Report: New wafer-cleaning methods needed for increasingly smaller ICs

04/01/2005

PALO ALTO, Calif.-Rapid advancements in the IC industry, says a report by industry research firm Frost & Sullivan (www.frost.com), are prompting increased demand for new or improved front-end semiconductor manufacturing technologies, such as wafer cleaning and thin-layer deposition.

The report, “World Front-End Semiconductor Manufacturing Technologies,” provides an industry-wide perspective on promising areas of front-end manufacturing, such as etching/wafer wet processing, advanced implantation techniques, and advanced atomic layer deposition (ALD).

“Innovative wafer cleaning technologies, in particular, are crucial to meet the needs for finer fabrication, higher integration densities, and faster speeds of shrinking device features that support greater functionalities,” says Sivakumar Muthuramalingam, research analyst for Frost & Sullivan.

The study also finds that new processes and technology solutions in wafer cleaning have become essential to meet the International Roadmap for Semiconductors (ITRS) requirement for reduced surface contamination in the form of foreign metals, micro-roughness, watermarks, and silicon loss.

Acknowledging the established preference of conventional wet wafer cleaning, due to its robustness and being a risk-free process, the study finds that sub-100-nanometer (nm) devices increasingly will require novel non-etching and damage-free techniques for critical particle removal. Supercritical CO2 (ScCO2) cleaning techniques, the report says, are among those showing the most promise for next-generation yields. ScCO2 uses specialty additives to target specific applications, such as photoresist image collapse prevention, next-generation lithography photomask cleaning, and particle removal.

“Due to its enhanced diffusion properties, such as high density, low viscosity, and negligible surface tension, ScCO2 technology enables the semiconductor industry with an integrated solution for post-etch residue cleaning and the drying of porous low-k materials,” says Muthuramalingam.

In the deposition industry, the report says, advances in separation by implantation of oxygen (SIMOX), ALD for advanced nodes, and plasma source ion implantation (PSII), are expected for meeting the specific needs of sub-100-nm processes. For SIMOX, Frost & Sullivan analysts say, “The relatively immature state of modeling silicon-on-insulator (SOI) devices poses a significant challenge. Researchers are currently developing refined metrology tools to address this issue.”

The report further acknowledges that while there have been significant advances in wafer cleaning and thin-layer deposition, “these techniques must demonstrate tangible advantages over the prevalent competing technologies for quicker acceptance in the market.”

Contents of the report include both wafer-cleaning and thin-layer deposition technology and applications analysis, as well as a global view of innovative methods for each process. Analysis of each technology’s challenges and drivers is also highlighted.

Ordering information is available at the Frost & Sullivan Web site. III