Characterization of polyamic acid/polyimide films in the nanometric thickness range from spin‐deposited polyamic acid

A dilute polyamic acid solution was spin‐deposited onto gold substrates and XPS analyses were performed after deposition. Evidence of the presence of organic films on the top surface of the substrates was found. A chemical characterization allowed us to identify these organic films as being polyamic acid after a 125°C curing and polyimide after a 240°C curing. From angle‐dependent data we have shown that the gold substrates were coated quasi‐uniformly by ultra‐thin films. This conclusion was confirmed by an Auger analysis. The computed thickness were found in a range of 1.3 to 2.9 nm depending on the sample preparation conditions. Adsorption was supposed to occur just after the deposition. Some possible mechanisms of the interfacial interaction between the polyamic acid and the surface were proposed. A thermally‐activated chain cleavage was supposed to occur at the interface or near the interface.