In the microscopic world of semiconductor manufacturing, the Showerhead (also known as a spray shower or gas distribution plate) acts like a precise gas conductor. Through its surface featuring tens of thousands of micro-hole arrays, it evenly sprays reactive gases onto the wafer surface, directly influencing the uniformity of thin-film deposition, etching precision, and the stability of plasma distribution. As advanced processes advance towards the 3nm node and beyond, the processing precision requirements for the micro-holes of the Showerhead have escalated to the sub-micron level, with pore diameter consistency needing to be controlled within ±0.5μm. This poses a revolutionary challenge to traditional processing technologies and has spurred the emergence of a series of innovative processing techniques.
Material Selection: Dual Considerations of Performance and Process
Showerheads can be classified into metal and non-metal categories based on their materials. Among metal materials, aluminum alloy (6061-T6) is widely used in mid- to low-end processes due to its good thermal conductivity, strong corrosion resistance, and ease of processing. In high-end fields, nickel-based alloys or titanium alloys are the preferred choices as they can withstand plasma bombardment and high-temperature corrosion, providing reliable protection for semiconductor manufacturing. For example, Anhui Boxinwei Semiconductor Technology Co., Ltd. uses nickel-based alloys to manufacture Showerheads in high-end processes, significantly enhancing their high-temperature and corrosion resistance to meet the stringent requirements of advanced processes.
Non-metal materials also play a crucial role in Showerhead manufacturing. Materials such as chemical vapor deposition silicon carbide (CVD-SiC), aluminum nitride (AlN), quartz glass, and high-purity ceramics are mainly used in key processes like 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 from corrosive gases like Cl₂ and BCl₃), and thermal expansion matching (having a thermal expansion coefficient close to that of silicon wafers to avoid sealing failure due to high-temperature deformation). Taking CVD-SiC as an example, it possesses extremely high hardness and excellent high-temperature resistance, enabling it to maintain stable performance in extreme environments and providing reliable support for semiconductor manufacturing.
Limitations and Challenges of Technologies
In the manufacturing history of Showerheads, traditional processing technologies such as mechanical drilling and electrical discharge machining (EDM) once dominated. However, as process nodes continue to advance, these technologies have gradually revealed numerous limitations.
Mechanical drilling relies on cemented carbide tools, but tool wear can lead to pore diameter deviations of up to 5μm, and it is unable to process high-hardness materials (such as CVD-SiC). During the processing, friction between the tool and the material generates a large amount of heat, exacerbating tool wear and thus affecting processing accuracy. Additionally, for high-hardness materials, mechanical drilling has extremely low efficiency and may even be unable to complete the processing task.
EDM erodes materials through electrical discharges and is suitable for conductive metals. However, it has a heat-affected zone (HAZ), and the processed hole walls are prone to developing a recast layer, which requires subsequent acid washing for removal. Moreover, EDM is inefficient, requiring more than 10 tool changes and taking over 20 hours to process a single 12-inch Showerhead. During long-term processing, the heat-affected zone can cause changes in the material's microstructure, affecting the performance and reliability of the Showerhead.
Breakthroughs and Applications of Innovative Processing Technologies
To overcome the limitations of traditional technologies, the industry has adopted a series of innovative processing technologies, bringing new breakthroughs to Showerhead manufacturing.
Femtosecond laser cold processing technology achieves a "cold processing" effect thanks to its ultra-short pulses and ultra-high peak power, with no heat-affected zone (HAZ width ≤ 0.2μm), avoiding damage to the material's microstructure. This technology has a pore diameter deviation of ≤ ±1μm and a hole wall roughness Ra < 0.2μm, and can process high-hardness non-metals such as CVD-SiC and aluminum nitride. For example, in 3nm process equipment, some Showerheads use femtosecond laser drilling technology, which can precisely drill micro-holes in molybdenum-based materials while maintaining extremely high hole wall smoothness (Ra < 0.3μm), providing a higher-precision gas distribution solution for semiconductor manufacturing.
The composite processing technology adopts a "laser + grinding" collaborative process. First, laser rough processing is used to quickly form the micro-hole array, and then diamond grinding is employed to precisely polish the hole walls, eliminating the taper and burrs left by laser processing. Anhui Boxinwei has achieved mass production of 12-inch Showerheads through this process, with a hole wall perpendicularity of 90°±0.5°, meeting the requirements of 5nm processes and providing strong support for the high-end development of the semiconductor industry.
Atomic layer deposition (ALD) pore size correction technology achieves nano-scale coating deposition through self-limiting surface reactions. Depositing 100 cycles (about 10nm) of SiO₂ can reduce the pore diameter by 0.2μm, with a correction accuracy of ±0.05μm and better coating uniformity than traditional chemical vapor deposition (CVD). In EUV lithography mask manufacturing, Tokyo Electron used this technology to reduce the coefficient of variation (CV) of the Showerhead's spray hole diameter from ±3% to ±0.5%, significantly improving the exposure uniformity of the photoresist and providing a key guarantee for enhancing the precision of semiconductor manufacturing.
Future Trends and Prospects
Currently, Showerhead processing faces challenges such as cost pressure (femtosecond laser equipment costs over $5 million, and the processing cost is three times that of EDM), efficiency bottlenecks (a single laser equipment has a daily production capacity of only 5 - 10 12-inch Showerheads), and material defect control (non-metal materials are prone to hidden cracks during processing, requiring non-destructive testing combining ultrasonic testing and X-ray computed tomography (X-CT)). However, with continuous technological progress, new development opportunities for Showerhead processing will emerge in the future.
Spatial ALD technology increases the deposition rate to 1μm/min by using multi-precursor parallel injection, which is expected to reduce costs and improve production efficiency. AI simulation optimization, using ANSYS Fluent combined with machine learning, can shorten the gas flow channel design cycle by more than 30%, accelerating product research and development and iteration. In terms of domestic substitution acceleration, domestic companies such as Weiss Precision Tools and Dunyuan Juxin have achieved the localization of PCD micro-drills and femtosecond laser equipment, increasing the localization rate of the industrial chain from 15% to 40% and providing strong support for the independent and controllable development of the semiconductor industry.
Showerhead production and processing technology is a typical representative of "small holes, big technology" in semiconductor manufacturing, and its precision directly determines the yield and cost of advanced processes. With breakthroughs in technologies such as femtosecond laser, composite processing, and ALD correction, the industry is gradually overcoming sub-micron processing challenges. In the future, with the deep integration of materials science, intelligent manufacturing, and AI technology, Showerhead processing will evolve towards higher precision, lower cost, and greater intelligence, providing key support for the continuous innovation of the semiconductor industry.
AMTD provides high-precision Showerhead (spray shower/gas uniformity plate/gas distribution plate) services for core components. Its products mainly include Showerheads, Face plates, Blocker Plates, Top Plates, Shields, Liners, pumping rings, Edge Rings, and other core semiconductor equipment components. These products are widely used in fields such as semiconductors and display panels, with excellent performance and high market recognition.
Content sources: Weiss Precision Tools' "Application of Micro-drills in the Semiconductor Key Component Industry", Tokyo Electron (TEL)'s technical white paper "Application of ALD in Showerhead Manufacturing", Lam Research's "Processing Technologies for Core Components of Semiconductor Equipment", and Anhui Boxinwei Semiconductor Technology Co., Ltd.'s official website information.
