Yasushi Oyama

Title: **Innovative Contributions of Yasushi Oyama in Semiconductor Technology**

Introduction

Yasushi Oyama is an esteemed inventor based in Kodaira, Japan, recognized for his significant contributions to semiconductor technology. With a single patent to his name, Oyama's innovative methods have advanced the field, particularly in the selective deposition processes pivotal for creating effective semiconductor devices.

Latest Patents

Yasushi Oyama's notable patent is titled "Method of Selectively Depositing Tungsten upon a Semiconductor Substrate." This inventive method involves selectively depositing tungsten on a silicon semiconductor substrate. The process starts with coating the silicon substrate with a masking film of PSG or SiO₂, which is then patterned to create openings for the formation of electrodes or wiring.

Specifically, a layer of tungsten approximately 2000 Å thick is deposited using a Chemical Vapor Deposition (CVD) method with a gaseous mixture of WF₆ and H₂. During the deposition, tungsten nuclei also form on the surface of the masking film. The process is strategically halted before these nuclei can form a continuous film. At this point, H₂ gas is introduced into the CVD apparatus to produce HF, which effectively etches the masking film's surface, allowing for the removal of tungsten nuclei. This deposition and removal cycle is repeated until the thickness of tungsten and the masking film is uniform, leading to a flat surface. The final step involves depositing and patterning an aluminum film on this flat surface by lithography, resulting in accurate and reliable wiring, facilitating the production of VLSI with sub-micron dimensions.

Career Highlights

Yasushi Oyama is notably employed at Fujitsu Corporation, where he has played a vital role in developing advanced semiconductor technologies. His innovative techniques not only contribute to enhancing the performance of semiconductor devices but also set a high standard in the industry.

Collaborations

During his professional journey, Yasushi Oyama has collaborated with esteemed colleagues, including Yoshimi Shioya and Norihisa Tsuzuki. Their combined efforts have furthered the research and development of methodologies significant to semiconductor fabrication.

Conclusion

Yasushi Oyama's contributions to semiconductor technology exemplify the spirit of innovation that drives progress in the field. His patent on the selective deposition of tungsten represents a noteworthy advancement, showcasing his expertise and dedication to improving semiconductor processes. As the industry continues to evolve, Oyama's work remains influential, paving the way for future innovations in semiconductor manufacturing.