Abstract: Thermoelectric effects that occur during laser trimming of resistors (20) are resolved by taking voltage measurements. The voltage attributed to laser heating on a resistor (20) during a low-power simulated trim (10) is used to determine a relatively thermal-neutral location (18) on the resistor (20). A trimming-to-value operation can then be performed on all like resistors (20). Voltage measurements can also be taken before and after every pulse in a trimming operation to establish thermal deviation information that can be used to offset the desired trim value against which resistor measurement values are compared. Spatially distant or nonadjacent resistors (20) in a row or column can also be trimmed sequentially to minimize heating effects that might otherwise distort resistance values on adjacent or nearby resistors (20).

Abstract: Thermoelectric effects that occur during laser trimming of resistors (20) are resolved by taking voltage measurements. The voltage attributed to laser heating on a resistor (20) during a low-power simulated trim (10) is used to determine a relatively thermal-neutral location (18) on the resistor (20). A trimming-to-value operation can then be performed on all like resistors (20). Voltage measurements can also be taken before and after every pulse in a trimming operation to establish thermal deviation information that can be used to offset the desired trim value against which resistor measurement values are compared. Spatially distant or nonadjacent resistors (20) in a row or column can also be trimmed sequentially to minimize heating effects that might otherwise distort resistance values on adjacent or nearby resistors (20).

Abstract: High speed removal of material from a specimen employs a beam positioner for directing a laser beam axis along various circular and spiral laser tool patterns. A preferred method of material removal entails causing relative movement between the axis of the beam and the specimen, directing the beam axis at an entry segment acceleration and along an entry trajectory to an entry position within the specimen at which laser beam pulse emissions are initiated, moving the beam axis at a circular perimeter acceleration within the specimen to remove material along a circular segment of the specimen, and setting the entry segment acceleration to less than twice the circular perimeter acceleration.