As a core equipment for semiconductor, microelectronics, and advanced material processing, the selection of plasma etching machines requires comprehensive consideration of multidimensional factors such as technical performance, process compatibility, scalability, and service support. The following will elaborate on the key purchasing points:
1、 Technical principles and model selection
Plasma etching machine ionizes gas with radio frequency or microwave energy to generate plasma, and uses the synergistic effect of physical bombardment and chemical reaction to achieve material removal. The mainstream models include:
-Reactive ion etching (RIE): relying on capacitive coupled plasma, suitable for etching basic materials, with low cost but limited uniformity.
-Inductively Coupled Plasma (ICP): Generate high-density plasma through high-frequency electromagnetic fields, with high etching rate (up to 1 μ m/min) and low damage characteristics (ion energy<10eV), suitable for processing aspect ratio structures.
-Atomic Layer Etching (ALE): Based on the "deposition reaction stripping" cycle, it can achieve sub nanometer precision and is suitable for 3D NAND stack layer etching.
2、 Core performance parameters
-Etching accuracy and uniformity: Advanced processes (such as below 3nm) require equipment with an on-chip uniformity of ≤± 1% and sidewall roughness controlled within 1nm. The temperature control range of Oxford PlasmaPro System 133 ICP380 can reach -20 ℃~80 ℃, ensuring the consistency of complex structures.
-Temperature control system: Dynamic temperature control directly affects the etching rate and morphology. The Sentech SI 500 series adopts helium back cooling technology and supports wide range adjustment from -150 ℃ to+400 ℃. The low-temperature mode can reduce sidewall damage caused by optical device etching.
3、 Process compatibility and scalability
-Multi material adaptability: It is necessary to verify the etching performance of the equipment on silicon-based, compound semiconductor (GaN/SiC), metal (Cu/Al), and dielectric materials. For example, Cl ₂/BCl ∝ mixed gas is suitable for copper interconnect etching, while SF ₆ is more suitable for aluminum processing.
-Modular design: Cluster equipment is recommended for mass production scenarios, supporting up to 5 process module integrations, compatible with ALD coating and PECVD deposition, achieving one-stop processing.
4、 Intelligence and Service
-Intelligent control system: Prioritize equipment equipped with AI algorithms, which can optimize gas ratio and power parameters in real time, reducing manual intervention errors. Some models have built-in OES spectral monitoring to accurately determine the etching endpoint and avoid over etching problems.
-Supplier Capability: Evaluate the vendor's localized technical support network and after-sales response speed. Leading brands such as Oxford Instruments provide full lifecycle maintenance, including regular calibration, spare parts replacement, and process database updates.
5、 Cost benefit analysis
-Full cycle cost accounting: In addition to the initial procurement cost, it is necessary to evaluate energy consumption (the power consumption of ICP models is about 1.5 times that of RIE), maintenance frequency, and capacity utilization rate. Taking the 300mm wafer production line as an example, although the unit price of ICP equipment is high, its etching rate advantage can reduce the cost of a single wafer by more than 20%.