Failure rate and yield-limiting tungsten plug corrosion diagnosis using characterization test vehicles
- Resource Type
- Conference
- Authors
- Xing Tao; Reis, K.; Haby, B.; Karnett, M.; White, N.; Watts, C.; Delgado, M.; Gardner, K.; Harris, K.R.
- Source
- 13th Annual IEEE/SEMI Advanced Semiconductor Manufacturing Conference. Advancing the Science and Technology of Semiconductor Manufacturing. ASMC 2002 (Cat. No.02CH37259) Advanced semiconductor manufacturing Advanced Semiconductor Manufacturing 2002 IEEE/SEMI Conference and Workshop. :144-149 2002
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Tungsten
Plugs
Corrosion
Testing
Vehicles
Failure analysis
Voltage
Contacts
Qualifications
Etching
- Language
Electrical microprobe and Passive Voltage Contrast (PVC) techniques were used to investigate incompletely filled contacts and vias on our 0.20 um FEOL (Front-End-Of-Line) characterization and process qualification vehicles. The failure mechanism of unfilled tungsten plugs was attributed to electrochemical corrosion during the post-metal etch solvent strip. This tungsten plug corrosion led to high contact and via failure rates, failure of the yield impact prediction model, electromigration test failure, and 3% to 6% yield loss at final test. Several detailed experiments were performed towards identifying and resolving this corrosion plug failure mechanism. It was found that modification of the Tungsten CMP buff significantly reduced the failure rate and led to increased probe yield with improved manufacturability.