Resistance adjustment with short-pulse Nd:YAG laser for RuO/sub 2/-based thick-film resistors buries in polyimide film

To adjust the resistance of thick-film resistors (TFRs) buried in polyimide film, a process using a laser is proposed. Short-duration pulses from an Nd:YAG laser are used to irradiate the TFRs through the polyimide film. The TFR surface is modified thermochemically, and the resistance is reduced by an increasing amount with an increasing number of laser pulses. Because a 5-ns laser pulse is too short to start vaporization, no degradation of the polyimide film occurs. Temperature dependences of resistance show that the electrical conduction in the laser-modified TFR differs from that in the original TFR, because of higher electron density. >