Tunable antenna array for large area microwave plasma source for semiconductor manufacturing

The relentless drive towards semiconductor device miniaturization (e.g., sub-10 nm patterns) and the increasing complexity of 3D stacked structures (e.g., 3D NAND, 3D DRAM, and gate-all-around (GAA) architectures) demand highly efficient radical delivery into deep trenches. This has created a critical need for plasma sources capable of providing high-density radical flux. In response to this trend, Wonik IPS is developing an impedance-matched microwave plasma source. This innovative source features two primary characteristics that enhance its performance and applicability.

First, its design incorporates a Solid-State Power Amplifier (SSPA) for microwave generation and antenna design. Traditional plasma systems typically rely on bulky components like waveguides, magnetrons, and resonant cavities to deliver high-power microwaves to the chamber. While these conventional setups are reliable due to their long history, their significant size is a drawback. SSPA technology addresses this by utilizing semiconductor devices to generate high-power microwaves, drastically reducing the overall volume of the microwave generator. Furthermore, SSPA enables precise digital control over various microwave parameters, including power level, frequency, and phase, offering unparalleled flexibility in plasma control.

Second, the source features an impedance-matched array antenna configuration. By arranging between 4 and 16 microwave plasma generation units within the chamber, this design allows for the generation of microwave plasma in various chamber sizes. Crucially, this array approach optimizes plasma uniformity, a vital parameter for advanced semiconductor manufacturing processes.

To validate the capabilities of this microwave plasma source, we conducted experiments using a mixed gas environment of Argon and Nitrogen. Our results confirmed efficient microwave power transfer to the plasma via N-type connectors and cables. Moreover, the effectiveness of the impedance matching was clearly demonstrated by a significant reduction in reflected power, ensuring optimal power delivery to the plasma.