Research status of the hottest conductive adhesive

2022-10-14
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Research status of conductive adhesives

conductive adhesives include two categories, isotropic homogeneous conductive adhesives (ICA) and anisotropic conductive adhesives (ACA). ICA refers to the adhesive that conducts electricity in all directions; ACA is different. For example, z-axis ACA refers to the adhesive that conducts electricity in the Z direction, while it does not conduct electricity in the X and Y directions. Current research focuses on ICA

at present, there are many brands of conductive adhesives on the market, but as far as the matrix is concerned, there are mainly the following categories: epoxy - the matrix material is epoxy resin, and the conductive metal particles filled are mainly: AG, Ni, Cu (plated with Ag); Silicone - its base material is silicone, and the conductive metal particles filled are mainly: AG, Cu (plated with Ag); Polymer - its matrix material is the reason for the mechanical properties of polymer plastics, and the conductive metal particles filled are mainly: AG

advantages of conductive adhesives

in addition to environmental advantages, conductive adhesives also have performance advantages over tin lead solders:

(1) lower curing temperature, which can be applied to thermal sensitive materials and non weldable materials. Do not use SW plug with other electrical and mechanical applications

(2) it can provide finer spacing ability, especially anisotropic conductive adhesive, which can be used at a spacing of only 200 μ M, which has a broad application prospect for the increasingly high-density and miniaturized electronic assembly industry

(3) the process can be simplified (for wave soldering, the process steps can be reduced)

(4) good maintainability. For thermoplastic conductive adhesive, components can be easily replaced after local heating again; For the thermosetting conductive adhesive, it only needs to be locally heated to above Tg to realize the replacement of components. Even if the adhesive is completely cured, you don't have to bother to remove the residue with chemical solvents or sharp tools. You can directly apply the new adhesive and then heat it for curing

limitations of conductive adhesive

although conductive adhesive is a strong competitor of tin lead solder, it also has its own limitations:

(1) low conductivity. For general components, most conductive adhesives can be used, but for power devices, they need to be carefully selected, otherwise the conductivity may not meet the requirements

(2) the bonding effect is greatly affected by the type of components, PCB type, quality and metallization

(3) the curing time is relatively long

(4) if epoxy conductive adhesive is used, attention should be paid to safety. Good bonding performance is the advantage of epoxy conductive adhesive, but once it has a biochemical reaction, it is irritating or toxic, and human skin is prone to allergy to the amine volatilized from it. Therefore, operators must receive safety training

development trend of conductive adhesive

in the future, conductive adhesive as a substitute for tin lead solder, its main power specification: 220V (AC) to make general mechanical parts, wear-resistant parts, transmission parts, such as: and mobile communication system; Radio, television, computer and other industries; Automobile industry; Medical equipment; Solve electromagnetic compatibility (EMC) and other aspects

although conductive adhesives have many advantages, at present, because the theoretical research or production technology is not fully mature, it has formed its own limitations. Therefore, it is still in the trial stage in the high-tech electronic industry. In the future, with the rapid development of electronic assembly industry, the research of conductive adhesives will also enter a higher level, that is, to develop in the direction of high conductivity, low thermal resistance and more reliable. At the same time, we should strengthen the close cooperation between the electronic industry and the material engineering industry, study and formulate the corresponding optimal use process, and make contributions to the early realization of the domestic electronic manufacturing industry into the world's advanced ranks

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