Rudolph Technologies, Inc. (NASDAQ: RTEC), a worldwide leader in process characterization solutions for the semiconductor manufacturing industry, announced today that it has recently received 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 followed a six month on-site evaluation, and was based on the unique 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.
“We are, of course, very pleased to win this new business in such an important, leading-edge application,” said Jack Kurdock, vice president and general manager of Rudolph’s Metrology Business Unit. “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 ultra-thin films. Its small spot size permits measurements within die on product wafers which allows for real-time feedback of pre-and post-CMP copper film thickness in the active area, providing an early indication of device performance. This, along with the repeat order received for the Al-based process applications, reaffirms MetaPULSE as the tool-of-record for production monitoring of opaque film thickness.”
The thicknesses of the barrier and seed layers, which are deposited in vias and lines to prevent copper migration and promote uniform nucleation for the subsequent copper fill, are among the smallest and, therefore, most difficult to control dimensions in current device designs. At the 32 nm node, barrier layer (Ta/TaN) thicknesses range from 5 nm to 7.5 nm and seed layer thicknesses from 10 nm to 20 nm. 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. It uses an ultra-fast 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.