High-Precision Plasma Etching: 3D-Printed Ceramic Gas Injector Optimizes Process Control

Semiconductor manufacturers are increasingly demanding equipment components that can withstand extreme plasma environments while enabling tighter process control and minimizing contamination. To meet these stringent requirements, Sinto Advanced Ceramics has leveraged additive manufacturing to consolidate a previously two-piece gas injector into a single, fully integrated ceramic component. By combining high-purity alumina with lithography-based additive manufacturing (AM), the company successfully realized complex internal geometries that significantly enhance reliability and performance in advanced wafer production.

Semiconductor manufacturing is known for its uncompromising material and process standards. Dry chemical etching, in particular, requires highly aggressive gases, demanding components that deliver exceptional chemical inertness and thermal stability, alongside micrometer-level precision and long-term stability during continuous operation. This case study demonstrates how ceramic additive manufacturing optimizes the performance of mission-critical process components.

Functional Integration Through Monolithic Design

The successful execution of this project by Sinto Advanced Ceramics—working in close collaboration with its customer and utilizing lithography-based ceramic manufacturing (the LCM process)—highlights the direct benefits of AM in optimizing process workflows and improving overall system reliability. Gas injectors are key components used to precisely introduce corrosive media into the etch chamber during wafer processing. While the conventional concept consisted of two separate parts, the final AM design integrates three internal channels and 62 flow-optimized outlets into a single, monolithic ceramic component. This integrated design significantly improves both process stability and material purity.

"Our customer was facing a challenge that could not be solved efficiently using conventional manufacturing methods, leaving substantial room for improvement in terms of functionality," explains Ashu Sharma, CSO of Bosch Advanced Ceramics (today Sinto Advanced Ceramics). "Ceramic additive manufacturing provided the ideal alternative, enabling seamless functional integration, enhanced component performance, and a profound optimization of the semiconductor process."

The component specifications were highly complex: it had to guarantee absolute gas-tightness over its entire service life, offer long-term resistance to aggressive process gases, and maintain tight tolerances of ±0.1 mm at the flange for flawless system integration. Under these conditions, conventional materials like metals are highly susceptible to corrosion, leading to material degradation and severe contamination. Plastics, on the other hand, quickly lose their structural integrity in plasma environments. Both material classes—metals in particular—also carry a high risk of particle generation, which must be strictly eliminated in semiconductor manufacturing.

Materials and Processes: Combining Alumina with AM Precision

Given these demanding operational environments, high-purity alumina (99.8% Al₂O₃) was selected. The material is characterized by its excellent chemical inertness, high thermal stability, and robust mechanical performance. This makes it uniquely suited for the aggressive conditions inside etching chambers while ensuring strict compliance with cleanroom requirements by minimizing contamination risks.

The gas injector features three internal channels, each 6 mm in diameter, and a total of 62 flow-optimized outlet orifices. In the nozzle area, ultra-thin wall thicknesses of just 0.2 mm were achieved. Ceramic additive manufacturing enables the realization of such complex internal architectures and delicate structures, which would be economically unfeasible or physically impossible to produce using conventional methods like machining or ceramic injection molding (CIM). At the same time, the process guarantees micrometer-level precision and excellent surface quality—both of which are essential prerequisites for reliable operation in semiconductor applications.

"Additive manufacturing allows us to create geometries that would be unthinkable with traditional methods, while achieving a maximum level of functional integration," emphasizes Nikolai Sauer, CTO of Bosch Advanced Ceramics (today Managing Director of Sinto Advanced Ceramics). "Merging the originally two-piece component into a single, optimized design reduces system complexity and enhances internal fluid dynamics through a flow-optimized structure."

A major technical hurdle during development was cleaning the complex internal channels after the printing process. Removing uncured slurry from curved, thin-walled structures requires precisely controlled process parameters. Sinto Advanced Ceramics developed proprietary, process-optimized cleaning methods to ensure these delicate geometries are cleaned thoroughly and reliably without causing damage. These validated processes form the technological foundation for guaranteeing reproducible quality in series production.

Performance Gains and Enhanced Equipment Efficiency

The ceramic gas injector has successfully transitioned into series production, with annual volumes fully scalable to meet industrial demand. The monolithic design simplifies assembly and eliminates vulnerable sealing interfaces, systematically eliminating potential leak paths. Concurrently, the optimized internal geometry improves the homogeneity of the gas distribution, directly contributing to more stable process conditions. Minimizing process fluctuations has a direct, positive impact on wafer yield and boosts overall manufacturing efficiency.

Furthermore, the high chemical resistance of the alumina ensures a significantly extended service life for the component under aggressive conditions. This translates into longer maintenance intervals, minimized unplanned downtime, and maximized equipment uptime. The simplified design also offers practical benefits during routine servicing: the self-contained component is much easier to handle and replace, reducing Mean Time to Repair (MTTR).

Ceramic 3D Printing: New Horizons for Equipment Design

This gas injector clearly demonstrates how ceramic 3D printing is revolutionizing component design in the semiconductor industry. The symbiosis of high-performance technical ceramics and the design freedom of additive manufacturing allows engineers to design components based entirely on functional requirements, completely free from the restrictions of conventional manufacturing. Technical ceramics deliver the required purity, chemical inertness, and thermal stability, while AM enables complex internal geometries and multi-functional integration within a single part. This minimizes assembly effort, reduces the risk of failure, and enhances overall system reliability. This application example highlights how additive manufacturing paves the way for next-generation components that effortlessly meet the rapidly growing demands of semiconductor fabrication.

An article about this component was published in PIM International magazine. The article can be found here.

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