Multilayer anisotropic puncture type conductive fabric adhesive and FPC reinforcing shielding structure using same

Abstract

The invention discloses a multilayer anisotropic puncture type conductive fabric adhesive and an FPC reinforcing shielding structure using the same, wherein the conductive fabric adhesive comprises anupper conductive adhesive layer, a lower conductive adhesive layer and an ultra-thin conductive fabric layer formed between the upper conductive adhesive layer and the lower conductive adhesive layer; the thickness of the upper conductive adhesive layer is 15-25[mu]m, and the thickness of the lower conductive adhesive layer is 35-45[mu]m; the upper and lower conductive adhesive layers comprise metal conductive particles, wherein the metal conductive particles are at least two kinds of a tree branch shape, a chain shape, a needle shape, a slice shape and a sphere shape, and particle sizes of the metal conductive particles are 40-100[mu]m; and the thickness of the ultra-thin conductive fabric layer is 5-15[mu]m. According to the adhesive, the characteristics of an extremely good grounding effect and an electromagnetic shielding effect, high electrical property, excellent bonding strength, excellent tin soldering property, excellent reliability, excellent flame resistance and the like can be achieved by combining with a reinforcing material and an EMI film under the condition that the FPC does not have a reserved grounding hole, and in addition, the production process can be reduced,and the production cost can be lowered.

Description

technical field [0001] The invention belongs to the technical field of conductive cloth for printed circuit boards, in particular to a multi-layer anisotropic puncture type conductive cloth glue and a reinforced shielding structure. Background technique [0002] The development trend of electronic and communication products requires circuit substrate components to develop towards light, thin, small and highly integrated, and the frequency band of transmission signals is getting wider and wider, resulting in more and more serious electromagnetic interference; at the same time, considering the safety of electronic circuit components, the electronic The grounding reliability of circuit components in the product and the degree of freedom of circuit board design have put forward new requirements. At present, the conductive adhesive products commonly used in the market may appear due to the conductive adhesive filling the ground aperture too full, affecting the design and installat...

AI Technical Summary

Problems solved by technology

[0002] The development trend of electronic and communication products requires circuit substrate components to develop towards light, thin, small and highly integrated, and the frequency band of transmission signals is getting wider and wider, resulting in more and more serious electromagnetic interference; at the same time, considering the safety of electronic circuit components, the electronic The grounding reliability of circuit components in the product and the degree of freedom of circuit board design have put forward new requirements. At present, the conductive adhesive products commonly used in the market may appear due to the conductive adhesive filling the ground aperture too full, affecting the design and installation of other components or not filling enough. During reflow soldering, there are gaps in the connection part and there are defects such as explosion boards

[0003] In addition, the FPC reinforced shielding structure in the prior art, such as figure 1 As shown, the steel sheet 200, the FPC 300, the first ground hole 301, the EMI film 400 and the conductive adhesive film 600, the FPC has the first ground hole 301, the first ground hole and part of the FPC are covered with a conductive adhesive film, and the conductive adhesive film After hot pressing, the adhesive layer of the conductive adhesive film melts and flows into the ground hole and conducts with the FPC, which is used for ground shielding. Due to the smaller and smaller requirements for the ground aperture in the current FPC process in the market, the downstream The technical requirements for punching technology are getting higher and higher, but due to the fluidity of the glue itself, the conduction effect of the conductive adhesive material on the extremely small aperture is not ideal, and a new material is urgently needed to improve the extremely small aperture (≤0.5 mm) Grounding effect and stability

At present, there are also some new technologies and patents mentioning that thin metal plating is buried in the conductive adhesive layer to improve the conductivity of conductive adhesive products, reduce the powder content to reduce costs, and it is completely established in theory, but in the actual production process due to the metal itself The flexibility is not good, and the hole filling performance of the product after lamination cannot achieve the expected effect, and it may be even worse. At the same time, the metal plating layer has passed SMT (surface mount technology) in the FPC (printed circuit board) process due to its poor air permeability. Explosion hazard will occur

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