The area of spread solderability test use for roughness influence assessment

The article deals with the influence of surface roughness on solderability. The area of spread test was used as a method for solderability measurement. For this measurement, test samples made from substrates for printed circuit boards, small solder balls, and two soldering technologies – vapor-phase and reflow soldering - were used. These technologies have been used because of similarity with the industrial process of soldering. The subjects of examination and comparison were wetting angle and expanse of melted solder on the surface. The paper presents results and conclusions from solderability testing of printed circuit boards with various surface roughnesses. Other conclusion is comparison of several types of fluxes and their impact on solder wetting on roughened surface.