Anisotropic Conductive Adhesive Film Research Articles

Study of short-circuiting between adjacent joints under electric field effects in fine pitch anisotropic conductive adhesive interconnects

Anisotropic conductive adhesive film (ACF) has been extensively used in the liquid crystal display (LCD) industry for decades on chip-on-glass (COG) applications. It offers the advantages in terms of fine-pitch capability and more environment compatibility. One of the very important performance requirements of using ACF in fine pitch interconnection is not to create leakage of electric current between adjacent joints as it may lead to abnormal display segments/pixels of the LCD. In this work, the possibility of short-circuiting between adjacent joints in fine pitch ACF interconnections under the effects of electric field was investigated. Insulation resistance measurements of the selected adjacent joints against electric field strength 1 V/μm for a 24 h testing duration were discussed and analyzed. The results showed a strong dependence of curing degree of the ACFs on the chance of short-circuiting between adjacent joints under field effects.

Development of an anisotropic conductive adhesive film (ACAF) from epoxy resins

AbstractA thermoset type anisotropic conductive adhesive film (ACAF), which electrically connects an ITO glass and a flex circuit both having conducting pattersn of less than 100 μm in pitch, has been developed. In this development, bisphenol A and bisphenol F epoxy resins were tested to formulate an ACAF with easy‐to‐handle tackiness, flexibility, and strenght. A curing agent that gives fast cure and long shelf‐life properties to the epoxy resin was also selected. The tensile stress–strain responses of obtained adhesive films were successfully used for determining the formulation. Good aftercure physical properties (electrical and mechanical) were obtained. Durability against high temperature and high humidity were also tested to confirm long‐term stability of the conduction of this ACAF. © 1995 John Wiley & Sons, Inc.

Thermomechanical Modeling of Direct Chip Interconnection Assembly

Efforts to model thermomechanical aspects of the Direct Chip Interconnection (DCI) assembly process are described. DCI is a method to simultaneously attach and electrically interconnect bare chips to a substrate using Anisotropic Conductive Adhesive Films (ACAF). Emphasis has been placed on describing the numerical procedure used in the analysis. The major components of the analysis include a calibration procedure to “numerically measure” anisotropic properties of the film, a curing model to capture “frozen-in” stresses, a global analysis that considers the overall assembly station but does not resolve details of the interconnection, and a local model, coupled to the global model, that resolves details about the interconnection. Typical results are shown to demonstrate the capabilities of the model.