Spray coating of photoresist for pattern transfer on high topography surfaces

In this paper, a new method of photoresist coating, direct spray coating, is studied. This method is especially suited to coat high topography surfaces for some special applications in microelectromechanical systems, radio frequency components and packaging. The most suitable photoresist type and coating process are found. The influence of several coating parameters on the thickness and uniformity of the photoresist layer is investigated. A model describing the dependence of the thickness on the major parameters is presented. Very promising results are obtained using spray coating for the fabrication of several three-dimensional structures.