Deep reactive ion etching (DRIE) is widely used in MEMS fabrication processes for creating high-aspect ratio anisotropic features. Further, the etch performance is dependent on open area (OA), that is, the amount of area subject to the etch process, which can range from 1% to 60%. It is also dependent on geometric pattern loading effects, the depth of the etch, the materials to be etched and their preparation. The optimal parameters values chosen vary widely according to the type of MEMS device and application. In addition, each tool type—and often each process chamber—has unique recipe settings for optimum etch performance for each material (typically silicon or silicon dioxide) and pattern. These settings include gas flows, duration, temperature profile, etc. The chamber’s environmental conditions also play a role in etch performance and are usually not known to the designer before bringing a design to the foundry. These variables lead to significant costs to both the designer and the foundry, as the process must be tuned to the specific pattern and material combination before production can commence.

This Document describes a set of etch test structures for characterizing the performance of DRIE process tools.

Referenced SEMI Standards (purchase separately)

SEMI 3D5 — Guide for Metrology Techniques to be Used in Measurement of Geometrical Parameters of Through-Silicon Vias (TSVs) in 3DS-IC Structures

Revision History

SEMI MS13-0221 (first published)