Novellus Systems has introduced SOLA, the industry’s first standalone ultraviolet thermal processing (UVTP) system targeted at the post-deposition processing of advanced dielectric films.
Designed for high-volume manufacturing at 300mm, SOLA reportedly addresses the requirements for new materials and manufacturing technologies necessitated by the next generation of consumer electronic products.
Novellus claims that SOLA is a key enabler for a variety of advanced film applications, including transistor-level high-stress nitrides (HSN) and interconnect-level dense or porous low-k dielectrics.
Using a combination of UV light and heat, SOLA makes post-deposition treatment of these films possible at lower temperatures, a necessity when integrating with new materials such as nickel silicide.
Wafers with a previously deposited plasma-enhanced chemical vapour deposition (PECVD) film are introduced into SOLA, where they are exposed to a uniform UV lamp source to modify the film properties. At the same time, the wafer is heated to a uniform temperature, typically 450 C or less.
With HSN films, SOLA’s UV radiation promotes bond rearrangement and volume contraction to generate the higher stress levels required to enhance device performance. With porous low-k films, UV radiation facilitates removal of porogen, and mechanically strengthens the dielectric film for further processing.
SOLA’s proprietary lamp assembly is said to include dual linear lamps and custom optical reflectors arranged to provide uniform UV light exposure on a 300mm wafer. This arrangement minimises infrared (IR) light that causes undesirable wafer heating and non-homogeneous treatment results. SOLA’s patented multi-station sequential treatment (MSST) architecture results in both high throughput and treatment non-uniformity of less than two percent.
SOLA is also said to be the first UVTP system on the market to offer independent control of UV light intensity, temperature and process time at each treatment station.
“The radiant energy delivered by SOLA can be adjusted to meet the treatment needs of a variety of thin films,” said Tim Archer, senior vice president and general manager of Novellus’ PECVD and Electrofill business units. “While current applications are focused on porous low-k and HSN films, we foresee that there may well be other films that can benefit from the process flexibility afforded by SOLA.”
SOLA also incorporates proprietary purge hardware that minimises clean requirements during wafer processing. More than 100 porogen-containing wafers may be processed in SOLA before a chamber clean is required, a purge efficacy that’s as much as 20 times higher than the industry average.