Experimental and modeling analysis of the reliability of the anisotropic conductive films

Experiments as well as computer modeling methods have been used to investigate the effect of the solder reflow process on the electrical characteristics and reliability of anisotropic conductive film (ACF) interconnections. In the experiments, the contact resistance of the ACF interconnections was found to increase after a subsequent reflow and the magnitude of this increase was strongly correlated to the peak temperature of the reflow profile. In fact, nearly 40 percent of the joints were opened (i.e. lifted away from the pad) after the reflow with a peak temperature of 260 OC while no openings was observed when the peak temperature was 210 "C. It is believed that the CTE mismatch between the polymer particle and the adhesive matrix is the main cause of this contact degradation. To understand this phenomenon better, a 3-D model of an ACF joint structure was built and Finite Element Analysis was used to predict the stress distrihution in the conductive particles, adhesive matrix and metal pads during the reflow process. The effects of the peak temperature, the CTE of the adhesive matrix and the bump height on the reliability of the ACF interconnections were discussed.

Effects of reflow process on the reliability of flip chip on flex interconnections using anisotropic conductive adhesives

In this paper, the effects of the solder reflow process on the reliability of anisotropic conductive film (ACF) interconnections for flip chip on flex (FCOF) applications are investigated. Experiments as well as computer modeling methods have been used. In the experiments, it was found that the contact resistance of ACF joints increased after the subsequent reflow process, and the magnitude of this increase was strongly correlated to the peak temperature of the reflow profile. Nearly 40% of the joints were opened (i.e. lifted away from the pad) after the reflow process with 260 °C peak temperature while no opening was observed when the peak temperature was 210 °C. It is believed that the CTE mismatch between the polymer particle and the adhesive matrix is the main cause of this contact degradation. It was also found that the ACF joints after the reflow process with 210 °C peak temperature showed a high ability to resist water absorption under steady state 85 °C/85%RH conditions, probably because the curing degree of the ACF was improved during the reflow process. To give a good understanding, a 3D model of an ACF joint structure was built and finite element analysis was used to predict the stress distribution in the conductive particles, adhesive matrix and metal pads during the reflow process.

Effects of solder reflow on the reliability of flip-chip on flex interconnections using anisotropic conductive adhesives

This work describes the work of an investigation of the effects of solder reflow process on the reliability of anisotropic conductive film (ACF) interconnection for flip-chip on flex (FCOF) applications. Experiments as well as computer modeling methods have been used. The results show that the contact resistance of ACF interconnections increases after the reflow and the magnitude of the increase is strongly correlated to the peak reflow temperature. In fact, nearly 40 percent of the joints are open when the peak reflow temperature is 260°C, while there is no opening when the peak temperature is 210°C. It is believed that the coefficient of thermal expansion (CTE) mismatch between the polymer particle and the adhesive matrix is the main cause of this contact degradation. To understand this phenomenon better, a three-dimensional (3-D) finite element (FE) model of an ACF joint has been analyzed in order to predict the stress distribution in the conductive particles, adhesive matrix and metal pads during the reflow process. The stress level at the interface between the particle and its surrounding materials is significant and it is the highest at the interface between the particle and the adhesive matrix.

Adult personality inconsistency and problems with parents: uncovering the roots of the false self

Research has established that individuals who tend to vary their personality depending on who they are with, show a variety of signs of psychological maladjustment in comparison to those who do not; they show more negative affect (Baird, Le and Lucas, 2006), lower life satisfaction (Suh, 2002), lower self-esteem (Sheldon et al., 1997), lower role-satisfaction (Donahue et al., 1993), higher rates of depression (Lutz and Ross, 2003), more anxiety (Diehl, Hastings and Stanton, 2001) and poorer physical health (Cross, Gore and Morris, 2003). It has also been shown that personality variability is positively related to the experience of inauthenticity and falsity (Sheldon et al., 1997). Donahue, Roberts, Robins and John (1993) found that personality inconsistency of this type is related to tension within the family. Psychoanalytic theory has also linked the operation of an adult false self to experiences with parents, particularly in early life (Winnicott, 1960). It was hypothesized that personality variability and the adult experience of falsity in social situations would be related to an emotionally unstable relationship with parents. The method to test this comprised a questionnaire-based survey given to a non-clinical population. The final sample comprised 305, with 193 women and 112 men, aged from 19 to 55. The first questionnaire asked participants to rate personality traits, including emotional stability, in three social contexts - with parents, with friends and with work colleagues. The second part involved 3 questions; participants were asked to select in which of the aforementioned three social contexts they felt “most themselves”; in which they were “most authentic” and in which they “put on a front”. It was found, consistent with predictions, that an index of overall personality variability calculated from the personality questionnaire correlated strongly with emotional instability around parents (r = 0.46, p<0.001), while not correlating with emotional instability in either of the other two contexts measured. This suggests a specific link between a person’s relationship with their parents and their overall personality integration. Furthermore, it was found that participants who cited one of the three social contexts (parents, friends, work colleagues) as being one in which they were “more themselves” or “more authentic” had significantly higher ratings of emotional instability with parents than those participants who found that they were equally authentic across settings (F = 9.8, p<0.005). The results suggest a clear link between a person’s relationships with their parents and their adult personality integration. An explanation is that individuals who experience an anxious or ambiguous attachment with their parents in childhood may fear rejection or abandonment in later life, and so habitually adapt their personality to fit in to social contexts as adults, in order to be accepted by others and to minimize the possibility of social rejection. These individuals meanwhile retain an emotionally unstable relationship with their parents in adulthood. This interpretation is speculative but is open to empirical testing. Clinicians should be aware that attachment problems with parents may underlie poor personality integration in adulthood.