Discover the SENTECH modular and flexible plasma processing systems for low-damage, high-rate, and high-selectivity etching.
Understanding plasma etching techniques: RIE, ICP-RIE, DRIE, Cryogenic Etching, and ALE
Plasma etching is a cornerstone process in semiconductor device fabrication, enabling the precise removal of materials from a substrate through chemical reactions driven by ionised gases. Unlike traditional wet etching, which uses liquid chemicals and often produces isotropic profiles, plasma etching provides anisotropic, highly controlled material removal. This precision is essential for the miniaturisation and performance of modern microelectronic, MEMS, and photonic devices.
The process uses a plasma, a partially ionised gas containing ions, electrons, and reactive neutral species. When directed toward a substrate, these energetic particles chemically and physically interact with the material, selectively etching away exposed areas while preserving masked regions. The result is a clean, defined pattern transfer, a fundamental requirement in advanced semiconductor production.
Find out more about our modular and versatile plasma etching tools. To learn more about the different plasma processing techniques and how they are fundamental to the development of modern semiconductor applications, scroll on.
Reactive Ion Etching (RIE) combines chemical etching with physical ion bombardment to deliver precise pattern transfer. In RIE systems, a plasma is generated between two electrodes using a radio frequency (RF) power source. Reactive species chemically react with the substrate surface while positive ions accelerate toward it, physically sputtering atoms away.
RIE is ideal when moderate anisotropy and process control are required. It is widely used in:
Its balance of chemical and physical mechanisms makes RIE versatile and cost-effective for both research and production.
The key to RIE’s success lies in the balance between ion energy and chemical reactivity. Adjusting gas composition, pressure, and RF power allows engineers to tune the process for optimal etch rate, selectivity, and sidewall profile, ensuring reliable, repeatable results across wafers.
Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) represents the next generation of plasma etching technology. It separates plasma generation and ion acceleration into two independently controlled systems:
This dual control enables deeper etching, improved anisotropy, and minimal substrate damage.
As semiconductor devices become smaller and more complex, ICP-RIE allows for precise etching of high-aspect-ratio structures with superior sidewall quality. It is indispensable in applications such as:
ICP-RIE systems allow independent adjustment of plasma density and ion energy, giving process engineers fine control over etch uniformity, selectivity, and profile. This ensures repeatable, high-yield results, even in advanced node technologies.
Deep Reactive Ion Etching (DRIE) is a specialised extension of ICP-RIE designed for deep, narrow trench and via etching in silicon and other materials. It alternates between etching and passivation steps, allowing vertical sidewalls and depths exceeding hundreds of micrometres.
DRIE is critical for MEMS fabrication, through-silicon vias (TSVs), and power semiconductor devices. It enables engineers to build three-dimensional structures essential for sensors, actuators, and packaging technologies.
DRIE typically uses the Bosch process, which alternates between a fluorine-based etch phase and a polymer deposition phase. This creates a near-vertical sidewall profile, essential for reliable device performance and integration density.
Cryogenic etching operates at extremely low substrate temperatures (typically below −100°C). This temperature control reduces chemical reaction rates at unwanted surfaces, enabling smooth, damage-free sidewalls without polymer deposition.
Cryogenic etching is ideal for optical and photonic applications, where surface smoothness is critical, and residue-free profiles are essential. It is commonly used in:
By cooling the substrate, the process limits spontaneous chemical reactions, ensuring that etching only occurs where ion energy is directed — delivering ultra-clean results with high selectivity and minimal roughness.
Atomic Layer Etching (ALE) is a next-generation plasma etching technique that removes material at the atomic scale, one layer at a time. It uses self-limiting surface reactions to achieve unparalleled precision and uniformity.
ALE is vital for sub-10 nm semiconductor nodes, quantum devices, and 2D material processing, where even nanometre-level deviations can affect device performance. It offers atomic-level control over etch rate, selectivity, and surface damage, critical for scaling beyond current lithography limits.
Plasma etching underpins nearly every modern semiconductor manufacturing process, from transistor gate definition to MEMS sensor release. Its ability to deliver nanometre-scale accuracy, material selectivity, and repeatability makes it indispensable for industries including:
Without plasma etching, the miniaturisation, performance, and reliability of today’s electronic devices would be impossible.
SENTECH Instruments is a global leader in plasma etching technology, providing advanced RIE, ICP-RIE, DRIE, Cryogenic, and ALE systems designed for both research and high-volume production environments.
SENTECH plasma etch systems deliver:
With intuitive software control, low maintenance requirements, and reproducible performance, SENTECH plasma etching systems empower semiconductor engineers and researchers to push the boundaries of micro- and nanofabrication.
SENTECH plasma etching technologies continue to evolve, enabling finer structures, better device performance, and higher manufacturing yields. SENTECH’s advanced plasma etching systems offer the precision, flexibility, and reliability required to meet the challenges of next-generation semiconductor device fabrication.
