Fabrication Of Polyimide Research Articles

Humidity-Induced Volume-Expansion of Polyimide Films

Thin polyimide layers were investigated to determine their volume expansion as a result of humidity absorption and desorption, respectively. Furthermore, we used the experiments in order to clarify the physical and chemical processes of polyimide films in wet environment as well as their humido-mechanical properties. It could be shown that the humidity-induced material extension is fairly linear in a wide range of humidity. The observed material behaviour strongly depends on the conditions of the polyimide fabrication process. Analogous to the well-known temperature extension coefficient, a humidity extension value of about 60 to 90 ppm/%RH was observed. This physical effect can be used to create piezoresistive humidity sensors working similarly to bimetal elements influenced by temperature.

Fluorinated polyimide fabrication by magnetically controlled reactive ion etching (MC RIE)

This paper describes the etching rates and morphologies of etched surfaces of fluorinated polyimides having fluorine concentrations, when a magnetic field parallel to the cathode surface was varied during magnetically controlled reactive ion etching (MC RIE). The fluorine concentration of fluorinated polyimides is a key parameter used to control the etching rate in MC RIE and the etching rate can also be increased by applying a high magnetic field. The etching rate was maximum when the fluorine concentration was 15-23 wt%, and the peaks became sharper as the magnetic field increased. The surface morphology also became smoother with increasing magnetic field, and SEM observation revealed that the surface morphology of 23 wt% fluorine polyimide was smoothest when a high etching rate and a high magnetic field were used.

Fabrication of polyimide masks for x-ray lithography

The dimensional stability of a polyimide membrane is a key to the successful fabrication of x-ray masks. It depends upon fractionation, purification, and the degradation prevention of polyamic acid. The polyimide membranes thus obtained have a great tensile stress so that the membrane flatness and distortion in a 30×40 mm rectangular window area are less than 1 μm and 0.2 μm, respectively. The advantages of using a polished glass plate as a substrate are good flatness, low cost, ease of fabrication, and also that the masks’ dimensions can be made large enough at will.