Plasma Surface Modification of Aromatic Liquid Crystal Polymers, and Its Resultant Improvement in Adhesive Strength with Copper Thin Films

Abstract

Surface modification of aromatic LCP surfaces with plasma treatment was carried out to improve the adhesive strength at LCP/Cu interfaces. Plasma treatment to a polymer surface is known to introduce functional groups and to bring about etching action thereon. This study was intended to investigate which or both functional group introduction and etching action contributes to adhesive strength improvement. The effect on the adhesive strength of ordinary plasma treatment and remote plasma treatment was evaluated. Remote plasma treatment is possible to irradiate mainly radicals on LCP surface. The following three subjects were discussed in this study : (1) plasma treatment increases the adhesive strength at LCP/Cu interfaces ; (2) plasma treatment produces oxygen functional groups and nitrogen functional groups and led to etch LCP surfaces, all of which contribute to adhesive strength ; and (3) the oxygen functional groups, nitrogen functional groups, and etching action work simultaneously to enhance adhesive strength by their synergistic effects.

Plasma Surface Modification of Poly(aryl ether ether ketone) and Surface Metallization using Copper Metal

“…Table 1 shows Ra after each plasma treatment. We observed no difference in Ra when using conventional plasma treatment, pulse plasma treatment or In a previous study, the relationship between Ra and weight loss after plasma treatment as well as the adhesive strength of PBN / Cu interfaces was investigated using remote plasma treatment instead of pulse plasma treatment [12]. Their result indicated no difference in other tendencies with respect to Ra, as shown in Table 1.…”

“…Before experiments, the sheets were washed ultrasonically with acetone. The PBN described in our previous report [12] was used for atomic force microscopy (AFM).…”

“…The adhesive strength of interfaces was evaluated using the Ttype peel test. Details of the experimental procedure were given in our previous study [12].…”

“…We have previously investigated the influence of functional group introduction and the etching effect on adhesion with poly (oxybenzoate-co-oxynaphthoate) (PBN). The remote plasma method has previously been used as a plasma technique to irradiate polymers, mainly with radical species, and to introduce functional groups onto polymer surfaces [12]. Our previous study reveals the following three points by comparing the remote plasma method to the conventional plasma method.…”

“…We used the pulse plasma method to irradiate polymers mainly with radical species as described previously [12]. The pulse plasma power was modulated by a cycle of on-time (plasma power is supplied.)…”