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Method for measuring the trench depth of a very-large-scale-integration dynamic random-access memory capacitor based
Optics Letters
|September 10, 2009
Summary
A new method precisely measures trench depth in dynamic random-access memory capacitor cells. This technique uses a Michelson interferometer for accurate, sub-micrometer error measurements in semiconductor manufacturing.
Area of Science:
- Semiconductor Device Fabrication
- Metrology
- Optical Interferometry
Background:
- Accurate trench depth measurement is critical for advanced semiconductor manufacturing, particularly for dynamic random-access memory (DRAM) capacitor cells.
- Existing metrology methods may lack the precision required for sub-micron feature characterization in very-large-scale-integration (VLSI) circuits.
Purpose of the Study:
- To propose a simple and precise method for measuring the trench depth of VLSI DRAM capacitor cells.
- To demonstrate the feasibility of using optical interferometry for sub-micrometer metrology in semiconductor fabrication.
Main Methods:
- Development of a measurement system based on a Michelson interferometer.
- Utilizing a silicon wafer with trenches as a reflecting mirror within the interferometer setup.
- Implementing optical interference principles for precise depth determination.
Main Results:
- Successful demonstration of a simple trench depth measurement system.
- Achieved measurement precision of within 0.2-micrometer error for DRAM capacitor cell trenches.
- Validated the effectiveness of the Michelson interferometer for high-precision semiconductor metrology.
Conclusions:
- The proposed Michelson interferometer-based method offers a simple and highly accurate approach for measuring trench depths in VLSI DRAM capacitor cells.
- This technique provides a valuable tool for quality control and process optimization in advanced semiconductor manufacturing.
- The sub-micrometer precision achieved highlights the potential of optical interferometry for next-generation device fabrication metrology.
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