Conductive Pathway
Structural components used in integrated circuits to provide a permanent, adjustable resistance or to configure internal logic states. A polysilicon link is often modified after the chip is fabricated by using a laser to burn through the material or by applying a high-current pulse. These links are common in analog circuits where precision tuning of voltage references or timing oscillators is required.
Automated Trimming
Laser systems target specific coordinates on the die to ablate the material and increase the circuit resistance. The state of the polysilicon link changes from a low-resistance conductor to a high-resistance open circuit during this process. Because this change is physical and permanent, it provides a stable configuration that does not require a constant power supply to maintain its memory.
Measured Tolerance
Resistance values must fall within a narrow range to ensure the final circuit meets its design specifications.
Protection Layer
Passivation must remain intact after the trimming process to prevent moisture from entering the device. Degradation of the polysilicon link can occur if the laser energy is not precisely controlled, leading to micro-cracks in the surrounding insulation. Long-term reliability is verified through high-temperature bake tests that simulate years of continuous operation in the field.
