Semiconductor Core Components - Showerhead (Gas Distribution Plate)

The semiconductor showerhead (also known as a Gas Distribution Plate or GDP) is a core component in semiconductor manufacturing equipment. It plays a critical role throughout key processes such as cleaning, etching, and deposition, directly impacting process precision and product quality. It serves as the key hardware responsible for gas distribution.

It is a gas dispersion apparatus widely used in semiconductor fabrication. Its primary function is to distribute process gases uniformly into the reaction chamber, ensuring even contact with the semiconductor material to enhance production efficiency and product yield. These products feature high precision, high cleanliness, and multi-level surface treatments (integrating sandblasting, anodizing, brush nickel plating, electropolishing, etc.). Located inside the process chamber, the GDP provides a uniform gas film layer for the wafer processing environment, making it a pivotal element in wafer production.

During the wafer reaction process, the showerhead surface is densely populated with micro-holes (diameters ranging from 0.2 to 6 mm). Through precisely engineered channel structures and gas pathways, process gases pass through thousands of tiny holes on the GDP to deposit uniformly on the wafer surface. The film thickness across different regions of the wafer must guarantee high uniformity and consistency. Therefore, besides extreme requirements for cleanliness and corrosion resistance, the GDP has stringent specifications regarding hole diameter consistency and internal wall burrs. Excessive dimensional tolerances, large standard deviations in consistency, or the presence of burrs on any internal wall can lead to uneven deposition thickness, directly affecting tool yield. In plasma-assisted processes (such as PECVD and dry etching), the showerhead acts as part of the electrode. By applying RF power, it generates a uniform electric field to promote even plasma distribution, thereby enhancing the uniformity of etching or deposition.

Materials & Manufacturing

Material Types:
Depending on the material, Showerheads can be categorized into:

Silicon-type (also called Silicon Electrode)Metal-type (Aluminum alloy, Stainless steel, Pure Nickel, etc.)Other types (e.g., CVD-SiC Showerhead)

Common Metals:

7075 Aluminum Alloy / Stainless Steel: Primarily used for manufacturing showerheads with larger aperture diameters (2-6 mm). This requires small machining centers with spindle speeds as high as 18,000 or 30,000 RPM, utilizing electro-spindles to ensure machining accuracy.

Advanced Ceramics:

CVD Silicon Carbide (CVD-SiC): Suitable for high-demand applications like etch equipment. Although domestically produced CVD-SiC showerheads cost around 150,000 RMB, their machining precision is currently limited, resulting in continued reliance on imported products.Single Crystal Silicon / Quartz Glass: These brittle materials require specialized ultrasonic drilling and tapping machines. Ultrasonic vibration is utilized to lower cutting temperatures and facilitate chip removal to prevent breakage.High-Purity Ceramics (Alumina, Silicon Nitride): Commonly used in high-temperature and high-pressure environments due to their stability and corrosion resistance, accounting for 79% of the global market share.Silicon-type Showerhead: The mainstream choice (79% market share), priced at approximately 80,000–90,000 RMB. Its lifespan is affected by plasma corrosion, necessitating regular replacement.

MOCVD Reactor Chamber Showerhead Manufacturing

MOCVD reactor chamber showerheads are typically manufactured using high-purity ceramic materials such as alumina and silicon nitride. Ceramics offer excellent high-temperature stability and corrosion resistance, enabling stable operation under high pressure and temperature while minimizing contamination of the process gases.

The main manufacturing aspects include:

Material Selection: Selecting appropriate high-purity ceramics based on process gas characteristics and operating conditions.Structural Design: Designing the geometric shape and positioning of the showerhead according to the chamber's dimensions to optimize compound uniformity and stability.Machining Processes: Utilizing mechanical machining, Hot Isostatic Pressing (HIP), and injection molding to fabricate the material into the required design.Material Impact: The material choice directly affects performance and service life. Metals are typically used for low-temperature growth, whereas ceramics are suited for high-temperature and high-pressure conditions.Surface Treatment: Processes such as polishing, sandblasting, and chemical etching are employed to improve surface flatness and smoothness, further enhancing growth efficiency and material quality.