Nitrogen reflow ovens: the effect exit temperature has on benzotriazole coated copper boards

Reports on the comparisons made of three nitrogen capable ovens. The ovens range in size and price representative of common market offerings. The ovens compared were forced convection type and oxygen concentrations (02 ppm) were set at comparable levels. All of the ovens have some exit cooling capability (nitrogen contained). Cards exiting the oven may be oxidized to different levels, dependent on the card's temperature. The level of oxidation sustained on the card's second side due to the first reflow operation and/or any intermediate process steps, e.g., misprinted paste strips, should be known. Downstream solderability and/or processability operations may be affected. Results from this work were used to provide process engineering a quantifiable way of making capital expense decisions.