What is a quartz focus ring?

             
        A quartz focus ring is a critical consumable component in semiconductor plasma etching processes. It is typically made of high-purity fused quartz and plays an indispensable role in chip manufacturing. Its core function is to confine and guide plasma to ensure highly uniform etching performance across the wafer surface.

 

Core Functions:
Why is it indispensable to etching processes?

        During plasma etching, quartz focus rings primarily perform the following key tasks:

• Focusing plasma for uniform etching: Through purpose-built design, it keeps plasma stable and uniform even at the wafer edge. By optimizing the electric field around the wafer periphery, it eliminates the "edge effect" and ensures highly consistent etch rates and critical dimensions (CD) across the entire wafer surface.
   
• Protecting high-value equipment and extending component service life: The focus ring acts as a consumable protective shield that bears direct plasma bombardment, shielding underlying core precision components such as the electrostatic chuck (ESC) from damage.
   
• Preventing contamination and safeguarding wafer yield: Quartz itself contains no harmful impurities such as metals, and releases oxygen slowly under plasma exposure. This oxygen reacts with polymers generated during etching to form easily pumpable gases like CO and CO₂, effectively preventing contamination on the wafer backside.

       
        Jingge Semiconductor – Custom processing of high-purity quartz devices (5N, 6N purity), including synthetic quartz, gas-fused quartz, electrically fused quartz, quartz components, quartz etch rings, quartz focus rings, quartz wafers, optical quartz sheets, etc. Tel: 17826693981.

Why Quartz? Analysis of Material Advantages

      Multiple material options exist for focus rings, but quartz stands out for its unique combination of properties:

• Ultra-high purity: Semiconductor-grade quartz typically reaches a purity of 99.998% or above, minimizing metal impurity contamination to wafers – the foundation for reliable chip yield.
• Superior chemical corrosion resistance: Quartz withstands erosion by highly corrosive etching gases (such as CF₄, SF₆ and Cl₂) and plasma attack.
• Excellent thermal stability: Quartz can endure temperatures over 1000°C and has an extremely low coefficient of thermal expansion, ensuring precise dimensional stability throughout high-temperature processes.
• Favorable dielectric properties: Its dielectric constant (around 3.8) supports the desired plasma focusing performance.

Manufacturing & Market:
Precision Machining and Global Supply

• Precision machining: The production of quartz focus rings imposes extremely high accuracy requirements, calling for advanced 5-axis CNC machining and polishing technologies. Key dimensional tolerances can be controlled within ±0.02 mm or even ±0.001 mm, with surface roughness (Ra) lower than 0.002 μm.
• Major manufacturers: Key players in the global market include international leaders such as Entegris, CoorsTek, Heraeus Quartz and Tosoh Quartz, as well as Chinese enterprises like Dunyuan Juxin, Zhenbao Technology and Jingge Semiconductor. The products are generally compatible with mainstream etching platforms from Applied Materials (AMAT), such as MXP+ and Centura series.