Samsung was researching and developing a new material to use to make focus rings, TheElec has learned.
Focus rings are commodities used in the etching process of wafer fabrication. It fixes the wafer in place to maintain the plasma density and prevents the sides of the wafer from contamination.
In the past, quartz and silicon were used to make focus rings. But as the use of dry etching over wet etching increased for advanced wafer fabrications, demand for focus rings made out of silicon carbide (SiC) also increased.
SiC rings are more durable than purely silicon ones and last longer, which helps companies to reduce costs in production. A SiC ring is swapped every 15 to 20 days while a silicon ring is replaced every ten to 12 days.
Samsung is now looking at boron carbide (B4C) to replace SiC. The tech giant was currently collaborating with a partner that has technologies associated with B4C for quality testing of B4C focus rings, sources said.
Like SiC, B4C is durable against high temperatures and plasma. B4C is also harder, which means they can be used longer per unit.
Samsung will however need to overcome reliability issues. In the current phase, there were particles that appeared on the ring’s surface, the sources said.
The company will also need to measure the economic feasibility of replacing SiC with B4C, they said.
SK Hynix had also considered replacing SiC with B4C and conducted relevant research, the sources said.
But the company had put the project on hold due to the expected cost of the replacement.
