Pulsus Is a Breakthrough for PiezoMEMS Gadgets

Courtesy: Lam Analysis

• The device allows the deposition of high-quality, extremely scandium-doped AlScN movies
• Options embrace dual-chamber configuration, degas, preclean, goal library, exact laser scanning, and extra

On this submit, we clarify how the Pulsus system works, and the way it can obtain superior movie high quality and efficiency in comparison with typical applied sciences.

PiezoMEMS units are microelectromechanical methods that use piezoelectric supplies to transform electrical vitality into mechanical movement, or vice versa. They’ve purposes in a variety of fields, together with sensors, actuators, microphones, audio system, filters, switches, and vitality harvesters.

PiezoMEMS units require high-quality skinny movies of piezoelectric supplies, reminiscent of aluminum scandium nitride (AlScN), to realize optimum efficiency. Typical deposition applied sciences—suppose sputtering or chemical vapor deposition—face challenges in producing AlScN movies with desired properties, reminiscent of composition, thickness, stress, and uniformity. These obstacles restrict each the scalability and performance of piezoMEMS units.

Revolutionary Tech 

To assist overcome these challenges, Lam Analysis lately launched Pulsus, a pulsed laser deposition (PLD) system that we hope will revolutionize the world of piezoMEMS purposes. The addition of Pulsus PLD to the Lam portfolio additional expands our complete vary of deposition, etch and single wafer clear merchandise targeted on specialty applied sciences and demonstrates Lam’s steady innovation on this sector.

Pulsus is a PLD course of module that has been optimized and built-in on Lam’s production-proven 2300 platform. It was developed to allow the deposition of high-quality AlScN movies, that are important to provide piezoMEMS units.

A key good thing about the Pulsus system is its potential to deposit multi-element skinny movies, like extremely scandium-doped AlScN. The intrinsic excessive plasma density—together with pulsed progress—creates the circumstances to stabilize the weather in the identical ratio as they arrive from the goal. This management is important for depositing supplies the place the performance of the movie is pushed by the exact composition of the weather.

Plasma, Lasers 

Native plasma permits for prime native management of movie specs throughout the wafer, like thickness and native in-film stress. Pulsus can alter deposition settings whereas the plasma “hovers” over the wafer floor. This native tuning of thickness and stress permits for prime uniformities over the wafer, which is precisely what our prospects are asking for.  And since the plasma is generated regionally, Pulsus makes use of targets which can be a lot smaller than you’ll sometimes see in PVD methods. Pulsus can alternate these smaller targets, with out breaking vacuum, by way of a goal alternate module—the goal library.

Pulsus makes use of a pulsed high-power laser to ablate a goal materials, on this case AlScN, and create a plasma plume. The plume expands and impinges on a substrate, the place it kinds a skinny movie.

Pulsus has a quick and exact laser optical path which, together with the goal scanning mechanism, permits for uniform and managed ablation of the goal materials. The Pulsus system has a excessive management of plasma plume era, wafer temperature, and strain management to realize the specified movie composition and stoichiometry.

By combining these options, Pulsus can produce high-quality movies with superior efficiency for piezoMEMS units. Pulsus can obtain wonderful composition management, with low variation of the scandium (Sc) content material throughout the wafer and inside particular person units. It additionally delivers excessive movie uniformity, with low WiW (within-wafer) and wafer-to-wafer (WtW) variation of the movie thickness and stress.

Breakthrough Know-how 

Pulsus is a breakthrough expertise for AlScN deposition, which may enhance movie high quality and efficiency for piezoMEMS purposes. As well as, Pulsus has the potential to reinforce the performance and scalability of piezoMEMS units. The Pulsus expertise deposits AlScN movies with very excessive Sc focus, leading to excessive piezoelectric coefficients, which drive greater system sensitivity and output. These movies characteristic tunable stress states to allow the design of various system configurations and shapes.

Pulsus is presently in use on 200 mm wafers and is deliberate to broaden to 300 mm wafers sooner or later—a transfer that has the potential to extend the productiveness and yield of piezoMEMS units.