Effects of polyimide structure and morphology on adhesion to metals

Semi-flexible polyimides (PI's) such as PMDA-ODA and BPDA-PDA are used in the microelectronics industry as dielectric materials. Generally, the applications of these materials require good adhesion between the circuitization metal (usually Cu) and polyimide (PI). However, the adhesion between Cu and PI is well below the design specifications. This problem can be circumvented by either employing an organic adhesive layer or reactive metals such as Cr. In this study, the physical aspects of PI that lead to poor adhesion properties are examined. Following this, a method is proposed to tailor the structure of PI for adhesion enhancement.