Search

With the rapid development of technologies on high density assembly and packaging in electronic industry, isotropic conductive adhesive (ICA) has been paid more and more attention as a potential substitute of solder, due to its advantages of low processing temperature, simple processing conditions and good manufacturability. However, the curing time of most traditional ICA is more than half an hour. The process duration of ICA is 2 or 3 times longer than that of solder. Thus, low efficiencies of energy using and product manufacturing has been one of factors which limits widely application of ICA. Generally, the curing speed of ICA depends on types and amount of curing agent as well as curing temperature. In our previous experiments, the effects of curing temperature and amount of curing agent have been investigated. So, the present work attempts to choose a new kind of curing agent to shorten process duration of ICA. By using new curing agent, the curing duration of ICA could be shortened in 5 minutes with a high curing rate compared with the previous version. In addition, the basic performance including bulk resistivity and viscosity are also investigated in this work. Finally, we present some discussions about the further optimization of performance, for example regarding the ways of achieving better electrical conductivity with lower filler content and improvement of viscosity etc.

Isotropic conductive adhesives (ICAs) with lower bonding temperature, higher resolution and environmental friendly have been used extensively in packaging process. In order to improve the electrical and thermal conductive properties of ICAs, two kinds of bimodal high temperature stable ICAs with matrix SHT6 and fillers with composition of macro silver flakes and boron nitride nanoparticles or macro silver flakes and silicon carbide nanoparticles were studied. In these two kinds of adhesives, the silver flakes were 75wt%, and the contents of nanoparticles were 0wt%, 0.5wt%, 1.5wt%, 2.5wt%, 3wt%, 5wt% in weight. All the samples were cured at 150°C for 1 hour. SEM images and EDS results show the nanoparticles disperse randomly in the ICA. The electrical resistivity of these ICAs depends on the contents of silver flakes and is hardly affected by BN nanoparticles and SiC nanoparticles. The thermal conductivity of these ICAs increases firstly with the weight increase of the BN nanoparticles and SiC nanoparticles. And then it decreases when the content of the nanoparticles beyond a certain point.

With the rapid developments of electronic packaging, there is an increasing demand on high performance isotropic conductive adhesives (ICAs). However, the traditional ICAs are brittle, sensitive for crack formation and delamination, which is one of the major drawbacks that limits their use in a wide range of applications. Therefore great efforts have been made to make conductive adhesives more flexible. The present work aims at studying of several chemicals in terms of flexibilizing materials to modify the stiffness modulus of the conductive adhesives. The effect of the flexibilizers has been characterized by different methods, such as Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Thermogravimetric Analysis (TGA), etc. Moreover, the electrical resistance, thermal conductivity and viscosity are also measured in various conditions. Experimental results indicate that one of the flexibilizing materials using flexible ester-linkage is particular of interest as it offers low electrical resistance, high thermal performance and low modulus without decreasing glass transition temperature (Tg) and influencing curing and decomposition conditions.