Anisotropically Etched Standard Sample for 1 nm Line Edge Roughness
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Solution Overview
Problem
Current standard samples are inadequate for accurately evaluating line edge roughness on the order of 1 nm due to indefinite pattern edges and insufficient resolution, limiting their effectiveness in assessing nanometer-scale defects in semiconductor manufacturing.
Innovation Solution
A standard sample is manufactured with a substrate having a (110) plane and recesses formed through anisotropic etching, featuring a side surface that is a facet surface tilted from a (111) plane, enabling precise evaluation of line edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods (deposition, lithography, etching) are used to create periodical patterns, then the patterns can be formed with nanometer size, but line edge roughness of nanometer size is generated in the edge portion making it difficult to distinguish from defects
Solution Approach 1:
Instead of using conventional methods to create patterns and then trying to measure their edges (which generates LER), the invention inverts the approach by creating a standard sample with a known, controlled geometric structure (recess with facet surface) that serves as a reference. This allows the measurement system to be calibrated against a known standard rather than trying to measure the rough edges of manufactured patterns.
Solution Approach 2:
The invention creates a standard sample that copies or replicates a known geometric structure (recess with specific facet orientation) that can be used as a reference model. This standard sample mimics the structural features needed for measurement but with controlled, known geometry that allows for accurate evaluation of measurement systems.
2Measurement precision
If standard samples with minimum structure size of 100 nm or less are used to guarantee resolution, then the resolution can be evaluated, but the shape of the pattern edge remains indefinite
Solution Approach 1:
The invention applies local quality by creating a standard sample with specific local geometric features (recess structure with facet surface at known orientation) rather than relying on overall pattern size. The local geometry of the recess and its facet surface provides well-defined edges for measurement, while the overall sample structure maintains the necessary nanometer-scale dimensions for resolution evaluation.
3Measurement precision
If existing standard samples (NIST nanowire 130 nm, AIST tungsten-dot array 119 nm) are used, then the minimum size can be evaluated, but they cannot accurately evaluate unevenness on several nm order
Solution Approach 1:
The invention changes the geometric parameters of the standard sample by creating a recess structure with specific dimensions and facet orientations that are optimized for measuring nanometer-scale unevenness. The facet surface is oriented at a specific angle relative to the substrate surface, creating well-defined edges that are suitable for high-precision measurement of line edge roughness at the nanometer scale.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sample allows for the evaluation of line edge roughness on the order of 1 nm, providing accurate calibration for scanning probe microscopes like AFM and CD-SEM.
Implementation Method 1
etching the substrate by etching processing with crystal anisotropy using the mask pattern as a mask
Data Source
AI summary
A substrate (101) is etched by etching processing with crystal anisotropy, thereby forming a recess (104) from the main surface of the substrate (101) to the inside of the substrate (101). A side surface (105) is almost a (111) plane, and the etching hardly progresses. As a result, a cross section of the recess (104) perpendicular to the longitudinal direction has a rectangular shape. Since an opening (103) of a mask pattern (102) has a rectangular shape in a planar view, the opening of the recess (104) has a rectangular shape in a planar view, and the recess (104) is formed into, for example, a rectangular parallelepiped shape. The recess (104) includes a side surface (105) that forms one plane perpendicular to the main surface of the substrate (101). The side surface (105) is a facet surface and is a tilting surface tilted from the (111) plane.