion particles and a preparation method thereof.According to the self-repairing integrated circuit based on the dispersion particles, welding spots of the circuit comprise particles of a core-shell structure, and the particles are distributed in the welding spots in a dispersion mode; the core-shell structure is composed of low-melting-point brazing filler metal microspheres and coating metal. The self-repairing brazing filler metal can be subjected to metallurgical reaction with a welding spot material to generate composite brazing filler metal with the melting point higher than that of the self-repairing brazing filler metal; the cladding metal covers the surface of the self-repairing brazing filler metal, and the melting point is higher than that of the self-repairing brazing filler metal; when the welding spots have cracks, the self-repairing brazing filler metal is melted and fills the cracks, and it is ensured that the electrical function of the self-repairing integrated circuit is complete; the design of the core-shell structure particles dispersed in the welding spots is adopted, various welding spot cracks can be dealt with, the preparation method is compatible with a conventional electronic assembly process in the prior art, the cost is low, implementation is convenient, and popularization is easy.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit chip packaging technology, specifically to a self-healing integrated circuit based on dispersed particles and its fabrication method. Background Technology

[0002] In the field of integrated circuit chip packaging technology, solder joint failure is a common problem. The failure process of a solder joint generally follows this pattern: stress and strain lead to deformation—crack initiation in weak areas—crack propagation along the interface—overall cracking and failure. Under the influence of external environmental factors such as thermal cycling, vibration, and impact, approximately periodic stress and strain will be generated within the solder joint, thereby inducing the formation and propagation of cracks, ultimately leading to solder joint failure. Traditional repair techniques for solder joint failure often involve resoldering.

[0003] In the prior art, there are self-repairing methods for the integrated packaging structure of phased array antenna microsystems, such as the one disclosed in CN114050422B. This method replenishes the interconnecting solder joints of the array with liquid metal through a liquid metal self-charging interface, thereby replenishing and repairing the interconnecting solder joints and providing an integrated system with self-repairing capabilities. CN112992833B discloses a conductive element for microelectronic components and the process of forming such a conductive element. This method uses a technical solution where an external soldering material extends onto an internal soldering material bonded to a conductive pad, enabling the conductive element to self-repair after failure.

[0004] However, among the above technical solutions, the former's "replenishing liquid metal" has many difficulties in implementation, while the latter's solution can only be repaired in special cases where the crack happens to pass through its inner welding material, thus having a narrow range of applications.

[0005] Therefore, there is an urgent need for an integrated circuit that can self-heal, cope with various types of solder joint cracks, and is also lower in cost and easier to implement. Summary of the Invention

[0006] In view of this, this application discloses a self-healing integrated circuit based on dispersed particles and its fabrication method to solve the above problems;

[0007] A self-healing integrated circuit based on dispersed particles, wherein the solder joints of the circuit include a core-shell structure of particles dispersedly distributed within the solder joints;

[0008] The core-shell structure is composed of low-melting-point solder microspheres and a coating metal, wherein the low-melting-point solder microspheres are made of self-healing solder.

[0009] The self-healing solder can undergo a metallurgical reaction with the solder joint material to generate a composite solder with a melting point higher than that of the self-healing solder; the composite solder remains solid at the operating temperature of the self-healing integrated circuit.

[0010] The coating metal covers the surface of the self-healing solder and has a melting point higher than that of the self-healing solder.

[0011] When a crack occurs at the solder joint, the self-healing solder melts and fills the crack, ensuring the integrity of the electrical function of the self-healing integrated circuit.

[0012] A method for fabricating self-healing integrated circuits based on dispersed particles, comprising:

[0013] S1. Prepare metal-coated particles on the surface of low-melting-point brazing filler microspheres to obtain core-shell structured particles;

[0014] S2. Preparation of hybrid solders based on core-shell structured particles;

[0015] S3. Using a mixed solder for integrated circuit welding process, a self-healing integrated circuit based on dispersed particles is obtained.

[0016] The self-healing integrated circuit based on dispersed particles designed in this application achieves the self-healing function of solder joints through the design of core-shell structured particles. Furthermore, through the dispersed distribution design, it is ensured that solder joint cracks under various conditions can pass through the core-shell structured particles. The self-healing solder reacts with the solder joint material to generate a composite solder with a higher melting point, thereby solving the problem of solder joint failure and realizing the self-healing of the circuit. It has a wide range of applications.

[0017] This application also provides a method for fabricating self-healing integrated circuits based on dispersed particles. The process is simple, compatible with conventional electronic assembly processes in the prior art, low in cost, easy to implement, and easy to promote. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the solder joints of particles with a core-shell structure in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the core-shell structure of the particles in the embodiments of this application;

[0020] Figure 3 This is a schematic diagram illustrating the propagation of microcracks to particles with a more superficial core-shell structure in an embodiment of this application.

[0021] Figure 4 This is a schematic diagram showing the propagation of microcracks to particles with deeper core-shell structures in an embodiment of this application;

[0022] Figure reference numerals: 1-solder joint, 2-core-shell structured particles, 3-coating metal, 4-low melting point brazing filler metal microspheres. Detailed Implementation

[0023] To make the objectives, technical solutions, features, and advantages of this application clearer and to enable those skilled in the art to better understand the technical solutions of this application, the following detailed description of this application is provided in conjunction with the accompanying drawings and embodiments.

[0024] Example 1:

[0025] This embodiment includes a self-healing integrated circuit based on dispersed particles, wherein the self-healing integrated circuit, such as... Figure 1 As shown, solder joint 1 of the circuit includes a core-shell structure of particles 2, which are dispersedly distributed within solder joint 1; the core-shell structure, as... Figure 2 As shown, it is composed of low-melting-point solder microspheres 4 and a coating metal 3. The low-melting-point solder microspheres 4 are selected from self-healing solder. The self-healing solder can undergo a metallurgical reaction with the solder joint 1 material to generate a composite solder with a melting point higher than that of the self-healing solder. The composite solder remains solid at the operating temperature of the self-healing integrated circuit. The coating metal 3 covers the surface of the self-healing solder and has a melting point higher than that of the self-healing solder. When a crack occurs in the solder joint 1, the self-healing solder melts and fills the crack, ensuring the integrity of the electrical function of the self-healing integrated circuit.

[0026] The self-healing solder is selected from one of the following: In-containing alloy, Bi-containing alloy, and Ag-containing alloy. Solder with compositions such as InSn, SnBi, InBi, InBiSn, and SnAg can be used, with a eutectic composition being preferred. Considering the solder joint 1 and the crack initiation size, the size of the low-melting-point solder microspheres is preferably 10~30μm.

[0027] The coating metal 3 is selected from either a soluble metal material or a diffusion-blocking material; the soluble metal material is soluble in the solder joint 1 material, has a thickness of 1μm~2μm, and is selected from Cu, Ni, Co, and Fe; the diffusion-blocking material is insoluble in the solder joint 1 material, has a thickness of 0.1μm~0.4μm, and is selected from Pt, Cr, Ti, and W.

[0028] In a preferred embodiment, the coating metal 3 in this embodiment is a soluble metal material. The reasons for preferably using a soluble metal material for the coating metal 3 include:

[0029] 1. Soluble metallic materials are more common, have relatively low melting points, and are easy to prepare and process.

[0030] 2. The metal composition is the same as or similar to that of the base material of the solder pad, and will not cause great damage to the performance of the formed solder joint 1. Under the premise of reasonable proportion adjustment, the structural or electrical performance of solder joint 1 can also be improved.

[0031] In this embodiment, the thickness design of the cladding metal 3 satisfies the following: after welding, a cladding layer material with a thickness of 1~2μm exists around the low-melting-point solder. This ensures both physical isolation between the low-melting-point material and the base solder, and also ensures that when cracks propagate at solder joint 1, they can penetrate the cladding layer, allowing the molten low-melting-point solder to overflow and fill and repair microcracks. The existence of a reasonable cladding layer structure can play a role in metallurgy and dispersion strengthening; that is, the dissolved cladding layer material will undergo a metallurgical reaction with the components of the solder base at solder joint 1, generating beneficial intermetallic compounds and enhancing the overall performance of solder joint 1. Soluble metal materials are usually prepared by electroplating or chemical displacement.

[0032] In some other embodiments of this application, if the coating metal 3 is a diffusion barrier material, the diffusion barrier metal material usually has low miscibility with the solder material of the solder joint 1, and less is consumed during the formation of the solder joint 1. Therefore, its thickness should not be too thick, and it is preferable to be able to cover the self-healing solder component. It is usually prepared by electroplating deposition and sputtering.

[0033] Furthermore, such as Figure 4 As shown, when the crack in solder joint 1 initiates and expands, the molten low-melting-point brazing filler metal in the core-shell structure flows into the crack and undergoes chemical metallurgical bonding with the brazing filler metal matrix, thereby closing the crack and preventing its further expansion, which would cause solder joint 1 to fail.

[0034] In some common applications, the core-shell coated self-healing solder is in a solid state so as not to affect the overall functional structure of the solder joint 1. In some special applications, when the coating metal 3 is a diffusion barrier material, that is, when it does not react with the self-healing solder, the low-melting-point solder can remain in a liquid state. When the crack initiates or extends to the core-shell structure and causes it to rupture, the liquid low-melting-point solder flows out and reacts with the solder joint parent solder to generate a high-melting-point mixture and solidify, forming a filling and blocking effect on the microcrack and preventing it from further expanding and causing the solder joint to fail.

[0035] Furthermore, the composite solder generated by the metallurgical reaction between the self-healing solder and the solder joint 1 material remains solid at the operating temperature of the self-healing integrated circuit based on dispersed particles.

[0036] Example 2:

[0037] This embodiment includes a method for fabricating a self-healing integrated circuit based on dispersed particles, comprising:

[0038] S1. Prepare metal coatings on the surface of low-melting-point brazing filler microspheres to obtain core-shell structured particles.

[0039] Specifically, the preparation of the metal coating on the surface of the low-melting-point solder microspheres is achieved through one of the following methods: electroplating, chemical displacement, electroplating deposition, or sputtering. The self-healing solder can be selected from commercially available microsphere products, eliminating the need for custom-made products and thus offering a significant cost advantage.

[0040] S2. Preparation of hybrid solder based on core-shell structured particles.

[0041] Specifically, this includes: mixing core-shell structure particles with solder paste, stirring thoroughly, and then refrigerating to obtain a mixed solder; the proportion of core-shell structure particles is 20 wt%~30 wt%. During the mixing process, flux or thinner is added to adjust the viscosity of the mixed solder to meet the requirements of the printing process. The proportion of core-shell structure particles is set according to the actual situation of the solder joints. Under the premise of optimizing the selection of solder system materials, the amount of added particles should not affect the overall function of the solder.

[0042] In a preferred embodiment, the viscosity of the mixed solder is 600~1200 Pa. s.

[0043] S3. Using a mixed solder for integrated circuit welding process, a self-healing integrated circuit based on dispersed particles is obtained.

[0044] Specifically, depending on the actual situation of the product, conventional electronic assembly processes (such as printing, surface mount technology, reflow soldering, etc.) are used to assemble the product. During the assembly process, the mixed solder melts and solidifies to create solder joints with self-healing capabilities. The above process is compatible with conventional product manufacturing processes.

[0045] When microcracks in the solder joint extend to the core-shell structure particles, the self-healing solder components can melt and flow into the microcrack area at extremely low heating repair temperatures or under conditions requiring no external heat input. This allows them to contact the solder matrix metal and undergo a metallurgical reaction, thus achieving the self-repair function of the brazed joint defects. Because the core-shell structure particles are evenly distributed in the mixed solder through stirring, this solder joint structure can effectively handle solder joint cracks in various situations. Schematic diagrams illustrating microcrack extension to shallower or deeper core-shell structure particles are shown below. Figure 3 , Figure 4 As shown, the design of this application can effectively solve the industry problem of self-repair of microcracks in metal brazing joints.

[0046] Finally, it should be noted that the above description only depicts some embodiments of this application. For those skilled in the art, various changes, modifications, substitutions, and variations can be conceived of these embodiments without departing from the principles and spirit of this application. The scope of protection of this application is defined by the appended claims and their equivalents, and all the above-mentioned behaviors should be covered within the scope of protection of this application.

Claims

1. A self-healing integrated circuit based on dispersed particles, characterized in that, The self-healing integrated circuit has solder joints comprising core-shell structured particles that are dispersedly distributed within the solder joints. The core-shell structure is composed of low-melting-point solder microspheres and a coating metal, wherein the low-melting-point solder microspheres are made of self-healing solder. The self-healing solder can undergo a metallurgical reaction with the solder joint material to generate a composite solder with a melting point higher than that of the self-healing solder; the composite solder remains solid at the operating temperature of the self-healing integrated circuit. The coating metal covers the surface of the self-healing solder and has a melting point higher than that of the self-healing solder. When a crack occurs at the solder joint, the self-healing solder melts and fills the crack, ensuring the integrity of the electrical function of the self-healing integrated circuit.

2. The self-healing integrated circuit based on dispersed particles according to claim 1, characterized in that, The self-healing solder is selected from one of the following: an In-containing alloy, a Bi-containing alloy, or an Ag-containing alloy.

3. The self-healing integrated circuit based on dispersed particles according to claim 1, characterized in that, The low-melting-point brazing filler microspheres have a size of 10~30μm.

4. The self-healing integrated circuit based on dispersed particles according to claim 1, characterized in that, The coating metal is selected from soluble metal materials or diffusion-blocking materials.

5. The self-healing integrated circuit based on dispersed particles according to claim 4, characterized in that, The soluble metallic material is soluble in the solder joint material and has a thickness of 1μm to 2μm; the diffusion-blocking material is insoluble in the solder joint material and has a thickness of 0.1μm to 0.4μm.

6. The self-healing integrated circuit based on dispersed particles according to claim 4, characterized in that, The soluble metal material is selected from Cu, Ni, Co, and Fe, and the diffusion barrier material is selected from Pt, Cr, Ti, and W. When a diffusion barrier material is selected, the self-healing solder can be in liquid state.

7. A method for fabricating a self-healing integrated circuit based on dispersed particles, characterized in that, The method for fabricating a self-healing integrated circuit based on dispersed particles as described in any one of claims 1 to 6 includes: S1. Prepare metal-coated particles on the surface of low-melting-point brazing filler microspheres to obtain core-shell structured particles; S2. Preparation of hybrid solders based on core-shell structured particles; S3. Using a mixed solder for integrated circuit welding process, a self-healing integrated circuit based on dispersed particles is obtained.

8. The method for fabricating a self-healing integrated circuit based on dispersed particles according to claim 7, characterized in that, The preparation of the coated metal on the surface of the low-melting-point brazing filler microspheres is achieved by one of the following methods: electroplating, chemical displacement, electroplating deposition, or sputtering.

9. The method for fabricating a self-healing integrated circuit based on dispersed particles according to claim 7, characterized in that, The preparation of the mixed solder based on core-shell structured particles includes: mixing core-shell structured particles with solder paste, stirring evenly, and then refrigerating to obtain the mixed solder; the proportion of core-shell structured particles is 20Wt%~30Wt.

10. The method for fabricating a self-healing integrated circuit based on dispersed particles according to claim 9, characterized in that, The process involves mixing core-shell structured particles with solder paste, and adding flux or diluent to adjust the viscosity of the mixed solder paste so that the viscosity of the mixed solder paste meets the requirements of the printing process.

Images