Title :
A statistical analysis of copper bottom coverage of high-aspect-ratio features using ionized physical vapor deposition
Author :
Snodgrass, T.G. ; Shohet, J.L.
Author_Institution :
Dept. of Electr. & Comput. Eng., Wisconsin Univ., Madison, WI, USA
fDate :
2/1/2002 12:00:00 AM
Abstract :
Ionized physical vapor deposition (IPVD) is a new method for depositing metal into high-aspect-ratio features used as interconnects in microelectronic fabrication. It is similar to sputtering except that a portion of the metal flux to the substrate is ionized. We show how a high ionized-metal-flux fraction (IMFF) at the deposition location improves the bottom coverage of deposited metal films. To measure IMFF, a tool was developed, that biased the front surface of a microbalance crystal directly so as to repel ions. Cu IMFFs to the substrate of greater than 90 % along with deposition rates of 1000 Å/min can be achieved. A statistical model for both IMFF and total metal flux as a function of four control variables, chamber height, Ar pressure, ionizer power, and sputter power, was developed
Keywords :
copper; integrated circuit interconnections; integrated circuit metallisation; ionisation; microbalances; sputter deposition; statistical analysis; Ar; Ar pressure; Cu; Cu IMFFs; IMFF; IPVD; bottom coverage; chamber height; control variables; copper bottom coverage; deposited metal films; deposition location; high-aspect-ratio features; interconnects; ionized PVD; ionized metal flux; ionized physical vapor deposition; ionized-metal-flux fraction; ionizer power; microbalance crystal front surface biasing; microelectronic fabrication; sputter power; sputtering; statistical analysis; statistical model; total metal flux; Chemical vapor deposition; Conductivity; Copper; Filling; Integrated circuit interconnections; Manufacturing; Metallization; Plasma materials processing; Sputtering; Statistical analysis;
Journal_Title :
Semiconductor Manufacturing, IEEE Transactions on
