Applied Announces TSV Etcher, In-Fab Mask Inspection Capability
Applied Materials Inc. announced its Silvia deep silicon etcher for creation of the smooth sidewalls required for 3-D interconnects. Also, the company said it is offering a new version of its Aera2 mask inspection tool for use within a fab's lithography cell, rather than at an external mask shop, needed for double patterning.
David Lammers, News Editor -- Semiconductor International, 12/1/2008 10:25:00 AM
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Applied said its Centura Silvia etcher enables smooth, vertical via sidewalls that are critical for the subsequent deposition of high-quality liner and fill films. The system can etch both silicon and oxide in the same chamber. Ellie Yieh, general manager of the etch and cleans business unit, said multiple via etch steps represent a large portion of the cost of creating TSV 3-D interconnects.
“We have focused on providing a system that overcomes the traditional etch rate/profile trade-off, while significantly lowering the cost of ownership,” Yieh said. The Silvia system employs Applied’s proprietary time-multiplexed gas modulation (TMGM) process. It builds on Applied’s experience in deep trench silicon etch, where the company has an installed base of >200 chambers.
The company said the system supports both via-first and via-last approaches. For via-first processes, the etcher provides the high photoresist selectivity needed to create small, deep holes with smooth sidewalls. For the via-last steps performed by packaging and semiconductor companies where cost of ownership (CoO) is critical, the Silvia system reduces costs by using low-cost consumables, the company said.
Aera2 for Lithography
With double patterning coming into volume manufacturing, fabs must ensure that critical dimension uniformity (CDU) is maintained on masks after multiple exposures and haze buildup. Applied said that by using the Aera2 system’s IntenCD aerial inspection technology in the fab’s lithography cell, manufacturers can improve wafer CDU by >20%, increase device yields, and lower the per-wafer cost of patterning.
“CD uniformity specifications are very tight at the 45 nm node and below, especially for double patterning, and at least half of the variation in CD comes from the mask,” said Tom St. Dennis, senior vice president of Applied’s Silicon Systems Group.
The IntenCD technology creates CDU maps from the aerial image of the entire reticle. Applied says that by replacing wafer-based measurements with IntenCD maps, the time to decision about the mask’s usability shrinks from two days to as little as an hour. Also, the improved uniformity data makes it possible for scanners to compensate for CD variations, improving linewidth accuracy.
The in-fab inspections will allow fab managers to stretch mask lifetimes, the company said. “Mask properties change dynamically and non-uniformly with cumulative exposures, inducing CD errors from haze defect growth and pellicle degradation,” a press release stated. “By replacing traditional fixed mask reconditioning intervals with predictive scheduling, fab managers can use the Aera2 system to minimize mask reconditioning cycles, increasing mask lifetime and availability.”
The inspection tool can be used with the company’s Tetra reticle clean system, eliminating the need to send masks outside the fab for reconditioning.
