Rudolph Technologies, Inc., has announced an order for its MetaPULSE-III thin film metrology tool to be used for measuring copper barrier, seed, and pre-and post-CMP fill layers in high-volume production at a major memory fab in Asia.
The selection was based on the ability of the new MetaPULSE-III to measure films on product wafers with high precision and low cost of ownership. This same major Asian memory manufacturer also recently ordered an additional MetaPULSE tool for in-line process control of aluminum films.
Jack Kurdock, vice president and general manager of Rudolph's Metrology Business Unit said, "Copper barrier and seed layers have reached thicknesses that can be very challenging to measure precisely. Using a newly developed technique that simultaneously extracts information from multiple detectors, the MetaPULSE-III demonstrated superior speed and repeatability on these ultrathin films.”
The tool’s small spot size permits measurements within die on product wafers that allows for real-time feedback of pre-and post-CMP copper film thickness in the active area, providing an early indication of device performance.
At the 32nm node, barrier layer (Ta/TaN) thicknesses range from 5nm to 7.5nm and seed layer thicknesses from 10nm to 20nm. The MetaPULSE system provides a gauge-capable metrology solution for these thin barrier/seed layers in addition to in-die measurement of electroplate and post-CMP copper.
The product also uses a high-speed flash of laser light to generate a sound wave that passes through the film stack. When the sound wave encounters a film interface, an echo returns to the surface. The time between sound induction and echo detection provides a direct measurement of film thickness. The technique can measure thickness, density and other film parameters of multilayer stacks non-destructively and without interference from underlying layers.