Reliability Test Results for Pt FIB Interconnect Structures

Abstract

The reliability of FIB deposited Pt structures is assessed through lifetesting of product die and through stress testing of via-intensive test structures. Data is also presented for Pt resistance monitors collected over a 21 month period aimed at assessing the stability of the FIB deposition process. Two product types were subjected to HTOL and HTSS conditions at 125°C followed by temperature cycling. The test structures were stressed at different combinations of temperature ranging from 100°C to 140°C and with currents up to 5 mA. Neither product type experienced any FIB related failures whereas the test structure saw 70% fallout due to degradation of the Pt material within the vias. Temperature cycling did not precipitate any failures. The Pt resistance monitor data showed that film resistance increases with film thickness indicating the incorporation of organic byproducts from the deposition process.