By SAMCO Inc.
Samco has developed ALE capabilities by incorporating ALE functions into conventional Inductively Coupled Plasma (ICP) etching systems. As a result, a single system can be used for both ICP etching and ALE. Samco’s ALE systems incorporate the following two technical capabilities: Precise Control in the Low Bias Power Range Samco systems include an attenuator and switching unit in the high-frequency transmission line of the bias power supply. In order to ensure that only the modified layer is etched during ALE, precise control in the extremely low output range is required, and the optimal control range varies depending on the material. The attenuator adjusts the ion energy reaching the substrate from the plasma, enabling precise control in the low bias-power range. In addition to the attenuator, Samco also enhances control performance through bias power monitoring using a power meter, ensuring stable and repeatable operation. Improvement of Gas Switching Speed To improve gas switching speed in the reaction chamber, an ALE specific gas box is positioned in close proximity to the chamber. Since ALE requires switching between gases for the modification and removal steps, minimizing the switching time is crucial for throughput improvement. Gas switching time depends strongly on both the length of the gas lines and the valve response time. Therefore, by shortening the piping configuration, switching speed is increased, modification reproducibility is maintained, and cycle time is reduced. In addition, in Quasi-ALE (a process similar to ALE that does not involve self-limiting reactions) the etch depth per cycle is determined by the thickness of the deposited etchant during the modification (deposition) step. Compared to ALE, higher gas switching precision is required to ensure reproducibility.
