ELFR experiment test verifying anomaly of nano-DRAM products in W-plug process

Early-life failure-rate (ELFR) test is a useful gauge to screen out the harmful or latent-defect memory products. In nano-regime, this test is still suitable to be applied on these kinds of memory products. Through this reliability test, some gap-filling quality with W-plug in via or contact structure is not compact well, causing the degradation in electrical characteristics and deteriorating the function operation with Shmoo function tester. Using the failure analysis skill, this failure mode was located and identified.