Laser Trimming

Laser trimming is the manufacturing process of using a laser to adjust the operating parameters of an electronic component or circuit by incrementally reducing the amount of component material.

The most common use of laser trimming is to change the resistance of a thick-film or thin-film resistor by burning away a small proportion of the resistive material. This cut, or trim, increases the resistance of the component by narrowing or increasing the current path through the resistive material.

Actively measuring the resistance value of this resistor as the trim is in progress means that this is a very accurate way of determining the final result.

There are two main types of trimming process: Passive and Active. Passive trim is the adjustment of a single component, for example a resistor or capacitor, to a given value. If the trimming alters the whole circuit output such as voltage, frequency or attenuation, then this is called an Active trim. During the trim process the circuit output is monitored continuously, shutting off the laser automatically when the desired output is achieved.