DYE INDICATORS FOR VISUAL DETECTION OF ORGANIC PROTECTIVE COATINGS ON PRINTED CIRCUIT BOARDS
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2002-Mar-13
A method of detecting organic inhibitor coat- ings (Entek, Protecto, Schercoat) on printed circuit boards was developed to allow visual inspection and identification of defects on incoming boards. Visual detection is accomplished by incorporating select organ& dyes into the organic inhibitor solution prior to coating deposition such that a colored coating is produced. The criteria for dye selection was estab- lished by evaluating various classes of dyes. Solubil- ity in the inhibitor solution and non-reactivity with the metal ions present in the inhibitor solution were found to be critical requirements for dye selection.