Technique for treating manufactured thick film resistors

摘要

A technique for treating a thick film resistor subsequent to manufacture to correct its value and at the same time enhance its electrical characteristics, such as its resistance stability. Use is made for this purpose of a generating unit in which a radio-frequency carrier is overmodulated by a sonic signal to produce periodic bursts of radio-frequency energy at a repetition rate determined by the frequency of the signal. Coupled to the unit is an UP probe whose tip when brought into contact with the surface of the resistor and scanned thereacross acts to bring about an increase in its ohmic value. Also coupled to the unit is a DOWN probe from whose tip is projected a corona discharge beam which when directed toward the resistor and scanned thereacross to irradiate the resistor acts to decrease its ohmic value. By first raising the value of the manufactured resistor above the desired target value with the UP probe and then decreasing its value with the DOWN probe until the target value is attained, this treatment serves not only to correct the value of the resistor but also to enhance its electrical characteristics.