According to Korean media TheElec, Samsung is researching and developing new materials for making focus rings. The focus ring is a commodity used in the etch process of wafer fabrication. It holds the wafer in place to maintain plasma density and prevent contamination of the wafer sides.
In the past, quartz and silicon were used to make focus rings. But as the use of dry etches rather than wet etch in advanced wafer fabrication has increased, so has the need for focus rings made of silicon carbide (SiC).
SiC rings are more durable and last longer than pure silicone rings, which helps companies reduce production costs. SiC rings need to be replaced every 15 to 20 days, while silicon rings need to be replaced every 10 to 12 days.
Samsung is now looking for boron carbide (B4C) to replace SiC. The tech giant is currently working with partners with B4C-related technologies to conduct quality tests on the B4C focus ring, the sources said.
B4Cs are harder, which means their units last longer. However, Samsung needs to overcome reliability issues. At the current stage, particles have appeared on the surface of the ring, the source said.
The source also said that Samsung also needs to measure the economic viability of replacing SiC with B4C.