Laser Annealing of Cermet Resistors
Original Publication Date: 1985-Dec-01
Included in the Prior Art Database: 2005-Feb-19
A defocussed laser beam is used to anneal the cermet resistors to a specified value below the design value and then trimming the resistor up to the design value using a focussed beam. Both the anneal and the trimming can be done using the same equipment. The resistance value of each of the resistors is continuously monitored both during anneal and trim. ADVANTAGES: 1. Eliminates the need for an expensive annealing step using forming gas. 2. Only the resistors are subject to temperatures of annealing. The conductors and solder pads are not subject to high temperatures. Therefore, problems related to copper oxidation are eliminated. 3. Resistors will be annealed to a specific resistance value.