In the field of semiconductor manufacturing, the Showerhead (spray head/gas distribution plate), as a core component of the gas distribution system, directly determines the uniformity of thin-film deposition on wafer surfaces, etching precision, and the stability of plasma distribution. As advanced processes advance to the 3nm node and beyond, the microhole processing precision requirements for Showerheads have escalated to the sub-micron level, with pore diameter consistency needing to be controlled within ±0.5μm, posing a revolutionary challenge to traditional processing technologies.
I. Material Selection and Performance Requirements
Showerheads can be categorized into metal and non-metal types based on their materials:
Metal Materials: Aluminum alloys (6061-T6) are predominantly used due to their excellent thermal conductivity, strong corrosion resistance, and ease of processing, making them widely applicable in mid-to-low-end processes. In high-end fields, nickel-based alloys or titanium alloys are employed to resist plasma bombardment and high-temperature corrosion. For instance, Anhui Boxin Micro Semiconductor Technology Co., Ltd. utilizes nickel-based alloys to manufacture Showerheads in high-end processes, significantly enhancing their high-temperature and corrosion resistance.
Non-Metal Materials: These include chemical vapor deposition silicon carbide (CVD-SiC), aluminum nitride (AlN), quartz glass, and high-purity ceramics, primarily used in key processes such as extreme ultraviolet lithography (EUV) and atomic layer deposition (ALD). These materials must meet requirements such as high-temperature resistance (withstanding temperatures above 600°C in the reaction chamber), chemical inertness (resisting erosion by corrosive gases like Cl₂ and BCl₃), and thermal expansion matching (having a thermal expansion coefficient close to that of silicon wafers to prevent sealing failure due to high-temperature deformation).
II. Microhole Design and Processing Challenges
The core design parameters of Showerhead microholes include pore diameter (30-100μm, approaching 30μm in high-end processes), pore density (300-1200 pores/cm², with approximately 100,000 pores for a 12-inch wafer), pore shape error (≤±2μm to control gas flow rate consistency), and jet angle (requiring precise control to avoid gas turbulence). Taking Applied Materials' ALD Showerhead as an example, by optimizing pore diameter distribution and flow channel design, it has reduced the thin-film thickness deviation between the wafer edge and center regions from ±3% to ±0.8%, significantly improving yield.
Traditional processing technologies such as mechanical drilling and electrical discharge machining (EDM) face numerous limitations in Showerhead manufacturing:
Mechanical Drilling: Relying on hard alloy tools, it results in pore diameter deviations of up to 5μm due to tool wear and cannot process high-hardness materials like CVD-SiC.
EDM: By eroding materials through electrical discharges, it is suitable for conductive metals but generates a heat-affected zone (HAZ), with recast layers easily forming on the processed hole walls, requiring subsequent acid pickling for removal. Moreover, it is inefficient, necessitating over 10 tool changes and taking more than 20 hours to process a single 12-inch Showerhead.
III. Breakthroughs in Innovative Processing Technologies
To overcome the limitations of traditional technologies, the industry has adopted a series of innovative processing technologies:
Femtosecond Laser Cold Processing: Femtosecond lasers (with pulse widths <10⁻¹⁵ seconds) achieve "cold processing" through ultra-short pulses, resulting in no HAZ (with an HAZ width ≤0.2μm), avoiding damage to the material's microstructure, pore diameter deviations ≤±1μm, hole wall roughness Ra<0.2μm, and the ability to process high-hardness non-metals like CVD-SiC and aluminum nitride.
Composite Processing Techniques: The "laser + grinding" collaborative process is employed, where laser roughing rapidly forms microhole arrays, and diamond grinding precisely polishes the hole walls to eliminate taper and burrs left by laser processing. Anhui Boxin Micro has achieved mass production of 12-inch Showerheads using this process, with hole wall perpendicularity reaching 90°±0.5°, meeting the requirements of 5nm processes.
Atomic Layer Deposition (ALD) Pore Diameter Correction: ALD technology achieves nano-scale coating deposition through self-limiting surface reactions. Depositing 100 cycles (approximately 10nm) of SiO₂ can reduce the pore diameter by 0.2μm, with a correction precision of ±0.05μm and superior coating uniformity compared to traditional chemical vapor deposition (CVD).
IV. Future Trends and Challenges
Currently, Showerhead processing faces challenges such as cost pressures (femtosecond laser equipment costs over $5 million, with processing costs three times those of EDM), efficiency bottlenecks (a single laser equipment can only produce 5-10 12-inch Showerheads per day), and material defect control (non-metal materials are prone to hidden cracks during processing, requiring non-destructive testing methods like ultrasonic testing and X-ray computed tomography (X-CT)). In the future, with the development of technologies such as spatial ALD (increasing deposition rates to 1μm/min through parallel喷射 [simultaneous injection] of multiple precursors, reducing costs), AI simulation optimization (utilizing ANSYS Fluent combined with machine learning to shorten the gas flow channel design cycle by over 30%), and accelerated localization of substitutes, Showerhead processing will evolve towards higher precision, lower costs, and greater intelligence.
AMTD provides high-precision Showerhead (spray head/gas uniformity plate/gas distribution plate) services for core components. Its product range includes Showerheads, Face plates, Blocker Plates, Top Plates, Shields, Liners, pumping rings, Edge Rings, and other semiconductor equipment core parts. These products are widely used in semiconductors, display panels, and other fields, demonstrating exceptional performance and high market recognition.
Content Sources: Weiss Precision Tools "Application of Micro-Drills in the Semiconductor Key Component Industry," Tokyo Electron (TEL) Technical White Paper "Application of ALD in Showerhead Manufacturing," Lam Research "Processing Technologies for Core Components of Semiconductor Equipment," AMTD Technical Information.
