Automatic Ultrasonic Developing
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
During circuit panel manufacturing a photosensitive emulsion is coated on a screen. The screen is then selectively exposed to ultraviolet light in a predetermined pattern. Exposed emulsion becomes water insoluble, while that not exposed remains water-soluble. Removing the water soluble unexposed emulsion is called developing. This article describes an improved technique for removing water-soluble photoemulsions. Screens are submerged in water at room temperature. The water is first subjected to ultrasonic agitation, then to air agitation. This combination develops the screens consistently with less tension loss than previously experienced using prior-art methods. After the developing step the screens may be dried conventionally.