Characterization of printing and laser trimming of DuPont 2000 series resistors on DuPont 951 {open_quotes}Green Tape{trademark}{close_quotes}

DuPont 2000 series resistors were reviewed and found to come closest to our requirement of 1% resistor tolerance over the expected 30-year life of our products. The evaluation performed involved the characterization of both the printing and trimming processes. The printing process was characterized for firing temperature print thickness, print direction, resistor geometry and encapsulant effect. Laser trimming was characterized by first finding an operating envelope and then selecting an operating point. The envelope was located by varying the trimming parameters and determining their acceptability to electrical and visual criteria. Samples from both the envelope and operating point were environmentally conditioned The conditioning included thermal shock temperature cycle, 1000-hour temperature aging, 1000-hour humidity aging, and a simulated gold/tin solder reflow