The Co-evolution of High-Precision Showerhead Manufacturing and Semiconductor Processes

I. Showerhead: The "Gas Distribution Hub" in Semiconductor Processes

Core Functions

Uniform Gas Distribution: Through densely distributed micropores (diameter: 0.2–6 mm), etch/deposition gases are uniformly sprayed onto the wafer surface to avoid local concentration variations.

Corrosion and High-Temperature Resistance: Long-term exposure to highly corrosive fluorine-based gases and high-temperature environments requires high chemical stability.

Ultra-High Cleanliness: Surface particle contamination ≤0.1 μm to prevent wafer defects.

Manufacturing Requirements

Micropore Precision: Pore diameter consistency within ±0.01 mm; inner wall roughness ≤Ra0.2 μm.

Surface Flatness: Overall planarity ≤±2 μm to ensure sealing performance.

Material Purity: High-purity alumina/aluminum nitride or specialty alloys with impurity content < ppm level.

II. High-Precision Machining: The "Soul" of Showerhead Manufacturing

Micropore Fabrication Technologies

Laser Drilling: High-energy laser melting for small-batch, high-precision machining (pore diameter: 0.1–1 mm).

Electron Beam Welding: Utilizes high-energy density for micropore forming in difficult-to-machine materials like aluminum nitride.

Multi-Axis Machining Centers: Multi-axis tool path control enables high-precision machining of complex curved micropores.

Case Study: A company employed a laser + grinding process to machine a Φ300 mm showerhead with 1,000 Φ0.45 mm through-holes, achieving a pore diameter tolerance <±0.01 mm.

Surface Flatness Control

Ultra-Precision Grinding: Diamond abrasive polishing achieves planarity of ±1 μm.

Scraping Technology: Manual scraping corrects micro-errors for high-precision planar surfaces.

Case Study: Nano-level surface finish treatment on an electrostatic chuck (ESC) achieved protrusion diameter/depth accuracy <1 μm.

Material Selection and Treatment

High-Purity Material Preparation: CVD or hot-press sintering for high-purity alumina/aluminum nitride.

Surface Coatings: PVD or electroless plating to form SiC/nitride corrosion-resistant coatings.

III. How Machining Precision Defines the "Vitality" of Showerheads

Gas Distribution Uniformity

Micropore machining precision directly impacts gas flow distribution. Excessive pore diameter tolerance or inner wall burrs cause inconsistent flow velocities, leading to uneven wafer surface film thickness (e.g., etch rate variations >5%).

Research Example: Increasing micropore diameter improves radial velocity and temperature uniformity; reducing diameter optimizes radial pressure distribution.

Equipment Longevity and Stability

High-precision machining reduces internal material stress, lowering deformation risks under high temperatures. For instance, hot isostatic pressing (HIP) eliminates porosity to enhance thermal shock resistance.

Surface roughness optimization minimizes gas adsorption and particle adhesion, extending cleaning cycles from 50 to 200 hours.

Process Compatibility

Precision machining ensures exact alignment between the showerhead and reaction chamber/wafer chuck to prevent leaks or mechanical interference.

Corporate Example: A company designed machining processes using error absorption principles to achieve fit gaps <0.05 mm.

IV. Industry Benchmarks and Future Trends: The Evolutionary Path of Showerheads

Industry Case Studies

AMTD: Focuses on R&D and high-precision micropore machining using five-axis centers, with products spanning semiconductor/display panel applications.

An International Enterprise: Optimized porous structures and gas flow simulations to boost gas utilization to 95%, significantly reducing costs.

Technological Trends

Hybrid Machining Technologies: Combines laser, EDM, and ultrasonic vibration to enhance ceramic/specialty alloy machining efficiency.

Smart Manufacturing: Introduces in-line inspection and adaptive machining systems for batch consistency control of micropore arrays.

Sources: Wanfang Data Knowledge Service Platform, WeChat Public Platform (Tencent), Zhihu Column, etc.